Showing papers in "Jsae Review in 2000"
TL;DR: In this article, the effects of EGR and intake heating with an exhaust to intake heat exchanger on engine performance and exhaust gas emissions were investigated, especially at low loads, and 3-CFD simulations were conducted to analyze the combustion process in the combustion chamber, using the KIVA-3 code.
Abstract: This paper deals with a diesel engine dual-fueled with natural gas. This system can achieve a high thermal efficiency at higher loads by utilizing the premixed lean natural gas mixture ignited by pilot-injected diesel fuel. At low loads, however, high THC emission and low thermal efficiency were observed. To resolve these problems, effects of EGR and intake heating with an exhaust to intake heat exchanger on engine performance and exhaust gas emissions were investigated, especially at low loads. In addition, 3-CFD simulations were conducted to analyze the combustion process in the combustion chamber, using the KIVA-3 code. The result indicates that thermal efficiency and THC emission at lower loads can be improved by intake air heating combined with EGR.
164 citations
TL;DR: In this article, the effects of fuel properties on combustion characteristics and emissions such as NOx, smoke, and particulate in a direct-injection diesel engine were investigated and the results showed that reducing cetane number resulted in the increase of NOx and the decrease of particulate at high load.
Abstract: This study investigated the effects of fuel properties on combustion characteristics and emissions such as NOx. THC, smoke and particulate in a direct-injection diesel engine. Cetane number and aromatic content of fuels were varied independently. The results showed that reducing cetane number resulted in the increase of NOx and the decrease of particulate at high load. The aromatic content had little effect on combustion characteristics. However, increasing aromatic content for high cetane number fuel resulted in high NOx and particulate emissions. For low cetane number fuel, increasing aromatic content produced high THC emission at retarded injection timing. In the case of high injection pressure, fuel properties showed little effect on particulate emissions.
162 citations
TL;DR: In this article, a new outside mirror which enhances rearward visibility on a rainy day has been developed using a TiO2-SiO2 coating on the glass base, which spreads out rain droplets on the mirror surface into a thin film of water by a photocatalytic hydrophilic effect in the TiO 2−SiO 2.
Abstract: A new outside mirror which enhances rearward visibility on a rainy day has been developed using a TiO2–SiO2 coating on the glass base. Prepared by the sol–gel process, the coating spreads out rain droplets on the mirror surface into a thin film of water by a photocatalytic hydrophilic effect in the TiO2–SiO2. This mirror maintains its good hydrophilicity for a long time, and when hydrophobic contaminations collect on the glass surface, the sun's radiation induces a photocatalytic effect that serves to decompose the contaminations. Furthermore, the new mirror has sufficiently high durability for use in the severe automotive environment.
69 citations
TL;DR: In this article, the authors studied two algorithms for road slope estimation to avoid needless shifting when vehicles with automatic transmissions are running uphill and downhill, and found that the former algorithm is expected to estimate road slope more accurately than the latter.
Abstract: We studied two algorithms for road slope estimation to avoid needless shifting when vehicles with automatic transmissions are running uphill and downhill. One algorithm makes an estimation using a longitudinal acceleration sensor and the other makes an estimation using estimated vehicle output torque. The former is expected to estimate road slope more accurately than the latter, but the former is more expensive because an additional acceleration sensor is needed. The two algorithms were implemented on the transmission control unit and compared experimentally. We found the latter could estimate road slope accurately enough to avoid needless shifting.
64 citations
TL;DR: In this article, the authors analyzed the thermal efficiency of a hydrogen premixed spark ignition engine and compared it with a conventional combustion engine with a constant volume combustion, and found that hydrogen combustion had higher cooling loss to combustion chamber wall.
Abstract: Hydrogen has higher flame velocity and shorter quenching distance than hydrocarbon fuels, and is supposed to have special characteristics in the combustion process of internal combustion engines. In this research, contributors to thermal efficiency in a hydrogen premixed spark ignition engine were analyzed and compared with methane combustion. Results showed hydrogen combustion had higher cooling loss to combustion chamber wall, and thermal efficiency of hydrogen combustion was mainly dominated by both cooling loss to combustion chamber wall and degree of constant volume combustion.
