Electrohydraulic Steering Pump Pre-Pressure for Power-On-Demand
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulic power steering systems in heavy utility vehicles rely on a continuously operating hydraulic pump driven by an internal combustion engine, leading to unnecessary energy consumption and heating of the steering system, which is inefficient and not suitable for vehicles without an internal combustion engine or for automated driving applications.
Innovation Solution
A pump apparatus and electrohydraulic power steering system that includes a hydraulic pump, pressure generation device, control lines, and a shut-off valve, allowing for pre-pressure generation and operation independent of the internal combustion engine, with a 'power on demand' principle, using a dual piston to adjust pressure and a shut-off valve to manage hydraulic oil flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the hydraulic pump is permanently driven by the internal combustion engine to continuously circulate hydraulic oil, then the hydraulic system is sufficiently controlled in terms of temperature and the block steering system is permanently heated, but energy consumption increases and the system is not suitable for vehicles without internal combustion engines
Solution Approach 1:
The patent implements periodic action by operating the hydraulic pump only when steering input is detected rather than continuously. The control unit activates the pump intermittently based on steering wheel angle sensor signals, achieving temperature control through periodic operation while dramatically reducing energy consumption compared to permanent operation
Solution Approach 2:
The system uses the vehicle's existing electric power steering motor to drive the hydraulic pump when needed, rather than requiring a separate engine-driven pump. The electric motor serves dual purposes: providing steering assistance and powering the hydraulic system, enabling the system to serve itself without additional energy sources
2Reliability
If the hydraulic pump operates continuously to maintain system pressure, then the steering system remains ready for operation, but energy is wasted during periods when no steering is required
Solution Approach 1:
The system builds up hydraulic pressure in advance when steering input is detected, rather than maintaining constant pressure. The control unit activates the pump before steering assistance is needed, pre-charging the hydraulic system so that when steering is required, pressure is already available, eliminating the need for continuous operation
Solution Approach 2:
The system dynamically adjusts pump operation based on real-time steering conditions. The control unit continuously monitors steering wheel angle and activates the pump only when steering input exceeds threshold values, creating a dynamic operation mode that adapts to actual steering needs rather than maintaining static continuous operation
3Stress or pressure
If a pre-pressure generation system is implemented with pressure generation device and shut-off valve, then the pump chamber can be pressurized independently of the pump operation, but the device complexity increases
Solution Approach 1:
The pressure generation device serves multiple functions: it pressurizes the pump chamber independently, maintains pre-pressure during pump idle periods, and works cooperatively with the main hydraulic system. The shut-off valve integrates into the existing hydraulic circuitry to control pressure distribution, allowing one component to perform multiple roles and reducing overall system complexity despite the added functionality
Solution Approach 2:
The pressure generation device acts as an intermediary between the electric motor and the hydraulic system. It receives mechanical input from the motor and converts it to hydraulic pressure in the pump chamber, mediating the energy transfer and enabling independent pressurization without requiring direct pump operation
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
Enables efficient hydraulic power steering in vehicles without an internal combustion engine, supporting automated driving and reducing energy consumption by operating the hydraulic pump only when needed, with the system maintaining hydraulic oil pressure for temperature compensation.
Implementation Method 1
The hydraulic pump (110) is constructed to pump a hydraulic oil (155) from a pump chamber (160) to a pump output (165)
Implementation Method 2
The pressure generation device (120) is constructed, using an input pressure which is applied at the pressure generation input (180), to produce an output pressure which can be provided at the pressure generation output (185) and which is lower than the input pressure
Implementation Method 3
The shut-off valve (140) is constructed, depending on a pressure applied at the control input (145) of the shut-off valve (140), to assume a valve open position or a valve closed position
Data Source
AI summary
A pump apparatus for an electrohydraulic power steering mechanism for a vehicle includes a hydraulic pump, a working line, a pressure generator, a first control line, a preliminary pressure line, a compensation tank, a shut-off valve having a control inlet, and a second control line. The hydraulic pump is designed to pump a hydraulic oil out of a pump chamber to a pump outlet of the hydraulic pump. The pressure generator has a pressure generation inlet and a pressure generation outlet, and the pressure generator is designed to generate, using an inlet pressure present at the pressure generation inlet, an outlet pressure which can be provided at the pressure generation outlet and is lower than the inlet pressure. As a result, a preliminary pressure can be generated in the pump chamber.