The order of operation of the cylinders in different engines is different, even with the same number of cylinders, the order of operation may be different. Consider the order in which serial internal combustion engines of various cylinder arrangements work and their design features. For the convenience of describing the operation of the cylinders, the countdown will be made from the first cylinder, the first cylinder is the one in front of the engine, the last, respectively, near the gearbox.
3 cylinder
In such engines, there are only 3 cylinders and the operation procedure is the simplest: 1-2-3
. Easy to remember and fast.
The layout of the cranks on the crankshaft is made in the form of an asterisk, they are located at an angle of 120 ° to each other. It is possible to apply the 1-3-2 scheme, but manufacturers did not begin to do this. So the only sequence in a three-cylinder engine is the 1-2-3 sequence. To balance the moments from the forces of inertia on such engines, a counterweight is used.
4 cylinder
There are both in-line and boxer four-cylinder engines, their crankshafts are made according to the same scheme, and the order of operation of the cylinders is different. This is due to the fact that the angle between the pairs of crankpins is 180 degrees, that is, the 1st and 4th journals are on opposite sides of the 2nd and 3rd journals.
1 and 4 necks on one side, 3 and 4 on the opposite side. In in-line engines, the order of operation of the cylinders is applied 1-3-4-2 - this is the most common scheme of work, this is how almost all cars work, from Zhiguli to Mercedes, gasoline and diesel. Cylinders with crankshaft journals located on opposite sides work in series in it. In this scheme, you can apply the sequence 1-2-4-3, that is, swap the cylinders, the necks of which are located on the same side. Used in 402 engines. But such a scheme is extremely rare, they will have a different sequence in the operation of the camshaft.
The boxer 4-cylinder engine has a different sequence: 1-4-2-3 or 1-3-2-4. The fact is that the pistons reach TDC at the same time, both on the one hand and on the other. Such engines are most often found on Subaru (they have almost all the opposites, except for some small cars for the domestic market).
5 cylinder
Five-cylinder engines were often used on Mercedes or AUDI, the complexity of such a crankshaft lies in the fact that all connecting rod journals do not have a plane of symmetry, and are rotated relative to each other by 72 ° (360/5 \u003d 72).
The order of operation of the cylinders of a 5-cylinder engine: 1-2-4-5-3
,
6 cylinder
According to the arrangement of cylinders, 6-cylinder engines are in-line, V-shaped and boxer. A 6-cylinder engine has many different cylinder sequence schemes, they depend on the type of block and the crankshaft used in it.
inline
Traditionally used by a company such as BMW and some other companies. The cranks are located at an angle of 120° to each other.
The order of work can be of three types:
1-5-3-6-2-4
1-4-2-6-3-5
1-3-5-6-4-2
V-shaped
The angle between the cylinders in such engines is 75 or 90 degrees, and the angle between the cranks is 30 and 60 degrees.
The sequence of operation of the cylinders of a 6-cylinder V-shaped engine can be as follows:
1-2-3-4-5-6
1-6-5-2-3-4
Opposite
6-cylinder boxers are found on Subaru cars, this is the traditional engine layout for the Japanese. The angle between the crankshaft cranks is 60 degrees.
Engine sequence: 1-4-5-2-3-6.
8 cylinder
In 8-cylinder engines, the cranks are installed at an angle of 90 degrees to each other, since there are 4 strokes in the engine, then 2 cylinders work simultaneously for each stroke, which affects the elasticity of the engine. 12-cylinder runs even softer.
In such engines, as a rule, the most popular uses the same sequence of cylinders: 1-5-6-3-4-2-7-8 .
But Ferrari used a different scheme - 1-5-3-7-4-8-2-6
In this segment, each manufacturer used only the sequence known to him.
10 cylinder
A 10-cylinder engine is not very popular, manufacturers rarely used such a number of cylinders. There are several options for ignition sequences.
1-10-9-4-3-6-5-8-7-2 - used on Dodge Viper V10
1-6-5-10-2-7-3-8-4-9 — BMW charged versions
12 cylinder
The most charged cars were equipped with 12-cylinder engines, for example, Ferrari, Lamborghini, or the more common Volkswagen W12 engines.
