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Crankshaft bending vibration was investigated with a computer simulation technique. First, the crankshaft bending vibrations are briefly explained. Second, some critical points of theoretical analysis including gyro-scopic term and effect of shaft asymmetry are explained. Finaly, the crankshaft system is modeled by a transefer matrix and calculated. The results showed good correlation with the experimental data.

The behavior of a V-belt CVT was investigated analytically and experimentally. It was found that as the torque load increased, the belt radial displacement increased in radial inward direction for the driven pulley while the radial displacement decreased slightly and increased for the driver pulley. The relative belt displacement for the driver was negligible compared with that of the driven. The experimental results were in good accordance with the theoretical results except for the inlet and exit region of the pulley. The speed ratio-torque load-axial force relationship derived from the belt behavior analysis also showed good agreement with the experiment. It is suggested that the results of this paper can be used as basic design materials of a V-belt CVT.

This paper describes Computer Aided Expert System for Designing transmission. Design knowledge is classified into 2 groups - “CLASS FRAME” showing the concept relative with subject of study and “INSTANCE FRAME” displaying some examples together with knowledges in the form of diagram defined on frame as image data. These data were hierarchically sorted out for problem reduction and very effective and easy to understand knowledge representation was achieved. Besides that, experimental knowledge was processed by either probability theory based on parameter of certainty factor determining the quantity of specified information by using predicate logic or fuzzy inference using membership function both of which, in turn, made it possible to obtain reasonable and still yet optimum answer. Expert tool of personal computer can be employed for this system, and external program such as gear specification calculation program or gear stress calculation program can be executed by any user.

The recent decision taken in the USA to further reduce the exhaust emissions from vehicles means a technological challenge for both the designers of engines as well as for the developers of catalytic exhaust aftertreatment systems. A powerful approach is the simultaneous optimization of the engine raw emissions, of the exhaust pipe and catalytic converter design and of the catalyst formulation. The paper aims at demonstrating this by means of two examples. New washcoat formulations for Platinum/Rhodium and for Palladium/Rhodium based monolithic catalysts were developed to reach both an improved conversion performance and a better durability. These catalysts were first evaluated in a model gas reactor using different hydrocarbon species, which were defined by detailed analysis of the vehicle raw emissions during the FTP-75 test cycle. The catalysts were then evaluated on an engine dynamometer, in the fresh and the engine aged state.

This paper explores the feasibility of the catalytic converter with an alloy honeycomb monolith carrier for light duty cross country vehicle. In accordance with special operating condition of light duty cross country vehicle, the purification function of the catalytic converter must be effective, and the vibration stength of the catalyst carrier must be strong enough as well, so that the carrier would not break to block up the exhaust passage when the vehicles are bumping along a rough road or when they are being cooled down rapidly in fording water pools. On the basis of dispersing pattern of the thermo-strain after the carrier is heated extremely, the form of feeding of carrier is improved significantly, so that if by any chance the catalyst is working overloaded, the carrier can still retain original honeycomb after it is sintered. It doesn't interfer with normal running of vehicles, because the flow resistance of exhaust gas is not increased.

First Automobile Works (FAW) has successfully developed two kinds of cold forming techniques by a single, stroke in one station. One is called punch-and-close extrusion technique, by using this process we can produce cup parts with flangs. For example, wheel hub nuts of trucks are used to be extruded four times on a multi-station extruder, but now it can be done by a single stroke in one station. The investment on equipments for the new technique is only one-tenth of that multi-station extruder, and the quality of the products is improved a lot. The other is called spline forming technique by a single axial extrusion stroke. These cold forming techniques have the following advantages, the simple equipments required, high efficiency and good product quality. So they will be widely used in auto manufacturing industry.

The explication of characteristics of a driver is a basic theme in the field of vehicle engineering, and many studies have already been carried out. But characteristic of man is much more complicated than that of machine and characteristics described by one method could only express one aspect of a driver. Therefore, it is necessary not only to deepen our studies of the former methods but also to look for new ones. In this study, Neural Network System(NNS) is applied to a driver model. NNS is a parallel processing system which was designed as one type of the models that simulate the information processing in the brain. One of the advantages of this model is that the system itself is generated automatically according to the combination of input and output data. The purpose of this study is to propose an example for the basic method of the construction of a driver model using NNS and to show the application of it.

