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An electronic servo controller, combined with an electric chassis dynamometer and a synchronized mini-computer generated command signal, provides consistent and smooth driving of development vehicles on EPA emission runs. The electronic controller provides the necessary signals to actuate the throttle servo to power the engine, and to generate braking torque on the chassis rolls of the electric dynamometer. The servo gain and compensation circuits allow accurate and stable operation over a wide range of engine loads, transmission gear ratios, and car speeds. A single gain-compensation network is sufficient for vehicles used in AC's catalytic converter development program. Safety shutdown circuits and ease of installation are provided in the design.

A comprehensive EPA emission test analysis program has been developed to determine the nature and relative significance of test variability and to provide consistent evaluation of the performance of catalytic converters. This includes real-time recordings of emission concentrations and mass rates, catalytic converter efficiencies, and air-fuel ratio. Mass accumulations are printed out during the test at the end of each test mode. Test results and analysis of repeatability are summarized on-site immediately following the test. Simplified relationships between gas concentrations and engines variables have been developed.

A three-point program is described which provides overall control of vehicle emission testing and assurance of acceptable product design. 1. Experimental design techniques are used in the test development activities to control test parameters and to insure sufficient test repeatability for test evaluation. 2. Test histories, established and automatically maintained on computer files, are continuously monitored to assure test control and to provide insights into the effects of various test parameters. 3. The objectives of each specific test request are analyzed and experimental designs utilized to develop test plans and procedures. Illustrative examples in each area are included.

Piezoresistive phenomena found in silicon semiconductors and the possibility it has of integrating various electronic functions (all in one family of technology) are a viable method of meeting the future requirements of the automotive industry. After a brief discussion of the evolution of semiconductor sensors and the “state of art” design, the author proceeds to propose some suitable circuits for integration of electronic functions such as comparator, amplifier, A to D converter, etc. Although the discussion centers on pressure transducer design, the facts in the example can easily be transferred to temperature, flow, and acceleration measurements.

Hydraulic power braking systems for use in passenger cars and light trucks are attracting considerable automotive design attention. This is due to their compactness, smaller space requirements, and better operating “feel,” as well as their more direct control over the braking function, which has extremely short application and release times. Moreover, they are readily adaptable to the energy source and controls of an antilock system, and they contribute to (or even form the basis of) a central power-supply system that would provide servo assistance to other vehicle systems. This paper describes and explains ways of creating these brake systems and gives design calculations of brake layouts based on standard values and comparative judgment criteria.

Handicapped people can be taught to drive. This paper stresses the “family car” concept. If possible, the car should be adapted with special controls for the handicapped that do not preclude the car being driven by the able-bodied family members. Considerable attention is given to existing optional equipment that will assist the handicapped in performing the driving task. The ultimate goal for the handicapped is complete independence: enter the car, perform the driving task, and exit the car unassisted.

Unlike lithium chloride, chemical, and other surface-type elements, the Brady Array exhibits bulk effects conforming to the Poole-Frenkel law concerning bulk phenomena. Other types of sensors require agglomeration of water or moisture prior to measurement; in the array, measurements are accomplished at a discrete molecular level, resulting in extremely rapid response and recovery times (better than 150 ms). Stressed bonds within the structure initiate rapid recovery by purging the sensor when it is moved from higher to lower values of relative humidity. The sensing element is contained within a TO-5 type transistor housing, measuring only 10 mil in diameter and 100 mil in length. The array has been operated over temperature extremes ranging - 200 to +800°F without damage or loss of calibration. The technique employed in the array also lends itself to sensing of other gases, when constructed using techniques proprietary to Thunder Scientific Corp.

Research in the development of assistive devices (power brakes, power steering, automatic transmission, etc.) is geared to close the gap between the handicapped and the normal operator. This objective is accomplished by providing additional assistive devices that will not interfere with the normal operation of the vehicle, but will enable the disabled individual safely to operate the same vehicle. This is achieved by considering the anthropometric and biomechanical constraints of the impaired driver. The pistol-grip controller is discussed in detail. It is intended to control manipulation of the steering wheel, brakes, lights, horn, windshield wiper, windows, etc.

The use of relatively small catalytic converters containing alumina-supported platinum (Pt) and palladium (Pd) catalysts to control exhaust emissions of hydrocarbons (HC) and carbon monoxide (CO) was investigated in full-scale vehicle tests. Catalytic converters containing 70-80in3 of fresh catalyst were installed at two converter locations on the vehicle. Carburetion was richer than stoichiometric, with air-fuel ratios (A/F) comparable to those proposed for dual-catalyst systems containing an NOx reduction catalyst. The vehicle was equipped with exhaust manifold air injection. Homogeneous thermal reaction in the exhaust manifolds played a significant role in the overall control of HC and CO. Four Pt catalysts, three Pd catalysts, and one Pt-Pd catalyst were prepared and evaluated. Total metal loadings were varied 0.01-0.07 troy oz. Hydrocarbon conversion efficiencies varied 62-82%, measured over the 1975 cold-hot start weighted Federal Test Procedure.

