One-Way Roller Clutch Torque Transfer for Hybrid Engine Starting
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Solution Overview
Problem
Existing internal combustion engine starting systems face durability, noise, vibration, and harshness (NVH) concerns, particularly in hybrid vehicles where frequent engine starting occurs, due to limitations in clutch design, heat generation, efficiency loss, and performance degradation under dynamic movement.
Innovation Solution
A one-way overrunning roller clutch assembly with a drive plate and pinion gear system, featuring a roller clutch with an inner and outer race, rollers, a cage, and a bearing assembly, which allows for selective torque transfer between the starter motor and crankshaft, minimizing oscillatory forces and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clutch is positioned immediately adjacent to or partially within the engine block to utilize existing lubricant, then lubrication is improved, but the positioning becomes limited and requires additional special machining
Solution Approach 1:
A lubricant delivery mechanism acts as an intermediary to transport lubricant from the engine block to the clutch assembly, enabling the clutch to be positioned optimally for torque transfer while maintaining reliable lubrication without requiring complex machining of the engine block
Solution Approach 2:
The lubrication system is segmented into separate components: the engine block lubricant source, a delivery mechanism, and the clutch assembly, allowing independent optimization of each component's position and function
2Adaptability or versatility
If the clutch operates in an overrunning mode to allow engine to drive the starter motor, then adaptability is improved, but heat generation and efficiency loss increase
Solution Approach 1:
The overrunning clutch converts the potentially harmful overrunning condition into a beneficial feature by allowing the engine to freely drive the starter motor generator during compression stroke, transforming what would be energy waste into useful electrical energy generation
Solution Approach 2:
The system changes operational parameters by switching between motor mode (cranking the engine) and generator mode (being driven by the engine), optimizing energy efficiency across different operating conditions
3Adaptability or versatility
If the clutch is designed to handle dynamic movement in radial, axial and angular directions, then adaptability is improved, but performance degradation such as binding increases
Solution Approach 1:
The clutch assembly incorporates dynamic elements including needle bearings that accommodate radial, axial, and angular movements, allowing the clutch to adapt to crankshaft vibrations and dynamic loading while maintaining reliable torque transfer without binding
Solution Approach 2:
Needle bearings act as intermediary elements between the clutch components, absorbing and accommodating dynamic movements in multiple directions while preventing direct contact that would cause binding
4Device complexity
If a retractable pinion electric motor system is used for engine starting, then device complexity is reduced, but durability and NVH performance worsen under frequent starting events
Solution Approach 1:
The system merges the starter motor and generator functions into a single integrated unit, eliminating the need for retractable pinion mechanisms while improving durability and NVH performance through continuous meshed engagement with the flywheel
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
The solution provides a robust torque transfer mechanism that reduces NVH issues, enhances durability, and maintains energy efficiency by effectively managing torque transfer and vibration in hybrid vehicles with frequent engine starting events.
Implementation Method 1
a roller clutch having an inner race adapted to be fixed for rotation with the crankshaft, an outer race fixed for rotation with the drive plate, and a plurality of rollers positioned radially therebetween
Data Source
AI summary
A starting system for a vehicle including an internal combustion engine having a crankshaft includes a pinion gear driven by a starter motor. A drive plate includes a set of teeth in constant meshed engagement with the pinion gear. A one-way clutch assembly is adapted to drivingly interconnect the drive plate and the crankshaft. The clutch assembly includes an inner race adapted to be fixed for rotation with the crankshaft, an outer race fixed for rotation with the drive plate, and a plurality of rollers positioned radially therebetween. One of the inner and outer races includes circumferentially spaced apart cam surfaces. The clutch assembly also includes a cage for positioning the rollers in a circumferentially spaced apart alignment with the cam surfaces and a roller bearing assembly positioned axially offset from the one-way clutch rollers to rotatably support the outer race on the inner race.