Vehicle Gear Shifting Fuel Cut Control

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Solution Overview

Problem

Gear shifting in vehicles with Otto-engines and manually actuated clutches is slow and inefficient, leading to impaired manoeuvrability, engine misfires, and noise emissions, due to the inherent characteristics of actuator means and air dynamics, which can damage emission control systems.

Innovation Solution

A method and system that determine specific condition parameter values, including clutch position, engine torque, and speed, to activate a forced fuel cut function before disengaging the transmission, allowing for rapid gear shifting by interrupting fuel provision, thereby reducing engine torque and improving shifting speed and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional gear shifting with throttle and dump valve control is used, then engine air dynamics are maintained, but gear shifting time is excessively long and vehicle manoeuvrability is impaired

Engineering Contradiction:

Improvegear shifting speedVSAvoidgear shifting time

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The control unit activates the fuel cut function before the gear shift is initiated, preparing the engine for rapid torque reduction. By preemptively cutting fuel supply when clutch disengagement is detected, the system eliminates the delay associated with conventional throttle and dump valve operations, enabling immediate torque drop and accelerating gear shift execution

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system fundamentally changes the engine operating parameters by cutting fuel supply entirely during gear shift, transitioning from combustion to inert rotation mode. This parameter change allows engine torque to drop to near-zero levels instantly, bypassing the slow air dynamics control of conventional systems and achieving rapid gear shifting without compromising vehicle manoeuvrability

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional fuel control during gear shift is used, then engine operation is maintained, but engine misfires occur and emission control components are damaged

Engineering Contradiction:

Improveemission control system reliabilityVSAvoidengine misfire

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control unit detects clutch disengagement and activates the fuel cut function before the gear shift process begins. This preliminary action ensures that no fuel is injected into the combustion chamber during the transition, preventing misfires that would otherwise occur due to abrupt air flow changes and protecting emission control components from damage

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system converts the potentially harmful effect of abrupt air flow changes during gear shift into a beneficial outcome by cutting fuel supply. Instead of allowing misfires caused by air dynamics disruptions, the fuel cut transforms the situation into a controlled inert rotation state, eliminating misfires and protecting the emission control system while still enabling rapid gear shifting

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of time

If rapid torque reduction is achieved through forced fuel cut, then gear shifting time is reduced, but engine speed oscillations may increase

Engineering Contradiction:

Improvegear shifting timeVSAvoidengine speed stability

Core Design Contradiction:

Loss of timeVSStability of the object's composition

Solution Approach 1:

The control unit continuously monitors engine speed and other operating parameters during the gear shift process. Based on this feedback, the system can modulate the fuel cut duration and timing, adjusting the torque reduction profile to minimize engine speed oscillations while maintaining rapid gear shift execution. The feedback loop ensures stable engine operation throughout the transition

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3400157B1A method and a system for improved gear shifting of a transmission

Publication Date: 2021.03.17 SCANIA CV AB

Figure 1~2a
Figure 2b~2c
Figure 3~4a

AI summary

The invention relates to a method for improved gear shifting of a vehicle (100) having an Otto-engine (231) and a manually actuated clutch (241) of the vehicle transmission, comprising the steps of: - determining a first set (S1) of condition parameter values, said parameters comprising clutch position (CP), requested engine torque (Tq_demand) and engine speed (Neng); - determining if said first set (S1) of condition parameter values meet first predetermined conditions; - if said first predetermined conditions of said first set of condition parameter values are met, activating a function (F) for interrupting fuel provision of said engine (231) before disengaging said vehicle transmission during gear shifting. The invention relates also to a computer programme product comprising program code (P) for a computer (200; 210) for implementing a method according to the invention. The invention relates also to a system for improved gear shifting of a vehicle having an Otto- engine and a manually actuated clutch of the vehicle transmission and a motor vehicle (100) equipped with the system.