Patents by Inventor Ulrich Letsche
Ulrich Letsche 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: 6601552Abstract: A hydraulically controllable globe valve having a stem piston to which pressure can be applied by a spring connected to a pressure source, with the stem piston being able to move from a first end position in the direction of a second end position. Pressure control means are provided which maintain a constant pressure of the hydraulic spring means on the stem piston while the latter moves from the first end position in the direction of the second end position by connecting the hydraulic spring means to a pressure source during a variable portion of the valve lift. The valve can be used, for example, as a gas exchange valve in a reciprocating engine.Type: GrantFiled: October 31, 2002Date of Patent: August 5, 2003Assignee: DaimlerChrysler AGInventors: Michael Kübel, Knud Lembke, Ulrich Letsche, Rudolf Thom
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Patent number: 6564758Abstract: A method for operating an internal combustion engine with variable gas exchange control times and with variable control times for the inlet and outlet valves includes, in various operating modes, direct exhaust-gas recirculation by the retarded closing of the outlet valve, exhaust-gas retention by the insertion of a compression and expansion phase with closed gas exchange valves, exhaust-gas filling of the combustion space by the opening of the outlet valve in the gas intake phase, with the inlet valve closed, and/or an apportionment of the combustion action, if appropriate combined with an exhaust emission control measure, to a plurality of working strokes of a working cycle. The various operating modes may be set individually for each combustion space and each working cycle. The method may by used, for example, for gasoline and diesel engines of motor vehicles.Type: GrantFiled: December 17, 2001Date of Patent: May 20, 2003Assignee: DaimlerChrysler AGInventors: Christian Enderle, Walter Friess, Jürgen Ganser, Ulrich Letsche
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Publication number: 20030047153Abstract: A hydraulically controllable globe valve having a stem piston to which pressure can be applied by a spring connected to a pressure source, with the stem piston being able to move from a first end position in the direction of a second end position. Pressure control means are provided which maintain a constant pressure of the hydraulic spring means on the stem piston while the latter moves from the first end position in the direction of the second end position by connecting the hydraulic spring means to a pressure source during a variable portion of the valve lift. The valve can be used, for example, as a gas exchange valve in a reciprocating engine.Type: ApplicationFiled: October 31, 2002Publication date: March 13, 2003Inventors: Michael Kubel, Knud Lembke, Ulrich Letsche, Rudolf Thom
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Patent number: 6491007Abstract: A hydraulically controllable globe valve having a stem piston to which pressure can be applied by a spring connected to a pressure source, with the stem piston being able to move from a first end position in the direction of a second end position. Pressure control means are provided which maintain a constant pressure of the hydraulic spring means on the stem piston while the latter moves from the first end position in the direction of the second end position by connecting the hydraulic spring means to a pressure source during a variable portion of the valve lift. The valve can be used, for example, as a gas exchange valve in a reciprocating engine.Type: GrantFiled: November 19, 1999Date of Patent: December 10, 2002Assignee: Daimler Chrysler AGInventors: Michael Kübel, Knud Lembke, Ulrich Letsche, Rudolf Thom
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Patent number: 6167853Abstract: The invention relates to a hydraulic control device for a lifting valve, the said device comprising a valve stem capable of being moved by two spring means acting in opposition to one another, the valve stem being capable of being activated hydraulically in the region of its end positions. According to the invention, the hydraulic control device contains a hydraulically regulatable spring means which is assigned a hydraulically acting auxiliary control member, by means of which the working fluid of the hydraulically regulatable spring means can be relieved of pressure.Type: GrantFiled: March 22, 2000Date of Patent: January 2, 2001Assignee: DaimlerChrysler AGInventor: Ulrich Letsche
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Patent number: 5943988Abstract: In an operating arrangement for a gas change valve of an internal combustion engine including an electromagnetic structure having an armature which is connected to the valve and which forms an operating piston disposed in a cylinder for reciprocating movement therein between an upper end position in which the valve is closed and a lower end position in which the valve is open, at least a first electromagnet is arranged adjacent the lower end position of the armature for retaining the armature when the electromagnet is energized, a spring is provided for biasing the valve to a closed position and electro-pneumatic means are provided for supplying gas under pressure to an operating chamber at one side of the piston for actuating the piston in a valve opening direction.Type: GrantFiled: June 12, 1998Date of Patent: August 31, 1999Assignee: Daimler Chrysler AGInventors: Dieter Burger, Ulrich Letsche, Jurgen Schule
