Combined Engine Start Method Reducing Starter Load
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Solution Overview
Problem
Existing methods for starting an internal combustion engine in vehicles, such as tow-starting and pure starter-starting, face challenges like high starter load, noise, and increased wheel torque, especially at low speeds, leading to inefficiencies and discomfort for the driver.
Innovation Solution
A combined engine start method that uses a combination of closing the clutch and engaging the starter to start the engine during coasting, allowing for reduced starter load and lower wheel torque, with a controller determining the optimal start method based on driving parameters and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric starter is used to start the internal combustion engine during coasting, then the engine can be restarted reliably, but the starter is exposed to high number of cycles leading to increased wear and requires larger, more robust design
Solution Approach 1:
The patent combines two starting methods (electric starter and tow-start) into a hybrid approach. The controller selectively activates the electric starter for a limited duration during clutch engagement, merging the reliability of electric starting with the reduced wear benefit of tow-starting, thereby reducing overall starter cycle exposure while maintaining restart reliability
2Device complexity
If a pure tow-start is used to start the internal combustion engine during coasting, then the starter load is reduced, but the wheel torques increase significantly especially at low speeds causing noticeable deceleration
Solution Approach 1:
The patent merges the gentle torque characteristics of electric starting with the reduced starter wear of tow-starting. By applying electric starter torque during clutch engagement, the system reduces the torque demand on the wheels during clutch closure while still achieving engine start, thus mitigating the harmful deceleration effect
Solution Approach 2:
The patent dynamically adjusts the starting approach based on vehicle speed and operating conditions. At higher speeds where tow-start is feasible, the system uses reduced electric starter activation. At lower speeds where pure tow-start would cause excessive deceleration, the system increases electric starter involvement, creating a dynamic balance between starter load and wheel torque
3Ease of operation
If the clutch is closed very slowly during tow-start to remove kinetic energy imperceptibly, then driver comfort is improved, but the engine start time is significantly lengthened
Solution Approach 1:
The patent combines the comfort benefit of slow clutch engagement with the speed benefit of electric assistance. The electric starter provides torque support during clutch engagement, allowing the clutch to close faster without causing perceptible deceleration, thus achieving both driver comfort and reduced start time simultaneously
4Reliability
If the electric starter is activated for a longer duration during combined start, then the engine starts more reliably, but the starter load and energy consumption increase
Solution Approach 1:
The patent dynamically controls the electric starter activation duration based on real-time parameters including vehicle speed, engine conditions, and clutch engagement state. The controller adjusts the activation timing to provide sufficient torque for reliable starting while minimizing energy consumption, achieving optimal balance between reliability and energy efficiency
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
This approach significantly reduces starter load and starting time, provides a comfortable and quick engine start, and ensures energy efficiency even on slippery roads by leveraging kinetic energy once the engine is running.
Implementation Method 1
at least one starter (12) for starting the internal combustion engine
Implementation Method 2
at least one clutch (2) coupled to an output shaft of the internal combustion engine on the input side and to the drive wheels of the motor vehicle on the output side
Implementation Method 3
starting an internal combustion engine of a motor vehicle
Data Source
AI summary
A method for starting the internal combustion engine of a motor vehicle, comprising at least one starter motor for starting the internal combustion engine, and at least one clutch coupled on the input side to an output shaft of the internal combustion engine and on the output side to the drive wheels of the motor vehicle, wherein, while the motor vehicle is coasting (rolling freely with the internal combustion engine switched off and the clutch disengaged), the internal combustion engine can be started by engaging the clutch. A fast, convenient, and energy-efficient engine start is achieved by enabling a combined engine start during coasting, achieved through a combination of engaging the clutch and using the starter motor.