Patents by Inventor Balarama V. Murty
Balarama V. Murty has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7571040Abstract: A method of controlling a magneto-rheological power steering coupling is provided. The method is to be employed by a controller and is initiated upon engine start-up. The method includes initializing calibration parameters and reading a plurality of input values. Subsequently, a hand wheel angle rate value is calculated from one of said plurality of input values. A pump speed command value is calculated as a function of at least the hand wheel angle rate value. A pump speed error value is then calculated, and a proportional-integral-derivative calculation is performed acting on the pump speed error value to determine a pulse width modulation duty cycle value. The duty cycle value is then output to a power driver to provide a control signal to the magneto-rheological power steering coupling. Also provided is control system and apparatus operable to perform the functions described hereinabove.Type: GrantFiled: February 10, 2006Date of Patent: August 4, 2009Assignee: GM Global Technology Operations, Inc.Inventors: Balarama V. Murty, Chandra S. Namuduri, Kenneth J. Shoemaker
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Patent number: 7422093Abstract: A magneto-rheological coupling (MRC) having an input assembly and an output member. The output member includes a generally cylindrical drum portion and a hub portion extending radially inwardly therefrom. The generally cylindrical drum portion has a low magnetically permeable region having a plurality of passages defined therein. Additionally, a plurality of apertures are defined by the hub portion. The plurality of passages and apertures enhance the flow of magneto-rheological fluid (MRF) within the MRC. The drum portion has a surface treatment of tungsten-carbide to enhance wear resistance. Additionally, the drum portion has an average roughness, or Ra value, of between 10 and 250 microns.Type: GrantFiled: January 27, 2006Date of Patent: September 9, 2008Assignee: GM Global Technology Operations, Inc.Inventors: Balarama V. Murty, Chandra S. Namuduri, Kenneth J. Shoemaker
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Patent number: 7334670Abstract: A magnetorheological (MR) fluid coupling for vectoring torque with respect to a shaft capable of rotary motion is disclosed. The coupling includes a stator, a rotor having a rotational degree of freedom with respect to the stator and configured for physical communication with the shaft, and a magnetic field generator. The stator and rotor define an annular space therebetween and are coupled via a MR fluid disposed within the annular space. The magnetic field generator is in field communication with the MR fluid and is disposed to produce a substantially radially directed magnetic field across the annular space. The rotor is rotationally responsive to the application of a magnetic field at the MR fluid.Type: GrantFiled: April 22, 2005Date of Patent: February 26, 2008Assignee: GM Global Technology Operations, Inc.Inventors: Chandra S. Namuduri, Balarama V. Murty, Anthony L. Smith, Jie Tong, Mark A. Golden, John C. Ulicny
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Patent number: 7296543Abstract: An engine coolant pump drive system for a vehicle having an engine, an engine coolant system, and at least one sensor for sensing at least one operational condition of the vehicle is disclosed. The pump drive system includes a magnetorheological fluid (MRF) clutch, and a coolant pump. The MRF clutch includes a torque input section coupled to a torque output section via a MRF, the torque input section being configured to receive a torque input from the engine. The coolant pump is configured for operable communication with the torque output section of the MRF clutch. In response to a signal from the at least one sensor, the MRF clutch is configured to provide a continuously variable torque transfer from the torque input section to the torque output section, thereby providing for variable coolant flow in the engine coolant system via the coolant pump capable of a continuously variable speed.Type: GrantFiled: April 6, 2006Date of Patent: November 20, 2007Assignee: GM Global Technology Operations, Inc.Inventors: Chandra S. Namuduri, David S. Rule, Balarama V. Murty
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Patent number: 7240485Abstract: A power steering system for a vehicle includes a hydraulic pump connected to a power steering gear of the vehicle and a fluid coupling interconnecting a drive shaft of an engine of the vehicle with the hydraulic pump. The power steering system also includes an electronic controller operable to provide a variable control signal based on received input and an amplifier to receive the variable control signal and energize the fluid coupling in response thereto to vary torque transmitted via the fluid coupling.Type: GrantFiled: April 1, 2005Date of Patent: July 10, 2007Assignee: GM Global Technology Operations, Inc.Inventors: Chandra S. Namuduri, Balarama V. Murty, Jie Tong
