Engine Speed Control Torque Feedback Gain

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Solution Overview

Problem

Existing engine rotational speed control systems face challenges in suppressing rotational fluctuations during the transition period between the driven and stopped states of a compressor, particularly due to varying AC load torque, leading to potential engine stall or hyperresponsiveness.

Innovation Solution

An engine rotational speed control apparatus that adjusts torque through feedback corrections, with a larger feedback gain during changeover transition periods to manage AC load torque variations, and sets different execution periods based on load torque convergence properties to prevent hyperresponsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the feedback gain is increased during changeover transition period to suppress rotational fluctuations, then the suppression of rotational fluctuations is improved, but hyperresponsiveness may be caused leading to engine stall

Engineering Contradiction:

Improvesuppression of rotational fluctuationsVSAvoidengine stability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The feedback gain is dynamically adjusted based on the operational state of the compressor. During changeover transition periods, the gain is increased to suppress rotational fluctuations, while during normal operation, the gain returns to standard levels to prevent hyperresponsiveness. This dynamic adjustment resolves the contradiction by applying high gain only when necessary.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system changes the feedback gain parameter according to the compressor's operational phase. By detecting changeover transition periods and temporarily increasing the feedback gain during these specific periods, the system achieves better rotational speed control without causing sustained hyperresponsiveness that would lead to engine stall.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the execution period of changeover transition period control is extended to ensure sufficient convergence of AC load torque, then the suppression of rotational fluctuations is improved, but the system becomes overly responsive after convergence causing engine stall

Engineering Contradiction:

Improveconvergence of AC load torqueVSAvoidexecution period duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The changeover transition period control is applied periodically only during specific transition phases rather than continuously. The control activates during changeover transitions when AC load torque convergence is needed, then deactivates when convergence is achieved, preventing prolonged execution that would cause hyperresponsiveness.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The control system prepares for potential rotational fluctuations by activating changeover transition period control at the onset of compressor state changes. This preliminary action ensures sufficient convergence of AC load torque while limiting the execution period to only when necessary, avoiding extended control that would cause engine stall.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If normal ISC feedback is used during changeover transition period, then the system operates stably under normal conditions, but rotational fluctuations cannot be sufficiently suppressed due to delayed engine torque response

Engineering Contradiction:

Improvesystem stabilityVSAvoidresponsiveness of engine torque

Core Design Contradiction:

Ease of operationVSSpeed

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system anticipates rotational fluctuations during changeover transitions by preemptively increasing the feedback gain before significant speed deviations occur. This preliminary anti-action counteracts the delayed engine torque response by providing stronger corrective feedback in advance, suppressing fluctuations before they become problematic.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS10094315B2Engine rotational speed control apparatus

Publication Date: 2018.10.09 TOYOTA JIDOSHA KK

AI summary

A rotational speed control apparatus for an engine that drives an air conditioning compressor includes an electronic control unit. The electronic control unit corrects a calculated value of a load torque of a compressor in accordance with a deviation between a rotational speed of the engine and a target rotational speed, as a changeover transition period control, in a changeover transition period. The electronic control unit also sets an execution period of the changeover transition period control such that the execution period in a changeover transition period from the stopped state to the driven state of the compressor is longer than an execution period of the changeover transition period control in a changeover transition period from the driven state to the stopped state of the compressor.