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A new analytical method, absorption of tunable diode laser radiation, can detect small concentrations of gases with fast response. This technique has been applied to the detection of vehicle sulfate emissions in the form of sulfuric acid (H2SO4) vapor. Previously available methods for sulfate analysis required collecting samples for 10 min. or more. Our laser system has a response time of 2.4 s. This allowed tracking the sulfate emissions of a vehicle during a Highway Fuel Economy Test. The data suggests that catalyst temperature is the major parameter controlling sulfate emissions and that storage and release of sulfur occurs at low and high catalyst temperatures, respectively. The same method detected methane during both the Highway Fuel Economy Test and the Federal Test Procedure. It identified the conditions, and corresponding concentrations, for high methane emissions. A qualitative comparison with total hydrocarbon emissions uncovered significant differences during accelerations.

The state of California has adopted a “real-time” evaporative emission procedure that will be used starting with the 1995 model year. This test, which focuses on high temperature conditions, and measures all sources of evaporative emissions, represents a very stringent requirement. Non-fuel background emissions, i.e., paint, adhesives, and even air conditioning refrigerant, can be a significant fraction of the total measured emissions. California has included a provision in their regulations that allows for the subtraction of background emissions, using a methodology to be developed in the future. This paper reviews the history of non-fuel emission regulations, provides data showing the magnitude of the problem using the new real-time procedure, and suggests a methodology for establishing a new background emission test procedure.

A new aluminum alloy bearing material containing lead-base babbitt is described. This material provides the performance advantages of an overplated babbitt construction without requiring the plating procedure. Performance characteristics including fatigue, wear, score, and corrosion resistances and embedability are compared to standard SAE bearing materials on the basis of laboratory tests. Extensive engine dynamometer and vehicle field tests are described to show the excellent durability of this new material.

The flow of oil into a rotating crankshaft has been investigated. Analysis of the physics of the problem together with dimensional analysis indicates, for a given journal geometry, that a relationship exists between Reynolds number, non-dimensionalized pressure drop, and oil flow. Data obtained from an oil flow test rig are used to determine explicit correlations for two oil feed configurations; one journal with and one journal without a lead-in groove.

To verify the relationship between bearing oil film thickness and high-temperature, high-shear (HTHS) engine oil viscosity, accurate values for bearing oil temperature and shear rate are needed. Techniques for making these determinations are presented using data collected from engine tests with both single- and multigrade oils. A regression model is developed for estimating bearing oil film temperature as a function of engine operating variables. Bearing oil temperatures can be more than 20°C greater than sump temperatures. The relationships between film thickness and viscosity evaluated at several bearing shear rates are described. If oil viscosity is evaluated at the maximum bearing shear rate, previously published findings which conclude that multigrade oils provide a thicker oil film than single-grade oils are verified.

Previous studies of human thoracic injury tolerance and mechanical response to blunt, midsternal, anteroposterior impact loading were reported by the authors at the 1970 SAE International Automobile Safety Conference and at the Fifteenth Stapp Car Crash Conference. The present paper documents additional studies from this continuing research program and provides an expansion and refinement of the data base established by the earlier work. Twenty-three additional unembalmed cadavers were tested using basically the same equipment and procedures reported previously, but for which new combinations of impactor mass and velocity were used in addition to supplementing other data already presented. Specifically, the 43 lb/11 mph (19.5 kg/4.9m/s) and 51 lb/16 mph (23.1 kg/7.2 m/s) conditions were intercrossed and data obtained at 43 lb/16 mph (19.5 kg/7.2 m/s) and 51 lb/11 mph (23.1 kg/4.9 m/s).

SAE 1046 steel axle I-beam forgings produced by the direct quench method and the conventional reheat and quench method were examined. Impact and tensile specimens obtained from sections of two direct quench and one conventional reheat and quench axle I-beams were tested. These data were correlated with hardness and microstructure to determine the relationship between microstructure and properties. The microstructure of direct quenched beams is coarse grained with a martensite case and bainite core. In contrast, the microstructure of conventionally heat treated beams is fine grained with a martensite and/or bainite case and pearlite core. Tensile and impact properties indicate that direct quenching is an acceptable alternative to the conventional reheat and quench process. Fatigue testing of direct quenched beams is currently being performed.

The General Motors Research Library online catalog provides electronic access to traditional library materials (books and journals), access to company documents (internal reports and product information), an alerting service, and links to non-bibliographic information. The Library also offers an online literature searching service as a supplement to the online catalog.

Oil film thickness measurements made in the front main bearing of an operating 3.8 L, V-6 engine were compared with rheological measurements made on a series of commercial and experimental oil blends. High-temperature, high-shear-rate viscosity measurements correlated with the film thicknesses of all single-grade and many multigrade oils. However, the film thicknesses provided by some multigrade oils were larger than could be accounted for by their high-temperature, high-shear-rate viscosities alone. Although the pressure-viscosity coefficients of some of the oils were significantly different from those of the majority of oils tested, they were not oils which produced unusual film thicknesses. As a consequence, correcting oil viscosities for the estimated pressures acting within the bearing was unsuccessful in improving the correlations. The correlations were improved, however, by accounting for the elastic properties of the multigrade oils.