Multi-mode Power Train Lock-up Clutch Direct Drive
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Solution Overview
Problem
Existing power train systems for work vehicles lack efficient transition between direct-drive and continuously variable power modes, leading to inefficiencies at high-load/low-speed applications and increased energy loss due to the use of torque converters.
Innovation Solution
A multi-mode power train system with a lock-up device that allows for direct mechanical power transmission between the engine and power-output connection, and an intermediate power-transfer connection for a continuously variable power source, enabling seamless switching between direct-drive and CVP modes without a torque converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a torque converter is used to enable transition between direct-drive and continuously variable power modes, then the system can provide smooth power transmission, but energy loss increases and system efficiency decreases
Solution Approach 1:
The patent removes the torque converter from the power train system entirely, replacing it with a lock-up clutch mechanism that directly couples the engine to the transmission. This extraction of the harmful component eliminates the energy loss associated with torque converters while maintaining the ability to transition between operating modes through the lock-up clutch and continuously variable transmission.
Solution Approach 2:
The patent replaces the fluid-mechanical torque converter with a mechanical lock-up clutch system. The lock-up clutch provides a direct mechanical connection between the engine and transmission, substituting the indirect fluid coupling of a torque converter with a more efficient mechanical coupling that minimizes energy loss while enabling mode transitions.
2Adaptability or versatility
If a torque converter is used for mode transition, then the system can operate in both direct-drive and CVP modes, but device complexity increases
Solution Approach 1:
The patent extracts the torque converter from the system and replaces it with a simpler lock-up clutch mechanism. This reduction in component complexity maintains the multi-mode operational capability while eliminating the inherent complexity of torque converter design, control systems, and fluid coupling mechanisms.
Solution Approach 2:
The patent segments the power transmission path into distinct controllable sections using the lock-up clutch, which can be engaged or disengaged to route power differently. This segmentation allows the system to switch between direct-drive mode (clutch engaged) and CVP mode (clutch disengaged) without requiring a complex torque converter, simplifying the overall system architecture.
3Adaptability or versatility
If the CVP operates over a wide speed range, then the system can adapt to various operating conditions, but the CVP cannot be optimized to a narrow speed range, reducing efficiency
Solution Approach 1:
The patent segments the operating modes into distinct ranges: direct-drive mode for high-speed efficient operation and CVP mode for low-speed/high-torque applications. The lock-up clutch acts as a gatekeeper, directing operation to the most efficient mode for each speed range, allowing the CVP to be optimized for its specific narrow speed range rather than requiring broad-speed-range capability.
Solution Approach 2:
The patent implements dynamic mode switching through the lock-up clutch control system, which automatically transitions between direct-drive and CVP modes based on operating conditions. This dynamic adjustment allows the CVP to operate efficiently within its optimized narrow speed range while the system as a whole adapts to various operating conditions through mode transitions.
Data Source
AI summary
A multi-mode power train and multi-mode vehicle include a power-conversion device that is in communication with an engine via a direct mechanical power-transfer connection extending from the engine to the power-conversion device. A continuously variable power source (CVP) is in communication with the power conversion device via an intermediate power-transfer connection. A lock-up device with first and second engagement states is provided between the engine and the power-conversion device or the CVP. With the lock-up device in the first engagement state, mechanical power from the engine is converted by the power-conversion device for use by the CVP, with the CVP using the converted power to provide mechanical power to a power-output connection. With the lock-up device in the second engagement state, the engine transmits mechanical power through the lock-up device to the power-output connection.