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Initial Test Results of an Electro-Hydraulic variable-Valve Actuation System on a Firing Engine
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Abstract
An electro-hydraulic variable valve actuation (henceforth, referred to as WA) system has been developed for spark ignition engine applications. This is a report of its successful initial testing.
Motoring tests were first conducted to determine any cylinder to cylinder variations in charging efficiencies. These were then corrected by individual intake valve timings.
Then testing was conducted on a firing engine at both part and full load over a full range of engine speeds. The brake specific fuel consumption (bsfc) was considerably improved at low speeds by the WA system. However, the bsfc results of the WA system were worse than those of the throttled engine system at higher speeds and low loads. The cause of this problem was determined to be poor mixture preparation and various corrective measures are now being studied.
The WA system was very effective at full load over the entire speed range and increased output torque by more than 10% at the lower engine speeds compared to the production engine.
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Citation
Lenz, H., Geringer, B., Smetana, G., and Dachs, A., "Initial Test Results of an Electro-Hydraulic variable-Valve Actuation System on a Firing Engine," SAE Technical Paper 890678, 1989, https://doi.org/10.4271/890678.Also In
References
- Tuttle James Controlling Engine Load by Means of Late Intake Valve closing. SAE Paper 800794 1980
- Tuttle James Engine Load Controlled via Early Intake Valve Closing. SAE Paper 820408 1982
- Ma Tom Effect of Variable Engine Valve Timing on Fuel Economy. SAE Paper 880390 1988
- Gray C A Review of Variable Engine Valve Timing. SAE Paper 880386 1988
- Geringer Bernhard Theoretische und praktsiche Entwickiung einer variablen Ventilsteuerung auf elektronisch-hydraulischer Basis. VDI-Fortschritt-bericht Nr. 95 1988 Reihe 12
- Wichart Klaus Mőglichkeiten and Maβnahmen zur Verminderung der Ladungswechseiverluste beim Ottomotor. VDI-Fortschrittbericht Nr. 91 1987 Reihe 12
- Geringer Bernhard Berechnung und Entwickiung einer elektronisch-hydraulisch gesteuerten variablen Ventilsteuerung für Ottomotoren. VDI-Fortschritt-bericht Nr. 74 1986 Reihe 12, S.220/243