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Current concerns about climate change, energy security and record high oil prices have triggered high enthusiasm and push for plug-in vehicles. Widespread adoption of plug-in vehicles would result in significant reductions in CO2 emissions from transportation. It would also reduce our dependence on fossil fuels by replacing petroleum-sourced energy with renewable, domestically produced electricity. While a few OEMs have successfully launched hybrid vehicles and even toyed with plug-in hybrid solutions in the passenger car market segment, little attention has been placed on heavier commercial vehicles. Large utilities operate fleets of several hundred diesel-power trouble trucks to repair and maintain their transmission and distribution infrastructure. Medium-duty segment is over a million vehicles annually. These vehicles are typically driven in densely populated neighborhoods.

The SAE Fuel Cell Vehicle (FCV) Safety Working Group has been addressing FCV safety for over 9 years. The initial document, SAE J2578, was published in 2002. SAE J2578 has been valuable as a Recommended Practice for FCV development with regard to the identification of hazards and the definition of countermeasures to mitigate these hazards such that FCVs can be operated in the same manner as conventional gasoline internal combustion engine (ICE)-powered vehicles. SAE J2578 is currently being revised so that it will continue to be relevant as FCV development moves forward. For example, test methods were refined to verify the acceptability of hydrogen discharges when parking in residential garages and commercial structures and after crash tests prescribed by government regulation, and electrical requirements were updated to reflect the complexities of modern electrical circuits which interconnect both AC and DC circuits to improve efficiency and reduce cost.

The SAE Fuel Cell Vehicle (FCV) Safety Working Group has been addressing FCV safety for over 10 years. The initial document, SAE J2578, was published in 2002. SAE J2578 has been valuable as a Recommended Practice for FCV development with regard to the identification of hazards associated with the integration of hydrogen and electrical systems onto the vehicle and the definition of countermeasures to mitigate these hazards such that FCVs can be operated in the same manner as conventional gasoline internal combustion engine (ICE)-powered vehicles. An update to SAE J1766 for post-crash electrical safety was also published in 2008 to reflect unique aspects of FCVs and to harmonize electrical requirements with international standards. In addition to SAE J2578 and J1766, the SAE FCV Safety Working Group also developed a Technical Information Report (TIR) for vehicular hydrogen systems (SAE J2579).

An advanced Variable Valve Actuation (VVA) system is optimized for response time in order to provide robust switching at high engine speeds. The VVA system considered is Cylinder Deactivation (CDA) for the purpose of improving fuel economy. Specifically, a Switching Roller Finger Follower (SRFF) on a Dual Overhead Camshaft (DOHC) engine is optimized for cylinder deactivation. The objective of this work is to (1) improve the latch response time when the system response is the slowest, and (2) balance the “ON” and “OFF” response time. A proper tradeoff was established to provide the minimum switching time such that deactivation and reactivation occurs seamlessly and in the right sequence. The response time optimization is accomplished while maintaining the existing packaging space of the overhead. A camshaft with a single lobe per SRFF device on a type II valvetrain was used as the baseline configuration for this study.