Hydraulic Start Clutch Lubrication Control for Lower Oil Stirring Loss
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Solution Overview
Problem
The existing hydraulically operated transmission systems require complex control structures to regulate lubricant oil supply to frictional coupling elements, leading to increased energy loss and reduced fuel efficiency due to excessive lubricant oil stirring by rotating members.
Innovation Solution
A hydraulically operated transmission system with a pressure regulator and a lubrication control valve that adjusts lubricant oil flow based on hydraulic pressure, supplying more oil when the coupling element is slipping and reducing it when fully coupled, using parallel orifices to manage oil flow efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of lubricant oil is supplied constantly to the start clutch to ensure reliability during slipping, then the reliability of the start clutch is improved, but the fuel efficiency drops due to increased energy loss from stirring the lubricant oil
Solution Approach 1:
The lubrication control valve dynamically adjusts the lubricant oil flow rate based on the operating state of the start clutch. During slipping, the valve opens fully to provide maximum lubrication; during complete coupling, the valve reduces flow rate automatically. This dynamic adjustment resolves the contradiction by matching lubrication supply to actual needs rather than maintaining constant high flow.
Solution Approach 2:
The system changes the flow rate parameter of lubricant oil based on the pressure regulator's output pressure and the differential pressure across the lubrication control valve. By varying this parameter according to clutch state, the system ensures adequate lubrication during slipping while reducing energy loss during complete coupling.
2Loss of energy
If the amount of lubricant oil supplied to the start clutch is controlled by controlling both the reducing valve and the oil pump, then the lubrication efficiency is improved, but the structure and control become complicated
Solution Approach 1:
The lubrication control valve is designed to operate automatically based on the differential pressure between high pressure and regulated pressure. The valve self-regulates the lubricant oil flow rate without requiring external control signals or complex control systems, thereby improving lubrication efficiency while avoiding increased structural complexity.
Solution Approach 2:
The lubrication control valve acts as an intermediary device that automatically mediates between the pressure regulator and the start clutch. It uses the pressure differential as a control signal to adjust lubrication flow, eliminating the need for complex control systems while maintaining efficient lubrication.
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 configuration simplifies the structure for regulating lubricant oil supply, reducing energy loss and maintaining fuel efficiency by automatically adjusting lubricant oil flow according to the coupling state of the frictional element.
Implementation Method 1
a pressure regulator which regulates a pressure of a hydraulic oil supplied to the coupling hydraulic chamber... configured to gradually increase the pressure of the hydraulic oil from a low pressure lower than the first predetermined pressure to the first predetermined pressure, and then to a high pressure higher than the first predetermined pressure
Implementation Method 2
The lubrication control valve is configured to operate based on a differential pressure between the high pressure and a regulated pressure regulated by the pressure regulator
Data Source
AI summary
A hydraulically operated transmission includes: a pressure regulator which regulates pressure of a hydraulic oil supplied to a coupling hydraulic chamber of a frictional coupling element for starting a vehicle; and a lubrication control valve provided at a lubricant oil supplying circuit for supplying the lubricant oil to the frictional coupling element. The lubrication control valve operates, in coupling the frictional coupling element at start of the vehicle, such that the lubricant oil is supplied to the frictional coupling element at a greater flow rate when a regulated pressure regulated by the pressure regulator is lower than a second predetermined pressure, than when the regulated pressure is higher than or equal to the second predetermined pressure. The second predetermined pressure is set to be higher than or equal to a first predetermined pressure, at which the frictional coupling element is completely coupled, and to be lower than a high pressure.