MPI engines are gradually becoming a thing of the past, so it is less and less common to meet a car enthusiast who understands what it is about when they call this abbreviation. Those who have changed a lot of cars or are interested in cars in general know about it.
Having replaced carburetor engines, becoming the next step in the development of the automotive industry, this type of engine is now giving way to advanced developments. Today, many people think in advance which engine should be on a personal car: TSI, FSI or MPI. Although, until now, many experts consider the latter the most practical, reliable and trouble-free in the family of injection engines.
FSI is considered a more modern development, the next step after MPI. The BSE engine appeared in 2005 and is famous for being well tolerated by the poor quality of domestic fuel.
Did you know? The abbreviation MPI comes from the term Multi Point Injection, which means multipoint fuel injection. The motor was actively used at the Volkswagen concern. It was gradually introduced at the Skoda subsidiary. The motors were also installed there for the last time - on the Yeti and Octavia models.
It should also be explained what MPI and TSI are. If the first term means an internal combustion engine, in which each cylinder has its own injector, then TSI has different interpretations.
So, initially, the abbreviation meant double supercharging and stratified injection: Twincharged Stratified Injection. But recently, the abbreviation TFSI has become increasingly used, in which the additional letter F stands for Fuel - fuel.
You can often find another abbreviated name of the engine - MPI DOHC, which means it is easy to understand if you know that the term DOHC refers to engines in which there are 2 camshafts and 4 valves in the cylinder head.
Principle of operation
The MPI fuel injection system delivers fuel from multiple points simultaneously. Each cylinder has its own injector, and fuel is supplied through a dedicated exhaust channel. But what distinguishes the MPI engine from the TSI, which is also equipped with a multi-point fuel supply, is lack of pressurization.
The fuel mixture is supplied to the cylinders not with the help of turbochargers, but with the help of a gas pump. It pumps gasoline into a special intake manifold under pressure of three atmospheres, where it mixes with air and is also sucked into the cylinder through the intake valve under pressure.
Schematically, the engine looks like this:- The fuel pump pumps fuel from the tank to the injector.
- A signal is sent from the electronic injection control unit to the injector, which passes fuel into a special channel.
- The mixture is directed to the combustion chamber.
The hydraulic drive control system consists of a clutch with a grease fitting and a system that limits trims. It includes rubber mounts that can independently adjust to the engine operating mode, reducing noise and vibration during operation. The engine has 8 valves: 2 for each of the cylinders, as well as a camshaft.
Did you know? The most common engines are the MPI 1.4 with 80 horsepower and 1.6 with 105 horsepower. But automakers are still gradually abandoning them. The only ones who still use engines of this type are the Dodge and Skoda companies.
Dignity
The engine has several advantages, the main of which is - simplicity of the system. This makes it easy to repair and maintain. For repairs, it is not always necessary to completely disassemble the entire structure. It can run on 92 gasoline.
In addition, its overall construction is very robust. In most cases, you can drive up to 300 thousand km without repairing the engine. Of course, if you maintain it properly: change the oil and filters on time.
disadvantages
However, it was the design features of the MPI engine that provoked its shortcomings. The intake system has very limited capabilities, since the fuel is combined with air not in the cylinders, but in the channels. Therefore, the motor has a weak torque and low power. In addition, 8 valves are considered insufficient for today's vehicles.
In general, this type of engine is only good for a low-speed family car. Apparently, therefore, car manufacturers have been increasingly abandoning it lately.
Important! Today, only a few companies use this type of motor in their vehicles. In addition, repairing it is quite expensive. This must be taken into account when choosing a car.
Although there are attempts to upgrade this engine. For example, in 2014 Skoda installed an improved engine of this type on the Yeti, designed specifically for the Russian segment. He received a power of 110 horsepower.
American developers are also engaged in modernization, but nevertheless, in the confrontation between power and reliability, manufacturers and motorists more often choose the former.
MPI engine in Volkswagen cars: principle of operation, features, advantages and disadvantages. The MPI engine is an injection design using a multi-point fuel injection device. Therefore, this motor received the corresponding name "Multi-Point-Injection". In other words, each engine cylinder has its own injector-injector. This very scheme was implemented by the Volkswagen carmaker.
This type of engine is installed on the Volkswagen New Polo sedan, some configurations of the Golf and (some of the Golf and Jetta are also equipped with TSI engines). On the Passat SS, only TSI engines are installed now (2016). FSI is installed.
The MPI engine is the most outdated of the entire Volkswagen engine range. But, nevertheless, it is distinguished by excellent practicality and reliability. Some experts note that now this type of engine does not meet the current requirements in terms of efficiency and environmental friendliness. Moreover, until recently it could be argued that this type of motor was taken out of production. And the last automobile model of the automaker where it was used was the Skoda Oktavia of the 2nd series.
