Hydraulic Pump Conveying Capacity Determination Method
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Solution Overview
Problem
Hydraulic pumps in automatic transmissions convey excessive hydraulic fluid at high drive rotational speeds, leading to increased power losses and energy consumption, while attempts to reduce this through adjustable pumps result in under-supply states and impaired driving comfort due to production tolerances and wear.
Innovation Solution
A method to determine the conveying capacity of hydraulic pumps by connecting a blockable flow cross-section to the pressure side, allowing the entire volume flow to be guided through it, and comparing the resulting operating state changes to a reference, enabling adjustment to avoid under-supply and excessive power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant pump is designed to convey sufficient hydraulic fluid at low drive rotational speeds, then the transmission is supplied with adequate hydraulic fluid, but at high drive rotational speeds the pump conveys excessive volumes leading to increased power losses and energy consumption
Solution Approach 1:
The patent applies dynamics by making the pump's conveying capacity variable rather than constant. The control device adjusts the displacement volume of the pump based on actual transmission needs, allowing the system to adapt to different operational conditions. This resolves the contradiction by enabling the pump to convey sufficient fluid at low speeds while reducing conveyance at high speeds to minimize energy losses.
Solution Approach 2:
The patent changes the parameter of conveying capacity from fixed to variable. By adjusting the displacement volume parameter based on operational requirements, the system optimizes energy efficiency across different drive rotational speeds while maintaining adequate hydraulic supply when needed.
2Loss of energy
If the conveying capacity of the hydraulic pump is reduced to decrease power losses, then energy consumption decreases, but under-supply states occur due to production tolerances and wear
Solution Approach 1:
The patent implements feedback through a control device that monitors the actual conveying capacity of the pump and adjusts the displacement volume accordingly. This feedback mechanism compensates for variations caused by production tolerances and wear, ensuring adequate hydraulic supply while optimizing energy consumption. The system continuously adapts to maintain reliability without excessive energy use.
3Loss of energy
If adjustable hydraulic pumps are used with variable displacement volume, then energy consumption can be optimized, but production tolerances and wear cause actuating effort increases and control inaccuracy
Solution Approach 1:
The patent applies self-service by designing a control system that automatically compensates for production tolerances and wear without requiring complex external adjustments. The control device autonomously monitors and adjusts the pump's conveying capacity, reducing the need for manual intervention and simplifying overall system operation despite the variable displacement mechanism.
Data Source
AI summary
A method for determining a conveying capacity of a hydraulic pump includes opening a blockable flow cross-section in order to connect a pressure side of the hydraulic pump to an area of the hydraulic system through the flow cross-section after operating the hydraulic pump driven at a defined rotational speed. The flow cross-section is configured with the hydraulic pump such that an entire conveying volume flow provided by the hydraulic pump is guided through the flow cross-section when the flow cross-section is open. The method further includes comparing a change to an operating state of the transmission resulting from opening of the flow cross-section to a reference change to the operating state and determining the conveying capacity of the hydraulic pump as a function of a deviation between the change to the operating state and the reference change to the operating state.