Spring-Preloaded Lockup Clutch for Cold-Start Torque Converters
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Solution Overview
Problem
Machines with torque converters face difficulties starting in cold weather due to hydraulic loads, as existing lockup clutch systems require hydraulic pressure to engage, which takes time to build up and further loads the engine, potentially preventing startup in very cold conditions.
Innovation Solution
A spring-preloaded lockup clutch system where a mechanical spring biases a lockup piston to engage with clutch discs in the torque converter, reducing hydraulic load during startup and allowing engagement without waiting for hydraulic pressure to build up, and disengaging once the engine reaches a stable state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic pressure is used to engage the lockup clutch, then the clutch can be engaged and disengaged, but it takes extended time to build up pressure during cold start and adds additional loads to the engine
Solution Approach 1:
The spring is pre-loaded onto the piston before the clutch engagement process begins. This preliminary mechanical pre-loading allows the piston to be in a ready state to engage the clutch discs immediately when needed, eliminating the time delay associated with building hydraulic pressure during cold starts.
Solution Approach 2:
The patent replaces the hydraulic pressure system with a mechanical spring system for the initial clutch engagement during startup. The spring provides the necessary force to engage the clutch discs mechanically without requiring hydraulic pressure buildup, thus substituting a mechanical mechanism for a hydraulic one in the startup phase.
2Reliability
If hydraulic pressure is used to engage the lockup clutch, then the clutch can be engaged, but hydraulic pumps add additional loads to the engine during cold start
Solution Approach 1:
The patent substitutes the hydraulic pump system with a mechanical spring system for clutch engagement during startup. This eliminates the need for hydraulic pumps to operate during cold starts, thereby removing the additional energy load that hydraulic pumps would impose on the engine during the startup phase.
Solution Approach 2:
The invention extracts the hydraulic pump system from the startup engagement process. By using a pre-loaded spring that stores mechanical energy independently, the system removes the dependency on hydraulic pumps during cold starts, thereby extracting the harmful energy-consuming component from the startup sequence.
3Productivity
If a spring-preloaded lockup clutch is used, then startup time is reduced and engine load is decreased, but the system complexity increases
Solution Approach 1:
The patent merges the spring mechanism with the existing hydraulic lockup clutch system. Rather than creating a completely separate system, the spring is integrated into the piston assembly, combining mechanical and hydraulic elements into a unified structure that leverages existing components while adding startup capability.
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 enables faster prime mover startup by reducing hydraulic load and improving starting efficiency, especially in cold conditions, by using a mechanical spring to engage the clutch discs before hydraulic pressure builds up, and disengaging when the engine reaches a stable state, thus reducing engine load and improving starting performance.
Implementation Method 1
a mechanical spring housed in the piston housing and coupled to the lockup piston at the second end of the lockup piston, the mechanical spring operational to bias the lockup piston to engage with the one or more clutch discs
Data Source
AI summary
A spring preloaded lockup clutch system comprises clutch disc(s), an input component, and an output component housed in a hydraulic fluid chamber of a torque converter, a lockup piston and a mechanical spring housed in a piston housing of the torque converter, and a relief valve coupled to the hydraulic fluid chamber. The clutch disc(s), when engaged, couples the input component to the output component. The lockup piston has a first end and a second end, engages with the clutch disc(s) when biased, and disengages from the clutch disc(s) when unbiased. The mechanical spring, coupled to the lockup piston at the second end, applies force to bias the lockup piston. The relief valve, when opened, relieves hydraulic pressure in the hydraulic fluid chamber allowing the lockup piston to remain being biased, and, when closed, allows the hydraulic pressure to build up allowing the lockup piston to be unbiased.