Hybrid Vehicle Creep Control for Engine-Electric Mode Consistency

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Solution Overview

Problem

Hybrid vehicles experience inconsistent vehicle creep behavior when transitioning between engine-driven and electric-driven modes due to the absence of a torque converter in electric powertrains, making it difficult for drivers to anticipate vehicle movement on gradients.

Innovation Solution

A control system that uses a mathematical model to replicate engine creep torque by controlling the electric traction motor to provide tractive torque to the vehicle wheels, ensuring consistent vehicle behavior by simulating the behavior of a torque converter, including automatic speed adjustments based on slope and environmental conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a torque converter is used in engine-driven mode to provide vehicle creep, then the vehicle moves forward automatically at idle, but the creep behavior is inconsistent when transitioning to electric-driven mode

Engineering Contradiction:

Improvevehicle creep behavior consistencyVSAvoidoperating mode flexibility

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent applies the copying principle by using a mathematical model to replicate the torque converter's creep behavior in electric-driven mode. The control system calculates and applies an equivalent creep torque that mimics the physical torque converter's characteristics, ensuring consistent vehicle behavior across different operating modes without requiring a physical torque converter in both paths.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical torque converter system with an electrical control system that uses mathematical modeling. Instead of relying on the physical torque converter's fluid dynamics to create creep in electric mode, the system substitutes a computational model that calculates the appropriate creep torque to achieve the same effect, thereby unifying the creep behavior across engine and electric operating modes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of energy

If the torque path between engine and wheels is disconnected during electric driving, then fuel consumption and emissions are reduced, but vehicle creep behavior becomes unpredictable

Engineering Contradiction:

Improvefuel consumptionVSAvoidvehicle movement predictability

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

When the torque path is disconnected during electric driving, the system copies the torque converter's creep characteristics through a mathematical model. This allows the vehicle to maintain predictable creep behavior similar to engine-driven mode while keeping the mechanical connection断开, thereby reducing parasitic losses and improving fuel efficiency without sacrificing operational predictability.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The mathematical model acts as an intermediary between the electric traction motor and the vehicle wheels, providing the missing creep function that would otherwise require a physical torque converter. This intermediary calculation layer enables the system to achieve both energy efficiency (by disconnecting the torque path) and operational predictability (by replicating creep behavior through computation).

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution provides consistent vehicle behavior across both engine-driven and electric-driven modes, replicating torque converter behavior by automatically slowing or speeding the vehicle based on slope and environmental conditions, ensuring smooth transitions and improved driver experience.

Implementation Method 1

control the electric traction motor to provide tractive torque to a second set of vehicle wheels

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

electric vehicle creep is controlled by a mathematical model of engine creep torque that would be provided by the engine

Methodology Applied

Scientific EffectMathematical modeling:

Data Source

PatentUS12128870B2Hybrid vehicle creep control

Publication Date: 2024.10.29 JAGUAR LAND ROVER LTD

AI summary

A method and a control system for controlling movement of a vehicle to provide vehicle creep, the vehicle having an engine and an electric traction motor, and the control system having one or more controllers. The control system is configured to: while a torque path between the engine and a first set of vehicle wheels is disconnected, control the electric traction motor to provide tractive torque to a second set of vehicle wheels to automatically move the vehicle to provide electric vehicle creep. The electric vehicle creep is controlled by a mathematical model of engine creep torque that would be provided by the engine when the torque path between the engine and the first set of vehicle wheels is connected.