Electric Vehicle Hydraulic System Torque Speed Matching
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Solution Overview
Problem
Conventional electric vehicle driving systems face inefficiencies due to mismatched torque and rotational speed characteristics, leading to poor performance at low and high speeds, which limits their driving range and applicability to complex driving conditions.
Innovation Solution
A hydraulic system for electric vehicles is introduced, comprising parallel clutch driving circuits, internal and external pumps, check valves, pressure regulating valves, and lubricating oil passages, which allows for dynamic adjustment of torque and rotational speed to optimize motor efficiency across different driving conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a reducer with constant transmission ratio is used, then the torque transmission is improved at low speed, but the power consumption increases significantly at high speed
Solution Approach 1:
The patent applies a multi-speed transmission system that dynamically changes transmission ratios based on operating conditions. The system switches between different transmission ratios (first transmission ratio for low speed, second transmission ratio for high speed) to optimize both torque transmission and power consumption across different speed ranges, resolving the contradiction between maintaining high torque at low speed and reducing power consumption at high speed.
2Force
If a reducer with high transmission ratio is used, then the torque output is improved, but the acceleration performance deteriorates
Solution Approach 1:
The system dynamically selects transmission ratios based on acceleration requirements. When acceleration is needed, the system switches to a lower transmission ratio to allow faster rotational speed changes. When sustained torque is needed, it switches to a higher transmission ratio, thus resolving the contradiction between torque output and acceleration performance.
3Force
If the driving motor operates at low rotational speed, then the output torque is high, but the efficiency is low
Solution Approach 1:
The multi-speed transmission system allows the driving motor to operate at higher rotational speeds by providing appropriate gear reduction, thereby maintaining high efficiency while still delivering high torque through the transmission system. The system dynamically adjusts transmission ratios to keep the motor operating in its high-efficiency range across different driving conditions.
4Use of energy by moving object
If the driving motor operates at high rotational speed, then the efficiency is improved, but the output torque becomes too low
Solution Approach 1:
The transmission system compensates for the low torque at high rotational speeds by applying appropriate gear reduction ratios. When the motor operates at high speed for efficiency, the transmission system multiplies the torque through gear reduction, thus resolving the contradiction between maintaining high efficiency and delivering sufficient torque.
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 hydraulic system effectively matches torque and rotational speed characteristics, improving driving motor efficiency, reducing energy consumption, and increasing the driving range of electric vehicles by enabling better performance under various driving conditions.
Implementation Method 1
an internal pump driven by a driving system of the electric vehicle with an inlet communicated with the oil container and an outlet communicated with the first and second clutch driving circuits respectively; a fifth check valve connected in series at an outlet side of the internal pump; an external pump driven by an external pump motor, with an inlet of the external pump being communicated with the oil container and an outlet of the external pump being communicated with the first and second clutch driving circuits
Implementation Method 2
the fifth check valve and the internal pump connected in series and the sixth check valve and the external pump connected in series are connected in parallel between the oil container and the first and second clutch driving circuits
Data Source
Figure 1
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AI summary
A hydraulic system of an electric vehicle may comprise: an oil container (1); a first and a second clutch driving circuits (L1, L2) connected in parallel; an internal pump (5) driven by a driving system of the electric vehicle; a fifth check valve (8) connected in series at an outlet side of the internal pump (5); an external pump (13) driven by an external pump motor (M); and a sixth check valve (14) connected in series at an outlet side of the external pump (13). The fifth check valve (8) and the internal pump (5) connected in series and the sixth check valve (14) and the external pump (13) connected in series may be connected in parallel between the oil container (1) and the first and second clutch driving circuits (L1, L2). A driving system and an electric vehicle comprising the same may also be provided.