Instrumentation and Processor in Loop Verification for Dynamic Skip Fire Technology 2019-01-1245
Amidst various cylinder deactivation technologies in automobile engines which provide better fuel efficiency, Dynamic Skip Fire (DSF) has proved to be quite promising. In DSF, a firing decision is made every crank angle event based on how much torque is requested. Providing this technology to automakers in form of a software package can be quite challenging given that there is little or no hardware access to a customer’s engine controller. The integration of the DSF software package with controller firmware can cause certain deviations in timing and performance depending on the platform and compiler being used by the manufacturer. In this paper, we discuss how we can closely emulate a development and testing environment and produce confident instrumentation and test results. To do so we use the same family of microcontrollers and compiler as that of the target controller and use an industry wide calibration and test software. Further, the timing data acquired from various functions in the DSF source code is analyzed in detail, with emphasis given to drive-train data as inputs to the system. The critical software issues are then easily identified before delivery to the target controller. A method for determining the computational time required for DSF is shown and advantages of this method are detailed. Further advantages of this procedure for testing and calibration are described and future extensions of this work are given in detail.
Arnav Mohan, Karthik Deepak Natraj, Joe Serrano