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Patent number: 7135784Abstract: A belted-alternator starter system that continuously provides pre-flux when the vehicle ignition is on and the engine is off to provide a faster torque response when the engine is turned on. The alternator/starter device operates as an alternator for providing electrical energy to vehicle electrical devices and the battery when the ignition is on and the engine is running, and operates as a starter for providing engine torque to start the engine when the engine is off and the ignition is on. The system further includes an inverter/rectifier circuit to provide AC current to the armature coils when the alternator/starter device is operating as a starter. The system provides an operating field current to the field coil when the ignition and the engine are on and provides a pre-flux field current to the field coil when the vehicle ignition is on and the engine is off.Type: GrantFiled: July 26, 2004Date of Patent: November 14, 2006Assignee: General Motors CorporationInventors: Balarama V. Murty, Chandra S. Namuduri
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Patent number: 5598814Abstract: A motor control includes position transducers for generating crankshaft position and motor position pulse trains. The pulse trains are compared to detect any phase difference between engine and motor. Tables are generated to define the desired phase difference needed for particular valve characteristics. The phase difference represents the instantaneous deviation from the basic profile. One of the tables is selected according to the engine conditions and the motor is driven to achieve the desired phase differences.Type: GrantFiled: December 15, 1994Date of Patent: February 4, 1997Assignee: General Motors CorporationInventors: Thaddeus Schroeder, Rassem R. Henry, Bruno P. B. Lequesne, Balarama V. Murty
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Patent number: 5475596Abstract: A method of control for a vehicle suspension system comprising four quarter car suspensions and a suspended vehicle body, comprising the steps of developing a quarter car command for each quarter car suspension in response to a signal representative of that quarter car state, developing a semi-rigid body command in response to a signal representative of a state of the suspended vehicle body, and developing a force command controlling force between sprung and unsprung masses in each quarter car suspension, the force command equal to the greater of the quarter car command and the semi-rigid body command.Type: GrantFiled: May 20, 1991Date of Patent: December 12, 1995Assignee: General Motors CorporationInventors: Rassem R. Henry, Michael A. Applebee, Balarama V. Murty
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Patent number: 5327856Abstract: Each valve of an internal combustion engine is driven by a separate rotary electric motor. A cam mechanism for the valves comprises a cylindrical cam in line with the motor axis and the valve stem, the mechanism having inner and outer cylinders, one cylinder rotating with the motor and carrying a cam and the other containing a cam follower and reciprocating with the valve.Type: GrantFiled: December 22, 1992Date of Patent: July 12, 1994Assignee: General Motors CorporationInventors: Thaddeus Schroeder, Rassem R. Henry, Bruno P. B. Lequesne, Balarama V. Murty
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Patent number: 5291106Abstract: A control system for an electric machine powered from a DC source, wherein controlled motoring and controlled braking are achieved with a single current regulator control, even when the DC source cannot accept charging current and/or the induced motor voltage exceeds the DC bus voltage. The motor control circuit comprises a DC source connected to a DC bus, a current control circuit for modulating switching devices connected across the DC bus, an energy exchange capacitor connected across the DC bus, a load resistor, a switching circuit effective when activated to interrupt a connection between the DC source and the DC bus and to connect the load resistor across the DC bus in parallel with the capacitor, and a logic circuit for activating the switching circuit during motor braking under conditions for which the modulation of the switching devices is ineffective to control the braking current.Type: GrantFiled: November 23, 1992Date of Patent: March 1, 1994Assignee: General Motors CorporationInventors: Balarama V. Murty, Chandra S. Namuduri
