Increasing Torque Output from a Turbodiesel with Camless Valvetrain

In recent years sales of diesel-powered cars and trucks have increased dramatically worldwide. The efforts to raise specific power of diesel engines to allow for smaller and more efficient powertrains should include variable valvetrain technology.

Some benefits that might become available with application of camshaft-based variable-valve mechanisms have been studied in [1]. Significant progress has also been reported in the development of camless actuation mechanisms [2, 3]. To fully evaluate the torque improvement opportunities for light duty diesel, the authors have assumed that a camless valvetrain will become available in the future. This will provide the ultimate flexibility to choose timing and duration of valve events to maximize full load torque.

Simulation results revealed potential for a substantial increase in engine torque by optimizing the intake and exhaust valve timing together with turbocharger operation. However, improved turbocharger performance is needed, which is not available with current technology. Impact on fuel consumption, and containment of increased peak cylinder pressure are discussed.