1 State Research Center of the Russian Federation - Federal State Unitary Enterprise "Central Order of the Red Banner of Labor Research Automobile and Automotive Institute (NAMI)"
When converting a diesel to a gas engine, supercharging is used to compensate for the decrease in power. To prevent detonation, the geometric compression ratio is reduced, which causes a decrease in the indicated efficiency. Differences between geometric and actual compression rates are analyzed. Closing the intake valve by the same amount before or after BDC causes the same reduction in the actual compression ratio as compared to the geometric compression ratio. Comparison of the filling process parameters for the standard and shortened intake phases is given. It is shown that early closure of the intake valve allows the actual compression ratio to be reduced, lowering the knock threshold, while maintaining a high geometric compression ratio and high indicator efficiency. The shorter inlet provides an increase in mechanical efficiency by reducing the pressure of pumping losses.
gas engine
geometric compression ratio
actual compression ratio
valve timing
indicator efficiency
mechanical efficiency
detonation
pumping losses
1. Kamenev V.F. Prospects for improving the toxic performance of diesel engines vehicles weighing more than 3.5 t / V.F. Kamenev, A.A. Demidov, P.A. Shcheglov // Proceedings of NAMI: Sat. scientific. Art. - M., 2014. - Issue. No. 256. - P. 5–24.
2. Nikitin A.A. Variable valve drive for the inlet of the working medium into the engine cylinder: Pat. 2476691 Russian Federation, IPC F01L1 / 34 / A.A. Nikitin, G.E. Sedykh, G.G. Ter-Mkrtichyan; applicant and patentee SSC RF FSUE "NAMI", publ. 02/27/2013.
3. Ter-Mkrtichyan G.G. Engine with quantitative throttle-free power control // Automotive Industry. - 2014. - No. 3. - P. 4-12.
4. Ter-Mkrtichyan G.G. Scientific foundations for creating engines with a controlled compression ratio: dis. doct. ... tech. sciences. - M., 2004 .-- 323 p.
5. Ter-Mkrtichyan G.G. Controlling the movement of pistons in internal combustion engines. - M.: Metallurgizdat, 2011 .-- 304 p.
6. Ter-Mkrtichyan G.G. Trends in the development of storage fuel systems for large diesels / G.G. Ter-Mkrtichyan, E.E. Starkov // Proceedings of NAMI: Sat. scientific. Art. - M., 2013. - Issue. No. 255. - P. 22–47.
Recently, gas engines, convertible from diesel engines, are widely used in trucks and buses by modifying the cylinder head with replacing the nozzle with a spark plug and equipping the engine with equipment for supplying gas to the intake manifold or to the intake ducts. To prevent detonation, the compression ratio is lowered, as a rule, by modifying the piston.
A gas engine has a priori lower power and worse fuel efficiency compared to the base diesel engine. The decrease in the power of the gas engine is explained by the decrease in the filling of the cylinders with the fuel-air mixture due to the replacement of part of the air with gas, which has a larger volume compared to liquid fuel. To compensate for the decrease in power, supercharging is used, which requires an additional decrease in the compression ratio. At the same time, the indicator efficiency of the engine decreases, accompanied by a deterioration fuel efficiency.
A diesel engine of the YaMZ-536 family (6ChN10.5 / 12.8) with a geometric compression ratio was chosen as the base engine for converting to gas. ε = 17.5 and a rated power of 180 kW at a crankshaft speed of 2300 min -1.
Fig. 1. Dependence of the maximum power of the gas engine on the compression ratio (knock limit).
Figure 1 shows the dependence of the maximum power of a gas engine on the compression ratio (knock boundary). In a converted engine with standard valve timing, the specified rated power of 180 kW without detonation can be achieved only with a significant decrease in the geometric compression ratio from 17.5 to 10, which causes a noticeable decrease in the indicated efficiency.
Avoid detonation without a decrease or with a minimum decrease in the geometric compression ratio, and therefore a minimum decrease in the indicator efficiency, is made possible by the implementation of a cycle with early closing of the intake valve. In this cycle, the intake valve closes before the piston reaches BDC. After closing the intake valve, when the piston moves to BDC, the gas-air mixture first expands and cools, and only after the piston passes BDC and moves to BDC does it begin to compress. Cylinder filling losses are compensated for by increasing the boost pressure.
The main objectives of the research were to identify the possibility of converting a modern diesel engine into a gas engine with external mixture formation and quantitative regulation while maintaining high power and fuel efficiency of the base diesel. Let's consider some of the key points of approaches to solving the assigned tasks.
Geometric and actual compression ratios
The beginning of the compression process coincides with the moment of closing the intake valve φ a... If this happens at BDC, then the actual compression ratio ε f is equal to the geometric compression ratio ε. With the traditional organization of the working process, the inlet valve closes 20-40 ° after BDC in order to improve filling due to recharging. In the short inlet cycle, the inlet valve closes to BDC. Therefore, in real engines, the actual compression ratio is always less than the geometric compression ratio.
Closing the intake valve by the same amount either before or after BDC causes the same decrease in the actual compression ratio compared to the geometric compression ratio. So, for example, with a change in φ a 30 ° before or after BDC, the actual compression ratio is reduced by about 5%.
Changing the parameters of the working fluid during filling
During the research, the standard exhaust phases were retained, and the intake phases were changed due to the variation of the intake valve closing angle φ a... In this case, with early closing of the intake valve (before BDC) and maintaining the standard intake duration (Δφ vp= 230 °), the intake valve would have to be opened long before TDC, which, due to the large valve overlap, would inevitably lead to an excessive increase in the residual gas ratio and disturbances in the course of the working process. Therefore, early closure of the intake valve required a significant reduction in intake duration to 180 °.
Figure 2 shows a diagram of the charge pressure during filling depending on the closing angle of the intake valve to BDC. End pressure p a the lower the pressure in the intake manifold, and the decrease in pressure is the greater, the earlier the intake valve closes before BDC.
When closing the intake valve at TDC, the charge temperature at the end of filling T a slightly higher temperature in the intake manifold T k... When the intake valve closes earlier, the temperatures approach, and when φ a> 35 ... 40 ° PCV, the charge during filling is not heated, but cooled.
1 - φ a= 0 °; 2 - φ a= 30 °; 3 - φ a= 60 °.
Fig. 2 Influence of the closing angle of the intake valve on the change in pressure during filling.
