Freewheel Mode Control for Engine-Off Vehicle Coasting
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Solution Overview
Problem
Current motor vehicle systems face challenges in optimizing fuel consumption and improving comfort and safety when entering and leaving a freewheel running condition with the internal combustion engine off, particularly in managing transitions and ensuring efficient energy management.
Innovation Solution
An automotive electronic control system that detects driver intentions and vehicle conditions to seamlessly enter and exit a freewheel running condition by disengaging or engaging the driveline and internal combustion engine, using various cranking modes and speed ratios, while managing energy storage devices and on-board systems to optimize fuel efficiency and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the internal combustion engine is switched off and the driveline is disengaged to reduce fuel consumption, then fuel efficiency is improved, but the complexity of control systems increases
Solution Approach 1:
The control system continuously monitors multiple parameters including accelerator pedal position, brake pedal status, vehicle speed, and gear position to dynamically determine when to engage or disengage the driveline and switch the engine on or off. This feedback mechanism enables automated decision-making that reduces fuel consumption while managing system complexity through intelligent control logic
Solution Approach 2:
The system predicts driver intentions by monitoring accelerator pedal release duration and vehicle deceleration patterns before the driver actually requests engine shutdown. By anticipating the need for freewheel mode in advance, the system can prepare and execute engine-off transitions more efficiently, reducing fuel consumption while simplifying the control sequence
2Use of energy by moving object
If the driveline is disengaged to enable freewheel running condition, then fuel efficiency is improved, but the response time to provide traction power deteriorates
Solution Approach 1:
The system monitors accelerator pedal position and vehicle deceleration to predict when the driver will need traction power before the pedal is actually pressed. By anticipating the driver's intent and preparing the engine and driveline for re-engagement in advance, the system minimizes the delay between driver action and power delivery while maintaining fuel efficiency during coasting
Solution Approach 2:
The control system dynamically adjusts the timing and sequence of engine cranking and driveline re-engagement based on real-time vehicle conditions, speed, and predicted driver needs. This dynamic control optimizes the transition speed and response characteristics, ensuring rapid power delivery when needed while maximizing the duration of fuel-efficient freewheel operation
3Speed
If the engine is cranked and driveline re-engaged quickly to improve response time, then traction power availability is improved, but fuel consumption during transition increases
Solution Approach 1:
The system dynamically optimizes the sequence and timing of engine cranking, clutch engagement, and gear selection based on current vehicle speed, load conditions, and predicted driver requirements. By adjusting these parameters in real-time, the system achieves the fastest possible response while minimizing the duration and intensity of fuel-consuming transition operations
Solution Approach 2:
The control system prepares the engine and driveline components for re-engagement before the driver actually requests power, by pre-conditioning the engine state and positioning the driveline for rapid coupling. This preliminary preparation reduces the actual transition time and fuel consumption during the critical re-engagement phase
Data Source
AI summary
The present invention relates to an automotive electronic control system (E-ECU, PWT-ECU; ECU) for a motor vehicle (MV) comprising a powertrain (PWT) and an electric system (ES); the powertrain (PWT) comprises an internal combustion engine (ICE) and a driveline (T); the driveline (T) comprises a gearbox (G) and a clutch (C); the electrical system (ES) comprises electrical energy storage devices (ACC1, ACC2); the automotive electronic control system (E-ECU, PWT-ECU; ECU) is designed to receive quantities indicative of operative conditions of the motor vehicle (MV), of the powertrain (PWT) and on-vehicle systems/components; the automotive electronic control system (E-ECU, PWT-ECU; ECU) is designed to cause the motor vehicle (MV) to enter a freewheel running condition with internal combustion engine off if the automotive electronic control system ( E-ECU, PWT-ECU; ECU) determines, based on the received quantities, occurrence of a driver-performable action indicative of the will of the driver to enter a freewheel running condition with internal combustion engine off and occurrence at or within a given time (τES&S1) from the occurrence of the driver-performable action and the maintaining for a given time (τES&S2) of specific predetermined entry conditions; the automotive electronic control system (E-ECU, PWT-ECU; ECU) is further designed to cause the motor vehicle (MV) to leave a freewheel running condition with internal combustion engine off if the automotive electronic control system (E-ECU, PWT-ECU; ECU) determines, based on the received quantities received, occurrence of at least one of specific predetermined exit conditions.