Refine Your Search



Search Results

Technical Paper

Adaptation of a Variable Displacement Vane Pump to Engine Lube Oil Applications

Variable valve actuation has become a very popular feature in today's engines. With many of these systems being hydraulically actuated, the engine lubrication system requires enhancement to support their function. To expand the system's operational range with respect to speed and temperature, a traditional solution has been to increase oil pressure by increasing pump displacement. To better optimize the system, a variable displacement vane pump has been adapted to the engine lube oil system. Based on existing transmission pump technology, a pivoting cam ring design is employed that is able to vary the pump's displacement as a function of pump regulating oil pressure which in-turn provides a net reduction in its drive torque. While others have addressed this issue using complex and expensive pressure regulating systems, this passive solution requires no valves or additional hardware.
Technical Paper

Piston Fuel Film Observations in an Optical Access GDI Engine

A gasoline direct injection fuel spray was observed using a fired, optical access, square cross-section single cylinder research engine and high-speed video imaging. Spray interaction with the piston is described qualitatively, and the results are compared with Computational Fluid Dynamics (CFD) simulation results using KIVA-3V version 2. CFD simulations predicted that within the operating window for stratified charge operation, between 1% and 4% of the injected fuel would remain on the piston as a liquid film, dependent primarily on piston temperature. The experimental results support the CFD simulations qualitatively, but the amount of fuel film remaining on the piston appears to be under-predicted. High-speed video footage shows a vigorous spray impingement on the piston crown, resulting in vapor production.
Technical Paper

Adaptive Hydraulic Braking Traction Control for the 2003 Chevrolet Kodiak and GMC TopKick

The development and application of a traction control Kodiak and GMC TopKick are explained. Most traction systems use engine management to enable traction control, while the adaptive braking system can provide traction assist for either gas or Diesel powered vehicles from 14,000 lbs. to 33,000 lbs. GVW. The performance driven criteria that established the design requirements and the development of a new product to meet these objectives are discussed. Both the vehicle manufacturer and the traction controller supplier provided these criteria. The basic ABS and traction control hydraulic schematics will be described as they apply to the vehicles. The results of the development program will be compared to the criteria used to establish the goals, and the benefits of the traction control system will be discussed.
Technical Paper

Technical Potential for Thermally Driven Mobile A/C Systems

Aqua-ammonia absorption refrigeration cycle and R-134a Vapor jet-ejector refrigeration cycle for automotive air-conditioning were studied and analyzed. Thermally activated refrigeration cycles would utilize combustion engine exhaust gas or engine coolant to supply heat to the generator. For the absorption system, the thermodynamic cycle was analyzed and pressures, temperatures, concentrations, enthalpies, and mass flow rates at every point were computed based on input parameters simulate practical operating conditions of vehicles. Then, heat addition to the generator, heat removal rates from absorber, condenser, and rectifying unit, and total rejection heat transfer area were all calculated. For the jet-ejector system, the optimum ejector vapor mass ratio based on similar input parameters was found by solving diffuser's conservation equations of continuity, momentum, energy, and flow through primary ejector nozzle simultaneously.
Technical Paper

Low-Power Flexible Controls Architecture for General Motors Partnership for a New Generation (Pngv) Precept Vehicle

The complexity of designing and implementing a vehicle electrical control system for ultra fuel-efficient hybrid vehicles is significantly greater than that of a conventional vehicle. To quickly demonstrate and iterate capabilities of these vehicles, an efficient and rapid means for developing requirements, mapping these into an electrical control and communications architecture, and developing prototype systems is needed. The General Motors Precept concept vehicle is an example of an energy- efficient vehicular control system developed using a "requirements to software'' development process and electronic controller infrastructure that demonstrates these attributes. The Precept is General Motors Corporation's technology demonstration concept vehicle developed to address General Motors Corporation's commitment to the Partnership for a New Generation (PNGV) program.
Technical Paper

Automotive A/C System Integrated with Electrically-Controlled Variable Capacity Scroll Compressor and Fuzzy Logic Refrigerant Flow Management

This paper describes the recent efforts on developing an automotive climate control system throughout integrating an electrically-controlled variable capacity scroll compressor with a fuzzy logic control-based refrigerant flow management. Applying electrically-controlled variable capacity compressor technology to climate control systems has a significant impact on improving vehicle fuel economy, achieving higher passenger comfort level, and extending air and refrigerant temperature controllability as well. In this regard, it is very important for automotive climate control engineers to layout a system-level temperature control strategy so that the operation of variable capacity compressor can be optimized through integrating the component control schemes into the system-level temperature control. Electronically controlled expansion devices have become widely available in automotive air conditioning (A/C) systems for the future vehicle applications(1, 2, 3 and 4).
Technical Paper

Chemiluminescence Measurements of Homogeneous Charge Compression Ignition (HCCI) Combustion