Optimization of the intake phase at rated power mode
All other things being equal, boosting or increasing the compression ratio in engines with external mixture formation are limited by the same phenomenon - the occurrence of detonation. Obviously, with the same excess air ratio and the same ignition timing, the conditions for the occurrence of detonation correspond to certain pressure values p c and temperature T c charge at the end of compression, depending on the actual compression ratio.
With the same geometric compression ratio and, therefore, the same compression volume, the ratio p c/ T c uniquely determines the amount of fresh charge in the cylinder. The ratio of the pressure of the working fluid to its temperature is proportional to the density. Therefore, the actual compression ratio shows how much the density of the working fluid increases during the compression process. The parameters of the working fluid at the end of compression, in addition to the actual compression ratio, are significantly influenced by the pressure and temperature of the charge at the end of filling, which are determined by the course of gas exchange processes, primarily the filling process.
Consider engine options with the same geometric compression ratio and the same average indicated pressure, one of which has a standard intake duration ( Δφ vp= 230 °), and in the other the inlet is shortened ( Δφ vp= 180 °), the parameters of which are presented in Table 1. In the first version, the inlet valve closes 30 ° after TDC, and in the second version, the inlet valve closes 30 ° before TDC. Therefore, the actual compression ratio is ε f the two variants with late and early closing of the intake valve are the same.
Table 1
Working fluid parameters at the end of filling for standard and short inlet
|
Δφ vp, ° |
φ a, ° |
P k, MPa |
P a, MPa |
ρ a, kg / m 3 |
||
The average indicated pressure at a constant value of the excess air ratio is proportional to the product of the indicated efficiency by the amount of charge at the end of filling. The indicator efficiency, other things being equal, is determined by the geometric compression ratio, which is the same in the considered variants. Therefore, the indicator efficiency can also be assumed to be the same.
The amount of charge at the end of filling is determined by the product of the charge density at the inlet by the filling factor ρ kη v... The use of efficient charge air coolers makes it possible to maintain the charge temperature in the intake manifold approximately constant, regardless of the degree of pressure increase in the compressor. Therefore, let us assume as a first approximation that the charge density in the intake manifold is directly proportional to the boost pressure.
In the version with standard inlet duration and closing the inlet valve after BDC, the filling ratio is 50% higher than in the version with short inlet and closing the inlet valve before BDC.
With a decrease in the filling ratio, to maintain the average indicator pressure at a given level, it is necessary to proportionally, i.e. by the same 50%, increase the boost pressure. In this case, in the variant with early closing of the inlet valve, both the pressure and the temperature of the charge at the end of filling will be 12% lower than the corresponding pressure and temperature in the variant with the closing of the inlet valve after BDC. Due to the fact that in the considered variants the actual compression ratio is the same, the pressure and temperature of the end of compression in the variant with early closing of the intake valve will also be 12% lower than when the intake valve is closed after BDC.
Thus, in an engine with a shortened intake and closing the intake valve before BDC, while maintaining the same average indicated pressure, the likelihood of knocking can be significantly reduced compared to an engine with a standard intake duration and closing of the intake valve after BDC.
Table 2 shows a comparison of the parameters of the gas engine options when operating at the nominal mode.
table 2
Gas engine options parameters
|
Option No. |
|||
|
Compression ratio ε |
|||
|
Intake valve opening φ s, ° PKV |
|||
|
Closing the intake valve φ a, ° PKV |
|||
|
Compressor pressure ratio pk |
|||
|
Pumping loss pressure pnp, MPa |
|||
|
Pressure mechanical losses pm, MPa |
|||
|
Filling factor η v |
|||
|
Indicator efficiency η i |
|||
|
Mechanical efficiency η m |
|||
|
Effective efficiency η e |
|||
|
Compression start pressure p a, MPa |
|||
|
Compression start temperature T a, K |
Figure 3 shows gas exchange diagrams for different closing angles of the intake valve and the same filling duration, and Figure 4 shows gas exchange diagrams for the same actual compression ratio and different filling duration.
At rated power mode, the intake valve closing angle φ a= 30 ° to BDC actual compression ratio ε f= 14.2 and the compressor pressure ratio π k= 2.41. This ensures a minimum level of pumping losses. With an earlier closing of the intake valve due to a decrease in the filling ratio, it is necessary to significantly increase the boost pressure by 43% (π k= 3.44), which is accompanied by a significant increase in the pressure of pumping losses.
When the intake valve is closed early, the charge temperature at the beginning of the compression stroke T a, due to its pre-expansion, is 42 K lower compared to an engine with standard intake phases.
Internal cooling of the working fluid, accompanied by the removal of part of the heat from the hottest elements of the combustion chamber, reduces the risk of detonation and glow ignition. The filling factor is reduced by one third. It becomes possible to work without detonation with a compression ratio of 15, versus 10 with a standard intake duration.
1 - φ a= 0 °; 2 - φ a= 30 °; 3 - φ a= 60 °.
Rice. 3. Diagrams of gas exchange at different angles of closing the intake valve.
1 -φ a= 30 ° to TDC; 2 -φ a= 30 ° beyond TDC.
Fig. 4. Gas exchange diagrams at the same actual compression ratio.
The time-section of the intake valves of the engine can be changed by adjusting the height of their lift. One of the possible technical solutions is the inlet valve lift control mechanism developed at SSC NAMI. The development of hydraulic drive devices for independent electronic control of valve opening and closing, based on the principles industrially implemented in accumulator batteries, has great prospects. fuel systems diesels.
Despite the increase in boost pressure and the higher compression ratio in the short intake engine, due to the early closing of the intake valve and hence the lower compression start pressure, the average cylinder pressure does not increase. Therefore, the frictional pressure also does not increase. On the other hand, with a shortened intake, the pressure of pumping losses significantly decreases (by 21%), which leads to an increase in mechanical efficiency.
The implementation of a higher compression ratio in an engine with a shortened intake causes an increase in the indicated efficiency and, in combination with a slight increase in mechanical efficiency, is accompanied by an increase in the effective efficiency by 8%.
Conclusion
The results of the studies carried out indicate that early closing of the intake valve makes it possible to manipulate the filling ratio and the actual compression ratio within a wide range, reducing the knock threshold without reducing the indicated efficiency. The shorter inlet provides an increase in mechanical efficiency by reducing the pressure of pumping losses.
Reviewers:
VF Kamenev, Doctor of Technical Sciences, Professor, Leading Expert, State Scientific Center of the Russian Federation FSUE "NAMI", Moscow.
Saykin A.M., Doctor of Technical Sciences, Head of Department, State Scientific Center of the Russian Federation FSUE "NAMI", Moscow.
