Engine Temperature Sensor Placement for Cooling Air Interference
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Solution Overview
Problem
Existing engine generators face challenges in accurately measuring engine main body temperature and effectively performing electronic control of fuel injection due to interference from cooling air, which affects fuel efficiency and exhaust gas purification.
Innovation Solution
A general purpose engine configuration that includes a temperature sensor fixed to the engine main body away from the cooling air passage, using a boss part and screw mechanism for secure attachment, allowing accurate temperature measurement and electronic control of fuel injection without cooling air influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a temperature sensor is placed in the cooling air passage to measure engine temperature, then the sensor can detect temperature changes quickly, but the measurement accuracy deteriorates due to cooling air interference
Solution Approach 1:
The patent divides the temperature measurement function into two separate locations: one sensor in the cooling air passage for quick response and another on the engine main body for accurate measurement. This segmentation allows each sensor to fulfill its specific function without interference, resolving the contradiction between detection speed and measurement accuracy.
2Object-generated harmful factors
If electronic control of fuel injection is implemented to improve fuel efficiency and exhaust gas purification, then environmental performance improves, but the system complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The temperature sensor serves multiple functions: it provides data for electronic fuel injection control to improve exhaust gas purification, and simultaneously enables optimization of fuel efficiency. By making the sensor system multi-functional, the patent achieves environmental benefits without proportionally increasing system complexity.
3Temperature
If the cooling cover is designed to guide cooling air along the engine exterior wall for effective cooling, then cooling efficiency improves, but the temperature measurement accuracy deteriorates due to air flow interference
Solution Approach 1:
The patent introduces the engine main body as an intermediary between the cooling air passage and the temperature sensor. The sensor measures temperature on the engine main body rather than directly in the cooling air passage, using the engine structure itself as a mediator to obtain accurate temperature data without direct exposure to cooling air flow interference.
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
Enables high-accuracy temperature measurement of the engine main body and precise electronic control of fuel injection, improving fuel efficiency and exhaust gas purification while reducing costs through shared parts and minimizing interference from cooling air.
Implementation Method 1
a cooling fan (40) that is rotated and driven by the output shaft (22)
Implementation Method 2
a temperature sensor (60) that is fixed to the engine main body (21) in a region away from the cooling air passage (CP)
Implementation Method 3
the cooling cover is fastened by a screw that is screwed into a screw hole of the boss part
Data Source
AI summary
To secure detection accuracy of a temperature sensor in a general purpose engine. A general purpose engine includes an engine main body (21), an output shaft (22) that outputs a rotation force of the engine main body, a cooling fan (40) that is rotated and driven by the output shaft, a cooling cover (50) that is fixed to the engine main body to define a cooling air passage (CP) which guides cooling air generated by the cooling fan along an exterior wall (21e) of the engine main body, and a temperature sensor (60) that is fixed to the engine main body in a region away from the cooling air passage (CP). Accordingly, it is possible to measure a temperature of the engine main body with high accuracy and perform electronic control of fuel injection with high accuracy.