Two examples of invention using TRIZ method by students at the Kanagawa Institute of Technology (KAIT) in project based learning are reported. One is an engine intake system design that solves trade-offs between maximizing engine performances and minimizing space the system occupies. The other is a front suspension system that enables a newly developed walking aid to over-ride high gaps with small thrust force while giving it stability and shock absorbing function. In both cases, students' skill of using computer aided engineering (CAE) software and their manufacturing experience played an important role in university level engineering design education.

View full abstract

To reduce the aerodynamic tonal-noise from rearview mirrors, active flow control techniques were utilized with oscillating jets on the surface of rear-view mirror. The experimental results showed the noise reduction level depended on the frequency and intensity of the oscillating jets. The noise reduction level was 20 dB at the oscillation frequency about 400Hz and the jet velocity about 0.1 m/s. Both of the frequency and intensity of the jet were smaller than the frequency of the feedback noise and the uniform flow velocity. These results indicated that the oscillating jets effectively reduced aerodynamic noise with small amount of energy.

View full abstract

A shock absorber damps vibration and generally converts the energy to heat. With an electromagnetic suspension which has an electric motor, the vibration energy can be converted into the electric energy. Because the amount of the absorbed energy depends on the damping of the suspension system, the damping control by the active suspension makes the energy saving control possible. In order to clarify the relationship between the velocity feedback gain and the energy consumption, the numerical simulation and experiment with an actual electromagnetic damper were operated. The experimental results demonstrated that the electromagnetic suspension system can improve the properties of the sprung mass without consuming energy.

View full abstract

Influence of upper-rear body configuration on aerodynamic characteristics of a passenger vehicle has been experimentally studied. By rounding the upper-rear body, the recirculating region of the wake behind the passenger vehicle was narrowed, while the streamwise vortices at both sides were expanded. The drag force and lift force were therefore increased. The experimental results show that the rear configuration can modify the wake structure behind the passenger vehicle. As the aerodynamic force is related strongly with the wake structure, it is said that the total aerodynamic characteristics might be controlled by modifying the rear configuration of the passenger vehicle.

View full abstract

Some approaches to understanding driver and vehicle dynamic characteristics using jerk information are studied in this paper. Observing the driver's each maneuvers through all the process from braking and turn to cornering state and accelerating to go out the corner, the durations of combination of longitudinal and lateral acceleration were specified, and the generation periods of yaw moment caused by tire vertical load shift also were specified by the jerk information. The periods are rational from the vehicle dynamics point of view, and we confirmed the drivers did "Yaw moment control by tire vertical load shifts". An experimental understanding and theoretical study are discussed.

View full abstract

Some approaches to emulating expert driver's longitudinal and lateral integrated control using jerk information are studied in this paper. We proposed a longitudinal driver model which works in coordination with any steering input. The longitudinal acceleration command is calculated by the vehicle lateral jerk information. Adopting programmed and preview-follower model for the steering input, we compared with the expert drivers cornering and braking lane change test results. The both results agree well, and we confirmed the model can emulate a certain respect of expert driver's control strategy for trade-off between longitudinal and lateral acceleration.

View full abstract

Existing steering control method is attributed to the mechanism developed in the 18th century and since then people have been compelled to adapt its rather awkward control rule. However, at the break of Steer-By-Wire era, it is considered to be meaningful for us to search for better control rules other than the existing. In this report, in order to develop more driver-friendly and higher-performance control rules, open loop steady state and dynamic response characteristics of several basic steering control rules ever proposed and clue to promising candidate are discussed from the unique standpoints with newly contrived means.

View full abstract

Existing steering control method is attributed to the mechanism developed in the 18th century and since then people have been compelled to adapt its rather awkward control rule. However, at the break of Steer-By-Wire era, it is considered to be meaningful for us to search for better control rules other than the existing. In this second report, steady state and dynamic response characteristics as well as safety and handling related performance of one promising control rule found through the search presented in the first report are multilaterally reported.

