ICE is classified according to the following criteria:
1 - by the nature of the working cycle - the supply of heat to the working fluid at a constant volume, constant pressure and with a mixed supply of bodies (i.e., first at a constant volume, then at a constant gas pressure);
2 - according to the method of carrying out the working cycle - four-stroke, in which the cycle is carried out in four consecutive strokes of the piston (in two crankshaft revolution), and two-stroke, in which the cycle is carried out in two consecutive piston strokes (in one revolution of the crankshaft);
3 - by the way of air supply - with and without pressurization. In 4-stroke ICEs without pressurization, the cylinder is filled with a fresh charge (air or hot mixture) by the suction stroke of the piston, in 2-stroke ICEs, it is a blow-off compressor with a mechanical drive from the engine. A supercharged internal combustion engine (they are called combined) has a turbocharger that supplies air to the engine at increased pressure;
4 - according to the method of fuel ignition - with compression ignition (diesel engines) and with spark ignition(carburetor and gas);
5 - by the type of fuel used - liquid fuel and gas;
6 - according to the method of mixture formation - with internal mixture formation, when the fuel-air mixture is formed inside the cylinder (diesel engines), and with external mixture formation, when this mixture is prepared before it is fed into the working cylinder. The main methods of internal mixing are volumetric, volumetric-film and film;
7 - by the type of combustion chamber (CC) - with unseparated single-cavity, with semi-divided (CC in the piston) and separated CC (pre-chamber, vortex chamber and air-chamber CC);
8 - according to the crankshaft speed n - low-speed with n < 240 мин -1 , среднеоборотные 240 < n < 750 min -1, increased speed 750< n < 1500 min -1 and high speed with n> 1500 min -1;
9 - by designation - main, intended for the drive of ship propellers, and auxiliary;
10 - according to the principle of action - simple action (the working cycle takes place in one cylinder cavity), double action (the working cycle takes place in two cylinder cavities - above and below the piston) and with oppositely moving pistons;
11 - according to the design of the crank mechanism (KShM) - trunk and crosshead;
12 - according to the arrangement of the cylinders - vertical, horizontal, single-row, double-row, V-shaped, star-shaped.
The main definitions are as follows:
- TDC and BDC, corresponding to the extreme positions of the piston in the cylinder;
- piston stroke, i.e. the distance between the extreme positions of the piston;
- the volume of the compression (or combustion) chamber corresponding to the volume of the cylinder cavity when the piston is at TDC;
- the working volume of the cylinder, which is described by the piston between the dead points.
For the marking of diesel engines produced in the CIS countries, legend, consisting of letters and numbers: Ч - four-stroke; D - two-stroke; DD - double-acting push-pull; Р - reversible; C - with a reversible clutch; H - supercharged. The absence of the letter K in the marking is a trunk engine.
Many have heard the alphanumeric combinations: 3S-FE, 2L-TE, SR20DE, EJ20, etc., but do not know what this means. But by name Japanese engines you can find out a lot of valuable information. We hope that this article will help you become, if not experts, then more enlightened people in this matter.
The names of Toyot engines are quite informative, second only to those of Nissan. So, the first character in the names of TOYOTA engines is the number intended to determine the serial number of the engine in the series. The second symbol tells us about the motor series (letter designation (it can also be two-letter)). As a rule, this part of the engine designation is written in the data sheet.
Consider an example with regards to the engine series, the S engine series, the 3S-FE and 4S-FE engines are structurally the same (not absolutely, but very similar), differ only in displacement and, if desired, they can even be swapped. Similarly, 1AZ - 2AZ (two-letter marking appeared on engine series that appeared after 1990), 2L - 3L (one-letter marking tells us that the series appeared before 1990), 1ZZ - 2ZZ, etc. Moreover, it is not necessary to bind the volume to the first figure, according to the principle, the larger the engine displacement, the larger the figure and vice versa, rather a smaller figure means an earlier year of development and nothing more. Do not confuse the year of the start of production of a particular engine model and the year of the beginning of the production of a new series.
Engines 3S-FSE, 5S-FE, 3C-TE, 2C-E (and many others) were developed after 1990, but since they belong to the old S and C series, they have one letter before the dash. But representatives of the series JZ, AZ, KZ, ZZ and others with the letter Z in the name, until 1990 there are none.
The name of the three-liter diesel 1KZ-TE (developed in 1993) is somewhat unusual, because its successor 1KD-FTV (also a three-liter diesel, but developed in 1996) has the letter D in its name. Presumably, since 1996, TOYOTA decided to use the letter D (Diesel) for the names of diesel engines, and the letter Z for gasoline engines. The letters after the dash indicate the design features of the engine, primarily the type of power supply and the type of timing.
