Glow Plug Voltage Control via Pulse Width Modulation
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Solution Overview
Problem
Glow plugs in diesel engines continue to draw significant electrical power from the vehicle's system when running, causing fluctuations in power demand and potentially destabilizing the vehicle electrical system due to varying engine conditions, especially during irregular engine operation.
Innovation Solution
A method that adjusts the effective voltage applied to the glow plug using pulse width modulation, specifying a target value based on engine speed and limiting voltage changes with a maximum increment to reduce feedback and stabilize the system, thereby minimizing the load on the vehicle electrical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the effective voltage to the glow plug is adjusted immediately to match the target value based on engine speed, then the combustion efficiency is optimized, but the vehicle electrical system experiences unstable feedback and irregular load fluctuations
Solution Approach 1:
The patent applies dynamics by making the voltage control adaptive rather than static. The maximum increment value is not fixed but is determined based on current engine operating conditions (engine speed, load, temperature). This allows the system to dynamically adjust the rate of voltage change to match varying combustion chamber conditions, optimizing combustion efficiency while preventing electrical system instability through condition-based control modulation.
Solution Approach 2:
The patent implements feedback control by continuously monitoring engine parameters (speed, load, temperature) and using this information to determine appropriate voltage adjustment increments. The control system compares the current glow plug voltage with the target voltage and adjusts the voltage in controlled increments based on feedback from engine sensors, thereby achieving stable combustion support without causing electrical system oscillations.
2Productivity
If the glow plug voltage is increased rapidly to meet high engine speed demands, then the combustion performance improves, but the electrical system experiences abrupt load increases and potential instability
Solution Approach 1:
The patent applies beforehand cushioning by implementing a maximum increment limitation on voltage changes. Before allowing the glow plug voltage to increase to meet high engine speed demands, the system pre-limits the rate of voltage rise. This cushioning effect prevents abrupt electrical load spikes by smoothing the voltage transition, thereby protecting the electrical system from harmful fluctuations while still achieving the necessary combustion performance through controlled voltage escalation.
3Reliability
If the glow plug operates at high voltage to maintain temperature during irregular engine running, then the combustion stability is maintained, but the electrical system power demand increases significantly
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the glow plug voltage based on actual engine operating conditions rather than maintaining a fixed high voltage. The control system modifies voltage parameters (magnitude and rate of change) according to sensed engine parameters such as speed, load, and temperature. This allows the system to maintain adequate combustion stability by adjusting voltage to the minimum necessary level rather than continuously applying high voltage, thereby reducing unnecessary electrical power demand.
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 ensures efficient glow plug operation for optimal combustion while reducing unnecessary load on the engine and electrical system by smoothing voltage changes, thus maintaining system stability and efficiency.
Implementation Method 1
an effective voltage is generated from a vehicle electrical system voltage by pulse width modulation
Data Source
AI summary
The method involves generating an effective voltage from a system voltage by pulse width modulation. The effective voltage is applied at a glow plug, and is changed as a function of one or more engine parameters. A nominal value of the effective voltage is specified, where the nominal value depends on the engine parameters. An independent claim is also included for a glow plug control unit.