Hydraulic Assistance System with Variable Displacement Pump
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Solution Overview
Problem
Existing hydraulic assistance systems for motor vehicles are inflexible and limited in their pressure range, requiring a booster pump and a valve to manage circuit pressure, which restricts torque control and flexibility.
Innovation Solution
A hydraulic assistance system with a primary motor and two hydraulic machines connected in an open circuit through a reservoir, featuring a variable displacement pump controlled by a proportional calibration pressure limiter and a collection restriction, along with opposing actuators and a control module to maintain set pressure, allowing for flexible pressure control and a wide range of torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed-displacement pump with pressure limiter is used, then the circuit pressure can be maintained constant, but the system becomes inflexible and limited in pressure range
Solution Approach 1:
The patent applies a variable displacement pump instead of a fixed-displacement pump, allowing the pump's displacement to be dynamically adjusted based on pressure feedback. This enables the system to adapt to different pressure requirements while maintaining stable pressure control, resolving the contradiction between reliability and adaptability.
Solution Approach 2:
The patent changes the key parameter of pump displacement from fixed to variable, controlled by a feedback mechanism that adjusts displacement based on actual pressure conditions. This parameter change enables both stable pressure maintenance and flexible adaptation to different pressure ranges.
2Reliability
If a booster pump and valve are used to manage circuit pressure, then pressure control is achieved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the booster pump from the system by using a variable displacement pump that can directly control pressure through feedback. This reduces device complexity while maintaining pressure control capability through a more efficient single-pump architecture.
Solution Approach 2:
The patent implements a pressure feedback control mechanism where the actual pressure is monitored and used to adjust the pump's displacement in real-time. This feedback loop enables precise pressure control without requiring additional complex components like booster pumps and pressure management valves.
3Productivity
If a closed circuit is used with hydraulic machines, then assistance is provided, but a valve is required to open the circuit for starting and deactivating motors
Solution Approach 1:
The patent uses a variable displacement pump that can dynamically adjust its operation, eliminating the need for mechanical valves to open/close the circuit. The pump can be deactivated or adjusted to minimal displacement to stop assistance, reducing component complexity while maintaining productivity.
Solution Approach 2:
The patent replaces the mechanical valve system required for circuit opening with a controllable variable displacement pump system. The pump's displacement control mechanism substitutes for the valve function, eliminating the need for separate valve components while maintaining the ability to start and deactivate motors.
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 provides constant pressure control via a closed-loop feedback circuit, enabling flexible pressure management and a broad range of torque, eliminating the need for a booster pump and enhancing system flexibility.
Implementation Method 1
the variable displacement whereof is controlled in pressure by means of a device comprising a proportional calibration pressure limiter
Implementation Method 2
a hydraulic assistance system for a motor vehicle, comprising a primary motor and two hydraulic machines connected by a hydraulic circuit
Data Source
AI summary
The present invention relates to a hydraulic-assistance system for motor vehicles, comprising a primary motor (M) and two hydraulic machines (140; 240, 250) connected by a hydraulic circuit such that when a first hydraulic machine (140) operates as a pump, the second hydraulic machine (240, 250) operates as a motor. The invention is characterized in that the hydraulic circuit connecting the two machines (140; 240, 250) is an open circuit passing through a tank (300), the hydraulic machine (240, 250) operating as a motor is a declutchable machine, and the hydraulic machine (140) operating as a pump is a pump in which the variable displacement is controlled by a device comprising a proportional pressure limiter (470) placed between a drain line (143) and the discharge line of the hydraulic machine (140) operating as a pump, and enabling the assistance pressure to be set, and at least one collection nozzle (460) placed between the proportional pressure limiter (470) and the discharge line of the hydraulic machine (140), the setpoint pressure controlling the hydraulic machine (140) operating as a pump being collected between the pressure limiter (470) and the collection nozzle (460).