Vehicle Clutch Engagement Control for Lower Selection Shock

Solution Overview

Problem

Existing vehicle control methods fail to effectively suppress selection shock when switching from a non-driving range to a driving range due to persistent feedback gain, leading to increased inertial torque and shock during clutch engagement.

Innovation Solution

The method involves reducing the engine's idling speed from a high speed (N2) to a lower speed (N3) before clutch engagement, using retard control to decrease engine speed and inertial torque, thereby minimizing selection shock by ensuring the clutch engages with less inertial torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If feedback gain is held for a prescribed amount of time when switching from non-driving range to driving range, then engine speed control stability is improved, but selection shock increases due to persistent inertial torque

Engineering Contradiction:

Improveengine speed control stabilityVSAvoidselection shock

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by detecting the shift range switch from non-driving to driving range and immediately lowering the target engine speed before clutch engagement occurs. This preemptive speed reduction prepares the engine to minimize inertial torque when the clutch connects, thereby suppressing selection shock while maintaining control stability through coordinated feedback gain management.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by dynamically adjusting the target engine speed based on the shift range state. When a driving range is selected, the target speed is lowered within the clutch engagement time period, creating a time-varying control strategy that adapts to the changing operational conditions to reduce shock during the transition.

Inventive Principle:

Principle #15Dynamics

2Power

If engine idling speed is maintained at high speed, then engine power availability is improved, but inertial torque during clutch engagement increases causing selection shock

Engineering Contradiction:

Improveengine power availabilityVSAvoidinertial torque

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by detecting the shift range switch from non-driving to driving range and immediately lowering the target engine speed before clutch engagement occurs. This preemptive speed reduction prepares the engine to minimize inertial torque when the clutch connects, thereby suppressing selection shock while maintaining control stability through coordinated feedback gain management.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by dynamically adjusting the target engine speed based on the shift range state. When a driving range is selected, the target speed is lowered within the clutch engagement time period, creating a time-varying control strategy that adapts to the changing operational conditions to reduce shock during the transition.

Inventive Principle:

Principle #15Dynamics

3Speed

If clutch engagement time is reduced, then shift response speed is improved, but selection shock increases due to insufficient time for inertial torque reduction

Engineering Contradiction:

Improveshift response speedVSAvoidselection shock

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by detecting the shift range switch from non-driving to driving range and immediately lowering the target engine speed before clutch engagement occurs. This preemptive speed reduction prepares the engine to minimize inertial torque when the clutch connects, thereby suppressing selection shock while maintaining control stability through coordinated feedback gain management.

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 approach effectively suppresses selection shock by reducing inertial torque and peak longitudinal acceleration, while also avoiding unnecessary idling speed increases and reducing the risk of catalytic converter heating.

Implementation Method 1

suppress inertial torque from an input-side rotating element of the clutch

Methodology Applied

Scientific EffectInertial torque: Inertia

Data Source

PatentUS11840973B2Vehicle control method and vehicle control apparatus

Publication Date: 2023.12.12 NISSAN MOTOR CO LTD

AI summary

A vehicle control method is provided for controlling a vehicle in which a clutch provided on a power transmission path between an engine and a drive wheel is disconnected when a shift range is a non-driving range and the clutch is connected when the shift range is a driving range. The vehicle control method controls the engine to a prescribed idling speed, controls engine torque to a negative torque by delaying an ignition timing of the engine; and causes the prescribed idling speed to drop within a prescribed amount of time needed for the clutch to switch from being disconnected to being connected when the shift range is switched from the non-driving range to the driving range.