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Since the pneumatic farm tire was developed, the basic carcass construction has been bias or diagonal plies. As tractor manufacturers continue to produce models with higher and higher horsepower, it has become evident that the conventional design changes--lug shape, lug angle, aspect ratio, etc.--are no longer sufficient to achieve significant improvements in tractor drive wheel tire performance. After investigating various alternatives, B.F.Goodrich determined that a radial construction offered distinct performance advantages over a bias construction without requiring any redesigning of the tractor. These include: increased traction, reduced fuel consumption, longer wear and improved ride. This paper will present comparative performance results of radial and bias drive wheel tractor tires, and discuss the basic radial tire mechanics which make the performance improvements possible.

Chrysler Corporation used a mini-systems approach in the design and manufacture of a new generation of small cars, not merely new models. These cars are the Plymouth Volare and Dodge Aspen. A new generation of cars is defined as a full line of vehicles - 2-door coupe, 4-door sedan, and 4-door station wagon - which offer customers new values for this size car, especially in the areas of rideability, handling, fuel efficiency, visibility, roominess, comfort, quietness and amenities. In addition, a new generation of cars means an adaptable and cost-efficient product that, because of its design and manufacturing flexibility, can serve as a model for the resizing and redesign of the corporation's complete line of cars in the last half of this decade.

The emission control of small naturally aspirated diesels has posed severe problems and it has been generally thought that their acceptability in pollution sensitive areas would decline. The investigation described attempts to reverse this view. The exhaust quality of engines of this type can be improved by reducing the combustion temperatures and/or reducing the initial heat release rate: a range of methods of achieving this were examined and found commercially unacceptable. A qualitative review of the problem led to the evolution of a modified cycle characterized by high turbulence leading to higher air/fuel mixing rates and faster diffusion burning. This “Squish Lip” combustion system allowed CARB 1977 projected emission levels to be met on development engines without performance deterioration. Bench and field trials are in hand and a second generation system for truck applications is being evaluated.

Experimental insight derived from the measurement of heat transfer rates is useful in a number of engine-related activities-ranging from developing simulations for predicting engine performance to defining cooling requirements for insuring the integrity of engine materials. Consequently, a device for measuring steady-state heat-transfer rates in a solid was designed after an extensive heat-transfer analysis. Subsequent experimentation and development has led to an accurate miniature sensor which can be installed directly into a parent material with little thermal disturbance. An analytical model of the sensor, installed in the combustion chamber wall of an engine, predicted this disturbance error to be 3% or less over a wide range of parent material properties and engine operating conditions. Experimentation at four heat-transfer rates confirmed this predicted performance.

Three different types of temperature measurement on the automobile and the development of suitable controls are discussed. High temperature probe controls for emission catalysts; small, fast response thermostats for engine blocks; and PTC ceramic sensors for a variety of uses are developed.

Crushed samples of Engelhard PTX (II-B) catalyst were calcined at temperatures between 900-2700°F. When the temperature exceeds about 1100°F in air, the crystallites of precious metals (platinum-palladium) grow larger, exposing less surface for catalysis. When the catalyst is exposed to temperatures on the order of 1500-1800°F for extended periods of time (16 h or more), the wash-coat tends to lose a substantial percentage of its surface area. Finally, above about 2300°F, the cordierite of the ceramic becomes converted to mullite and amorphous material. The intrinsic rate constant for the oxidation of pure propylene is inversely related to Pt-Pd crystallite size. Thus, in the absence of poisoning, changes in intrinsic oxidation rate constant can be accounted for by changes in degree of dispersion of precious metal.

Experimental results with a 25-hp charge-cooled rotary combustion engine are presented for a variety of lubricant base stocks and additive packages. A rating method which combines endurance and deposition level is described. Lubricant performance is evaluated based upon this rating scheme, and contribution of base stock and additive package components is analyzed.

