Gm Global Technolgoy Operations, Inc.

Gregory E Labus

Sam Raghuma Reddy

Kurt D Mc Lain

Gary Arthur Nichols

William R Cadman

Gregory E Rich

Chad W Lehner

Jerry William Kortge

Joseph M Kotzan

Timothy E Mc Carthy

Myron Harold Bell

Michael P De Ronne

Marc J Gonsiorowski

Stephen D Matteson

Franz A Lieder

A fuel control system that regulates a purge flow from a fueling system to an engine includes a sensor that monitors an engine speed and a first module that determines a PWM frequency of a purge valve based on the engine speed. The PWM frequency includes a first period that is based on a second period that corresponds to two engine cycles. A second module regulates the purge valve based on the PWM frequency during engine operation.

Purge flow control to reduce air/fuel ratio imbalance

A leak detection system for a vehicle includes a fuel system and a controller. The controller communicates with the fuel system to detect a fuel filling event. The controller initiates a vapor leak test of the fuel system and terminates the vapor leak test if a fuel filling event is detected.

Fuel filling detection

A fuel system with a pressure-sensitive monitor accumulates multiple pressure-related sample points and estimates the general trend of pressure change in a fuel system over time, thereby detecting the presence or absence of a fuel vapor leak in the fuel system.

Apparatus and method for fuel vapor leak detection

The engine or powertrain control module of a vehicle remains electrically powered after the engine is stopped and is used to assess whether there is a leak in the evaporative emissions control system. Fuel tank temperature and pressure data, as well as fuel level data, is analyzed over a brief period of time by module and, if ambient conditions are suitable, the vent on the fuel adsorption canister is closed by signal from the module. The system is thus sealed and the module then analyzes the system pressure changes over a second brief period as the fuel cools by heat loss to detect the vacuum that will occur if the system has no leak.

Leak detection for a vapor handling system

An idle air control system diagnostic for an internal combustion engine which utilizes RPM, engine timing and intake airflow measurements to detect the presence of idle RPM faults and eliminate or verify the idle air control system as the fault source. Engine idle RPM is measured and compared with a commanded idle RPM, and if within a predetermined range, an idle RPM fault exists and one of two additional tests (non-intrusive and intrusive) is conducted to determine whether the idle air control system is the source of the fault. In the non-intrusive test, intake airflow is measured and compared to a predetermined intake airflow value, and if not within a predetermined range, the idle air control system is determined to be the fault source. In the intrusive test, variations in intake airflow (or intake manifold pressure) are measured in response to variations in the movement of the engine throttle-bypass airway pintle. If no intake airflow variations are detected, the idle air control system is determined to be the fault source.

Idle air control system diagnostic

A comprehensive air injection system diagnostic uses hardware already available on many vehicle exhaust systems to monitor the oxygen content of the exhaust, so as to indicate steady state oxygen levels therein that are not in accord with the present state of the air injection system, and accordingly are assumed to be the result of a failure in the air injection system.

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Fenton, MI, United States of America

Gregory E Labus