In Japan, as the dust produced from studded tires which scratch up paved surfaces is polluting the environment, the use of studded tires will be prohibited throughout the country in the near future. High performance studless tires are being developed for this purpose, but users are worried about their use, and traffic authorities are worried about the increase of accidents. The authors performed a series of experiments to evaluate the braking, driving and hill climbing performance of winter tires. It was found that the braking stiffness of studless tires is better than studded tires in the slip ratio range of 20 to 40%. In friction tests using a piece of rubber and ice, water was not formed in the contact surface below −10°C. It was also found that the friction coefficient of rubber increases with softer rubber. As a result, if a tire is designed to have a soft tread and large contact area with the road surface, we may safely replace studded tires with studless tires.

An analytic method is attempted to optimize the body structure of a passenger car by the quantitative prediction of crashworthiness from the early stage of vehicle development. PAM-CRASH, one of explicit nonlinear finite element programs on market, is used as a tool for crash simulation in the present work and a finite element full-car model for frontal crash analysis is developed with reference to an established car. The reliability of the present simulation method and the pertinence of the developed finite element model are examined carefully by comparing the numerical simulation results of various kinds with the corresponding test results. With the finite element model validated with test results, attempts have been made to improve the crashworthiness by modifying the body structure.

The influence of aromatic content in fuels on the soot and NOx emissions from a diesel engine was analyzed under controlled ignition lags with spark-assisted operation. Monocyclic aromatic hydrocarbons and n-hexane mixtures were used as fuels, and the aromatic content was varied from 0 to 75 v-%. The experiments showed that, at the same equivalence ratio and regardless of the molecular structure of the fuel, the soot concentration in the exhaust gas could be described by a linear-combination function with two variables representing the ignition lag and C/H atom-ratio of the fuels. For unchanged ignition lags, the soot emissions increased linearly with increased C/H atom-ratios, which are controlled by the aromatic content. The degree of increase in soot emissions with increasing C/H atom-ratio decreased with decreasing equivalence ratios. The NOx emission increased slightly with increases in the C/H atom-ratio and ignition lag.

It was shown in our previous study that the air-jet in the late combustion period reduces the diesel exhaust soot effectively. However, the plunger-pump type air-jet generator used in our previous study has a big power-loss. In this paper, the reduction of soot emission with a newly designed air-accumulation type air-jet generator is investigated using an experimental single cylinder engine. The optimum design parameters, such as the spring constant and the air outlet diameter, are examined experimentally. The effectiveness of the air-accumulation type air-jet generator for the reduction of soot and NOx emission is about a half of that of the plunger-pump type. It is confirmed that the disappearing speed of the luminous flame region accelerates with the increase of the heat-release in the late combustion period.

The dual fuel engine is a means for utilizing gaseous fuel resources efficiently in diesel engines after appropriate conversion. These converted engines can provide an effective method for producing power while reducing exhaust emissions, especially exhaust particulates and oxides of nitrogen. More efficient and increased power output relative to the corresponding diesel operation can be achieved with dual fuel engines at relatively high load. The light load performance, especially with high gas to diesel fuel ratios, remains relatively inferior. Poor fuel utilization efficiencies and high unburnt hydrocarbons and carbon monoxide exhaust concentrations are readily encountered at light loads. This trend has necessitated usually the resorting back to diesel operation at idling and very light load conditions. The paper describes the combustion phenomena that bring about these limitations at light load.

A first retrofit conversion of a Cummins NTC335 engine to spark ignition was carried out in New Zealand in 1984. The conversion used widely available technology for stoichiometric control of natural gas fuel - air mixtures. Experience from the on-road application in a 40,000 kg GVW truck contributed much to the later development of a 400 hp gas-fuelled variant of the same engine family, using lean mixture carburettion control. A second engine entered service in a logging application in February 1989. The following paper summarises results arising from laboratory testing of the second engine, and from in-field monitoring. Also presented are preliminary results from testing of a third generation engine, using timed multi-point injection of gas fuel.

The preignition processes in a dual fuel engine are described and the roles of the formation and consumption of formaldehyde in these and subsequent processes are discussed. Reference is made to the results of detailed chemical kinetic modelling of the oxidation reactions of the gaseous fuel component during the compression stage. This is supported by experimental evidence of the kinetic role of formaldehyde through its deliberate induction with the intake charge of a dual fuel engine over a range of operating conditions and fuels. It is suggested that the preignition reaction activity of the gaseous fuel-air charge during compression contributes significantly to the observed extension of the ignition delay in dual fuel engines at very low load conditions when relatively small gaseous fuel concentrations are being used.

