Clutched Vacuum Pump With Demand-Based Camshaft Engagement
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Solution Overview
Problem
Existing mechanical clutches for vacuum pumps in vehicles are inefficient and costly, with conventional electrical pumps experiencing energy losses and high costs, and existing mechanical clutches lack an elegant solution for demand-based operation.
Innovation Solution
A clutched vacuum pump assembly using a wrap spring clutch and vacuum actuator that connects or disconnects a camshaft to a rotor based on air pressure in a vacuum conduit, allowing for efficient operation only when vacuum is needed, with a torque limiting clutch to manage torque transfer and an oil flow control system to optimize energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum pump is continuously operated to ensure vacuum availability, then vacuum reliability is improved, but energy consumption increases
Solution Approach 1:
The vacuum pump system transitions from static continuous operation to dynamic demand-based operation through the clutch mechanism. The pump operates only when vacuum demand is detected via the vacuum sensor, adjusting its operational state dynamically to match actual needs, thereby reducing energy consumption while maintaining vacuum reliability.
Solution Approach 2:
The system implements feedback control through the vacuum sensor that continuously monitors vacuum levels and signals the control unit. When vacuum drops below a threshold, the sensor triggers the clutch to engage the pump; when vacuum is sufficient, it signals disengagement. This closed-loop feedback ensures reliable vacuum availability while minimizing unnecessary operation and energy waste.
2Use of energy by moving object
If electrical pumps are used to enable on-demand operation, then energy efficiency is improved, but system cost and energy conversion losses increase
Solution Approach 1:
The invention replaces electrical pump systems with a mechanical clutch-controlled mechanical pump system. Instead of using expensive electrical pumps that require electrical-mechanical energy conversion, the system uses a mechanically actuated clutch (electromagnetic or electro-hydraulic) to engage/disengage a conventional mechanical pump, eliminating conversion losses and reducing system cost while maintaining on-demand operation capability.
Solution Approach 2:
The clutch acts as an intermediary mechanism between the power source and the vacuum pump. Rather than directly controlling pump operation through electrical means, the clutch serves as a mechanical mediator that transmits or blocks power flow based on vacuum demand signals, enabling efficient on-demand operation with reduced complexity and cost.
3Use of energy by moving object
If a clutch mechanism is added to enable on-demand pump operation, then energy consumption is reduced, but device complexity increases
Solution Approach 1:
The clutch mechanism is integrated into the existing powertrain architecture, utilizing the engine's accessory belt system and power take-off points. The same clutch assembly serves multiple functions: enabling on-demand pump operation, providing torque limitation protection, and integrating with the engine's existing mechanical infrastructure. This multi-functionality reduces the net increase in system complexity while achieving energy savings.
Solution Approach 2:
The vacuum pump system with clutch control serves itself by automatically engaging and disengaging based on vacuum level feedback without requiring external intervention. The system monitors its own vacuum output through the sensor and autonomously controls the clutch actuator, making the complexity pay-off worthwhile through significant energy reduction and eliminated need for separate control systems.
4Reliability
If torque is limited to extend component lifespan, then reliability is improved, but power transmission capability is reduced
Solution Approach 1:
The torque limitation mechanism dynamically adjusts the torque transmission parameter based on operating conditions. During normal operation, the clutch transmits full torque; during startup or overload conditions, the torque limiter engages to restrict torque to safe levels. This parameter change protects components from damage while maintaining full power transmission capability during normal operation, extending component lifespan without permanently reducing power 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
The solution reduces energy consumption by only generating vacuum when needed, improves fuel efficiency, and extends component lifespan by managing torque and oil flow, resulting in a more efficient and cost-effective vacuum pump system.
Implementation Method 1
a wrap spring clutch and vacuum actuator that connects or disconnects a camshaft to a rotor
Implementation Method 2
The vacuum actuator is movable, based on air pressure in the vacuum conduit, between a low pressure position and a high pressure position
Data Source
AI summary
A system is provided for generating vacuum in a vehicle. The system includes a vacuum pump, an engagement clutch, an actuator, and a torque limiting clutch. The engagement clutch operatively connects a camshaft to the rotor. The actuator controls the clutch. The actuator is movable, based on air pressure in a vacuum conduit, between a low-pressure position in which the actuator causes the clutch to operatively disconnect the camshaft from the rotor, and a high-pressure position in which the actuator causes the clutch to operatively connect the camshaft to the rotor. The torque limiting clutch limits torque transfer to the rotor when the engagement clutch operatively connects the camshaft to the rotor. The system also provides control for hysteresis.