Bibliographic reference
Ter-Mkrtichyan G.G. CONVERSION OF DIESEL INTO A GAS ENGINE WITH A REDUCTION OF THE ACTUAL DEGREE OF COMPRESSION // Modern problems of science and education. - 2014. - No. 5 .;URL: http://science-education.ru/ru/article/view?id=14894 (date of access: 02/01/2020). We bring to your attention the journals published by the "Academy of Natural Sciences"
It is characterized by a number of values. One of them is the compression ratio of the engine. It is important not to confuse it with compression - the value of the maximum pressure in the engine cylinder.
What is Compression Ratio
This degree is the ratio of the engine cylinder volume to the combustion chamber volume. Otherwise, we can say that the compression value is the ratio of the volume of free space above the piston when it is at the bottom dead center to the same volume when the piston is at the top point.
It was mentioned above that compression and compression ratio are not synonymous. The difference also applies to designations, if the compression is measured in atmospheres, the compression ratio is written as a certain ratio, for example, 11: 1, 10: 1, and so on. Therefore, it is impossible to say exactly what the compression ratio in the engine is measured in - this is a "dimensionless" parameter that depends on other characteristics of the internal combustion engine.
Conventionally, the compression ratio can also be described as the difference between the pressure in the chamber when the mixture is supplied (or diesel fuel in the case of diesel engines) and when a portion of fuel is ignited. This indicator depends on the model and type of engine and is due to its design. The compression ratio can be:
- high;
- low.
Compression calculation
Let's take a look at how to find out the compression ratio of an engine.
It is calculated by the formula:
Here Vр means the working volume of an individual cylinder, and Vс - the value of the volume of the combustion chamber. The formula shows the importance of the value of the volume of the chamber: if it, for example, is reduced, then the compression parameter will become larger. The same will happen in the case of an increase in the volume of the cylinder.
To find out the displacement, you need to know the cylinder diameter and piston stroke. The indicator is calculated by the formula:
Here D is the diameter and S is the piston stroke.
Illustration:
Since the combustion chamber has a complex shape, its volume is usually measured by pouring liquid into it. Knowing how much water fits into the chamber, you can determine its volume. It is convenient to use water for determination because of the specific gravity of 1 gram per cubic meter. cm - how many grams are poured, so many "cubes" in the cylinder.
An alternative way to determine the compression ratio of the engine is to refer to the documentation for it.
What does the compression ratio affect?
It is important to understand what the engine compression ratio affects: compression and power directly depend on it. If you make the compression more, the power unit will gain greater efficiency, since the specific fuel consumption will decrease.
Compression ratio gasoline engine determines the fuel with what octane number it will consume. If the fuel is low octane, this will lead to an unpleasant knock phenomenon, and too high an octane number will cause a lack of power - an engine with low compression simply cannot provide the required compression.
Table of the main ratios of compression ratios and recommended fuels for gasoline internal combustion engines:
| Compression | Petrol |
| To 10 | 92 |
| 10.5-12 | 95 |
| From 12 | 98 |
Interesting: gasoline turbocharged engines operate on fuel with a higher octane number than similar naturally aspirated internal combustion engines, so their compression ratio is higher.
Diesel engines have it even more. Since in diesel internal combustion engines high pressures develop, this parameter will also be higher for them. The optimum compression ratio for a diesel engine ranges from 18: 1 to 22: 1, depending on the unit.
Changing the compression ratio
Why change the degree?
In practice, such a need arises infrequently. You may need to change the compression:
- if desired, boost the engine;
- if you need to adapt the power unit for operation on non-standard gasoline for it, with an octane number that differs from the recommended one. This was done, for example, by Soviet car owners, since there were no kits for converting a car to gas on sale, but there was a desire to save on gasoline;
- after an unsuccessful repair, in order to eliminate the consequences of incorrect intervention. This may be thermal deformation of the cylinder head, after which milling is required. After the compression ratio of the engine has been increased by removing the metal layer, operation on the gasoline originally intended for it becomes impossible.
Sometimes the compression ratio is changed when converting cars for driving on methane fuel. Methane has an octane number of 120, which requires an increase in compression for a number of gasoline vehicles, and a decrease for diesel engines (SJ is in the range of 12-14).
Conversion of diesel to methane affects power and leads to some loss of such that can be compensated for by turbocharging. A turbocharged engine requires an additional reduction in compression ratio. Improvement of electrical and sensors, replacement of nozzles may be required diesel engine for spark plugs, a new set of cylinder-piston group.
Forcing the engine
To remove more power or to be able to drive on cheaper grades of fuel, the internal combustion engine can be boosted by changing the volume of the combustion chamber.
For additional power, the engine should be forced by increasing the compression ratio.
Important: a noticeable increase in power will be only on the engine that normally works with a lower compression ratio. So, for example, if an internal combustion engine with a 9: 1 ratio is tuned to 10: 1, it will produce more additional "horses" than an engine with a stock parameter of 12: 1, boosted to 13: 1.
Possible methods for increasing the compression ratio of the engine are as follows:
- installation of a thin cylinder head gasket and revision of the block head;
- boring of cylinders.
By reworking the cylinder head, we mean milling its lower part in contact with the block itself. The cylinder head becomes shorter, which reduces the volume of the combustion chamber and increases the compression ratio. The same happens when installing a thinner gasket.
Important: these manipulations may also require the installation of new pistons with enlarged valve recesses, since in some cases there is a risk of the piston and valves meeting. It is imperative that the valve timing is adjusted again.
The boring of the BC also leads to the installation of new pistons for the corresponding diameter. As a result, the working volume increases and the compression ratio becomes larger.
Derating for low-octane fuel
Such an operation is carried out when the issue of power is secondary, and the main task is to adapt the engine for another fuel. This is done by reducing the compression ratio, which allows the engine to run on low-octane gasoline without knocking. In addition, there are certain financial savings in the cost of fuel.
Interesting: a similar solution is often used for carburetor engines of old cars. For modern injection ICEs with electronic control, derating is highly discouraged.
The main way to reduce the compression ratio of the engine is to make the cylinder head gasket thicker. To do this, take two standard spacers, between which they make an aluminum spacer-insert. As a result, the volume of the combustion chamber and the height of the cylinder head increase.
Some interesting facts
Methanol engines racing cars have a compression ratio greater than 15: 1. In comparison, a standard carbureted engine that uses unleaded gasoline has a maximum compression ratio of 1.1: 1.
