Hydraulic Pump Stand-By Pressure Control for Easier Engine Start-Up
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Solution Overview
Problem
Existing pressurized fluid supply systems in mobile machines, particularly tractors, face challenges during engine start-up due to increased load from hydraulic pumps, especially in cold weather, and electronic load sensing systems can introduce erroneous load demands, prolonging engine start-up times and increasing power demands.
Innovation Solution
A mobile machine with a hydraulic supply system that inhibits electronic load sensing functionality during engine start-up, setting a lower hydro-mechanically defined stand-by pressure differential, and only activates electronic load sensing once the engine is running, ensuring correct operation without erroneous load demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electronic load sensing functionality is active during engine start-up, then the hydraulic system can respond to load demands, but the engine start-up time is prolonged and power demand increases due to erroneous load sensing signals
Solution Approach 1:
The patent extracts and removes the electronic load sensing functionality from the system during engine start-up. The controller selectively disables the electronic load sensing circuitry when it detects that the engine is not yet running, preventing erroneous load signals from being generated. This extraction of the problematic component during the critical start-up phase resolves the contradiction by eliminating the source of erroneous signals while maintaining the ability to re-enable the functionality once the engine is running.
Solution Approach 2:
The patent implements dynamic control of the electronic load sensing functionality based on engine running status. The controller continuously monitors whether the engine is running and dynamically switches the electronic load sensing functionality between enabled and disabled states. This dynamic adaptation allows the system to optimize performance by preventing erroneous signals during start-up while maintaining full functionality during normal operation, thereby resolving the time loss issue without sacrificing hydraulic responsiveness when needed.
2Reliability
If hydraulic pump maintains normal stand-by pressure differential during engine start-up, then the hydraulic system is ready for operation, but the engine load increases making start-up difficult
Solution Approach 1:
The patent changes the pressure differential parameter during engine start-up by disabling the electronic load sensing functionality. Normally, the electronic load sensing maintains a stand-by pressure differential to ensure hydraulic system readiness. However, during engine start-up, the controller detects the non-running state and disables the electronic load sensing, which reduces the pressure differential demand on the hydraulic pump. This parameter change lowers the power demand on the engine during the critical start-up phase while allowing the system to return to normal pressure parameters once the engine is running.
3Productivity
If electronic load sensing is disabled during engine start-up, then engine start-up is facilitated, but the hydraulic system cannot respond to load demands during this period
Solution Approach 1:
The patent implements periodic action by temporarily disabling the electronic load sensing functionality only during the specific period of engine start-up, rather than permanently disabling it. The controller continuously monitors engine running status and switches the electronic load sensing between disabled (during start-up) and enabled (during normal operation) states. This periodic enable/disable pattern allows the system to optimize for fast engine start-up when needed while maintaining full hydraulic responsiveness during normal operation, thus resolving the contradiction between start-up speed and system responsiveness.
Data Source
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AI summary
Mobile Machine with Hydraulic Supply System A mobile machine such as a tractor (60) has an engine (60A) and hydraulic supply system (64) including a pump supply (66) with a pump (MP) driven by the engine to provide a pressurised fluid at a pump supply pressure PSP. The hydraulic supply system has an electronic load sensing system (E-LS) (100) to regulate the pump supply pressure. The E-LS is arranged to increase a stand-by pressure differential of the pump supply once the engine is determined to be running following start-up. This enables the hydraulic supply system to be configured with a reduced hydro-mechanically defined stand-by pressure differential so that it places a reduced load on the engine when it is started. The E-LS may be arranged to inhibit LS control of the pump supply when the engine is started, with LS functionality only commenced once the engine is running. Reduced load on the engine during start-up can improve cold starting.