Stop/Start Engine Control via Brake Force Feedback
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Solution Overview
Problem
Existing engine systems fail to effectively conserve fuel when frequently stopped and restarted, leading to unnecessary fuel consumption and potential vehicle movement on inclines without driver intent, due to inadequate braking force detection.
Innovation Solution
The system stops engine rotation when sufficient braking force is applied to hold the vehicle, allowing the engine to remain off and combining engine creep torque with braking torque to limit motion, while maintaining vacuum for improved braking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is stopped to conserve fuel, then fuel consumption is reduced, but the driver may become aggravated if the brake pedal is inadvertently released or the vehicle moves on an incline
Solution Approach 1:
The system continuously monitors brake pedal position and vehicle motion status, using feedback signals to determine whether to stop or restart the engine. This closed-loop control ensures the engine remains stopped only when it is safe to do so, preventing unintended vehicle movement while maximizing fuel savings.
Solution Approach 2:
The control system acts as an intermediary between the driver's brake pedal input and the engine stop/start function. It interprets the driver's intent by analyzing brake pedal position and vehicle status, making intelligent decisions about engine operation that balance fuel economy with vehicle stability and driver intent.
2Ease of operation
If the engine is restarted when the brake pedal is partially released, then the vehicle can launch, but fuel conservation is not realized
Solution Approach 1:
The engine stop/start system dynamically adjusts its behavior based on real-time driving conditions. It transitions between stopped and running states based on brake pedal position, vehicle speed, and other operational parameters, optimizing the balance between fuel conservation and vehicle responsiveness.
Solution Approach 2:
The system changes operational parameters (engine on/off state) based on detected driving conditions. By monitoring parameters such as brake pedal position, vehicle speed, and incline, the system intelligently transitions the engine between states to achieve fuel savings without compromising vehicle launch capability when needed.
3Use of energy by moving object
If the engine remains off for longer periods, then fuel consumption is reduced, but braking vacuum may be insufficient for effective braking
Solution Approach 1:
The system builds up braking vacuum in advance by running the engine briefly before a stop or during conditions where vacuum can be stored. This preliminary action ensures that sufficient vacuum is available for effective braking when the engine is subsequently stopped, allowing the system to maintain fuel savings while ensuring braking capability.
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 engine fuel consumption, enhances vehicle drivability, and extends driveline life by allowing the engine to remain off for longer periods and maintaining vehicle stability on inclines.
Implementation Method 1
combusting an air-fuel mixture in an engine
Implementation Method 2
applying vehicle brakes in response to the driver at least partially releasing the brake pedal
Data Source
AI summary
Systems and methods for improving operation of a vehicle are presented. In one example, vehicle brakes are held to reduce the possibility of vehicle motion and stopping of engine rotation is prevented until confirmation of vehicle hold is present. The approach may allow an engine to remain in an off state for a longer period of time while reducing the possibility of vehicle motion.