But suddenly the MPI engine was revived and became in demand again. In the fall of 2015, Volkswagen launched a production line of motors at its Kaluga plant, where they began to produce the MPI 1.6 engine structure of the EA211 series.
Features of the MPI engine
The main difference between such engines has already been written - this is a multi-point gasoline supply. But those who are good with car engines may note that TSI engines also have multipoint injection.
Therefore, we move on to another distinctive feature - there is no supercharging in the MPI. Those. there are no turbochargers to force the fuel mixture into the cylinders. An ordinary gasoline pump that supplies fuel under three atmospheres pressure to a special intake manifold, where it is further mixed with the air mass and drawn through the intake valve directly into the cylinder. As you can see, this is quite similar to the activity of a carburetor engine. There is no direct fuel injection into the cylinder, as in FSI, GDi or TSI devices.
Another feature is the presence of a water system, thanks to which the fuel mixture is cooled. This is due to the fact that an increased temperature regime is established in the area of the cylinder head, and the flow of gasoline is carried out under a rather low pressure. Therefore, all this can boil and form gas air locks.
Advantages
The MPI engine is distinguished by its own unpretentiousness to fuel quality and can operate on 92nd gasoline.
By its design, this motor is very durable, and its smallest mileage without any repair work, as the manufacturer informs, is 300 thousand km, of course, if the oils and filters are changed on time.
Due to its not very complex design, the MPI engine can be easily and inexpensively repaired in the event of a breakdown and, in general, this significantly affects its price. The conventional design compares favorably with the TSI, which has a high pressure pump and turbocharger. The MPI engine is also less prone to overheating.
Another advantage of the motor is the presence of rubber mounts located directly under the engine. This significantly reduces noise and jitter while driving.
disadvantages
It can be noted that the MPI engine is not very dynamic. Due to the fact that the process of fuel mixing is carried out in special exhaust ports (before the fuel enters the cylinders), such motors are considered limited. An eight-valve system with a timing set speaks of shortcomings in power. Thus, they are designed for not very fast travel.
The disadvantages include the fact that MPI is less economical. Multipoint injection is inferior in efficiency to supercharging along with direct fuel injection into the cylinder, as is done in the TSI propulsion system.
And yet, if you add up the advantages and disadvantages, it turns out that these engines are quite comparable in terms of competitiveness, especially for Russian roads. It is no coincidence that German manufacturers have abandoned the 1.2-liter TSI engine for the Skoda Yeti, opting for the tried-and-true 1.6-liter MPI engine.
Automakers are constantly upgrading their engines to maximize efficiency while minimizing fuel consumption and minimizing damage to engine components. Drivers who are not particularly interested in motor construction can hardly tell exactly what an MPI engine is and how it differs from other motors. Despite the fact that manufacturers are already abandoning such engines in the mass automotive segment, it is important to know what are good and bad about such engines.
If you ask an ordinary motorist about the motors that he knows, for sure, he will name the TSI and FSI engines. These engines are now more common than MPIs, but these three are injection engines.
The abbreviation MPI itself stands for Multi Point Injection, that is, multi-point fuel injection. The development and implementation of the MPI motor was carried out by the Volkswagen concern. It can be found on old models of Skoda Yeti and Skoda Octavia cars.
Please note: The abbreviation MPI DOHC can be found in various technical documentation. This type of engine has 2 camshafts and 4 valves in the cylinder head.
How the MPI engine works
In the MPI motor, as can be understood from the decoding of the abbreviation, multipoint simultaneous injection is used. That is, the fuel supply occurs at one moment from several points at once.
Each cylinder in the MPI engine has its own injector, and fuel is supplied through a separate exhaust port using a petrol pump. Fuel enters the dedicated intake manifold under a pressure of about 3 atmospheres. In the manifold, the process of creating a fuel-air mixture takes place, that is, mixing with air, after which the resulting mixture under pressure goes into the cylinder through the intake valve.
Important: The main difference between the MPI engine and the TSI is that the first has no turbocharging.
If we disassemble the operation of the MPI engine step by step, we can distinguish 3 main stages:
- At the first stage, fuel flows into the injector from the tank through the fuel pump;
- At the second stage, the fuel enters a special channel after a special command to the injector from the electronic control unit;
- At the final stage, the resulting air-fuel mixture is sent to the combustion chamber.
It should be noted that according to MPI technology, the most common engines with a volume of 1.4 liters and 80 hp. and a volume of 1.6 liters for 105 hp, they can be found on Skoda cars.
Please note: Since the ignition timing is assumed in the MPI engine, the gas pedal is extremely sensitive.