View full abstract

In this paper, impact energy absorption capacity for thin-walled tapered tube subjected to axial compression is studied by using a finite element method MSC.Marc. In particular, effects of tube geometries on the deformed shapes and variations of compressive load are discussed. Thin-walled tapered tube has an advantage over a non-tapered tube, because its compressive load can be enhanced and its energy absorption capacity increases during axial compression. Moreover, based on our numerical result, we propose an evaluation technique in order to predict the compressive load and deformation diagram for the tube. This prediction gives good agreement with our experimental result.

View full abstract

Since the stable operating region of a gasoline-fueled HCCI engine is limited to the part load condition, a mode change between SI and HCCI combustion is required, which poses an issue due to the difference in combustion characteristics. This report focuses on the combustion characteristics in the transitional range. The combustion mode in the transitional range is investigated by varying the internal EGR rate, intake air pressure, and spark advance timing in steady-state experiments. In this parametric study, stable SI-CI combustion is observed. This indicates that the combustion mode transition is possible without misfiring or knocking, regardless of the variable valve mechanism.

View full abstract

Laser ionization/time-of-flight mass spectrometry is extremely expected to be a sensitive technique in the continuous analysis. However, this method was used for the basic research in the laboratory, due to using a complex tunable laser. In this work, we investigated the optimum conditions of sample introduction and laser irradiation method to use a practical measurement. As a result, 3-ppb naphthalene was detected using a high-temperature short-pulsed valve and non-resonant ionization method. Moreover, we checked the sensitivity for a number of standard sample of PAH and finally applied this modified device to analyze exhaust gas of a practical diesel engine.

View full abstract

Using small thin-film pressure sensors deposited onto a piston skirt surface, oil-film pressure on the piston skirt surface is measured when piston slap noise is generated without affecting the surface geometry, stiffness and mass of the piston. Under a no-load firing engine condition and at low temperature, the measured oil-film pressure corresponded well to the measured acceleration of the cylinder liner, which is indicative of piston slap noise, confirming the validity of the present method. And this resulted in more insight into piston secondary motion than only by acceleration of cylinder liner when the piston collides with the cylinder liner.

View full abstract

The VVEL system has the valve lift characteristics unique to a multiple-link mechanism. It provides large valve lift in the high-speed range combined with low friction at low engine speeds. This paper describes the structural features of the multiple-link valve mechanism that achieve such characteristics as well as the various performance levels attained with the VVEL system.

View full abstract

In order to know a stress distribution in piston-pin boss in engine operating condition, a new thin-film sensor was developed to measure the oil-film pressure in pin-bosses. The sensor which has φ0.45mm sensing part and 7μm in total thickness was deposited by sputtering on a piston pin surface. This kind of sensors succeeded already in measuring oil-film pressure distribution in engine bearing. However, the result was affected by high temperature in piston pin, especially by temperature dependence of sensor sensitivity. For obtaining the stable characteristics, nitride layers were applied as protection and insulation layers. This paper presents the new structure of sensors and measurement results.

View full abstract

The authors have developed a new measuring method of the liquid film thickness on a wall using laser-induced fluorescence. With this method, temporal variations of fuel film are obtained. Using this method and high-speed video camera, behaviors of fuel film formed by impinging fuel spray against the wall were observed. Effects of injection quantity, distance against the wall, impinging angle and wall temperature on the film behaviors were also investigated. Fuel film was thicker at the tip of the film. This tendency declined as impinging distance increased. Wall temperature had low impact during spray hitting.

View full abstract

Multi-hole spray interference and mixture formation play an important role in ignition and combustion process in diesel combustion. The experiment uses a rapid compression machine with applied a reflex schlieren photography method to investigate fuel-air mixing process during ignition delay period. Hole-diameter, hole-number and swirl velocity are changed as experimental parameters. Schlieren images reveal spray interaction and evaporation process clearly. The schlieren images are analyzed by comparing with flame images and combustion pressure diagrams. Results show the effects of mixture formation process during ignition delay period on ignition and combustion of diesel sprays.

