Load-Controlled Hydraulic Pumping for Tractor Fuel Efficiency
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Solution Overview
Problem
Existing load-sensing hydraulic systems in agricultural vehicles face inefficiencies due to diesel engines operating in non-optimal power curves and excessive flow rates outside mid-range speeds, leading to increased fuel consumption and noise.
Innovation Solution
A load-controlled hydraulic supply system with an electric actuator and control unit that adjusts the variable displacement pump's volume flow based on load demand, using pressure sensors to optimize pump operation and prevent inefficient engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the variable displacement pump is dimensioned to supply all hydraulic consumers at mid-range engine speeds, then the hydraulic supply reliability is improved, but the fuel consumption and noise increase due to excessive flow rates outside this speed range
Solution Approach 1:
The pump's delivery volume is made dynamically adjustable through an electronically controlled displacement control valve, allowing the system to adapt the flow rate to actual hydraulic consumer demands rather than maintaining a fixed high-capacity configuration for all operating conditions
Solution Approach 2:
The system changes the pump's operational parameters (delivery volume, flow rate) based on engine speed and actual hydraulic demand, using electronic control to modify the displacement control valve position and thereby optimize the pump's output across different operating ranges
2Productivity
If the variable displacement pump is dimensioned for high flow capacity, then the hydraulic supply capability is improved, but the diesel engine operates in inefficient power curve regions
Solution Approach 1:
The system uses feedback from engine speed sensors and hydraulic pressure sensors to continuously monitor operating conditions and adjust the pump's delivery volume accordingly, ensuring the engine operates in efficient power ranges while meeting hydraulic demands
Solution Approach 2:
The pump transitions from a static high-capacity design to a dynamic system that continuously adjusts its delivery volume based on real-time feedback about engine speed and hydraulic consumer demands, optimizing the match between engine output and hydraulic requirements
3Device complexity
If a mechanical load-sensing system is used, then the hydraulic control is simple and reliable, but the system cannot account for other factors relevant for efficient pump operation
Solution Approach 1:
The system replaces purely mechanical load-sensing control with an electronically controlled displacement valve actuated by an electric motor, allowing integration of electronic sensors and control units that can process multiple input signals and implement complex control strategies while maintaining reliable hydraulic control
Solution Approach 2:
The electronic control system serves multiple functions: it monitors engine speed, detects hydraulic pressure, calculates optimal pump delivery based on multiple factors, and controls the displacement valve, thereby providing both simple reliability and comprehensive adaptability in one integrated system
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 system ensures efficient hydraulic delivery by maintaining optimal flow rates and preventing diesel engines from operating in inefficient power ranges, reducing fuel consumption and allowing for a more compact gearbox design.
Implementation Method 1
The determination of the consumer-side load requirement is carried out by means of a pressure sensor, which serves to detect a load signal pressure of a hydraulic consumer applied to a feedback line
Implementation Method 2
the variable displacement pump has an electric actuator for actuating the control valve
Implementation Method 3
a variable displacement pump supplied with hydraulic fluid from a hydraulic reservoir
Data Source
Figure 1
Figure 2
AI summary
Load-controlled hydraulic supply (12) for a commercial vehicle, in particular an agricultural tractor (10), comprising a variable displacement pump (16) supplied with hydraulic fluid from a hydraulic reservoir (14), wherein the variable displacement pump (16) has a mechanically actuated control valve (20) for changing a delivered volume flow rate (Qpump). Furthermore, an electric actuator (18) is provided for actuating the control valve (20), wherein a control unit (22) actuates the electric actuator (18) according to a determined load demand from the consumer.