IAV brings variable valvetrains to heavy duty

Variable valve actuation, especially timing, has been readily available for light passenger engines for years. Problems in introducing the technology to heavy-duty diesel engines include the vastly different thermodynamics at play and the durability required. With already high compression ratios, clearance between the piston and valve in diesels can be an issue. Since a diesel is typically unthrottled, it is more difficult to improve efficiency compared to a gasoline engine. Constant switching in engines that run continuously means building reliable gadgets that can run for thousands of hours.

However, with the continued push for both fuel efficiency and criterion emissions control, IAV thinks it is time for heavy-duty applications to consider it. An engine with a fixed valve lift and timing must balance high-speed engine performance and low-speed fuel economy. Low speed and cold start exhaust temperatures also affect aftertreatment devices, especially important as regulatory pressures continue.