The first letter (or its absence) after the dash denotes the features of the block head and the "degree of boost" of the engine. If it is the letter F, then this is a standard power engine with 4 valves per cylinder and two camshafts in the cylinder head, the so-called High Efficiency Twincam Engine. In such engines, only one of the camshafts is driven by a belt or chain, while the second is driven from the first through a gear (engines with a so-called "narrow" cylinder head).
4A-FE, 1G-FE, 3E-FE, 3S-FE, etc.
If the letter G is the first after the dash, then the engine is forced (there are also two camshafts in the cylinder head), on each of the camshafts there is a gear that has its own drive from the timing belt (chain). TOYOTA calls these engines High Performance Engine (engines with a "wide" cylinder head).
All engines with the letter G are gasoline and only with electronic fuel injection, often turbocharged or charger. Examples: 4A-GE (maximum speed 8000 rpm), 3S-GE (maximum speed 7000 rpm), 1ZZ-GE. F and G motors may be from the same series (for example, 3S-FE and 3S-GE). Based on this, we can say that they are developed on the same basis (cylinder diameter, piston stroke (but not the piston) and much more are the same), but the designs of the cylinder heads, timing and other engine elements differ.
The absence of the letters F or G after the dash means that the engine has only one intake and one exhaust valve per cylinder. 1G-E, 2C, 3A-L, 3L, 1HZ, 3VZ-E (and the camshaft will not necessarily be in the cylinder head) The second after the dash (or the first, if the engine has two valves per cylinder) is a letter carrying information about the features of the engine:
T - is available in all turbocharged engines (not to be confused with the charger): 1G-GTE, 3S-GTE, 4E-FTE, 2L-TE.
S - engine with direct fuel injection (development after 1996): 3S-FSE, 1JZ-FSE, 1AZ-FSE.
X - an engine that is a hybrid power plant type, usually working in tandem with one or more electric motors. 1NZ-FXE, 2AZ-FXE
P - an engine designed to work on liquefied gas (LPG (Liquefied Petrol Gas)): 15B-FPE, 1BZ-FPE, 3Y-PE
N - engine designed to run on compressed gas: 15B-FNE, 1BZ-FNE.
H - special fuel injection system, from some sources with variable intake manifold geometry (brand name: EFI-D): 5E-FHE, 4A-FHE
The third after the dash (or the first - the second, if an engine with two valves per cylinder and (or) does not belong to the category of engines having the letters T, S, N, X, P, H after the dash in the name) is a letter carrying information about the method mixture formation:
E - engine with multipoint electronic injection (EFI); for diesel engines, this means that they are equipped with an electronically controlled high pressure fuel pump (TNVD): 4A-FE (petrol), 1JZ-FSE (petrol), 3C-TE (diesel).
i - engine with single-point (mono-injection) electronic injection (Ci - Central injector): 4S-Fi, 1S-Fi
V - only available for diesel engines 1KD-FTV, 2KD-FTV, 1CD-FTV, apparently denotes a power supply system of the type Common rail(direct injection of diesel fuel).
If there are no letters E, i, V after the dash, then this is either a carburetor gasoline new engine, or a diesel engine with a conventional (mechanical) injection pump: 4A-F (carburetor engine, two-camshaft); 3C-T (diesel with mechanical injection pump) Fairly old gasoline TOYOTA engines(development before 1988) after the dash can have the letters U, L, C, B, Z: 1G-EU, 1S-U, 2E-L, 3A-LU
L - transverse arrangement of the engine (3A-LU) or generally transversal for MR2
U - reduced toxicity (for Japan) (+ catalyst)
C - reduced toxicity (for California) (+ catalyst)
B - Twin Carb - two carburettors (obsolete code)
Z - SuperCharger (mechanical supercharger): example: 1G-GZE, 4A-GZE
Examples of names of TOYOTA engines:
4A-FE - Gas engine with 4 valves per cylinder and "narrow" cylinder head, standard power range, with multi-point electronic fuel injection.
3C-T - diesel with 2 valves per cylinder, turbocharging and conventional (mechanically controlled) injection pump.
1JZ-GTE is a gasoline engine with 4 valves per cylinder, "wide" cylinder head, turbocharging and multi-point electronic fuel injection.
NISSAN engine markings are much more informative than engine names from other companies.
