Valve Timing Controller Phase Correction for Engine Startability
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Solution Overview
Problem
Existing valve timing controllers for internal combustion engines face challenges in quickly starting the engine after automatic stop due to increased load on the starter motor, which degrades startability, and lack precise control accuracy for setting the opening/closing timing of the intake camshaft.
Innovation Solution
A valve timing controller that includes a driving-side and driven-side rotation member, a phase regulating mechanism using an electric motor to set and maintain the relative rotation phase, a detection unit to monitor the phase, and a correction control portion to adjust the phase closer to the stop phase when deviations occur, ensuring accurate positioning of the relative rotation phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the valve timing controller is controlled to the most retarding phase when the engine is automatically stopped, then the compression ratio is reduced enabling quick starting, but the relative rotation phase may be displaced to the advancing side after stopping, increasing the load on the starter motor and degrading startability
Solution Approach 1:
The patent employs feedback control by detecting the actual relative rotation phase with a detection unit and comparing it to the target stop phase. When displacement beyond a set amount is detected after engine stopping, the correction control portion activates to return the phase to the correct position, ensuring reliable starting conditions while maintaining the compression ratio reduction benefit.
Solution Approach 2:
The patent performs preliminary control by setting the valve timing to the most retarding phase before engine stopping to reduce compression ratio and facilitate quick starting. The correction mechanism is prepared in advance to adjust the phase if displacement occurs, ensuring both quick starting and reliable startability are achieved.
2Ease of operation
If the electric actuator is driven for a set time or by a set amount to set the opening/closing timing, then the control process is simple, but the control accuracy is insufficient
Solution Approach 1:
The patent replaces open-loop control (fixed time/amount driving) with closed-loop feedback control. The detection unit continuously monitors the relative rotation phase, and the control portion adjusts the actuator driving amount based on the detected phase deviation, achieving high positioning accuracy while maintaining operational simplicity through automated feedback adjustment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for precise control of the valve timing, reducing the load on the starter motor and enabling quick engine starting by maintaining the relative rotation phase at the optimal stop phase, thereby improving startability and control accuracy.
Implementation Method 1
a phase regulating mechanism that sets a relative rotation phase of the driving-side rotation member and the driven-side rotation member by a driving force of an electric motor
Data Source
AI summary
A valve timing controller includes: a driving-side rotation member rotatable around a rotation axis and rotating in synchronization with a crankshaft of an internal combustion engine; a driven-side rotation member rotatable around the rotation axis and rotating integrally with a camshaft of the engine; a phase regulating mechanism setting a relative rotation phase of the driving-side and driven-side rotation members by an electric motor; a detection unit detecting the relative rotation phase; a stop control portion displacing the relative rotation phase by controlling the electric motor to stop the engine after the relative rotation phase reaches a stop phase; and a correction control portion displacing the relative rotation phase in a direction closer to the stop phase by controlling the electric motor, when the relative rotation phase is displaced beyond a set amount from the stop phase, in a state where the engine is stopped by the stop control portion.