Vehicle Idle Speed Controller Synchronization

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Solution Overview

Problem

In vehicle engine control systems, when the processing interval for computing an input signal is longer than the processing interval for computing a feedback amount, the filtered engine speed may not vary with actual engine speed changes, leading to unstable feedback control outputs.

Innovation Solution

A controller is designed with a filtering processing interval equal to the feedback control processing interval, and a time constant for filtering adjusted according to the input signal processing interval, ensuring synchronization and stability of feedback control outputs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the first processing interval (computing input signal) is made longer than the second processing interval (computing feedback amount), then the computing load is reduced and processing efficiency is improved, but the filtered engine speed may not vary with actual engine speed changes leading to unstable feedback control output

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidfeedback control stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies dynamics by making the filtering processing interval variable rather than fixed. The interval is dynamically adjusted to be equal to the feedback amount computing processing interval (second processing interval), ensuring that filtering and feedback control are synchronized. This dynamic adjustment prevents the filtered engine speed from becoming stagnant while maintaining processing efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the filtering processing interval to match the second processing interval. By setting the third processing interval (filtering interval) equal to the second processing interval (feedback amount computing interval), the system ensures that filtering operations occur at appropriate intervals that maintain both efficiency and stability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the filtering processing interval is made equal to the feedback amount computing processing interval, then the filtering and feedback control are synchronized maintaining continuous signal output, but the processing frequency increases leading to higher computing load

Engineering Contradiction:

Improvefeedback control stabilityVSAvoidprocessing efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the filtering processing interval to match the feedback amount computing interval, creating a synchronized operation mode. This ensures that filtering occurs at appropriate moments without unnecessary frequency, maintaining stability while avoiding excessive computing load.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

By synchronizing the filtering processing interval with the feedback amount computing interval, the system ensures continuous and smooth signal flow from filtering to feedback control. This continuity prevents gaps or discontinuities in the control signal while maintaining efficient processing throughput.

Inventive Principle:

Principle #20Continuity of useful action

3Adaptability or versatility

If the time constant of filtering processing is adjusted according to the first processing interval, then the filtering processing adapts to varying processing intervals maintaining proper filtering performance, but the system complexity increases

Engineering Contradiction:

Improvefiltering adaptationVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the time constant parameter of the filtering processing based on the first processing interval. When the first processing interval varies, the time constant is adjusted proportionally to maintain appropriate filtering characteristics. This adaptive parameter adjustment ensures filtering performance remains optimal across different operating conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements dynamic adaptation by making the time constant variable rather than fixed. The time constant is adjusted according to the actual first processing interval, allowing the filtering processing to adapt to changing conditions while maintaining relatively simple implementation through proportional adjustment.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9206750B2Controller for vehicle including computation of a feedback amount based on a filtered input signal

Publication Date: 2015.12.08 DENSO CORP

AI summary

When an idle speed control is implemented, an engine speed is computed based on an output signal of a crank angle sensor at a specified processing angle interval, and a time interval corresponding to the specified processing angle interval is computed. Then, the engine speed is filtered at a specified processing time interval, and a feedback amount (throttle opening correction amount) is computed based on a deviation of an engine speed filtered by a filter portion from a target engine speed. A time constant of a filtering processing is established according to the processing angle interval. Therefore, a filtering processing and a feedback control processing are performed in synchronization with each other, and an instability of an output of the feedback control (feedback amount) can be reduced.