Variable Valve Timing Control Unit for Engine Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable valve timing mechanisms face challenges in accurately controlling valve phase during engine idling, particularly when the engine is cold or operating at low speeds, leading to potential noise issues and inefficiencies due to the difficulty in transmitting rotational force and maintaining precise actuator operation.
Innovation Solution
A control unit and method that restricts the range of valve phase change within a region with a higher speed reduction ratio during idling, using a target idle speed setting unit and phase restriction unit to manage actuator operation and reduce noise, while also considering engine temperature to maintain appropriate valve phase control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the valve phase is controlled with a variable speed reduction ratio based on phase region, then the actuator operation efficiency is improved, but the control accuracy during idling deteriorates due to inappropriate change ratios in certain phase regions
Solution Approach 1:
The patent applies dynamics by making the speed reduction ratio changeable based on the valve phase region. The control unit dynamically adjusts the ratio between actuator operation amount and valve phase change amount according to the current phase region, optimizing actuator efficiency while maintaining control accuracy through adaptive parameter adjustment.
Solution Approach 2:
The patent changes the control parameter (speed reduction ratio) based on the valve phase region. By dividing the control range into multiple regions with different speed reduction ratios, the system optimizes actuator operation efficiency in each region while preventing inappropriate control during idling by selecting suitable phase regions.
2Adaptability or versatility
If the target idle speed is variably set based on vehicle state, then the engine adaptability is improved, but the valve phase control complexity increases due to the need to coordinate variable idle speed with phase region constraints
Solution Approach 1:
The patent segments the valve phase control range into multiple regions, each with characteristic speed reduction ratios. When idle speed is variably set, the control unit determines the appropriate phase region and applies the corresponding speed reduction ratio, simplifying the control logic through region-based segmentation rather than continuous complex calculations.
Solution Approach 2:
The patent performs preliminary classification of the valve phase into discrete regions with predetermined speed reduction ratios. This preliminary segmentation allows the control system to handle variable idle speed scenarios by simply selecting the appropriate pre-defined region and ratio, reducing control complexity compared to real-time continuous optimization.
3Adaptability or versatility
If the camshaft is rotated by electric motor, then the system flexibility is improved, but the torque transmission efficiency deteriorates due to difficulty in obtaining rotation torque
Solution Approach 1:
The patent replaces the traditional mechanical torque transmission system with an electric motor-driven system. The electric motor provides flexible and controllable torque to rotate the camshaft, improving system adaptability while the control unit optimizes the actuator operation amount to minimize energy loss and maximize torque transmission efficiency.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An idling-time target phase setting unit (130) variably sets a target phase based on a target idle speed that is set by a target idle speed setting unit. (110) Especially, when the target idle speed is lower than a predetermined rotational speed and operating noise of a variable valve timing mechanism (2000) is easily heard by, for example, a driver, the.idling-time' target phase setting unit (130) sets the target phase so that a range, in which the valve phase is allowed to change, is restricted within a phase region where a speed reduction ratio is high and the operating noise is relatively low.