Engine Speed Control Device with Dual PID Temperature Correction

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Solution Overview

Problem

Existing engine speed control devices struggle to stabilize engine speed in cold states, despite techniques that incorporate temperature corrections, as the operation responsiveness of fuel injection pumps is affected by engine temperature, leading to instability.

Innovation Solution

An engine speed control device that includes detection means for engine speed, cooling water temperature, and lubricating oil temperature, performing PID gain calculations and rack position corrections to produce a rack control signal, enhancing the followability of the fuel injection pump's rack position and stabilizing engine speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If temperature correction factors are applied to PID gains, then engine speed control stability is improved, but the operation responsiveness of the fuel injection pump rack is still affected by cold/hot state, causing disturbance

Engineering Contradiction:
Improveengine speed control stabilityVSAvoidrack operation responsiveness
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The control system is segmented into two independent PID control loops: one for engine speed control and another for rack position control. Each loop has its own PID gains that are separately corrected based on temperature, allowing independent optimization of engine speed stability and rack responsiveness without interference from the other control function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention dynamically changes the PID gain parameters based on engine temperature conditions. Separate correction factors are applied to the first PID gains (for engine speed) and second PID gains (for rack position), allowing the system to adapt control parameters to temperature variations while maintaining optimal responsiveness in both control functions.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a single PID gain correction is applied, then control simplicity is maintained, but engine speed cannot be stabilized in cold state

Engineering Contradiction:
Improvecontrol system complexityVSAvoidengine speed stabilization in cold state
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control system is divided into two independent PID control loops: one for engine speed control and another for rack position control. Each loop has its own PID gains that are separately corrected based on temperature, allowing independent optimization of engine speed stability and rack responsiveness without interference from the other control function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention dynamically changes the PID gain parameters based on engine temperature conditions. Separate correction factors are applied to the first PID gains (for engine speed) and second PID gains (for rack position), allowing the system to adapt control parameters to temperature variations while maintaining optimal responsiveness in both control functions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3633170B1Engine speed control device
Publication Date: 2023.08.02 YANMAR POWER TECH CO LTD
  • EP3633170B1 patent drawingFigure 1
  • EP3633170B1 patent drawingFigure 2
  • EP3633170B1 patent drawingFigure 3

AI summary

An engine speed control device 30 performs: a first PID gain calculation step of calculating a target engine speed Nm to thereby calculate a first PID gain based on an engine speed deviation ΔN between the target engine speed Nm and an engine speed Nr detected by an engine speed detecting means 24; a target rack position calculation step of correcting the first PID gain based on a cooling water temperature Tw detected by a cooling water temperature detecting means 1a to thereby calculate a target rack position Rset of a fuel injection pump 2; a second PID gain calculation step of calculating a second PID gain based on a rack position deviation ΔR between the target rack position Rset and a rack position Rr detected by the rack position detecting means; and a rack control signal producing step of correcting the second PID gain based on a lubricating oil temperature (pump oil temperature Tp) detected by a lubricating oil temperature detecting means to thereby produce a rack control signal Rfset, and the engine speed control device 30 controls an engine speed by controlling a rack position based on the rack control signal Rfset.