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In a state-of-the-art lean-burn spark ignition engine, a strong in-cylinder flow field with enhanced turbulence intensity is formed, and understanding the wall heat transfer mechanism of such a complex flow is required. The flow velocity and temperature profiles inside the wall boundary layer are strongly related to the heat transfer mechanism. In this study, two-dimensional three-component (2D3C) velocity distribution near the piston top surface was measured during the compression stroke in a strong tumble flow using a rapid compression and expansion machine (RCEM) and a stereoscopic micro-PIV system. The bore, stroke, compression ratio, and compression time were 75 mm, 128 mm, 15, and 30 ms (equivalent to 1000 rpm), respectively.

In order to investigate the mechanism of heat transfer on the chamber wall of direct-injection diesel engines, 2-D temperature imaging and heat flux measurement in the flame impinging region on the chamber wall were conducted using laser-induced phosphorescence technique. The temperature of the chamber wall surface was measured by the calibrated intensity variation of the 355nm-excited laser-induced phosphorescence from an electrophoretically deposited thin layer of La2O2S:Eu phosphor on a quartz glass plate placed in a rapid compression and expansion machine (RCEM). Instantaneous 2-D images of wall temperature at different timings after start of injection and time-resolved (10kHz) heat flux near the flame impinging region were obtained for combusting and non-combusting diesel sprays with impinging distance of 23.4mm at different injection pressures (80 and 120MPa).

In this study, the combustion characteristics of diesel flame achieved in a rapid compression and expansion machine (RCEM) at various patterns of oxygen distribution in the chamber are investigated in order to clarify the effect of heterogeneity of oxygen distribution in diesel engines induced by EGR on the soot and NOx emissions. To make the heterogeneous distribution of oxygen in a combustion chamber, the mixtures with different oxygen concentrations are injected through the each different port located on the cylinder wall. Results indicate that the amount of oxygen entrained into the spray upstream the luminous flame region affects the NO emission from diesel flame strongly.

Real-time analysis of benzene in automobile exhaust gas was performed using the Jet-REMPI (supersonic jet / resonance enhanced multi-photon ionization) method. Real-time benzene concentration of two diesel trucks and one gasoline vehicle driving in Japanese driving modes were observed under ppm level at 1 s intervals. As a result, it became obvious that there were many differences in their emission tendencies, because of their car types, driving conditions, and catalyst conditions. In two diesel vehicle, benzene emission tendencies were opposite. And, in a gasoline vehicle, emission pattern were different between hot and cold conditions due to the catalyst conditions.

The relation between the characteristics of a non-evaporating spray and those of a corresponding frame achieved in a rapid compression machine was investigated experimentally. The fuel injection pressure was changed in a range of 55 to 260 MPa and the other injection parameters such as orifice diameter and injection duration were changed systematically. The characteristics of the non-evaporating spray such as the Sauter mean diameter and the mean excess air ratio of the spray were measured by an image analysis technique. The time required for a pressure rise due to combustion was taken as an index to characterize the flame. It was concluded that the mean excess air ratio of a spray is the major factor which controls the burning rate and that the high injection pressure is effective in shortening the combustion duration and reducing soot formation.

In order to investigate the combustion phenomena in a combustion chamber of the diesel engine at transient operations, the simultaneous measurements of temperatures of flame and wall surface in a combustion chamber were conducted. The new technique for simultaneous measurements of flame temperature and wall surface was developed. Laser-Induced phosphorescence was used for the measurement of wall surface temperature which was coupled with the flame temperature measurement by a two-color pyrometry. The NOx and soot emissions were also measured simultaneously in transient operations. The relation between the temporal changes of emissions and temperatures of flame and surface wall are discussed. The results show that the temporal change of NOx emission during transient operation is similar to that of the average gas temperature in a chamber. On the other hand, the temporal change of soot emission is similar to neither that of flame temperature nor that of average gas temperature.