View full abstract

The effect of high pressure loop (HPL-) and low pressure loop (LPL-) EGR systems on engine performance and emission characteristics were investigated using a multi-cylinder diesel engine under steady-state conditions. The HPL-EGR achieves higher fuel economy at low load while the LPL-EGR can sufficiently lower intake gas temperature and can reduce NOx and soot emissions. Especially at high load, LPL-EGR can reduce NOx and soot emissions without fuel penalty. At low load, on the other hand, the LPL-EGR can reduce NOx to meet the post new long-term regulation target without increasing soot emission than HPL-EGR baseline.

View full abstract

The effect of GTL (Gas to Liquids) fuel on emission characteristics under steady-state conditions was studied using a 4-cylinder diesel engine. Soot, CO and THC of the GTL fuel were lower than those of diesel fuel. Then, emission improvement was tried with increasing a high pressure loop (HPL)-EGR rate. A low pressure loop (LPL)-EGR was also introduced to improve further emissions. Both EGR systems could take advantages of GTL fuel characteristics and had possibility of reducing NOx with keeping the same soot level as Diesel fuel. The LPL-EGR was effective at middle to high load, while HPL-EGR was effective at low load with less penalty of BSEC.

View full abstract

To further understand the characteristics of smokeless low temperature diesel combustion, the effect of fuel cetane number on mixture formation and combustion characteristics of a single cylinder DI diesel engine was investigated using the engine experiments and CFD code. The results show that besides combustion temperature, fuel-air mixing is also vital to efficient smokeless and low NOx diesel combustion. Smokeless low NOx diesel combustion can be realized even with insufficient fuel-air mixing as long as the combustion temperature is sufficiently low. However lower temperature combustion causes very high THC and CO emissions, and severe deterioration in the combustion efficiency. When the ignition occurs later than about 4 °CA after the end of fuel injection, there is smokeless combustion regardless of fuel cetane number and injection timing and NOx is suppressed to near zero levels by large quantities of cooled EGR. Finally, the operating range of smokeless and ultra-low NOx diesel combustion with low compression ratio and low cetane number fuels are discussed.

View full abstract

In order to reduce exhaust emissions and increase the brake thermal efficiency in a direct injection (DI) diesel engine, we pursued the multi-stage fuel injection characteristics and combustion chamber under the common rail fuel injection system and high compression ratio. As a result, the following conclusions were obtained. (1) The high compression ratio combustion was effective to improve exhaust emissions and the break thermal efficiency. (2) The relations between the combustion chamber and gas flow characteristics, the fuel injection characteristics and combustion characteristics were clarified. (3) For the high compression ratio combustion, the after injection was effective to reduce smoke emission.

View full abstract

Effects of high-injection-pressure up to 240MPa and injection-rate-shaping on rating power and its revolution, and on exhaust emissions from an HSDI diesel were investigated using single-cylinder research engine. Fuel-air equivalent ratio (φ) limited by exhaust smoke number is strongly associated with velocity ratio of fuel-spray to squish air motion. It is confirmed high injection pressure of 240MPa realizes equivalence ratio of φ0.78 at 5000rpm. Effect of initial injection-rate-suppression on exhaust emission decreases as charging efficiency is increased. High injection pressure over 200MPa is also effective on reduction of NOx and Smoke with combination of high-boost pressure and high EGR-ratio.

View full abstract

The group-hole nozzle has a series of groups of holes and each group consists of two small holes with a small spatial interval and a small angle. It is expected that the spray behavior of the group-hole nozzle has enough spray tip penetration and smaller mean droplet diameter as compared with the spray injected by the conventional multi hole nozzle having the hole area same as the group-hole nozzle. To investigate effects of the group-hole nozzle on the mixture characteristics, the extended ultraviolet and visible Laser Absorption Scattering (LAS) technique, which can be applied to a non-axisymmetric spray, was developed. Liquid and vapor phase mass distributions in the spray were obtained by the extended LAS technique. The analyses were made of the free sprays and the flat wall impinging sprays. In the case of the free sprays, the group-hole nozzle with the larger spatial interval of two holes enhances fuel evaporation though decreases the spray tip penetration. In the case of the impinging sprays, the group-hole nozzle enhances the fuel evaporation as well as the spray tip penetration.

