Stop-Start Technology Integration: Challenges, Controls and Fuel Economy Demonstration for City Bus Application in India 2021-26-0055

India has leapfrogged to BS-VI OBD-A emission regulations since April 2020 and is heading towards BS-VI OBD-C implementation by April 2023. The Fuel Economy (FE) improvement for heavy commercial vehicles is mandated through enforcement of Heavy-Duty Fuel Economy Norms (HDFE-I by April 2021, HDFE-II by April 2023) as part of BS-VI regulation in India. This is navigating the commercial vehicle industry to explore various technology options to improve FE. Commercial vehicle applications such as City Buses and Mining Tippers have long engine idle durations either due to traffic conditions or loading-unloading pattern. This makes engine idle control and specifically Stop-Start Technology a more viable and attractive option for FE improvement. The current paper provides an overall approach and details related to Stop-Start technology integration at engine and vehicle level. A real-world city bus duty cycles representing Urban City Traffic have been analyzed in detail for number of stop-start events, idle durations and potential fuel economy improvements. Specific integration challenges at system level are highlighted along with design changes, control logic, diagnostics, inhibits and interlocks. Design changes needed at components level are explained. Verification and validation tests needed at components, engine and vehicle level are presented in-line with Cummins global experience. Boundary Diagram, P-Diagram and FMEA (Failure Mode and Effect Analysis) tools have rigorously used to capture the failure modes and technical risks. Experimental results from a proof-of-concept (POC) vehicle trial in urban traffic conditions are also presented. The scope for future improvements in the Stop-Start technology integration aspects are also highlighted.