Of the serial models of engines running on gasoline with a compression of 14: 1, there are samples from Mazda (Skyactiv-G series) on the market, which are installed, for example, on the CX-5. But their actual SG is within 12, since these motors use the so-called "Atkinson cycle", when the mixture is compressed 12 times after the late closing of the valves. The efficiency of such motors is not measured by compression, but by expansion ratio.
In the middle of the 20th century, in the world engine building, especially in the USA, there was a tendency to an increase in the compression ratio. So, by the 70s, the bulk of the samples of the American automobile industry had an SD from 11 to 13: 1. But the regular operation of such internal combustion engines required the use of high-octane gasoline, which at that time could only be obtained by the ethylation process - by adding tetraethyl lead, a highly toxic component. When new environmental standards appeared in the 1970s, leaded was banned, and this led to the opposite trend - a decrease in the LF in production models of engines.
Modern engines have an automatic ignition angle control system, which allows the internal combustion engine to operate on non-native fuel - for example, 92 instead of 95, and vice versa. The UOZ control system helps to avoid detonation and other unpleasant phenomena. If it is not there, then, for example, a high-octane gasoline engine that is not designed for such fuel can lose power and even fill in the candles, since the ignition will be late. The situation can be corrected by manually setting the UOZ according to the instructions for a specific car model.
Evgeny Konstantinov
While gasoline and diesel fuel are inexorably rising in price, and all kinds of alternative power plants for vehicles remain terribly far from the people, losing to traditional internal combustion engines in price, autonomy and operating costs, the most realistic way to save money on refueling is to switch the car to a “gas diet”. At first glance, this is beneficial: the cost of converting a car will soon pay off due to the difference in the price of fuel, especially with regular commercial and passenger traffic. It is not without reason that in Moscow and many other cities a significant share of municipal vehicles has long been switched to gas. But here a logical question arises: why, then, does the share of gas-cylinder vehicles in the traffic flow both in our country and abroad do not exceed a few percent? What is the back side of a gas cylinder?
Science and Life // Illustrations
Gas station warnings are for a reason: every process gas connection is a potential location for combustible gas leaks.
Cylinders for liquefied gas are lighter, cheaper and more varied in shape than for compressed gas, and therefore they are easier to assemble based on the free space in the car and the required range.
Pay attention to the difference in the price of liquid and gaseous fuels.
Cylinders with compressed methane in the back of a tilt "Gazelle".
The reducer-evaporator in a propane system requires heating. The photo clearly shows the hose connecting the liquid heat exchanger of the gearbox to the engine cooling system.
Schematic diagram of the operation of gas equipment on a carburetor engine.
Scheme of operation of equipment for liquefied gas without converting it to the gaseous phase in an internal combustion engine with multipoint injection.
Propane-butane is stored and transported in tanks (in the photo - behind the blue gate). Thanks to such mobility, the gas station can be placed in any convenient place, and if necessary, quickly transferred to another.
The propane column is used to refuel not only cars, but also household cylinders.
A column for liquefied gas looks different from a gasoline one, but the refueling process is similar. The fuel filled in is counted in liters.
The concept of "gas vehicle fuel" includes two completely different mixtures: natural gas, in which up to 98% is methane, and propane-butane produced from associated petroleum gas. In addition to unconditional flammability, they also have a common state of aggregation at atmospheric pressure and temperatures comfortable for life. However, at low temperatures, the physical properties of these two sets of light hydrocarbons are very different. Because of this, they require completely different equipment for storage on board and supply to the engine, and in operation, cars with different gas supply systems have several significant differences.
Liquefied gas
The propane-butane mixture is well known to tourists and summer residents: it is it that is filled into household gas cylinders. It also makes up the bulk of the gas that is wastedly burned in the flares of oil producing and refining enterprises. The proportional composition of the propane-butane fuel mixture may vary. It is not so much a matter of the initial composition of the oil gas as of the temperature properties of the resulting fuel. As a motor fuel, pure butane (C 4 H 10) is good in all respects, except that it turns into a liquid state already at 0.5 ° C at atmospheric pressure. Therefore, a less caloric, but more cold-resistant propane (C 2 H 8) with a boiling point of –43 ° C is added to it. The ratio of these gases in the mixture sets the lower temperature limit for the use of fuel, which for the same reason is "summer" and "winter".
The relatively high boiling point of propane-butane, even in the "winter" version, allows it to be stored in cylinders in the form of a liquid: already under low pressure, it passes into the liquid phase. Hence another name for propane-butane fuel - liquefied gas. It is convenient and economical: the high density of the liquid phase allows you to fit a large amount of fuel in a small volume. The free space above the liquid in the cylinder is occupied by saturated steam. As the gas is consumed, the pressure in the cylinder remains constant until it is empty. Drivers of "propane" cars should fill the cylinder to a maximum of 90% when refueling in order to leave room for the steam cushion inside.
The pressure inside the cylinder primarily depends on the ambient temperature. At negative temperatures, it drops below one atmosphere, but even this is enough to maintain the system's performance. But with warming, it grows rapidly. At 20 ° C, the pressure in the cylinder is already 3-4 atmospheres, and at 50 ° C it reaches 15-16 atmospheres. For most automobile gas cylinders, these values are close to the limit. And this means that if it overheats on a hot afternoon in the southern sun, a dark car with a bottle of liquefied gas on board ... No, it will not explode, as in a Hollywood action movie, but will begin to discharge excess propane-butane into the atmosphere through a safety valve designed for just such a case. ... By the evening, when it gets colder again, the fuel in the cylinder will be noticeably less, but no one and nothing will suffer. True, as statistics show, individual lovers of additional savings on the safety valve from time to time add to the chronicle of incidents.
Compressed gas
Other principles underlie the operation of gas-cylinder equipment for machines that consume natural gas as fuel, in everyday life usually referred to as methane due to its main component. This is the same gas that is piped to city apartments. Unlike petroleum gas, methane (CH 4) has a low density (1.6 times lighter than air), and most importantly, a low boiling point. It turns into a liquid state only at –164 ° С. The presence of a small percentage of impurities of other hydrocarbons in natural gas does not greatly change the properties of pure methane. This makes it incredibly difficult to turn this gas into a liquid for use in a car. In the last decade, work has been actively carried out on the creation of so-called cryogenic tanks, which allow storing liquefied methane in a car at temperatures of –150 ° C and below and pressures up to 6 atmospheres. Prototypes of transport and filling stations were created for this fuel option. But so far this technology has not received practical distribution.