View full abstract

The objective of this research is to characterize the performance degradation attributable to the shutdown operations of polymer electrolyte fuel cells and to explore possible methods of reducing such degradation. As a result, it was made clear that a sequence of shutting off the air supply prior to stopping the hydrogen supply was effective in mitigating such performance degradation. Diagnostic technology revealed that the performance degradation was mainly observed at the cathode catalyst and that it was caused by so-called reversal current, which was triggered by air that crossed leak from the cathode to the anode.

View full abstract

The Combustion mode switching from SI to HCCI combustion is essential for practical use of the HCCI engine, especially, in the case of HCCI with internal EGR. The combustion mode switching was examined by cam profile switching from the valve overlap cam profile to the negative valve overlap cam profile. Finally, the combustion mode switching from SI to HCCI was demonstrated by switching the cam profile without any misfires and with an acceptable combustion noise level by controlling the throttle valve, fuel control valve, and exhaust valve closed timing, intake valve opening timing.

View full abstract

In order to control the natural-gas PCCI combustion, the internal EGR by means of exhaust valve re-opening(EVRO) during induction stroke was applied to a single-cylinder test engine. Combustion phasing can be controlled successfully by adjusting the EGR ratio, so that improvement of thermal efficiency and the reductio in unburned exhaust-emissions can be achieved. Also, results of EVRO method have been compared to those of inteke-valve pilot-openig (IVPO) during exhaust stroke. It is shown that EVRO is more useful heat-recovery metod for PCCI combustion improvement than IVPO.

View full abstract

The aim of this study is to investigate the deposition remains of fuel droplets that impinge repeatedly on a hot surface. The fuel droplets tested are diesel fuel, bio-diesel fuel and bio-blended diesel fuel. The deposits formation depended on droplet impingement interval, hot surface temperature, types of fuel and heat transfer of fuel deposits. Bio-diesel fuel and its blend produced rapid development of fuel deposits comparing to diesel fuel. The surface temperature of deposits decreased with repetition of impingement when the wet condition was maintained by a short impingement interval. It resulted in a huge amount of deposits.

View full abstract

GTL fuels have many advantages as an alternative cleaner diesel fuel. Higher Cetane number and the absence of Poly-Aromatic Hydrocarbon content, which are the principal properties of GTL fuels, have a potential to reduce HC and PM emissions. Further the absence of sulfur content will result not only in the PM emission reduction, but also in the deterioration restraint of aftertreatment catalyst activities. In this study, the effects of GTL fuels on combustion and emissions characteristics of the latest diesel engines were evaluated. In addition to these tests, a single-cylinder engine with optical access was used for the combustion analysis.

View full abstract

Newly developed high performance EDLCs are in the midst of the growing expansion of applications to HEVs and other power systems. However, the lack of optimal performance measurement methods corresponding to increasingly complicated characteristics of new EDLCs prevents easy application engineering. Therefore, following the 1st report, various experimental and theoretical analysis for new high performance EDLCs were performed. As a result, optimal testing methods for measurement and evaluation of new EDLCs were successfully established to reveal their capacitance, available energy capacity, internal resistance, charge/discharge efficiency, etc.

View full abstract

We researched feature factors of sleepiness expression to do observational analysis about some driver's facial images during a monotonous driving task. It was found that not only eyes condition" which was generally investigated but also "cheeks and oris relaxation" "eyebrows raising", "head slant" and "oris movement" were selected as the factors.

View full abstract

We propose a newly pedestrian model for evaluating vehicle-pedestrian accidents using STREET we have been developing. The pedestrian model can simulate pedestrian-to-vehicle interactions by making pedestrians and drivers behave in their surroundings based on their cognition and decision. It reproduces the behavior of pedestrians by setting up action rules governing combinations of positions of pedestrians, their modes of action, and cognition targets. Finaly, we have validated the pedestrian mode with an example of simulating basic operations regarding the ignoring of signals and vehicle-to-pedestrian right-turning gaps, thereby comfirming that the example exhibits a tendency that closely corresponds to the actual measurements.

