Split Oil Pan Layout for Motorcycle Engine Width
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Solution Overview
Problem
Conventional engine layouts with a transmission oil pan positioned below the primary shaft result in an insufficient oil pan capacity when mounted on a straddle-type vehicle, as they require a larger engine width to accommodate the oil pan.
Innovation Solution
The engine design includes a first oil pan for the crankshaft and a second oil pan for the transmission, both separately formed and disposed in parallel with the crankshaft and drive pulley shaft, with the second oil pan extending across the engine's centerline to maintain capacity while minimizing engine width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the oil pan is disposed below the primary shaft that is coaxially disposed on the crankshaft, then the engine structure is simplified, but the engine width increases and the oil pan capacity becomes insufficient
Solution Approach 1:
The patent divides the single oil pan into two separate oil pans: a first oil pan for receiving crankshaft oil and a second oil pan for receiving transmission oil. This segmentation allows each oil pan to be independently positioned and sized, enabling the second oil pan to extend in the vehicle width direction to achieve sufficient capacity without complicating the overall engine structure.
Solution Approach 2:
The second oil pan is configured to extend in the vehicle width direction (lateral dimension) rather than only in the vertical direction below the primary shaft. By utilizing the width dimension, the oil pan achieves sufficient capacity while keeping the engine width minimized for straddle-type vehicle mounting.
2Quantity of substance
If the engine is designed with sufficient oil pan capacity, then the transmission lubrication is adequate, but the engine width increases
Solution Approach 1:
The patent separates the oil storage function into two distinct oil pans, allowing the second oil pan to be specifically optimized for transmission oil capacity. This segmentation enables the oil pan to extend laterally in the vehicle width direction to achieve sufficient capacity without proportionally increasing the overall engine width.
Solution Approach 2:
The second oil pan is specifically designed with extended width to provide sufficient transmission oil capacity, while the first oil pan maintains a compact configuration for crankshaft oil. This local differentiation allows each oil pan to have the appropriate dimensions for its specific function, optimizing overall space utilization.
Data Source
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AI summary
An engine (2) includes: a crankshaft (40), a transmission having a drive pulley and a driven pulley; a first oil pan (110) for receiving oil supplied to the crankshaft (40); and a second oil pan (140), which receives oil supplied to the transmission (60) and is formed separately from the first oil pan (110). The crankshaft (40) extends in a vehicle width direction of a straddle-type vehicle on which the engine (2) is mounted. A drive pulley shaft (62) for driving the drive pulley is disposed parallel to the crankshaft (40). At least a portion of the first oil pan (110) and at least a portion of the second oil pan (140) are respectively disposed in parallel with the crankshaft (40) and the drive pulley shaft (62). The second oil pan (140) has a section extending across the vehicle and engine center lines (C1, C2) in the vehicle width direction.