Glow Plug Resistance-Based PWM Control for Diesel Engines
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Solution Overview
Problem
The existing methods for controlling glow plugs in diesel engines fail to maintain consistent temperatures across all plugs, leading to variations in ignition behavior and reduced service life due to production-related tolerances and changes in electric resistance over time.
Innovation Solution
A method that determines the electric resistance of each glow plug and calculates a relative pulse width for pulse-width modulation to maintain consistent temperatures, accounting for individual variations in resistance and supply line resistances, ensuring all glow plugs operate at a consistent temperature, thereby improving ignition behavior and extending service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a group of glow plugs is controlled with a common pulse width, then the control system is simple, but temperature variations occur across different glow plugs leading to inconsistent ignition behavior
Solution Approach 1:
The patent segments the control of glow plugs from a common group control into individual control for each glow plug. By determining the electric resistance of each glow plug separately and calculating individual pulse widths based on these resistance values, the system achieves consistent temperatures across all glow plugs while maintaining manageable complexity through automated individualized control.
2Device complexity
If production tolerances and resistance changes are not accounted for, then the control system remains simple, but temperature variations reduce service life
Solution Approach 1:
The patent implements feedback by continuously determining the electric resistance of each glow plug during operation and using this information to adjust the pulse width control parameters. This closed-loop control compensates for production tolerances and resistance changes over time, maintaining optimal operating temperatures and extending service life without requiring overly complex control mechanisms.
Solution Approach 2:
The system dynamically changes the control parameter (pulse width) based on the measured electric resistance of each glow plug. By adjusting the pulse width according to individual resistance values that account for production tolerances and aging effects, the system maintains consistent temperatures and extends the service life of glow plugs.
3Reliability
If individual resistance measurement and control is implemented, then temperature consistency is achieved, but measurement and control complexity increases
Solution Approach 1:
The system uses the glow plugs' own electric resistance as the measurement parameter, which is inherently available during normal operation. By utilizing this self-provided information without requiring external sensors or complex measurement equipment, the system achieves individualized temperature control while minimizing additional complexity.
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 temperature variations, allowing for higher steady-state temperatures, improved ignition behavior, especially in cold-running phases, and extends the service life of glow plugs by accounting for individual resistance changes and production-related tolerances.
Implementation Method 1
determining a value corresponding to an electric resistance of the glow plugs... calculating a relative pulse width at which the glow plugs are to be operated
Data Source
AI summary
Method for controlling a group of glow plugs in a diesel engine, which are connected with a direct current source via individual supply lines and which are to be controlled by a pulse width modulation process at the same temperature, at least in time average. The electric resistance of the glow plugs, less the resistance of the supply line to the heating element of the glow plugs, is determined during operation of the engine and a relative pulse width at which the glow plugs are to be operated is calculated from the value so obtained.