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A discussion of reciprocating engine combustion research needs is presented. Results of a survey ranking 31 specific research topics are also given. The twenty-three respondents gave the five highest grades to; particulate formation and oxidation mechanisms, high temperature ring friction, end gas heat transfer and high pressure transient fuel spray studies.

A variety of exhaust emission regulations exist in the world today, establishing different testing procedures (many with different driving cycles) and emission limits. Vehicle manufacturers competing in the international marketplace must develop technologies to meet the mandated performance levels, and then run different tests to demonstrate compliance. In addition, manufacturers face different national administrative and production conformity requirements. The need for so many different procedures is questioned. Technologies to meet current emission requirements divide the world markets for passenger cars and light commercial vehicles into two divisions, one where catalytic converters and unleaded gasoline are needed and the other where leaded gasoline can be used. Adoption of a single test and compliance procedure for each of these two situations is proposed. The advantages of such harmonization are discussed.

The wear resistance of magnesium alloys has been significantly improved by the incorporation of hard ceramic particles to produce a composite. These composites can be processed by standard casting techniques, specifically die-casting. This paper discusses testing techniques for measuring the effect of the ceramic particulates on the composite's mechanical properties. Prototype part testing is also discussed.

The continued expansion of alcohol use in Brazil, to replace gasoline as fuel for Otto internal combustion engines, has led to the technological development of these engines. However, despite the progress achieved in fuel economy, driveability, corrosion resistance, etc., no comparable progress has been achieved in air pollutants emission control. This paper presents an overview of the alcohol automotive use in Brazil and discusses its air pollution related aspects.

A Tapered Element Oscillating Microbalance (TEOM) was used to measure transient diesel particulate emissions. Light duty IDI and DI engined vehicles were tested over the LA4 Drive Cycle. One vehicle, a 1.6 litre IDI diesel engined VW Golf (Rabbit), was also tested over the Japanese 10-mode and European ECE-15 Cycles. Transient particulate emissions were also measured from a heavy duty DI diesel engine tested according to the US Federal Heavy Duty Transient Test Procedure. The TEOM proved to be very flexible, permitting continuous particulate measurements to be made at each of the conditions studied. Particulate mass determined by the TEOM over a complete cycle was generally lower, typically by between 13 and 28%, than that measured using conventional gravimetric filtration procedures. A new calibration technique was devised which improved the correlation between TEOM and gravimetric results.

Part of the break-in facilities of a heavy-duty engine production plant were equipped with ceramic monolith trap oxidizers, most of which were catalyst-coated. Non-carbon particulates from the combustion of diesel fuel and lubricating oil as well as dust and wear particles from the engine caused the porous ceramic walls to become plugged very quickly. The deposits not only caused an unacceptable fast rise in exhaust back pressure, but an even faster deactivation of the catalyst by covering its effective surface. Due to their high sensitivity with respect to plugging and for cost-effectiveness reasons, ceramic monolith trap oxidizers appear to be unsuitable in applications where the emission of non-carbon particulate matter is extremely high, as is the case during engine break-in.

A single cylinder TACOM-LABECO open chamber diesel engine with a special research head, which incorporates an American Bosch Electronic Fuel Injection System, was used to study the effects of air swirl, injection pressure and nozzle geometry on exhaust particulates, NOx emissions, ignition delay, heat release and local heat flux measured at two positions on the head. Air swirl was varied from 0.8 to 4.5 swirl ratio by use of a shrouded intake valve. Peak injection pressure was varied from 35-114 MPa. Five different nozzle geometries were tested. All data were taken at a fixed engine operating condition of 2000 rpm and 0.5 equivalence ratio with an inlet pressure of 1.5 atm and nominal inlet temperature of 340°K.

The correlations between the physical properties and autoignition parameters of several alternate fuels have been examined. The fuels are DF-2 and its blends with petroleum derived fuels, coal derived fuels, shale derived fuels, high aromatic naphtha sun-flower oils, methanol and ethanol. A total of eighteen existing correlations are discussed. An emphasis is made on the suitability of each of the correlations for the development of electronic controls for diesel engines when run on alternate fuels. A new correlation has been developed between the cetane number of the fuels and its kinematic viscosity and specific gravity.

Three crude shale oils were chosen from six candidates to investigate their possible use as substitutes for No. 2 diesel fuel. Satisfactory hot engine operation was achieved on the crudes using a fuel heating system, allowing emissions characterization during transient and steady-state operation. Regulated gaseous emissions changed little with the crudes compared to diesel fuel; but total particulate and soluble organics increased, and larger injector tip deposits and piston crown erosion were observed. After engine rebuild, two minimally-processed shale oils were run without the fuel heating system, causing no engine problems. Most emissions were higher than for No. 2 fuel using an SO percent distillate of crude shale oil, but lower using a hydrotreated form of the distillate.

This paper describes the friction characteristics of a 1.8 Litre J-car piston and ring assembly as influenced by oil rings of conventional design, but of varying tensions. In addition, the piston-ring assembly friction characteristics are reported for a set of oil viscosities ranging from 2 to 20 cSt with and without a molybdenum friction modifier. Multigrade oil results are shown also. Finally comparisons are presented between changes in friction measured by the Instantaneous IMEP Method and those measured by the dynamometer for the engine as a whole. Our results show large differences in piston-ring assembly friction as oil ring tension was varied. However, these differences became moderate after the oil ring broke-in. Both high and low oil viscosities increased piston and ring assembly friction. The friction modifier was most effective with a mid-range viscosity and provided virtually no benefit at viscosity extremes.

