混合动力客车油门踏板安全对策

针对混合动力客车油门踏板使用中的失效问题,通过分析油门踏板、整车控制器(HCU)原理、整车控制策略,修改HCU油门踏板策略后,有效地解决了油门踏板失效的故障诊断和安全处理问题。     

丰田凯美瑞HV混合动力系统故障分析

正故障现象:客户反映车辆行驶过程中仪表上的发动机故障灯、防滑灯、制动系统故障灯都点亮,仪表中央显示屏提示"检查混合动力系统",同时空调制冷失效(如图1所示)。将车辆停靠路边并关闭点火开关之后,重启发动机,仪表上的"READY"灯熄灭,车辆处于停车状态。     

柴油机混合动力控制器硬件在环仿真系统设计

通过对客车柴油机混合动力控制系统的分析,设计开发了柴油机混合动力控制器(HCU)的硬件在环仿真系统,详细介绍了系统方案和混合动力仿真模型的建立,通过Matlab/Simulink,Matlab/Stateflow,C语言和汇编语言混合编程的方法,研制了HCU硬件在环仿真的软件系统;基于V850E MCU研制了仿真控制器HILECU,研制了HCU硬件在环仿真的硬件系统,最后以单轴并联混合动力系统为对象,进行了混合动力控制器HCU硬件在环仿真试验研究。     

国Ⅴ阶段天然气发动机车载诊断系统的设计

基于法规HJ 437-2008,总结了国Ⅴ阶段对CNG发动机车载诊断(OBD)系统的主要功能要求;对CNG发动机OBD系统关键诊断策略中关于催化器效率降低、氧传感器、缸内失火诊断策略进行了研究;同时,在添蓝控制器的基础上,针对CNG发动机的诊断策略和需求信号,对OBD系统进行硬件改进和软件设计;基于通用标准诊断仪ELM...     

基于OBD系统的失火诊断与排放分析

车载诊断(OBD)系统是实施国Ⅲ和国Ⅳ排放标准的核心内容,发动机失火诊断是OBD系统重要功能之一。指出了发动机失火的原因和危害;分析了OBD失火诊断监测方法、诊断原理和故障处理方法;根据OBD对发动机失火监控原理,说明了基于曲轴转速波动的失火诊断策略,并通过发动机失火发生装置模拟发动机失火,分析了失火时的曲轴转速波动和排放情况。试验研究结果表明,发动机发生失火时,曲轴转速有较大下降,HC和CO排放随着失火率的增加迅速升高。     

基于MPC555的混合动力电动汽车整车控制器硬件系统设计

介绍了一种基于32位MPC555微控制器的并联式混合动力电动汽车整车控制器(HCu)硬件系统的设计。阐述了几个重要模块的电路原理和系统的电磁兼容性设计方法。给出了利用硬件在环仿真测试和发动机台架试验进行硬件系统功能验证的结果。试验证明,所开发的HCU工作可靠、能够实现目标控制功能。     

福特·金牛座轿国车ABS/EBD系统故障诊断

福特·金牛座轿车ABS/EBD系统由电子控制单元(ECU)、液压控制单元(HCU)、电动油泵/马达、轮速传感器(4个)和ABS警告灯组成.ABS/EBD系统具有故障自诊断功能,当系统发生故障时,自诊断系统能够对故障进行自诊断,并将故障信息存储和输出.     

车载诊断系统失火诊断策略的研究

论述了车载诊断系统必须监测的两种失火类型。分析了利用瞬时曲轴角加速度法诊断发动机失火的原理,设计了车载诊断系统失火诊断策略。针对SQR372电控汽油机上模拟出的失火故障,利用基于KWP2000通信协议与VC软件编写的在线实时监控界面进行了监测。结果表明,该失火诊断策略能够及时准确地诊断出发动机失火故障。     

ABS线性增压可控温度区间的研究

针对防抱制动系统(ABS)低温环境下线性增压失效问题,通过阀芯的受力分析,推导了阀口开度自稳定条件;利用电磁场和流场的数值模拟,分析了环境温度对增压阀电磁力和流体作用力的影响;结果表明,要满足阀口开度自稳定条件,确保线性增压,ABS的可控温度区间为-17~120℃;利用HCU性能试验台对ABS的实测验证了仿真结果。     

2001款林肯·城市防抱死 制动系统/牵引控制系统故障诊断

林肯·城市ABS系统由 (ABCM)、液压控制单元 动压力控制阀、轮速传感器 成。 防抱死制动控制模块 (HCU)、电动油泵/电机制 (4个)和ABS警告灯等组 ABCM具有故障自诊断     

Fatigue design for plug/ring type gas welded joints of sts301l including welding residual stresses

This paper presents a fatigue design method for plug and ring type gas welded joints, which incorporates welding residual stress effects. A non-linear finite element analysis (FEA) was first performed to simulate the gas welding process. The numerically predicted residual stresses of the gas welds were then compared to experimental results measured using a hole drilling method. In order to evaluate the fatigue strength of the plug and ring type gas welded joints, a stress amplitude (σ _a ) _R taling the welding residual stress of the gas weld into account was introduced and is based on a modified Goodman equation incorporating the effect of the residual stress. Using the stress amplitude (σ _a ) _R , the ΔP-N _f relations obtained from fatigue tests for plug and ring type gas welded joints having various dimensions and shapes were systematically rearranged into (σ _a ) _R -N _f relations. It was found that the proposed stress amplitude (σ _a ) _R could provide a systematic and reasonable fatigue design criterion for the plug and ring type gas welded joints.     