State-space solutions of H∞ controller have been well developed. Hence to a real structure control design, the first step is to get a state space model of the structure. There are analytical and experimental dynamic modeling methods. As we know, it is hard to obtain an accurate model for a flexible and complex structure by FEM(Finite Element Method). Then the experimental modeling methods are used. In this paper, we use frequency domain modal analysis technique based on system FRF(Frequency Response Function) data and ERA(Eigensystem Realization Algorithm) time domain method based on system impulse response data to establish state-space model in order to design H∞ control law for the purpose of vibration suppression. The robust control implementation is exerted on a testbed (truck cab model device) with three degrees of freedom. The validity of experimental state-space modeling is testified and the obvious vibration control performances are achieved.

To understand further the mixing process between the injected fuel and air in the combustion chamber of a diesel engine, the turbulent mixing process in a one-phase, two-dimensional transient jet was theoretically studied using the discrete vortex simulation. First, the simulation model was evaluated by comparisons between calculated and experimental data on two-dimensional turbulent jets. Second, the trajectories of the injected fluid elements marked with different colors were graphically demonstrated. Also the process of entrainment of the surrounding fluid into the jet was visually presented using colored tracers.

Local heat flux from the flame to the combustion chamber wall, q̇, was measured the wall surfaces of a rapid compression-expansion machine which can simulate diesel combustion. Temperature of the flame zone, T1, was calculated by a thermodynamic two-zone model using measured values of cylinder pressure and flame volume. A local heat transfer coefficient was proposed which is defined as q̇/(T1-Tw). Experiments showed that the local heat transfer coefficient depends slightly on the temperature difference, T1-Tw, but depends significantly on the velocity of the flame which contacts the wall surface.

Air-entrainment characteristics of non-evaporating sprays and flames were measured by means of high-speed photography including ordinary shadowgraphy of sprays, back diffused light illumination photography and laser shadow photography of flames. Effects of injection pressure and nozzle orifice diameter on air-entrainment characteristics were investigated parametrically. The amount of air entrained into a flame was calculated by a two-zone thermodynamic model with data obtained from the photographs and the pressure measurement in the combustion chamber. The air-entrainment characteristics of flames were compared with those of the corresponding sprays. It showed that immediately after the start of ignition, the air entrainment into a flame increased more rapidly as compared with the corresponding spray and then, with the development of diffusion combustion, the air entrainment gradually approached that of the spray.

A new method to determine simultaneously the temperature and the fuel vapor concentration inside an evaporating spray was described by using a laser-induced fluorescence technique. A TMPD doped base fuel composed of C12H26: 22%, C13H28: 54% and C14H30: 30% was injected into the combustion chamber of a rapid compression machine which is filled with a high temperature and high pressure nitrogen. The laser sheet was used for incident light, which was reflected by a prism located inside the combustion chamber and propagated through the center of an evaporating spray. The laser induced fluorescence intensity was imaged by a high speed-gated intensifier from a direction perpendicular to the incident light. The results shows that mixtures with high equivalence ratio are observed in the central region, while low equivalence ratio mixtures are observed in the periphery of the spray. It is also observed that the temperature of richest mixture is 50 K as low as the surrounding gas temperature.

Robust performance control of an autocruise system for a heavy-duty truck is described. The controller design is carried out employing a loopshaping method, considering dynamics variation caused by the gear shift, the load changes, the vehicle speed and also the vibrational characteristics of the propulsion system as the plant uncertainty. Thereby a robust-stable controller is obtained without sacrificing the response to disturbances. Finally, nonlinear simulations and real vehicle experiments prove that the steady-state performance and its robustness excel the conventional PID's.

A rapid compression-expansion machine was developed, which can simulate intake, compression, expansion and exhaust strokes in a single Diesel cycle by an electrically controlled and hydraulically actuated driving system. The whole system which is composed of a hydraulic actuator, fuel injector and a valve driving device, is sequentially controlled by a micro-computer. The machine features; 1) accurate control of piston position at TDC, 2) no effect of lubricant on HC emission due to the use of dry piston rings; 3) independent control of local wall temperature; and 4) high power output to drive heavy piston at high frequency. The single cycle operation permits Diesel combustion experiments under a wide range of operating conditions and easy access of optical diagnostics with minimized amount of test fuel. The performance test showed that the machine can drive a DI Diesel type piston with a 100 mm bore at a maximum frequency of 16.7 Hz at a maximum compression pressure of 15 MPa.

