Method and apparatus for testing internal combustion engines

US4809540A · kind A · utility

Assignee

• Avl Gesellschaft fur Verbrennungskraftmaschinen und Messtechnik m.b.H. Prof.Dr.Dr.h.c. Hans List · AT

Inventors

• Gerald Lackner · Arnoldstein, AT
• Heimo Denk · Feldbach, AT

Key dates

• Filing date: Nov 24, 1987
• Grant date: Mar 7, 1989
• Expiry date: Nov 24, 2007

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L23/085
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a method and apparatus for the evaluation of a starter motor current or of a magnitude proportional to it for determining the relative compressions of the cylinders of an internal combustion engine, in order to eliminate the distortion of the compression relationships between the individual cylinders, account is taken of the current/speed characteristic of the starter motor. Using a direct current series motor as the starter, from the starter current there is derived a magnitude N proportional to the actual speed according to the relationship N =1/i+k*i where i is the motor current. The correction factor K serves to take account of the departure of the characteristic from a hyperbolic curve.