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Electronic control unit for high pressure common rail system diesel engines
Abstract
An electronic control unit (ECU) for high pressure common rail system diesel engines based on Motorola MPC555 is introduced. Using high performance microcontroller MPC555 and adopting schemes of modularization the hardware and fundamental software of the electronic controled unit (ECU) were set up. The hardware is made up of the micro controled unit (MCU), power, input and the output module. The software includes that of initialization, sampling, and outputting module. With this ECU, experiments on rail pressure control and fuel quality at different pulse and rail pressure were carried out, and do some MAP studies on start of injection (SOI) and rail pressure on engine test bench. Experimental results proved that this system can obtain quite fine effects in control.
Studies the rail pressure controll strategy and control parameters optimization of high pressure common rail diesel engine. Pressure control valve's specialities and control parameters are analyzed. Influences of the single control frequency, pressure sampling period and the loop control interval period for rail pressure control are studied. Control strategies of target set-point rail pressure value and corrections at different working conditions are designed. And the rail pressure sampling, controlling and corrections strategies are tested on engine test bench. It was proved that the pressure sampling, controll strategies could control the rail pressure at any value on any engine working conditions, and fulfill the needs of the common rail diesel engine.
To facilitate the calibration process of electronic-controlled injector, a study on the calibration of fuel quantity and buildup of basic MAP was made. Chief factors affecting fuel injection consistency and identity were analyzed. A method for fuel injection consistency and identity improvement was designed by controlling the common rail pressure fluctuation and modifying the fuel injection pulse. The initial fuel injection MAP was achieved by the method of variable step interpolation, then the accuracy of the basic fuel injection MAP was tested. A test on an engine equipped with the calibrated common rail electric control injection system was carried out. The experimental results proved the rationality of the initial fuel injection MAP.
A fuel injection control strategy for high pressure common rail diesel engine was designed based on the electric control unit (ECU) with the high performance microcontroller MPC555. The contro1 software was designed by modularization method according to various operation conditions of diesel engine. The software modules included the fuel quantity control module, rail pressure control module, management module for point of engine operation (POP), four stage start procedure control module, fault handling module and so on. By analyzing the frequency and importance of the POP, the control MAP was designed by using variable step and equal step. Finally, the experiments were conducted on test bench to verify the feasibility and reliability of the control strategies and to optimize the emission performance of the engine. Experimental results show that the expected control effect is achieved and the engine can reach the EURO-III emission standard.
A smart injector drive program combined software and hardware was proposed which was based on the Infineon TC1766 microcontroller layered architecture and rich peripheral modules. The software and hardware architectures of the program were described in detail. The injector drive module based on the architectures was the core of the self-research of common rail diesel engine ECU. The engine experiment results indicate that the smart injector drive program is of strong flexibility, high performance/price ratio and high drive current stability, and it can also meet the requirements of multiple injections in fuel system. ©, 2015, Chinese Society for Internal Combustion Engines. All right reserved.
The driving mode of Peak & Hold current shape is adopted in common rail diesel electronic control injector driving circuit. The requirements of current change are different in different stages. In order to meet the changes in the injection process, the state responses characteristics of the circuits to optimize the circuit and improve the response speed of electronic valve were analyzed theoretically. The driving circuit was designed based on the bootstrap circuit. The results showed that the fluctuations amplitude of the current in the hold stage reduced by 50% under the same driving parameters in the optimized circuit, and the response time was only 20 μs in the injector closing process, which realized the purpose of precise control of the injection quantity and injection timing.
In order to meet the EMC requirements of the vehicular engine control unit, a new design method of vehicular engine control unit is proposed. This method is based on the EMC analysis and simulation which includes board level and the line level simulation. The simulation results show the influence factors for ECU EMC performance, such as circuit arrangement and shell shielding. The vehicular control unit is designed by considering the above factors. The EMC experiment result shows that the EMC Analysis and design method is valid and can be a method to improve the ECU electromagnetic compatibility.
A rapid control prototyping based on torque control algorithm using V-cycle mode for common rail diesel engine was developed, and a torque prediction model was present which including a feed-forward mean value engine model and a feedback correction of error caused by the feed forward model. Finally, experiments were carried out on test bench to verify the control feasibility and reliability of the strategies and optimize the emissions, Experimental results showed that the anticipated control effects were achieved and the engine reached the EURO-III exhaust emission standard.
The main objective of this study is to develop the injection control strategy for high pressure common rail diesel engine based on the Electronic Control Unit (ECU) with the micro-controller MPC555. The control software was designed by modularization method according to various working conditions of diesel engine. The software modules include the fuel quantity control module, rail pressure control module, point of the engine operation (POP) management module, four stages of the start procedure control module, and so on. Finally, experiments were carried out on test bench to verify the control feasibility and reliability of the strategies and optimize the emissions, Experimental results showed that the anticipated control effects were achieved and the engine reached the EURO-square exhaust emission standard.