1991-01-01

The Variable Valve Timing System - Application on a V8 Engine 910009

Analyzed are the final test results obtained on the Ferrari V8 engine featuring engine heads having the Fiat variable valve timing system.Maintaining the base architecture of four camshafts overhead and four valves per cylinder, the VVT (regarding the intake and the exhaust) has provided record-level results at medium-to-low engine speeds, without penalizing the engine performance at high engine speeds.Improvements have also been made in fuel consumption as well as reducing the exhaust pollutants.Under analysis is the improved effect on both the “effective compression ratio” and the “expansion ratio” which together with the “volumetric efficiency” justify the high levels of the brake mean effective pressure (BMEP) obtained.Introduced here is the concept of the “sluggish area” of the standard sport engine performance, comparing the immediate response of the VVT to the partial loads at low-to-medium engine speeds.The final considerations on the racing engine applications complete this study.

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