Air Flow Rate Measuring Apparatus Heater Cleaning Control
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Solution Overview
Problem
Existing air flow rate measuring apparatuses for internal combustion engines face increased costs due to the need for external determination circuits and dedicated harnesses for heat-cleaning, which can lower measuring accuracy and shorten heater lifespan, especially when implemented at high intake air temperatures.
Innovation Solution
An air flow rate measuring apparatus with a built-in heater and control circuit that temporarily raises the heater's temperature above the measuring mode temperature during startup for heat-cleaning, eliminating the need for external circuits and dedicated harnesses, and controlling the heater temperature to prevent excessive heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat-cleaning is implemented using an external determination circuit and dedicated harness, then the heater can be cleaned, but the configuration cost and power consumption increase
Solution Approach 1:
The patent merges the heat-cleaning function into the existing air flow rate measuring apparatus by integrating the control circuit that manages both measurement and cleaning operations. The control circuit determines when heat-cleaning is needed based on stored program logic, eliminating the need for separate external determination circuits and dedicated harnesses, thus reducing configuration complexity while maintaining the heater cleaning function.
Solution Approach 2:
The control circuit in the air flow rate measuring apparatus is designed to perform multiple functions: it controls the heater for air flow rate measurement and also manages heat-cleaning operations. This multi-functionality eliminates the need for separate external determination circuits, reducing overall system complexity and cost while maintaining effective heater cleaning capability.
2Reliability
If heat-cleaning is implemented at high intake air temperatures, then the heater can be cleaned, but the heater temperature becomes too high causing deterioration
Solution Approach 1:
The control circuit incorporates feedback mechanisms to monitor intake air temperature and heater temperature. Based on this feedback, the control circuit determines whether heat-cleaning should be performed and controls the heater energization to prevent excessive temperature rise. This feedback control ensures the heater reaches appropriate temperatures for cleaning without causing deterioration that would affect measurement precision.
Solution Approach 2:
The control circuit changes operational parameters based on intake air temperature conditions. When intake air temperature is high, the control circuit adjusts the heater energization pattern or duration to achieve effective cleaning without causing the heater temperature to exceed safe limits. This parameter adjustment maintains both cleaning effectiveness and measurement accuracy.
3Reliability
If heat-cleaning is implemented continuously at fuel-cut time, then the heater is cleaned frequently, but the heater deteriorates and measuring accuracy lowers
Solution Approach 1:
Instead of continuous heat-cleaning at every fuel-cut event, the control circuit implements periodic heat-cleaning based on stored program logic that evaluates specific conditions. The control circuit determines appropriate timing for heat-cleaning operations, performing them periodically rather than continuously, which maintains cleaning effectiveness while preventing excessive thermal stress on the heater that would reduce its lifespan.
Solution Approach 2:
The control circuit within the air flow rate measuring apparatus autonomously determines when heat-cleaning is needed based on stored program logic and current operating conditions. This self-service capability eliminates the need for external determination circuits and allows the system to intelligently manage heater cleaning frequency, balancing cleaning needs with heater preservation without requiring continuous intervention.
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 solution reduces configuration and power costs, maintains measuring accuracy by preventing heater deterioration, and efficiently implements heat-cleaning without unnecessary power consumption, ensuring reliable air flow rate measurements.
Implementation Method 1
a heater (2) for heating a part of the intake air sucked into the engine
Data Source
AI summary
An air flow rate measuring apparatus includes a heater and a control circuit. The heater heats a part of an intake air sucked into an engine. The control circuit controls an energization of the heater. The heater has a measuring-mode temperature when a flow rate of the intake air is measured. The control circuit has a heat cleaner which temporarily raises a temperature of the heater higher than the measuring-mode temperature when an energization of the air flow rate measuring apparatus is started.