The first two letters in the name (gasoline engines had only one letter until 1983) designate the engine series. Similar to Toyota engines, engines of the same series are structurally similar, but may differ in the fuel injection system, the number of valves per cylinder, etc. For example TD23, TD25 and TD27 are identical in design, but differ in displacement. Moreover, if the letter V comes first, then this is necessarily a V-shaped engine. If the second is the letter D, then this is necessarily a diesel engine, if there is another letter, then it is a gasoline engine. Next comes the number, dividing by 10 you can get the working volume in liters: CA20DE (petrol, in-line, 2.0 liter, DOHC), A15S (petrol, in-line, 1.5 liter, two valves per cylinder), TD27 (diesel, in-line, 2.7 liters, two valves per cylinder), CD17 (diesel, in-line, 1.7 liters, two valves per cylinder), VG33E (petrol, V-shaped, 3.3 l., two valves per cylinder)
The first letter after the numbers indicates the design features of the cylinder head: D - an engine with 4 valves per cylinder (TWIN CAM (twin - two, cam (camshaft) - a camshaft) or DOHC - it's simple different names the same thing, there is no division as in TOYOTA into "narrow" and "wide" heads, all NISSAN engines camshafts are individually driven by a belt or timing chain). Example: ZD30DDTi, SR20DE, RB26DETT.
V - an engine with 4 valves per cylinder and variable valve timing (analogue of VTEC systems for HONDA or VVT-i for TOYOTA). Example: SR16VE, SR20VE.
If, after the numbers, the letter D or V is missing in the name of the NISSAN engine, this means that the engine has 2 valves per cylinder. Example: RB20E, CD20, VG33E.
The second letter after the numbers (or the first, if an engine with 2 valves per cylinder) indicates the method of forming the working mixture: E - multi-point (distributed) electronic fuel injection for gasoline engines (the system's brand name is EGI), in the names of NISSAN diesel engines this letter does not occur. Example: SR16VE, CA18E, RB25DE.
i - single-point (central) electronic fuel injection for gasoline engines (Ci - Central injector), for diesel engines this letter denotes an electronically controlled injection pump and is the last (not the second) in the engine name. Example: SR20Di (petrol), ZD30DDTi (diesel).
D - direct electronic fuel injection into cylinders - for gasoline engines (DI - Direct Input system); for diesel engines, this letter means that the engine is with unseparated combustion chambers. Both gasoline and diesel engines, with the letter D in the name, were developed after 1995. Example: VQ25DD (petrol); ZD30DDTi (diesel).
S - carburetor engine... Example: GA15DS, CA18S, E15ST.
If the name of the NISSAN engine does not contain letters after the numbers, (with the exception that the letter T may be present if the engine is equipped with a turbine), then this is a diesel engine with a conventional (mechanical) injection pump. Moreover, all such engines from NISSAN had two valves per cylinder and separated combustion chambers, that is, there are no letters D after the numbers in the names of these engines. Example: CD17, TD42T, RD28 The third letter after the numbers (or the first - the second) indicates the presence of turbocharging. If the letter T after the numbers is, it means that such a turbocharged engine (specifically with gas turbine charging, since the NISSAN concern, engines with a mechanical drive of the supercharger compressor from crankshaft did not release). If there are two T after the numbers, then this is a twin turbo engine (TWIN TURBO). Example: RD28T, RB25DETT, SR20DET, CA18ET
The fourth letter after the numbers can only be found in engines with two turbochargers (this is the letter T, for an example, see above) or in diesel engines with an electronically controlled injection pump. Example: RB25DETT, RB26DETT, YD25DDTi, ZD30DDTi.
Examples of NISSAN engine names:
A15S is a gasoline in-line engine with a working volume of 1.5 liters, with 2 valves per cylinder (ONS), a carburetor, without turbocharging.
CD17 is a diesel in-line engine with a working volume of 1.7 liters, with 2 valves per cylinder (ONS), a mechanical injection pump, without turbocharging.
VQ25DET - petrol V-shaped engine, displacement 2.5 l., With 4 valves per cylinder (DOHC = TWIN CAM), multi-point (distributed) electronic fuel injection (EGI) and turbocharging. ZD30DDTi - diesel in-line engine, displacement 3 , 0 l., With 4 valves per cylinder (DOHC) undivided combustion chambers, turbocharging and electronically controlled injection pump.
SR20Di is a gasoline in-line engine with a displacement of 2.0 liters, with 4 valves per cylinder (DOHC), central (single-point) electronic fuel injection, without turbocharging.
Names MITSUBISHI engines rather uninformative.
If the first character in the engine marking is a number, then it shows how many cylinders. Example: 4D56 (4 cylinders); 6G72 (6 cylinders); 3G83 (3 cylinders); 8A80 (8 cylinders).
The next letter gives information about the type of engine: A or G - gasoline engines. Example: 4G63, 8A80, 6G73.
1) D - diesel with a mechanically controlled high pressure fuel pump (HPF). Example: 4D56, 4D68.
2) M - diesel with electronically controlled injection pump. Example: 4M40; 4M41.