The dual requirement of high conversion efficiency and 50K mile durability for cordierite ceramic converters is achievable through optimization of washcoat and catalyst formulation. This paper presents new data for high temperature physical properties, light-off performance, conversion efficiency and pressure drop through an oval cordierite ceramic converter with triangular cell structure and two different washcoat formulations; namely standard vs high-tech. Both of the washcoat systems have a beneficial effect on strength properties with nominal impact on thermal shock resistance. Both the standard and high-tech catalysts provide identical light-off performance for CO, HC and NOx conversion. The high-tech washcoat and catalyst system, in particular, provides consistently superior conversion efficiency for CO, HC and NOx. The pressure drop across the catalyst depends on hydraulic diameter and is only 8% higher for high-tech washcoat than for standard washcoat.

Pressure-loss characteristics of a variety of single- and double-substrate metal-foil and ceramic-substrate converters with tapered and truncated inlet and outlet headers were measured in room-air flow, hot-gas flow, and engine-exhaust tests. Test data in the three different media correlated with the inlet-pipe Reynolds number when expressed as a loss coefficient, i.e., pressure loss normalized by the inlet-pipe dynamic head. Because restriction measurements made in different media correlate well as a Reynolds number-dependent loss coefficient, inexpensive room-air test data can be used to estimate converter pressure losses in the engine environment. The normalized losses in the substrate varied inversely with inlet-pipe Reynolds number, ranging from, e.g., 6 at Re = 30 000 to 2 at Re = 200 000. The remainder of the losses occurred in the inlet and outlet headers and in the section between the substrates.

The long-term durability of a ceramic racetrack converter is examined using the systems approach. Each of the converter components is characterized with respect to its behavior under simulated mechanical and thermal loads. In particular, the impact of three different washcoats on key physical properties, and the load vs. deformation characteristics of three different insulation mats are examined from mechanical and thermal durability point of view. Similarly, the can deformation at elevated temperature is taken into account to ensure adequate mounting pressure on ceramic monolith under all operating conditions. The temperature distribution at the midbed of the catalyst during engine dynamometer testing, together with the component properties data, are then used in a finite element model to compute thermal stresses in the monolith as function of engine load and speed.

A 15″ diameter x 15″ long, EX-47 wall flow diesel exhaust particulate filter, was operated for approximately 5000 hours on a load haul dump vehicle (LHD) in an underground mine. LHD's are an integral part of production in most underground mines and characteristically operate at high power and load conditions for a significant part of their overall duty cycle. The vehicle was equipped with a Caterpillar 3306 PCTA engine. Fuel containing 0.2 wt% (or less) sulphur and engine oil specified at 0.025% ash were used. Following removal from the vehicle, the filter was analyzed to evaluate physical and thermal properties of the cordierite diesel filter as well as to inspect for ash accumulation or damage. The filter was found to be in excellent physical condition, however ash accumulation was high. The ash was found to be richest in Ca, Zn and P.

Engine tests have been conducted to establish the ignition delay period of two representative diesel fuels of cetane ratings 40 and 50, and of the lower rated fuel blended with additives. The latter included six organic peroxides, of different chain length and structure, two nitrates and mixtures of additives. The primary role of the additives appeared to be that of heat generation through rapid, exothermic, oxidative degradation following injection to the cylinder. A beneficial degree of synergism was noted with certain mixtures of peroxide and nitrate additives.

Analysis results of used oils sampled from many engines operating in the field show that the most critical factor governing the limits of oil use is insoluble fraction concentration in oil. Hence, the authors developed a new oil and by-pass oil filter to increase soot trapping efficiency, so as to extend oil change interval. Soot trapping efficiency could be improved from 30% to more than 80% using a bigger oil filter with fine mesh and a newly developed low soot dispersancy oil. Engine lubrication performance of the new oil was compared to that of standard and commercial long-drain oils by conducting 300-hour endurance tests on an 11.7 liter direct injection, turbocharged and aftercooled diesel engine at rated output. Test results proved superior engine lubrication performance of the new oil. THE INTERVAL between lubricating oil changes for diesel engines is twenty to forty thousand kilometers, depending on engine manufacturers' recommendations (1)*.