Engine Fuel Injection Control for Unauthorized Intake Modification Detection

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Solution Overview

Problem

Existing control systems fail to detect and prevent output exceeding legal limits in internal combustion engines due to unauthorized modifications, such as replacing air funnels, as they rely solely on oxygen sensor feedback for air-fuel ratio maintenance.

Innovation Solution

A control apparatus that utilizes multiple sensors to monitor intake and exhaust parameters, including oxygen sensors, throttle position, and engine speed, to identify unauthorized modifications by adjusting fuel injection based on correction coefficients and threshold values, restricting output when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If oxygen sensor feedback control is used to maintain target air-fuel ratio, then fuel injection control precision is improved, but ability to detect unauthorized intake system modification is deteriorated

Engineering Contradiction:
Improveair-fuel ratio control precisionVSAvoidmodification detection capability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent divides the monitoring function into two independent parts: oxygen sensor feedback for air-fuel ratio control, and additional sensors (intake flow sensor, exhaust gas flow sensor) for modification detection. This segmentation allows each system to perform its specific function without interfering with the other, resolving the contradiction between control precision and detection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate sensors (intake flow sensor, exhaust gas flow sensor) that act as mediators between the engine system and the control unit. These sensors provide additional information about system modifications without disrupting the existing oxygen sensor feedback control, enabling detection while maintaining control precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If fuel injection amount is controlled by oxygen sensor feedback, then emission control is improved, but output limitation enforcement is deteriorated

Engineering Contradiction:
Improveemission controlVSAvoidoutput limit compliance
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent implements a dual feedback mechanism: oxygen sensor feedback for emission control and additional sensor feedback (intake flow, exhaust gas flow) for output limitation enforcement. The control unit processes both feedback streams independently, allowing emission control and output limit compliance to be maintained simultaneously through coordinated control actions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent monitors changes in operational parameters (intake flow rate, exhaust gas flow rate) that indicate unauthorized modifications. When these parameters deviate from expected ranges, the control unit adjusts fuel injection amount to maintain output within legal limits, thereby enforcing output restrictions while preserving emission control through continued oxygen sensor feedback.

Inventive Principle:
Principle #35Parameter changes

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

Effectively prevents output exceeding legal limits by detecting unauthorized modifications and restricting engine performance, ensuring compliance with legal regulations while maintaining normal operation.

Implementation Method 1

an oxygen sensor is provided in an exhaust passage, and the fuel injection amount is set such that a target air-fuel ratio is maintained by feeding back a detection result of the oxygen sensor

Methodology Applied
Scientific EffectOxygen sensing:

Data Source

PatentEP3533986B1Control apparatus
Publication Date: 2026.04.22 HONDA MOTOR CO LTD
  • EP3533986B1 patent drawingFigure 1
  • EP3533986B1 patent drawingFigure 2
  • EP3533986B1 patent drawingFigure 3A~3C

AI summary

A control apparatus includes a control means configured to control a fuel injection amount of an internal combustion engine, and an oxygen sensor provided on an exhaust passage of the internal combustion engine. The control means can control the fuel injection amount so as to be maintained at a predetermined air-fuel ratio by correcting, based on a detection result of the oxygen sensor, a basic value based on an operating state of the internal combustion engine. The control means restricts an output of the internal combustion engine when an increase of correction based on a detection result of the oxygen sensor becomes equal to or larger than a predetermined rate with respect to the basic value.