The last two digits indicate that the engine belongs to a particular engine series. Engines with the same name (and, accordingly, belonging to the same series) have a similar design, but may differ in the degree of forcing, displacement, and power supply. However, the 4G13 and 4G15 engines have a correspondence to the name of the working volume: the first has 1.3 liters, and the second has 1.5 liters, which is more an accident than a regularity. Based on the names of engines that are similar in design (that is, of the same series), it can be assumed that the last digit in the name is the volume code, and the first three characters are the series. For example: 1) 6A10, 6A11, 6A12, 6A13; 2) 6G71, 6G72, 6G73, 6G74.
Old MMC engines (developed before 1989) might not have the first number in the name showing the number of cylinders, but they had a letter at the end, and the names of the engines became similar to the names SUZUKI engines... Example: G13B (carbureted, 4-cylinder engine with 3 valves per cylinder)
The first letter in the engine name indicates that the engine belongs to a certain series. Like other Japanese engines, HONDA engines of the same series are structurally similar, but may differ in the degree of boost, displacement and other characteristics.
The next two numbers show the displacement of the engine, dividing the number by 10, we get the displacement in liters. Example: D17A (engine displacement 1.7 l.), B16A (engine displacement 1.6 l.), E07Z (engine displacement - 0.66 l.).
The last letter (there are letters A, B, C, Z) denotes a modification of the engine in a series, engines with a letter, and, similarly to the alphabet, the first modifications correspond to the first letters of the alphabet and then in descending order, that is, the first modification always has the letter A, the second B and further along analogies. Example: B20A, B20B; D13B, D13C; B18B, B18C.
Old HONDA engines have a two-letter designation, information about which can only be obtained from catalogs. For example: ZC (installed on the Integra model until 2001, it was in both carburetor and injection versions, as well as two-, single-camshaft, VTEC and simple)
The first one or two (in most cases) letters indicate that the engine belongs to the engine series. All engines of the series are structurally similar, but they can differ in displacement, the presence or absence of turbocharging (for example, the EJ20 can be with a turbine, with two turbines (twin turbo) or without them) and other elements.
The next two figures show the displacement of the engine, dividing the number consisting of these figures by 10 will give the displacement in liters. For example: EJ25TT (working volume 2.5 l., Twin turbo), EJ15 (working volume 1.5 l.), EF12 (working volume 1.2 l.), EN07 (working volume 0.66 l.), Z22 (working volume 2.2 l.).
Old SUBARU engines had in their name two numbers that have nothing to do with the working volume. EA71 (displacement 1.6 l.)
The engines of the old design had only two letters in their name, the new engine designs had additional letters after the dash, in addition, instead of two letters at the beginning, there can be a letter and a number or three letters.
The first letter in the name (of both new and old engines) indicates that the engine belongs to a certain series, the engines of which may differ in displacement.
The second letter indicates the modification in the series (usually an engine with a different displacement).
K8 (displacement 1.8 l.), FS (displacement 2.0 l.), R2 (2.2 l.), KL-ZE (2.5 l.)
Additional letters after the dash (for engines of the last years of development) are used to designate the design of the cylinder head and the method of filling the cylinders with the working mixture.
The first letter after the dash shows the design features of the cylinder head: Z or D - two camshafts(DOHC), 4 valves per cylinder. Example: JE-ZE, Z5-DE, KL-ZE
M - one camshaft, 4 valves per cylinder. Example: B3-MI, B5-ME.
R - for the Wankel rotary piston motor. Example: 13B-REW.
If the letters Z, D or M are missing after the dash, then this engine has 2 valves per cylinder (this applies to sufficiently fresh engines). Example: FE-E, JE-E, WL-T.
The second letter after the dash (or the first if the engine has 2 valves per cylinder) shows how the working mixture is created in the cylinders:
1) E - multi-point (distributed) electronic fuel injection. Example: FE-E, B5-ME.
2) I - single-point (central) electronic fuel injection. Example: B5-MI.
3) T - after the dash indicates the presence of turbocharging. Example: WL-T, RF-T.
The first letter indicates the series to which the engine belongs. Similar to others Japanese brands, all engines of the series are similar, but may have different displacement, injection system, and have slight design differences.
The next two numbers show the displacement of the engine, dividing this by ten, we get the displacement in liters.
K5B (0.55 L displacement), M13A (1.3 L displacement), J20A (2.0 L displacement), H25A (2.5 L displacement)
The first two letters indicate the series to which the engine belongs. All engines of the same series are structurally similar, but they can have different injection systems and head designs. Examples: EF-DET (turbocharged), EF-VE (naturally aspirated).
The letters following the dash speak of design features engine, but the purpose of some letters is not clear (for example, HE-EG and HD-EP engines).
T - the presence of turbocharging. Example: K3-VET.
D or Z - the presence of two camshafts. Example: EF-ZL, EJ-DE.
