Internal Combustion Engine Cooling Structure for Exhaust Collection Portion
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Solution Overview
Problem
In internal combustion engines with exhaust collection portions formed inside the cylinder head, the large exposed area leads to excessive temperature increases, necessitating effective cooling to prevent overheating, particularly around the exhaust collection portion.
Innovation Solution
A cooling structure featuring a cylinder block with an inner-block coolant passage and a cylinder head with an inner-head coolant passage, including a main coolant passage and separate upper and lower exhaust side coolant passages that circulate coolant in a unidirectional manner to uniformly cool the combustion chambers and exhaust collection portion, with the upper exhaust side coolant passage surrounding exhaust valve guide portions and having a larger cross-sectional area on the upstream side to facilitate coolant flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the exhaust collection portion is formed inside the cylinder head to reduce engine size and improve response, then the engine size is reduced and response is improved, but the exposed area increases causing excessive temperature rise
Solution Approach 1:
The coolant passage system is segmented into multiple independent passages: a main coolant passage for general cooling and separate first/second exhaust side coolant passages for targeted cooling of the exhaust collection portion. This segmentation allows independent control of coolant flow to different thermal zones, enabling effective cooling of the high-temperature exhaust collection area without compromising overall engine cooling efficiency.
Solution Approach 2:
Different cooling strategies are applied to different regions: the main coolant passage provides general cooling, while the first exhaust side coolant passage specifically targets the exhaust collection portion with higher coolant flow. The passage cross-sectional areas are optimized locally - the first exhaust side coolant passage has a larger cross-sectional area to increase coolant flow rate to the high-temperature exhaust region, implementing local quality adjustment to match thermal demands.
2Temperature
If water flows in a direction orthogonal to cylinder row direction to cool the exhaust manifold, then cooling coverage is improved, but coolant distribution becomes complex and uniform cooling is difficult to achieve
Solution Approach 1:
The coolant distribution system is divided into separate functional passages: the main coolant passage handles general cooling with simple linear flow, while the first and second exhaust side coolant passages independently handle exhaust collection portion cooling. This segmentation simplifies each individual passage design while achieving comprehensive cooling coverage through their coordinated operation.
Solution Approach 2:
Instead of using a single complex passage attempting to cool all regions uniformly, the invention inverts the approach by using multiple simple passages, each dedicated to a specific region. The exhaust side coolant passages draw coolant from the main passage and deliver it specifically to the exhaust collection portion, reversing the traditional single-passage-multi-region approach for better simplicity and control.
3Length of moving object
If the exhaust collection portion is formed inside the cylinder head, then the distance from combustion chambers to exhaust outlet is shortened, but the area requiring cooling increases
Solution Approach 1:
The cooling system is segmented into a main coolant passage for the general cylinder head region and separate first/second exhaust side coolant passages specifically for the exhaust collection portion. This segmentation ensures that the increased exposed area of the compact exhaust collection portion receives dedicated cooling attention through the exhaust side passages.
Solution Approach 2:
The cooling strategy applies local quality by providing enhanced cooling specifically to the exhaust collection portion through the first exhaust side coolant passage with larger cross-sectional area, while other regions receive appropriate cooling through the main passage. This matches the cooling capacity to the local thermal demands created by the compact exhaust design.
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 configuration ensures uniform coolant flow rates around the cylinders, effectively cools the exhaust collection portion, and simplifies coolant distribution, reducing the risk of overheating and improving engine performance.
Implementation Method 1
The inner-head coolant passage includes a main coolant passage formed in a portion above the combustion chambers, and a pair of upper and lower exhaust side coolant passages that are formed so as to interpose the exhaust collection portion
Data Source
AI summary
A cooling structure of an internal combustion engine includes a cylinder block, an inner-block coolant passage, a cylinder head, and an inner-head coolant passage. In the cylinder block, cylinders are provided in a row in a cylinder row direction. The inner-head coolant passage is provided in the cylinder head and includes a main coolant passage, an upper exhaust side coolant passage, and a lower exhaust side coolant passage. The main coolant passage is provided above combustion chambers and extends in the cylinder row direction so that a coolant flows into the main coolant passage from the inner-block coolant passage at a first end side of the cylinder head in the cylinder row direction and so that the coolant flows out from the main coolant passage at a second end side of the cylinder head opposite to the first end side in the cylinder row direction.