Requirements for a Fully Variable Valvetrain and Realization with the Electro-Hydraulic Valvetrain System EHVS

Authors

K. Mischker, Robert Bosch GmbH, Stuttgart; D. Denger, AVL List GmbH, Graz

Year

2003

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 539

Summary

In order to achieve total control of engine combustion the three essential participants: charge exchange, mixture preparation and ignition are to be adjusted flexibly for every cylinder cycle by cycle. With two of them it has been reality for many years by means of the electronical ignition and injection, charge exchange is still mechanically coupled to the crankshaft. In the following the concept, the realization and first measurements of an full flexible electro-hydraulic system which controls charge exchange are described. Starting point is the question: What is actually necessary to achieve the potential and is it possible to mass-produce and to put the system on the market? A charge exchange control system, applicable to every type of engine (Otto, Diesel, heavy duty engines) and to every engine configuration (also with turbo charging and direct injection), which additionally enables alternativ combustion concepts (HCCI) is the objective. This system, the „Electro-Hydraulic Valvetrain System - EHVS“, consists of one hydraulic actuator for every engine valve, a hydraulic cycle including a high pressure pump as part of the engine oil cycle, and a control unit. First measurements show that a 4-cylinder engine supplied with EHVS, which is already designed to consider the possibilities of EHVS, offers compared with other new engines a high potential in fuel consumption, performance and emission.

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