Therefore, in the overwhelming majority of cases, for use as a motor fuel, methane is simply compressed, bringing the pressure in the cylinder to 200 atmospheres. As a result, the strength and, accordingly, the mass of such a cylinder should be noticeably higher than for a propane one. And it is placed in the same volume of compressed gas significantly less than liquefied gas (in terms of moles). And this is a decrease in the autonomy of the car. Another disadvantage is the price. The significantly greater safety factor incorporated in the methane equipment results in the fact that the price of a set for a car turns out to be almost ten times higher than that of a propane equipment of a similar class.
Methane cylinders are of three standard sizes, of which passenger car only the smallest ones, 33 liters in volume, can be accommodated. But in order to provide a guaranteed cruising range of three hundred kilometers, five such cylinders are needed, with a total mass of 150 kg. It is clear that in a compact urban runabout it makes no sense to carry such a load instead of useful luggage. Therefore, there is a reason to convert only large cars to methane. First of all, trucks and buses.
With all this, methane has two significant advantages over petroleum gas. First, it is even cheaper and is not tied to the oil price. And secondly, methane equipment is structurally insured against problems with winter operation and allows, if desired, to do without gasoline at all. In the case of propane-butane in our climatic conditions, such a focus will not work. The car will in fact remain dual-fuel. The reason is precisely the liquefaction of gas. More precisely, in the process of active evaporation, the gas is sharply cooled. As a result, the temperature in the cylinder and especially in the gas reducer drops sharply. To prevent the equipment from freezing, the gearbox is heated by building in a heat exchanger connected to the engine cooling system. But for this system to start working, the liquid in the line must be preheated. Therefore, it is recommended to start and warm up the engine at an ambient temperature below 10 ° C strictly on gasoline. And only then, when the engine reaches operating temperature, switch to gas. However, modern electronic systems switch everything on their own, without the help of a driver, automatically controlling the temperature and preventing the equipment from freezing. True, to maintain the correct operation of the electronics in these systems, you cannot empty the gas tank dry, even in hot weather. The starting mode on gas is emergency for such equipment, and the system can be switched to it only forcibly in case of emergency.
The methane equipment has no difficulties with the winter start-up. On the contrary, it is even easier to start the engine on this gas in cold weather than on gasoline. The absence of a liquid phase does not require heating the reducer, which only reduces the pressure in the system from 200 transport atmospheres to one working atmosphere.
The wonders of direct injection
The most difficult thing is to convert to gas modern engines with direct fuel injection into the cylinders. The reason is that gas injectors are traditionally located in the intake tract, where mixture formation occurs in all other types of internal combustion engines without direct injection. But the presence of such completely negates the possibility of adding gas power so easily and technologically. Firstly, ideally, gas should also be fed directly into the cylinder, and secondly, and more importantly, liquid fuel serves to cool its own direct injection injectors. Without it, they very quickly fail from overheating.
There are options for solving this problem, and at least two. The first turns the engine into a dual-fuel one. It was invented quite a long time ago, even before the advent of direct injection on gasoline engines and was proposed for adapting diesel engines to work on methane. The gas does not ignite from compression, and therefore the "carbonated diesel" starts up on diesel fuel and continues to work on it in the mode idle speed and minimum load. And then gas comes into play. It is due to its supply that the crankshaft rotation speed is regulated in the mode of medium and high revolutions. For this injection pump ( fuel pump high pressure) limit the supply of liquid fuel to 25-30% of the nominal. Methane enters the engine through its own line bypassing the high-pressure fuel pump. There are no problems with its lubrication due to a decrease in the supply of diesel fuel at high speeds. In this case, the diesel injectors continue to be cooled by the fuel passing through them. True, the heat load on them in the high speed mode still remains increased.
A similar power supply scheme began to be used for gasoline engines with direct injection. Moreover, it works with both methane and propane-butane equipment. But in the latter case, an alternative solution that has appeared quite recently is considered more promising. It all started with the idea of abandoning the traditional gearbox with an evaporator and supplying propane-butane to the engine under pressure in the liquid phase. The next steps were the abandonment of gas injectors and the supply of liquefied gas through standard gasoline injectors. An electronic matching module was added to the circuit, connecting a gas or petrol line according to the situation. Wherein new system lost the traditional problems with a cold start on gas: no evaporation - no cooling. True, the cost of equipment for engines with direct injection in both cases is such that it pays off only with very high mileage.
By the way, the economic feasibility limits the use of LPG equipment in diesel engines. It is for reasons of benefit that only methane equipment is used for compression-ignition engines, moreover, suitable in terms of characteristics only for heavy equipment engines equipped with traditional high-pressure fuel pumps. The fact is that the transfer of small economical passenger engines from diesel to gas does not pay off, but the development and technical implementation of gas equipment for the latest engines with a common fuel rail ( common rail) are considered economically unjustified at present.
True, there is another, alternative way of converting a diesel engine to gas - by full conversion into a gas engine with spark ignition... In such an engine, the compression ratio decreases to 10-11 units, candles and high-voltage electrics appear, and it says goodbye to diesel fuel forever. But it starts to consume gasoline painlessly.
Working conditions
Old Soviet guidelines for converting gasoline vehicles to gas required grinding the cylinder heads (cylinder head) to raise the compression ratio. This is understandable: the objects of gasification in them were power units commercial vehicles running on gasoline with an octane rating of 76 and below. Methane has an octane number of 117, while propane-butane mixtures have about a hundred. Thus, both gas fuels are significantly less prone to knocking than gasoline, and allow the engine compression ratio to be raised to optimize the combustion process.
In addition, for archaic carburetor engines equipped with mechanical gas supply systems, an increase in the compression ratio made it possible to compensate for the loss of power that occurred when switching to gas. The fact is that gasoline and gases are mixed with air in the intake tract in completely different proportions, which is why when using propane-butane, and especially methane, the engine has to run on a much leaner mixture. As a result - a decrease in engine torque, leading to a drop in power by 5-7% in the first case and by 18-20% in the second. At the same time, on the graph of the external speed characteristic, the shape of the torque curve for each specific motor remains unchanged. It simply shifts downward along the "axis of newton meters."
However, for engines with electronic systems injection, equipped with modern gas supply systems, all these recommendations and figures have almost no practical value. Because, firstly, their compression ratio is already sufficient, and even for the transition to methane, work on grinding the cylinder head is completely unjustified economically. And secondly, the gas equipment processor, coordinated with the car electronics, organizes the fuel supply in such a way that it compensates at least half of the aforementioned failure in torque. In systems with direct injection and in gas-diesel engines, gas fuel in certain speed ranges is even capable of raising torque.