E - multi-point (distributed) electronic fuel injection. Example: HE-EG, HC-E
V - an engine with 4 valves per cylinder, two camshafts and variable valve timing (analogue of VTEC systems for HONDA or VVT-i for TOYOTA). Example: EJ-VE, K3-VET.
The first number in the engine marking indicates the number of cylinders in the engine.
The next two letters indicate that the engine belongs to the series. But at the same time, if of these two letters, the first is V, then the engine is V-shaped.
The last digit indicates the engine revision number in the series.
6VE1 - 6-cylinder V-shaped gasoline engine with a volume of 3.5 liters.
6VD1- 6-cylinder V-shaped gasoline engine with a volume of 3.2 liters.
4JX1 - 4-cylinder in-line diesel engine with a volume of 3.0 liters.
Survey:
1) The device of a 2-stroke engine.
2) The process of operation of a 2-stroke engine.
3) Theoretical diagram. Description.
4) Comparison of 2-stroke and 4-stroke engines.
New material:
1. Classification by purpose:
a) stationary and transport;
b) main and auxiliary.
2. Power classification.
According to the classification of TsNI CI, they are divided:
- less than 74 kW (100 hp) - low power;
- from 74 - 736 kW (100 - 1,000 hp) - average power;
- 736 - 7360 (1,000 - 10,000) - powerful.
- more than 7360 (10,000 hp) - super powerful.
3. Classification by duty cycle 2-stroke 4-stroke.
On a cycle with mixed combustion diesel engines, isochoric combustion.
Carburetor - automobile.
4. Classification by the type of fuel and mixture formation: gas; external mixture formation, internal, according to the ignition method, for engines with self-ignition of fuel from compression and gas-liquid engines with ignition fuel.
5. Classifications according to the method of filling the cylinder.
Filling the cylinder with high-pressure air is called supercharged: supercharged and naturally aspirated; mechanical pressurization M-400 and gas turbine M-401. combined supercharging is used on 2-stroke diesel engines.
6. Classification according to the combination of the main parts.
If the engine is started with compressed air, then a two-stroke must have at least 4 cylinders and a 4-stroke at least 6.
By arrangement of cylinders - in-line V-shaped angle of camber of cylinders 45º-90º; star-shaped.
7. By type crank actions trunk and crosshead; simple and double acting, double-acting only crosshead, rotary.
8. Classification by the nature of the movement: left rotation, right rotation. The direction of rotation is determined when viewed from the stern. Reversible with a change in rotation.
9. By frequency of rotation:
- up to 250 rpm - low-speed;
- 250-600 rpm - medium speed;
- 600 - 1,000 rpm - increased turnover;
- over 1,000 rpm. - multi-turn.
10. According to the average piston speed:
St< 6 м/с – тихоходные;
St = 6 -9 m / s - average speed;
St = 9 - 13 m / s - high-speed;
St> 13 m / s - increased speed.
St the average piston speed is determined by the formula, where:
S - piston stroke m / s;
n is the crankshaft speed.
Diesel marking.
According to GOST 4393-74, the diesel brand must include a combination of numbers and letters.
H- four-stroke;
D- two-stroke;
DD- two-stroke double action;
R- reversible;
WITH- with a reversible clutch (reverse);
NS- with gear transmission;
TO- crosshead;
N- supercharged;
G- gas.
This is followed by a fraction, the numerator means the diameter of the piston;
Denominator piston stroke in cm 8ChNSP 18/22 eight-cylinder four-stroke with air pressure and reverse gear, cylinder diameter 80 mm, piston stroke 220 mm.
6CH12 / 14, 6CHRN 36/45, 6DR 30/50
V GDR.
D (D)- diesel;
F (V)- four-stroke;
H (H)- middle stroke after three letters the piston stroke in (cm) is indicated.
4 NFD 24.
8 NFD 48.2 AU- eight-cylinder, medium-stroke, four-stroke diesel engine with a piston stroke of 480 mm, the second modernization, supercharged, reversible.
V Czech Republic it is customary to apply the brand of the engine with the number of cylinders and the piston diameter in cm (in mm), the letters mean L (L) - ship; C (S) - stationary; Рр (Rr) - with mechanical and manual reverse. PN (PN) - supercharged.
But this principle is not strictly adhered to. 6C 275 L - not stationary, but marine 6L 275 Rr / II PN - six-cylinder engine with mechanical and manual reverse, with 275 mm cylinder pressurization, the second modernization.
The marking of engines made in the Czech Republic is undergoing constant changes. It contains the letters A, B or C meaning the type of engine and numbers that characterize the degree of boost.
1 - low; 2-3 - medium; 4 - high.
Example: 6 27.5 А 2 L - six-cylinder engine with a cylinder diameter of 275 mm, type A, marine, supercharged stage 2.
