Variable Valve Timing Hydraulic Control for Locking Release
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Solution Overview
Problem
Hydraulically-actuated variable valve timing mechanisms face challenges in reliably releasing the locking member from the locking state during engine acceleration, leading to difficulties in determining a suitable valve-opening phase due to variations in oil pressure.
Innovation Solution
A valve timing control device with a hydraulic control valve system that adjusts the degree of opening based on detected oil pressure to maintain low oil pressure in the advanced and retarded angle chambers, ensuring stable release of the locking member and prompt phase control, aided by an oil temperature sensor for viscosity correction and a variable oil pump for targeted oil discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the timing of transition to phase control is retarded to ensure successful release of the stopper pin, then the reliability of locking mechanism release is improved, but the responsiveness during engine acceleration deteriorates
Solution Approach 1:
The patent applies dynamics by making the hydraulic control valve's degree of opening adjustable based on real-time oil pressure conditions. The control valve transitions from a static opening state to a dynamic one where the opening degree is continuously adjusted according to oil pressure variations, enabling both reliable lock release and rapid phase control transition during engine acceleration
Solution Approach 2:
The patent changes the parameter of oil pressure by dynamically adjusting the hydraulic control valve's opening degree. When oil pressure increases during engine acceleration, the control valve reduces its opening degree to maintain appropriate pressure levels, ensuring both reliable locking mechanism release and prompt phase control transition
2Productivity
If the degree of opening of the hydraulic control valve is increased to improve phase control speed, then the productivity is improved, but the oil pressure stability deteriorates
Solution Approach 1:
The patent implements feedback by using a hydraulic sensor to detect oil pressure and feeding this information back to the hydraulic control valve controller. The controller continuously adjusts the control valve's opening degree based on the detected oil pressure, creating a closed-loop system that maintains oil pressure stability while enabling rapid phase control transitions
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
Enables reliable and prompt release of the locking member and phase control during engine acceleration, improving engine efficiency and reducing load on the oil pump, thereby enhancing fuel efficiency.
Implementation Method 1
a hydraulic control valve which controls the oil pressures supplied to the locking mechanism, the advanced angle chamber and the retarded angle chamber
Implementation Method 2
releases the locking member from a locking state through supply of an oil pressure
Implementation Method 3
each of the advanced angle chamber and the retarded angle chamber being used to change a phase angle of the camshaft relative to the crankshaft by being supplied with an oil pressure
Data Source
AI summary
Provided are a variable valve timing mechanism, an oil pump supplying oil to a hydraulically-actuated device including the variable valve timing mechanism, and a hydraulic control valve which controls oil pressures supplied to a locking mechanism (which includes a locking member configured to fix a phase angle of a camshaft relative to a crankshaft) of the variable valve timing mechanism, an advanced angle chamber and a retarded angle chamber. While an oil pressure in a hydraulic path detected by a hydraulic sensor increases, a hydraulic control valve controller adjusts a degree of opening of a hydraulic control valve according to the detected oil pressure at a time of releasing the locking member from a locking state, to reduce the oil pressure to be supplied to the advanced angle chamber or the retarded angle chamber used to change the phase angle of the camshaft relative to the crankshaft.