Engine Cam Drive Idler Gear Assembly for Compact Packaging
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Solution Overview
Problem
The challenge is to reduce the size of engine components, particularly camshaft pulleys, to fit within limited vehicle spaces while maintaining the desired gear ratio, as direct coupling with crankshafts increases pulley size and overall engine dimensions.
Innovation Solution
The implementation of an idler gear assembly with an idler pulley, where the idler gear is meshed with the crankshaft and rotates slower due to its larger diameter and more teeth, allowing the camshaft pulleys to be coupled to the idler gear via a belt, reducing their size and the engine's overall dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If camshaft pulleys are directly coupled to the crankshaft via a belt, then the gear ratio between the crankshaft and camshafts is maintained, but the size of the camshaft pulleys increases, leading to increased engine height and width
Solution Approach 1:
An idler gear assembly is introduced as an intermediary component between the crankshaft and camshaft pulleys. The idler gear meshed with the crankshaft and the idler pulley coupled to the idler gear, serving as a mediator that transmits rotational motion while enabling smaller camshaft pulley dimensions. This intermediary mechanism allows the belt to contact the idler pulley and camshaft pulleys without requiring large pulley sizes, thus resolving the contradiction between maintaining gear ratio reliability and reducing engine volume.
2Volume of moving object
If the size of camshaft pulleys is reduced to fit within limited vehicle spaces, then the engine packaging is improved, but the gear ratio between the crankshaft and camshafts may be compromised
Solution Approach 1:
The idler gear assembly acts as a mediator that enables small camshaft pulley sizes while maintaining the correct gear ratio. By meshing the idler gear with the crankshaft and coupling the idler pulley to the idler gear, the system achieves the desired angular speed ratio between crankshaft and camshafts without requiring large pulley dimensions, thus resolving the contradiction between compact engine packaging and gear ratio reliability.
Solution Approach 2:
The patent replaces a direct belt-driven mechanical system with a gear-meshed idler assembly. The idler gear meshed with the crankshaft provides a different mechanical transmission path that allows for compact pulley sizes while maintaining the required speed ratio, substituting the conventional direct coupling mechanism with an intermediary gear-based system.
Data Source
AI summary
Methods and systems are provided for a cam drive system of an engine. In one example, a front end of an engine includes an idler gear assembly including an idler gear and idler pulley, the idler gear in meshing engagement with a first end of a crankshaft and the idler pulley coupled to and sharing a rotational axis with the idler gear. The front end of the engine may further include first and second camshaft pulleys positioned vertically above the idler gear assembly and a cam drive belt contacting each of the first and second camshaft pulleys and the idler pulley.