Lesson 4. Topic: Mixing and combustion of fuel in diesel cylinders.
Combustion process. The concept of hard and soft work of the internal combustion engine.
1. General concept of fuel.
Fuel refers to combustible substances that are burned in order to obtain thermal energy. Fuel is liquid and gaseous. The main chemical elements that make up the fuel are carbon and hydrogen. The carbon content of oil and petroleum products is 83-87% hydrogen 11-14% of the total fuel mass.
The main property that determines the value of fuel is the heat of combustion. It is called the amount of heat released during the complete combustion of 1 kg of fuel.
Combustion of fuel in a diesel engine.
Autoignition delay.
The fuel injected into the cylinder does not ignite immediately. First, its particles evaporate, mix with air and the mixture heats up to autoignition temperature. This process is strong and multifaceted. Consequently, after injection of fuel particles into the cylinder, an ignition delay occurs due to physical and chemical preparatory processes. The time elapsed from the moment the particles enter the cylinder until the start of combustion is called the autoignition delay period.
The autoignition delay period is 0.001-0.005 s. If we assume that the engine operates at a speed of 750 rpm, then its crank rotates by 1º in about 0.0002 s, which means that during the autoignition delay period the crank will rotate by an angle of 5 to 25º.
This circumstance forces fuel injection to be performed ahead of time, i.e. before the crank piston comes to TDC.
The angle at which the crank does not reach TDC is called - Fuel feed advance angle - this is the most important parameter of the engine regulation in marine diesel engines about 15-33º.
Combustion progress.
d - the point of the beginning of the fuel supply;
d 0 - fuel feed advance angle;
d i is the angle of rotation of the crankshaft during the ignition delay period or (ignition delay period).
c - the point of the beginning of combustion during the ignition delay period (angle d i) a certain amount of fuel has entered the cylinder, which is usually 15-50% of the cycle supply, i.e. on the dose injected per cycle.
The fuel ignites, hence the temperature and pressure rise sharply section (cz). The fuel entering the cylinder at the end of the delays burns quietly, leaving, so to speak, into a fiery environment.
Its combustion ends a little later than the injection.
At this time, the piston moves down, the volume under it increases and the pressure does not change significantly in the area (z 1, z).
(z - z 0) - the section shows the expansion process (the fuel in this section burns out).
Section (cz ') is characterized by an intense increase in pressure from Pc to Pz. If the slew rate is more than 400-600 kPa / deg. P.K.V. (4-6 kgf / cm 2), then the load on the piston will be shock, there will be a knock in the cylinder, this engine operation is called tough... Hard work is extremely harmful and affects bearing wear, deformation and breakage of piston rings.
The severity of engine operation depends on the rate of pressure rise after autoignition, and this rate depends on the amount of fuel that entered the cylinder during the autoignition delay period. In short, the hardness of the diesel engine depends on the magnitude of the autoignition delay period: the longer it is, the harder the diesel engine will be.
This means that to ensure the smooth operation of the diesel engine, one should strive to reduce the autoignition delay period (adjustment before the angle - advance of the fuel supply).
An increase in the temperature of the compressed air in the cylinder contributes to a decrease in the autoignition delay period. A cold diesel engine works with “knocks” in the cylinder; after heating, the “knocks” disappear.
An increase in the compression pressure contributes to a decrease in the autoignition delay period, which is explained by a decrease in the autoignition temperature with increasing pressure. Smooth operation of the engine is possible with a good density of the piston in the cylinder, with a given compression ratio and keeping the engine warm - hot.
Hard operation of the diesel engine is possible when the nozzle needle hangs (nozzle) - poor spray quality.
The hardness of the diesel engine depends on the self-igniting fuel - this quality is characterized by the cetine number. It is determined by comparing the autoignition of the fuel under study and two reference hydrocarbons: cetane C 16 H 34 and alphamethylnaphthalene C 10 H 7 CH 3, the first has a minimum autoignition delay period, the second is significant. (The comparison is made on a special single-cylinder engine with a variable write-off rate). First, the compression ratio is determined at which the fuel under study ignites spontaneously when the piston is positioned strictly at TDC.
Then an equivalent mixture of cetane and alphamethylnaphthalene is selected, i.e. one that, at the same fuel feed advance angle and at the same compression ratio, spontaneously ignites at the position in V.M.T.
The cetane number of a fuel is the percentage of cetane in its mixture with alphamethylnaphthalene, which is equivalent to the fuel in terms of flammability. If, for example, the equivalent mixture contains 45% cetane, and 55% alphamethylnaphthalene, then the cetane number of the fuel will be 45. Sufficiently soft operation of high-speed diesel engines with a cetane number of 45. Low-speed diesel engines can operate with a cetane number below 40.