High speed swirl chamber diesel engines having been developed to a high level of performance have always needed starting aids. By optimising both plug temperatures and position, it has been demonstrated that good start-ability can be achieved with plugs having a very low thermal inertia and therefore rapid warm up capability. The design of this new starting aid Lucas CAV (Micronova) which concentrates the heat at the tip of the plug enables good starting to be achieved without the plug having to extend to the centre of the chamber. Removal of the obstruction to swirl presented by conventional sheathed element plugs mounted in a horizontal position or the relocation of the plug in the vertical position have enabled the Ricardo Comet combustion system to be reoptimised giving a significant improvement in fuel economy coupled with very low part load smoke with the obvious benefit of reduced particulate emissions.

Existing low cost accelerometers for automotive applications are generally used for knock sensing. They are of two types : sensors with a resonance frequency corresponding to the knock frequency; sensors with a flat response in a large frequency domain. The sensors of the second type are particularly interesting because they are usable for any value of knock frequency, and so, for any type of engine. Unfortunately, the test of these sensors reveals that the frequency response has quite large dispersions in at least two frequency zones. Consequently, the response is not as flat as supposed. A new low cost piezoelectric accelerometer has been developped by RENAULT and RENIX. For this sensor, described in this paper, several new tricks applied in the sensor design, contribute to a very flat frequency response up to frequencies as high as 15 KHz.

Cyanide plating can be an environmental and economically acceptable process through the use of high vacuum, low temperature evaporators employing counterflow rinse tanks with water/water heat pumps to achieve high energy efficiency. The paper presents the airline plating forum with detailed information on the process, particularly as applied to cold bath cadmium plating essential to airline maintenance. An auxiliary chiller provides a method of stabilizing carbonate build-up in closed loop cyanide recovery systems, and can employ the hot end of the heat pump to force bath evaporation or provide hot water for final rinsing. Heat pump evaporators employing auxiliary solar heat and waste heat are also described. These new energy effective systems provide the plating industry with a method of circumventing the escalating costs of hazardous sludge disposal.

A two-dimensional model for the simulation of flow and premixed combustion in engines is extended to include a knock sub-model. An autoignition model based upon a degenerately branched chain mechanism /14/ was modified for this purpose. Rapid-compression machine experiments could be reproduced as well as engine knocking tendencies. The coexistence of the new knock model and the overall combustion model of Arrhenius type was arranged by a suitable switch-off criterion for the autoignition reactions. Simulation of pressure waves and respective flowfields under knocking conditions are also shown to be possible. A parametric study of the influence of engine geometry, EGR and swirl on knocking tendency is presented.

During combustion in a diesel engine radiation heat transfer is the same order of magnitude as the convection heat transfer. Therefore for a reliable engine simulation the radiation transfer equation should be solved simultaneously with the flow and energy equations. A rigorous solution for the radiative transfer is, however, neither warranted nor cost effective. An approximation is needed at a level consistent with those used in modeling the fuel spray, the chemical kinetics, the soot and the turbulence. The approximation should account for the anisotropic behavior of radiation in the engine and be easily integrated into finite difference codes. This paper illustrates use of the first and the third order spherical harmonics approximation to the radiative transfer equation and the delta-Eddington approximation to the scattering phase function for droplets in the flow.

The motion of occupants under the conditions of traffic accidents can be described in more or less extensive simulation models. For the evaluation of loadings on occupants, it is indispensable to include all exterior forces (e.g. seat forces) which have influence on motion behaviour, as well as contact models which describe contact forces during impact (e.g. against the steering wheel). In component tests, seat belt material, steering wheel and seat were examined; force/deflection characteristics were derived from these experimental results. Utilization of these dynamic charateristics in simulation models results in a realistic description of the motion of the occupant. In this way, mechanical loads on the occupant can also be evaluated, this enabling the assessment of risk of injury.

On the basis of extensive representative traffic accident material (car-to-car and single car accidents) the focal points of real-life accidents were ascertained. The different accident configurations were classified into collision types, and the order of importance was determined according to the frequency of occurrence and the injuries which resulted- In the light of the distribution function of vehicle mass and collision speed, boundary and reference values of a “substitute accident system” were ascertained from real-life accidents. Extensive and detailed studies of accident and car parameters were necessary to provide realistic conditions for the crash tests. The dummy loading values measured in the crash test or calculated by means of a simulation model were compared with real-life injuries in the appropriate mass and speed class.

Optimum deformation structures for the safety of passengers of motor vehicles are worked out on the basis of computer generated accident simulations. The simulated accidents are based on accident statistics and consider the relevant collision types as well, as the actual mass and speed distributions. The evaluation of the deformation structures include the injury-related costs and the effect domain costs. These costs also consider the determinable results of modified deformation structures such as increased fuel consumption. As the final result, it can be stated that the effect domain costs have a dominant influence. Furthermore, the protective measures for increased safety during side collisions are best taken in the frontal area of the impacting vehicle.

When the gap between the seat belt and occupant's body is considered, it is of vital importance that the seat or the seat belt has sufficient energy absorbing functions. In this con-connection, it was found that the ideal energy absorbing pattern to stop the vehicle was to provide greater deceleration at the first phase of impact and less deceleration at the second phase to be followed by slightly greater deceleration at the last phase of impact. The authors proposed and designed a special bumper capable of simulating this ideal deceleration pattern applicable over a wide range of pre-collision velocities. The performance of the new bumper was verified by a series of experiments using a test vehicle with a belted dummy.

Although computer simulation is regarded primarily as a tool for systems analysis, simulation can also be used in the process of systems optimization. This paper describes recent enhancements to a computer program package which enables the use of vehicle and occupant simulation models in determining the design of vehicles and restraints for maximum occupant impact protection. Also described is an application of this program package to determine the optimal design of a passenger vehicle involved in frontal collisions.