Pulsed Glow Plug Current Control for EMC Reduction
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Solution Overview
Problem
The increasing complexity of electronic components and networking in motor vehicles leads to electromagnetic compatibility (EMC) issues, particularly due to rapid changes in voltage or current from glow plug control systems, causing disturbances in both the vehicle and its environment.
Innovation Solution
The solution involves generating load current pulses that overlap during rising and falling edges, allowing for optimized sequential switching to reduce high-frequency components in the overall supply current, enabling higher frequency switch-on and switch-off phases and improving system efficiency through controlled switching devices and timing control units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If clock control of high glow plug currents is used to adapt temperature behavior and power consumption, then system efficiency is improved, but rapid changes in voltage or current occur causing EMC disturbances
Solution Approach 1:
The patent applies periodic pulsed action to control glow plug currents, switching them on and off at specific frequencies to adapt power consumption while maintaining heating effectiveness. This periodic control allows energy optimization while managing electromagnetic interference through controlled timing of current pulses.
Solution Approach 2:
The patent changes the timing parameters of current pulses to a specific frequency range (3 Hz to 50 Hz, preferably 5 Hz to 20 Hz) to reduce electromagnetic disturbances. By adjusting the frequency and duration parameters of the pulsed currents, the system achieves both energy efficiency and EMC compliance.
2Reliability
If separate power semiconductors are used for each glow plug to enable individual actuation and current monitoring, then individual diagnosis capability is improved, but device complexity increases
Solution Approach 1:
The patent divides the glow plug control system into separate, independently controllable units, with each glow plug having its own power semiconductor switch. This segmentation enables individual monitoring and diagnosis of each plug while maintaining overall system functionality, allowing targeted maintenance without affecting other plugs.
3Use of energy by moving object
If pulse-form load currents with finite edge steepness are fed to glow plugs, then power consumption is controlled, but collapses in overall current occur causing disturbances
Solution Approach 1:
The patent modifies the temporal parameters of current pulses by operating at lower frequencies (3-50 Hz) and optimizing pulse duration and overlap timing. This parameter optimization smooths current transitions and prevents the sharp collapses that cause electromagnetic disturbances, while still maintaining effective power control.
Data Source
AI summary
The present invention concerns a method of and an apparatus for controlling a plurality of load elements in a motor vehicle, wherein corresponding load current pulses for the load elements are so produced that they overlap at least in the region of their rising and falling edges and wherein the configuration in respect of time of the load current pulses is controlled in such a way that a substantially constant overall current is also afforded from the total of the load current pulses of all load elements in the region of the rising and falling edges of the load current pulses.