Freewheel Clutch Element for Drive Unit Power Transition
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Solution Overview
Problem
Existing drive units for motor vehicles require significant production and control expenditure to maintain clutch engagement during internal combustion engine operation, leading to wear and susceptibility to failure, and demand complex control to ensure uninterrupted auxiliary unit drive.
Innovation Solution
A drive unit featuring a freewheel clutch element that connects the internal combustion engine to auxiliary units via a belt drive, allowing demand-driven operation with the internal combustion engine on or off, and incorporating a starter-generator or separate electric motor to prevent unintended power transmission, reducing control and construction demands by using a lockable freewheel mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch remains engaged during internal combustion engine operation to drive auxiliary units, then the auxiliary units receive continuous power, but the clutch experiences wear and increased susceptibility to failure
Solution Approach 1:
The clutch is engaged only periodically during starter motor operation to crank the internal combustion engine, rather than remaining continuously engaged. This periodic engagement significantly reduces wear and extends clutch service life while still achieving the necessary function of starting the engine and driving auxiliary units when needed.
Solution Approach 2:
The clutch is extracted from the continuous power transmission path and positioned only in the starter motor circuit. This allows the main engine-to-auxiliary-unit power transmission to occur through other means (such as belt drives) while the clutch is only activated when starter motor engagement is required, minimizing wear.
2Ease of operation
If the clutch remains engaged to ensure uninterrupted auxiliary unit drive, then auxiliary units operate continuously, but production expenditure and control complexity increase
Solution Approach 1:
The clutch operates periodically only during starter motor engagement rather than continuously, simplifying the control system. The control unit needs to manage clutch engagement only during specific starting conditions, reducing overall control complexity while still ensuring auxiliary units receive power when the engine is running.
Solution Approach 2:
The clutch serves as an intermediary element specifically for the starter motor circuit, separating the starting function from the main power transmission function. This allows independent control of starter engagement without affecting the continuous operation of auxiliary units during engine operation.
3Adaptability or versatility
If the clutch is engaged frequently to switch between engine and starter-generator power, then flexibility is improved, but wear and failure risk increase
Solution Approach 1:
The clutch is extracted from the main engine power transmission path and positioned only in the starter motor circuit. This extraction eliminates the need for frequent engagement/disengagement cycles during normal operation, as the clutch only engages when the starter motor needs to crank the engine, thereby reducing wear while maintaining the flexibility to switch power sources when needed.
Solution Approach 2:
The clutch engages periodically only during starter motor operation rather than frequently during normal power transmission. This periodic action pattern reduces the total number of engagement cycles, minimizing wear and improving durability while still providing the necessary flexibility for engine starting and power source switching.
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
Simplifies control and construction of the clutch element by allowing seamless transition between internal combustion engine and starter-generator or electric motor power, minimizing wear and reducing the need for constant engagement, thus enhancing the reliability and efficiency of auxiliary unit operation.
Implementation Method 1
a clutch element provided with a freewheel, the auxiliary unit being configured to be driven via the clutch element on demand during operation of the internal combustion engine and when the internal combustion engine is switched off
Data Source
AI summary
An internal combustion engine drives, via a belt drive, a first and a second auxiliary unit embodied respectively as a water pump and an air-conditioning compressor and drives a starter-generator operating as a starter and as a generator depending on the operating mode. The belt drive is connected through a clutch element, which has a freewheel, to the internal combustion engine such that, when the internal combustion engine is at standstill, only the two auxiliary units, but not at the same time the internal combustion engine, are driven by the starter-generator. The clutch element which has a freewheel allows a stepless transition of the drive mode from the internal combustion engine to the starter-generator. In order to start the internal combustion engine, the clutch element is engaged only for a short time, so that the drive power of the starter-generator is transmitted to the internal combustion engine.