The diesel engine is inhaling pure air during the intake stroke. At the end of the compression stroke, diesel fuel oil injection pump will increase the oil pressure to more than 10MPa, through the injector injected into the cylinder, in a very short time with the compressed high temperature air mixture, forming a combustible mixture gas.
Because the compression ratio of diesel engine is high (generally 16-22), the air pressure in cylinder can reach 3 at the end of compression. 5-4.5MPa, at the same time the temperature is up to 750-1000k (and the gasoline engine at this time of the mixture pressure will be 0. $number. 2MPa, temperature up to 600-700k), much more than the ignition temperature of diesel, so diesel in the air after the injection into the cylinder, in a very short time after mixing with the atmosphere immediately
The air pressure in the cylinder rises rapidly to the 6-9MPA, the temperature also rises to the 2000-2500k, under the high-pressure gas impetus, the piston moves downward and drives the crank shaft to work, the exhaust gas is also discharged into the atmosphere by the exhaust pipe.