Variable timing camshaft drive system

US5606941A · kind A · utility

Assignee

• Dr. Ing. h.c. F. Porsche AG · DE

Inventors

• Alfred Trzmiel · Gräfenberg, DE
• Wolfgang Stephan · Heidelberg, DE
• Thomas Alber · Stuttgart, DE
• Andreas Jaksch · Eßlingen, DE
• Olaf Fiedler · Dresden, DE

Key dates

• Filing date: Aug 17, 1995
• Grant date: Mar 4, 1997
• Expiry date: Aug 17, 2015

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F01L1/348
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A variable valve timing camshaft drive system is provided with an adjusting device arranged between the loose end and the load end of a chain which is operative between chain wheels of two parallel camshafts of an internal-combustion engine. For tightening the chain and influencing the relative rotating position of a camshaft--variable valve timing--the device comprises a first hydraulic piston and a second hydraulic piston. The first hydraulic piston can be alternately acted upon by pressure and, in the process, takes up two end positions. By means of a third hydraulic piston, the first hydraulic piston may also be fixed in an intermediate position.