Daimlerchrysler Corporation

Chrysler Corporation

Michael J Reale

Kenneth P DeGroot

Bruce H Teague

Raymond J Sullivan

Dennis A Soltis

Mark J Duty

Timothy A Coatesworth

Yi Cheng

Thomas A Larson

Jonathan F Rose

Edward M Vuylsteke

A method of determining a goal voltage for a fuel/air sensor of an engine electronic fuel injection system includes the steps of determining a goal fuel/air sensor voltage, superimposing a wave form forcing function to the fuel/air sensor voltage for providing a goal fuel/air sensor voltage having a wave form pattern and controlling the engine to operate according to the goal fuel/air sensor voltage. The wave form forcing function provides the required fuel/air perturbations that are required to retain proper oxygen storage of the catalyst to maintain high three-way conversion efficiency.

Wave form fuel/air sensor target voltage

A method for reducing hydrocarbon emissions in an engine of a vehicle. The methodology is triggered following the switching off of the ignition by the operator. First, fuel delivery to the engine is terminated. Second, spark ignition is continued based on a predetermined parameter such as time or engine cycles following the termination of the fuel delivery. Last, spark ignition is stopped. Since combustion continues until no fuel exists in the cylinder, there is no over abundance of fuel in the catalyst at a subsequent start up. As such, the catalyst operates effectively at start up and hydrocarbon emissions are lowered.

Method for sparking engine cylinders after fuel shutdown for reduced emissions

An exhaust system is provided including two catalysts and three oxygen sensors. The second catalyst is disposed downstream of the first catalyst. The first oxygen sensor is disposed upstream of the first catalyst, the second oxygen sensor is disposed downstream of the first catalyst and upstream of the second catalyst, and the third oxygen sensor is disposed downstream of the second catalyst. A goal voltage corresponding to a desired level of oxygen within the exhaust is provided for the third oxygen sensor based on engine RPM and MAP. The engine controller compares the goal voltage to an actual voltage generated by the third oxygen sensor and an error value is obtained and converted into a goal voltage for the second oxygen sensor. The engine controller compares the goal voltage to an actual voltage generated by the second oxygen sensor and an error value is obtained and converted into a goal voltage for the first oxygen sensor. The engine controller compares the goal voltage to an actual voltage generated by the first oxygen sensor and an error value is obtained and converted into a percent-fuel correction by the engine controller.

Fuel control system with multiple oxygen sensors

An exhaust system is provided including two catalysts and three oxygen sensors. The second catalyst is disposed downstream of the first catalyst. The first oxygen sensor is disposed upstream of the first catalyst, the second oxygen sensor is disposed downstream of the first catalyst and upstream of the second catalyst, and the third oxygen sensor is disposed downstream of the second catalyst. A goal voltage corresponding to a desired level of nitrous oxide and hydrocarbon within the exhaust is provided for the third oxygen sensor. This goal voltage is based on engine RPM and MAP. The engine controller compares the goal voltage to an actual voltage generated by sensing the level of oxygen downstream of the second catalyst. Based on this comparison, an error value between the goal voltage and the actual voltage is obtained. This error value is converted into a goal voltage for the first oxygen sensor. An actual voltage generated by the first oxygen sensor sensing the amount of oxygen upstream of the first catalyst is compared to the goal voltage derived from the third oxygen sensor. The difference between the goal voltage and actual voltage is used to modulate the pulse width of a signal sent to the fuel injectors of an engine such that the amount of fuel delivered by the fuel injectors is modified. The second oxygen sensor generates an actual voltage corresponding to the amount of oxygen the second oxygen sensor senses downstream of the first catalyst and upstream of the second catalyst. Changes in the actual voltage generated by the second oxygen sensor are compared to changes in the actual voltage generated by the first oxygen sensor. By monitoring the nature of theses changes as they relate to one another, the performance of the first catalyst can be determined.

Triple oxygen sensor arrangement

A fuel control system is provided including a fuel tank, a purge vapor canister, a vapor line, and a fuel injector connected to an internal combustion engine. A purge vapor canister vent valve seals the purge vapor canister from the atmosphere such that the fuel tank, purge vapor canister, and fuel injector form a closed system. Upon initial starting of the engine, the purge vapor pressure is such that the purge vapor is drawn to the fuel injector from the dome portion of the fuel tank after passing through the purge vapor canister. Simultaneously therewith, the amount of liquid fuel is reducing or increasing by an amount of equally increasing or decreasing, respectively, vapor fuel so that a necessary mass flow rate is achieved to support combustion. As the amount of fuel vapors decreases to a negligible amount, combustion is supported by the atomization of liquid fuel. The delivery of the liquid fuel and vapor fuel is completed through the use of a fuel injector to accommodate both liquid and vapor form of fuel.

Purge assisted fuel injection

A method is provided for controlling spark advance based on a fuel modifier. Initially, engine fueling is reduced according to a known dynamic crankshaft fuel control (DCFC) methodology. As a result, the engine tends to run rougher. In response, spark advance is varied based on the overall fuel multiplier reduction from the DCFC methodology. For instance, a look-up table, or mathematical function based on the DCFC multiplier can be utilized as the basis for the spark advance.

Spark advance modifier based on a fuel modifier

A method is provided for enriching a fuel to air ratio in an engine during acceleration based on a known fuel multiplier. Initially, the method retrieves the fuel multiplier from a dynamic crankshaft fuel control (DCFC) system. This system uses the fuel multiplier to reduce the amount of fuel delivered to the engine. When acceleration is desired, the method increases the overall acceleration enrichment values as a function of the DCFC fuel multiplier. Thus, when the vehicle is launched via a throttle tip-in while the DCFC system is active, the acceleration enrichment values are increased thereby improving drivability by having combustion taking place in a richer environment.

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Royal Oak, MI, United States of America

Michael J Reale