Powertrain Clutch Control for Energy-Efficient Rolling Mode

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Solution Overview

Problem

Existing methods for controlling and regulating a motor vehicle's drive train are not optimally designed, leading to inefficient energy use, high fuel consumption, and increased CO2 emissions, particularly when transitioning between operating modes.

Innovation Solution

The method involves controlling the clutch based on brake pedal actuation, engine status, and additional factors like accelerator pedal input and geographic/data from cruise control systems, preventing direct transitions to overrun mode and ensuring the engine operates in idling or starting modes for reduced drive losses and enhanced flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the clutch is opened and the vehicle operates in overrun mode after brake pedal release, then the transition speed is improved, but drive losses and fuel consumption increase

Engineering Contradiction:
Improvetransition speedVSAvoiddrive losses
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The engine is started in advance during coasting mode before the brake pedal is released, so that when the clutch needs to be re-engaged after braking, the engine is already running and ready, avoiding the need to operate in inefficient overrun mode and reducing energy losses during mode transitions

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If the clutch is opened and the vehicle operates in overrun mode, then the response time is improved, but CO2 emissions increase

Engineering Contradiction:
Improveresponse timeVSAvoidCO2 emissions
Core Design Contradiction:
Loss of timeVSObject-generated harmful factors

Solution Approach 1:

The engine is pre-started during coasting mode to ensure immediate readiness when needed, eliminating the need for high-emission overrun operation while maintaining fast response capability for subsequent driving modes

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the engine is started during coasting mode, then the adaptability for subsequent operating modes is improved, but the engine complexity increases

Engineering Contradiction:
Improveoperating mode flexibilityVSAvoidengine control complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The engine is started in advance during coasting mode to prepare for potential subsequent operating modes, and the control unit manages this pre-start operation to simplify the overall control logic by handling the engine start sequence proactively rather than reactively

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control unit continuously monitors driving conditions, brake pedal status, and engine state to make intelligent decisions about when to start the engine during coasting mode, optimizing the balance between adaptability and control complexity through condition-based feedback control

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3554908B1Method for the open-loop and/or closed-loop control of a powertrain of a motor vehicle
Publication Date: 2023.07.12 VOLKSWAGEN AG
  • EP3554908B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for the open-loop and/or closed-loop control of a powertrain (1) of a motor vehicle, wherein the powertrain (1) has at least one internal combustion engine (2), at least one automatic transmission (3), in particular an automated manual transmission (3a), and at least one clutch (4) effectively arranged between the internal combustion engine and the automatic transmission. At least one control unit (5), in particular a transmission control unit (5b) and/or an engine control unit (5a), is provided, wherein with the help of the control unit (5), the clutch (4) is opened or closed depending on defined operating conditions during a journey of the motor vehicle. If the clutch (4) is closed, the internal combustion engine (2) is effectively coupled to the automatic transmission (3) and if the clutch (4) is open, the internal combustion engine (2) is effectively decoupled from the automatic transmission (3). If the clutch (4) is open, the motor vehicle can be operated in a rolling mode when the internal combustion engine (2) is running, or if the clutch (4) is open, the motor vehicle can be operated in a freewheel mode when the internal combustion engine (2) is turned off, and, in the rolling mode or freewheel mode, the clutch (4) is closed if the brake pedal or the drive pedal is actuated. The powertrain is flexibly and energy- and cost-efficiently designed because at the end of the brake pedal actuation, the clutch (4) is opened and a rolling mode of the motor vehicle is then effected, wherein if the internal combustion engine (2) was previously turned off, the internal combustion engine (2) is started and operated in neutral, or if the internal combustion engine (2) was already running, it is then operated in neutral.