Daimlerchrysler Corporation

David P Ploucha

Roger C Sager

Gary D Dawson

Yi Cheng

Richard K Moote

Gary L Seitz

Howard W Krausman

Ronald A Reese, Ii

Ronald A Yannone, Jr

Zhong Li

Thomas W Stephens

Robert T Forgiel

Gary M Pallach

Susan A Aldridge

Craig Keighron

David A Barkman

Colleen M Donahue

A method of diagnosing an operating condition of a short runner valve in an intake manifold of an internal combustion engine using an exhaust sensor in an exhaust manifold of the internal combustion engine. The short runner valve is commanded to an open position for a test period, it is resolved whether the test period has elapsed, and it is determined whether a sensed exhaust gas parameter has exceeded a threshold during the test period. A pass signal is issued if the sensed exhaust gas parameter has exceeded the threshold within the test period. Otherwise, a fail signal is issued if the sensed exhaust gas parameter has not exceeded the threshold within the test period.

Short runner valve diagnostic

A method is provided for testing a thermostat in a motor vehicle. The method includes an engine warm-up model and a thermostat diagnostic. The engine warm-up model predicts the temperature that the engine coolant temperature should be equal to at a given time after start-up. This is based on the engine coolant temperature at start-up, ambient air temperature, and how the vehicle is driven subsequent to start-up. This predicted engine coolant temperature is compared to the actual engine coolant temperature as read by an engine coolant temperature sensor. The error between the predicted engine coolant temperature and the actual engine coolant temperature is calculated and integrated over time. The thermostat diagnostic runs at a pre-selected temperature after start-up and compares the integrated error to a predetermined threshold value. Depending upon the results of the comparison, a pass, fail, or inconclusive condition is determined.

Engine warm-up model and thermostat rationality diagnostic

A method of determining the quality of subsystems of an electronic engine control system is provided. The method monitors an engine parameter representative of a subsystem of interest and compares the parameter to at least one quality limit. The at least one quality limit represents an acceptable performance boundary for a fully functional engine control system. The method then indicates, based on the result of the comparison, whether the subsystem is of satisfactory quality. The method is arranged, without limitation, to determining the quality of start time, start flare, idle control during transmission shift, and speed control.

Verification engine controller software

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Ann Arbor, MI, United States of America

David P Ploucha