A spectroscopic diagnostic system was designed to study the effects of different engine parameters on the chemiluminescence characteristic of HCCI combustion. The engine parameters studied in this work were intake temperature, fuel delivery method, fueling rate (load), air-fuel ratio, and the effect of partial fuel reforming due to intake charge preheating. At each data point, a set of time-resolved spectra were obtained along with the cylinder pressure and exhaust emissions data. It was determined that different engine parameters affect the ignition timing of HCCI combustion without altering the reaction pathways of the fuel after the combustion has started. The chemiluminescence spectra of HCCI combustion appear as several distinct peaks corresponding to emission from CHO, HCHO, CH, and OH superimposed on top of a CO-O continuum. A strong correlation was found between the chemiluminescence light intensity and the rate of heat release.
Technical Paper

General Motors DEXRON®-VI Global Service-Fill Specification

During early 2005 General Motors released a newly developed ATF for the factory fill of all GM Powertrain stepped gear automatic transmissions. The new fluid provided significantly improved performance in terms of friction durability, viscosity stability, aeration and foam control and oxidation resistance. In addition, the fluid has the potential to enable improved fuel economy and extended drain intervals. Since the performance of the new fluid far exceeded that of the DEXRON®-III service fill fluids available at the time it became necessary to upgrade the DEXRON® service fill specification in order to ensure that similar fluids were available in the market for service and repair situations. This latest upgrade to the service fill specification is designated DEXRON®-VI [1].
Technical Paper

Emissions of Toxicologically Relevant Compounds Using Dibutyl Maleate and Tripropylene Glycol Monomethyl Ether Diesel Fuel Additives to Lower NOx Emissions

A previous paper reported (SAE Paper 2002-01-2884) that it was possible to decrease mode-weighted NOx emissions compared to the OEM calibration with corresponding increases in particulate matter (PM) emissions. These PM emission increases were partially overcome with the use of oxygenated diesel fuel additives. We wanted to know if compounds of toxicological concern were emitted more or less using oxygenated diesel fuel additives that were used in conjunction with a modified engine operating strategy to lower engine-out NOx emissions. Emissions of toxicologically relevant compounds from fuels containing triproplyene glycol monomethyl ether and dibutyl maleate were the same or lower compared to a low sulfur fuel (15 ppm sulfur) even under engine operating conditions designed to lower engine-out NOx emissions.
Technical Paper

Developing Hydrogen (H2) Specification Guidelines for Proton Exchange Membrane (PEM) Fuel Cell Vehicles

In 1999, the Society of Automotive Engineers established the Fuel Cell Standards Committee (FCSC). The Committee is organized in subcommittees that address issues such as Interface, Hydrogen (H2) Quality, Safety, Performance, Emissions and Fuel Consumption, Recycling and Terminology. Since its inception the SAE/FCSC has published several recommended practices, which have drawn the attention of national and international organizations. These include SAE J2578 (Fuel Cell Vehicle Safety), SAE J2600 (Compressed H2 Surface Vehicle Refueling Devices), and SAE J2594 (Recyclability of Fuel Cell Systems). The need for having one common grade of hydrogen for all US commercial hydrogen-refueling stations for FCVs was the reason to establish the H2 Quality Task Force (HQTF) in late 2003. At the present time there is no representative US-national or international standard addressing the quality of hydrogen fuel that is acceptable for fuel cell vehicles.
Technical Paper

Evaluation of a High Speed, High Resolution Gas Chromatography Instrument for Exhaust Hydrocarbon Speciation

The ozone forming potential (OFP) and specific reactivity (SR) of tailpipe exhaust are among the factors that determine the environmental impact of a motor vehicle. OFP and SR measurements require a lengthy determination of about 190 non-methane hydrocarbon species. A rapid gas chromatography (GC) instrument has been constructed to separate both the light (C2 - C4) and the midrange (C5 - C12) hydrocarbons in less than 10 minutes. The limit of detection is about 0.002 parts per million carbon (ppmC). Thirty exhaust samples from natural gas vehicles (NGV's) were analyzed to compare the rapid GC method with the standard GC method, which required 40-minute analyses on two different instruments. In general, evaluation of the commercial prototype from Separation Systems, Inc., indicates that a high speed, high resolution gas chromatograph can meet the need for fast, efficient exhaust hydrocarbon speciation.
Technical Paper


THIS description of the hydraulic control used with the hydra-matic transmission reveals how the control operates to change ratios under power without direction from the driver. The control's pattern of automatic shifting for ordinary, high-range driving has been selected as the best compromise between top performance and low ratio of engine noise to wind noise. The control's low range shifts gears according to performance dictates alone, furnishing greater power for extreme conditions at low speeds and enabling the driver to use his engine as a brake on steep descents. Heart of the control system is a double hydraulic governor, sensitive both to car speed and throttle opening. THIS paper, as well as the two that follow, one by Messrs. Nutt and Smirl and the other by Mr. Kimberly, make up a symposium on automatic transmission components presented at the 1947 SAE Summer Meeting.
Technical Paper