View full abstract

This paper tries to develop a method to detect driver's specific actions in a non-intrusive manner. The Higher-order Local Auto-Correlation (HLAC) feature is extracted from the data of a pressure distribution on the seat cushion measured with a tactile sheet, and a linear discriminant analysis is performed to classify the data. The results suggest that the method may be successfully applicable to both evaluation of driver's ''preparedness'' to depress the brake pedal and detection of driver's actions that are unnecessary for driving.

View full abstract

The purpose of this study is to investigate an influence of the brightness distribution of the road surface on recognition of an object on the road. By modeling light distribution of low beam on CRT display by a computer, we examined a visibility of the target on the brightness of background as the light distribution model. The target horizontally runs reciprocating motion, its luminance decreases step-wise and also the luminance contrast between background and target. If the target is visible, the subject can gaze the moving target, if it is invisible the subject can not gaze. We measured the luminance contrast threshold of the target by using the so-called moving target method. As the results, we found out that driver's discomfort feelings were increased and the target visibilities were reduced, on the case of the excessive road surface brightness.

View full abstract

Driver performance and situation awareness are affected by critical human factors, such as the driver's interaction with alerting schemes, and the distractions that he or she faces while driving. We conducted an experiment to study the efficacy of a single master alert versus multiple individual alerts for different Advanced Driver Assistance Systems (ADAS), and how they affect a driver's response to imminent collision situations while distracted. The ADAS warning systems included auditory alerts for imminent frontal collisions, or unintentional left/right lane departures. Regarding the master alarm versus individual alarms, our results showed that there was a significant difference in drivers' reaction times under Forward Collision Warning (FCW) conditions, but that there was no significant difference under Lane Departure Warning (LDW) conditions.

View full abstract

The vibration transfer characteristics of the body and seats are becoming more important as automakers strive to satisfy demands for improved ride quality. This study shows that the vibration of a virtual rigid body can be calculated by expressing the vibration magnitude of each part in a vehicle shaker test as the product of the suspension transmission force and inertance. Consequently this analytical method is effective for quantifying the vibration amplification rate caused by the body and other elements.

View full abstract

One of the big problems to decrease interior noise is that most methods to reduce road noise have no small negative effects on the other performances as vehicle dynamics, etc. We suggest new way to reduce road noise that uses sheets of acoustic material generally used to reduce high frequency noise. Acaustic model experiments made it clear that neccesary rrquirement for mid-frequency acoustic absorption by using the sheets of absorption material is derection of the particle velocity. The sheets of absorption material put on the flat space separated by a plate that caused to vibrate easily can absorb road noise.

View full abstract

This paper describes improvement of simulation accuracy with a shell honeycomb ODB model. It was a technical issue that simulation result with deformable barrier model wasn't sufficiently accurate for comparing barrier force history to the test. Simple compression simulations of Aluminum honeycomb were performed and it was found that hourglass control for shell elements caused the difference between the test and FE result. Another shell element formulation that didn't require hourglass control was applied to honeycomb model. ODB frontal collision simulation result with the new barrier model showed much better correlation with the test than the previous model.

View full abstract

Hardware In the Loop Simulator (HILS) method was declared in march 2007 as fuel consumption and exhaust emission test of hybrid electric heavy duty vehicles. Accelerating and breaking of HEV model with vehicle parameters is simulated by driver model of HILS system. And then JE05 driving test mode is virtually run on the HILS system. In this study, sensitivity analysis of inputting parameter to HILS parallel-HEV model was conducted in order to assess the effect of vehicle parameters on fuel consumption simulated by HILS system.

View full abstract

Merging a CAE shape optimization system and SN-ratio index of Taguchi method, a robustness-considered automated optimization method has been developed. Applying this method to diesel intake ports, mold position tolerance was considered as the error factor, SN-ratio was defined with the swirl stability. As the result of the optimization with multi objective genetic algorism, simultaneous improvement of flux, swirl rotation and SN-ratio was achieved.

