Cylinder Head Sensor Bore Layout for In-Cylinder Pressure Cooling
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Solution Overview
Problem
Existing engine cylinder pressure sensors are exposed to excessive heat from combustion, which can damage them or render their readings inaccurate.
Innovation Solution
The engine cylinder head incorporates a pressure sensor bore that positions the sensor away from hot exhaust passages and adjacent to coolant and lubricant channels, reducing heat exposure through strategic placement and cooling mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pressure sensor is disposed close to the engine cylinder to gauge pressure, then measurement precision is improved, but the sensor is exposed to excessive heat from combustion which can damage the sensor or render it ineffective
Solution Approach 1:
The pressure sensor bore is segmented into multiple sections with different thermal characteristics. The bore includes a first section adjacent to the combustion chamber for pressure sensing, and a second section adjacent to coolant channels for thermal management. This segmentation allows the sensor to be positioned close to the cylinder for accurate measurement while the cooler second section protects the sensor electronics from excessive heat.
Solution Approach 2:
Coolant channels and lubricant channels serve as intermediary cooling mechanisms between the combustion chamber and the pressure sensor. These channels act as thermal mediators that transfer heat away from the sensor, protecting it from direct exposure to combustion heat while still allowing the sensor to measure pressure accurately in the combustion environment.
2Object-affected harmful factors
If the pressure sensor is positioned away from hot exhaust passages, then heat exposure is reduced, but the sensor may be further from the cylinder where pressure measurement becomes less accurate
Solution Approach 1:
The pressure sensor bore is designed with non-uniform thermal properties along its length. The bore has varying wall thicknesses and is positioned to utilize local cooling zones created by coolant and lubricant channels. This local quality variation allows different portions of the bore to serve different functions: closer portions for pressure sensing and cooler portions for thermal protection, optimizing both measurement accuracy and heat exposure reduction.
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 design effectively protects the pressure sensor from excessive heat, ensuring accurate readings and prolonging its operational lifespan.
Implementation Method 1
a coolant channel having a first outer surface including a first portion and a second portion, the first portion being shared with the intake passage and the second portion being shared with the exhaust passage
Implementation Method 2
an in-cylinder pressure sensor (ICPS) bore at least partially defined by at least one wall having at least one second outer surface including a third portion and a fourth portion, the third portion being shared with the coolant channel and the fourth portion being shared with the lubricant channel
Data Source
AI summary
In one instance, an engine cylinder head includes: an intake passage; an exhaust passage; a coolant channel having a first outer surface including a first portion and a second portion, the first portion being shared with the intake passage and the second portion being shared with the exhaust passage; a lubricant channel; and an in-cylinder pressure sensor (ICPS) bore at least partially defined by at least one wall having at least one second outer surface including a third portion and a fourth portion, the third portion being shared with the coolant channel and the fourth portion being shared with the lubricant channel.