An Investigation on the Effect of Variable Valve Timing on Piston Engine for Lightweight Aircraft

Abstract

As the Lycoming engine had failed its attempt on using variable valve timing for aircraft piston engine back in 1940s, the idea of the technology was abandoned as the turbines were then introduced in the aviation for better performance and greater power. Since piston engines produce smaller power efficiently in the low speed than turbine engines, they are presently still practically used in most of lightweight aircraft. With the use of a variable valve timing mechanism, it may help to increase the amount of air inlet and to provide more power output with lesser fuel consumption. With the use of this new valve system, improvements in the performance of automobile engines have been recorded. The indicated improvements, however, are limited to automobile engines running with high revolutions only. Engine simulation program was run in this investigation as an attempt to predict engine performances that are appropriate for lightweight aircraft.

The Influence of Valve Timing on in-Cylinder Pressure Spark Ignition Engines Performance Characteristics

“…The crank angle degree (CAD) represents the timing of the engine crankshaft and directly drives the camshaft which manages the intake and exhaust valve timing and lifting. The cam timing of opening and closing valves is determined by valve lift profile trends [18]. Cam timing angle (CTA) is used to control the location of maximum valve lift.…”

“…According to Pauras [11] the simulation software used is Ricardo Wave for the study of valve timing. However, less information has been given to investigate the relationship between valve timing to in-cylinder pressure of fuel injection of a spark-ignition engine [12], [17], [18], [11]. As a result, the lack of thorough study makes it difficult to study the effect of valve timing in detail.…”