The mechanism of reduction of nitric oxide by hydrogen and carbon monoxide was studied on base metal catalysts under simulated automobile exhaust conditions. The catalysts were low copper-nickel alloys supported on an all-metal open-mesh substrate. Space velocity and concentrations of inlet and outlet NO, H2, CO, and O2 were used as study parameters. Dependence of ammonia formation on the hydrogen content in the gas was established. It was found that the dependence of ammonia formation on the oxygen content could be accounted for by the reaction of oxygen with the hydrogen produced by the water-gas reaction. In general, indications were obtained that under the conditions studied, the reduction of NO on base metal catalysts proceeds by a mechanism in which ammonia is an intermediate.

Platinum resistance sensors are currently used for continuous service from -260°C to +800°C and up to 1200°C for short term use. The historical development of resistance sensors is discussed and the advantages of using platinum resistance sensors over thermocouples is described. Parameters used in the evaluation of platinum sensors and signal conditioners are enumerated. Errors encountered in temperature measuring schemes and methods to reduce these errors are summarized.

A monolithic integrated circuit has been developed that is a sensor, a voltage reference, and an operational amplifier, all in a simple four-lead package. Although the circuit is designed to sense absolute temperature as a physical parameter, certain application techniques allow other inputs to be handled. Differential temperature, position, and air velocity can be converted to analog, on-off, or frequency outputs as desired. Specific examples are provided.

A radiometric method has been developed to measure apex seal wear in rotary engines. Seal wear rates are measured in ranges of μg/min without engine disassembly, and at various speed and load conditions using a dynamometer. The method incorporates radioactive apex seals in the front rotor of a Mazda 10A engine. Neutron irradiation of commercial carbon-aluminum apex seals produced radioisotopes of iron and chromium. Experimental carbon-aluminum seals, containing terbium oxide as an additive to improve the nuclear properties of the seals, were also used. The radiometric method involves the following steps: 1.operation of a rotary engine at any desired engine condition with radioactive apex seals, 2.collection of the seal wear debris by filtering the exhaust gas, and 3.the quantitative determination of the resulting radioactivity on the filter medium.

The deactivation of noble metal oxidation catalysts by lead and halide lead scavengers was studied in engine and laboratory experiments. The halide scavengers caused rapid but completely reversible inhibition of the catalyst activity, which existed only as long as the halide was present. The effects of catalyst temperature and noble metal concentration indicated that the halide scavenger dissociated upon adsorption on the catalyst. Palladium and platinum-palladium catalysts were more susceptible to halide inhibition than were platinum catalysts. Lead alone or lead plus scavengers produced a persistent poisoning of the catalyst. Lead poisoning effects were increased by increased catalyst temperatures and fuel lead content. Tests with scavengers only, conducted in an engine previously operated on leaded fuel, showed that lead was transported to the catalyst causing lead poisoning even in the absence of lead in the fuel.

Rear disc brakes were released as standard equipment on 1975 Mark IV and as a regular production option on 1975 Lincoln, Thunderbird, and Mercury. This brake is the result of a joint Ford/Kelsey-Hayes design and development effort. The key feature is a single-piston sliding caliper with an integral, self-adjusting parking brake mechanism. The design offers great flexibility in packaging on various car lines and on different axles. This paper describes the major features of the design and the significant problems found and overcome in the development program.

As a major contribution to the active safety of a vehicle, disc brakes have been available for over 20 years. However, recent efforts to improve directional stability when braking, and the implications of the various European and American legal requirements, particularly their influence on brake system design and performance, gives cause for a general review of the disc brake, how it has been used in the past, and what the future will mean. It is concluded that while some vehicle manufacturers are showing the way to improved braking performance, it will be desirable for others to follow suit to meet the challenges facing the automotive industry of the next decade.

