V-type OHV Engine Supercharger Integration and Cooling
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Solution Overview
Problem
Conventional V-type OHV engines with superchargers require an intercooler, making them difficult to miniaturize due to the space constraints created by the intercooler and mechanical supercharger configuration.
Innovation Solution
The use of a gear mechanism for power transmission between the crankshaft and mechanical supercharger, which reduces the engine size by eliminating the need for an intercooler and optimizing the placement of components to minimize space, including offsetting cylinders and the supercharger on the anti-thrust side to decrease friction and size, and incorporating an oil cooling path for efficient cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an intercooler is installed between the two banks to cool supercharging air, then the temperature of intake air is reduced and detonation is prevented, but the engine size increases and miniaturization becomes impossible
Solution Approach 1:
The intercooler is extracted and removed from the engine structure. Instead of installing an intercooler between the banks, the patent uses a different approach by optimizing the supercharger positioning and using the engine's existing cooling system to manage intake air temperature, thereby eliminating the space-consuming intercooler component.
Solution Approach 2:
The cooling function is merged with the engine's existing cooling system rather than adding a separate intercooler. The supercharger is positioned to utilize space within the V-type engine structure, and the cooling air flow is integrated with the engine's natural cooling pathways, combining multiple functions into existing components.
2Power
If a mechanical supercharger is disposed between the two banks, then supercharging function is provided, but the space required for the supercharger and intercooler prevents engine miniaturization
Solution Approach 1:
The mechanical supercharger is nested within the V-type engine structure by positioning it between the two banks in a compact arrangement. The supercharger utilizes the space created by the V-type configuration, fitting into the angular space between cylinders without requiring additional external space, thereby maintaining engine compactness while providing effective supercharging.
Solution Approach 2:
The supercharger positioning utilizes the three-dimensional space of the V-type engine configuration. By arranging the supercharger to exploit the angular space between the V-shaped banks rather than requiring linear space, the design achieves efficient space utilization that enables miniaturization while maintaining supercharging capability.
3Productivity
If the gear mechanism has a high gear ratio to increase supercharger rotation speed, then supercharging efficiency is improved, but the supercharging pressure increases excessively causing temperature increase and detonation
Solution Approach 1:
The gear ratio is optimized to a specific range that balances supercharging efficiency with temperature control. Rather than using an excessively high gear ratio, the patent selects a moderate gear ratio that provides sufficient supercharger rotation speed for effective charging while limiting the pressure and temperature increase to prevent detonation, achieving optimal performance within safe operational parameters.
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 allows for the miniaturization of V-type OHV engines while maintaining high output, reducing supercharging pressure and temperature, and preventing detonation, thereby enabling smaller engine designs without the need for an intercooler.
Implementation Method 1
the power transmission includes a gear mechanism. For a task of changing a given number of rotations of the crank shaft into a desired number of rotations and transmitting the output to the mechanical supercharger, a gear mechanism is more advantageous than a belt mechanism
Implementation Method 2
the gear mechanism has a gear ratio not greater than a predetermined value. When the gear ratio does not exceed a predetermined value, the number of rotations of the mechanical supercharger is controlled. This reduces an increase of the supercharging pressure from the mechanical supercharger, thus reducing a temperature increase of air which enters the engine
Implementation Method 3
incorporating an oil cooling path for efficient cooling
Data Source
AI summary
An OHV engine includes V-shaped banks, a crank shaft, a cam shaft connected to the crank shaft, a mechanical supercharger located between the V-shaped banks, and a power transmission supported by the cam shaft and that connects the crank shaft to the mechanical supercharger. The power transmission includes a gear mechanism with a gear ratio not greater than a predetermined value, and includes a first gear supported rotatably by the cam shaft and that rotates based on an output from the crank shaft, a second gear provided on a rotation shaft of the mechanical supercharger, and an idle gear that connects the first and second gears with each other. Cylinders are offset with respect to a center of the crank shaft on an anti-thrust side of the cylinders, and the mechanical supercharger is also offset with respect to a center of the crank shaft on the anti-thrust side. Cylinder heads are provided with oil cooling paths adjacent respective spark plugs.