Generator Rotor Sensor Cooling Using Crankcase Oil Flow
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Solution Overview
Problem
Existing engine units face challenges in effectively cooling sensors that detect the rotation position of generators, particularly when the generator's operating state results in high temperatures.
Innovation Solution
An engine unit design that includes a coolant passage with an ejection port to direct coolant towards the sensor, utilizing lubricating oil from the crankcase as the coolant, ensuring efficient cooling of the sensor by increasing the surface area of contact and preventing coolant accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is installed to detect rotor rotation position, then measurement precision is improved, but the sensor temperature increases due to generator heat, worsening reliability
Solution Approach 1:
The patent introduces a coolant passage as an intermediary element between the heat source (generator) and the sensor. This passage delivers coolant to directly cool the sensor, acting as a thermal mediator that protects the sensor from excessive heat while maintaining its detection function. The coolant serves as the intermediary substance that transfers heat away from the sensor.
2Reliability
If coolant is supplied to cool the sensor, then temperature is reduced improving reliability, but coolant accumulation may cause water immersion abnormality
Solution Approach 1:
The patent applies local quality by providing coolant only to the specific location where it is needed - the sensor area - rather than flooding the entire generator housing. The coolant passage is designed to target the sensor locally, cooling it effectively while minimizing the volume of coolant in the system and reducing the risk of water immersion abnormalities in other areas.
Solution Approach 2:
The patent uses a hydraulic cooling system where coolant is delivered through a controlled passage to the sensor. This hydraulic approach allows precise control of coolant delivery to the sensor area, ensuring adequate cooling while managing coolant volume and preventing accumulation that could lead to water immersion issues.
3Temperature
If a separate cooling system is added for the sensor, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent merges the sensor cooling function with the existing generator structure by integrating the coolant passage into the generator housing or nearby components. This combination approach allows the sensor to be cooled effectively without adding a completely separate cooling system, thereby reducing overall device complexity while maintaining cooling effectiveness.
Solution Approach 2:
The coolant passage serves multiple functions: it cools the sensor and integrates with the existing generator structure. By designing the passage to utilize existing structural elements, the system achieves multi-functionality where the cooling infrastructure also serves as part of the generator's structural framework, reducing the need for additional dedicated cooling components.
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
The design effectively cools the sensor by increasing the surface area of contact with the coolant, preventing sensor immersion in accumulated coolant, and reducing the risk of abnormality due to water immersion, while also simplifying the cooling system by using existing lubricant passages.
Implementation Method 1
a coolant passage that includes an ejection port, guides a coolant to the ejection port, and ejects the coolant from the ejection port toward the sensor
Data Source
AI summary
An engine unit includes a cylinder, a crankshaft, a crankcase, a generator, a sensor, and a coolant passage. The crankshaft is connected to a piston in the cylinder. The crankcase accommodates the crankshaft therein. The generator includes a rotor that rotates together with the crankshaft and a stator facing the rotor. The generator generates electric power by rotation of the rotor. The sensor detects a rotation position of the rotor. The coolant passage includes an ejection port, guides a coolant to the ejection port, and ejects the coolant from the ejection port toward the sensor.