Ageing tests were conducted on two monolithic noble-metal oxidation catalysts on an engine using various fuels and oils, and in a furnace with an air atmosphere. The activity of the aged catalysts was determined by laboratory apparatus and related to the results of chemical analyses of the catalyst specimens. It was found that pure thermal ageing at temperatures above 700° C can lead to a severe loss of activity even without additional catalyst poisoning. Of the impurities contained in the fuel, phosphorus is the most dangerous catalyst poison. Changing from a lead and phosphorus sterile fuel to a ‘lead-free’ fuel in accordance with the EPA specification leads to a noticeable worsening of ageing results. Within the anticipated range of sulfur concentration, sulfur has no influence on long-term results. The choice of engine oil affects catalyst ageing only slightly.

Some equations have been statistically obtained for calculating the combustion properties of gasolines from simple analytical data like density and FIA analysis (hydrocarbon composition: saturates, olefins, aromatics) or PONA analysis (hydrocarbon composition: paraffins, olefins, naphthenes, aromatics). The equations have been obtained by applying multiple correlation analysis to data calculated for 66 commercial and 58 experimental gasolines knowing their GC composition and the properties of each hydrocarbon which were obtained from the literature. The heat of combustion, and the Carbon to Hydrogen (C/H) ratio calculated by means of these equations have been experimentally verified by means of normal analytical methods. Good agreement has been found for both these quantities and for the other combustion characteristics such as, air to fuel ratio (A/F), water of combustion, and molecular expansion, all of which are directly related to the above.

This paper evaluates the performance of monolithic automotive exhaust catalysts under conditions of actual customer usage. Conclusions are based upon a field test that involved 450 catalyst equipped cars which accumulated 7.3 million miles of customer driving by the end of July, 1974. Based upon the results obtained from the 450 catalyst equipped vehicles, it was concluded that the monolithic type catalyst is an efficient device for reducing hydrocarbon and carbon monoxide emissions in customer usage. The effects of accumulated vehicle mileage, engine maintenance, three alternate catalyst designs, catalyst overtemperature, partially melted catalysts, misfueling with leaded fuel, and vehicular accidents on the performance of the catalyst system are discussed.

Cold weather tests have been conducted on various engine components to monitor their operational modes at differing ambient temperatures. The results presented in this paper provide insight into the influence these components have on characteristic exhaust emissions at low ambient temperatures. In addition, atmospheric pollution levels have been monitored in general across Canada and specifically by the City of Toronto, Ontario, which indicate that seasonally these levels do not increase in cold weather. This is contradictory to the motor vehicle emission performance. Reasons for this apparent contradiction are expressed in this paper.

Because of the minute quantity of sulfur in gasoline, all gasoline-powered vehicles emit sulfur oxides. Automotive emissions of sulfur oxides, however, are insignificant since, according to a 1970 Environmental Protection Agency estimate, gasoline-powered vehicles are responsible for only 0.6% of sulfur oxide emissions nationwide. Furthermore, all of the sulfur oxides in the atmosphere are gradually oxidized to sulfuric acid and sulfate by natural processes. Catalytic converters of the type installed on 1975 model automobiles reduce hydrocarbon and carbon monoxide emissions by oxidizing them to carbon dioxide and water. In the process some of the sulfur dioxide in the exhaust gas is also oxidized to sulfur trioxide, which combines with water to form sulfuric acid and sulfates. Sulfate emissions from 19 catalyst cars, 4 noncatalyst cars, and one diesel passenger car were measured with the 1972 Federal Test Procedure (FTP).

Low nitric oxide (NO) emissions and good fuel economy are obtainable at very lean mixtures. However, unstable operation caused by misfire and erratic combustion prevents present spark ignition engines from being operated very lean. A study was undertaken to understand what causes very lean mixtures to misfire in engines. The effects of mixture preparation, intake airflow, exhaust gas recirculation (simulated by N2 dilution), compression ratio, intake mixture temperature, engine speed, number of spark plugs and spark plug locations were investigated at minimum advance for best torque (MBT) spark timing in single-cylinder engines. Propane and isooctane were the fuels used. Results showed that leaner operation was possible with improved mixture preparation, increased airflow, decreased nitrogen (N2) dilution, increased compression ratio, increased mixture temperature, decreased engine speed, more central spark location, and multiple spark plugs.