V-55 battle tank engine

The intake stroke is performed when the piston moves away from the upper center. to n.m.t. Since the volume of the cylinder above the piston at this time increases, the pressure in it becomes less than atmospheric and air fills the cylinder through the open intake valves. However, due to resistance in the pipeline and in the air cleaner, where the air is cleaned from dust, and a number of other reasons, the average pressure in the cylinder at the intake stroke will be less than atmospheric by 0.1-0.25 kgf / cm², which means that the air mass entering the cylinder will be slightly less than the maximum possible.

The mass of air decreases, in particular, with a decrease in the density of the outside air, which changes with increasing altitude and temperature. To ensure the most complete combustion of fuel, it must be supplied to the cylinder in an amount determined based on the actual mass of air in the cylinder at the end of the intake stroke.

Increasing the amount of fuel burned in a cylinder per cycle is the primary means of increasing engine power. The required increase in the mass of air entering the cylinder is carried out by installing a supercharger on the intake line, which supplies air to the cylinder at a pressure exceeding atmospheric pressure.

The compression stroke occurs when the piston moves upwards from Nm: t. to v.m.t. The intake and exhaust valves close and the air in the cylinder begins to compress. By the end of the compression stroke, the pressure in the cylinder reaches 35–42 kgf / cm², and its temperature rises to 500–600 ° C; in supercharged engines the air parameters are 45–64 kgf / cm² and 900–1000 ° С, respectively. The specified temperature is sufficient to ignite the fuel, and therefore at this time it begins to be sprayed into the cylinder. Mixing with air, fuel forms a working mixture that ignites spontaneously. By the time the piston arrived at the vm.t. an intensive process of fuel combustion begins.

The pressure in the cylinder of a naturally aspirated engine rises to 70-85 kgf / cm², and the temperature rises to 1700-1900 ° C. In supercharged engines - 80-90 kgf / cm² and 2000-2300 ° C, respectively.

The expansion stroke occurs when the piston moves downward from the TDC. under the action of expanding gases pressing on the piston. By the end of the stroke, the gas pressure in the cylinder decreases to 2.5-3.0 kgf / cm², and the temperature drops to 800-1000 ° C.

The exhaust stroke occurs when the piston moves upward, when the exhaust valves are open and exhaust gases are ejected from the cylinder. As it moves, the piston cleans the cylinder of exhaust gases, pushing them out. This completes the working cycle and the cylinder is again prepared to receive a portion of fresh air, i.e. a new working cycle can begin.