Transmission Hydraulic Control Unit With Constant Torus Flow
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Solution Overview
Problem
The flow rate through the torque converter lock-up clutch in automatic transmissions is dependent on pressure and orifice diameter, leading to increased oil demand and fuel consumption, as well as potential power transmission capacity issues due to pressure peaks and drops.
Innovation Solution
A volumetric flow rate control valve is introduced to set a constant flow rate by controlling a defined pressure differential across an orifice, independent of inlet and outlet pressures, reducing the flow through the torque converter torus and allowing for a smaller oil pump without compromising shift quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the oil pump is designed to be large to meet high oil demand during high pressure at the torque converter lock-up clutch, then enough oil is available to the system, but fuel consumption increases
Solution Approach 1:
The patent introduces a dynamically adjustable flow control valve in the torus oil line that can vary the flow rate based on operating conditions. This allows the system to maintain adequate oil flow to the torque converter lock-up clutch while reducing overall oil pump output during conditions that don't require maximum flow, thereby reducing fuel consumption without compromising oil availability when needed.
Solution Approach 2:
The patent changes the flow rate parameter dynamically by using a flow control valve with adjustable opening. This allows the system to optimize the balance between oil availability to the torque converter and overall oil consumption by the pump, enabling smaller pump designs that consume less fuel while still meeting peak demand requirements.
2Temperature
If a large flow rate through the torus is allowed to cool the torque converter lock-up clutch, then cooling is sufficient, but the primary system pressure circuit demand increases
Solution Approach 1:
The patent applies local quality control by positioning a flow control valve specifically in the torus oil line that supplies the torque converter lock-up clutch. This allows differential flow control - maintaining adequate cooling flow to the clutch while potentially restricting flow in other circuits. The valve enables localized optimization of cooling effectiveness without unnecessarily increasing overall system oil demand.
3Reliability
If pressure peaks or pressure drops in the torus occur, then power transmission capacity of the torque converter lock-up clutch is affected, but flow control through the torus is necessary
Solution Approach 1:
The patent implements feedback control through a flow control valve that responds to pressure conditions in the torus. The valve mechanism senses pressure variations and automatically adjusts flow rate to maintain stable pressure conditions, preventing both pressure peaks and drops that would affect power transmission capacity. This feedback-based approach provides reliable power transmission without requiring complex external control systems.
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 solution reduces the size of the mechanical pump, decreases oil demand, and maintains consistent power transmission capacity by ensuring constant flow to the torque converter lock-up clutch, minimizing pressure fluctuations and fuel consumption.
Implementation Method 1
A volumetric flow rate control valve is introduced to set a constant flow rate by controlling a defined pressure differential across an orifice
Implementation Method 2
The flow rate at the torus is therefore dependent on the pressure at the torque converter lock-up clutch and on the diameter of the torus orifice
Data Source
AI summary
A hydraulic control unit (4) for an automatic transmission of a motor vehicle includes a volumetric flow rate control valve (49). The hydraulic control unit (4) is configured for delivering hydraulic fluid to an inlet (59) of the volumetric flow rate control valve (49). An outlet (31, 71) of the volumetric flow rate control valve (18, 49) is connected to a torque converter torus of the automatic transmission. In addition, the volumetric flow rate control valve (59) is configured for directing the hydraulic fluid across an orifice (66), so that the pressure of the hydraulic fluid is reduced and a constant flow of hydraulic fluid is feedable to a torque converter torus.