Variable-Pitch Torque Converter for Dynamic K-Factor Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing torque converters lack the ability to dynamically adjust their K-factor to optimize performance across different operating conditions, often requiring a compromise between engine efficiency at lower speeds and power generation at higher speeds, which can lead to suboptimal fuel economy and engine performance.
Innovation Solution
Incorporating a variable-pitch stator with blades controllable by an actuator, and a bypass clutch with a separate hydraulic passage system, allowing for independent control of the stator pitch and clutch engagement pressure to adjust the torque converter's tightness, enabling dynamic adjustment of the K-factor based on operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-pitch stator is used in the torque converter, then the structure is simpler and manufacturing is easier, but the torque converter cannot dynamically adjust its K-factor to optimize performance across different operating conditions
Solution Approach 1:
The stator blades are made variable-pitch instead of fixed, allowing the stator to dynamically adjust its angle of attack based on operating conditions. This enables the torque converter to optimize its K-factor across different speed ratios and loading conditions, resolving the contradiction between adaptability and complexity by introducing controlled variability only where needed.
Solution Approach 2:
The stator blade pitch angle is changed as a controllable parameter rather than being fixed. By varying the pitch angle according to operating conditions, the torque converter can dynamically adjust its torque multiplication characteristics and K-factor, achieving adaptability without requiring a completely different design approach.
2Ease of operation
If a single hydraulic passage is used for both bypass clutch and stator actuation, then the device complexity is reduced, but the control precision and independent adjustment capability are compromised
Solution Approach 1:
The hydraulic control system is segmented into separate passages: one for bypass clutch actuation and another for stator actuator control. This segmentation allows independent control of each component, enabling precise adjustment of the stator pitch angle and bypass clutch engagement separately, which is essential for optimizing torque converter performance across different operating modes.
Solution Approach 2:
A dedicated hydraulic passage acts as an intermediary between the control system and the stator actuator, providing independent fluid pressure control for stator blade adjustment. This intermediary pathway enables decoupled control of the stator from the bypass clutch, achieving ease of operation despite increased hydraulic system complexity.
3Power
If the torque converter is designed to be tight for better power delivery, then power delivery is enhanced, but fuel economy deteriorates at lower speeds
Solution Approach 1:
The torque converter transitions from a static, fixed-tightness design to a dynamic system where the stator pitch angle can be adjusted in real-time. This allows the converter to optimize its tightness characteristic based on operating conditions, achieving both power delivery when needed and fuel economy during normal operation by dynamically adapting the stator angle.
Solution Approach 2:
The K-factor and tightness parameter of the torque converter are changed dynamically through stator blade angle adjustment rather than being fixed by design. By varying the stator pitch parameter, the system can shift between power-optimized and efficiency-optimized states, resolving the contradiction between power delivery and fuel economy.
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 allows for real-time optimization of the torque converter's tightness, improving fuel economy, reducing engine vibrations, and enhancing power delivery by adjusting the K-factor to suit specific driving conditions, such as starting from a standstill or high-power demands, while maintaining compatibility with existing transmission systems.
Implementation Method 1
A first hydraulic passage is in fluid communication with the apply chamber and the tightening chamber. The actuator is configured to tighten the blades in response to a first pressure being applied to the first hydraulic passage.
Implementation Method 2
The bypass clutch may include one or more clutch plates that rotate with the case and are interleaved with one or more disks that rotate with the input shaft. To engage the clutch, pressurized fluid forces a piston to compress the plates and disks.
Implementation Method 3
The stator redirects fluid returning from the turbine so that the fluid is rotating in the same direction as the impeller.
Data Source
AI summary
A torque converter includes a turbine disposed in a hydrodynamic chamber. A bypass clutch has an apply chamber fluidly isolated from the hydrodynamic chamber. A first hydraulic passage is in fluid communication with the apply chamber. A variable-pitch stator including blades controllable by an actuator that has a chamber in fluid communication with the first hydraulic passage.