To improve the cooling system of internal combustion engines, the utilization of the nucleate boiling heat transfer is desired. Our previous study revealed the relationship between the water nucleate boiling heat flux and dimensionless numbers. By using 50% ethylene glycol aqueous solution (EG50%) as coolant, the nucleate boiling heat flux was measured on the corroded heating surface and compared with the experimental data of water as coolant. Subsequently, dimensional analyses were done to investigate the necessary dimensionless numbers affecting the forced flow nucleate boiling. Two new models are proposed for water and EG50% as coolants, and predicted heat flux results were found to be in an average error of 9.7% and 10.1%, respectively.
This paper presents a study to quantify the difference in roll feel experienced by the driver with a change in damper characteristics between “comfort” and “sport” mode. The vehicle and driver’s motion are measured during the double lane change maneuver. In “sport” mode, the timing of steering operation was found to be faster (P = 0.0456), which can be explained by the driver being able to make quick upper body corrections to resist the slow vehicle roll motion. This difference in steering operation because of the man-machine feedback system can be considered as an objective measure to quantify roll feel.
Recently the traffic accidents fatality is reducing, but still the fatality of vehicle occupants is large part of them. Vehicle occupants are protected with seatbelt and airbag in frontal crashes and the large effects of them are reported by many researchers, but the report about the side airbag effect was not plentiful, because there was insufficient side impact accident data with new protection device Now almost all cars equipped side airbags and rollover air curtains, and more accident data with side airbags becomes available. The author analyzed US NASS CDS data to investigate the effect of side airbags and head protection rollover air curtains in nearside impact. Results shows the most frequent injury is to the torso regardless of whether the side air bag deployed or not. More study is needed about the effect of rollover air curtain for head/neck injury, and torso air bag has some effect, but it is not the level of seatbelt in frontal crash.
In previous paper, evaluation model for four-wheeled vehicle accident risk in hilly and mountainous area was considered using sideslip limitation speed by 3D measurement for road alignment. This paper aimed to improve the risk evaluation model by considering the risk for curve misrecognition, and verified using real accident locations. The distance where driver can recognize the forward curve from its starting point is shorter at the sharp curve compared to the loose curve. The curve misrecognition risk is considered to be the delay of the reducing vehicle speed before the curve. The points of road at the defined accident risk level of 0.75 and more are considered as dangerous location, and a lot of accidents occurred at the point by lane departure. Moreover, hazard map for traffic accident in hilly and mountainous roads was constructed using the accident risk evaluation model.
Compact and low-cost devices are needed for autonomous driving to image and measure distances to objects 360-degree around. We have been developing an omnidirectional stereo camera exploiting two hyperbolic mirrors and a single set of a lens and sensor, which makes this camera compact and cost efficient. We establish a new calibration method for this camera considering higher-order radial distortion, detailed tangential distortion, an image sensor tilt, and a lens-mirror offset. Our method reduces the calibration error by 6.0 and 4.3 times for the upper- and lower-view images, respectively. The random error of the distance measurement is 4.9% and the systematic error is 5.7% up to objects 14 meters apart, which is improved almost nine times compared to the conventional method. The remaining distance errors is due to a degraded optical resolution of the prototype, which we plan to make further improvements as future work.