Evaporative Emission Control Simultaneous Leakage Detection

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Solution Overview

Problem

Conventional evaporative emission control devices in plug-in hybrid vehicles face challenges in efficiently detecting leakage due to reduced internal combustion engine operation, leading to prolonged leakage detection times and increased battery power consumption.

Innovation Solution

An evaporative emission control device with a connecting hole in the canister, a negative-pressure generating unit, a pressure detector, and a leakage judging unit that generates negative pressure in the canister and fuel tank while the tank opening-and-closing unit is open and the communication passage opening-and-closing unit is closed, allowing for simultaneous leakage judgment of the canister and fuel tank.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If leakage detection is performed in two stages (first canister, then fuel tank), then leakage detection accuracy is improved, but leakage detection time is prolonged

Engineering Contradiction:

Improveleakage detection accuracyVSAvoidleakage detection time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines the leakage detection of the canister and fuel tank into a single simultaneous operation. By opening the tank opening-and-closing unit during negative pressure generation, both components are tested together in one cycle, eliminating the need for sequential two-stage detection while maintaining accurate leakage identification through the pressure detector and judging unit

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary preparation by opening the tank opening-and-closing unit before negative pressure generation begins. This ensures that both the canister and fuel tank are already connected and ready for simultaneous detection, eliminating the time required to switch between different detection configurations

Inventive Principle:

Principle #10Preliminary action

2Reliability

If leakage detection is performed in two stages, then comprehensive leakage coverage is improved, but power consumption is increased

Engineering Contradiction:

Improveleakage detection coverageVSAvoidbattery power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges the detection of canister and fuel tank leakage into a single operational cycle. The negative-pressure generating unit operates once to create negative pressure in both components simultaneously, and the pressure detector monitors both together, reducing the cumulative power consumption that would result from two separate detection cycles while maintaining comprehensive leakage coverage

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If the tank opening-and-closing unit is closed during negative pressure generation, then canister leakage detection is improved, but fuel tank leakage detection is prevented

Engineering Contradiction:

Improvecanister leakage detection accuracyVSAvoidfuel tank leakage detection capability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent inverts the conventional approach by keeping the tank opening-and-closing unit open during negative pressure generation instead of closing it. This allows negative pressure to be applied to both the canister and fuel tank simultaneously, enabling both to be tested for leakage at the same time rather than isolating the canister for detection

Inventive Principle:

Principle #13The other way round (Inversion)

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

This solution reduces leakage detection time and power consumption by omitting unnecessary judgments, ensuring accurate detection of leaks without prolonging the process.

Implementation Method 1

a negative-pressure generating unit that generates negative pressure in the canister and the fuel tank through the connecting hole

Methodology Applied

Scientific EffectNegative pressure generation: Depressurisation

Implementation Method 2

a pressure detector that detects internal pressure of the fuel tank or the canister

Methodology Applied

Scientific EffectPressure detection:

Implementation Method 3

a canister interposed in a purge passage connecting the fuel tank and an intake passage of an internal combustion engine... makes the canister absorb the fuel evaporative gas

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS9151251B2Evaporative emission control device for an internal combustion engine

Publication Date: 2015.10.06 MITSUBISHI MOTORS CORP

AI summary

A leakage judgment with respect to a fuel tank is carried out. If the fuel tank is not leaking, a leakage judgment with respect to a canister is carried out. If there is a possibility of leakage in the fuel tank, a leakage judgment with respect to the fuel tank and the canister is carried out. If it is judged that there is leakage in the fuel tank and the canister, the leakage judgment with respect to the canister is carried out.