54 citations
TL;DR: In this article, battery development is discussed by examining the heat behavior analysis of Ni-MH batteries, and the report is broken down into several areas including battery reaction heat or electric heat.
Abstract: Nickel metal hydride batteries that have been developed since 1991 are used in the “HONDA EV PLUS” launched in California State in May, 1997. Batteries for electric vehicles are quite different from consumer batteries. Temperature, in particular, affects battery performance and cycle life remarkably due to the nature of heat generation of the battery itself. Accordingly, thermal management technology, including the development of battery materials, the structural design of the battery module or pack, and the installation method, is of the utmost importance. In this report, battery development is discussed by examining the heat behavior analysis of Ni–MH batteries. This report is broken down into several areas including battery reaction heat or electric heat.
43 citations
TL;DR: In this article, a methane direct injection stratified charge engine premixed with a hydrogen lean mixture was analyzed, and the results showed that the combustion system achieved a higher thermal efficiency due to higher flame propagation velocity and lower exhaust emissions.
Abstract: Characteristics of combustion and emissions in a methane direct injection stratified charge engine premixed with hydrogen lean mixture were analyzed. Results showed the combustion system achieved a higher thermal efficiency due to higher flame propagation velocity and lower exhaust emissions. An increase in the amount of premixed hydrogen stabilizes the combustion to reduce HC and CO exhaust emission, and increases the degree of constant volume combustion and NOx exhaust emission. The increase in NOx emission can be maintained at a lower level with retarded ignition timing without deteriorating the improved thermal efficiency.
43 citations
TL;DR: In this article, the authors describe a laboratory study of the influence of sound quality on the annoyance caused by road traffic noise and find that the contribution of high frequency contents of road traffic noises on annoyance was significant.
Abstract: This paper describes a laboratory study of the influence of sound quality on the annoyance caused by road traffic noise. To measure the annoyance caused by road traffic noise, two kinds of subjective evaluation tests were carried out under the exposure of artificially modified road traffic noise which was originally recorded in an urban area. One is a subjective evaluation test using a categorical scale of five steps for annoyance, and the other is a listening interference test for matching the loudness of replayed classic music under the existence of road traffic noise of various loudness. As a result, we found that (1) Contribution of high frequency contents of road traffic noise on annoyance was significant. (2) When noise exposure level was 70 dB(A) in Leq, the contribution of high-frequency noise to the listening interference was equivalent to 3 dB(A) under the exposure of various modified road traffic noise in their high-frequency contents. (3) Multiple regression models of annoyance were constructed by roughness and sharpness as well as Leq as their explanatory variables.
42 citations
TL;DR: In this article, the authors present a parametric study that was conducted on the basis of an analysis of airflow through the ventilation holes as well as a thermal stress analysis and a vibration analysis during braking.
Abstract: Critical performance requirements for a brake disc rotor include heat resistance, high cooling and low vibration. In trying to reduce the weight of the disc rotor, it is necessary to achieve a design with a good balance of performance capable of satisfying all of these requirements. This paper presents a parametric study that was conducted on the basis of an analysis of airflow through the ventilation holes as well as a thermal stress analysis and a vibration analysis during braking. Based on the relationships obtained between rotor weight, shape and each performance requirement, a method is presented for designing a lightweight disc rotor.
33 citations
TL;DR: In this paper, the authors proposed an aluminum hybrid body structure which has the advantages of both monocoque and space frame bodies, which achieved a high level of safety, performance and stiffness, as well as achieving cost savings.
Abstract: One of most essential factors to develop the highest gas mileage vehicle in the world is weight reduction of the vehicle body. Therefore, we replaced the traditional steel material for body in white (BIW) with aluminum. In order to apply aluminum to the BIW of a passenger car, the serious issues are cost as well as the technical challenges of the BIW performance characteristics. Finally we designed an aluminum hybrid body structure which has the advantages of both monocoque and space frame bodies. This resulted in the BIW weight a half of a traditional steel body, with the attainment of a high level of safety, performance and stiffness, as well as achieving cost savings.
32 citations
TL;DR: In this article, the trends of automotive fuel qualities in Japan were described and evaluated by comparing them with the fuel quality recommendations of the World Wide Fuel Charter (WWCFL), and they found that most gasoline properties, such as Research Octane Number (RON), Motor Octane Numbers (MON) and Distillation Temperature, remained almost constant.
