Characteristics Study On Light-Weight Single Cylinder Direct Injection Diesel Engine In Cylinder Flow

After the industrial revolution, human beings consumed non-renewable energy in the past one hundred years, resulting in a shortage of energy and environmental degradation and other issues. Diesel engine is a link to promote the progress of human civilization, so developing a more economical and environmentally-friendly diesel engine with a strong momentum has a great prospect. For the direct injection diesel engine, airflow in the cylinder and the formation of gas mixture play a crucial role to the combustion and pollutant emissions. Although the electronic control technology can provide the best fuel injection quanlity according the working conditions of the engine. And the injection pressure is not affected by the engine speed. However, as the hard work environment and high maintenance cost and other factors, the small single cylinder non-road agricultural diesel engines is improved by the improvement of the air flow in the cylinder and the quality of the fuel mixture in order to improve the power and economy of diesel.Due to the lightweight design of the GD190 single cylinder diesel engine, the cylinder head is very small. It is convenient to design the cylinder head through estimating the basic parameters of design. In this paper, we estimate the size of the injector nozzle at the first. The calculation model of injector and combustion chamber was established by ESE modular of AVL Fire. Then we establish the full model to analyse the influence of nozzle angle, nozzle depth and combusition chamber bias on combustion.The results show that the short stroke of high-speed single cylinder diesel engine need the injector with larger nozzle angle and the installation depth of the injector with deeper to be matched under when the injection pressure, the diameter of nozzle and the combustion chamber is not changed. When the nozzle angle is too small, the tangential force of the oil beam can not be matched with the air flow in the annular inflow combustion chamber from the cylinder to form a vortex which is beneficial to the atomization of the fuel vapor. When the installation depth of the injector is small, the fuel vaper is easily attached to the top of the cylinder head. And it is not conducive to combustion. We design a combustion which offset the piston center 5mm. But we do not change the injector model and the injector is installed in the center of the combustion chamber. When the diesel engine is full load of 2600r/min, the simulation results show that the atomization in the bias diesel engine combustion chamber is not uniform and the airflow changes a lot in the cylinder. The test results show that the fuel consumption of the offset combustion chamber is much higher than the non-offset combustion chamber under the condition of high speed and high load.