The Effect of Increased Exhaust Gas Recirculation on Gasoline Direct-Injection Engine Performance, 03-R9596

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Principal Investigator
Terrence Alger

Inclusive Dates:  01/01/06 – 10/30/06

Background - This work is an outgrowth of two previous internal research projects for advanced combustion engines. The first project, quick-look internal research project 03-R9295, proved the hypothesis that the carefully combined use of high-energy ignition, Exhaust Gas Recirculation (EGR), and intake-air boost would result in very low emissions accompanied by high engine efficiency. The second project, internal research project 03-R9386, continued efforts from the first program, utilizing a medium-duty, multicylinder engine. The results of these programs and the data coming from SwRI's HEDGE® consortium have shown that there is considerable advantage to running an engine with high EGR and a high-energy ignition system. This project plans to investigate the potential synergies between gasoline direct injection (GDI) and high EGR operation.

Approach - The goal is to show the fuel economy and performance benefit of high EGR operation to a boosted, downsized GDI engine. A major engine manufacturer supplied a 1.6-liter, in-line four-cylinder engine for use on this project. An SwRI Rapid Prototyping Electronic Control System (RPECS) will be used to control engine function. The program is concentrating on developing the synergies between GDI operation and high EGR operation, with a focus on using an advanced ignition system and the GDI capabilities to improve the EGR tolerance and knock resistance in the engine. The program will be using knowledge developed under a previous IR program (03-R9525) to improve the ignition system of the engine to promote higher EGR tolerance and improve the burn rates. The addition of EGR will help improve fuel economy and emissions by flame temperatures. The reduction in flame temperatures will result in lower NO emissions and an improvement in the engine's knock tolerance, as well as lower exhaust temperatures. A reduction in knock tendency coupled with lower exhaust temperatures can lead to improved emissions at high load, where gasoline engines are traditionally weak.

Accomplishments - The engine has been acquired and instrumented and is currently being run-in to stabilize engine friction. The ignition systems, RPECS controller, and EGR systems are being fabricated. SwRI is working closely with our original equipment manufacturer partner to plan and execute the testing for maximum results.

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