Dynamic Cylinder Firing Pattern Selection for Wear Mitigation

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Solution Overview

Problem

Variable displacement internal combustion engines (ICEs) experience uneven cylinder usage, leading to non-uniform wear and tear, resulting in higher repair and failure rates due to the consistent activation and deactivation of specific cylinders during reduced displacement modes.

Innovation Solution

A system and method that generates a running history of cylinder events to select the least-used non-rotating firing pattern for each firing fraction less than one, ensuring even usage among cylinders by alternating multiple defined firing patterns for each reduced displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If non-rotating firing patterns are used for variable displacement operation, then fuel efficiency is improved through reduced displacement, but uneven cylinder usage occurs leading to increased wear and tear

Engineering Contradiction:

Improvefuel efficiencyVSAvoidcylinder wear uniformity

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies dynamics by transitioning from static non-rotating firing patterns to dynamic rotating firing patterns. The engine controller dynamically selects and switches between different firing patterns based on operating conditions, ensuring that different cylinder groups are activated at different times. This dynamic approach maintains fuel efficiency through reduced displacement operation while distributing wear more uniformly across all cylinders over time.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements periodic action through rotating firing patterns that systematically cycle through different cylinder groups. Instead of continuously activating the same cylinders, the system periodically switches between different firing patterns (e.g., activating cylinders 1-3 in one pattern, then cylinders 2-4 in the next pattern). This periodic rotation ensures that no single group of cylinders is overused, thereby reducing uneven wear while maintaining the fuel efficiency benefits of variable displacement.

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If the same group of cylinders is continually activated at reduced displacement, then fuel efficiency is improved, but repair and failure rates increase due to non-uniform wear

Engineering Contradiction:

Improvefuel efficiencyVSAvoidrepair and failure rates

Core Design Contradiction:

Use of energy by moving objectVSEase of repair

Solution Approach 1:

The system dynamically switches between multiple firing patterns rather than continuously using one static pattern. The engine controller monitors operating conditions and rotates through different firing patterns, ensuring that different cylinder groups are activated during different time periods. This dynamic pattern rotation maintains the fuel efficiency of reduced displacement operation while preventing any single cylinder group from suffering excessive wear that would lead to higher repair and failure rates.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies the discarding and recovering principle by temporarily deactivating certain cylinder groups during specific operating periods, then rotating to activate different groups. Instead of continuously using the same cylinders, the system discards (deactivates) one group while using another, then periodically swaps their roles. This rotation allows previously deactivated cylinders to recover from wear, thereby reducing overall repair and failure rates while maintaining fuel efficiency during active periods.

Inventive Principle:

Principle #34Discarding and recovering

3Device complexity

If non-rotating firing patterns are used, then device complexity is reduced, but uneven usage of cylinders and valves occurs

Engineering Contradiction:

Improvefiring pattern controlVSAvoidcylinder usage uniformity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the firing patterns into multiple distinct, predefined patterns (e.g., Pattern A activates cylinders 1-3, Pattern B activates cylinders 2-4, etc.). Each pattern is a separate, manageable segment that can be independently controlled. The engine controller selects and rotates between these segmented patterns, which simplifies the control logic compared to complex real-time calculations while still achieving uniform cylinder usage over time through systematic pattern rotation.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20230392561A1Non-rotating cylinder pattern selection for equalizing cylinder usage in an internal combustion engine

Publication Date: 2023.12.07 TULA TECHNOLOGY INC

AI summary

A system and method for operating an ICE by (a) generating a running history of one or more-cylinder events per cylinder, and (b) using the running history to select a least-used non-rotating firing pattern, among a plurality of non-rotating firing patterns, provided for each firing fraction less than one (1). By making the least used selection based on the running history, unequal usage among cylinders of the ICE can be mitigated.