Search Results

Predictable and unpredictable forces will change the direction of the charge-air systems industry. The driver of diesel engine development will be the stringent emissions regulations of the 1990s. The drivers in the gasoline engine market will be improved fuel economy, performance, durability and emissions. Forces will also influence the charge-air marketplace, including changes in emission standards, national fiscal policies, political issues, fuel prices, alternate fuels and consumer tastes. The world community mandate for engines that are clean, quiet, durable and fuel efficient will be satisfied, increasingly, by first-tier component suppliers developing integrated systems solutions.

Synthesizing different customer and functional requirements into an acceptable design configuration within a given space constraints is a challenging task for design engineers. The principles for designing efficiency, noise levels, maneuverability, safety, durability, etc. into the product are well understood. However, designing for reliability, maintainability and quality turns out to be a long-drawn laborious process due to unavailability of simplified design procedures. The author in this paper develops the understanding of reliability, maintainability and quality design principles and methods for products, with specific reference to vehicle designs.

An inexpensive driving simulation system with sufficient fidelity has been developed. The system produces motion cues of four degrees of freedom, visual and auditory cues, and control feel on the steering wheel. This paper describes the features of this newly developed system and gives examples that demonstrate its effectiveness. The motion cues provided in this system are yaw, heave, and lateral and fore/aft accelerations. The lateral and fore/aft accelerations are simulated by tilting the simulator compartment. A computer-processed road image is given through a CRT monitor. The restoring torque of the steering wheel is produced by an electrical servosystem via a coil spring. Cruising sound is given in order to improve speed perception. Since the system uses digital computers, the vehicle characteristics are altered easily by merely rewriting the software. This enables us to simulate special vehicle dynamics such as front & rear wheel steering.

There is a strong interest around the world in natural gas as an alternative fuel. This paper is concerned with the option of converting diesel engines to spark ignition operation. Although this may appear to be an outrageous thermodynamic action, it is preferable to using natural gas in a low compression gasoline engine conversion. An investigation is described in which engine maps were produced for a 5.6 litre direct injection diesel engine converted to CNG. The diesel operating characteristics have been compared with those of the spark ignition conversion at compression ratios of 18:1 (the original diesel value), 15:1 and 13:1. Detailed data are presented for the 15:1 compression ratio. These test results are supplemented by results for other diesel conversions. The use of these engines in bus fleet operations is also discussed.

Many areas of the world are in various stages of development which frequently includes a rapid increase in the motor vehicle population. As a result, some areas are beginning to show the effect of increased motor vehicle use on air pollution. The vehicle's contribution to California's air pollution has long been recognized and studied, and measures have been implemented to reduce emissions from motor vehicles. The history of light duty vehicle emission control in the South Coast Air Basin of California is reviewed. Emission reductions achieved, current levels, projected future emissions and the need for further emissions reductions from light duty vehicles are discussed. For other areas of the world where motor vehicles contribute to air pollution, suggestions are made which can improve the effectiveness of emission control efforts; which should be consistent with political and economic realities, and efforts to achieve international harmonization of standards.

Motor vehicle standards in Japan was systematically established in 1951 for the first time. On the other hand, in Europe, the United States and Australia, etc., there are EEC directive, FMVSS and ADR, etc. However, it is desirable to harmonize these standards as harmonization of motor vehicle standards will contribute to the improvement of productivity for motor vehicle development and manufacture. As for the international harmonization, ECE WP29 has been playing a key role. Therefore, Japan has positively supported the standard harmonizing activities of ECE WP29. We must promote the international harmonization in co-operation with ECE WP29.

A survey of the in-service fuel consumption of passenger vehicles and derivatives in the Australian fleet was carried out in 1984-85. Seven hundred and four owners across Australia took part in the survey. Vehicle owners reported by questionnaire the amount of fuel used during four tank fills of normal operation, the distance travelled, and other details of the operating circumstances. The survey shows a clear downward trend in the fuel consumption of the Australian passenger fleet. The data also provides comparisons of actual fuel consumption obtained on the road, with laboratory derived values for fuel consumption. Vehicles in a sub-set of 40 were fitted with fuel flow meters during the survey and tested to Australian Standard 2077 for fuel consumption. The questionnaire method is shown to be a valid and accurate technique for determining in-service fuel consumption.

To improve the cold startability of methanol, methanol-butane mixed fuel was experimented. Engine performance and exhaust emissions are obtained with methanol-butane mixed fuel. These characteristics are compared with those of methanol and gasoline. The mixing ratios of methanol and butane are 50:50 (M50), 80:20 (M80), and 90:10 (M90) based on the calorific value. As a result, M90 produces more power than gasoline and more or less than methanol depending on the engine speed and the excess air ratio. Brake horse power of M90 is higher than that of gasoline by 5 - 10 %, and brake specific fuel consumption is smaller than that of gasoline by 17 % to the maximum based on the calorific value. NOx emission concentrations for M90 are lower than those for gasoline and higher than those for methanol because of the effect of butane, CO emission concentrations are somewhat lower than those for methanol and gasoline.

In order to achieve lean burn engine control system, it is necessary to develop high accuracy air fuel ratio control technology including transient driving condition and lean burn limit expansion technology. This paper describes the following. 1 The characteristics of the transient response of the fuel supply are clarified when various kinds of air flow measuring methods and fuel injection methods are used. 2 To achieve stable combustion in lean mixture, fine fuel droplet mixture, whose diameter is less than 40 μm, needs to be supplied.

Unsteady laminar flame propagation confined in a closed cylindrical combustion bomb is studied by numerical computation for an axisymmetric two-dimensional laminar flame. Computation includes complete two-dimensional unsteady Navier-Stokes equations of change for a chemically reacting propane-air mixture. Implicit Continuous fluid Eulerian, Arbitrary Lagrangian Eulerian finite difference technique, simplified reaction kinetics models, and artificial flame stretching transformation and inverse transformation were adopted in the calculation. Physically realistic flame behavior can be demonstrated even with rather coarse computing cell size, simplified reaction kinetics models, and personal computer level low power computing machines.

A procedure has been developed for evaluating equivalent drive cycle emission results from raw exhaust gas emissions data obtained from an engine under test on a computer controlled Vehicle Simulator Engine Dynamometer. The emitted species data is integrated with the air intake flow rate to determine the total mass of emissions, after correcting for the reduction in exhaust gas mass due to precipitation of the moisture of combustion. This procedure eliminates the need for the Constant Volume Sample (CVS) System attached to the vehicle exhaust while undergoing simulated drive testing on a chassis dynamometer to evaluate compliance of the test vehicle with the Australian Design Rules, ADR27 and ADR37. Sources of error with the procedure are examined by comparing the fuel consumption measured using a volumetric technique during the test with that evaluated by a carbon balance procedure as given in the Australian Design Rules.

An all-ceramic swirl chamber has been developed and analyses and evaluations concerning the strength of silicon nitride ceramic (Si3N4) have been performed with a view to using it for the entire internal wall surface of the swirl chamber. The strength characteristics of Si3N4 and their effect and variation have been determined. On the basis of measurements and analyses of thermal stresses, assembling stresses, etc., investigation of the most suitable construction and assembling methods to reduce load stresses on ceramic, and various kinds of duration tests, the swirl chamber has been confirmed to have the required durability. This engine was found to comply with the 1987 U.S. diesel particulate regulation.