Variable Vane Pump Dual Control Chambers Equilibrium Pressure
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Solution Overview
Problem
Conventional variable capacity vane pumps operate at a single equilibrium pressure, leading to inefficiency at varying engine speeds, as they either over-pump at lower speeds or under-pump at higher speeds, wasting energy and causing potential wear on the engine.
Innovation Solution
A variable capacity vane pump design featuring two control chambers and a return spring, allowing for selective adjustment of the pump's volumetric capacity by pressurized fluid, enabling two selectable equilibrium pressures and reduced reaction forces on the pivot pin, thereby optimizing performance across different engine speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single equilibrium pressure is used in conventional variable capacity vane pumps, then the pump structure is simple, but the pump operates inefficiently at varying engine speeds, wasting energy and causing potential wear
Solution Approach 1:
The control ring is divided into multiple control chambers (first control chamber and second control chamber), each capable of receiving pressurized fluid from different sources. This segmentation allows independent control of different pressure zones, enabling the pump to achieve multiple equilibrium pressures while maintaining a relatively compact structure.
Solution Approach 2:
The control ring serves multiple functions: it acts as both the capacity adjusting element and the structural component housing multiple control chambers. The same control ring structure is used to achieve both single-pressure and multi-pressure operations by selectively supplying pressurized fluid to different chambers, reducing the need for additional separate components.
2Reliability
If the equilibrium pressure is selected to meet worst case (high operating speed) conditions, then the engine is protected from wear, but the pump operates at higher capacity than necessary at lower speeds, wasting energy
Solution Approach 1:
The pump transitions from a static single equilibrium pressure system to a dynamic multi-equilibrium pressure system. By selectively supplying pressurized fluid to different control chambers based on operating conditions, the pump can dynamically adjust its equilibrium pressure to match actual system requirements, ensuring engine protection while eliminating energy waste at varying speeds.
Solution Approach 2:
The system changes the equilibrium pressure parameter dynamically by selectively activating different control chambers. At high operating speeds, one equilibrium pressure setting is used to protect the engine, while at lower speeds, a different equilibrium pressure setting reduces energy waste, allowing the same pump to adapt to different operational demands.
3Productivity
If multiple control chambers are added to enable selectable equilibrium pressures, then pump efficiency improves, but the pump housing size increases
Solution Approach 1:
The multiple control chambers are nested within the existing pump housing structure. The first control chamber and second control chamber are arranged concentrically or adjacently within the same housing space, utilizing the existing structural volume efficiently. This nesting approach allows multiple control chambers to coexist without proportionally increasing the overall pump housing size.
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
The design allows for efficient operation at multiple equilibrium pressures, reducing energy wastage and minimizing wear on the pivot pin, ensuring smoother control and extended pump lifetime.
Implementation Method 1
a capacity adjusting element, in the form of a pump control ring that can be moved to alter the rotor eccentricity of the pump and hence alter the volumetric capacity of the pump
Implementation Method 2
the pressure in the control chamber acting to move the control ring, typically against a biasing force from a return spring, to alter the capacity of the pump
Implementation Method 3
a biasing force from a return spring
Data Source
AI summary
A variable capacity vane pump includes a first control chamber between a pump casing and a first portion of a pump control ring. The first portion of the control ring circumferentially extends on either side of a pivot pin. A second control chamber is provided between the pump casing and a second portion of the pump control ring. The first and second control chambers are operable to receive pressurized fluid to create a force to move the pump control ring to reduce the volumetric capacity of the pump. A return spring biases the pump ring toward a position of maximum volumetric capacity.