Pressure Sensor Diagnosis After Exhaust Pipe Warm-Up

Solution Overview

Problem

Existing vehicle diagnostic devices inaccurately estimate the heat amount and heat dissipation of pressure piping, leading to errors in determining the presence or absence of freezing, which affects the reliability of vehicle diagnostics using pressure sensors.

Innovation Solution

The vehicle diagnostic device permits vehicle diagnostics only after ensuring sufficient warming of the exhaust pipe, using integrated values of vehicle speed and intake air amount to confirm the pressure piping is free of ice, thereby accurately determining the suitability of using a pressure sensor for diagnosis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the vehicle diagnostic device uses estimated received heat amount and heat dissipation amount to determine unfreezing of pressure piping, then the diagnosis can be executed, but the determination accuracy is poor due to large estimation errors

Engineering Contradiction:

Improvediagnosis execution capabilityVSAvoidunfreezing determination accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary warming-up of the exhaust pipe by controlling the engine to operate at conditions that generate sufficient exhaust heat before executing the pressure sensor diagnosis. This preliminary action ensures the pressure piping is free of ice, eliminating the need for complex real-time heat balance calculations and significantly improving the accuracy of unfreezing determination.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the vehicle diagnostic device performs diagnosis using pressure sensor in cold conditions, then the diagnosis can be conducted, but freezing of water in pressure piping may occur causing erroneous diagnosis

Engineering Contradiction:

Improvediagnosis availabilityVSAvoiddiagnosis accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary warming-up of the exhaust pipe by controlling the engine to operate at conditions that generate sufficient exhaust heat before executing the pressure sensor diagnosis. This preliminary action ensures the pressure piping is free of ice, eliminating the need for complex real-time heat balance calculations and significantly improving the accuracy of unfreezing determination.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system proactively prevents freezing by ensuring the exhaust pipe is warmed up before diagnosis is performed. By controlling engine operation to generate sufficient exhaust heat in advance, the system counteracts the potential harmful effect of freezing before it can occur, rather than reacting after freezing has happened.

Inventive Principle:

Principle #9Preliminary anti-action

3Productivity

If the vehicle diagnostic device calculates heat balance in real-time to determine unfreezing, then the diagnosis can be performed, but the calculation complexity and error propagation increase

Engineering Contradiction:

Improvediagnosis execution capabilityVSAvoidheat balance calculation complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The system performs preliminary warming-up of the exhaust pipe by controlling the engine to operate at conditions that generate sufficient exhaust heat before executing the pressure sensor diagnosis. This preliminary action ensures the pressure piping is free of ice, eliminating the need for complex real-time heat balance calculations and significantly improving the accuracy of unfreezing determination.

Inventive Principle:

Principle #10Preliminary action

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 approach enhances the accuracy of vehicle diagnostics by ensuring the pressure piping is sufficiently warmed, preventing erroneous diagnoses due to ice formation.

Implementation Method 1

there will be an environment in which heat of the exhaust pipe after warming up is sufficiently transmitted to the pressure piping

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12553373B2Vehicle diagnostic device

Publication Date: 2026.02.17 TOYOTA JIDOSHA KK

AI summary

A vehicle diagnostic device for diagnosing a pressure sensor, which is used in a vehicle including: an engine mounted on an exhaust pipe with a filter for collecting particulate matter; a pressure piping branching from an upstream side of the filter of the exhaust pipe and bypassing the filter and connecting to a downstream side of the filter; and a pressure sensor mounted on the pressure piping and detecting a pressure of air in the pressure piping, wherein the execution of the diagnosis of the vehicle using the pressure sensor is prohibited, and in a case where freezing of water in the pressure piping is estimated, the execution of the diagnosis of the vehicle using the pressure sensor is permitted when the integrated value of the time traveled at a low speed exceeds the time determination value after the warm-up of the exhaust pipe is completed.