In addition, the electronics clearly monitors the required ignition timing, which, when switching to gas, should be greater than for gasoline, all other things being equal. Gas fuel burns more slowly, which means that it needs to be ignited earlier. For the same reason, the thermal load on the valves and their seats increases. On the other hand, the shock load on the cylinder-piston group becomes less. In addition, a winter start-up on methane is much more useful for her than on gasoline: gas does not wash oil from the cylinder walls. And in general, gas fuel does not contain catalysts for aging metals; more complete combustion of the fuel reduces the toxicity of the exhaust and carbon deposits in the cylinders.
Autonomous swimming
Perhaps the most notable disadvantage in gas car becomes its limited autonomy. First, the consumption of gas fuel, if we count by volume, turns out to be more than gasoline and even more diesel fuel. And secondly, the gas car is tied to the corresponding gas stations. Otherwise, the meaning of its transfer to an alternative fuel begins to tend to zero. Especially difficult for those who use methane gas. There are very few methane gas stations, and all of them are tied to main gas pipelines. They are just small compressor stations on the branches of the main pipe. In the late 80s - early 90s of the twentieth century, our country tried to actively convert transport to methane within the framework of the state program. It was then that the majority of methane filling stations appeared. By 1993, 368 of them had been built, and since then this number, if it has grown, is quite insignificant. Most gas stations are located in the European part of the country near federal highways and cities. But at the same time, their location was determined not so much from the point of view of the convenience of motorists as from the point of view of gas workers. Therefore, only in very rare cases did gas stations turn out directly to highways and almost never inside megalopolises. Almost everywhere, in order to refuel with methane, you need to make a detour for several kilometers to some industrial zone. Therefore, when planning a long-distance route, these gas stations must be looked for and memorized in advance. The only thing that is convenient in such a situation is the consistently high quality of fuel at any of the methane stations. Gas from the main gas pipeline is very problematic to dilute or spoil. Unless a filter or drying system at one of these filling stations can suddenly fail.
Propane-butane can be transported in tanks, and due to this property, the geography of refueling for it is much wider. In some regions, they can be refueled even in the farthest backwoods. But it will not hurt to study the presence of propane gas stations on the upcoming route, so that their sudden absence on the highway does not become an unpleasant surprise. At the same time, liquefied gas always leaves a fraction of the risk of getting on fuel out of season or simply of poor quality.
A fully methane diesel engine will save up to 60% from the amount of ordinary costs and of course to significantly reduce environmental pollution.
We can convert almost any diesel engine to use methane as a gas motor fuel.
Don't wait tomorrow, start saving today!
How can a diesel engine run on methane?
A diesel engine is an engine in which fuel is ignited by heating from compression. A standard diesel engine cannot run on gas fuel because methane has a significantly higher flash point than diesel fuel (diesel fuel - 300-330 C, methane - 650 C), which cannot be achieved with the compression ratios used in diesel engines.
The second reason why a diesel engine will not be able to run on gas fuel is the detonation phenomenon, i.e. non-standard (explosive combustion of fuel, which occurs when the compression ratio is excessive. For diesel engines, the compression ratio of the fuel-air mixture is 14-22 times, the methane engine can have a compression ratio of up to 12-16 times.
Therefore, to transfer a diesel engine to gas engine mode, you need to do two main things:
- Reduce engine compression ratio
- Install spark ignition system
After these modifications, your engine will only run on methane. Return to diesel mode is possible only after special work has been carried out.
For more details on the essence of the work performed, see the section "How exactly is the conversion of diesel to methane"
How much savings can I get?
The amount of your savings is calculated as the difference between the cost per 100 km of run on diesel fuel before the conversion of the engine and the cost of purchasing gas fuel.
For example, for the Freigtleiner Cascadia truck, the average diesel consumption was 35 liters per 100 km, and after conversion to run on methane, the gas consumption was 42 Nm3. methane. Then, with the cost of diesel fuel at 31 rubles, 100 km. mileage initially cost 1085 rubles, and after conversion at a methane cost of 11 rubles per normal cubic meter (nm3), 100 km of run cost 462 rubles.
The savings amounted to 623 rubles per 100 kilometers, or 57%. Taking into account the annual mileage of 100,000 km, the annual savings amounted to 623,000 rubles. The cost of installing propane on this machine was 600,000 rubles. Thus, the payback period of the system was approximately 11 months.
Also, an additional advantage of methane as a gas engine fuel is that it is extremely difficult to steal and practically impossible to "drain", since under normal conditions it is gas. For the same reasons, it cannot be sold.
The methane consumption after the conversion of the diesel engine to the gas engine mode can vary from 1.05 to 1.25 nm3 of methane per liter of diesel fuel consumption (depending on the design of the diesel engine, its deterioration, etc.).
You can read examples from our experience on the consumption of methane by our converted diesels.
On average, for preliminary calculations, a diesel engine operating on methane will consume gas engine fuel at the rate of 1 liter of diesel fuel consumption in diesel mode = 1.2 nm3 of methane in gas engine mode.You can get specific savings values for your car by filling out an application for conversion by clicking the red button at the end of this page.
Where can I get methane gas?
In the CIS countries, there are over 500 CNG stations, and Russia has more than 240 CNG filling stations.
You can view up-to-date information on the location and opening hours of the CNG filling station on the interactive map below. Map courtesy of gazmap.ru
And if there is a gas pipe next to your vehicle fleet, then it makes sense to consider options for building your own CNG filling station.
Just call us and we will be happy to advise you on all options.
What is the mileage for one methane filling?
Methane is stored on board a car in a gaseous state under a high pressure of 200 atmospheres in special cylinders. The large weight and size of these cylinders is a significant negative factor limiting the use of methane as a gas motor fuel.
LLC "RAGSK" use in its work high-quality metal-plastic composite cylinders (Type-2), certified for use in the Russian Federation.
The inside of these cylinders is made of high-strength chromium-molybdenum steel, while the outside is wrapped in fiberglass and filled with epoxy resin.
To store 1 Nm3 of methane, 5 liters of the hydraulic volume of the cylinder are required, i.e. for example, a 100 liter cylinder allows you to store about 20 nm3 of methane (in fact, a little more, due to the fact that methane is not an ideal gas and is better compressed). The weight of 1 liter of hydraulic unit is approximately 0.85 kg, i.e. the weight of the storage system for 20 nm3 of methane will be approximately 100 kg (85 kg is the weight of the cylinder and 15 kg is the weight of the methane itself).
