Efficiency benefits of flexible cylinder deactivation using a novel intake valve system

Abstract

Cylinder deactivation improves part load fuel economy in spark-ignition engines by reducing pumping losses. The efficiency benefits of a new intake valve system that enables flexible deactivation of different cylinders are investigated in this study. The intake valve system involves two intake valves in series, with a fast solenoid-actuated valve upstream of a conventional cam-actuated intake poppet valve. Compared to conventional cam-actuated variable valve timing, the new valve system has potential to achieve a high degree of flexibility in respect of the timing of inlet valve closure, while requiring lower actuation forces than fully-flexible valve actuation systems that act directly on the poppet valves. The fuel economy benefits provided by a number of valve control strategies are evaluated using a one-dimensional modelling approach, considering a vehicle following the New European Drive Cycle. Use of the intake valve system to control load by deactivation of different percentages of firing strokes is predicted to offer a very substantial improvement in fuel economy, achieving as much as a 43% fuel saving over the New European Drive Cycle compared to throttled engine operation. Use of flexible cylinder deactivation also affords fuel savings and thermal management benefits compared to more conventional cylinder deactivation schemes in which a fixed subset of the cylinders, typically one half, are deactivated at one time. The use of the valve system to make fine adjustments to the intake valve closure timing, as opposed to deactivation, is also discussed.

More information

Identifiers

ORCID for E.S. Richardson: orcid.org/0000-0002-7631-0377

Catalogue record

Export record