View full abstract

Technical possibility ty of an engine system (combustion, exhaust aftertreatment) which made good use of a characteristic (zero sulfur, zero aroma and high cetane number) of FTD fuel was examined. The clean diesel which was much less than a current exhaust emission level by a small change of combustion / aftertreatment system could be realized in a base of a commercial 2L class small diesel engine, and this mechanism was described in detail experimentally.

View full abstract

This study changed intake valve timing for improving knocking limit on the Spark Ignited Engine fueled with mixture of DME and LPG, which has much reality in the future because of the fact that DME requires a similar supplying infrastructure for LPG. 1-D simulation tool and a knocking model were employed to intake valve timing optimization. The simulated solution was checked on the real engine and exhaust emission was measured and compared with that from previous valve timing.

View full abstract

It is important to use BDF (biomass diesel fuel)-blended diesel fuel for preventing increase in carbon dioxide emission in the world because FAME (Fatty Acid Methyl Ether) which is main component of BDF is made from biomass; e.g. palms oil and rapeseed oil, et al., and because biomass energy source has an carbon-neutral impact. FAMEs have different fuel properties about corrosion to materials, oxidation of themselves, and fluid behavior in cold environment. Especially it is not well known about the effects of FAMEs or FAME-blended diesel fuels on vehicles developed on the assumption that the gas oil should be used to the vehicles.
In this study, as FAME-blended diesel fuel was applied to a diesel vehicle, the effects of the fuel properties on startability and driving performance of the vehicle in cold environment were investigated. The experiments were conducted using a chassis dynamometer in an environment room in which the room temperature was set to -10 deg. C. The FAME used in this study consists of some kinds of FAME, and the properties of the FAME are adjusted to meet European Standard EN14214.

View full abstract

We have developed a new eye closure detection and gaze estimation method that processes a driver's facial images captured with a monocular camera in the vehicle cabin. Test results show that open/closed eyes can be detected with 90% and 70% accuracy, respectively, and that three gaze directions (front, right and left) can be detected with 80% accuracy without prior person-by-person calibration.

View full abstract

According to its powertrain strategy, BMW introduces the new 6- and 4-cylinder inline petrol engine generation, featuring a stratified DI combustion system with High Precision Injection. The spray-guided combustion system eliminates the disadvantages of the wall- and air-guided 1^st generation DI combustion systems, providing a stratified mixture at the spark plug and significantly reduced wall wetting. The piezo injector permits an extremely fast actuation, providing high flexibility for the calibration strategy to supply a very efficient combustion with low unburnt hydrocarbon and carbon monoxide emissions. The paper presents the realised potentials and technical features of this new engine generation.

View full abstract

In this paper, the traffic hazard map, which shows hazardous locations, was constructed by using sudden deceleration events collected from about 1,500 probe-cars. By comparing hazardous locations on the hazard map with actual high-accident locations, the validity of the map was verified. Also, by developing the system that informs a driver on hazardous locations on the basis of the hazard map, the effect of the information provision was examined.

View full abstract

We proposed the some types of guidance system with communications. In this study, we have proposed some kinds of comprehensive human machine interface (HMI) from the guidance system to a driver for indication of vehicle control and done the experimental study for evaluating it. Firstly, the three ways of indication as HMI with W-LAN were proposed and evaluated by experiments. By considering the test results, another way of indication as new HMI with a car stereo was proposed and was evaluated by experimental results. As the results, the vehicle could be guided to the parking place by using the proposed way

View full abstract

In Japan, it has been mandatory since March 2005 to equip the driver's seat of passenger cars with the safety belt reminder system (SBR). To confirm the effect of SBR, the following two items have been conducted in this survey.
(1) Survey on the ratio of safety belt use with/without SBR: It was confirmed that SBR is very effective to increase the driver's safety belt use (from 90.1% without SBR to 97.3% with SBR).
(2) Interview to users of SBR-equipped passenger cars: How and when SBR is activated were clarified, positive and negative evaluations of SBR functions were collected.

View full abstract