Hydraulic Pump Feedback Valve for Lower Cold-Start Load
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Solution Overview
Problem
Commercial vehicles face high power requirements for hydraulic adjustment pumps during starting, especially in cold conditions where hydraulic medium viscosity increases, leading to increased power consumption.
Innovation Solution
A hydraulic arrangement with a valve device that reduces the output pressure and volume flow of the adjustment pump during starting, using a valve unit that acts as a hydraulic interruption between the feedback connection and the adjustment control, thereby minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the variable displacement pump is set to maximum delivery position during engine start-up, then the hydraulic consumers receive sufficient hydraulic flow, but the power consumption of the pump increases significantly
Solution Approach 1:
The pump control is made dynamic by introducing a starting mode that automatically adjusts the pump control position based on engine operating conditions. During engine start-up, the control position is dynamically adjusted to a starting position (lower than maximum) to reduce power consumption, while during normal operation it returns to maximum delivery position to ensure hydraulic supply reliability.
Solution Approach 2:
The invention changes the control parameter (pump control position) based on engine operating conditions. By detecting engine start-up conditions and adjusting the pump control position accordingly, the system optimizes the balance between hydraulic supply and power consumption. The control position is changed from maximum delivery to a reduced starting position during engine start-up.
2Reliability
If the hydraulic fluid viscosity increases during cold start, then the hydraulic medium becomes harder to pump, but the power consumption of the variable displacement pump increases further
Solution Approach 1:
The system dynamically adapts to cold start conditions by detecting the engine start-up state and automatically adjusting the pump control to a starting position. This dynamic adjustment reduces the pump's power consumption during cold starts when hydraulic fluid viscosity is high, making the system more operable during difficult starting conditions.
Solution Approach 2:
The invention applies preliminary anti-action by proactively reducing the pump control position before the high viscosity of cold hydraulic fluid can cause excessive power consumption. The starting mode is activated during engine start-up to preemptively counteract the adverse effects of high viscosity, reducing the load on the starter motor and drive motor.
3Reliability
If the variable displacement pump consumes high power during starting, then the hydraulic system is ready for operation, but the starter motor and drive motor are overloaded
Solution Approach 1:
The pump control position is dynamically adjusted based on engine operating conditions. During engine start-up, the control position is set to a starting position that reduces power consumption and motor load, while still providing sufficient hydraulic flow for system readiness. During normal operation, the control returns to maximum delivery position.
Solution Approach 2:
The invention changes the pump control parameter based on engine operating conditions. By detecting engine start-up and adjusting the control position to a starting position, the system reduces the power demand on the starter motor and drive motor, preventing overload while maintaining hydraulic system readiness.
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
The solution reduces the power required for the drive engine and adjustment pump during starting, alleviating energy losses and facilitating a successful cold start with lower power requirements.
Implementation Method 1
A hydraulic arrangement (42) with a variable displacement pump (46), having a pump outlet (54) and a feedback connection (50). The variable displacement pump (46) is adjustable with regard to its delivery rate or volume flow by an adjustment control (64) which is dependent on an output pressure (pa) of the variable displacement pump (46), a signal pressure of the feedback connection (50) and optionally on one or more further physical variables. A valve device (80) is provided in a flow path between the feedback connection (50) and the adjustment control (64).
Data Source
Figure 1
Figure 2~3
Figure 4A~4D
AI summary
The invention relates to a hydraulic arrangement (42) for a commercial vehicle (10) with a supply port (48) hydraulically connected or connectable to a pump outlet (54) of a hydraulic variable displacement pump (46) and with a feedback port (50). Furthermore, an adjustment control (64) for adjusting the variable displacement pump (46) is provided, the adjustment of which depends on an outlet pressure (p_a) of the variable displacement pump (46) and on a signal pressure (p_m) of the feedback port (50). A hydraulic valve device (80) is arranged in the flow path between the feedback port (50) and the adjustment control (64). The valve device (80) includes a valve unit (82) which, depending on a switching position, acts as a hydraulic connection or interruption in the flow path. The invention also relates to a commercial vehicle (10) with such a hydraulic arrangement (42).