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The paper introduces an on-board fault diagnosis strategy based on analytical redundancy suit for automated mechanical transmission (AMT). Through experiment and theory analysis an identified engine model, a gear box model and a dry clutch model controlled by hydraulic actuators are respectively established. The information redundancy in the local models of the power train and the structure logic relations among the assemblages is used to detect and diagnose the fault in the sensors, the actuators and the unit assemblages of the AMT system. The method has been used in the AMT control system developed for the SVWSANTANA2000.

With the rapid development of electronics and the growing demand for higher vehicle performance, driving environment recognition and self-adaptation are becoming more and more important for the vehicle control systems. A two-level intelligent real-time driving environment recognition architecture is proposed in this paper. The lower level does the fundamental recognition according to “driving condition” algorithms and the upper level makes inference and decision based on rules. Also, the application of the driving environment recognition in the automatic mechanical transmission (AMT) is introduced.

The use of hydrodynamic transmission with lock-up clutch for a Chinese city bus leads to good fuel economy and ease of operation. Many examples have shown that the microprocessor-based control system used in a vehicle powertrain has the advantage with high control speed over a manual one, but most of the time, its control qualities are poor, especially when outside conditions change. In this paper, a synthetic control method for hydrodynamic transmission for a Chinese city bus is proposed with respect to control qualities of lock-up control. The lock-up control process is divided into two steps, i.e., ‘estimate’ step and ‘fine’ step, so we can apply different control schedules to realize different control demands and get better control qualities.

The city buses start and stop frequently, therefore significant amount of kinetic energy is wasted on friction plates. In order to retrieve this amount of energy, various feasible and efficient energy storage systems have been suggested by researchers to reuse the energy to improve the efficiency of the city bus. Due to small size, high energy density, cleanliness and easiness to absorb/reuse the energy, the storage system of flywheel is hopeful to be coming into wide use. In this paper, a dynamic model is analyzed to study the characteristics of the system using time series. Finally, comparison between simulation and experiment is given.

The accuracy of the injection rate meter based on W. Zeuch's method in the measurement of multiple injection rate and amount was calibrated using a small cam driven piston that is driven by an electric motor. For the pre- or early-injection, a sensor with a high sensitivity can be applied to measure the small pressure increase due to the small injection amount. In case of the multiple injection that has the post and/or late injection, a pressure sensor with a low sensitivity must cover not only the large pressure increase due to the main injection but also the small pressure increase due to the post and/or late injection because the output of the high sensitivity sensor is saturated after the main injection. So the linearity of the low sensitivity pressure sensor was calibrated with the cam driven piston prior to the experiment with the actual injection system.

A newly developed GYB-100 hydrodynamic transmission consisting of DFZFB-323 torque converter with lock-up clutch and power shift gearbox for Chinese city bus has been put into operation. The locking-up process of the torque converter is a transient one, and it will bring great shudder to powertrain and thus reduce the lifespan of the clutch. Measures must be taken to eliminate the shudder. In this paper, the city bus powertrain is supposed to be a concentrated mode, i.e, a spring-mass system having multi-degrees of freedom. From analysis of dynamic characteristics of the lock-up clutch it gives that the friction characteristics of the lock-up clutch are of main importance for avoidance of shudder and the proper control of oil pressure operating the lock-up clutch and oil-filling time will lead to improved friction characteristics. The judgement of quality of the lock-up clutch is presented. Using modern control theory, we get optimal control schedule of the lock-up clutch.

The paper details an analytical redundancy fault diagnosis method of automated mechanical transmission (AMT) control system. The basic principle of AMT is depicted. After concisely introducing the models of engine, gear box and clutch, which are used to provide redundant information, the diagnostic logic is illustrated in detail. The information redundancy in the local models of the powertrain and the structure logic relations among the assemblages is used to detect and diagnose the faults of the sensors, the actuators and the unit assemblages of the AMT system. The fault codes and fault process measures are listed out.