Valve Timing Controller Cogging Torque Phase Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing valve timing controllers face challenges in accurately adjusting torque balance at low engine speeds, leading to difficulties in starting the engine due to variations in cam torque with temperature conditions.
Innovation Solution
A valve timing controller incorporating an electric motor generating a cogging torque on a motor shaft, with a current control system and phase-changing mechanism, ensures the motor shaft is held at a suitable starting phase by overcoming cam torque, even when deenergized, thus maintaining precise valve timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque balance is adjusted using a sub-brake and spring in the phase-changing mechanism, then the middle phase can be obtained, but the accuracy of the middle phase deteriorates when cam torque varies significantly with temperature at low engine speeds
Solution Approach 1:
The patent extracts the sub-brake from the system and replaces it with an electromagnetic brake. This allows for more precise control of the brake shaft's rotational phase by independently controlling the electromagnetic brake torque, eliminating the difficulty of adjusting torque balance with a mechanical sub-brake when cam torque varies with temperature.
Solution Approach 2:
The patent changes the control parameter from mechanical torque balance adjustment to electrical current control of the electromagnetic brake. By controlling the current supplied to the electromagnetic brake, the brake torque can be precisely adjusted to maintain accurate middle phase positioning even when cam torque varies with temperature conditions.
2Adaptability or versatility
If a sub-brake is provided besides an electromagnetic brake to obtain middle phase, then phase changing capability is achieved, but device complexity increases and torque balance adjustment becomes difficult
Solution Approach 1:
The patent removes the sub-brake from the system entirely, retaining only the electromagnetic brake. This simplifies the device structure while maintaining phase changing capability through electrical control, eliminating the complexity of mechanical torque balance adjustment between multiple braking components.
Solution Approach 2:
The patent replaces the mechanical sub-brake with an electrical control system (electromagnetic brake with current control). This substitution transforms the mechanical torque balance adjustment problem into an electrical control problem, which can be more precisely and easily managed through current regulation.
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 solution stabilizes the starting phase of the engine, ensuring suitable valve timing for engine operation, particularly during starting, by generating a cogging torque greater than the cam torque, thereby improving engine startability and performance.
Implementation Method 1
an electric motor generating a cogging torque on a motor shaft
Data Source
AI summary
A valve timing controller includes an electric motor generating a cogging torque on the motor shaft, an current control means for controlling an electricity supplied to the electric motor, and a phase-changing mechanism varying a relative rotational phase between the crankshaft and the camshaft according to a rotation of the motor shaft. The cogging torque has a peak value which is greater than an absolute value of a cam torque applied to the motor shaft from the camshaft through the phase-changing mechanism.