Vehicle Clutch Control for Push-Start Engine Restart

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Solution Overview

Problem

The frequent engine start-stop cycles during inertia traveling modes in vehicles lead to reduced durability of the starter motor and potential drivability issues due to clutch engagement shocks.

Innovation Solution

A vehicle control device that disengages the clutch between the engine and driving wheel during brake-off and accelerator-off, allowing for engine stoppage and inertia traveling, and restarts the engine via push-start by engaging the clutch when the brake pedal is depressed, using kinetic energy from the driving wheel to alleviate shock and reduce starter motor usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the engine is stopped during inertia traveling to improve fuel efficiency, then fuel efficiency is improved, but the starter motor durability deteriorates due to frequent start-stop cycles

Engineering Contradiction:
Improvefuel efficiencyVSAvoidstarter motor durability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent extracts the engine starting function from the starter motor by introducing a push-start mechanism that uses the vehicle's kinetic energy to rotate the engine crankshaft directly, thereby removing the reliance on the starter motor for engine restarts during inertia traveling modes

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The vehicle's own kinetic energy during coasting is utilized to restart the engine through the push-start mechanism, making the system self-sufficient and eliminating the need for external power sources like the starter motor

Inventive Principle:
Principle #25Self-service

2Reliability

If push-start by engaging the clutch is used to start the engine, then starter motor durability is improved, but drivability deteriorates due to shock when the clutch is engaged

Engineering Contradiction:
Improvestarter motor durabilityVSAvoiddrivability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The clutch engagement is made dynamic and adaptive through electronic control that adjusts the engagement timing and speed based on vehicle conditions, transforming the rigid mechanical engagement into a controllable, shock-mitigated process

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The clutch is engaged in advance before the engine restart is fully completed, allowing the engine to be driven by the clutch gradually, which reduces the shock that would occur from direct engagement after engine stop

Inventive Principle:
Principle #10Preliminary action

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 method improves starter motor durability and maintains drivability by reducing clutch engagement shocks and minimizing starter motor usage, while ensuring efficient engine re-starts during inertia traveling.

Implementation Method 1

the engine is started by the push-start by engaging the clutch and by transmitting the power of the driving wheel to the engine

Methodology Applied
Scientific EffectKinetic energy transmission: Mechanical Force

Data Source

PatentEP3179125B1Vehicle control device, and vehicle control method
Publication Date: 2019.10.30 NISSAN MOTOR CO LTD
  • EP3179125B1 patent drawingFigure 1
  • EP3179125B1 patent drawingFigure 2

AI summary

A vehicle control device disengages a clutch provided between an engine and a driving wheel at a brake-off and an accelerator-off during traveling of the vehicle, and stops the engine and carries out inertia traveling. The vehicle control device starts the engine by the push-start by engaging the clutch and by transmitting the power of the driving wheel to the engine, if it is determined that a brake pedal has been depressed during the inertia traveling.