Hydraulic Work Vehicle Speed Control Using Differential Pressure Feedback
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Solution Overview
Problem
Existing speed control methods for work vehicles lack precision in maintaining a predetermined target speed, particularly in response to differential pressure variations, leading to inefficiencies and potential stalling issues.
Innovation Solution
A speed control method that involves controlling a first hydraulic pump to supply hydraulic fluid to a first hydraulic motor, detecting differential pressure, and regulating either the pump pilot pressure or engine rotational speed to maintain a predetermined target speed, using a control circuitry system that adjusts the pilot pressure and engine speed based on the detected differential pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing speed control methods limit pilot pressure or engine speed, then vehicle speed can be restricted, but the precision in maintaining a predetermined target speed deteriorates due to lack of response to differential pressure variations
Solution Approach 1:
The patent implements feedback control by detecting the differential pressure between the hydraulic motor inlet and outlet and using this information to dynamically adjust the pilot pressure supplied to the hydraulic pump. This closed-loop feedback mechanism enables precise maintenance of target speed by continuously responding to actual operating conditions, resolving the contradiction between control precision and system complexity.
Solution Approach 2:
The patent replaces conventional mechanical speed control mechanisms with a hybrid control system that incorporates electronic sensors for differential pressure detection and electronic control units for pilot pressure regulation. This substitution of mechanical systems with sensor-based electronic control improves speed control precision while managing system complexity through integrated control architecture.
2Speed
If pilot pressure is limited to control vehicle speed, then speed can be restricted, but engine stalling may occur and operational efficiency deteriorates
Solution Approach 1:
The patent implements dynamic control of pilot pressure based on real-time differential pressure detection rather than static pressure limitation. The control system continuously adjusts pilot pressure levels according to actual hydraulic motor loading conditions, enabling smooth speed control that prevents engine stalling by maintaining adequate pressure margins while improving operational efficiency through optimized pressure management.
Solution Approach 2:
The patent changes the control parameter from fixed pilot pressure limitation to variable pilot pressure adjustment based on detected differential pressure. By dynamically modifying the pilot pressure parameter in response to actual operating conditions, the system achieves reliable speed control that prevents engine stalling while maintaining operational efficiency across varying load conditions.
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 method effectively maintains a consistent target speed for the work vehicle, improving operational efficiency and preventing engine stalling by dynamically adjusting hydraulic pressure and engine speed in response to differential pressure changes.
Implementation Method 1
controlling a first hydraulic pump to supply hydraulic fluid to a first hydraulic motor to drive a first traveling device
Implementation Method 2
a first hydraulic pressure sensor configured to detect a first hydraulic pressure in the first oil passage, a second hydraulic pressure sensor configured to detect a second hydraulic pressure in the second oil passage
Data Source
AI summary
A speed control method for a work vehicle includes controlling a first hydraulic pump to supply hydraulic fluid to a first hydraulic motor to drive a first traveling device provided on a vehicle body of the work vehicle and detecting a first differential pressure of the first hydraulic motor. The method includes regulating at least one of a first pump pilot pressure applied to a first pump pilot port of the first hydraulic pump and a rotational speed of an engine to drive the first hydraulic pump such that a vehicle speed is controlled to maintain a predetermined target speed in response to an absolute value of the first differential pressure.