An increase in the cetane number over 55 causes a decrease in the completeness of fuel combustion. Excessive reduction of the autoignition delay period leads to a sluggish combustion process, which reduces efficiency.
Lesson number 5. 2/10. (pp. 33-37) Mixture formation in diesel engines.
Survey:
1) Delay of self-ignition, the essence of the process.
2) The course of the combustion process.
3) The concept of hard and soft work of a diesel engine.
4) Cetane number, physical meaning.
New material:
Mixing is the process of preparing a combustible mixture in order to prepare the fuel for combustion.
The aggregate of particles of atomized fuel, formed at the exit from the nozzle of the injector, is called a fuel flame. It is characterized by an angle and a length L. The vertical angle between the axes of the torches is called the spray angle.
Length, torch angle and split angle are consistent with the combustion chamber. The torch should cover the entire thickness of the air in the chamber, but fuel particles should not fall on the cooled surfaces to avoid coking.
The more torches the better, but usually according to the number of nozzle holes; 6-8, Ø 0.20-0.5 mm. The nozzle orifice represents a channel with a length (which is 4-7 times its diameter). Due to the friction of the outer layer of the fuel, the jet disintegrates in the channel. When leaving it, the threads of fuel meet the resistance of compressed air and break up into particles and form a fuel torch.
For good mixture formation, the fuel flow rate should be 250-350 m / s. To achieve this speed, the injection pressure must be 40-80 MPa (400-800
kgf / cm2) and higher. Fuel injection duration is 15-40º angle P.K.V.,
and the fast ones have even more
To obtain a mixture formation process, it is necessary that the injection speed should increase and have a maximum value at the moment the injection is stopped. Therefore, the profile of the cam washer of the fuel pump is made such that the injection pressure rises after it starts. The initial injection pressure for marine diesel engines is 18-38 MPa ( 180-380 kgf / cm 2).
2. The shape of the combustion chambers.
Hemispherical, Gesselmann, intermediate, combustion chamber in the piston (TsNIDI), (single-chamber mixture formation).
3. Vortex chamber education.
When organizing single-chamber mixture formation in engines of small sizes, with small cylinder diameters, there is little room for the development of a fuel flame, with low power, a very small volume of fuel is injected into the cylinder, therefore, to achieve a high injection speed, it is necessary high pressure and small cross-sections of nozzle openings (for YaAZ 204 engines, Ø 0.15 mm, the injection pressure reaches 140 MPa or 1400 kgf / cm 2, such an engine is very sensitive to the quality of the fuel and the quality of maintenance of the fuel equipment.
Marine diesels should be simpler and undemanding to the quality of service.
Therefore, multi-chamber mixture formation and its variety, vortex chamber, have found wide application.
Reference. Vortex-chamber mixture formation allows to obtain high-quality mixture formation with small injection engines (12-24 MPa), 120-240 kgf / cm 2.
Advantages of vortex chamber mixing; you can get more power than with single-chamber mixture formation, the combustion process is better (more air), less sensitive to the quality of the fuel.
Disadvantages; less economical, because the flow of air and working gas into the vortex chamber spends part of the internal energy of the gas. The design of the cylinder head becomes more complex.
Due to the division of the volume of the combustion chamber into two parts, the surface per unit volume of air increases.
The increased heat removal through the walls in this regard reduces the temperature of the compressed air, which makes it difficult to start a cold diesel engine.
Trends in improving mixture formation (read in a lesson with cadets - p. 37).
There are many situations when you just need to find out the engine model. For example, when buying a car or just spare parts. And then the question arises: how and where to get this information? Next, it will tell you how to determine the engine model in the following ways: find the number on the engine using the engine compartment plate and by the wine code.
On the engine itself
Let's say right away that looking for a number on an engine is not the easiest way. Although, it would seem: he opened the hood, found the engine, found the number and entered it into a search engine. But not everything is so simple.
Where is the engine number
At first, the number can be stamped on a variety of places on the engine. It all depends on the make and model of the car. Although more often it can be found on the upper part, the one closer to the windshield. well and Secondly, the room itself may be in such a state that it is impossible to figure it out without a rust remover and a brush, or even completely destroyed by corrosion.
Interesting fact! In some cars made in the United States, the number on the engine is simply missing. This only applies to older models.
What information is written there
As soon as it was possible to find the engine number, you can proceed to parsing the information that it stands for. Although, depending on the brand, there are some differences, but basically the marking is 14 characters. They are conventionally divided into two blocks: descriptive (6) and indicative (8).
Pay attention to the first one. The first three digits in the descriptive block indicate the index of the base model. This is followed by the modification index (if there is none, set zero), climatic version and either the Latin "A" (meaning diaphragm clutch) or "P" (recirculation valve). In the index part, first the year of issue is indicated (by a number or letter of the Latin alphabet), then the month (by the next two numbers). The remaining 5 characters indicate a sequential number.