Abstract: This paper describes the trends of automotive fuel qualities in Japan. It was found that most gasoline properties, such as Research Octane Number (RON) , Motor Octane Number (MON) and Distillation Temperature, remained almost constant. Although ASTM Cetane Index, Kineamitc Viscosity and 90% Distillation Temperature (T90) of diesel fuels increased, the other diesel fuel properties remained almost constant. Finally, we evaluated Japanese automotive fuel properties by comparing them with the fuel quality recommendations of the World-Wide Fuel Charter.
TL;DR: In this paper, the variation in oil film thickness of a piston-ring package measured with LIF on the piston thrust side in the sliding direction is described, and it is found that the oil control ring OFT differs significantly from the theoretical value in the early stage of the down stroke.
Abstract: This paper describes the variation in oil film thickness (OFT) of a piston-ring package measured with LIF on the piston thrust side in the sliding direction. It is found that the oil control ring OFT differs significantly from the theoretical value in the early stage of the down stroke. It is also found that OFT increases where the ring tangential tension is reduced, while it decreases where the ring width is reduced. The scraper ring OFT shows a tendency similar to the oil control ring throughout the cycle. The compression ring OFT is extremely thin around TDC due to oil starvation.
TL;DR: In this paper, a study was made of the possibility of reducing engine speed variation and engine block roll vibration by using a motor connected directly to the engine crankshaft, which showed a rectangular waveform change in synchronization with the crank angle allowed the smallest motor size.
Abstract: A study was made of the possibility of reducing engine speed variation and engine block roll vibration by using a motor connected directly to the engine crankshaft. Motor torque having the opposite phase of engine torque was applied to reduce vibration. It was found that motor torque which showed a rectangular waveform change in synchronization with the crank angle allowed the smallest motor size. The control technique that minimizes energy losses was also confirmed.
TL;DR: In this paper, a semi-corrective design concept for formulating friction materials so as to optimize the friction coefficient and reduce aggressiveness to the rotor through control of the friction interface between the pad and rotor is presented.
Abstract: The aggressiveness of friction materials to rotors in conventional braking systems tends to increase according to their friction coefficient, making it difficult to achieve effective braking performance while reducing cold brake judder at the same time. This paper describes a brake design technique that incorporates the following fundamental elements: (1) a semi-corrective design concept for formulating friction materials so as to optimize the friction coefficient and reduce aggressiveness to the rotor through control of the friction interface between the pad and rotor; (2) a caliper and rotor design method for reducing partial rotor abrasion in both braking and non-braking modes.
TL;DR: In this paper, the response lag during rapid steering in the hydraulic power steering system of a vehicle was analyzed with a numerical simulation mathematical model which considered the propagation of pressure waves in a hydraulic line and visco-elastic characteristics of the hose.
Abstract: Response lag during rapid steering in the hydraulic power steering system of a vehicle was analyzed with a numerical simulation mathematical model which considered the propagation of pressure waves in a hydraulic line and visco-elastic characteristics of the hose. Pressure perturbation by pump flow ripple and self-excited vibration which were incompatible with the response, were analyzed by the simulation. From these examinations, the mechanism of the response lag is clarified and the optimized dimensions of the flow control valve and the supply line which reduce the response lag, the pressure perturbation and the vibration were found.
TL;DR: In this article, a wheel skid detection method without chassis velocity for electric vehicle (EV) is proposed, which can sense the skid with only the values of current and rotating velocity of the motor.
Abstract: A novel wheel skid detection method without chassis velocity for electric vehicle (EV) is proposed. The proposed method can sense the skid with only the values of current and rotating velocity of the motor. The output torque of the motor is easily comprehensible, and the proposed method utilizes this advantage of EV. Estimation of vehicle chassis velocity or wheel absolute velocity is not required. The experiments were carried out with laboratory-made electric vehicle “UOT Electric March I”, and the results show the effectiveness of this method. We also carried out some simulations to discuss how to prevent the wheel skid with this skid detector.
TL;DR: In this paper, the authors developed a micro smoke meter which can measure locally the generating section and amount, and a method to calculate the accumulated soot weight from the smoke concentration.
