Variable Displacement Oil Pump Control for Engine Noise Reduction
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Solution Overview
Problem
Conventional oil supply systems for engines experience increased engine noise during low load operations, such as idle, due to insufficient lubricating oil films on drive force transmission system members, which results from reduced oil mist generation when the engine load is low.
Innovation Solution
An oil supply system that includes an oil pressure controller to adjust the discharge pressure of a variable displacement oil pump, a load detector to monitor engine load, and an oil temperature detector to increase oil mist generation inside the crankcase when the engine load is low, ensuring adequate lubrication of sliding surfaces even during low load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the discharge amount of the variable displacement oil pump is reduced to suppress drive force and improve fuel consumption, then fuel consumption is improved, but the generation amount of oil mist is reduced causing insufficient atmospheric lubrication and increased engine noise
Solution Approach 1:
The control method changes the operating parameters of the oil pump based on engine conditions. Specifically, it monitors engine load and oil temperature, and adjusts the oil pump's discharge amount accordingly. When engine load is below a predetermined threshold and oil temperature is below another threshold, the control method increases the discharge amount to generate sufficient oil mist for atmospheric lubrication, thereby reducing engine noise while maintaining fuel efficiency during normal operation
Solution Approach 2:
The control method implements a feedback mechanism by continuously monitoring engine load and oil temperature through detectors. Based on this feedback information, the control method dynamically adjusts the oil pump's discharge amount to maintain optimal atmospheric lubrication conditions. This closed-loop control ensures that oil mist generation is sufficient to reduce engine noise during idle and low-load operations
2Power
If the discharge amount of the variable displacement oil pump is reduced to achieve required oil pressure with minimum drive force, then the drive force is suppressed to necessary minimum level, but the formation of lubricating oil films on sliding surfaces becomes insufficient causing increased engine noise
Solution Approach 1:
The control method dynamically changes the discharge amount parameter of the oil pump based on engine operating conditions. During idle and low-load operations, when engine load is below a predetermined threshold, the method increases the discharge amount to generate sufficient oil mist for atmospheric lubrication, thereby reducing engine noise while maintaining minimal drive force during normal operation
Solution Approach 2:
The control method makes the oil pump's discharge amount dynamic rather than fixed. It continuously adapts the discharge amount based on real-time engine load and oil temperature conditions, increasing discharge during idle/low-load operations to ensure adequate atmospheric lubrication and reducing discharge during normal operation to minimize drive force consumption
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 system effectively reduces engine noise by maintaining sufficient lubricating oil films on drive force transmission system members, even during low load operations, by increasing oil mist generation, thereby acting as a cushion and minimizing noise.
Implementation Method 1
oil leaked from, for example, a bearing metal of a crankshaft bearing rotatably supporting a crankshaft is spread and atomized (becomes a mist) by rotation of the crankshaft
Implementation Method 2
The oil mist permeates and attaches to the sliding surfaces of the drive force transmission system members and lubricating oil films are formed thereon
Data Source
AI summary
An oil supply system for an engine is provided, which includes an oil pressure controller for controlling a variable displacement oil pump to adjust a discharge pressure thereof to reach a target oil pressure corresponding to an operating state of the engine, the variable displacement oil pump capable of adjusting a discharge amount of oil, a load detector for detecting an engine load, and an oil temperature detector for detecting an oil temperature. When the engine load is low, to increase an amount of oil mist flowing inside a crank case of the engine, the oil pressure controller controls the variable displacement oil pump to increase the discharge amount as the oil temperature becomes lower, the oil mist generated by the oil flowing out of a bearing part rotatably supporting at least a crankshaft and being atomized, the engine load being considered low when below a predetermined reference load.