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The critical challenge of improving fuel efficiency of new vehicles must be met if the world's finite petroleum supply is to be conserved for future generations. Automotive engineers will require new, more efficient design techniques to successfully meet the challenge. This paper presents the approach used in the design of GM's new 1978 intermediates as an example of how improved efficiency can be achieved. Factors affecting fuel consumption are outlined along with program goal setting. Areas of emphasis including weight reduction, powertrain optimization, and road load horsepower reductions are discussed as well as explanations of new engineering tools used.

THE SEARCH FOR improved packaging efficiency and flexible arrangements of available space has lead Renault to the use of front wheel drive. This paper outlines the development of four front wheel drive passenger cars at Renault and illustrates both similar and unique solutions adopted to achieve engineering and marketing objectives. To obtain truly optimized designs for different sizes and classes of vehicles, it is very difficult to use common body and chassis components on several distinct car lines.

This paper is an incremental report of an on-going program of the Automotive Engineering Department of the Automobile Club of Southern California in which desirable significant characteristics of today's automobiles are identified. Subjective and objective testing of current model year vehicles is conducted and the vehicles tested are ranked against a “target”. The results of the tests involving twenty-four vehicles are reported.

Evaluation techniques have been developed to insure that the new U. S. Marine Corps Landing Vehicle Assault (LVA)(1) will have an over-land performance at least equal to the Landing Vehicle, Tracked, Personnel, Model 7 (LVTP-7) which it will replace. Operations over roads, trails, cross-country, obstacles and across inland water barriers are considered for a specified mission scenario. The Cone Index and the Bekker Systems can be used independently or sequentially to represent soil strengths. A wide variety of performance data is available through an output processor. This ranges from over-all speed-made-good for the entire scenario to motion resistance, sprocket loadings, speed, fuel consumption, etc., for each scenario segment.

How and why Volvo arrived at the current Volvo-240 size is reported. Volvo's primary concern in the car-size debate has been related to the occupant, to his requirements for safe and comfortable transportation and to his human limitations. The basic philosophy of occupant packaging related to safety is given. Certain crashworthiness criteria in terms of vehicle deformation characteristics and Minimum Restraint Space are discussed. Comfort packaging criteria, particularly in view of seating and driver's work space are dealt with and so is the question of measuring seating comfort objectively. Summary findings from studies for confirming the validity of criteria presented are included.

Mechanical properties and welding characteristics of a commercial, dual-phase, low-carbon, cold-rolled steel are described. The new steel, HI-FORM 80d, exhibits a total elongation of about 24% as produced and develops a yield strength of about 625 MPa (91 ksi) in a formed and paint-baked part. Property uniformity is excellent and the weldability essentially equivalent to an AISI 1006 steel. In addition, the aging response of HI-FORM 80d is such that yield strengths near 550 MPa (80 ksi) can be achieved with strains of less than 2% and lower paint-bake temperatures than are currently in use.

The engineering objectives for the new Fairmont/Zephyr carlines include: Improve fuel economy by integrating aerodynamics into vehicle styling, reducing vehicle weight, and improving powertrain efficiencies, at no sacrifice of performance. Maximum package efficiency by providing maximum passenger roominess within the car's compact exterior. A comprehensive weight reduction program was initiated to improve fuel economy on the Fairmont/Zephyr carlines. New concepts in body and chassis design and selective usage of lightweight materials have resulted in a 245 lb. weight reduction versus 1977 Maverick. The car's structural strength, response, and durability has been verified by sophisticated computer techniques and extensive vehicle testing. It is believed that the Fairmont and Zephyr are the most significant cars to be introduced by Ford Motor Company in many years.

In November 1976, the Environmental Protection Agency promulgated rules covering the classification of automobiles for the purpose of fuel economy labeling and the Gas Mileage Guide. Since that time a number of changes have been made in the classification system and the interior volume measurements on which that system is based. This paper reports on the reasons for those changes and their impact on the classification of model year 1978 vehicles. The paper also discusses various trends in vehicle design as measured by interior and exterior volume, weight and fuel economy. Trends in varous design efficiency factors are examined for model years 1976-1978 and a data base is presented for future analysis.

This paper presents the results of tests of one-piece face bars. It develops tentative guidelines for assessing the resistance of aluminum bumpers to local damage. Resistance to denting is shown to depend on the magnitude and location of the load applied, and the yield strength and thickness of the material. Cracking resistance is dependent on load applied, configuration of the bumper, location of load, tensile strength and thickness of the material. Deformation capacity of the material also appears to be of importance.

Future automotive designs will increasingly require the substitution of reduced gage cold rolled high strength steel for the mild steel currently employed in order to meet vehicle weight reduction goals. The formability of HI-FORM 80d, a candidate cold rolled high strength steel was evaluated both by laboratory formability studies and by stamping trials of representative production parts. The parts chosen for the stamping trial were chosen to satisfy two criteria: that they were candidate parts for material substitution and that they encompassed the range of strain states found in automotive stampings. The results of this study indicate that, for its strength level, HI-FORM 80d exhibits good formability; the formability of HI-FORM 80d is similar to that of aluminum body panel material.

