Engine Camshaft Transmission Segmentation for Torque and Mass
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Solution Overview
Problem
Existing transmission solutions for internal combustion engines, such as gears, chains, and toothed belts, face challenges in efficiently transmitting high torque between the crankshaft and camshaft, leading to increased size and mass of components, which limits the proximity of camshafts and restricts the choice of accessories that can be driven, and none of these solutions are entirely satisfactory.
Innovation Solution
An assembly comprising a chain or toothed belt with two intermediate toothed wheels, where the first intermediate toothed wheel is meshed with the crankshaft toothed wheel, and the chain or toothed belt is meshed with the second intermediate toothed wheel, which is integral with the camshaft toothed wheel, allowing for independent sizing of components and reduced torque transmission, thereby reducing the bulk and mass of the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a chain or toothed belt is used to transmit high torque from the crankshaft to the camshaft, then the torque transmission capability is improved, but the size and mass of the chain or belt increase, leading to increased sprocket dimensions and mass
Solution Approach 1:
The transmission system is divided into two separate paths: a first chain or toothed belt for transmitting high torque to rotate the camshaft, and a second chain or toothed belt for rotating the balance shaft. This segmentation allows each chain to be optimized for its specific torque requirements, reducing the overall size and mass of the transmission components while maintaining the necessary torque transmission capability.
2Force
If the number of teeth and diameter of crankshaft and camshaft sprockets are increased to transmit high torque, then the torque transmission capability is improved, but the proximity between two camshafts is limited
Solution Approach 1:
The transmission system is segmented into two independent chains with separate sprockets. The first chain connects the crankshaft to the camshaft with appropriately sized sprockets for high torque transmission, while the second chain connects the crankshaft to the balance shaft. This segmentation allows the camshafts to be positioned closer together since the high-torque transmission requirements are met by the first chain without requiring oversized sprockets that would interfere with camshaft proximity.
3Area of moving object
If one camshaft is rotated with a chain or toothed belt and the second camshaft is rotated with gears via the first camshaft, then the size of camshaft sprockets is reduced, but the overall length of the camshafts is significantly increased
Solution Approach 1:
Instead of using a gear train that would require extending the camshaft length, the invention segments the transmission system by introducing a second independent chain or toothed belt that directly connects the crankshaft to the balance shaft. This eliminates the need for long gear trains and allows for more compact camshaft positioning while maintaining adequate sprocket sizes for reliable torque transmission.
4Reliability
If gears are used to transmit rotational motion from the crankshaft to the camshaft, then the transmission reliability is improved, but the device complexity increases, especially when the distance between crankshaft and camshaft is significant
Solution Approach 1:
The transmission system is segmented into two separate chain or toothed belt drives instead of using a complex gear train. This segmentation simplifies the overall device complexity by using straightforward belt/chain transmission for each function, while maintaining reliability through the direct transmission paths. The first chain handles high-torque camshaft rotation and the second chain handles balance shaft rotation, eliminating the need for complex intermediate gear mechanisms.
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 solution allows for adaptable camshaft arrangement, reduced component size, and compatible torque transmission, enabling the internal combustion engine to efficiently handle accessories with varying torque requirements while minimizing bulk and mass.
Implementation Method 1
a first intermediate toothed wheel (21) meshed with a crankshaft toothed wheel (12), while a chain or toothed belt (24) is meshed with a second intermediate toothed wheel (23), which is integral with a camshaft toothed wheel (15, 16)
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an assembly (10) for an internal combustion engine, in particular for a motor vehicle, comprising a crankshaft (11), a crankshaft gear (12) mounted rotationally fixed on the crankshaft, at least one camshaft (13, 14), a camshaft gear (15, 16) mounted rotationally fixed on the camshaft and a transmission element (17) itself comprising: - a first intermediate gear (21) meshed with the crankshaft gear, - a second intermediate gear (23) mounted rotationally fixed with the first intermediate gear (21), - a closed flexible transmission element (24) meshed on one side with the second intermediate gear and on the other side with the camshaft gear.