Type-2 cylinders for methane storage look like this:
The complete methane storage system looks like this:
In practice, it is usually possible to achieve the following mileage values:
- 200-250 km - for minibuses. Storage system weight - 250 kg
- 250-300 km - for medium-sized city buses. Storage system weight - 450 kg
- 500 km - for truck tractors... Storage system weight - 900 kg
You can get specific values of methane-powered mileage for your car by filling out an application for conversion by pressing the red button at the end of this page.
How exactly is the conversion of diesel to methane carried out?
Converting a diesel engine to gas mode will require serious intervention in the engine itself.
First we have to change the compression ratio (why? See the section "How can a diesel engine run on methane?") We use various methods to do this, choosing the best one for your engine:
- Piston milling
- Cylinder head gasket
- Installing new pistons
- Shortening the connecting rod
In most cases, we use piston milling (see illustration above).
This is what the pistons will look like after milling:
We also install a number of additional sensors and devices ( electronic pedal gas, crankshaft position sensor, oxygen amount sensor, knock sensor, etc.).
All system components are controlled by an electronic control unit (ECU).
Something like this will look like a set of components for installation on the engine:
Will engine performance change when running on methane?
Power There is a widespread opinion that the engine loses power up to 25% on methane. This opinion is true for dual-fuel "gasoline-gas" engines and partly true for naturally aspirated diesel engines.For modern engines equipped with an inflator, this opinion is erroneous.
The high strength resource of the original diesel engine, designed to work with a compression ratio of 16-22 times and the high octane number of gas fuel, allow us to use the compression ratio 12-14 times. Such a high compression ratio allows obtaining the same (and even large) power density working on stoichiometric fuel mixtures. However, at the same time, it is not possible to meet the toxicity standards higher than EURO-3, and the thermal stress of the converted engine also increases.
Modern inflatable diesel engines (especially those with intercooling of inflatable air) make it possible to operate on significantly lean mixtures while maintaining the power of the original diesel engine, keeping the thermal regime within the previous limits and keeping within the EURO-4 toxicity standards.
For naturally aspirated diesel engines, we offer 2 alternatives: either reducing the operating power by 10-15% or using a water injection system in the intake manifold in order to maintain an acceptable operating temperature and achieve EURO-4 emission standards
Typical dependences of power on engine speed, by fuel type:
A radical solution to the problem of displacement of the peak torque for a gas engine is to replace the turbine with an oversized turbine of a special type with a bypass solenoid valve at high speeds. However, the high cost of such a solution does not give us the opportunity to use it for individual conversion.
Reliability Engine life will increase significantly. Since gas combustion occurs more evenly than diesel fuel, the compression ratio of a gas engine is less than that of a diesel one and the gas does not contain foreign impurities, unlike diesel fuel. Oil Gas engines are more demanding in terms of oil quality. We recommend using high-quality multigrade oils of SAE 15W-40, 10W-40 grades and changing the oil at least 10,000 km.If possible, it is advisable to use special oils, such as LUKOIL EFFORSE 4004 or Shell Mysella LA SAE 40. This is not necessary, but with them the engine will last a very long time.
Due to the high water content in the combustion products of gas-air mixtures in gas engines, water resistance problems can arise. engine oils Also, gas engines are more sensitive to ash deposits in the combustion chamber. Therefore, the sulphated ash content of gas engine oils is limited to lower values, and the requirements for the hydrophobicity of the oil are increased.
Noise You will be very surprised! A gas engine is a very quiet machine compared to a diesel one. The noise level will decrease by 10-15 dB for instruments, which corresponds to 2-3 quieter operation for subjective sensations.Of course, no one cares about the environment. But anyway… ?
The methane gas engine is significantly superior in all environmental characteristics to an engine of the same power operating on diesel fuel and is second only to electric and hydrogen engines in terms of emissions.
This is especially noticeable for such an important indicator for large cities as smokiness. All townspeople are pretty annoyed by the smoky tails behind the LIAZs. This will not happen on methane, so there is no soot formation during gas combustion!
As a rule, the environmental class for a methane engine is Euro-4 (without the use of urea or a gas recirculation system). However, with the installation of an additional catalyst, the environmental class can be raised to the Euro-5 level.
ENGINEERING
UDC 62l.43.052
TECHNICAL IMPLEMENTATION OF CHANGING THE COMPRESSION RATES OF A SMALL ENGINE THAT RUNS ON NATURAL GAS
F.I. Abramchuk, professor, doctor of technical sciences, A.N. Kabanov, associate professor, candidate of technical sciences,
A.P. Kuzmenko, postgraduate student, KhNADU
Annotation. The results of the technical implementation of changing the compression ratio on the MeMZ-307 engine, which has been re-equipped to run on natural gas, are presented.
Key words: compression ratio, car engine, natural gas.
TECHNICAL REALIZATION OF THE ZMINI STEP OF STISKANNYA LITTLE AUTOMOBILE ENGINE,
SCHO PRATSYUЄ ON NATURAL GASI
F.І. Abramchuk, professor, doctor of technical sciences, O.M. Kabanov, associate professor, candidate of technical sciences,
A.P. Kuzmenko, postgraduate student, KhNADU
Abstract. The results of the technical implementation of the step change for the MeMZ-307 engine, re-equipment for the robot using natural gas have been introduced.
Key words: steps of squeezing, motor vehicle, natural gas.
TECHNICAL REALIZATION OF COMPRESSION RATIO VARIATION OF SMALL-CAPACITY AUTOMOTIVE NATURAL GAS POWERED ENGINE
F. Abramchuk, Professor, Doctor of Technical Science, A. Kabanov, Associate Professor, Doctor of Technical Science, A. Kuzmenko, postgraduate, KhNAHU
Abstract. The results of technical realization of compression ratio variation of MeMZ-3Q7 engine converted for natural gas running are given.
Key words: compression ratio, automotive engine, natural gas.
Introduction
The development and successful operation of pure gas engines that run on natural gas depend on the right choice the main parameters of the working process that determine their technical, economic and environmental characteristics. First of all, this concerns the choice of the compression ratio.
Natural gas, having a high octane number (110-130), allows an increase in the compression ratio. Maximum degree value
compression, excluding detonation, can be chosen in a first approximation by calculation. However, it is possible to check and refine the calculated data only experimentally.
Analysis of publications
When converting the petrol engine (Vh = 1 l) of the VW POLO car to natural gas, the shape of the piston fire surface was simplified. Reducing the volume of the compression chamber increased the compression ratio from 10.7 to 13.5.