Interrelationship of Design, Lubrication, and Metallurgy in Cam and Tappet Performance

A PROGRAM was undertaken to evaluate the performance of cams and tappets as influenced by design, lubrication, and metallurgical techniques. Car and dynamometer tests and a newly developed bench test are described. The latter shows promise in lending itself to the determination of the effects of single variables in a practical, short, and economic fashion, while the former do not. For the conditions of high contact stress and boundary lubrication experienced in cam and tappet operation, the authors draw several conclusions from the test work described, categorically related to the design, lubrication, and metallurigical problems present.
Technical Paper


USING a high-speed motion picture camera, flame photographs were taken of the combustion process associated with the starting of hot gasoline engines. Compression ignition at isolated points followed by normal combustion caused peak cylinder pressures to occur prior to top dead-center under some low-speed engine conditions. In addition, an abnormal combustion phenomenon was observed in the last part of the charge to burn. The reaction rate was appreciably faster than normal for the engine speed and much slower than is usually observed in knocking combustion at normal engine speeds.
Technical Paper

some metallurgical aspects of … Pontiac V-8 Engine Pearlitic Malleable Iron Crankshaft

PEARLITIC malleable iron crankshafts are being used in the new Pontiac engine as a result of recent developments. This paper discusses the physical properties of pearlitic malleable iron such as elastic modulus, fatigue endurance, and tensile strength. According to the author, definite machining economies result from using pearlitic malleable iron crankshafts.
Technical Paper

Diesel Exhaust Odor Its Evaluation and Relation to Exhaust Gas Composition

TECHNIQUES, based on panel estimates, were developed for evaluating the odor and irritation intensities of undiluted diesel-engine exhaust gases or of various dilutions of these gases in air. Along with the estimates, chemical analyses were made to determine the concentrations of total aldehydes, formaldehyde, and oxides of nitrogen. Statistically significant correlations were found between odor or irritation intensity estimates and the analytical data, but these correlations were too weak to permit accurate prediction of odor or irritation from chemical analyses. Effects of some engine variables on diesel odor were studied. Possible means of reducing diesel odor are discussed.
Technical Paper

Vapor-Locking Tendencies of Fuels A Practical Approach

THIS paper describes what the authors consider to be a simplified method of determining the vapor-locking tendencies of gasolines. The study of vapor lock was undertaken after they found the Reid vapor pressure method to be inadequate. The result of their work was the development of the General Motors vapor pressure, a single number which predicts vapor-locking tendency. The authors point out the following advantages of the new method: It allows direct comparisons of vapor-lock test results of different reference fuel systems; establishes distribution curves of volatility requirements of cars for vapor-lock free operation and of vapor-locking tendencies of gasolines; is a common reference value for both petroleum and automotive engineers. Finally, it more realistically evaluates the effects of small weathering losses on vapor-locking tendency than does Rvp.
Technical Paper


THIS paper describes the springs, control system, and ride of the air suspension system on the 1958 Buick. The system is a semiclosed one, providing a variable-rate suspension, automatic leveling and trim control, and manual lift. The latter feature is a knob below the instrument panel which can be operated when necessary to cope with unusual clearance conditions. The car remains at the same height with loads of up to five passengers and 500 lb in the trunk. The authors describe the road-holding ability of a car with this suspension system as excellent.
Technical Paper

Studying Valve Dynamics with Electronic Computers

Dynamic conditions of automotive type valve trains have been investigated by means of digital computers. It has been possible to include the effect of such nonlinearities as valve lash, linkage separation, valve seating, and valve spring surge. Comparison with experimental results has shown that computer solutions are realistic. The advantage of being able to simulate and predict performance of any proposed type of valve train is obvious. This paper presents methods of approach for analyzing valve dynamics, correlation of computed results with experimental values, and examples of application of interrelated methods. Included in this paper are: (1) Methods of approach for analyzing valve dynamics, (2) Correlation of computed results with experimental values and, (3) Examples of application of interrelated methods.
Technical Paper

Engine Crankcase Pumping Flow Model

A transient, one-dimensional, two-phase (crankcase gases and liquids) flow network model was developed (and coded in FORTRAN) to calculate the crankcase pressures versus crank angle during engine operation and the consequent crankcase pumping mean effective pressure (CPMEP). The two-phase flow was represented by an empirical expression. Note, CPMEP is one of the components of engine FMEP (friction mean effective pressure) and is being introduced here as a new term. The model was calibrated with engine crankcase pressure measurements. The motivation for the present work was the fact that no commercial (or public domain) software is available to adequately address this subject in sufficient detail. The model also predicts that closing (i.e. sealing) the individual bays of an engine can result in (nearly) zero CPMEP. This was confirmed by motored single cylinder engine measurements.