Intake Air Heater Temperature Control to Prevent Over-Temperature Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing intake air heating systems for internal combustion engines face challenges in efficiently controlling the temperature of the air heater, leading to potential over-temperature conditions and increased wear, especially during warm starts when the air heater is warmer than ambient temperature.
Innovation Solution
The system employs an electrical switching device and a control circuit that estimates the temperature of the heater coil by measuring current values, accumulating squared current values, and using a lookup table to modulate the current supply, ensuring the air heater reaches and maintains a desired temperature without exceeding an over-temperature condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the air heater is operated with a fixed time-out control, then the intake air can be heated sufficiently during cold starts, but the air heater may experience over-temperature conditions during warm starts, increasing wear
Solution Approach 1:
The patent implements dynamic control of the air heater by continuously monitoring its temperature and adjusting the duty cycle of the heating element accordingly. The controller modifies the heating power in real-time based on feedback from temperature sensors, transitioning from static fixed-time control to dynamic adaptive control. This resolves the contradiction by allowing sufficient heating during cold starts while preventing over-temperature during warm starts, thereby extending air heater durability.
Solution Approach 2:
The system employs feedback control by using temperature sensors to monitor the air heater temperature and feeding this information back to the controller. The controller then adjusts the heating duty cycle based on the measured temperature to maintain it within desired bounds. This feedback mechanism prevents over-temperature conditions during warm starts while ensuring adequate heating during cold starts, resolving the contradiction between heating effectiveness and component durability.
2Temperature
If the air heater is operated at full power continuously, then the intake air heating is maximized for cold starts, but energy consumption increases and wear is accelerated
Solution Approach 1:
The patent applies periodic action through pulse-width modulation (PWM) control, where the heating element is switched on and off in periodic cycles rather than operating continuously. The duty cycle of these periodic cycles is adjusted based on the required heating level and current air heater temperature. This periodic operation reduces average power consumption compared to continuous full-power operation while maintaining effective heating during cold starts, resolving the contradiction between heating performance and energy consumption.
Solution Approach 2:
The system changes the operating parameters of the air heater dynamically by adjusting the duty cycle percentage based on temperature requirements and ambient conditions. Rather than operating at a fixed parameter (100% power), the controller varies the power level parameter to match the actual heating needs. This parameter adaptation reduces energy consumption when full heating is not required while ensuring adequate temperature rise during cold starts.
3Device complexity
If the air heater temperature is not monitored, then the control system is simpler, but over-temperature conditions occur leading to increased wear and potential damage
Solution Approach 1:
The patent implements feedback control by incorporating temperature sensors that continuously monitor the air heater temperature and feed this information back to the controller. The controller uses this feedback to adjust the heating duty cycle, preventing over-temperature conditions. This feedback mechanism, while adding some complexity, is essential for protecting the air heater and extending its durability, resolving the contradiction between system simplicity and component reliability.
Solution Approach 2:
The system replaces complex mechanical temperature monitoring and control mechanisms with electronic sensing and control circuitry. Modern electronic temperature sensors and microcontrollers provide precise temperature monitoring and control with minimal mechanical moving parts. This substitution achieves reliable temperature control and over-temperature protection while keeping the overall system complexity manageable through electronic rather than mechanical implementation.
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 effectively prevents over-temperature conditions, reduces wear on the air heater, and allows for more precise control of the intake air heating process, ensuring efficient engine starting and reduced emissions.
Implementation Method 1
an electrical switching device configured to selectively connect a battery of the vehicle to a heater coil in contact with intake air of the vehicle
Implementation Method 2
The control circuit is configured to measure a resistance of the heater coil indicative of an initial temperature of the heater coil
Implementation Method 3
The control circuit is configured to estimate the temperature increase by repeatedly measuring a current value of current through the electrical switching device and accumulating a squared value of the measured current values
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An intake air heating system for a vehicle (200) includes an electrical switching device (300) configured to selectively connect a battery (22) of the vehicle to a heater coil in contact with intake air of the vehicle. The intake air heating system includes a control circuit (328) configured to, in response to an enable signal from an engine controller (216), drive the electrical switching device to connect the battery to the heater coil (348) at full current. The control circuit is configured to measure a resistance of the heater coil indicative of an initial temperature of the heater coil and, in response to an estimated temperature of the heater coil exceeding a desired temperature value, modulate the electrical switching device to reduce current from the battery of the vehicle to the heater coil.