Segmented Coolant Jacket for Cylinder Head Ignition Device Cooling
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Solution Overview
Problem
Existing liquid-cooled cylinder heads do not optimally cool the area of greatest heat input between gas exchange outlet valves and the ignition device.
Innovation Solution
The coolant jacket design directs coolant flow from the crankcase, surrounding the gas exchange outlet valves and ignition device, with additional partial jackets merging into the main jacket, ensuring comprehensive cooling and encasing the ignition device's threaded area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional coolant jacket design is used, then the cooling system is simple, but the area of greatest heat input between gas exchange outlet valves and the ignition device is not optimally cooled
Solution Approach 1:
The coolant jacket is divided into multiple partial jackets (first, second, and third partial coolant jackets) that follow different flow paths. The first partial jacket flows between outlet valves and the ignition device, while the second and third partial jackets flow around the outlet valves and merge into the first partial jacket, creating segmented cooling zones that target specific high-heat areas independently
Solution Approach 2:
Different regions of the cylinder head are provided with customized cooling paths based on their specific thermal loads. The first partial jacket provides intensive cooling to the ignition device area, while the second and third partial jackets cool the outlet valve regions, ensuring each component receives appropriate cooling intensity for its functional requirements
2Temperature
If the coolant jacket encloses the ignition device, then heat dissipation is improved, but the manufacturing complexity increases
Solution Approach 1:
The ignition device cooling is achieved through the first partial coolant jacket that flows between the outlet valves and encloses the ignition device and fuel injector. This segmented approach allows the ignition device to be cooled independently through a dedicated flow path without requiring complete redesign of the entire cooling system
Solution Approach 2:
The first, second, and third partial coolant jackets are nested within the cylinder head structure, with the second and third partial jackets merging into the first partial jacket. This nested configuration allows multiple cooling functions to be integrated within a compact space, reducing overall system complexity
3Temperature
If additional partial coolant jackets are added, then cooling homogeneity is improved, but the device complexity increases
Solution Approach 1:
The second and third partial coolant jackets merge into the first partial coolant jacket in the direction of the gas exchange inlet side, creating a unified cooling system. This merging approach allows multiple cooling paths to work together harmoniously, distributing heat more evenly across different regions while maintaining system integration
Solution Approach 2:
The coolant flow paths are designed to address heat generation at its source by directing cooling flow to high-heat areas before excessive heat accumulation occurs. The first partial jacket targets the ignition device and fuel injector areas, while the second and third partial jackets pre-cool the outlet valve regions, preventing thermal hotspots from developing
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 enhances heat dissipation homogeneity, allowing for improved cooling of the cylinder head, even at high performance levels and with less expensive alloys, resulting in cost and consumption advantages.
Implementation Method 1
the coolant flows from the outlet side of the crankcase, coming from the center of the cylinder into the cylinder head and there near the combustion chamber roof between the gas exchange outlet valves and around the ignition device and the fuel injection device
Implementation Method 2
the coolant jacket is designed in such a way that the coolant flow from the outlet side of the crankcase... flows... towards the inlet side
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a coolant jacket (1) for a liquid-cooled cylinder head for an internal combustion engine having a crankcase, wherein the cylinder head has a gas exchange intake side (ES) having two gas exchange intake valves (2) and a gas exchange exhaust side (AS) having two gas exchange exhaust valves (3), wherein a fuel injection valve (4) is provided on the intake side and an ignition device (5) is provided on the exhaust side between the gas exchange valves (2, 3), wherein the coolant jacket (1) extends as a first partial coolant jacket (6) on the exhaust side, coming from the crankcase, between the gas exchange exhaust valves (3) and then radially outside around the ignition device (5) and the fuel injection valve (4) and further in the direction of the intake side (ES) and the crankcase. The optimal cooling of the ignition device and the fuel injection valve according to the invention enables high specific powers and pressures, which leads to a fuel consumption advantage and a cost advantage.