Engine Braking Control via Target Speed and Transmission Ratio

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Engine braking often results in excessive deceleration and energy wastage due to high engine speeds, leading to increased fuel consumption and engine wear, particularly when drivers downshift during braking.

Innovation Solution

A method and powertrain system that control engine speed to a set target value, typically within 30-70 RPM above idle speed, using powertrain components like dual-clutch transmissions or torque converters, to reduce engine speed during braking, thereby minimizing fuel consumption and wear while maintaining vehicle control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If traditional engine braking is applied with high engine speed, then deceleration force is increased, but fuel consumption increases and engine wear increases

Engineering Contradiction:

Improvedeceleration forceVSAvoidfuel consumption

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The patent changes the engine speed parameter from high (traditional engine braking) to low (near idle speed), achieving sufficient deceleration force through optimized transmission ratio selection rather than high engine RPM, thereby reducing fuel consumption and engine wear

Inventive Principle:

Principle #35Parameter changes

2Force

If driver downshifts during engine braking, then deceleration force increases, but engine speed increases excessively causing energy waste

Engineering Contradiction:

Improvedeceleration forceVSAvoidkinetic energy waste

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The patent dynamically selects transmission ratios based on real-time driving conditions and vehicle speed, preventing excessive engine speed increases during gear transitions while maintaining adequate deceleration force, thus avoiding kinetic energy waste

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If engine speed is reduced during engine braking, then fuel consumption decreases, but deceleration force may be reduced

Engineering Contradiction:

Improvefuel consumptionVSAvoiddeceleration force

Core Design Contradiction:

Use of energy by moving objectVSForce

Solution Approach 1:

The patent introduces transmission ratio selection as an intermediary mechanism between engine speed and deceleration force, allowing low engine speed to produce sufficient deceleration through optimized transmission gearing, thus resolving the trade-off between fuel consumption and braking force

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3913205A1Method for engine braking and a powertrain

Publication Date: 2021.11.24 NINGBO GEELY AUTOMOBILE RES & DEV CO LTD

Figure 1
Figure 2
Figure 3

AI summary

The disclosure relates to a powertrain (1) and a method for engine braking of a vehicle (18). The method comprises the steps: - detecting a state indicative of a desired engine braking, - controlling an engine speed to a set engine speed target value by controlling a powertrain component (3) in response to the detected state of a desired engine braking. The powertrain (1) is configured for performing the method.