Vehicle KERS Stop-Start Control for Low-Emission Launch
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Solution Overview
Problem
Heavy-duty vehicles propelled by internal combustion engines face challenges in reducing fuel consumption, noise, and pollutant emissions due to the complexity and high cost of existing start-stop and hybrid systems.
Innovation Solution
A method that incorporates a kinetic energy recovery system to store and restore mechanical energy, allowing the vehicle to propel the wheel propulsion shaft and/or crank the internal combustion engine, with a control unit managing energy thresholds to optimize engine use, including exclusive use of kinetic energy for propulsion and strategic engine cranking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a start-stop system is implemented to reduce fuel consumption and emissions, then fuel consumption and emissions are reduced, but the system complexity increases due to reliance on vehicle starter
Solution Approach 1:
The system separates the energy storage function from the starter motor by introducing a dedicated kinetic energy recovery system with flywheel and clutch mechanisms. This segmentation allows the starter to be used only when necessary while the kinetic energy recovery system handles stop-start operations independently, reducing overall system complexity.
Solution Approach 2:
The kinetic energy recovery system acts as an intermediary between the engine and wheels, capturing energy during deceleration and releasing it during acceleration. This intermediary mechanism reduces the workload on the starter motor and enables more frequent stop-start operations without increasing starter complexity.
2Loss of energy
If hybrid systems with electric motors are used to recover and store kinetic energy, then fuel consumption is reduced, but the system complexity and cost increase significantly
Solution Approach 1:
The invention extracts the kinetic energy recovery function from the complex hybrid electric system and implements it using a purely mechanical approach with flywheel and clutch mechanisms. This extraction eliminates the need for electric motors, batteries, and complex power management systems while maintaining energy recovery functionality.
Solution Approach 2:
The mechanical kinetic energy recovery system uses simple, inexpensive components like flywheels and clutches that can be easily manufactured and replaced. These components are less complex and cheaper than hybrid electric system components, making the overall system more cost-effective despite slightly reduced energy recovery efficiency.
3Object-generated harmful factors
If the engine is stopped frequently to reduce emissions, then emissions are reduced, but the vehicle may lack sufficient power for acceleration
Solution Approach 1:
The kinetic energy recovery system performs preliminary energy storage during deceleration phases, accumulating mechanical energy in the flywheel. This preliminary action ensures that sufficient energy is available when acceleration is needed, allowing the engine to remain stopped longer without compromising acceleration performance.
Solution Approach 2:
The system changes the operational parameters of the engine by extending the duration of stop periods, since the kinetic energy recovery system can provide power during acceleration. This parameter change is made possible by the energy buffer provided by the flywheel, which decouples engine operation from immediate power delivery requirements.
4Ease of operation
If the starter is used frequently to crank the engine, then the start-stop system functions properly, but the starter lifespan is reduced
Solution Approach 1:
The kinetic energy recovery system provides self-service by using the stored mechanical energy to crank the engine instead of relying on the starter motor. This self-service mechanism significantly reduces starter usage frequency and extends its lifespan while maintaining start-stop functionality.
Solution Approach 2:
The system creates a periodic pattern where the kinetic energy recovery system alternates between storing energy during deceleration and using it to crank the engine during start-up. This periodic action reduces the frequency of starter activation, allowing it to last longer while maintaining proper start-stop 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
This approach reduces fuel consumption, noise, and pollutant emissions by minimizing engine use, particularly in urban environments, and extends the lifespan of the starter by reducing its operational load.
Implementation Method 1
a kinetic energy recovery system, connected to the internal combustion engine and to the wheel propulsion shaft and configured to recover and store kinetic energy of the vehicle as mechanical energy
Implementation Method 2
restore the stored energy by propelling the wheel propulsion shaft and/or by cranking the internal combustion engine
Data Source
AI summary
A vehicle comprises an internal combustion engine, a wheel propulsion shaft, wheels and a kinetic energy recovery system configured to recover and store kinetic energy of the vehicle, and restore the stored energy by propelling the wheel propulsion shaft and/or by cranking the internal combustion engine. To reduce the emissions of the vehicle, a method for operating the vehicle comprises, when the vehicle operates: when the vehicle is not stationary, recovering and storing kinetic energy of the vehicle in the KERS, when the vehicle is stationary, measuring an energy level stored in the KERS and comparing the measured energy level to a predetermined high threshold value, so that the method comprises, if the energy level stored in the KERS is above the predetermined high threshold value: stopping the internal combustion engine, then when the vehicle start is required, propelling the wheel propulsion shaft exclusively by the KERS.