Seethaler, R., Koch, C., Chladny, R., and Mashkournia, M., "Closed Loop Electromagnetic Valve Actuation Motion Control on a Single Cylinder Engine," SAE Technical Paper 2013-01-0594, 2013, doi:10.4271/2013-01-0594.
In an effort to improve the efficiency of internal combustion engines, much focus has been put into variable valve actuation technologies in recent years. Electromagnetic solenoid valves can provide the cycle-by-cycle flexible valve timing needed for throttleless engine control or high efficiency combustion modes such as Homogeneous Charge Compression Ignition. One challenge with electromagnetic solenoid intake and exhaust valves is the robust control of the motion to achieve smooth landing under a variety of operating conditions. Promising algorithms have been demonstrated under test-bench conditions, but no work to date has demonstrated a robust electromagnetic valve-train on a functional engine that also satisfies soft landing and transition timing criteria. In this work, two previously developed valve motion controllers are experimentally tested on a single cylinder test engine. The controllers are compared for the opening transition of the exhaust valve with large variations in combustion pressure. A new control algorithm that combines favorable aspects of both methods is also presented. The new algorithm is shown to operate reliably under a wide range of operating conditions. An analysis indicates that the electrical energy consumed by the camless valve system is comparable to that of an equivalent conventional low friction cam-based valve train.