Variable Displacement Lubricant Pump Preload Control
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Solution Overview
Problem
Existing variable displacement lubricant pumps fail to maintain constant lubricant pressure across varying engine conditions such as temperature and rotational speed, leading to inefficient lubrication in internal combustion engines.
Innovation Solution
A variable displacement lubricant pump with a preload control arrangement that adjusts the preload of a control spring to provide two nominal pressure levels, using a pressure control valve and preload control valve to manage pressure in the pump outlet port, allowing the control ring to shift between high and low pumping volumes based on lubricant discharge pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure control valve is used to maintain constant discharge pressure, then pressure stability is improved, but the system cannot adapt to varying lubricant pressure demands under different engine working conditions
Solution Approach 1:
The pressure control valve is designed with a movable preload plunger that can dynamically adjust the spring preload force. This allows the valve to adapt its pressure control characteristics based on engine working conditions, transitioning from a static to a dynamic system that can maintain reliable pressure control while adapting to varying demands.
Solution Approach 2:
The invention changes the parameter of spring preload force by introducing a movable preload plunger that can adjust the compression of the spring. This parameter adjustment enables the pressure control valve to provide different nominal pressure levels (first and second levels) according to engine conditions, resolving the contradiction between pressure stability and adaptability.
2Device complexity
If a fixed spring preload is used in the pressure control valve, then device simplicity is maintained, but the pump cannot provide variable pressure levels to meet different lubrication demands
Solution Approach 1:
A preload control valve is introduced as an intermediary component to adjust the spring preload force. This intermediary mechanism allows simple adjustment of the pressure control characteristics without significantly complicating the overall device structure, enabling variable pressure levels while maintaining relative simplicity.
Solution Approach 2:
The preload control valve uses hydraulic pressure from the pump outlet to actuate the preload plunger, adjusting the spring preload force. This pneumatic/hydraulic approach provides automatic adjustment capability without complex mechanical linkages, maintaining device simplicity while enabling variable pressure capability.
3Productivity
If the control ring is pushed into high pumping volume direction, then lubricant flow rate is improved, but discharge pressure may become inconsistent with engine lubrication demands
Solution Approach 1:
The pressure control valve with adjustable spring preload provides feedback control of the discharge pressure. By adjusting the preload plunger, the spring force is modified to maintain the desired pressure level, ensuring that high flow rate operation does not compromise pressure consistency with engine lubrication demands.
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 solution ensures reliable and efficient lubrication by maintaining consistent pressure levels across different engine conditions, enhancing mechanical reliability and longevity while simplifying production and assembly.
Implementation Method 1
a control spring configured to preload the control plunger into a closed position against the pump outlet pressure
Implementation Method 2
a first pressure control chamber configured to push the control ring into a high pumping volume direction
Implementation Method 3
an input pressure plunger connected with the control plunger and configured to be charged with a pump outlet pressure
Implementation Method 4
a preload control valve configured to control a lubricant pressure in the preload cylinder
Data Source
AI summary
A lubricant pump for pumping a pressurized lubricant to an engine includes a shiftable control ring, a pump rotor, a pump outlet port, a pressure control system and a preload control arrangement. The pressure control system comprises a first pressure control chamber, a first pressure conduit connecting the pump outlet port with the first pressure control chamber, and a pressure control valve. The pressure control valve comprises an outlet port, a control valve cylinder wall comprising a control port connected with the outlet port, a control plunger which opens and closes the control port, an input pressure plunger connected with the control plunger, and a control spring preloading the control plunger into a closed position. The preload control arrangement comprises a preload cylinder, a preload plunger in the preload cylinder supporting a basis of the control spring, a preload cylinder inlet, and a preload control valve controlling a lubricant pressure.