Variable Valve Timing Actuator Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable valve timing systems consume unnecessary power during engine stop as they maintain actuator operation to achieve precise valve timing, even after the valve timing has reached the target for the next engine start, due to fixed power supply periods.
Innovation Solution
A variable valve timing apparatus with an actuator operation amount setting portion that adjusts the actuator's operation based on the deviation between actual and target valve timing, setting the operation amount to zero when the deviation is within a certain determination value, and increasing this value during engine stop to reduce power consumption by stopping actuator power supply once the target is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the actuator is operated to change the valve timing at the time of engine stop with a fixed power supply period, then the valve timing can be changed to the target position, but unnecessary power consumption occurs after the valve timing reaches the target
Solution Approach 1:
The patent applies dynamics by making the determination value adaptive rather than fixed. The control device switches between a first determination value (during engine stop) and a second determination value (during engine operation), allowing the system to dynamically adjust its tolerance threshold based on operational context. This resolves the contradiction by enabling early termination of actuator operation during engine stop when lower precision is acceptable, while maintaining strict precision control during engine operation.
Solution Approach 2:
The patent changes the parameter of determination value based on engine operational state. By setting a larger first determination value during engine stop and a smaller second determination value during engine operation, the system optimizes power consumption during stop while ensuring precision during operation. This parameter switching strategy directly addresses the technical contradiction by allowing relaxed control during low-demand periods.
2Device complexity
If a fixed determination value is used for actuator control, then the control logic is simple, but power consumption increases during engine stop due to continued actuator operation
Solution Approach 1:
The control device dynamically switches between two determination values based on engine operational state (stop or operation). This dynamic adaptation allows the system to use a more generous tolerance during engine stop, enabling earlier termination of actuator power supply and reducing overall power consumption, while maintaining appropriate precision during engine operation.
Solution Approach 2:
The patent implements parameter changes by switching the determination value based on engine state. The first determination value (larger) is applied during engine stop to reduce power consumption, while the second determination value (smaller) is applied during engine operation for higher precision. This parameter switching resolves the contradiction between control simplicity and power consumption.
3Use of energy by moving object
If the determination value is set large during engine stop, then power consumption is reduced by stopping actuator operation early, but valve timing precision may be compromised
Solution Approach 1:
The patent applies local quality by using different determination values for different operational contexts. During engine stop, a larger determination value is used where lower precision is acceptable and power conservation is prioritized. During engine operation, a smaller determination value is used where higher precision is critical. This context-dependent quality adjustment resolves the contradiction between power consumption and precision.
Solution Approach 2:
The control device changes the determination value parameter based on engine operational state. By setting a larger first determination value during engine stop, the system allows earlier termination of actuator operation, reducing power consumption. The smaller second determination value during engine operation ensures high precision when needed. This parameter adaptation resolves the precision-power consumption trade-off.
Data Source
AI summary
A convergence determination of intake valve phase control is made by comparing a phase deviation of an intake valve from a target phase with a convergence determination value. At the time of convergence, it is determined that the intake valve phase has reached the target phase, so that the required phase-change amount of a camshaft is set to zero and therefore the actuator operation amount is also set to zero. At the time of engine stop when the target phase has a fixed value, after convergence of the intake valve phase control, the operation of the actuator is stopped. In addition, during the course of engine stop, the convergence determination value is set to be switched from the time of engine operation so that the convergence determination of the intake valve phase control is made in more relaxed conditions compared with at the time of engine operation.