Diesel Engine Starting Control System Glow Plug Timing

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Solution Overview

Problem

In diesel engines, insufficient glow waiting time can lead to unburned gas emissions and poor starting performance due to drivers not waiting for the glow plug to heat sufficiently before starting the engine.

Innovation Solution

A starting control system that compares the actual glow waiting time with the required time and adjusts starting parameters such as main injection timing, common rail pressure, pilot injection amount, pilot injection timing, and target glow temperature to ensure appropriate combustion, even when the glow waiting time is short, by switching between normal and insufficient glow waiting starting constants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the driver switches the engine switch to START before the glow lamp goes out, then the starting operation is expedited, but the glow waiting time becomes insufficient leading to poor combustion and increased emissions

Engineering Contradiction:
Improveglow waiting timeVSAvoidcombustion quality
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The control system dynamically adjusts the starting parameter based on the actual glow waiting time. When the glow waiting time is insufficient, the system switches to a different starting parameter optimized for cold combustion conditions, allowing the system to adapt to varying driver behaviors and environmental conditions rather than using a fixed parameter set

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the starting parameter (such as injection timing, injection quantity, or glow plug energization pattern) based on the comparison between required and actual glow waiting times. This parameter adjustment ensures optimal combustion performance whether the driver waits the full glow period or initiates starting earlier

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the glow waiting time is extended to ensure sufficient heating, then combustion quality improves, but the starting process takes longer

Engineering Contradiction:
Improvecombustion qualityVSAvoidstarting time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system uses dynamic control by comparing the required glow waiting time with the actual glow waiting time and adjusting the starting parameter accordingly. This allows the system to minimize waiting time while ensuring combustion quality by adapting parameters to the actual heating condition achieved

Inventive Principle:
Principle #15Dynamics

3Reliability

If the starting parameter is adjusted for insufficient glow waiting time, then combustion quality improves, but the control system complexity increases

Engineering Contradiction:
Improvecombustion qualityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system manages complexity by implementing a straightforward parameter switching mechanism based on a clear comparison between required and actual glow waiting times. The ECU stores multiple starting parameter sets and selects the appropriate one based on the glow waiting time assessment, providing a manageable control architecture

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates feedback by continuously monitoring the actual glow waiting time and using this information to determine the appropriate starting parameter. This closed-loop approach ensures combustion quality while maintaining simple control logic through clear feedback-based decision making

Inventive Principle:
Principle #23Feedback

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

Ensures smooth engine starting and appropriate fuel combustion even when the glow waiting time is insufficient, reducing emissions and improving starting performance by dynamically adjusting engine parameters based on the time difference between actual and required glow waiting times.

Implementation Method 1

a diesel engine includes a glow plug that is energized and heated

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2535556B1Starting control system for diesel engine
Publication Date: 2021.05.12 TOYOTA JIDOSHA KK
  • EP2535556B1 patent drawingFigure 1
  • EP2535556B1 patent drawingFigure 2
  • EP2535556B1 patent drawingFigure 3

AI summary

In a starting control system for a diesel engine, which performs control of a starting parameter that changes a starting timing of an engine (1), while energizing a glow plug (5) during a period from switching of an engine switch (22) to "Ignition On" to switching to "Starter On", a required glow waiting time as an energization time of the glow plug (5) required for the temperature of the glow plug (5) to increase to a level suitable for starting of the engine (1) is compared with an actual glow waiting time as an actual energization time of the glow plug (5) from switching of the engine switch (22) to "Ignition On" to switching to "Starter On", and the starting parameter is controlled according to a result of the comparison.