Browse Topic: Magnetic clutches

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Mechanically Supercharged 2.4L GDI Engine for Improved Fuel Economy and Low Speed Torque Improvement2014-01-11864/1/2014
This paper describes the simulation, design, and testing of a mechanically supercharged 2.4L I-4 gasoline direct injection engine with Miller cycle late intake valve closing and high geometric compression ratio. Engine downspeeding is also achieved through modified transmission gear ratios. A 3.3L naturally-aspirated V6 engine was chosen as the benchmark for comparison. Intended vehicle application is a mid-size passenger car or small/mid-size CUV. The CAE tool GT-Power was used for component selection and air path development. The powertrain simulation model was then exercised to show both improved fuel economy and performance compared to the V6 baseline engine. The design of a bespoke integrated supercharger with magnetic clutch, charge air cooler, and intake manifold was made and procured. A large new software aggregate was ported into an existing production ECU with modified internal circuitry. Volumetric efficiency was calibrated using automated engine mapping techniques and software. Data reduction methods compiled the raw outputs into a point-slope format. A full factorial design of experiments yielded models for the most potent calibration areas. Engine dynamometer results show promising fuel economy improvement under simulated FTP drive cycles. Development for supercharger clutch control and in-vehicle testing is currently in progress.
Birckett, Aaron, Engineer, Nayan, Arlauskas, Paul, Shirley, Mark, Neuman, Paul
Air Conditioning System Utilizing Vehicle Waste Energy2009-01-05434/20/2009
This paper describes conceptual design modifications that can be made to conventional, non-hybrid passenger vehicles, to allow the air conditioning refrigerant compressor to be powered by vehicle waste kinetic energy occurring during those times when the driver’s foot is off the gas. Without affecting passenger comfort, such compressor engagements, using regenerated waste energy, directly offsets engine fuel otherwise consumed for equivalent engine driven engagements. This results in significant fuel savings when the air conditioning system is operating during traffic pattern conditions. In conventional system operation, a magnetic clutch mounted on an engine-driven drive pulley is electrically controlled to engage the compressor and restore refrigerant pressure each time its state of pressurization bleeds down to a predetermined minimum set-point. Vehicle waste energy generation, however, which allows the engine to be rotated via existing vehicle momentum during deceleration (overrunning), rather than via engine fuel, is controlled by the position of the driver’s foot on the gas in accordance with the state of traffic. By coordinating compressor operation with those times when the driver’s foot is off the gas, vehicle waste energy can be utilized to power the compressor. In order to show the conceptual viability of identifying and harnessing vehicle waste energy to power the compressor, road test data was compiled on two test vehicles operating under simulated traffic pattern conditions. The air conditioning systems of the test vehicles were modified, via external test circuits, to automatically engage the refrigerant compressor magnetic clutch every time the driver’s foot stepped off the gas, and disengage when the driver stepped back on. Analysis of the test data showed a significant percentage reduction of engine-driven refrigerant re-pressurization cycles, these having been replaced with equivalent vehicle waste energy-powered re-pressurization cycles during engine overrunning conditions. Although not directly measured in this study, any reduction of engine driven compressor operation likely translates into a degree of savings of the extra fuel normally consumed during air conditioner operation, as most of the extra engine fuel consumed when operating the air conditioner comes from the additional engine load of operating the compressor. With such testing establishing the ability to identify and harness vehicle waste kinetic energy to power the compressor, two concepts are presented that could be adapted to the air conditioning systems of OEM vehicles to allow vehicle waste kinetic energy to seamlessly power a very significant portion of air conditioning compressor engagements during traffic pattern driving conditions.
Harrison, Thomas D.
High Efficiency Supercharger Increases Engine Output, Reduces Fuel Consumption Through Computer Control86139210/1/1986
Efficiency of a supercharger mainly depends on the clearances between the rotors and the housing, but it has hitherto proved impossible to reduce the clearances without a strong possibility of seizure. A two lobe Roots type supercharger has been developed which overcomes this problem by means of a special resin coating on the rotors. As a result, an increase of 18% in volumetric efficiency of the supercharger is achieved. Engine torque is increased by 30%. Drive power loss resulting from the operation of a supercharger at partial load when boost was not required caused fuel consumption to increase by about 10%. An electro magnetic clutch and an air by-pass valve controlled by the onboard computer were used in the new supercharger to eliminate this fuel economy loss. A passenger car equipped with the new supercharged 2-liter engine demonstrated about the same acceleration performance as a 3-liter class car without sacrificing fuel economy.
Kato, Shinichi, Nakamura, Norihiko, Kato, Kichiro, Ohnaka, Hidemi
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