Transmission Oil Filter Damping for Intermittent Pump Pressure Surges
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Solution Overview
Problem
In motor vehicles with automatic start/stop systems, the intermittent operation of electrically actuatable oil pumps leads to rapid pressure increases and oil volume flow surges, causing a significant increase in particle numbers in the oil volume flow, which existing filtration systems fail to effectively clean due to mobilization of particles deposited on the filter medium.
Innovation Solution
The pressure oil filter system incorporates means for damping pressure surges upstream of the oil filter, utilizing a slow-opening first pressure valve and a fast-opening second pressure valve in a bridging line to reduce pulse loading on the filter medium, ensuring effective filtration during intermittent pump operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If intermittent operation of the electric oil pump is used during start/stop operation, then the transmission oil pressure can be maintained timely and energy efficiency is improved, but pressure surges cause a substantial increase in particle numbers in the oil volume flow
Solution Approach 1:
A damping element is introduced into the pressure line upstream of the oil filter to cushion pressure surges before they reach the filter. This beforehand cushioning prevents the mobilization of particles that would otherwise be deposited on the filter medium during intermittent pump operation, thereby maintaining oil purity while allowing energy-efficient intermittent pump operation.
2Object-affected harmful factors
If a finer filter medium is used to counteract particle increase, then filtration effectiveness is improved, but pressure losses in the oil filter increase
Solution Approach 1:
The damping element provides beforehand cushioning of pressure surges, allowing the use of finer filter media without experiencing the mobilization of particles that would occur with undamped pressure surges. This enables effective fine filtration while avoiding excessive pressure losses, as the damping element prevents the filter medium from being subjected to abrupt pressure increases that would cause particle mobilization.
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 approach reduces the number of particles in the oil volume flow during intermittent operation, achieving lower oil purity classes and maintaining effective cleaning, even with complex mechatronics systems.
Implementation Method 1
means for damping pressure surges during intermittent operation of the oil pump are provided in the pressure line upstream of the first oil filter
Implementation Method 2
at least a first oil filter which is arranged at the pressure side of the oil pump in the pressure line
Data Source
AI summary
The invention relates to a pressure oil filter system for a hydraulic transmission, in particular for a motor vehicle transmission, comprising at least one oil pump which can be actuated as required and which has a pressure side and a suction side, a pressure line to a consumer and at least a first oil filter which is arranged at the pressure side of the oil pump in the pressure line, wherein means for damping pressure surges during intermittent operation of the oil pump are provided in the pressure line upstream of the first oil filter in the flow direction of the oil.