James J. Gumbleton

Optimizing Engine Parameters with Exhaust Gas Recirculation

In addition to designing and developing hardware to control the exhaust gas recirculation (EGR) rate, it is equally important to tailor the other engine variables. Optimization of air-fuel ratio (A/F) and spark timing is required to achieve the best combination of oxides of nitrogen (NO sub x), hydrocarbon (HC), and carbon monoxide (CO) control, while minimizing the losses in fuel economy and drivability. This paper describes an engine dynamometer and vehicle study which defines the relationship between the above parameters.

ENERGY CONSERVATION WITH INCREASED COMPRESSION RATIO AND ELECTRONIC KNOCK CONTROL

This paper discusses the application of an electronic closed loop knock control system to a higher compression ratio engine to allow operation on 91 Research Octane Number fuel. Two cars with different compression ratios are compared with both oxidizing converter - EGR and 3-way oxidizing-reducing converter-EGR closed loop carburetor emission control systems.

EFFECT OF ENERGY AND EMISSION CONSTRAINTS ON COMPRESSION RATIO

This paper describes the results of a study to evaluate the relationship of compression ratio on fuel energy conservation with the constraint of the 1977 Federal emission standards (1.5 HC, 15.0 CO and 2.0 NOX). The influence of the energy losses in the refinery process to produce higher octane fuels was considered as well as the effect of compression ratio on engine efficiency. Two different emission control systems were evaluated: a catalytic converter-EGR system and a manifold reactor-EGR system. /GMRL/

EMISSION CONTROL WITH LEAN MIXTURES

Nitrogen oxide emissions can be controlled through engine operation with lean homogeneous air/fuel mixtures. This emission control approach precludes the need for exhaust gas recirculation (EGR) and secondary air injection systems. The Lean Mixture concept results in similar emissions, fuel economy, and driveability when compared to EGR systems tailored to similar emission levels with similar aftertreatment systems. A Lean Mixture-Manifold Reactor emission control system was used to evaluate the effect of compression ratio and leaded fuel on vehicle emissions and fuel economy. System durability is shown for a Lean Mixture-Catalytic Converter system with lead-free fuel and for a Lean Mixture system without aftertreatment with leaded fuel. /GMRL/

General Motors Progress Towards the Federal Research Objective Emission Levels

Six vehicles that have achieved the Federal research objective emission levels at low mileage are described. Two vehicles have completed 50,000 miles of durability below the .41/3.4/.41 g/mi levels. Two vehicles failed these emission levels by 10,000 miles. There is a loss in fuel economy of about 7% and the driveability range from non-commercial to beorderline commercial. The ongoing program objectives are to reduce the sensitivity of these systems to emission deterioration and driveability defects and to reduce the fuel economy losses.

Special Purpose Urban Cars

THREE SMALL, LIGHTWEIGHT URBAN CARS (THE 512 CAR SERIES) WERE TESTED BY GENERAL MOTORS. ONE BASIC BODY CONFIGURATION UTILIZED THREE DIFFERENT POWERPLANTS: A CONVENTIONAL GASOLINE ENGINE, A BATTERY-ELECTRIC, AND A HYBRID GASOLINE- ELECTRIC. THESE SMALL CARS WOULD HELP RELIEVE URBAN TRAFFIC AND PARKING PROBLEMS; THEIR LOW POWER REQUIREMENTS (TOP SPEED 30-45 MPH) RESULT IN LOW EXHAUST EMISSIONS. /HSL/