Internal Combustion Engine Fuel Control Water Detection

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Solution Overview

Problem

Internal combustion engines with capacitance-type alcohol concentration sensors face challenges in accurately distinguishing between water and alcohol presence in fuel, leading to erroneous alcohol detection without proper discrimination means.

Innovation Solution

A control device for internal combustion engines that includes an in-cylinder pressure sensor and an alcohol concentration sensor, using an electronic control unit to calculate a combustion speed parameter based on in-cylinder pressure, determining water presence when capacitance exceeds a threshold and combustion speed is below a preset value, thereby precisely differentiating between water and alcohol.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a capacitance type alcohol concentration sensor is used to detect alcohol in fuel, then alcohol detection capability is improved, but measurement precision deteriorates because water also increases capacitance causing erroneous detection

Engineering Contradiction:

Improvealcohol detection capabilityVSAvoidalcohol concentration measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The detection process is segmented into two independent measurement stages: first measuring capacitance to detect substances with high dielectric constant (alcohol or water), then measuring combustion speed to identify whether it is alcohol or water. This segmentation allows the system to maintain alcohol detection capability while eliminating erroneous detection caused by water contamination.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Combustion speed measurement serves as an intermediary verification step between capacitance detection and final alcohol concentration determination. This intermediary measurement resolves the ambiguity caused by water's similar capacitance effect, enabling precise alcohol concentration measurement even when water is present in the fuel.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If only capacitance measurement is used to detect alcohol, then device complexity is reduced, but measurement precision deteriorates due to inability to distinguish water from alcohol

Engineering Contradiction:

Improvedetection system complexityVSAvoidfuel composition detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The in-cylinder pressure sensor serves multiple functions: its primary function for engine control and a secondary function for measuring combustion speed to detect fuel composition. This multi-functionality allows the system to maintain simple device structure while achieving precise differentiation between water and alcohol in the fuel.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the engine's own combustion process and existing pressure sensing infrastructure to provide fuel composition analysis. The combustion speed measurement leverages the natural combustion phenomenon and the already-installed in-cylinder pressure sensor, eliminating the need for separate dedicated measurement devices and maintaining system simplicity.

Inventive Principle:

Principle #25Self-service

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 allows for precise determination of water in fuel, reducing the concern of erroneous alcohol detection and improving fuel management accuracy.

Implementation Method 1

an in-cylinder pressure sensor configured to detect an in-cylinder pressure that is a combustion pressure within the cylinder

Methodology Applied

Scientific EffectPressure detection:

Implementation Method 2

an alcohol concentration sensor configured to detect capacitance of fuel injected from the fuel injection valve

Methodology Applied

Scientific EffectCapacitance detection: Capacitance

Implementation Method 3

calculate a combustion speed parameter, showing a combustion speed, within the cylinder, of the fuel that is a learning target of the fuel properties, on a basis of the in-cylinder pressure

Methodology Applied

Scientific EffectCombustion speed calculation:

Data Source

PatentUS10087867B2Control device for internal combustion engine

Publication Date: 2018.10.02 TOYOTA JIDOSHA KK

AI summary

A control device for an internal combustion engine is provided. The internal combustion engine includes a cylinder, an in-cylinder pressure sensor, a fuel injection valve, and an alcohol concentration sensor. The control device includes an electronic control unit. The electronic control unit is configured to: carry out learning of fuel properties with the fuel injected from the fuel injection valve as a target; calculate a combustion speed parameter, showing a combustion speed, within the cylinder, of the fuel that is a learning target of the fuel properties, on a basis of the in-cylinder pressure; and determine that water is included in the fuel when the capacitance of the fuel detected by the alcohol concentration sensor is larger than a preset first threshold, and when the combustion speed of the fuel within the cylinder is smaller than a preset second threshold.