Position self-learning method of cvvl mechanism for vehicle

Abstract

The invention discloses a CVVL (Continuously Variable Valve Lift) mechanism position self-learning method for a vehicle. The self-learning method comprises the following steps: obtaining a BLDC (Brushless DC) motor rotating angle range through primary CVVL mechanism position self-learning, and storing the rotating angle range into an EEPROM (Electrically Erasable Programmable Read-Only Memory); carrying out the CVVL mechanism position self-learning again, and if a CVVL mechanism position self-learning condition cannot be met, quitting the CVVL mechanism position self-learning; if the CVVL mechanism position self-learning condition is met, triggering the CVVL mechanism position self-learning; if BLDC position learning for a top dead center and a bottom dead center is successful, calculating a difference between the BLDC rotating angle ranges of the top dead center and the bottom dead center, taking an absolute value of the difference, and carrying out rotating angle range calibration to obtain a CVVL mechanism position; if the rotating angle range calibration fails, obtaining the CVVL mechanism position by using the BLDC rotating angle range stored in the EEPROM; if only the position learning for the bottom dead center is successful, taking the obtained position of the bottom dead center as an initial position of a CVVL mechanism; and if only the position learning for the top dead center is successful, subtracting the corresponding BLDC rotating angle range during learning of the position of the top dead center from the BLDC rotating angle range stored in the EEPROM, thus obtaining the initial position of the CVVL mechanism. By applying the CVVL mechanism position self-learning method for the vehicle, the real-time position of the CVVL mechanism can be accurately calculated.

Description

technical field [0001] The invention relates to the field of automotive electronics, in particular to a position self-learning method of a CVVL mechanism for a vehicle. Background technique [0002] Continuously variable valve lift (CVVL for short) technology is one of the important fuel-saving technologies for vehicle gasoline engines. It can play the same role as the traditional throttle valve in controlling the load of gasoline engines. Adjust the intake air volume in the cylinder to meet the requirements of the engine for different working conditions. When the engine is under high-load conditions, the large valve lift can reduce the resistance at the valve, increase the intake air volume, and increase the power of the engine to meet the requirements of engine power; Valve lift, control the amount of mixed gas entering the cylinder, and realize no-throttle load control, which can significantly reduce the engine's ventilation loss, significantly reduce fuel consumption, a...

AI Technical Summary

Problems solved by technology

[0005] 1. The feedback signal of the eccentric shaft sensor can indicate the absolute position of the CVVL mechanism, but the accuracy of the sensor itself is low, and it is difficult to meet the high precision requirements of valve lift control;

[0006] 2. The long-term reciprocating action of the CVVL mechanism and the mechanical dead point of the impact mechanism will cause changes in the initial position. The use of conventional methods will inevitably lead to inaccurate calculation of the initial position

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