ECU Atmospheric Learning Timing for Exhaust Reducing Fuel

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing internal combustion engine control systems face challenges in accurately and efficiently performing atmospheric learning due to timing issues related to the addition of reducing fuel, leading to missed learning opportunities and potential erroneous learning.

Innovation Solution

The system calculates the total amount of reducing fuel added and oxygen in the exhaust gas, determining when the reducing fuel has decreased to an allowable value, allowing for precise timing of atmospheric learning, and adjusts the learning standby time based on the post-addition time of reducing fuel to minimize waiting periods and ensure accurate learning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reducing fuel is added to exhaust gas, then catalyst reduction is achieved, but oxygen concentration reaches atmospheric level slower causing learning delays

Engineering Contradiction:

Improvecatalyst reduction effectivenessVSAvoidatmospheric learning timing delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The control apparatus calculates the total amount of reducing fuel added in advance before atmospheric learning is performed. By knowing the reducing fuel amount beforehand, the system can determine when the reducing fuel effect has sufficiently dissipated and perform atmospheric learning at the appropriate timing, resolving the conflict between catalyst reduction and learning timing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the oxygen concentration sensor to monitor when the exhaust gas oxygen concentration reaches the atmospheric level. Combined with the calculated reducing fuel amount, this feedback mechanism allows the control apparatus to dynamically determine the optimal learning timing rather than using a fixed delay, thereby resolving the timing conflict.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If a fixed predetermined period is used to prohibit atmospheric learning after reducing fuel addition, then learning accuracy is maintained, but learning opportunities are missed reducing efficiency

Engineering Contradiction:

Improveatmospheric learning accuracyVSAvoidatmospheric learning efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The control apparatus dynamically adjusts the atmospheric learning timing based on the calculated total amount of reducing fuel added. Instead of using a fixed predetermined period, the system flexibly determines when to perform learning by comparing the reducing fuel amount with thresholds, allowing learning to occur as soon as conditions are appropriate rather than waiting for a fixed time period to elapse.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of learning standby time based on the reducing fuel amount. When the reducing fuel amount is small, the standby time is shortened or learning is permitted sooner. When the reducing fuel amount is large, the standby time is extended. This parameter adjustment resolves the contradiction between maintaining accuracy and increasing learning efficiency.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the predetermined period is set low to increase learning efficiency, then more learning opportunities are available, but learning may occur while reducing fuel effects remain causing erroneous learning

Engineering Contradiction:

Improveatmospheric learning efficiencyVSAvoidatmospheric learning accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The control apparatus replaces the mechanical/time-based approach of using a fixed predetermined waiting period with a calculation-based approach. By calculating the total amount of reducing fuel added and comparing it against thresholds, the system substitutes a static time delay with a dynamic determination method that considers the actual reducing fuel quantity, thereby preventing erroneous learning while maximizing efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 learning accuracy and efficiency by ensuring that atmospheric learning occurs at the optimal time, increasing opportunities for learning while maintaining high accuracy even with varying engine states and reducing fuel addition timings.

Implementation Method 1

an oxygen concentration sensor provided in an exhaust passage... a detection signal output from the oxygen concentration sensor is compared with a reference signal value

Methodology Applied

Scientific EffectElectrical conductivity difference: Conduction (electrical)

Data Source

PatentUS8381511B2Internal combustion engine control apparatus and method

Publication Date: 2013.02.26 TOYOTA JIDOSHA KK

AI summary

An ECU performs atmospheric learning to correct an individual difference in an A/F sensor. In this case, when reducing fuel has been added before a fuel cut, the ECU calculates, at fixed intervals, the total amount of reducing fuel added and the total amount of oxygen flowing through an exhaust passage. The ECU then estimates the remaining amount of reducing fuel remaining in the exhaust passage using these total amounts, and performs atmospheric learning when the remaining amount is equal to or less than an allowable value. As a result, atmospheric learning can be accurately performed at the earliest possible timing even if the timing at which the reducing fuel is added or the operating state of an internal combustion engine or the like changes.