We tried modeling of ammonia slip catalyst (ASC) for the purpose of model-based development of Urea-SCR system which is NOx purification device for diesel exhaust gas. In this report, we introduce the ammonia oxidation model on the PGM catalysts and the parameter identification method with genetic algorithm. The developed ammonia oxidation model can predict the influence of SV and PGM loading amount with high accuracy and is therefore expected to be useful as a kinetic model of PGM catalyst for the Dual layer (SCR+PGM)ASC.
Exhaust emissions and combustion stability of diesel engines can be improved by feedback control using a cylinder pressure sensor (CPS). However output of the CPS can deteriorate due to deposits on the sensor. To address this issue, an on-board model was developed to compensate CPS output based on the spring-mass-damper model. Young's modulus of the deposit causes a variation of the spring constant and resulting degradation of the signal level. Deposit porosity leads to a variation of the damper constant and resulting signal delay. The proposed model based on the analysis can estimate the cylinder pressure with the required accuracy for the feedback control.
In penetration phase of automated vehicle into market, adapting automated vehicle control to the driver’s individual driving style is assumed to contribute to feeling of safety and acceptability. In this study, we proposed and demonstrated a modeling method with a small number of parameters to adapt distance to preceding vehicle during automated vehicle control to the driver’s individual driving style. An experiment using a real vehicle on a proving ground showed the effectiveness of our method to increase the driver's feeling of safety and acceptability.
This study models short circuits of spark channels and discharge blow-outs. In the short circuit model, spark channels are short-circuited between two arbitrary locations when the electric potential difference between the two locations exceeds a certain threshold. The threshold is varied as a function of distance between the two locations as well as the discharge current. In the discharge blow-out model, discharge blows out when discharge current fall below a certain threshold, which increases with spark channel length. Furthermore, this study suggests modifying the Kim et al.’s equation which predicts electrical resistance of spark channels.
The submodels of spark channel short circuit and blow-out, which were described in the 1st report, were implemented into a spark ignition model. The short circuit, whose major factor is electric potential differences between two arbitrary locations, occurs in the early phase of the discharge period and the blow-out, whose major factor is discharge current, occurs in the latter phase of the discharge period respectively. The behavior of spark channel, current and voltage of the secondary circuit and the ignition limit by increase of EGR rate agreed with a measurement data of a spark ignition process in a chamber.
Takeshi Mori, Masafumi Sakota, Koji Nemoto, Takahiro Kogawa, Yoshinobu Kakizaki
Diesel Particulate Filter (DPF) regeneration requires high exhaust gas temperature by post -injections, which causes issues of fuel penalty and emissions. Therefore, it is desirable to shorten the DPF regeneration period. Ag catalysts by conventional coating method can’t exhibit their capabilities expected, due to their poor contact between PM and catalysts. To improve PM-catalysts contact condition, a new coating method which enables to achieve “tight contact” between PM and catalysts was developed. Abnormal temperature rising characteristic accompanying improvement in PM combustion performance was able to coexist by adjusting coat length in DPF. This method enables to promote DPF regeneration, making improve fuel economy and emissions.
In the present study, unsteady vehicle aerodynamics caused not by a periodic condition but by an intermittent disturbance has been investigated, especially focusing on the aerodynamic drag. Aerodynamics of simplified vehicle models, which had different geometry only in the rear-end corner, were measured in a wind tunnel with a transition of aerodynamic yaw angle. From the measurement results, relationship between unsteady aerodynamics and aerodynamic phenomena has been investigated. A model with the rounded corner shape showed hysteresis on the aerodynamic force. Transitional phenomenon of flow separation on the rear-end corner was considered as a cause of the hysteresis.
A total of eighty-one side collision simulations were conducted with four THUMS Version 4 adult female occupant models seated. The collision conditions were determined based on actual vehicle side collisions. Occupant kinematics and head injury were predicted and compared. The simulation results indicated that serious head injury (AIS3+) was likely to occur when the far side occupant head contacted the near side occupant. It was also shown that the kinematics of the far side occupant was different from that of the near side occupant.
When driving on uneven road, the road input causes a vehicle various motions. Although the studies on bounce and pitch responses to road input in the view point of ride comfort have been reported, there are not a lot of analyses of lateral, yaw and roll responses on uneven road. In this paper, these responses to road input during turning was focused. A hypothesis about the phenomenon were formulated and were verified.
Vehicle localization based on matching between on-vehicle camera images and high-precision map has been developed for automated driving. We propose a method to associate a map with images by stochastically generating a white line section corresponding to appearance from white line types. Moreover, we propose a robust method by estimating not only the latest location but also the trajectory of the vehicle. The proposed method was tested in Shuto expressway, and the vehicle position was identified with sub-meter accuracy.
We propose a new cylinder head gasket model for the precise prediction of cylinder deformation. The proposed model is based on the high-order deformation modes of cylinder head gasket with the material characteristics of rubber coating and metal plate. This improvement affects the shear behavior of the contact surface between cylinder head gasket and cylinder block. According to the comparison with experiment results, it is found that the proposed model increases the prediction accuracy of the frictional shear force and contact status of cylinder head gasket without matching parameters for experiment conditions. The proposed model provides a useful design method for cylinder head gasket and engine structure.
In this study, we calculated cylinder deformation under high pressure condition. Proposed model treated contact interaction between a head gasket and a cylinder block deck surface or a cylinder head considering frictional and shear behavior of the cylinder head gasket. The model was able to predict the changing margin of the deformation by different gasket structure type. According to the results, we found that transient phenomenon was occurred by changing contact interaction state from stick condition to slip condition regarding cylinder deformation toward cylinder pressure. Besides, we found that head gasket shear stiffness and frictional coefficient affected cylinder bore deformation.