Hybrid Engine Switching Timing for Target Stop Position

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Solution Overview

Problem

Existing driving assistance systems for hybrid vehicles face limitations in assisting vehicles to stop at a target position while improving fuel economy, requiring increased accelerator operation and having limited fuel economy improvements.

Innovation Solution

A driving assistance apparatus that includes an assistance control unit determining the engine's on/off state and a drive control unit to optimize engine switching, allowing the vehicle to coast to a target stopping position by calculating the timing and setting thresholds based on vehicle speed, deceleration, and battery state of charge, thereby reducing fuel consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the engine is switched off to improve fuel economy, then fuel consumption is reduced, but the vehicle cannot reach the target stopping position without increasing accelerator operation

Engineering Contradiction:
Improvefuel consumptionVSAvoidaccelerator operation amount
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The system calculates in advance whether the vehicle can reach the target stopping position by coasting from the current position, and determines the appropriate timing to switch the engine off before reaching the stopping position, allowing the vehicle to coast to the target position without requiring additional accelerator input from the driver

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If the engine is switched off earlier to improve fuel economy, then fuel consumption is reduced, but the vehicle may not be able to reach the target stopping position

Engineering Contradiction:
Improvefuel consumptionVSAvoidability to reach target stopping position
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system continuously monitors the current position, target stopping position, and vehicle speed, and dynamically adjusts the engine off timing based on whether the vehicle can reach the target position by coasting, ensuring reliable stopping while maximizing fuel economy

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If the engine switching threshold is set to a higher value to improve fuel economy, then fuel consumption is reduced, but the engine switches off at inappropriate timing affecting driving assistance quality

Engineering Contradiction:
Improvefuel consumptionVSAvoiddriving assistance quality
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The system dynamically adjusts the engine off threshold parameter based on the calculated distance to the target stopping position and current vehicle speed, rather than using a fixed threshold, allowing the engine to remain on when needed for proper driving assistance and switch off when safe to do so for fuel economy

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2781722B1Driving assistance apparatus
Publication Date: 2018.06.13 TOYOTA JIDOSHA KK
  • EP2781722B1 patent drawingFigure 1
  • EP2781722B1 patent drawingFigure 2
  • EP2781722B1 patent drawingFigure 3

AI summary

A driving assistance apparatus (1) includes an assistance control unit (50) determining an on/off state of an engine (5) and a drive control unit (54c) controlling driving of the engine (5) on the basis of the on/off state determined by the assistance control unit (50). The assistance control unit (50) determines whether a vehicle stops at a target stopping position, and carries out setting such that the engine (5) is more easily switched from the on state to the off state when the assistance control unit (50) determines to stop at the target stopping position and it is timing at which the vehicle is able to reach the target stopping position in a state where driving force is not generated.