Glow Plug Control Device Temperature Compensation
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Solution Overview
Problem
Modern glow plug control devices face challenges in accurately regulating and maintaining the temperature of glow plugs due to fluctuations in the kILIS factor caused by temperature changes, leading to imprecise current measurement and control.
Innovation Solution
Defining the kILIS factor as a function of temperature and optionally current, using a characteristic curve or calibration data stored in the control device, and incorporating a temperature sensor to adjust the current measurement, allowing for precise temperature control of the glow plug.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed kILIS factor is used in the current measurement circuit, then the device complexity is reduced and ease of manufacture is improved, but the measurement precision deteriorates due to temperature fluctuations during operation
Solution Approach 1:
The patent applies preliminary action by pre-determining and storing multiple kILIS factor values corresponding to different temperature ranges in the control device's memory. During operation, the control device measures the temperature and selects the appropriate pre-stored kILIS factor value, eliminating the need for complex real-time calculations or additional hardware while maintaining high measurement precision across varying temperatures.
2Reliability
If temperature compensation is implemented to improve measurement precision, then the reliability of glow plug temperature control is improved, but the device complexity increases due to additional temperature sensing and calculation requirements
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing correction values or characteristic curves that represent the temperature dependence of the kILIS factor. The control device simply retrieves and applies the appropriate pre-computed values based on measured temperature, avoiding complex real-time physics calculations while achieving reliable temperature-compensated measurements.
Solution Approach 2:
The patent replaces complex mechanical or computational temperature compensation mechanisms with a simplified electronic lookup approach. Instead of implementing complex real-time calculation algorithms or additional hardware compensation circuits, the system uses stored calibration data and simple memory retrieval operations to achieve accurate temperature-compensated current measurements.
3Manufacturing precision
If the kILIS factor is defined as a function of temperature using calibration data, then the manufacturing precision of the measurement system is improved, but the ease of manufacture deteriorates due to additional calibration steps
Solution Approach 1:
The patent applies preliminary action by performing all necessary calibration measurements and kILIS factor determinations during the manufacturing process. The calibrated values are stored in the control device's memory, so that during operation, the device simply uses these pre-established precise values without requiring additional calibration steps in the field, thus achieving high manufacturing precision while maintaining ease of deployment.
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
Enables more accurate current measurement and temperature control of the glow plug by accounting for temperature-dependent kILIS factor changes, improving the precision of heating regulation.
Implementation Method 1
The temperature of a glow plug control device and therefore also the temperature of the current measurement circuit may fluctuate so severely during operation of a motor vehicle that this leads to a noticeable change to the kILIS factor
Implementation Method 2
Pulse-width-modulated voltage pulses are thus generated and applied to a glow plug. The duty cycle of the pulse-width-modulated voltage pulses is adapted by the glow plug control device in relation to the strength of the heating current flowing through the load transistor and the glow plug
Data Source
AI summary
A method for operating a glow plug by means of pulse-width-modulated voltage pulses which are generated by controlling a load transistor, wherein a heating current flowing through the glow plug is measured and the duty cycle of the pulse-width-modulated voltage pulses is changed in accordance with values of the heating current. The heating current can be measured by means of a current measurement circuit, through which a sense current flows parallel to the load transistor, and the value of the heating current is calculated by multiplying a measured value of the sense current by a kILIS factor, wherein the temperature of the current measurement circuit is measured and the kILIS factor is defined in accordance with the measured circuit temperature. A glow plug control device is also disclosed.