WCET analysis for gasoline engine control

An architecture and worst-case execution time (WCET) analysis is proposed for vehicle real-time control unit. In the WCET analysis, modeling, scheduling and verifying are implemented. This paper investigates into single cylinder gasoline engine control system, which is featured by complex state-varying temporal parameters. The worst case happens when engine speed increases to maximum. For timing analysis, a coordination transformation from absolute time axle to crankshaft rotational phase is applied. The established workload model includes six tasks distributed on three processors. An updated triple as [P E d] is defined to specify temporal parameters, and an interconnection graph is compiled to describe the timing and resource dependency explicitly. A local nonpreemptive timer-triggered (LNPTT) scheduling algorithm is designed and verified in terms of feasibility concerned both prerequisite and sufficient conditions. Simulations and experiments for LNPTT, compared with round-robin scheduler, are implemented. The results show, the established real-time model is suitable for WCET analysis, and LNPTT is feasible and reliable for gasoline engine control system, while round-robin scheduler is unreliable for this issue.