Improvement and optimization for eliminating post-combustion of a natural gas engine
LI Xiaodong
YOU Kai
XU Xiaoying
MA Junfang
Abstract：In order to solve the post-combustion problem of a natural engine,the bench test is carried out to analyze the ignition angle domain voltage,air-fuel ratio,cylinder pressure and actual gas mass flow rate of the main side and slave side electronic control unit(ECU),it is determined that the reason for post-combustion is that the slave side ECU calculate the delay by using the speed density method,which makes the transient air-fuel ratio being too small and the gas volume fraction being too large under transient conditions.Three measures are taken to improve and verify:adjusting the slave side charging efficiency,increasing the minimum throttle threshold to slow down the transient process,changing the gas mass flow rate of the slave side ECU from the speed density method to the throttle calculation method.The results show that the three methods can solve the post-combustion,adjusting the charging efficiency is only suitable for unloading all loads,slowing down the transient process leads to an increase in the torque unloading time,and changing the gas flow rate of the slave side ECU from the speed density method to the throttle calculation method is the best.
Keywords：post-combustionspeed density methodthrottle calculationair-fuel ratio
Publication Date：2025-01-30
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：6( 45-50 )