Non-fragile multi-objective static output feedback control of vehicle active suspension with time-delay

This paper presents an approach to design a delay-dependent non-fragile H_∞/L₂–L_∞ static output feedback (SOF) controller for active suspension with input time-delay. The control problem of quarter-car active suspension with actuator time-delay is formulated to a H_∞/L₂–L_∞ control problem. By employing a delay-dependent Lyapunov function, new existence conditions of delay-dependent non-fragile SOF H_∞ controller and L₂–L_∞ controller are derived, respectively, in terms of the feasibility of bilinear matrix inequalities (BMIs). Then, a procedure based on linear matrix inequality optimisation and a hybrid algorithm of the particle swarm optimisation and differential evolution is used to solve an optimisation problem with BMI constraints. Design and simulation results of non-fragile H_∞/L₂–L_∞ controller for active suspension show that the designed controller not only can achieve the optimal performance and stability of the closed-loop system in spite of the existence of the actuator time-delay, but also has significantly improved the non-fragility characteristics over controller perturbations.     

Development of active front wheel steering control system keeping stable region in driving phase diagram

This paper presents a new active steering control system based on driving phase diagram (β _fr ?δ _f diagram). In order to make state variables to follow those of nominal vehicle model that was developed under no consideration of disturbance, Quadratic Programming Problem (QPP) is formulated, where time varying objective function minimizes the differences between nominal and actual parameters. The steering characteristic in active steering control system changes when the vehicle faces disturbance such as crosswind and flat tire, and driver tries to counteract it after recognizing the change. The proposed method defines a stability region on β _fr ?δ _f diagram. In order to make β _fr and δ _f remain in the stability region, a new model predictive controller is proposed. While conventional controllers are restrictive to satisfy the β _fr ?δ _f diagram based stability condition, the proposed controller ensures solution space and also plays a direct role to minimize the evaluation function in the constrained optimal control problem.     

Effects of injection parameters on the spray characteristics of swirl and slit injectors using the Mie-scattering method

We investigated the effects of injection parameters such as injection pressure, ambient pressure, and ambient temperature on spray characteristics. We calculated the turbulence occurring point (t _c ), defined as the time required to generate a vortex, and the deceleration point (t _b ), defined as the time when spray penetration begins to decelerate, to elucidate the breakup mechanism of the test injectors. The spray velocity coefficient (C_v) was obtained to evaluate the spray characteristics. As the ambient pressure increases in the case of a slit injector, C_v decreases. We investigated the effects of nozzle tip shape according to injection pressure, ambient pressure, and fuel properties on spray characteristics and provide a C_v value of 0.38 for the swirl injector with a spray angle of 60° and the slit injector under atmospheric conditions. The value of C_v in the case of a slit injector was reduced by increasing the ambient pressure. Our results suggest that C_v of a swirl injector is constant regardless of changes in ambient pressure, injection pressure, and fuel properties. On the other hand, C_v of a slit injector is altered by changes in ambient pressure.     

The high-expansion-ratio gasoline engine for the hybrid passenger car

A 50% reduction in CO₂ and fuel consumption has been achieved by the Toyota Hybrid System, which has been in mass production since 1997. This is achieved by the combination of two permanent magnet motors and a newly developed gasoline engine that is optimized in terms of its displacement and heat cycle. Delaying the closing timing of the intake valves effectively separates the compression ratio and expansion ratio, so that the expansion ratio, which is normally set from 9 : 1 to 10 : 1 to suppress knocking, can be set to 13.5 : 1. This new engine shows better than 230 g/kWh BSFC over a wide operating range. Motor-assisted quick start, improved catalyst warm-up, and the elimination of light-load firing allow the system to achieve very clean emissions levels.     

Model-based control system design in a urea-SCR aftertreatment system based on NH3 sensor feedback

This paper presents preliminary control system simulation results in a urea-selective catalytic reduction (SCR) aftertreatment system based on NH₃ sensor feedback. A four-state control-oriented lumped parameter model is used to analyze the controllability and observability properties of the urea-SCR plant. A model-based estimator is designed via simulation and a control system is developed with design based on a sliding mode control framework. The control system based on NH₃ sensor feedback is analyzed via simulation by comparing it to a control system developed based on NO_x sensor feedback. Simulation results show that the NH₃ sensor-based strategy performs very similarly in comparison to a NO_x sensor-based strategy. The control system performance metrics for NO_x index, urea index, urea usage, and NH₃ slip suggest that the NO_x sensor can be a potential alternative to a NO_x sensor for urea-SCR control applications.     

Research on exhaust emission control characteristics of a natural gas vehicle — Characteristics of methane oxidation reaction of three-way catalysts

Model gas reaction experiments were conducted to analyze the factors causing the conversion rate of hydrocarbons (consisting mainly of CH₄) to decline in the lean-mixture region, using a natural gas engine fitted with a three-way catalyst. The results showed that there was no decline in the conversion rate of methane in CH₄-O₂ reactions in the lean-mixture region. However, it was observed that oxidation of CH₄ was suppressed when either H₂O or NO was also present. It is thought that prior adsorption of H₂O and NO inhibits adsorption of CH₄ at active sites, resulting in a lower conversion rate.