Research Of Gaseous-fuel Engine Intake System Based On CAN-Bus Technology

Recently, environmental improvement and energy issues have become more and more important as worldwide concerns. Natural gas is a good alternative fuel to improve these problems because of its plentiful resources and clean burning characteristics. At present, the major two problems with gaseous-fuel engine are as follows: first the main gas supply mode is mechanical gas mixer, this mode has low air-fuel ratio control accuracy and lower volumetric efficiency due to air volume occupied by gas; second, because of changes in gas composition and an uneven air distribution of mixture to cylinders, the power is different cylinder-by- cylinder. These two reasons make engine power loss and fuel consumption increase.In order to solve these problems, in this paper a new gas supply mechanism is propose based on intake manifold injection mode by analyzing a variety of gas supply mode. The mechanism is a valve droved by stepper motor, which can achieve gas supply by valve open and close. It also can adjust the supply time and supply quantity of gas. Moreover, with low cost, and less technical difficulty, so the mechanism has some practical values. For realize this purpose, the main jobs of this paper are as follows:(1) Based on 12V190 gaseous-fuel engine, the one-dimensional BOOST model were set up, to provide conditions for further analysis the difference of mixture to cylinders and drafting the control strategy;(2) For the intake manifold system of 12V190 engine, carried out three-dimensional numerical simulation. the uneven air supply is carried out with intake manifold structure and intake manifold pressure wave by numeration; The results show that, the structure have a little influence on the uneven air distribution. The intake pressure wave produced by mutual interference has more influence on the uneven air distribution;(3) When use intake manifold injection mode for supply gas, the gas quantity must be controlled independently because of the difference of quantity of gas supply, if not, the power difference cylinder-by-cylinder would exist. This paper developed distributed control system based on the CAN-Bus technology, so that the gas quantity can be controlled independently;(4) Finally, the control strategy of gas supply system is researched, and the feasibility of the control system is verified through simulation experiment.