Purge Pipe Leakage Detection in Supercharged Engines

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Solution Overview

Problem

Existing technologies do not effectively detect abnormalities in the purge pipe of an internal combustion engine with a supercharger, leading to potential evaporation fuel leakage, as they lack a specific configuration for diagnosing issues related to the purge pipe's connection with the intake pipe upstream of the supercharger.

Innovation Solution

An abnormality detection device is implemented, featuring a canister to absorb evaporation fuel, a purge pipe connected upstream of the supercharger, a switching unit to control the purge pipe, and an abnormality detection unit that uses differential pressure between the intake pipe-side pressure and a reference pressure to detect leakage, ensuring accurate detection during specified operation conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the purge pipe is connected to the intake pipe downstream of the supercharger, then the structure is simpler, but the evaporation fuel cannot be purged during supercharging operation due to positive pressure

Engineering Contradiction:

Improvepurge system configurationVSAvoidevaporation fuel circulation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The intake pipe is divided into two functional zones: upstream of the supercharger (negative pressure region) and downstream of the supercharger (positive pressure region). The purge pipe is specifically connected to the upstream side to ensure proper evaporation fuel circulation during supercharging operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the intake pipe are assigned different functional qualities based on pressure characteristics. The upstream region near the throttle valve is designated as the purge connection point due to its consistent negative pressure, while the downstream region handles compressed air supply.

Inventive Principle:

Principle #3Local quality

2Reliability

If the purge pipe is connected to the intake pipe upstream of the supercharger, then evaporation fuel can be purged during supercharging, but the connection position is more restricted

Engineering Contradiction:

Improveevaporation fuel circulationVSAvoidpurge system configuration

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Device complexity

If pressure sensing is performed during normal operation, then the system is simpler, but leakage cannot be accurately detected due to varying pressure conditions

Engineering Contradiction:

Improvedetection systemVSAvoidleakage detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary isolation of the purge pipe using the switching valve before leakage detection. By closing the purge valve and isolating the pipe section, the system creates stable pressure conditions that enable accurate leakage detection regardless of engine operating state.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from pressure sensor readings to determine whether leakage is present. The ECU continuously monitors pressure changes in the isolated purge pipe and compares them against threshold values to accurately diagnose leakage conditions.

Inventive Principle:

Principle #23Feedback

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 device accurately detects leakage occurrences in the purge pipe by measuring differential pressure, preventing fuel loss and maintaining engine efficiency, even during supercharging operations.

Implementation Method 1

a pressure sensor that senses a pressure in the purge pipe

Methodology Applied

Scientific EffectPressure:

Implementation Method 2

an abnormality detection unit to detect a leakage occurrence of the purge pipe based on a differential pressure between an intake pipe-side pipe pressure (BA) and a reference pressure

Methodology Applied

Scientific EffectDifferential pressure:

Data Source

PatentUS10151274B2Abnormality detection device for internal combustion engine

Publication Date: 2018.12.11 DENSO CORP

AI summary

An abnormality detection device of an internal combustion engine includes an ECU that is an abnormality detection unit detecting a leakage occurrence of a second pure pipe. When the internal combustion engine is in a supercharging operation state that a supercharger operates and the second purge pipe is closed by a second purge valve, the ECU detects the leakage occurrence of the second purge pipe based on a differential pressure between a pressure in the second purge pipe and an atmospheric pressure. In this case, the valve pressure in the second purge pipe is a pressure in the second purge pipe between the second purge valve and the intake pipe.