Remember! Numbers from 1 to 9 indicate 2001-2009 years of release, Latin "A" - 2010, B - 2011, C - 2012, etc.
Nameplate under the hood
How to find out the model of the engine by fault, we will tell further, and now we will pay attention to the plate on which this is also indicated. It is located under the hood of most cars and is called the engine compartment. With the help of numbers and letters, all the necessary information is provided here (car model, engine type, cylinder volume, frame number or an identification number, color code and trim code, drive axle, manufacturer's plant and type of transmission). Depending on the car brand, it can be fed in a different sequence. For decryption, you will have to use special literature or appropriate resources.
Did you know?First engine project internal combustion was introduced back in the 17th century by the Dutch inventor Christian Huygens.
Find out the engine by the wine code
The third method will explain how to find out the engine model by the wine code. Vehicle Identification Number, abbreviated as VIN. They began to assign such a number to cars in America and Canada. This is a unique identification number consisting of 17 numbers and letters. With it, you can find out almost everything about a particular car. And, of course, there is information about the engine model. It is enough to look at the vehicle registration certificate to find out the data (from the year of modification to the code) of the engine by vin.
Although you can do without it by looking at the code on the machine itself. Since there are no strict rules for the location of the wine code, it can be seen near passenger seat... But more often it is located between the windshield and the engine.
The wine code is divided into 3 parts of three, six and eight characters. Only numbers and Latin letters are used (except for I, O, Q due to the similarity with numbers). The first one talks about the manufacturer, the second one describes vehicle, the third is distinctive.
The first or third characters speak about the country, manufacturer and type of vehicle, that is, this is the manufacturer's world code. In order to find out the modification of the engine by the wine code, you need to pay attention to the second part. It will indicate the body type, engine and model. Next, there will be a variety of information, which can indicate both the type of body, chassis, cab, and the series of the car, type brake system etc. The ninth digit of the code is a verification one.
The third part also indicates useful information... For example, the first character of this part (the 10th character of the code) indicates the model year, the second indicates the assembly plant.
Important! Be sure to check the vin code on the car and in technical passport at the time of buying. If inconsistencies are found, then it is worth not only abandoning the deal, but also informing the law enforcement agencies.
If you need to find out the model of the engine, then you can easily use the three described methods (by the number on the engine itself, on the engine compartment plate or by the wine code). Whichever method you choose, you should use special literature or online services to decipher the characters yourself.
Very often, when repairing, as well as replacing a particular unit, or an automobile unit, it is often necessary to determine the model power unit... Using this data, you can select necessary spare parts or order a new engine for a car.
And so, I bring to your attention the instructions for determining the type and brand of the engine, as well as some of its properties.
1. Identification of the power package should start with a number, which is usually on the left side. For this, there is a special platform on the cylinder block. Typically, the labeling consists of two parts - descriptive and indicative. The descriptive part consists of six characters, and the index part contains eight characters. The first character is a Latin letter or number, it denotes the year of manufacture of the engine. For example, nine means 2009, and the letter A, in turn, means 2010, and so on, B means 2011 ...
2. The first three digits of the descriptive part are the base model index, the fourth is the modification index. If there is no modification index, it is customary to set it to zero.
3. The fifth figure is climatic version. The last digit is usually either the diaphragm clutch, which can be (A), or the recirculation valve (P). On domestic cars brand VAZ, for example, the number, as well as the model of the engine, the manufacturer knocks out on the back of the end of the cylinder block.
4. On cars of the GAZ brand (Gorky Automobile Plant), a slightly different placement of this engine number is characteristic. On GAZons, the marking should be found in the lower left part of the cylinder block.
Toyota Company with the first digit indicates the serial number in the series, and only the second - the series of the engine. Suppose an engine marked 3S-FE and 4S-FE, despite the structural similarity, have differences only in different working volumes.
5. If the marking contains the letter G, this means that the unit is gasoline and has electronic injection and is most likely equipped with a charger or turbine. Letter F means - cylinders with four valves, two camshafts and a separate actuator. The letter T - indicates the presence of turbines, and the Z - supercharger. Here is an example of such a marking 4A-GZE. The presence of the letter E - can mean that the car is equipped with electronic injection, and S - that the engine is equipped with a direct injection system, and finally X - indicates the relationship of the engine to hybrids.
6. Engine Nissan brands have more informative labeling. The first and second letters are a series, the next two are the volume of the motor. In order to find out what volume of the engine in cubic centimeters, you need to multiply this figure by 100. 4-valve engines will be marked on the cylinder with the letter D. V - variable valve timing, E - electronic multipoint injection. The letter S - in carburetor units, one letter T - one turbine, respectively, two - TT.