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Patent number: 5276621Abstract: A controller for a quarter car variable force suspension system responds to a signal representative of the system state. In response to the system state signal, the controller provides an actuator force control signal commanding (i) low level damping force when a magnitude value of the system state signal is below a magnitude of a dead zone limit, (ii) maximum available actuator force when the magnitude of the system state signal is above a magnitude of a boundary layer limit and (iii) actuator force proportional to the magnitude of the system state signal when the magnitude of the system state signal is above the magnitude of the dead zone limit and below the magnitude of the boundary layer limit, whereby the suspension system does not chatter and is not affected by system state signal error.Type: GrantFiled: May 20, 1991Date of Patent: January 4, 1994Assignee: General Motors CorporationInventors: Rassem R. Henry, Balarama V. Murty
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Patent number: 5091679Abstract: A vehicle suspension uses actuators between sprung and unsprung masses, each actuator comprising a brushless dynamoelectric machine having a low inertia rotor engaged with a rotary/linear motion converter or conversion between dynamoelectric machine torque and linear actuator force. A control circuit for each machine applies current from an electric power source to the dynamoelectric machine in response to rotor position sensors and an input control signal to produce a desired actuator force providing motoring or generating action by the dynamoelectric machine. A common supply bus connecting the electric power source and dynamoelectric machines allows the dynamoelectric machines in generating mode to provide electric power to the dynamoelectric machines in motoring mode. Transient storage capacitors across the supply bus, current limiting from the supply bus to the storage battery, a dump resistance and dump switch responsive to battery voltage, and a supplementary alternator are also provided.Type: GrantFiled: June 18, 1991Date of Patent: February 25, 1992Assignee: General Motors CorporationInventors: Balarama V. Murty, Rassem R. Henry
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Patent number: 4815575Abstract: An electric, variable damping suspension for a motor vehicle comprises a three phase rotary electric alternator, a ball screw and nut apparatus connecting the sprung and unsprung masses and driving the alternator in alternating rotary directions as the sprung and unsprung masses oscillate relative to each other, a rectifier bridge for converting the three phase alternator output to a single DC current, an electric load, and a switch for controlling the application of the DC current to the electrical load. Circuits determine the times of consecutive zero crossings of each phase and update therefrom a signal indicative of the magnitude of rattle space velocity. The circuits further determine, from the identities of the alternator phases of successive zero crossings of any phase compared with stored expected consecutive phase identities, the direction of the rattle space velocity.Type: GrantFiled: April 4, 1988Date of Patent: March 28, 1989Assignee: General Motors CorporationInventor: Balarama V. Murty
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Patent number: 4724710Abstract: An electromagnetic sensor for measuring the twist of a rotary shaft in response to the transmission of torque therethrough. Rotary magnetic sleeve means coupled to longitudinally displaced points on the shaft rotate relative to each other in proportion to the shaft deformation. Permanent magnets provide a source of magnetic flux, and a magnetic flux path is defined by a combination of the rotary sleeve means and a segmented stationary sleeve means. Relative rotation of the rotary sleeve means with deformation of the shaft progressively alters the density of the magnetic flux in the segmented stationary sleeve means, and a magnetic flux transducer positioned in an air gap between the stationary sleeve means segments detects the flux density therein to provide an indication of the amount of torque transmitted through the shaft.Type: GrantFiled: December 22, 1986Date of Patent: February 16, 1988Assignee: General Motors CorporationInventor: Balarama V. Murty
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Patent number: 4694135Abstract: A method and apparatus are disclosed for analyzing the dynamic resistance of a resistance spot welding process to determine the time of an expulsion event and use that time as the weld completion time for controlling weld termination via a weld feedback signal, controlling automatic current stepping, and identifying maintenance needs. A preconditioning pulse is used to stabilize the weld process and aid in obtaining interpretable resistance information. After an initial blanking period the resistance curve is analyzed by calculating first and second derivative values and applying several algorithms that make possible the computer recognition of characteristic resistance curve shapes resulting from weld expulsion under good geometry, bad geometry and edge weld conditions.Type: GrantFiled: July 9, 1986Date of Patent: September 15, 1987Assignee: General Motors CorporationInventors: Gregory L. Nagel, David M. Sidlosky, Balarama V. Murty, Anthony Lee, Dixon Cleveland