The difference between the excess air coefficient of a diesel engine and a gasoline engine

The excess air coefficient is the ratio of the actual amount of air supplied to the amount of air required to theoretically burn 1kg of fuel completely. The upstairs is not correct, and the bigger the coefficient, the better it must be wrong. Theoretically, it is desirable to have complete combustion, that is, an excess air coefficient of 1, but this does not guarantee that it will be completely burned in actual operation, so the amount of air is increased during actual operation to achieve the purpose of complete combustion, and even then it cannot guarantee that the fuel will be burned out.

The diesel engine belongs to the mixed cylinder, and the fuel is injected into the combustion chamber before it is mixed with the air, and the gasoline engine belongs to the premixed combustion, and the fuel and air are pre-mixed; The excess air coefficient of diesel engines is greater, because it is more difficult to ensure the mixing of fuel and air in the cylinder in the case of non-premixing, which often leads to a large air-fuel ratio in some places and a small part. Compared with gasoline engines, diesel engines are large and complex in structure, of course, with high efficiency and high horsepower.

The excess air coefficient is the actual air quality supplied by burning 1kg of fuel and the theoretical air quality required to burn 1kg of fuel completely.

Under normal circumstances, the excess air coefficient of the gasoline engine is strictly controlled at about 1, because the three-way catalytic reactor requires the excess air real number to be strictly about 1.

The excess air coefficient of the diesel engine is greater than 1, this is because the diesel engine is diffusion combustion, and the formation of the mixture mainly depends on the spray quality, in order to ensure combustion, a large excess air coefficient is required. The excess air coefficient is different depending on the combustion chamber, and even under heavy loads, the excess air coefficient is greater than 1

Dear, hello, very high model selling for you to answer, the diesel engine empty code air intake is how much normal air intake: 1, this is not accurate, the air intake of different displacements is not uniform, it depends on how many gears are hung, and the air intake of different gears is not the same; 2. If you want to give the normal air intake, then look at the diesel engine displacement to calculate, most of the car air intake is 1000-1500g s is normal; 3. The air intake volume refers to the flow rate of the engine into the fresh air outside, and it is the oxygen that enters the engine when it is working, so as to ensure normal operation; 4. The accurate estimation of the air intake volume of the cylinder under the transient working condition is one of the effective measures to improve the accuracy of the air-fuel ratio control of the engine.

Increased resistance of the intake and exhaust system The air filter is not maintained in time, and there is too much carbon accumulation in the intake and exhaust pipes, mufflers and valves. Some operators arbitrarily lengthen the intake and exhaust pipes, so that the intake and exhaust resistance increases, the fresh air entering the cylinder is reduced, and the inflation coefficient is reduced. Prevention method:

Strengthen the maintenance of the air filter, remove the intake and exhaust pipes, mufflers and valves in time, avoid arbitrarily lengthening the intake and exhaust pipes, keep the intake and exhaust systems unblocked, and reduce the intake and exhaust resistance. 2.Diesel engine operating temperature is too high due to engine overload for a long time, cooling system failure or late oil supply time.

Due to the reason of thermal expansion, the density of gas decreases, so that the air intake of the cylinder decreases and the inflation coefficient decreases. Prevention methods: First, avoid long-term overload operation of the engine; The second is to pay attention to the inspection and maintenance of the cooling system, and eliminate the fault in time; The third is to maintain good fuel injection quality and normal fuel supply time.

3.The engine runs at low speed or high speed for a long time Because the gas distribution phase of the engine is generally determined according to the calibrated speed, the air flow speed is slow when running at low speed, the flow inertia is small, and the gas distribution phase is not compatible, and the gas backflow phenomenon will occur at the end of the air intake, therefore, when the speed is lower than a certain value, the inflation coefficient decreases with the decrease of speed. However, when the rotational speed exceeds a certain value, the higher the rotational speed, the faster the airflow speed, and the greater the intake and exhaust resistance, resulting in a decrease in the inflation volume and a decrease in the inflation coefficient.

Therefore, it is necessary to choose the engine load reasonably so that the engine runs at the most favorable speed.