Engine Control Method for Inertial Travel Noise Reduction

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Solution Overview

Problem

The rotation of engines does not immediately stop after the start of inertial traveling, leading to discomfort due to noise generated by engine cranking during inertial rotation when a condition to stop inertial traveling is satisfied.

Innovation Solution

An engine control method that determines the driver's intention for acceleration, stops fuel supply to the engine when no intention for acceleration is detected, prohibits engine restart until the rotational speed drops below a predetermined threshold, and restarts the engine after it reaches this threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the engine is restarted immediately when a condition to stop inertial traveling is satisfied, then the response to driver acceleration intention is improved, but noise is generated during inertial rotation causing driver discomfort

Engineering Contradiction:
Improveresponse speedVSAvoidnoise
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The control device determines driver acceleration intention in advance during inertial traveling and prepares for engine restart, but delays actual restart execution until engine rotational speed drops below the threshold. This preliminary determination combined with conditional delayed execution resolves the contradiction by preparing response while avoiding noise.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the engine restart is prohibited until rotational speed drops below threshold, then noise is prevented, but response timing to driver acceleration intention is delayed

Engineering Contradiction:
ImprovenoiseVSAvoidresponse time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The control device dynamically adjusts the engine restart timing based on real-time rotational speed conditions. When acceleration intention is detected, the system monitors rotational speed and executes restart only when speed drops below threshold, creating a dynamic response that adapts to engine state rather than using fixed timing.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If fuel supply is stopped during inertial traveling, then fuel efficiency is improved, but engine restart must be managed carefully to avoid noise

Engineering Contradiction:
Improvefuel efficiencyVSAvoidnoise
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The control device changes the fuel supply parameter from normal supply to stopped supply during inertial traveling, improving fuel efficiency. Simultaneously, it controls the restart parameter by monitoring rotational speed and only permitting restart when speed drops below threshold, thus avoiding noise while maintaining fuel efficiency benefits.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3327271B1Engine control method and vehicle drive control device
Publication Date: 2020.02.19 NISSAN MOTOR CO LTD
  • EP3327271B1 patent drawingFigure 1
  • EP3327271B1 patent drawingFigure 2
  • EP3327271B1 patent drawingFigure 3

AI summary

An engine control method, including: determining an intention of a driver for acceleration during vehicle (1) traveling; stopping fuel supply to an engine (2) when it is determined that the driver does not have the intention for acceleration; permitting restart of the engine (2) when it is determined that the driver has the intention for acceleration after stopping the fuel supply to the engine (2); prohibiting the restart of the engine (2) until an engine rotational speed (Re) drops to or below a predetermined rotational speed threshold (Tr), even when the restart of the engine (2) is permitted; and restarting the engine (2) after the engine rotational speed (Re) drops to or below the predetermined rotational speed threshold (Tr) .