Glow Plug Temperature Control via Feedback Energy Balance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing control systems for glow plugs in internal combustion engines either damage the plugs due to overvoltage or fail to maintain stable temperature under varying engine conditions, leading to inefficient preheating and thermal stress.

Innovation Solution

A closed-loop feedback control system that estimates the temperature of the glow plug using an energy balance model, adjusting the electrical power supplied based on the difference between the estimated and objective temperatures to ensure precise and stable heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If overvoltage is supplied to the glow plug to reduce preheating time, then the preheating time is reduced, but the glow plug may be damaged due to excessive thermal stress

Engineering Contradiction:

Improvepreheating timeVSAvoidglow plug durability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent implements a feedback control system that continuously monitors the actual glow plug temperature and compares it with the target temperature. Based on this comparison, the control system adjusts the electrical power supplied to the glow plug in real-time, preventing overvoltage damage while ensuring rapid preheating when needed.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control system dynamically adjusts the electrical power supply to the glow plug based on real-time temperature conditions. The system transitions from static fixed-power supply to dynamic variable-power supply, adapting the heating rate to the actual thermal state of the glow plug and combustion chamber.

Inventive Principle:

Principle #15Dynamics

2Loss of time

If open loop electronic control systems are used to boost supply voltage, then preheating time is reduced, but the system fails to maintain stable plug temperature under varying engine conditions

Engineering Contradiction:

Improvepreheating timeVSAvoidplug temperature stability

Core Design Contradiction:

Loss of timeVSStability of the object's composition

Solution Approach 1:

The patent employs a closed-loop feedback control system that continuously measures the actual glow plug temperature and adjusts the electrical power supply accordingly. This feedback mechanism enables the system to maintain stable plug temperature despite variations in engine operating conditions, fuel properties, and environmental factors.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the open-loop electronic control system with a closed-loop control system that uses temperature sensing and feedback mechanisms. This substitution transforms the control approach from predetermined fixed-pattern heating to adaptive real-time temperature-regulated heating.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Extent of automation

If self-regulating glow plugs with internal varistor are used, then automatic temperature regulation is achieved, but temperature dispersion increases under various engine operating conditions

Engineering Contradiction:

Improveautomatic temperature regulationVSAvoidtemperature consistency

Core Design Contradiction:

Extent of automationVSStability of the object's composition

Solution Approach 1:

The patent implements an external feedback control system that directly measures the glow plug temperature and adjusts the electrical power supply in real-time. This external feedback mechanism provides more precise temperature control compared to the internal self-regulation mechanism, reducing temperature dispersion under varying engine conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control system dynamically changes the electrical power supply parameters (voltage, current, power) based on the measured temperature and desired temperature profile. This enables precise control of the heating process, maintaining temperature consistency across different engine operating conditions.

Inventive Principle:

Principle #35Parameter changes

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 reduces preheating time while maintaining stable glow plug temperature across various engine conditions, enhancing engine performance without the need for direct temperature sensors, thus avoiding overvoltage damage and thermal stress.

Implementation Method 1

a supply voltage is supplied to the glow plug so to bring the temperature of the latter to a value equal to an objective temperature

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

heat the combustion chambers and the operating fluid in these chambers

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

heat the combustion chambers and the operating fluid in these chambers

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS7528346B2Internal combustion engine provided with a heating device in a combustion chamber and a control method for the heating device

Publication Date: 2009.05.05 MAGNETI MARELLI POWERTRAIN S P A

AI summary

An internal combustion engine comprising at least one cylinder provided with at least one glow plug adapted to heat a variable volume combustion chamber within the cylinder, and an electronic control unit which in turn comprises an estimation module adapted to estimate the temperature of the glow plug within the combustion chamber and a control module which is adapted to drive the glow plug as a function of the estimated temperature.