Inlet (1st measure). The piston goes down to bottom dead center. The intake valve opens and the air-fuel mixture rushes into the cylinder.
Compression (2nd measure). The piston moves from bottom dead center to top dead center. The inlet valve closes. The piston compresses the mixture.
Combustion (3rd measure). Shortly before reaching top dead center, the spark plug sparks. The mixture burns and presses on the piston, which moves to bottom dead center. The connecting rod drives the crankshaft.
Release (4th measure). The piston moves up again. The exhaust valve opens, the burnt gases are pushed out into the exhaust system.
The working volume of the cylinder. The volume that the pistons pass during movement from bottom dead center to top. When the piston reaches its highest point, there is still a combustion chamber in which the air-fuel mixture is located. The working volume and the combustion chamber together form the volume of the cylinder.
Compression ratio. The ratio between the volume of the cylinder and the volume of the combustion chamber. This value indicates to what part of the volume of the cylinder the air-fuel mixture is compressed. Gasoline engines typically have a compression ratio of about 10:1 (in diesel engines about 20:1).
The working volume of cylinder 2 extends from the top 1 to the bottom dead center 3. Between the top dead center, at which the piston bottom is located in the right cylinder in this figure, and the arch of the cylinder head 5 is the combustion chamber 4.
Overspeed and engine life
Exceeding the rated speed will shorten the life of the motor. If the engine rotates too fast, then a characteristic sound occurs, the cause of this is vibration of the crankshaft or vibration of the valve train parts. If the oscillations become too strong, then some pusher may break as a result. The corresponding valve drops out of operation, and the cylinder stops producing power. This manifests itself in the form of a decrease in engine power. In the worst case, the valve springs can break, causing the valve to fall on the piston, which moves up and down. This usually means severe engine damage.
Visitor comments