If you think about it, then why do we, ordinary motorists, need to know the order in which the cylinders of a car work? Well, they work properly and, thank God. Yes, of course, it is difficult and completely pointless to deny this, but only until the moment when you want to set up the ignition or adjust the valve clearances with your own hands. And then this knowledge about the operation of automobile cylinders will be absolutely not superfluous. Do you want to connect high voltage wires to spark plugs or high pressure pipelines on a diesel engine. What if you decide to sort out the cylinder head? Agree that it would be a little silly to go to the service station with the need for the correct installation of high-voltage wires. And how do you do it when the engine is troit?
The order of operation of the cylinders, what does this mean?
The sequence with which the cycles of the same name alternate in different cylinders is called the order of operation of the cylinders. On what factors does this parameter depend? What determines the order of the cylinders? There are several of them, and we will list them now:
- arrangement of cylinders in the engine: in-line or V-shaped;
Number of cylinders;
Camshaft design;
Design features and type of crankshaft.
Cylinder phases
The working cycle of an automobile engine is divided into gas distribution phases. Their sequence must be evenly distributed on the crankshaft according to the strength of their impact. Only in this case the engine will work evenly. A necessary and strict condition is to find the cylinders operating sequentially relative to each other. They just shouldn't be next to each other. It is for this purpose that engine manufacturers develop schemes that indicate the order of operation of the engine cylinders. But all schemes are united by a single factor: the order of operation of all cylinders begins with the main cylinder at number one.
Different engines - different workflow
Engines of the same type with different modifications may have differences in cylinder operation. Let's take the ZMZ engine as an example. The order of operation of the 402 engine is 1-2-4-3, although the cylinders of the 406 work in a completely different order - 1-3-4-2.
If we dive deeper into the theory of the operation of an internal combustion engine, but not much, so as not to get confused, then we can see the following: A four-stroke engine goes through its full cycle in two revolutions of the crankshaft. When viewed in degrees, this equals 720 degrees. A two-stroke engine has 3600 degrees. In order for the crankshaft to be constantly under piston force, its knees are displaced at a certain angle. The degree of this angle directly depends on the engine cycle and the number of cylinders. An inline four-cylinder engine cycles every 1800 degrees. The order of operation of such a motor on VAZ cars is as follows: 1-3-4-2, on GAZ cars 1-2-4-3. The six-cylinder in-line engine runs in this order: 1-5-3-6-2-4, the cycle alternation is 1200 degrees. The eight-cylinder V-engine operates in this mode: 1-5-4-8-6-3-7-2, ignition occurs at an interval of 900 degrees. The order of operation of the twelve-cylinder W-shaped engine is interesting: 1-3-5-2-4-6 - the operation of the left cylinder heads, and the right ones: 7-9-11-8-10-12
In order for you not to get confused with all these digital orders, let's look at one example. Let's take an eight-cylinder engine of a ZIL truck with the following order of operation of its cylinders: 1-5-4-2-6-3-7-8. The location of the cranks is at an angle of 900 degrees. Let's take the first cylinder, during its working cycle 90 degrees of crankshaft rotation occur, then the cycle goes to the fifth cylinder and so on sequentially in the following order 4-2-6-3-7-8. In this case, one revolution of the crankshaft equates to four work cycles. The conclusion from all this is obvious - an eight-cylinder engine runs much more evenly and smoothly than a six-cylinder one.
Yes, we agree that such a deep knowledge of the operation of the engine cylinders of your car will most likely not be useful. But at least you should have a general idea about it. And if you are overtaken by the need to repair the cylinder head, then this knowledge will certainly not be superfluous. Friends, we wish you success in learning these wisdoms!
In most cases, an ordinary car owner does not need to understand the operation of the engine cylinders at all. However, this information is not needed until the motorist has a desire to independently set the ignition or adjust the valves.
Repair, diagnostics, service - The order of operation of engine cylinders on different cars - - Ordering spare parts
Information on the order of operation of the car engine cylinders will certainly be needed if you need to connect high-voltage wires or pipelines in a diesel unit. Become published in the public Machines. In such cases, it is sometimes simply impossible to get to a service station, and knowledge of how the engine works is not always enough.
