Engine Torque Build-Up Control via Adaptive Rate Limiting

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Solution Overview

Problem

Current engine torque limiting methods in vehicles cause time delays and jerking in the power train, leading to an annoying driving experience, especially during rapid acceleration, due to inherent delays and jerks that can cause vehicle swaying or rocking.

Innovation Solution

A method that continuously identifies the maximum permissible torque and adjusts torque build-up based on the difference between this limit and the prevailing torque, ensuring a smooth and immediate response to driver demands by controlling torque as a function of this difference, reducing transients and eliminating unwanted swaying or rocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If filter functions are used to limit torque build-up, then smooth vehicle behavior is achieved, but time delays occur causing poor driver response perception

Engineering Contradiction:

Improvesmooth vehicle behaviorVSAvoidtime delay in torque response

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the torque build-up rate adaptive rather than fixed. The control unit continuously adjusts the maximum permissible torque build-up rate based on real-time conditions (engine speed, load, temperature), allowing the system to be aggressive when safe and smooth when necessary, eliminating the need for conservative fixed filter functions that cause delays.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of torque build-up rate from a static filtered value to a dynamically calculated value based on multiple engine parameters. By calculating the maximum permissible torque build-up rate as a function of engine speed, load, and temperature, the system achieves immediate response while maintaining smooth operation through parameter-based adaptation.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If filter functions are used to limit torque build-up, then torque smoothness is improved, but jerking in the power train occurs during rapid acceleration

Engineering Contradiction:

Improvetorque smoothnessVSAvoidpower train jerking

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The system uses dynamic adjustment of torque build-up rate based on real-time engine conditions. During rapid acceleration, the control unit allows higher torque build-up rates when engine parameters indicate the system can handle the load, preventing jerking while maintaining smoothness when conditions require it.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention implements feedback by continuously monitoring engine speed, load, and temperature to determine the maximum permissible torque build-up rate. This closed-loop approach ensures torque smoothness is maintained while preventing harmful jerking by adjusting the build-up rate based on actual engine state feedback.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If maximum torque is limited to prevent harmful effects, then vehicle comfort is improved, but initial torque response to driver demand is delayed

Engineering Contradiction:

Improvevehicle swaying and rockingVSAvoidtorque response speed

Core Design Contradiction:

Object-affected harmful factorsVSSpeed

Solution Approach 1:

The control unit calculates and prepares the maximum permissible torque build-up rate in advance based on current engine parameters before torque demand occurs. This preliminary calculation allows the system to immediately apply the appropriate torque build-up rate when the driver demands acceleration, eliminating response delay while preventing harmful vehicle movements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the torque limitation approach from a fixed maximum torque cap to a dynamic maximum torque build-up rate based on engine parameters. This allows faster initial torque response when engine conditions permit, while still preventing vehicle swaying and rocking by adapting the build-up rate to current operational parameters.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10731574B2Method and device for limiting the torque build-up of an engine

Publication Date: 2020.08.04 SCANIA CV AB

AI summary

A method for limitation of torque build-up of an engine (230) in a motor vehicle (100, 110), including the steps of continuously identifying (s410) a pattern pertaining to a maximum permissible torque (Tqmax); responding to torque demand (s420) by guiding torque build-up towards desired torque (Tqreq); responding to torque demand by continuously determining (s440) a difference (Tqdiff; Tqdiffnorm) between maximum permissible torque (Tqmax) and a prevailing torque (Tq); and controlling the torque build-up (s460) so that the resulting torque (Tq) is a function of the continuously determined difference (Tqdiff; Tqdiffnorm). Also a computer program product containing program code (P) for a computer (200; 210; 500) for implementing a method according to the invention. Also a device that performs the method and a motor vehicle (100; 110) equipped with the device are disclosed.