On the D21A engine, the piston was reworked to reduce the compression ratio from 16.5 to 9.5. The combustion chamber of a hemispherical type for a diesel engine has been modified for the working process of a spark ignition gas engine.
When converting a YaMZ-236 diesel engine into a gas engine, the compression ratio from 16.2 to 12 was also reduced due to additional processing of the piston.
Purpose and problem statement
The aim of the work is to develop the design of the combustion chamber parts of the MeMZ-307 engine, which will provide the compression ratio e = 12 and e = 14 for experimental research.
Choosing an approach to changing the compression ratio
For a small-displacement gasoline engine convertible to gas, a change in the compression ratio means an increase in comparison with the base ICE. There are several ways to accomplish this task.
Ideally, it is desirable to install a system for changing the compression ratio on the engine, which makes it possible to perform this task in real time, including without interrupting the operation of the engine. However, such systems are very expensive and complex in design and operation, require significant design changes, and are also an element of engine unreliability.
You can also change the compression ratio by increasing the number or thickness of the gaskets between the head and the cylinder block. This method is cheap, but it increases the likelihood of burning out the gaskets if the normal combustion process is disturbed. In addition, this method of regulating the compression ratio is characterized by low accuracy, since the value of e will depend on the tightening force of the nuts on the head studs and the quality of the gaskets. Most often, this method is used to lower the compression ratio.
The use of linings for pistons is technically difficult, since there is a problem of reliable attachment of a relatively thin liner (about 1 mm) to the piston and reliable operation of this attachment in a combustion chamber.
The best option is the manufacture of sets of pistons, each of which provides a given compression ratio. This method requires partial disassembly of the engine to change the compression ratio, however, it provides a sufficiently high accuracy of the value of e in the experiment and the reliability of the engine with a changed compression ratio (the strength and reliability of the engine's structural elements does not decrease). Moreover, this method is relatively cheap.
Research results
The essence of the problem was to use positive traits natural gas (high octane number) and the peculiarities of mixture formation, to compensate for the loss of power when the engine is running on this fuel. To accomplish this task, it was decided to change the compression ratio.
According to the experimental plan, the compression ratio should vary from e = 9.8 (standard equipment) to e = 14. It is advisable to choose an intermediate value of the compression ratio e = 12 (as the arithmetic mean of the extreme values of e). If necessary, it is possible to manufacture sets of pistons providing other intermediate values of the compression ratio.
For the technical implementation of the specified compression ratios, calculations, design developments and experimentally verified volumes of compression chambers were performed using the pouring method. Spill results are shown in Tables 1 and 2.
Table 1 Results of pouring the combustion chamber in the cylinder head
1 cyl. 2 cyl. 3 cyl. 4 cyl.
22,78 22,81 22,79 22,79
Table 2 The results of pouring the combustion chamber in the pistons (the piston is installed in the cylinder)
1 cyl. 2 cyl. 3 cyl. 4 cyl.
9,7 9,68 9,71 9,69
The compressed thickness of the gasket is 1 mm. The sinking of the piston relative to the plane of the cylinder block is 0.5 mm, which was determined by measurements.
Accordingly, the volume of the combustion chamber Vs will consist of the volume in the cylinder head Vn, the volume in the piston Vn and the volume of the gap between the piston and the cylinder head (piston retraction relative to the plane of the cylinder block + gasket thickness) Vv = 6.6 cm3.
Us = 22.79 + 9.7 + 4.4 = 36.89 (cm3).
It was decided to change the compression ratio by changing the volume of the combustion chamber by changing the geometry of the piston head, since this method allows all variants of the compression ratio to be implemented, and at the same time it is possible to return to the standard configuration.
In fig. 1 shows a serial complete set of parts of the combustion chamber with volumes in the piston Yn = 7.5 cm3.
Rice. 1. Serial complete set of combustion chamber parts Us = 36.9 cm3 (e = 9.8)
To obtain the compression ratio e = 12, it is sufficient to complete the combustion chamber with a flat-bottomed piston, in which two small samples are made with a total volume
0.1 cm3, preventing the intake and exhaust valves from meeting the piston during
overlap. In this case, the volume of the compression chamber is
Us = 36.9 - 7.4 = 29.5 (cm3).
In this case, the clearance between the piston and the cylinder head remains 8 = 1.5 mm. The design of the combustion chamber providing є = 12 is shown in Fig. 2.
Rice. 2. Completion of parts of the combustion chamber of a gas engine to obtain a compression ratio є = 12 (Us = 29.5 m3)
It is accepted to realize the compression ratio є = 14 by increasing the height of the piston with a flat bottom by I = 1 mm. In this case, the piston also has two valve recesses with a total volume of 0.2 cm3. The volume of the compression chamber is reduced by
ДУ = - И =. 0.1 = 4.42 (cm3).
Such a complete set of parts of the combustion chamber gives a volume
Us = 29.4 - 4.22 = 25.18 (cm3).
In fig. 3 shows the configuration of the combustion chamber, providing a compression ratio є = 13.9.
The clearance between the piston fire surface and the cylinder head is 0.5 mm, which is sufficient for normal operation of the parts.
Rice. 3. Components of the combustion chamber of a gas engine with e = 13.9 (Us = 25.18 cm3)
1. Simplification of the geometric shape of the piston fire surface (flat head with two small recesses) made it possible to increase the compression ratio from 9.8 to 12.
2. Reducing the clearance to 5 = 0.5 mm between the cylinder head and the piston at TDC and simplifying the geometric shape of the fire
the piston surface allowed to increase є to 13.9 units.
Literature
1. Based on materials from the site: www.empa.ch
2. Bgantsev V.N. Gas engine based
of a four-stroke general-purpose diesel engine / V.N. Bgantsev, A.M. Levterov,
B.P. Marakhovsky // World of technology and technology. - 2003. - No. 10. - S. 74-75.
3. Zakharchuk V.I. Rozrakhunkovo-eksperimen-
more up to date of gas engine, re-equipped with diesel engine / V.I. Zakharchuk, O. V. Sitovskiy, I.S. Kozachuk // Automobile transport: collection of articles. scientific. tr. -Kharkiv: HNADU. - 2005. - Issue. 16. -
4. Bogomolov V.A. Design features
an experimental setup for researching a gas engine 64 13/14 with spark ignition / V.A. Bogomolov, F.I. Abramchuk, V.M. Ma-noylo et al. // Bulletin of the KhNADU: collection of articles. scientific. tr. - Kharkiv: HNADU. -2007. - No. 37. - S. 43-47.
Reviewer: M. A. Podrigalo, professor, doctor of technical sciences, KhNADU.