Automotive component weight can often be reduced by replacing plain carbon steel with thinner high strength steel. However, the poor formability of the latter steels has, in part, restricted their use. GM 980X has far better formability than conventional SAE 980X, high-strength low-alloy (HSLA) steels and can develop the strength of the SAE 980X steels in the formed part. This paper discusses the performance of GM 980X steel in various wheel rim and disc forming trials and in component fatigue tests conducted with the objective of meeting the established performance requirements of plain carbon steel wheels with lighter weight HSLA wheels. Results suggest that GM 980X can be a viable substitute for plain carbon steel in wheels with weight savings as high as 25%.

Intake and exhaust valve control has been combined with engine calibration control by an on-board computer to achieve a Variable Displacement Engine with improved BSFC during part throttle operation. The advent of the on-board computer, with its ability to provide integrated algorithms for the fast accurate flexible control of the entire powertrain, has allowed practical application of the valve disabler mechanism. The engine calibration basis and the displacement selection criteria are discussed, as are the fuel economy, emissions and behavior of a research vehicle on selected drive cycles ( Metro, Highway and Steady State ). Additionally, the impact upon vehicle driveability and other related subsystems ( e.g., transmission ) is addressed.

A mechanism has been developed which deactivates selected valves on a spark ignition engine. Greater fuel economy results from reduced throttling losses when using fewer cylinders under light load conditions. Several approaches were considered, with the releasable fulcrum proving to be the most effective concept. Subsequent engineering efforts refined the design to develop a simple bolt-on device which would meet specific performance requirements.

A comprehensive long-term test on bare, anodized, plated, and organic-coated aluminum bumper stock is underway at atmospheric test sites at Pompano Beach, Florida; Phoenix, Arizona; Richmond, Virginia; and Chicago, Illinois. Aluminum alloys exposed originally in 1975 included 7016, 7046, X7029, and two experimental compositions. New exposures in 1977 included alloys 7129, 7021, 6009 and 6010. Specimens are scheduled for removal after 1-, 2-, and 4-years - 2-year panels were retrieved and evaluated in 1977 from Florida and Phoenix. One-year results from Richmond and Chicago will be reported here. Fullsize aluminum bumpers (with and without rub strips) having organic coatings, anodized coatings, and chrome-plated finishes were exposed also, along with chrome-plated steel.

The authors developed a method to measure the air-fuel ratio at local points within the combustion chamber. The primary point is to obtain the pre-combustion air-fuel ratio of the mixture from the HC (vaporized fuel) and O2 concentrations. This procedure which consists of three parts, gas sampling, gas transport and gas analysis, renders it possible to perform direct quantitative HC analysis of samples. This method is carried out by either of two techniques: multi-cycle sampling (MCS) and single cycle sampling (SCS), and the average air-fuel ratio of many engine-cycles and the single engine-cycle were obtained respectively.

Bumper facebars formed from high strength aluminum sheet provide the design engineer with a cost effective way to achieve styling flexibility with substantial weight savings. Several prototype programs have defined candidate alloys, manufacturing sequences, and important part and tooling design guidelines for forming bumpers from aluminum sheet. The results of these programs are summarized. Four case histories are discussed.

Three-way catalysts provide a means of catalytically achieving lower NOx emission levels while maintaining good control of HC and CO emissions. However, very accurate control of air-fuel ratio is necessary. The precise air-fuel ratio control required is accomplished by employing a closed loop fuel metering system in conjunction with an exhaust gas sensor and an electronic control unit. To gain production experience with this type of system, General Motors is introducing it on two 1978 engine families sold in California. One is a 2.5 litre L-4 engine and the other is a 3.8 litre V-6 engine. Closed loop controlled carburetors are used on both systems. This paper discusses these 1978 systems. The components used on both systems are described and emission and fuel economy results are reviewed.

The objective of this paper is to describe the Ford Motor Company (Ford) approach of meeting exhaust emission regulations with a three-way catalyst and feedback control system. A pilot program was initiated to gain production experience with three-way catalyst systems in anticipation of expanded usage to meet future emission standards. The Ford system consists of a three-way catalyst with feedback control monitoring the exhaust oxygen concentration and controlling the fuel flow to produce a stoichiometric exhaust mixture. Mixture control is critical since catalyst NOx conversion efficiency is diminished when the exhaust mixture deviates from stoichiometry. Briefly, the control loop consists of zirconium dioxide exhaust sensor to indicate oxygen concentration, an electronic control unit, a vacuum regulator to proportion a vacuum signal to the carburetor, and a feedback controlled carburetor with vacuum modulated main fuel system.

This paper reports an effort to integrate into an engine/catalyst system the best available technologies in electronic engine controls, fuel systems, and catalysts for the purpose of developing a 4000 to 4500 lb vehicle that combines good fuel economy with the ability to meet the 0.41/3.4/0.40 gm/mi emission objectives for HC/CO/NOx. The system has been installed in a 1977 Ford Granada and tested under CVS-CH conditions with two different combinations of catalysts. The results of these experiments, along with analyses of the performance of major electronic and catalytic subsystems, are presented and discussed.

Measurements have been made of the emissions from a prototype three-way catalyst automobile, during normal and simulated malfunction driving conditions. Four ceramic-supported catalyst compositions were investigated, ranging from Rh through two mixtures of Rh-Pt to Pt. Driving conditions included cyclic and cruise modes. Under normal operating conditions no HCN was detected. Under rich malfunction conditions, HCN was generally observed, even in the absence of a catalyst. In some cases, catalysts appeared to remove HCN from the exhaust gas; in others they increased its level. The highest emission rate for HCN was observed for the Rh catalyst, about 40 mg/km at 64 kph cruise.