Engine Speed Control for Dynamic Downshift Events

Solution Overview

Problem

Internal combustion engine fuel efficiency improvements often come at the expense of other performance characteristics, as existing control strategies limit engine speed and load to enhance fuel efficiency, restricting operational ranges and downshift capabilities.

Innovation Solution

A controller system that determines an out-of-gear condition to allow the internal combustion engine to exceed governed speed limits during specific events, such as downshifts, by using a conditions module and permission module to manage engine speed in relation to transmission states and accessory power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If engine speed and load are limited to improve fuel efficiency, then fuel efficiency is improved, but downshift capability and braking performance are worsened

Engineering Contradiction:

Improvefuel efficiencyVSAvoiddownshift capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts engine speed limits based on transmission state. When the transmission is in-gear, engine speed is limited to govern fuel efficiency. When the transmission is out-of-gear (during downshift events), the speed limit is temporarily removed to enable proper downshift capability. This dynamic adjustment resolves the contradiction by making the constraint adaptive rather than static.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The controller changes the engine speed parameter threshold based on operating conditions. The governed engine speed parameter is modified from a fixed value to a conditional value that changes based on transmission engagement state. This allows the system to optimize fuel efficiency during normal operation while enabling high-speed downshift events when needed.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If engine speed is limited to improve fuel efficiency, then fuel efficiency is improved, but braking performance is worsened

Engineering Contradiction:

Improvefuel efficiencyVSAvoidbraking performance

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The system dynamically adjusts engine speed limits based on transmission state. When the transmission is in-gear, engine speed is limited to govern fuel efficiency. When the transmission is out-of-gear (during downshift events), the speed limit is temporarily removed to enable proper downshift capability. This dynamic adjustment resolves the contradiction by making the constraint adaptive rather than static.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system maintains the fuel efficiency benefit by keeping the speed limit in place during normal operation, while temporarily suspending it only when necessary for downshift events. This ensures that fuel efficiency is maintained continuously during most operating conditions, while braking performance is enabled when needed through temporary parameter changes.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS9109521B2Engine speed control

Publication Date: 2015.08.18 CUMMINS INTELLECTUAL PROPERTY INC

AI summary

According to one embodiment, an apparatus for controlling operation of an internal combustion engine includes a conditions module that is configured to determine an out-of-gear condition of the internal combustion engine. The apparatus also includes a permission module that is configured to allow a speed of the internal combustion engine to exceed a maximum engine speed limit if the determined out-of-gear condition meets a threshold, and prevent the speed of the internal combustion engine from exceeding the maximum engine speed limit if the determined out-of-gear condition does not meet the threshold.