Variable Capacitance Pump Control Valve Hydraulic Circuit
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Solution Overview
Problem
The use of a variable capacitance pump in internal combustion engines leads to a reduction in oil supply quantity to the main oil gallery, compromising the operation response characteristic of valve timing control apparatuses, especially at engine start, due to premature operation of the control valve.
Innovation Solution
A control valve and hydraulic circuit design that varies the drained flow quantity of the variable capacitance pump in response to pressure changes, with the control valve moving at a lower pressure than the pump's variation pressure, ensuring sufficient oil supply to the main oil gallery by optimizing the hydraulic pressure circuit and valve timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a variable capacitance pump is used to reduce power loss, then power loss is reduced, but oil supply quantity to the main oil gallery decreases
Solution Approach 1:
A control valve is introduced as an intermediary device between the variable capacitance pump and the main oil gallery. The control valve regulates oil flow to ensure sufficient supply to the main oil gallery while the pump operates with reduced capacity, thereby resolving the contradiction between power loss reduction and oil supply quantity maintenance
Solution Approach 2:
The system dynamically changes operational parameters by adjusting the pump capacitance based on engine conditions. The control valve modifies flow parameters to maintain adequate oil supply to the main oil gallery even when the pump operates at reduced capacity, enabling power loss reduction without compromising lubrication requirements
2Speed
If the control valve operates before the variable capacitance pump, then oil supply priority to the valve timing control apparatus is improved, but oil supply quantity to the main oil gallery is reduced
Solution Approach 1:
The control valve and variable capacitance pump operations are dynamically coordinated based on real-time pressure conditions. The control valve is designed to operate at lower pressure thresholds than the pump activation pressure, creating a dynamic sequence where the control valve responds first to timing control needs while the pump subsequently provides bulk oil supply, thereby maintaining both rapid response and adequate oil quantity
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 design enhances the oil supply quantity to the main oil gallery, improving the operation response characteristic of the valve timing control apparatus by reducing excessive supply regions and power loss, while maintaining required hydraulic pressures for lubrication and valve timing control.
Implementation Method 1
a control valve (22) which controls an oil flow quantity to the supply section by moving a valve body (29) in accordance with a pressure of the introduction section (15a)
Implementation Method 2
a variable capacitance pump (19) which varies a drained flow quantity in accordance with a drained pressure of oil
Data Source
AI summary
In a hydraulic pressure circuit including an introduction section through which oil is introduced, a main passage section installed at a downstream side of the introduction section to be communicated with a supply section through which oil is supplied to each of slide sections of an internal combustion engine, a branch passage branched from the main passage section to supply oil to a hydraulic pressure actuator, and a control valve having a valve body which is moved in accordance with a pressure of an upstream side thereof, and a variable capacitance pump configured to drain oil to the introduction section, the variable capacitance pump is configured to vary a drained flow quantity in accordance with the drained pressure of oil and a pressure under which the oil drained flow quantity is started to be varied is higher than a pressure under which the valve body is started to move.