Patent ID: 7353795
Filing Date: 2008-04-08
Classification: F02D,G01M

Abstract:
1. A method of diagnosing an engine cylinder in a multi-cylinder piston engine the method comprising; operating the engine at a controlled load and controlled fuel consumption; measuring the power output or fuel consumption of a first cylinder undergoing two power strokes; shutting off fuel to a misperforming sequential cylinder in the firing order of the engine; running the misperforming sequential cylinder through a compression stroke during one of said power strokes of the first cylinder with no engine brake applied to the misperforming sequential cylinder; running the misperforming sequential cylinder through a compression stroke during another of said power strokes of the first cylinder with an engine brake applied to the sequential cylinder to open the exhaust valve of the sequential cylinder near the end of the compression stroke to release any pressure buildup; and comparing the power output or fuel consumption during the two power strokes to determine if there was a difference greater than a predetermined amount either in the power output or fuel consumption for diagnosing if the misperforming sequential cylinder has a faulty compression due to a difference less than the predetermined amount or faulty fuel delivery due to a difference greater than the predetermined amount.