Abstract: Thick smoke is exhausted from the tail pipe when starting or accelerating a diesel engine vehicle. This research showed that this phenomena is caused when soot accumulated inside the engine is eliminated. A major eliminating section for the DI engine is the cavity and for the IDI engine the combustion chamber. We developed a micro smoke meter which can measure locally the generating section and amount, and a method to calculate the accumulated soot weight from the smoke concentration.
TL;DR: In this article, the authors developed computer simulation models of the European Enhanced Vehicle-safety Committee (EEVC/WG10 and WG17) pedestrian subsystem tests for cars to assess pedestrian protection.
Abstract: The European Enhanced Vehicle-safety Committee (EEVC/WG10 and WG17) proposed three component subsystem tests for cars to assess pedestrian protection. The objective of this study is to develop computer simulation models of the EEVC pedestrian subsystem tests. These models are available to develop a car confirming the pedestrian subsystem test requirements. The pedestrian subsystem test models were developed and validated in this study. However, some improvements are still needed in these models to make them more reliable in simulating the pedestrian subsystem tests to develop a car confirming to the tests requirements
TL;DR: In this paper, a new aluminum alloy bearing that allows a higher wear resistance was developed for higher unit loads and higher temperatures, where the oil film thickness between bearing and shaft is increasingly thinner.
Abstract: The recent demands for higher performance and lower fuel consumption of automotive engines require the bearings to operate under severe conditions. As a result of these requirements, engine bearings are used under higher unit loads and higher temperatures, where the oil film thickness between bearing and shaft is increasingly thinner. One of the problems with conventional aluminum alloy bearings used under these conditions is the low wear resistance. For this reason, we have developed a new aluminum alloy bearing that allows a higher wear resistance. This paper describes the mechanism to upgrade the wear resistance and the performance of this new bearing material.
TL;DR: In this article, the relationship between the behavior of each brake component and drag torque was analyzed by measuring the displacement at several places on the brake caliper together with drag torque in the non-braking mode.
Abstract: Brake drag torque under non-braking conditions with the disc rotating freely causes fuel economy to decline and induces disc thickness variation, which gives rise to brake judder. In this study, the effect of the contact condition between the pads and the disc rotor on disc rotor wear was first studied. The relationship between the behavior of each brake component and drag torque was then analyzed by measuring the displacement at several places on the brake caliper together with drag torque in the non-braking mode. Based on the results, a design concept for reducing brake drag torque is presented here, along with a concrete mechanism for obtaining the desired reduction.
TL;DR: In this article, the authors investigated the potential of a new combustion system to reduce combustion noise and improve emission performance simultaneously, as a result of applying heavy EGR and retarding the injection timing, combustion excitation forces are reduced without any increase in exhaust emissions.
Abstract: The DI diesel engine has an advantage in terms of fuel economy, but disadvantages with respect to exhaust emissions and large combustion noise. To overcome these drawbacks, we have previously proposed the Modulated Kinetics (MK) concept [1] , [2] of low-temperature, premixed combustion. This paper presents the results of an investigation into the potential of a new combustion system to reduce combustion noise and improve emission performance simultaneously. As a result of applying heavy EGR and retarding the injection timing, combustion excitation forces are reduced without any increase in exhaust emissions, and with reduction of fuel injection system noise.
TL;DR: It is found that, although DAI has been widely believed to be cause by rotational impacts, it can also be caused by translational direct impacts due to the influence of internal head structures.
Abstract: This paper discusses the relation between head injury and the Head Injury Criterion (HIC), which is widely used as a vehicle crash safety standard, and considers the importance in traffic accidents of diffuse axonal injury (DAI), which exhibits symptoms of conscious disturbance. In our analytical study reported in this paper, we constructed a two-dimensional computer model reproducing an axial section of the human head to analyze causes of DAI. Simulation results of applying direct impacts to the head by an impactor are reported. We found that, although DAI has been widely believed to be caused by rotational impacts, it can also be caused by translational direct impacts due to the influence of internal head structures.
TL;DR: In this article, the performance of micro-grooved bearings with shallow circumferential grooves has been investigated by using elastohydrodynamic lubrication theory to calculate the bearing performance.
