Drivetrain Decoupling for Engine Braking Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing kinetic energy recovery systems for motor vehicles have low conversion efficiency between energy system components, and internal combustion engines with automatic transmissions face challenges in reducing braking torques and kinetic energy, leading to inefficient energy saving.
Innovation Solution
A method and control system for a motor vehicle with a manual transmission that automatically decouples the engine from the vehicle wheels when the accelerator pedal is released, using a driver-operated clutch and sensors to detect conditions like road grade and ambient temperature, allowing the vehicle to coast without engine braking, thereby reducing fuel consumption and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If kinetic energy recovery systems are used to convert kinetic energy into electrical energy, then energy can be stored and reused for vehicle propulsion, but conversion efficiency between energy system components remains low
Solution Approach 1:
The patent extracts the energy recovery function from the main drivetrain by introducing a separate auxiliary power unit (APU) with its own energy storage system. This allows kinetic energy to be recovered and stored independently without interfering with the primary engine-transmission system, thereby reducing conversion losses while maintaining manageable system complexity through functional separation.
Solution Approach 2:
The patent introduces an intermediary energy storage device (such as a high-power capacitor or flywheel) between the kinetic energy source and the propulsion system. This intermediary allows efficient energy capture during braking and rapid energy delivery during acceleration, improving overall conversion efficiency while isolating the complexity of energy management from the main drivetrain.
2Speed
If engine braking is applied during vehicle coasting, then vehicle speed is controlled, but fuel consumption increases and coasting distance is reduced
Solution Approach 1:
The patent implements dynamic engine management by automatically adjusting engine operation based on real-time driving conditions. During coasting phases, the engine is automatically decoupled from the drivetrain using a clutch mechanism, eliminating engine braking and allowing the vehicle to coast farther on its momentum. When acceleration is needed, the engine is re-engaged, creating a dynamic system that optimizes fuel consumption while maintaining speed control capability.
Solution Approach 2:
The patent employs feedback control through sensors that monitor accelerator pedal position, vehicle speed, and drivetrain conditions. This feedback enables the control system to detect when the driver is coasting (accelerator released) and automatically respond by decoupling the engine, thereby reducing fuel consumption during coasting while maintaining the ability to provide engine braking when needed for speed control.
3Length of moving object
If the drivetrain is opened to reduce braking torques, then vehicle deceleration is reduced and coasting distance increases, but conversion efficiency of energy recovery systems decreases
Solution Approach 1:
The patent segments the energy recovery function from the main drivetrain by using a separate auxiliary power unit with independent energy storage. This segmentation allows the main drivetrain to be opened (clutch disengaged) during coasting to maximize coasting distance, while the separate APU can still independently recover kinetic energy during braking events without being affected by the open drivetrain condition, thus maintaining energy recovery efficiency while achieving longer coasting distances.
Data Source
AI summary
A system and method for selectively opening a drivetrain of a vehicle is described. In one example, an electrically operated clutch is opened during selected driving conditions to conserve kinetic energy of the vehicle. The method may reduce fuel consumption during selected conditions.