ADI APPLIED DYNAMICS INTERNATIONAL. Electronic Engine Controller Development Using Open Architecture Development Tools

Transcription

1 Electronic Engine Controller Development Using Open Architecture Development Tools

2 Electronic Engine Controller Development Using Open Architecture Development Tools The engine control system and its calibration is often the key enabler for the introduction of new engine technology. The sophistication of engines and their control strategies continue to increase in the pursuit of lower emissions, reduced fuel consumption and improved performance. The engine control system and its calibration is often the key enabler for the introduction of new engine technology. Advanced control strategies incorporate an increased amount of engine operating data such as combustion feedback using ion current or cylinder pressure. By incorporating more information into the control strategies, the engine controller is able to compensate for production tolerances and component aging to obtain an improved balance of emissions, economy and power. The development of modern engine control units (ECU) is a highly parallel activity. Control algorithms are typically first developed using closed-loop desktop simulation. Control algorithm development is performed in parallel with design and development of the engine itself. Closedloop desktop simulation provides a low-cost arena for developing and testing control algorithms and software. Parallel engine control development tasks 1

3 HIL simulation enables the real electronic interface between the engine and the ECU to be included early in the development process. As early engine simulations and early versions of the control algorithm become available, hardware-in-the-loop (HIL) simulation using a rapid prototype controller begins. HIL simulation serves two main purposes: 1. It provides a platform where control software can be developed in real-time using a rapid prototyping controller 2. It provides a platform where software can be tested in real-time with production ECUs and acceptance testing may be performed on future versions of the ECU HIL simulation enables the real electronic interface between the engine and the ECU to be included early in the development process. Electronic interface resolution has an impact on the performance of the closed-loop system. Assessing this impact early in the development process reduces project risk by allowing more time to make algorithm design iterations. Rapid prototyping controllers are a powerful tool for ECU development. The use of a rapid prototyping controller serves two main purposes: 1. Provides a real-time prototyping tool where controller software may be tested with real electronic interfaces 2. Enables closed-loop testing with the real engine to occur before production ECUs are made available Production ECUs are commonly a critical path item in engine development projects. Use of a rapid prototyping controller enables work to be completed well before the ECU is made available. In addition, rapid prototyping ECU normally provide a higher level of visibility into the inner working of the controller software to assist development test and debugging. 2

4 Rapid Prototyping with the Ricardo rcube Conventional automotive calibration tools can be linked to the rcube using Control Area Network (CAN) or the NEXUS port. The Ricardo rcube rapid prototyping controller is a generic control system that has been applied to engine, transmission and other vehicle control functions. The main features of rcube are: >500MIPs processing power from 2 PowerPC microcontrollers Memory 16MB Flash ROM and 96MB RAM Powerful development environment includes support for autocoding Automotive I/O with integrated power drivers Automotive temperature range and IP66 sealed housing Simulink and ASCET-SD compatible Current and recent projects that have been enabled by the rcube include: Twin variable valve timing/lift engine control Advanced automatic transmission control Cylinder pressure based engine management systems Two-stroke/four-stroke engine control The engine control strategies running on the rcube are taken from existing Ricardo engine control Simulink libraries. These strategies were graphically linked to the Input/Output Applications Programming Interface (API) and auto-coded using Real Time Workshop (RTW) to run on the rcube. One of the Ethernet ports on rcube can be used to monitor the control strategies in the Simulink modeling environment using Simulink External Mode. In addition, conventional automotive calibration tools can be linked to the rcube using Control Area Network (CAN) or the NEXUS port. In the demonstration provided, INCA is used to monitor and calibrate the engine control strategies over CAN using CAN Calibration Protocol (provided as standard). The rcube provides flexible interfaces for developing and calibrating control strategies rcube rapid prototyping controller 3

5 Engine HIL Simulation with the rtx Powertrain The Simulink mode, all I/O, real-time scripting, and data logging were executed in less than 100us. An rtx Powertrain, PC-based real-time simulator was used in this application to provide realtime simulation of an 8-cylinder, spark injection engine. The rtx-sx was chosen which includes a single 3GHz Intel Pentium 4 processor. The processing power provided by this real-time computer enabled the Simulink engine model, all I/O, real-time scripting, and data logging to be executed in less than 100 us. More demanding real-time simulation applications may warrant the use of the higher performance rtx-px which includes a higher performance 2.4GHz AMD Opteron processor or the rtx-dx which includes two tightly integrated 2.4GHz AMD Opteron processors. HIL project setup with rcube controller A Simulink engine model, supplied by Ricardo Inc., was used to simulate an 8-cylinder, dual-bank, naturally aspirated, spark ignited, multi-port fuel injected engine. The model includes wide-range oxygen sensors for each bank of the engine and pre and post catalytic converter for a total of four oxygen sensors. The real-time simulation project was developed using the ADvantageDE development environment included in the ADvantage simulation framework. ADvantageDE enabled the Simulink engine model to be added to the real-time project with little effort. By selecting the -rtx template in Simulink RTW, the generated C-code was ready to run on the rtx. The ADvantage simulation framework includes the use of a data dictionary. The data dictionary documents all simulation variables, model inputs and outputs, signals, and block parameters. The value of a data dictionary entry may be viewed or changed (if writable) at any time that the simulation is loaded or running. ADvantageDE automatically generates a data dictionary for each Simulink model in the real-time simulation by analyzing the model. 4

