Hydraulic Circuit Control for Stable Tool Operation in Work Vehicles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydraulic systems in work vehicles face inefficiencies due to the direct proportional relationship between prime mover rotation speed and vehicle speed, affecting hydraulic actuator performance and requiring separate control of the accelerator and joystick levers, which complicates operation and productivity.
Innovation Solution
A method where the joystick lever controls prime mover speed and hydraulic actuator operation independently, with distinct bands for proportional adjustment and compensation, allowing separate control of hydrostat transmission ratio to maintain consistent vehicle speed despite prime mover variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the prime mover rotation speed is increased to improve vehicle speed, then vehicle speed increases, but hydraulic actuator control becomes unstable and productivity decreases
Solution Approach 1:
The control system is segmented into two independent control paths: one path controls vehicle speed through the accelerator lever and hydrostat, while the other path controls hydraulic actuators through the joystick lever. This segmentation allows each control function to operate independently without interference, resolving the contradiction between vehicle speed and hydraulic actuator stability.
2Speed
If the accelerator lever controls both vehicle speed and prime mover speed, then vehicle speed regulation is achieved, but hydraulic actuator control precision deteriorates
Solution Approach 1:
The control functions are segmented and assigned to separate control devices: the accelerator lever exclusively controls vehicle speed via the hydrostat, while the joystick lever exclusively controls hydraulic actuators. This eliminates the conflict between dual control functions and ensures high precision for both control tasks.
Solution Approach 2:
The processing unit acts as an intermediary that receives signals from both the accelerator lever and joystick lever, then independently processes these signals to control the hydrostat and hydraulic valves respectively. This intermediary processing ensures that each control signal is handled with appropriate precision without interference from the other control function.
3Ease of operation
If separate control of accelerator and joystick levers is maintained, then vehicle speed and hydraulic actuator control are independent, but system complexity increases
Solution Approach 1:
The processing unit serves multiple functions: it processes accelerator lever signals for vehicle speed control, processes joystick lever signals for hydraulic actuator control, and coordinates both control paths. This multi-functionality consolidates the control system architecture, reducing overall complexity despite the independent control requirements.
4Measurement precision
If the joystick lever controls only hydraulic actuators, then actuator control precision improves, but prime mover speed regulation capability is lost
Solution Approach 1:
The control responsibilities are segmented: the accelerator lever is assigned to control prime mover speed and vehicle speed, while the joystick lever is assigned to control hydraulic actuators. This segmentation ensures that each control device operates within its designated function with optimal precision and capability.
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
Enhances productivity by allowing precise control of hydraulic actuators and vehicle speed, reducing hydraulic oil flow losses and compensating for prime mover speed changes, thus optimizing overall system performance.
Implementation Method 1
The hydraulic circuit is powered by a first hydraulic pump driven in rotation by a prime mover
Implementation Method 2
The lifting and lowering of the arm and the rollback and unload of the bucket or forks are carried out using at least one double-action hydraulic actuator
Implementation Method 3
the transmission to transfer the motion of the prime mover to the wheels is hydraulic
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Method for managing a hydraulic circuit (HC) of a work vehicle, comprising a first operating mode, called "accelerator-base", in which a rotation speed (ES) of the prime mover (E) is directly proportional to a deflection of an accelerator lever (AP) and in which a speed (VS) of the vehicle and the rotation speed of the prime mover are approximately directly proportional to each other and a second operating mode, called "tool-base", in which in a first continuous range of joystick lever deflection (LJK), the prime mover is operated at a predetermined approximately fixed rotational speed, and an opening of the open-center directional valve is proportional to the deflection of the joystick lever (LJK), in a second continuous joystick lever deflection (LJK) range distinct and separate from said first deflection range, the prime mover is operated at a rotational speed proportional to said joystick lever deflection (LJK) and the open center directional valve opening is fixed at a maximum opening value.