Driven Accessory Solenoid Clutch Variable Speed
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Solution Overview
Problem
Existing vehicle accessories such as coolant pumps and cooling fans consume excessive power, leading to reduced fuel economy and increased emissions, as they operate at a fixed rotational speed tied to the engine's crankshaft.
Innovation Solution
A driven accessory featuring a solenoid-actuated friction clutch system that allows the output member to operate independently of the input member, enabling selective engagement and disengagement based on cooling demand, reducing power consumption by disconnecting when not needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If accessories are directly driven by the crankshaft, then they operate reliably at fixed rotational speed, but power consumption increases and fuel economy deteriorates
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed direct-drive connection with a variable-speed belt drive system. The belt tension can be dynamically adjusted to maintain reliable accessory operation while allowing speed variation to reduce power consumption when full crankshaft speed is not required. This enables the system to transition from a static direct-drive configuration to a dynamic belt-driven configuration that can adapt operating conditions.
Solution Approach 2:
The patent applies parameter changes by modifying the rotational speed parameter of the accessories. Instead of maintaining a fixed 1:1 speed ratio with the crankshaft, the belt drive system allows the accessory speed to be varied independently. This parameter change enables the accessories to operate at lower speeds when cooling demand is reduced, thereby decreasing power consumption and improving fuel economy while maintaining adequate performance when needed.
2Reliability
If accessories operate at fixed rotational speed tied to crankshaft, then they provide consistent cooling, but fuel economy and emissions performance worsen
Solution Approach 1:
The variable-speed belt drive system enables dynamic adjustment of accessory rotational speed based on actual cooling demand. When the engine operates at temperatures within the optimal range, the belt can be slackened or the accessory speed reduced, allowing the system to transition from continuous full-speed operation to demand-based variable-speed operation. This maintains adequate cooling consistency while significantly reducing energy losses and improving fuel economy.
Solution Approach 2:
The patent implements periodic action by allowing the belt tension and accessory speed to be periodically adjusted according to engine operating conditions and cooling demand. Rather than maintaining constant high-speed operation, the system can cycle between higher speed modes (when cooling is needed) and lower speed or disengaged modes (when cooling demand is low), thereby reducing average power consumption and improving overall fuel economy while maintaining adequate cooling performance.
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 reduces power consumption and emissions by allowing accessories to operate only when required, thereby improving fuel economy and ensuring a reduced load on the engine.
Implementation Method 1
The clutch actuator has an electromagnetic coil that is disposed outside the clutch cavity
Data Source
AI summary
A driven accessory that includes an input member, a cover, an output member, a clutch and a clutch actuator. The input member is rotatable about an axis and has a hub, an outer rim, and a radially extending web that couples the hub to the outer rim. The cover is coupled to the input member for common rotation about the axis and cooperates with the input member to define a clutch cavity. The clutch is received in the clutch cavity and selectively transmits rotary power between the input member and the output member. The clutch actuator is selectively operable to change the operational state in which the clutch operates. The clutch actuator has an electromagnetic coil that is disposed outside the clutch cavity. The hub is disposed along the axis between the clutch and the electromagnetic coil.