Junxi Wang

Start-of-injection-based software optimization for consistency between the cylinders in common-rail diesel engines

A common-rail system is widely used in electronically controlled diesel engines and has been used in Euro IV diesel engine development, as its consistency between the fuel injection quantities of the injectors can be controlled accurately. In Chinese home-made common-rail systems, the bottleneck is mainly caused by the mechanical manufacturing, which results in variation in the fuel injection quantity of different injectors. In spite of the low-class hardware limit, this paper introduces a software method to correct the inconsistency between the fuel injection quantities of the injectors over the whole range during which the engine is running. First, the main factor affecting the inconsistency between the fuel injection quantities of the injectors is determined on the basis of a series of experiments. Second, an optimization algorithm based on the start of injection is proposed to compensate for the difference between the injectors. Finally, the algorithm is verified on an EFS 8246 fuel-pump-testing platform and further on a YC6A diesel engine. The experiments demonstrate that the correction based on the start of injection not only can reduce the inconsistency between the fuel injection quantities of the injectors but also can improve both the idling control and the emission performance for the electronically controlled diesel engine. This paper also provides a successful example for improving the consistency between the fuel injection quantities from cylinder to cylinder in an electronically controlled diesel engine by this software optimization method.

Principles and application of the real-time hardware-in-the-loop simulation platform based on multi-thread and CAN

This paper introduces the principles, construction and application of a novel real-time hardware-in-the-loop simulation (RT-HILS) platform. The RT-HILS consist of a PC to display the simulation result and calculate the model, a HIL board to generate the analogue signals and measure the output of the target ECU, and a USB-CAN card to implement CAN (controller area network) communication. Multi-thread technology is used to control the modelspsila calculation step to guarantee its real-time characteristics. The CAN with the speed of 500 Kbit/s is also important to real time simulation. The models and communication functions are cooperated into the LabView by its DLL node. The RT-HILS platform has applied to the diesel engine controller and hybrid vehicle controller. An example of the application of RT-HILS to the development of HCU (hybrid control unit) is presented to show the functions of RT-HILS.

Development of a new hardware-in-loop simulation platform for GD-1 diesel engine based on CAN and multithread technologies

A new scheme was adopted in the hardware-in-loop (HIL) simulation platform adopted to develop simulation ECU and monitor-control interface. Hardware design: The simulation ECU was developed with the 32-bit single chip MC68376 of MOTOROLA, which converted and sent all necessary parameters for electronically controlled diesel ECU (object ECU); An accurate measurement was achieved to actuator signals with no-contact current sensors. Software design: The high efficiency of assembly language and the convenience of c language were combined to realize simulation ECU control program; The multithread technology was used in PC control program, and there were 3 threads: a monitor-control interface thread, a diesel model thread and a communication thread. Labview was used to develop the monitor-control interface as main thread, and diesel model and communication threads were programmed by C+ and ran in the background as sub threads. Communication: CAN bus communication protocol was adopted and communication programs were developed separately for TouCAN module and USBCAN, communication data is converted with an USBCAN intelligent conversion card and an accurate, reliable and quick communication was achieved between simulation ECU and PC, with baud rate up to 500 kbit/s. This platform has been successfully used to develop HIL system for GD-1 high pressure common rail electronically controlled diesel engine and Delphi EUP (a little changed).

Controller Design and Emission Improvement for Lean-Burn CNG Engine Based on UEGO Controller

The configuration and driving principle of Universal Exhaust Gas Oxygen sensor (UEGO) was introduced. Based on the technology of Electronic Pressure Regulator, the system structure of Compressed Natural Gas (CNG) Engine is built. Based on the chip MPC 561 and integrate chip CJ125, the UEGO controller which include hardware design of UEGO driver and software design of Air-fuel ratio closed loop are designed. Based model and PID controller, the control strategy of Air-fuel ratio closed loop is discussed. Bench tests show that the operating temperature of UEGO is stable and the response of UEGO driver circuit is rapid and accurate, and error of steady-state is small. This system will reduce the CNG engine’s fuel consumption and emission. Based of the UEGO control system, the intelligent control of engine’s intake rate of air and emission could be achieved.

Engine Operation Control for an Electromagnetic Coupling Dual Electric Machine Hybrid Electric Bus

An electromagnetic coupling dual electric machine hybrid electric bus is investigated. The flywheel and start-motor of the Internal Combustion Engine (ICE), the mechanical clutch and the manual transmission are replaced by Double-electric Machines (DM). The DM work as an electromagnetic clutch and a continuously variable transmission, simultaneously. An Improved Engine Operation Control (IEOC) is proposed to maximise the efficiency of the overall electromagnetic coupling system, in which the ICE efficiency, the DM efficiencies and the battery efficiency are all explicitly taken into account. Simulation results indicate potential fuel economy improvement relative to the traditional control.

Development and performance validation of an ISG diesel hybrid power-train for city transit buses - part I: Parameter matching and system integration

This two-part paper presents the development an ISG diesel hybrid power-train to provide a solution for the city transit buses. The ISG power-train which adopts the ISG parallel configuration which is inserted a thin but powerful motor between the engine and the flywheel is a compact and flexible power-train with high efficiency and sufficient power. The drive demand of Chinese typical city cycle is analyzed and the key componentspsila parameters are deduced using the classic vehicle dynamic equation. The design of permanent magnetic motor and its controller are introduced in details and the system integration is illustrated as well. The control system and the multi-energy strategy that are the key to realize the fuel economy target will be introduced in the part II. The bench test of ISG diesel power-train is conducted to test the maximal performance and to validate the functions of ISG motor.

Application of circuit simulation in hardware design for Electronic Control Unit of Compressed Natural Gas engine

Based on V-type development method and circuit simulation, an electronic control unit (ECU) of compressed natural gas engine is designed. Circuit simulation is discussed in detail. According to system requirements for Hardware of ECU, ignition drive circuit, signal sampling and processing circuit and power module are simulated in emphases. Based on multi-thread technology, Hardware in loop test system is also designed. This CNG ECU is applied in bench test successfully. Results of hardware in loop test and bench test showed that hardware meets the requirement of CNG control system. Circuit simulation and V-type platform can greatly increase the quality of hardware design, alleviate design labor and shorten design time.