Research On Control Strategy Of LNG Engine

The main content of this paper is the research of the LNG engine control strategy.The control strategy of start,idle speed closed-loop and the throttle tunning of pedal condition,speeding-cut-off as well as engine stop condition were established.The control strategy in single point injection to multi-point injection of high power gas the engine was successfully applied.The use of self-developed natural gas injection valve,so that the engine performance can meet the requirements of the work.In this paper,the verification of control strategy and code functionality is mainly divided into the software-in–the-loop-simulation,the processor-in-the-loop simulation as well as rapid prototyping test.Software-in-the-loop-simulation is mainly in the Simulink environment test,the processor in the loop simulation is to verify the code in the target board to achieve the function and the consistency of the function under the simulation conditions.This article study the theory of the engine control strategy,and set up rapid prototype test,rapid prototyping test bench based on open ECU,and the verification results prove the effectiveness of the control strategy.In this paper,the control strategy is introduced into the rapid prototype of the project,a key to compile and write.Through the openECU own calibration tools,a number of variables and pulse spectrum can be pre-calibrated,so as to verify the functionality and accuracy of the strategy.In order to shorten the development cycle of ECU,reducing the matching test work,ECU calibration is used based on the CAN bus calibration protocol--CCP protocol,The calibration interface established by the CANape calibration tool realizes the measurement and calbration of parameters and MAPs,so as to realize the development and control function of the whole ECU.This paper designed the special test platform of engine electronic control system through a crankshaft sensor and camshaft sensor to measure the rotational speed of engine in different working conditions,and through a variety of analog sensor signals,such as inlet air pressure,boost pressure,cooling water temperature,inlet temperature,gastemperature,oxygen content,the effective strategies and ignition and output injector drive engine control is verified.The experimental results show that the control software can realize the precise control of ignition time,injection time and injection pulse width of natural gas.Finally,this paper through the engine bench test of multi point injection natural gas engine development test.In the engine bench test system,the starting conditions,idle speed,acceleration and deceleration and other conditions were calibrated,the basic fuel supply pulse spectrum,ignition advance angle and the main parameters of the calibration values were determined.The test results show that the engine achieves the intended target.