Dual Pump Hydraulic System Power Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current hydraulically controlled transmission systems use a single mechanically driven pump that delivers fluid at the highest pressure required by any subsystem, leading to excessive power loss due to unnecessary high flow and pressure, and lack the ability for the lower pressure pump to assist the higher pressure pump.
Innovation Solution
A dual pump hydraulic system with a first electrically driven pump for high-pressure transmission control and a second mechanically driven pump for lubrication and cooling, where valves allow fluid flow from the lower pressure pump to assist the higher pressure pump when necessary, enabling electronic control for optimized flow and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single mechanically driven pump is used to supply hydraulic fluid to all subsystems, then the system can provide adequate pressure and flow to the highest pressure subsystem, but excessive power loss occurs due to pumping at higher flow and pressure than necessary for lower pressure subsystems
Solution Approach 1:
The hydraulic system is segmented into multiple independent pump circuits, each dedicated to specific subsystems with similar pressure requirements. The first pump serves high-pressure subsystems (transmission control, IVT hydros) while the second pump serves lower-pressure subsystems (clutches, lubrication, cooling), eliminating the energy waste of using a single high-pressure pump for all applications.
Solution Approach 2:
The system dynamically adapts pump operation through electronic control of the first pump's motor speed and solenoid valve actuation. The control system monitors subsystem pressure and flow requirements, adjusting the first pump's output dynamically to match actual demands, thereby reducing energy consumption when full pump capacity is not needed.
2Loss of energy
If a mechanically driven pump provides flow proportional to engine speed, then the pump is simple to operate, but the flow rate does not match the actual flow required by subsystems, causing excessive power loss
Solution Approach 1:
The first pump replaces pure mechanical engine-driven operation with an electrically controlled motor-driven system. This substitution enables electronic speed control of the pump motor, allowing the flow rate to be precisely matched to subsystem requirements rather than being passively proportional to engine speed, thereby reducing energy waste.
Solution Approach 2:
The system incorporates pressure sensors and solenoid valves that provide feedback to the pump control system. Based on real-time pressure readings from various subsystems, the control system adjusts the first pump's motor speed and flow output to match actual demands, eliminating the mismatch between supplied and required flow that causes power loss.
3Productivity
If the lower pressure pump cannot flow into the higher pressure circuit, then the pressure systems remain independent, but the system cannot utilize the lower pressure pump to assist the higher pressure pump during high demand conditions
Solution Approach 1:
The system dynamically controls the interconnection between pump circuits using solenoid valves that respond to pressure differential signals. When the first pump experiences high demand and its outlet pressure drops below a threshold, the solenoid valve automatically opens to allow the second pump to supply flow to the first circuit, providing dynamic assistance without requiring complex manual control or constant monitoring.
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 system reduces power loss by providing only the required flow and pressure, allows the lower pressure pump to assist the higher pressure pump, and maintains adequate performance at cold oil startup conditions, resulting in lower parasitic losses and improved efficiency.
Implementation Method 1
The second valve is connected to the first circuit via a check valve which prevents fluid flow from the first circuit to the second valve
Implementation Method 2
a first pump which supplies hydraulic fluid to the first subsystem at a first pressure
Implementation Method 3
a second pump which supplies hydraulic fluid to the second subsystem at a second pressure
Data Source
AI summary
A dual pump hydraulic system is provided for a vehicle driven by an internal combustion engine. The system includes a first circuit with a first high pressure pump supplying hydraulic fluid to the first subsystem at a higher pressure. The system also includes a second circuit with a second lower pressure pump supplying hydraulic fluid to the second subsystem at a second pressure. A first valve controls communication between the first pump and the second circuit. A second valve is operable to communicate the second pump with the first circuit when pressure in the first circuit is less than a second threshold pressure or when commanded by a control unit. A check valve prevents fluid flow from the first circuit back into to the second valve.