Fault Management Strategy and PWM Monitoring for HVAC ECU

Abstract

Driver Interface is an electronic control unit (ECU) which has display and control features. Driver Interface ECU s include ECU s like Integrated Center panel (Radio interface control and HVAC interface control), HMI and Steering wheel control(SWC). Lets consider HVAC (heating, ventilation air conditioning) ECU. It is an air conditioning module which takes inputs from CAN and LIN communication bus, buttons, sensors and touch screen. It also has output lines to control in car temperature, fan speed and air distribution etc. Hardware input output lines are designed to be protected from unusual voltage and current failures. There are many scenarios to be verified to assure that protection design requirements(Fault management requirements) are effectively working. Currently these verification scenarios of ECU are done manually. There is a need to design automation to verify fault management requirement quickly and effectively. HVAC ECU also controls air inlet and air distribution in the vehicle through stepper motors. Stepper motors move as per the command from user interface (push buttons) or communication bus. Automation has to be developed to measure the stepper motor movements. Above automations are planned to develop using NI PXI (Peripheral extension of instrument) and NI LabViewalong with signal conditioning circuits. NI PXI will have cards to simulate and measure analog, digital lines and communication bus. LabViewis the IDE (integrated developing environment) to program the PXI cards for the above need.