Abstract: To meet today's requirements for higher performance engine bearings, microgrooved bearings, that is plain bearings with shallow circumferential grooves, were developed. Recently, the performance of microgrooved bearings, obtained experimentally, were reported [1] , [2] . The authors calculated the bearing performance of the microgrooved bearings by elastohydrodynamic lubrication theory. In this paper, the authors describe theoretically the calculation method and the performance of the microgrooved bearings.
TL;DR: In this article, a study for improvement of sorting precision for metals and glass contained in Automobile Shredder Residue (ASR) was carried out, employing a sorting system including slant roller separation equipment, in order to increase recycling rate and reduce waste volume.
Abstract: A study for improvement of sorting precision for metals and glass contained in Automobile Shredder Residue (ASR) was carried out, employing a sorting system including slant roller separation equipment, in order to increase recycling rate and reduce waste volume. Compaction and solidification for ASR were also studied and optimal conditions were found.
TL;DR: In this article, a single-cylinder engine was analyzed by using the ion current and the pressure in several positions and the results of combustion observation, and the region where the ion probe catches the ions changes with the polarity and the power spectrum of the ion currents did not always agree with that of the pressure.
Abstract: Knocking in a single-cylinder engine was analyzed by using the ion current and the pressure in several positions and the results of the combustion observation. The region where the ion probe catches the ions changes with the polarity and the power spectrum of the ion current did not always agree with that of the pressure. When the shock wave arrived at the ion probe, the ion current rapidly increased the same as the pressure. It was understood that the ion current vibrates because the ion density changes with coarseness and minuteness of the pressure wave.
TL;DR: This study compares the behavior of bicyclists and pedestrians struck laterally by cars with MADYMO to determine whether the same effects may be obtained with respect to head protection for bicyclists.
Abstract: In Japan, bicyclists account for approximately 10% of all the victims killed in traffic accidents annually. This indicates that, in addition to accidents involving pedestrians, attention should be paid to these involving bicyclists. This study compares the behavior of bicyclists and pedestrians struck laterally by cars. Comparison is made based on accident analysis and computer simulations with MADYMO. Europe is moving toward enacting legislation regarding pedestrian head protection testing. This study also attempted to determine whether the same effects may be obtained with respect to head protection for bicyclists.
TL;DR: In this article, the authors present an approach to a high accuracy estimation technique development, taking an example of temperature control characteristics, which is an important item in evaluation of air-conditioning performance.
Abstract: In a practical application of a simulation to automotive design and development, computation to a high accuracy is needed, together with reduction of analysis labor. This paper describes our approach to a high accuracy estimation technique development, taking an example of temperature control characteristics, which is an important item in evaluation of air-conditioning performance. Key factors in the computation, such as basic analysis of air mix behavior and heat transfer model of heat exchangers, are described.
TL;DR: In this paper, the bearing wear increased at the edges of the bearing length and the crack was also observed near the edges, and the correlations between bearing damage and bearing performance were investigated.
Abstract: Recent engine bearings have been operating under harsh conditions. Consequently, wear propagates for a short time and fatigue sometimes occurs on the bearings. On the rig test machine, the operating conditions of engine bearing were simulated to reproduce the bearing damage. The bearing wear was measured until a fatigue crack occurred. The bearing wear increased at the edges of the bearing length and the crack was also observed near the edges. The experimental results were compared to the calculated results based on the elastohydrodynamic lubrication (EHL) theory. The correlations between the bearing damage and bearing performance by theoretical analysis were investigated.
TL;DR: In this article, a new aluminum alloy bearing, which reaches new levels in fatigue and corrosion resistance, was developed by improving the tensile strength of the aluminum alloy and described the performance of this new bearing material.
Abstract: In today's market, small-sized diesel engines used for passenger cars, RVs and commercial use vehicles are being pushed to new limits in fuel consumption, output and durability. As a result of these demands, engine bearings are used under increasingly severe loads and temperatures. A problem with the conventional aluminum alloy bearings which are used in these conditions is their low fatigue resistance. For this reason, a new aluminum alloy bearing, which reaches new levels in fatigue and corrosion resistance, was developed by improving the tensile strength of the aluminum alloy. This paper describes the performance of this new bearing material.