Hydraulic Circuit Drain Loop Cooling and Filtration
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Solution Overview
Problem
Existing hydraulic circuits for hybrid motor vehicles face issues with heat management and contamination, leading to increased size, mass, and cost due to the need for large heat exchangers and filters, as well as internal contamination causing faster aging and potential failures.
Innovation Solution
A hydraulic circuit with a drain loop that allows internal leakage to flow to a low-pressure accumulator or reservoir, incorporating a heat exchanger and filter in the drain loop, and using a motorized pump to control the flow rate for cooling and filtration, independent of the main power flow, thereby reducing component size and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a large heat exchanger is arranged along the main flow to limit pressure drop, then cooling efficiency is improved, but device size and mass increase
Solution Approach 1:
The hydraulic circuit is divided into a main power flow circuit and a separate drain circuit. The heat exchanger is placed only in the drain circuit, which handles a small portion of the total fluid flow. This segmentation allows the heat exchanger to be much smaller while still providing adequate cooling, since it only needs to handle the drain flow rather than the full main flow.
Solution Approach 2:
The drain circuit acts as an intermediary pathway that carries a small controlled flow from the hydraulic machines through the heat exchanger and filter back to the reservoir. This intermediary drain flow serves as a mediator that provides cooling and filtration functions without requiring the main power flow to pass through large components.
2Reliability
If a large filter is provided in the main flow to avoid great pressure drop, then filtration efficiency is improved, but device size and cost increase
Solution Approach 1:
The filtration function is separated from the main power flow and placed in the drain circuit. The filter only needs to handle the small drain flow, allowing it to be much smaller and lighter while still providing effective filtration. The drain flow carries contaminants away from the hydraulic machines, and the filter captures these contaminants in the drain circuit rather than in the main flow path.
3Reliability
If a single direction filter is used in the main flow, then filtration is provided, but additional components are needed to handle bidirectional flow, increasing device complexity
Solution Approach 1:
Instead of placing the filter in the main power flow where bidirectional flow requires complex valve arrangements, the filter is placed in the drain circuit where flow is naturally unidirectional. The drain flow always moves from the hydraulic machines through the filter and heat exchanger back to the reservoir, regardless of the direction of main power flow. This inversion of where filtration occurs eliminates the need for additional valves and complex arrangements.
4Productivity
If internal leakage is not controlled, then hydraulic machines can operate, but contamination accumulates and causes faster aging and failures
Solution Approach 1:
The drain circuit extracts internal leakage flow from the hydraulic machines and directs it through the filter and heat exchanger back to the reservoir. This extraction process removes contaminants and heat that would otherwise accumulate in the system. The controlled drain flow continuously scavenges the hydraulic machines, preventing contamination buildup and extending service life while maintaining operational capability.
Solution Approach 2:
The hydraulic machines' own internal leakage, which is normally wasted fluid, is put to useful effect by routing it through the filter and heat exchanger. The drain circuit uses the machines' inherent leakage flow as the medium for filtration and cooling, turning a potentially harmful byproduct into a beneficial self-cleaning and self-cooling mechanism.
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 enables efficient cooling and filtration of the entire hydraulic circuit with a minimal number of components, reducing energy consumption and extending the lifespan of hydraulic machines while minimizing pressure drop and component size.
Implementation Method 1
the outlet pipe having a heat exchanger and a filter located therealong which form the fluid processing elements for the entire hydraulic circuit
Implementation Method 2
the outlet pipe having a heat exchanger and a filter located therealong which form the fluid processing elements for the entire hydraulic circuit
Data Source
AI summary
The invention relates to a hydraulic circuit provided with at least one hydraulic power machine (2, 4) connected to a low-pressure circuit (6) and to a high-pressure circuit (10) transmitting said power, wherein the machine is provided with a drain which allows internal leaks in the casing thereof to flow towards a low-pressure accumulator (8) or a vessel at atmospheric pressure, said circuit comprising an intake pipe (30) connecting the low-pressure circuit (6) to the casing of the machine, and an outlet pipe (36) forming the drain receiving the flow from the intake pipe in order to guide same towards the vessel (8), including a heat exchanger (42) and a filter (44) forming the fluid treatment elements for the entire hydraulic circuit, said circuit also comprising a means for monitoring the flow (40) in the intake and outlet pipes.