6 Simulink engine model supplied by Ricardo Inc. Real-time signals in the rtx are provided using standard, off-the-shelf PCI boards. A range of engine-specific, real-time signals are used in this controller development project. The standard rtx Powertrain includes an extensive collection of signals for performing real-time simulation of various engine configurations using various sensors types. This project used a subset of the available signals. Real-time signals in the rtx are provided using standard, off-the-shelf PCIboards. Boards may be added to the system as needed and in the event that a project requires more signals than will fit in a base rtx, an expansion box may be used to extend the PCI-bus and increase the slot count. The majority of signals were provided by the PCI-Engine. The PCI-Engine is a 2 board set based on Motorola s MPC565 microcontroller. The PCI-Engine s processor board holds the microprocessor and has 3 IP daughterboard slots. Mounted on one of the daughter board slots was an IP- Digipat. The IP-Digipat provided Hall Effect sensor emulation for the digital cam and crank signals at battery voltage levels. Cam and crank angle resolution was 1/20th CA deg up to 14,000 rpm. Alternatively, the IP-Digipat may be replaced with an IP-Arb for analog VRS-style cam and crank output. The second board in the PCI-Engine s 2 board set includes signal conditioning and jumper selectable transceivers for the two CAN channels. In this project a CAN-based throttle position sensor was implemented using the high-speed ISO /J1939/J2284 transceiver. The PCI-Engine also provided the 8 spark and 8 fuel measurement channels for this project. 5

7 When performing real-time simulation of engines with more than 8 cylinders or 8 injectors, additional PCI-Engine boards may be added to the rtx and crank-synchronized using the high resolution crankshaft sync signal. Much of the PCI-Engine s functionality was unused for this project. The 8 channels PWM input, 8 channels PWM output, 2 channels stepper motor emulation, knock signal generation, and second CAN channel were not used for this engine configuration. HIL Simulation real-time signals The rtx Powertrain includes Ratiometric analog output channels using IP-3DAC IP modules. These analog signals were used to emulate the oxygen sensor, manifold absolute pressure sensor, and mass airflow sensor. Thermistors were handled in the system using the 8 channel PCI- Thermistor board. The control of battery voltage power to the ECU was handled in the system using a relay board. Model inputs and outputs are connected to the rtx I/O signals in ADvantageDE by appropriately naming signal ports and pressing the autoconnect button. The rtx Powertrain used for this project included a ConneXions Box specifically designed to mate with the turnkey powertrain rtx (Powertrain ConneXions Box). The ConneXions Box breaks signals out from the high-density cables and connectors used with standard PCI boards to terminal blocks, then maps these signals to standard automotive Elco connectors. The terminal blocks provided a convenient place for probing signals. 6

8 In addition, the ConneXions Box provides a place where loads may be added as necessary. Loads are commonly added to emulate injectors, spark plugs, and other electrical loads required by the controller. Current requirements for spark plugs are often limited at 9A with an operating range of 6 to 6.5A. In this project the rcube provides a totem-pole drive for spark. The totempole drive enables the rcube to be connected to the rtx without a load. The fuel injectors and fuel pump relay used a nominal 330ohm load mounted in the ConneXions Box. Injector and fuel pump relay loads mounted in the ConneXions Box The HIL simulation is loaded and controlled using the ADvantageVI tool included in the ADvantage real-time simulation framework. When a project is loaded, the ADvantageVI Windows application connects with the rtx real-time simulator over a TCP/IP network. Run-time simulation project files are automatically sent to the simulator, the initial memory values for model variables and parameters are queried, and the real-time simulation is ready to run. The Data Browser in ADvantageVI is used to browse the simulation model when loaded or running. Signals, parameters, and variables grouped in the data dictionary appear in organized folders. Run-time writable data dictionary entries may be controlled and any entry may be inspected from the Data Browser. Test control and interaction with ADvantageVI 7

9 Real-time scripting was implemented to build repeatable tests. The real-time scripting elements used for this project included schedules and triggers. Schedules are used to build up simulation control profiles of any level of complexity. These profiles are evaluated in lock-step with the model execution ensuring a high level of test repeatability. The ADvantage real-time simulation framework includes Altia for visualization and interaction. Altia enables virtual panels and animations to be created by dragging widgets from standard libraries. Software connections are made between the Altia widgets and simulation model variables using ADvantangeDE. 8

10 Two Altia panels were created for this project. The first panel provided basic engine stimulus for power moding, throttle, and cam phasing, and displayed engine temperature, RMP, lambda, and fuel. The second panel provided detailed display of engine operation including oxygen levels, map, tps, fuel rate, knock, rpm, ect, egt, and valve positions by Applied Dynamics International and Ricardo Inc. All rights reserved. ADvantage, ADvantageDE, ADvantageVI, rtx, and rtx Powertrain are trademarks of Applied Dynamics International. rcube is a trademark of Ricardo.