The order of operation of the engine cylinders - theory:
The order of operation of the cylinders is called the sequence with which the cycles alternate in different cylinders of the power unit. This sequence depends on the following factors:
Number of cylinders; type of cylinder arrangement:
V-shaped or in-line;
Structural features of the crankshaft and camshaft.
Engine duty cycle features:
What happens inside the cylinder is called the engine's duty cycle, which consists of certain valve timing.
The gas distribution phase is the moment at which the opening begins and the closing of the valves ends. The valve timing is measured in degrees of rotation of the crankshaft in relation to the top and bottom dead centers (TDC and BDC).
During the operating cycle, a mixture of fuel and air ignites in the cylinder. The interval between ignitions in the cylinder has a direct effect on the uniformity of the engine. The engine runs as evenly as possible with the shortest ignition gap.
This cycle directly depends on the number of cylinders. The larger the number of cylinders, the shorter the ignition interval will be.
The order of operation of the engine cylinders of different cars:
It must be understood that one working cycle of a four-stroke engine is equal in duration to two revolutions of the crankshaft. If you use a degree measurement, then it is 720 °. For a two-stroke engine, it is 360°.
The shaft knees are located at a special angle, as a result of which the shaft is constantly under the force of the pistons. This angle is determined by the cycle time of the power unit and the number of cylinders.
The firing order of a 4 cylinder engine with a 180 degree firing interval can be 1-2-4-3 or 1-3-4-2;
The order of operation of a 6-cylinder engine with an in-line arrangement of cylinders and a 120-degree interval between ignitions is as follows: 1-5-3-6-2-4;
The order of operation of an 8 cylinder engine (V-shaped) is 1-5-4-8-6-3-7-2 (90-degree interval between ignitions).
In each engine scheme, regardless of its manufacturer, the cylinder firing order begins with the master cylinder, marked with number 1.
This engine includes a four-stroke diesel YaMZ-236. The camber angle between its cylinders is 900. The crankshaft knees are located in three planes at an angle of 1200 to one another. A feature of this engine is a crankshaft having three cranks, each of which is connected to two connecting rods: to the first crank - the connecting rods of the first and fourth cylinders; to the second of the second and fifth cylinders and to the third - of the third and sixth cylinders.
In this engine, which has an operating order of 1 - 4 - 2 - 5 - 3 - 6, the same cycles in the cylinders occur unevenly after 90 and 1500 (Table 4). If a working stroke is carried out in the first cylinder, then in the fourth it starts after 900, in the second - after 1500, in the fifth - after 900, in the third - after 1500 and in the sixth - after 900. Therefore, the YaMZ-236 engine has an increased stroke unevenness and in it has to install a flywheel on the crankshaft with a relatively large moment of inertia (60070% greater than for a single-row engine).
Eight-cylinder V-engine. The cylinders in such an engine (for example, the engines of GAZ-53A, GAZ-53-12, ZIL and KamAZ-5320 cars) are located at an angle of 900 to one another (Fig. 24.6). The cycles of the same name in the cylinders begin through the angle of rotation of the crankshaft.
Rice. 24 - Schemes of the crank mechanism of four-stroke V-shaped engines:
a - six-cylinder; b - eight-cylinder; 1-8 - cylinders.
Table 4. The alternation of cycles in a four-stroke V-shaped six-cylinder engine with the order of operation 1 - 4 - 2 - 5 - 3 - 6.
The inlet is equal to 720: 8 = 900. Therefore, the crankshaft cranks are located crosswise at an angle of 900. The connecting rods of the first and fifth cylinders are attached to the first crank, the connecting rods of the second and sixth cylinders are attached to the second, the third and seventh cylinders are connected to the third, and the fourth and fourth cylinders are connected to the fourth. eighth cylinder. In an eight-cylinder four-stroke engine, eight power strokes are completed in two revolutions of the crankshaft. The overlapping of working strokes in various cylinders occurs during the rotation of the crankshaft at an angle of 90 ° C, which contributes to its uniform rotation. The order of operation of the eight-cylinder engine 1 - 5 - 4 - 2 - 6 - 3 - 7 - 8 (Table 5).
Table 5
Knowing the order of operation of the engine cylinders, you can correctly distribute the wires to the spark plugs, connect the fuel line to the injectors and adjust the valves.
