Method for estimating indicating torque of engine based on nonsingular terminal sliding mode observer

Abstract

The invention discloses a method for estimating an indicating torque of an engine based on a nonsingular terminal sliding mode observer. The method comprises the following steps of: establishing an accurate nonlinear engine crankshaft dynamical model; performing real-time measurement on crankshaft angle and engine speed, taking as an observer input and performing differential operation; and utilizing the nonsingular terminal sliding mode observer to change an estimating value of the indicating torque, thereby causing the estimating value of the crankshaft angular velocity gradually approach to the constantly changing practical measurement value. According to the method disclosed by the invention, the nonsingular terminal sliding mode observer is utilized to online estimate the indicating torque of the engine, has excellent robustness to the modeling error and the parameter perturbation, is short in convergence time and is high in estimating precision. According to the method disclosed by the invention, the estimating precision of the indicating torque is guaranteed.

Description

technical field [0001] The invention belongs to a method for estimating indicated torque of an automobile engine, in particular to an estimating method for indicated torque of an engine based on a non-singular terminal sliding mode observer (NTSMO). Background technique [0002] Indicated torque is an important parameter of engine power performance. Real-time and reliable acquisition of indicated torque can not only correctly evaluate engine performance, monitor faults in real time, but also implement relevant strategies for optimal control of the engine and transmission. In the case of changes in speed and load, it can effectively improve the fuel economy, driving comfort and car safety of the car. In addition, since the indicated torque of the engine cannot be obtained directly, the indicated torque can be calculated by installing the cylinder pressure sensor to obtain the cylinder pressure, but this method is limited in practical application. Therefore, how to indirectly...

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Problems solved by technology

The input estimation problem is transformed into a control tracking problem; literature [12] uses a sliding mode observer to estimate the dynamic torque, that is, the difference between the indicated torque and the load torque, which can avoid the acquisition of the load torque, and use the sliding mode observer The estimation robustness of is better, but the convergence time needs to be improved

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