Advantages of MPI engines
As noted above, now manufacturers have begun to abandon motors made using MPI technology. Nevertheless, they have a number of characteristic advantages for which drivers value them:
- Reliability. The MPI motor is able to “cover” more than 300 thousand kilometers if you follow it, that is, change filters and oils in a timely manner. The design of the engine itself is quite sturdy;
- Simplicity. The MPI engine is simpler than TSI and FSI. Accordingly, it is easier to maintain;
- Profitability. The MPI engine runs well, including 92 gasoline.
The forthcoming publication is intended for experienced drivers who have changed a lot of vehicles. Today, an engine labeled MPI is considered a kind of rarity, supplanted by more advanced innovative developments. And at one time, such a power unit was a novelty of advanced technologies.
The information provided will help you better understand the device of this motor, weigh its disadvantages and evaluate its advantages. Also in this article you can find a detailed description of the principle of operation of the complex mechanism with the MPI index.
What was good about the MPI engine, memories of achievements in the field of automotive industry
Some confirmation of the well-known statement that nothing lasts forever in our ghostly world is the gradually disappearing popularity of the power unit with the MPI marking. At one time, it was considered a very successful replacement for carburetor engines, a definite innovation in the modern automotive industry, an advanced stage in its development.
Today, most motorists look at each other in bewilderment at the mention of the abbreviation MPI, since contemporaries are more familiar with the TSI, FSI engines or the BSE that appeared in 2005. It should be noted that the latest engine model is characterized by excellent portability of domestic fuel, whose quality leaves much to be desired.
In the line of injection engines, the unit in question occupies a worthy place, characterized by extreme practicality, reliability and reliability. At the time of its launch into production, it was considered the forefront of the domestic automotive industry.
Than the drivers with considerable experience remembered the MPI injection engine. What are the features of its principle of operation, what are the indisputable advantages and annoying flaws. Further information will answer the questions of curious motorists.
The principle of operation of the MPI power plant
First, you need to explain to uninformed readers that the abbreviation MPI stands for an internal combustion engine, each cylinder of which corresponds to a separate injector. The name MPI DOHC is much more common. Here the second part of the name indicates two camshafts with four valves.
The principle of operation of the main mechanisms that make the MPI engine function is quite simple. Nevertheless, it deserves a separate consideration.
Fuel is supplied simultaneously from several points. As mentioned earlier, there is a separate injector for each cylinder and a dedicated exhaust port for fuel delivery. The multi-point fuel supply is also characteristic of the TSI engine, but it differs in the presence of pressurization, which is absent in the engine in question.
A special intake manifold is an intermediate link, where fuel is supplied under a pressure of three atmospheres by a special pump. A mixture of gasoline and air is formed in it, after which it enters the cylinders through the intake valve. The whole process is carried out at elevated pressure.
Briefly, the operation of the engine can be described in three stages:
- First, the fuel from the gas tank is pumped to the injector;
- After receiving a certain signal from the electronic control unit, the injector directs the fuel into a special channel;
- In this direction, the fuel mixture is delivered to the combustion chamber.
Some similarity in the principle of operation with the carburetor unit is leveled by the presence of a liquid cooling system. This is due to the excessive overheating of the space at the cylinder head.
A strong increase in temperature can cause the fuel that is there under low pressure to boil. The gases emitted during this process can form undesirable gas-air locks.
Another distinguishing feature of the MPI engine is the presence of a specific control mechanism for the hydraulic drive, consisting of a clutch equipped with a grease nipple, and a special system that sets certain limits for trims.
It is usually represented by rubber supports, a distinctive feature of which is the ability to independently adapt to the mode of operation of the power unit. Their main purpose is considered to be noise and vibration reduction during engine operation.
The design of the MPI engine also includes eight valves, located in pairs on each of the four cylinders. An important part of such an engine is the camshaft, which is considered an essential part of the system.
Advantages and disadvantages of MPI motors
First of all, it should be noted the undeniable advantages of the design of the unit in question, namely:
- The presence in the device of the power plant of the function of advancing the ignition process contributes to an increase in the sensitivity index of the throttle located on the gas pedal. This significantly expands the possibilities of driving a car;
- Water cooling of the gasoline-air mixture allows you to maintain an acceptable temperature in the engine, protecting it from the formation of gas-air jams;
- The advanced hydraulic drive control system makes it possible to significantly reduce the noise and vibration generated by a functioning motor.
Among other advantages of power units with the MPI marking, the following can be noted:
- Unpretentiousness to the quality of fuel. For domestic motorists, the possibility of using inexpensive AI-92 gasoline is especially attractive, which translates into significant savings in refueling;
- Reliability and strength of the structure. The manufacturer declared a minimum motor resource of 300 thousand km. However, trouble-free operation of the engine is impossible without periodic replacement of lubricants and filters;
- The extreme simplicity of the power unit is reflected in the cost and laboriousness of the repair.
