Automated Manual Transmission Gear Shift Control

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Solution Overview

Problem

Existing gear shift methods in motor vehicles with automated manual transmissions are inefficient, often taking too long to reach target engine speeds, leading to unwanted deceleration or acceleration during gear changes.

Innovation Solution

A method that controls clutch torque to enable gear shifts before target engine speed is reached, and subsequently adjusts engine torque based on clutch torque, allowing for robust and time-efficient gear changes by initiating engine torque control when clutch sliding stops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If engine torque is controlled to reach target speed before gear shift, then gear shift timing is precise, but gear shift time becomes too long

Engineering Contradiction:

Improvegear shift timing precisionVSAvoidgear shift duration

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The clutch torque is controlled in advance during the gear shift procedure to enable the gear shift to occur before the target engine speed is reached. This preliminary control of clutch torque allows the gear shift to be executed at the optimal moment without waiting for the engine to reach the predetermined target speed, thereby reducing overall gear shift time while maintaining precise timing control.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If clutch torque is controlled to enable early gear shift, then gear shift time is reduced, but clutch sliding control becomes complex

Engineering Contradiction:

Improvegear shift durationVSAvoidcontrol system complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

When the clutch stops sliding, the system transitions to controlling engine torque based on clutch torque feedback. This feedback mechanism allows the control system to adaptively adjust engine torque according to the actual clutch state, simplifying the overall control strategy while achieving precise gear shift timing and reducing clutch sliding complexity through state-based control transitions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control system dynamically switches between two modes: initially controlling clutch torque to enable early gear shift, then transitioning to controlling engine torque based on clutch torque when sliding stops. This dynamic adaptation of control strategy based on system state reduces complexity by dividing the control procedure into distinct phases with different control objectives.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If engine torque is controlled throughout complete gear shift procedure, then engine speed is precisely controlled, but system robustness decreases

Engineering Contradiction:

Improveengine speed control precisionVSAvoidsystem robustness

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The gear shift procedure is segmented into two distinct phases: first, controlling clutch torque to enable the gear shift before target speed is reached; second, when the clutch stops sliding, controlling engine torque based on clutch torque. This segmentation allows each phase to be optimized independently, improving overall system robustness while maintaining necessary precision during critical transitions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of controlling engine torque throughout the complete gear shift procedure, the invention applies partial control - initially controlling only clutch torque during the critical gear shift moment, then transitioning to engine torque control based on clutch torque afterward. This partial control approach reduces system complexity and improves robustness while maintaining sufficient precision for safe operation.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP2473385B1Device and method for performing a gear change of a vehicle

Publication Date: 2015.03.25 SCANIA CV AB

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AI summary

The invention relates to a method for executing a gear shift step in a motor vehicle (100; 110) comprising an engine (220) and an automated manual transmission incorporating a clutch (230) and a gearbox (240), which method comprises the steps, during a gear shift procedure, of: - controlling a torque (Tc) in said clutch (230) in order to make it possible for said gear shift step to take place before a target speed (rpm*) of the engine (220) is reached; and, when said clutch (230) has stopped sliding, of controlling a torque (Te) of the engine (220) on the basis of the torque (Tc) in the clutch (230). The invention relates also to a computer program product comprising program code (P) for a computer (200; 210) for executing a method according to the invention. The invention relates also to a device for executing a gear shift step in a motor vehicle (100; 110) comprising an engine (220) and an automated manual transmission incorporating a clutch (230) and a gearbox (240), and to a motor vehicle that is equipped with the device.