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The internal combustion engine and motor should be controlled coordinately to meet the demand of smooth power transfer and good drivability especially during transient conditions for parallel hybrid powertrain system. This paper presents the essential technology of how to estimate the engine torque by the measurement and processing of instantaneous crankshaft speed. One multi-injection gasoline engine and one turbocharged diesel engine are selected to manifest the algorithm of engine torque estimation and the experiments show fairly good results for both engines. Consequently an engine torque sensor can be easily calibrated and applied to feedback engine torque in coordinating control.

Cylinder-by-cylinder variation control is an important issue to the solenoid-based electronic diesel engines. Large variation causes bad engine performance and should be avoided. This paper presents the research results achieved by the author on the issue of cylinder-by-cylinder closed-loop feedback control of diesel engines. Momentary flywheel speed is processed to estimate the cylinder-by-cylinder variation. Utilizing a special signal modulation technique, the new cylinder-by-cylinder variations detection algorithm is worked out, which has a good adaptive capability to fluctuation characteristics of the momentary flywheel speed under variant operating conditions. This algorithm extends the variations detection range from the low speed and steady state engine conditions to the whole engine steady operating condition of the engine and some transient conditions. The closed-loop control of the cylinder-by-cylinder variation is carried out on the engine test bench.

Electronic diesel engine control is one of the most important research subjects on automotive engines. This paper presents the research results achieved by the authors on the issue of mean torque closed-loop feedback control of diesel engines. To achieve mean torque feedback, momentary flywheel speed is processed and a new symbolic index is presented in this paper. The relationship between the symbolic index and mean effective torque is investigated. On the natural aspiration diesel engine, mean effective torque is proportional to the index when engine speed does not change. On the turbo-charged diesel engine, as the variation of the intake air mass, the compression pressure changes at different mean torque. Hence the relationship between the index and mean torque is not linear. The boost pressure sensor is used to compensate the influence of the compression pressure. Then the mean torque is identified by the index and the closed-loop control system is built.

This paper presents two mean-value models of automotive powertrain equipped with turbocharged diesel engine and automatic transmission. The first model includes all dynamics of automotive powertrain while the second model involves the main dynamic processes except transmission shaft dynamics. Modeling analysis is carried out in frequency domain. It is confirmed that the second model, which eliminates transmission shaft dynamics can accurately describe automotive powertrain within the vehicle frequency boundary compared with the first model. A sliding mode controller that characterizes the robustness is designed based on the second model subsequently. Applying serial variable structure sliding mode control with multi sliding mode surfaces, accurate vehicle speed tracking is realized in simulation consequently.

Momentary flywheel speed is the most convenient signal to detect cylinder-by-cylinder variations. Though some papers had indicated that torsional vibration of crankshaft should be considered at high-speed condition [1][2][3], it is still not very clear how to quantitatively analyze the influence of the vibration upon the flywheel speed. The goal of this paper is to reveal the influence and to find a way to compensate it. At first the transform functions of each cylinder torque to flywheel speed are analyzed. Then based on the transform functions, rigid crankshaft model and flexible crankshaft model are compared. The influence of the torsional vibration on the flywheel speed is investigated. Finally, a compensator of the influence is built. The compensator is verified by the simulation results. After compensation, the measured flywheel speed can be processed under the rigid crankshaft model.

Momentary camshaft speed signal of in-line fuel pump of diesel engines is investigated in this paper. First, time domain characteristics and frequency characteristics of camshaft speed are analyzed. Secondly, the relation between momentary camshaft speed and fuel pressure in the pump is studied. The work indicates that pulsed fuel pump pressure is a result of camshaft speed fluctuation. Thirdly, the relation among momentary speed fluctuations, different injection timing and injection duration are studied. Correlation of the fluctuation amplitude and injected fuel quantity is calibrated. The basic results show that it is possible to estimate cylinder-by-cylinder fuel injection quantity. Finally, the relation between camshaft dynamics and pump cam profile design is discussed. The results indicate that momentary camshaft speed is a useful signal for injection system design, diagnosis and control.

The noise, caused by tooth to tooth tolerance of flywheel starter ring in momentary crankshaft speed signal, is analyzed and eliminated in this paper. At first the relationship of the noise amplitude with engine speed and engine load are analyzed. Then under the assumption that the noise is independent with the flywheel speed fluctuations, a noise generation model of speed measurement is established. Finally, a new algorithm based on double speed sensors is presented to identify and eliminate the noise. The algorithm is verified by the experiment results to be more efficient than conventional process methods such as filter or static calibration.

Injection rate control is considered as an effective way to optimize diesel combustion process, decrease emission and improve fuel economy. There are many injection rate shaping devices, but most of them still suffer from structure complexity and parameter sensitivity which limit their effectiveness and practicality. A new initial injection rate control method in solenoid-controlled diesel injection systems is introduced in this paper. The basic idea of this method is to maintain a small spill passage between plunger chamber and inlet port during initial injection period. The initial injection rate can be regulated by changing the closing timing of the solenoid-controlled spill valve. This method has the advantages of simple construction, flexible adjustment and stable performance. Computer aided analysis and design based on a simulation program of the system is conducted to compare and select the sizes of the small spill passage according to their effect on injection characteristics.