You can't do without a fly in the ointment, which somewhat belittles the listed advantages of the MPI motor. In our case, a significant flaw in such engines is considered to be the power loss arising from the limited intake system. However, although the units under consideration lose dynamism due to the presence of eight valves in the timing mechanism, a measured calm ride with their help is ensured.
Conclusion
Having considered in detail all the advantages of MPI engines, and carefully weighing the disadvantages, it becomes unclear why the manufacturer refused their widespread use. If earlier almost all Volksvagen car models were equipped with such motors, today they are installed only on the second generation Skoda Octavia.
The design of power units is considered outdated and is gradually being phased out, being replaced by high-tech innovations.
The period of increased interest in gasoline engines MPI (the abbreviation stands for Multi Point Injection) came at the end of the last century and the beginning of this century. The demand for cars with such installations is due to the non-standard fuel injection scheme, which is built on a multi-point principle.
Each cylinder of such an installation has its own injector, as a result of which the fuel mixture is distributed as evenly as possible over all cylinders. The idea of an automobile engine with multipoint injection was implemented by Volkswagen, which significantly contributed to the emergence of an effective alternative to carburetor engines in the person of MPI. Let's try to take a closer look at what an MPI engine is and evaluate its competitive sides.
How modern is Multi Point Injection
A few years ago, it seemed that there were no future MPI engines, and it was even possible to believe that the production of such engines was completely suspended. This is not surprising, because the rapid development of automotive technology very soon makes one forget about what was considered a flagship or a benchmark of quality yesterday. Something similar is happening with MPI units, which many industry experts seem to be outdated and inconsistent with today's environmental and economic views.
If for the European market such conclusions are true, then for the Russian market it is only partly, because many domestic motorists have not yet discovered the real potential of these units. Fortunately, far-sighted manufacturers do not let the technology "die" and are still actively introducing it, for example, in the case of the second series Škoda Octavia, Volkswagen Polo, Volkswagen Golf 7, Škoda Yeti for Russian roads, etc. The most memorable representatives with MPI in recent years motors with a volume of 1.4 and 1.6 liters became.
MPI - the engine as it is
Along with the multi-point injection system, there is another significant detail - the complete absence of a turbocharger. In the presence of a typical gasoline pump that supplies fuel to the intake manifold under pressure of three atmospheres for subsequent mixture formation and the receipt of the finished composition into the cylinder through the intake valve. As you can see, the diagram is similar to what happens in engines with a carburetor, with the difference that each cylinder is equipped with a separate injector.
Multi Point Injection The engine is equipped with a water cooling circuit for the fuel mixture, which is somewhat unusual. Such a move is dictated by the fact that in the area of the cylinder head the temperature is quite high, while the pressure of the incoming fuel is relatively low, which is why there is a high probability of boiling and, as a result, the occurrence of a gas-air lock.
Pros and Benefits of MPI
Compatriots who have already been lucky enough to get to know MPI engines better, before switching to a car with a different engine, will probably think carefully whether they can get a set of those advantages thanks to which power plants with multipoint injection have won worldwide recognition:
- Simple device... It cannot be said that it is simpler than that of carburetor models, but in comparison with TSI engines equipped with injection pumps and turbochargers, the superiority is obvious, which is expressed in the cost of the car, not so significant operating costs and the ability to carry out many types of repairs on our own.
- Moderate requests for the quality of fuels and lubricants. This is especially important for Russia, since it is impossible to guarantee the availability of high quality gasoline and oils always and everywhere. MPI engines are quite unpretentious and feel good when using low-octane gasoline at least 92nd.
- Reliability. According to the developers, the minimum mileage without breakdowns for a car with MPI is at least 300 thousand km, but only on condition that the oil and filters are replaced on time.
- Low probability of overheating.
- Adjusting the ignition timing.
- The presence of a system of engine mounts. It is based on the use of rubber mounts. And although this is not directly related to the engine device, it still affects its "health" and the comfort of the owner, since the supports effectively dampen noise and vibrations that occur during movement. An interesting fact is that the adjustment of the supports for the operation of the motor is carried out automatically.
Cons and disadvantages of MPI
Among the disadvantages that force us to abandon the purchase and operation of machines with Multi Point Injection in favor of the newest models, there are only two points:
- Relatively high fuel consumption... With multipoint injection, such consequences cannot be avoided.
- Lack of torque and low power. The fact that mixing of fuel with air takes place in the intake ducts, and not in the cylinders, imposes certain restrictions. Cars with MPI cannot be classified as "high-spirited" and powerful; they are more designed for a leisurely move, and therefore drive lovers, most likely, will not like it. But such a car may well pretend to be a family car, because dynamics and power are not important for it.
If we compare all the possible pros and cons, then among the Russians there will certainly be many who believe with confidence that the power plants with MPI are still competitive. Obviously, German manufacturers also think so, having decided that the MPI engine would be the best option for the Russian version of the Škoda Yeti.