In an attempt to achieve lean combustion in Diesel engines which has a potential for simultaneous reduction in no and soot, the authors developed a micro-hole nozzle which has orifices with a diameter as small as 0.06 mm. Combustion tests were carried out using a rapid compression-expansion machine which has a DI Diesel type combustion chamber equipped with the micro-hole nozzle. A comparison with the result of a conventional nozzle experiment revealed that the ignition delay was shortened by 30 %, and in spite of that, both peaks of initial premixed combustion and diffusion combustion increased significantly. The combustion in the case of the micro-hole nozzle experiment was accompanied with a decrease in soot emission, whereas an increase in NO emission.

The local heat fluxes from impinging combusting and evaporating diesel sprays to the wall of a square combustion chamber were measured in a rapid compression machine. It was revealed that the ratio of local heat flux between the combusting and evaporating spray, q̇c/q̇e, is of the same order of magnitude as (Tc-Tw)/(Te-Tw) and its values estimated by a two-zone model agree roughly with the measured ones. The time-mean local heat flux during the spray impingement was found to be approximately proportional to the 0.8th power of the injection velocity and the heat-transfer phenomenon depends largely on whether the ignition starts before or after the impingement.

A one-dimensional numerical calculation has been performed on a new reciprocating heat engine proposed on the basis of super-adiabatic combustion in porous media. The system consists of two pistons and a thin porous medium in a cylinder; one being a displacer piston and the other a power piston. These create reciprocating motions with a phase relation angle. By means of the reciprocating flow system, the residual combustion gas enthalpy is effectively regenerated to induce enthalpy increase in the mixture through the porous medium. Due to heat recirculation, the thermal efficiency reaches to 58% under the condition of the compression ratio of 2.3.

Wet multiple plate clutches consist of friction plates, on which a friction material is bonded, and mating plates that are plain metal plates. Since the frequency and the range of load in the field of forklift trucks vary widely and are more severe than those for passenger cars, the wet multiple plate clutches on forklift trucks are often damaged. Damaged clutches that were returned from the field typically had 3 types of symptoms: 1.Only the friction material was damaged, 2.Only the mating plates were deformed, 3.Both symptoms were observed. It was clear that the cause of these symptoms depended on the difference of the operating application and the strength criteria of each part. This showed that a design guide for wet multiple plate clutches considering the strength balance between the two parts according to the work application was required. The relevant flow chart of this design process was proposed.

A diesel spray and flame in a quiescent atmosphere were realized without interference with combustion chamber walls in a newly constructed rapid compression machine. High speed shadow photography and pressure measurement were employed to obtain data for calculating the amount of air entrainment into the the flame and spray. From a comparison of air entrainment between the flame and spray, it turned out that when ignition delay becomes longer air entrainment into flames is promoted by the thermal expansion of multi-points ignition sources in the central region of the spray.

The concentrations of soot, NO and the other combustion products were measured by incylinder gas sampling in a DI diesel engine. The effects of injection timing, swirl ratio, and combustion chamber geometry on the formation and emission processes of soot and NO were studied. The following results were obtained: (1) Soot is promptly formed in the flame during the early combustion period where the equivalence ratio in the flame is high over 1.0. Thereafter almost all the formed soot is swiftly burnd up by oxidation during the middle combustion period. This process mainly determines the exhaust soot concentration. (2) NO is formed in the flame during the early and middle combustion period where the flame temperature is high over 2000 K. The highest NO concentration is observed at the flame tip swept by the air swirl. Though the concentration of the formed NO decreases by dilusion it nearly constant during the later combustion period.

A rapid compression-expansion machine which can simulate the combustion processes in diesel engines is developed. The configuration of the combustion chamber is a 100 mm bore and a 90 mm stroke, and the compression ratio is 15. The piston is driven by an electro-hydraulic system with a thrust of 90 kN and the maximum frequency of 20 Hz. The whole system composed of a hydraulic actuator, a fuel injection system, and a valve driving unit is sequentially controlled by a computer. The reproducibility of the stop position of the piston at the end of compression is achieved with an accuracy of ±0.1 mm by employing a hydraulic-mechanical brake mechanism. The experiment shows that the combustion in the expansion stroke is achieved, and that the combustion characteristics such as the rate of heat release and indicated output as well as the exhaust emission can be measured.