The Effect Of Gas Injection Position And Direction On Performance Of Natural Gas Engine

Economic development brings some problems like energy consumption and environmental pollution.Oil as the main energy,its reserves have been gradually depleted.Alternative energy,energy conservation and emission reduction are the focus of development.Burning natural gas with free of harmful substances and high storing levels is an advantage of alternative energy,and natural gas engine is the main force of emission reduction,with characteristics of high thermal efficiency and low NOx emission.With the escalation of emission regulations,higher thermal efficiency and lower NOx emission requirements continue to upgrade.And the cylinder needs to burn diluter mixing gas.In order to more stable combustion characteristics and higher thermal efficiency,it is necessary to explore the reasonable mixed gas reservoir in engine cylinder.Using a turbocharged multi-point injection electronically controlled natural gas engine,the test and control platform and numerical simulation platform are used to verify the key conditions of the CNG engine,such as ignition delay,flame propagation speed and so on.By making an electronic control device,changing the position and direction of the gas injection verify that if the inner layer of the mixed cylinder can widen the combustion limit.The research results show that:1.The process of natural gas entering into the cylinder is divided into two states,first of which is deposited in the bottom of the combustion chamber,and then in the middle and upper part,and the compressed combustion gas is mainly mixed with gas of the diameter.2.Under the equivalent injection of natural gas engine,changing the injection direction affects the time of mixing gas entering the cylinder and the distribution of the gas concentration in the cylinder.Natural gas is sprayed upwards,causing the gas to enter the cylinder at a later time.Down injection can quickly enter the cylinder through the airway.The left and right jets are based on the inlet shape and are analogous to the downward and upward jets.Therefore,the mixing gas concentration of the upward injection near the spark plug is higher,economic is better and NOx emissions is higher in the same equivalent and injection time.3.Using CATIA V5 modeling software,the design object is mixed modeling,intercept parameters and variables,motion simulation analysis.The device of electronically controlled gas injection position,the device of electronically controlled gas injection direction,the kinematic simulation analysis and the mechanism calculation are realized.4.The electronic control system device is composed of software platform and hardware platform.The hardware platform uses S12G48 as the main processing chip,and the peripheral auxiliary function circuit.The software platform uses Freescale CodeWarrior5.1,and the main programming language is C language.The system is designed to realize the controllable gas valve access channel.The valve channel consists of 1,2,3 and 4 channels.Open the specified valve according to the CAN bus command.At the same time,this system has the relay adhesion diagnosis,the valve drive motor working condition diagnosis,as well as the correlation diagnosis function,to satisfy the system security demand.