Operation of a multi-cylinder engine
depends on the type of engine (arrangement of cylinders) and on the number of cylinders in it.
For a multi-cylinder engine to run smoothly, the expansion strokes must follow at equal crank angles (i.e., at regular intervals). To determine this angle, the cycle time, expressed in degrees of rotation of the crankshaft, is divided by the number of cylinders. For example, in a four-cylinder four-stroke engine, the expansion stroke (power stroke) occurs through 180 ° (720: 4) with respect to the previous one, that is, through half a revolution of the crankshaft. The other cycles of this engine also alternate through 180°. Therefore, the connecting rod journals of the crankshaft for four cylinder engines are located at an angle of 180 ° to one another, that is, they lie in the same plane. The connecting rod journals of the first and fourth cylinders are directed in one direction, and the connecting rod journals of the second and third cylinders are directed in the opposite direction. This shape of the crankshaft provides a uniform alternation of strokes and good engine balance, since all pistons simultaneously come to the extreme position (two pistons down and two up).
The sequence of alternation of the same cycles in the cylinders is called the order of operation of the engine. The order of operation of four-cylinder domestic tractor engines 1-3-4-2. This means that after the stroke in the first cylinder, the next stroke occurs in the third, then in the fourth and finally in the second cylinder. A certain sequence is observed in other multi-cylinder engines.
When choosing the order of engine operation, designers strive to distribute the load on the crankshaft more evenly.
The cycles of the same name in a four-stroke six-cylinder engine are performed through a rotation of the crankshaft by 120 °. Therefore, the connecting rod journals are arranged in pairs in three planes at an angle of 120°. In a four-stroke eight-cylinder engine, the same cycles occur through 90 ° of crankshaft rotation and its connecting rod journals are located crosswise at an angle of 90 ° to one another.
In an eight-cylinder, four-stroke engine, two revolutions of the crankshaft make eight strokes, which contributes to its uniform rotation.
The order of operation of eight-cylinder four-stroke engines is 1-5-4-2-6-3-7-8, and six-cylinder engines are 1-4-2-5-3-6.
Knowing the order of operation of the engine cylinders, you can correctly distribute the wires to the spark plugs, connect the fuel lines to the injectors and adjust the valves.
22 Forces and moments acting in the kms of a single-cylinder engine
During the combustion-expansion cycle, the force P1 applied to the piston pin is composed of two forces:
force P of gas pressure on the piston
inertial forces Pi (inertial force is variable in magnitude and direction)
The total force P1 can be decomposed into two forces: the force S, directed along the axis of the connecting rod, and the force N, which presses the piston against the cylinder walls.
We transfer the force S to the center of the connecting rod journal, and apply two equal forces S and parallel forces S1 and S2 to the center of the crankshaft. Then the combined action of the forces S1 and S will create (on the shoulder R) a torque that rotates the crankshaft, and the force S2 will load the main bearings and through them will be transmitted to the engine crankcase.
Let us decompose the force S2 into two perpendicularly directed forces N1 and P2. The force N1 is numerically equal to the force N, but is directed in the opposite direction; the joint action of the forces N and N1 forms a moment Nl, which tends to overturn engine in the direction opposite to the rotation of the crankshaft. The force P2, numerically equal to the force P1, acts downward, and the force P acts upward on the cylinder head, i.e. in the opposite direction. The difference between the forces P and P1 is the inertia force of the progressively moving masses Ri. This force reaches its greatest value at the moment of changing the direction of piston movement.
The rotating masses of the connecting rod journal, the crank cheeks and the lower part of the connecting rod create a centrifugal force Pc directed along the radius of the crank away from the center of rotation.
Thus, in the crank mechanism of a single-cylinder engine, in addition to the torque that occurs on the crankshaft, a number of unbalanced moments and forces act, such as:
reactive, or overturning, moment Nl, perceived by the engine mounts through the crankcase
inertia force of translationally moving masses Ri, directed along the axis of the cylinder
centrifugal force of rotating masses Rc, directed along the shaft crank
The lateral force N reaches its greatest value when the gases expand, when the piston is pressed against the left wall of the cylinder, which explains its usually greater wear.
