3-Cylinder Engine Layout for Low-Friction Crankshaft and Tilted Oil Control
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Solution Overview
Problem
Existing vehicle engines face challenges in reducing friction in crankshafts, managing coolant flow for temperature control, and preventing oil drainage when the engine is tilted, which affects performance and packaging efficiency.
Innovation Solution
The implementation of a crankshaft assembly with a one-piece crankshaft and specific bearing configurations, an integrated starter-generator for a 4-stroke 3-cylinder engine, a thermostat configuration for coolant management, and an oil tank breathing system with a reed valve to prevent oil drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional crankshaft with multiple pieces and plain bearings is used, then the structure is simpler to manufacture, but friction is higher and engine performance is reduced
Solution Approach 1:
The patent combines multiple crankshaft components into a one-piece crankshaft structure, integrating the crankshaft web and counterweights as a single monolithic component. This merging eliminates the need for separate connecting pieces and reduces the number of bearing assemblies required, thereby reducing friction losses while maintaining structural integrity and engine performance.
Solution Approach 2:
The patent replaces traditional plain bearings with rolling element bearings (ball bearings or roller bearings) at critical locations such as the main bearing journals and rod bearing journals. This substitution transitions from sliding friction to rolling friction, significantly reducing energy loss and improving engine efficiency despite the increased assembly complexity.
2Adaptability or versatility
If the engine is tilted during operation, then vehicle terrain adaptability is improved, but oil drains from the oil tank affecting engine lubrication
Solution Approach 1:
The patent employs a reed valve in the breather line that automatically opens and closes based on pressure differential caused by engine operation and tilt position. The valve self-regulates to maintain vacuum in the crankcase and prevent oil drainage without requiring external control systems, ensuring reliable lubrication across varying terrain conditions.
Solution Approach 2:
The reed valve changes its flow state (open/closed) in response to pressure parameter changes caused by engine operation and vehicle tilt. When the engine tilts, the pressure differential changes cause the reed valve to close, preventing oil from draining out of the breather line and maintaining proper lubrication levels.
3Manufacturing precision
If a complex thermostat configuration with multiple valve plates is used, then coolant flow control precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the thermostat assembly into two separate valve plates (first valve plate and second valve plate) that can move independently or in coordination. This segmentation allows each valve plate to control different coolant flow paths separately, enabling precise control of coolant circulation to the radiator and bypass passages based on engine temperature conditions.
Solution Approach 2:
The thermostat assembly with multiple valve plates serves multiple functions: controlling coolant flow to the radiator, managing bypass flow, and regulating temperature distribution throughout the engine. This multi-functional design achieves precise coolant flow control while consolidating what could be multiple separate control mechanisms into a single integrated assembly.
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
These solutions reduce friction in the crankshaft, enhance engine performance and cold-start behavior, improve coolant flow management for efficient temperature control, and prevent oil drainage when the engine is tilted, thereby simplifying packaging and improving overall engine efficiency.
Implementation Method 1
a first rolling element mounted to the front main bearing journal, a second rolling element mounted to the rear main bearing journal
Implementation Method 2
a reed valve to prevent oil drainage when the engine is tilted
Implementation Method 3
a thermostat configuration, including a main return path formed in a cylinder head of an engine and configured to receive coolant from cylinders of the engine... a thermostat positioned in the thermostat chamber including a first valve plate, a second valve plate and a temperature sensitive element which causes the first valve plate and the second valve plate to move together between opened and closed positions depending upon a temperature of the coolant
Implementation Method 4
a water pump return path configured to deliver coolant to a water pump of the engine
Implementation Method 5
an integrated starter-generator for a 4-stroke 3-cylinder engine, which includes a flywheel including a disk surrounding a central bore configured to receive a crankshaft of the engine and an annular wall extending from a periphery of the disk, the annular wall having a magnetized inner surface, and a stator coaxially disposed within the annular wall of the flywheel, the stator includes a plurality of coils. Upon activation of the integrated starter-generator to start the engine, the plurality of coils are energized to cause the flywheel to rotate, thereby rotating the crankshaft.
Implementation Method 6
a flywheel including a disk surrounding a central bore configured to receive a crankshaft of the engine
Data Source
AI summary
An engine is provided including a crankshaft with an optimized bearing configuration, an integrated starter-generator, an integrated thermostat configured to improve cold start performance, an integrated water system including the integrated thermostat, an integrated oil tank breathing system, and an integrated engine breather system.