Stringent emission standards have strongly affected the requirement for catalysts and catalytic converters. Since considerable emphasis is placed on cold-start performance, catalysts with lower density and higher oxidation activity at lower temperatures are required. Monolithic catalysts have been extensively evaluated in low-emission vehicles. This paper identifies the key phenomena associated with overtemperature and emission breakthrough problems in platinum monolithic converters.

The purpose of this paper is to elucidate and expand on the categorization of disabilities as they specifically relate to the driving task. The authors use the example of an amputee to derive the design parameters characteristic of a given disability. A lengthy table detailing the categories of amputation is included, and a discussion of the table in relation to driving an automobile is presented.

The particular difficulties encountered in designing fuel and ignition control in today's automobiles have led to consideration of electronic systems. These are totally dependent upon the transducers used to provide the information they require, and frequently the success of a given system depends upon the solution of some transducer problem. This paper discusses some of the alternative choices of input parameters to a control system intended to manage the fuel and ignition of an internal combustion engine. The requirements for, and designs for, transducers to measure throttle angle, crankshaft speed and position, air mass flow, engine component position, and exhaust quality are discussed.

An experimental study of a naturally aspirated, spark-ignited prechamber mounted in a CFR engine demonstrated that this system provides a marked improvement in lean-mixture combustion both before and after engine warm-up. In the system tested, a premixed fuel-air mixture containing five times the stoichiometric amount of fuel was supplied to the prechamber at a rate of 2% of the main chamber mixture flow. The fuel-rich flame issuing from the prechamber provided an ignition source capable of igniting main chamber mixtures much leaner than those normally ignitable by a standard spark plug. There are many advantages and disadvantages when comparing the standard CFR engine with the prechamber CFR engine. This paper goes on to explain the prechamber engine in detail and to compare it with the standard engine.

Most transducers offered commercially are suitable for laboratory, aerospace, or industrial process applications but do not meet additional, stringent automotive requirements. A need exists, both present and future, for various types of transducers in automotive powerplant control systems. Possible electronic systems and subsystems requiring transducers are discussed, and the types of transducers needed for these systems are described along with a discussion of a general set of specifications with respect to accuracy, reliability, and durability. Substantial transducer development is needed to enhance the advancement of certain automotive electronic systems. This paper points out these requirements to the electronics industry in an effort to encourage a mutual industry development that will advance the technology.

An investigation of the influence of surface roughness of lubricated rolling-sliding contact surfaces on pitting fatigue has been carried out. A significant increase in pitting resistance resulted from polishing the ground mating surfaces. When the roughness of the loading rollers (positive slip element) was reduced from 10-15 to 5-9 μin rms and that of the test specimen (negative slip element) from 10 to 2-3 μin rms, there was a gain of about 150% in load-carrying capacity before pitting occurred. The surface roughness of the loading roller appears to be the dominating factor. The degree of metallic contact and surface distress decreases when the roughness of the roller approaches the thickness of the oil film.

Some of the mobility problems faced by the spinal cord injury patient are presented in this paper. Existing automobile hand controls for the handicapped are discussed and current efforts at evaluation and standardization of this equipment are described. Design constraints are outlined for the development of new equipment to allow the more severely handicapped to drive.

A comprehensive scanning electron microscope(SEM) survey of the fracture surfaces of an aircraft main landing gear shock strut piston showed that improper shot peening contributed to the initiation of the anamolous fatigue failure. SEM photographs of the suspect-origin regions and the surrounding areas were analyzed. The photographs are presented, along with a detailed description of the regions observed. Failure mechanism is discussed, and causes of fracture origin explored.

An analysis of oil pumpability reveals that engine oil pumping failures may occur because either the oil cannot flow under its own head to the oil screen inlet, or the oil is too viscous to flow through the screen and inlet tube fast enough to satisfy pump demands. To determine which factor is controlling, the behavior of commercial, multigraded oils was observed visually at temperatures from -40 to 0°F (-40 to - 17.8°C) in a laboratory oil pumpability test apparatus. Test results revealed that pumping failures occur by the first alternative: a hole is formed in the oil, and the surrounding oil is unable to flow into the hole fast enough to satisfy the pump. Of 14 oils tested, 7 failed to be pumped because of air binding or cavitation which developed in this manner. A model, which explains these failures in terms of yield point considerations and the low shear apparent viscosity of the oils, is proposed.

The inability of certain crankcase oils to flow and lubricate an engine at low temperature and the lack of a suitable bench test to predict this characteristic are of current concern to engine builders and oil formulators. Two critical areas of oil flow at very low temperatures have been recognized by SAE and ASTM subcommittees. These are: the ability of an oil to flow to the oil screen of an engine fast enough to prevent “air binding,” and its ability to be drawn through the oil screen and pump inlet tubing without causing “pump cavitation.” The interrelation between these two factors is discussed and some engine pumpability data are presented which illustrate how one of these factors may affect the other. Descriptions of four new bench tests are presented along with data to show their ability to predict the low-temperature pumpability properties of crankcase oils.

This paper describes a diffused semiconductor strain gage pressure transducer designed for use as a manifold vacuum sensor in electronic ignition and electronic fuel injection systems. The design philosophy, construction, and the calibration techniques used to enable the subject transducer to perform accurately over a broad range of environments and maintain this performance for thousands of miles without periodic recalibration, are discussed.