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Patent number: 5809950Abstract: In a hydraulic valve control arrangement particularly of an internal combustion engine wherein the valve has a valve stem by which it is supported so as to be slideable between a closed and an open position and first there are provided first spring means biasing the valve in the closed position and second spring means providing an opening force which is transmitted via a valve tappet and an end of the valve tappet is received in a cylinder which is engaged by the second spring means so as to form a hydraulic force transmitting structure to which hydraulic fluid can be admitted for tensioning the second spring means. The valve tappet has a control piston received in a control chamber to which pressurized fluid is admitted which holds the control piston in either of its open or closed valve end positions and a pressure space is arranged adjacent the closed valve end positions of the control piston to which pressurized fluid can be admitted for initiating opening of the valve.Type: GrantFiled: May 30, 1997Date of Patent: September 22, 1998Assignee: Daimler-Benz AGInventors: Ulrich Letsche, Ralf Gapp
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Patent number: 5765515Abstract: In a hydraulic operating mechanism for a valve which comprises a valve stem with first spring means acting on the valve stem in the valve closing direction, and second spring means acting at least intermittently on the valve stem in a valve opening direction, the compressing force of the second spring means is controlled hydraulically during the operation of the valve control device. In order to keep the control forces required for operating the valve as low as possible over its entire operating range, the second spring means comprises a spring combination composed of at least two springs which have different spring forces providing for a maximum spring force of the second spring means at the start of the valve opening stroke.Type: GrantFiled: May 19, 1997Date of Patent: June 16, 1998Assignee: Daimler-Benz AGInventor: Ulrich Letsche
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Patent number: 5645030Abstract: In a motorbraking arrangement for a Diesel engine with at least one engine breathing valve and at least one fuel injector per cylinder and a high pressure fuel pump with a high pressure fuel reservoir for supplying high pressure fuel to the injectors, a control valve is provided for controlling the supply of fuel from the high pressure fuel reservoir to the breathing valve for its actuation during an engine compression stroke and a lower pressure fluid supply system is provided for operating the breathing valve during normal engine operation under the control of switch-over means which place the breathing valve in communication either with the high pressure fuel reservoir or with the lower pressure fluid supply system.Type: GrantFiled: July 15, 1996Date of Patent: July 8, 1997Assignee: Daimler-Bauz AGInventor: Ulrich Letsche
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Patent number: 5595148Abstract: The invention relates to a freely activatable hydraulic valve control device for a stroke valve, which valve control device is arranged particularly in an internal-combustion engine. The stroke valve includes a valve stem and a first spring acting on the valve stem in the valve-closing direction as well as a second spring acting at least periodically on the valve stem in the valve-opening direction. The valve stem is connected at least to a control piston arranged in a working space and capable of being loaded on two sides with a working fluid. The pressure of the working fluid in the working space can be regulated via a pressure source together with a switching valve and a supply conduit.Type: GrantFiled: January 19, 1996Date of Patent: January 21, 1997Assignee: Mercedes-Benz AGInventors: Ulrich Letsche, Andreas Rehberger, Frank Iberle
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Patent number: 4930464Abstract: A hydraulically operating actuating device for a lift valve, in particular in an internal combustion engine, has a piston which is connected to the valve stem. The piston is positioned in a cylinder and separates two stroke spaces which are connectable, in each case via inlet and outlet openings which can be occluded by the piston, to a pump for the working fluid or a reservoir. In order to reduce the energy requirement of the actuating device, the two inlet openings, which in a central actuation range of the piston are open, are connected to one another directly by a line, and two springs which act in opposite directions and, in equilibrium, hold the piston in a central position relative to two end positions engage on the piston or valve stem.Type: GrantFiled: September 27, 1989Date of Patent: June 5, 1990Assignee: Daimler-Benz AGInventor: Ulrich Letsche
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Patent number: 4903896Abstract: The invention relates to a fuel injection device for an air-compressing fuel-injected internal combustion engine, which has an injection line leading from a pump element of high pressure injection pump to a bifurcation branch leading to a main injection nozzle and a preinjection nozzle. A nozzle needle of the preinjection nozzle opens counter to the direction of flow of the fuel and has a body designed with a stepped piston which, in the case of a closure initiating fuel pressure lying above an opening fuel pressure of the nozzle needle, moves the nozzle into a position to end preinjection.Type: GrantFiled: April 6, 1989Date of Patent: February 27, 1990Assignee: Daimler-Benz AGInventors: Ulrich Letsche, Gunther Hafner, Karl-Ernst Noreikat
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Patent number: 4763841Abstract: An injection nozzle for injecting fuel into the combustion chamber of an air-compressing internal combustion engine is provided, having a valve closing member which lifts inwards from its valve seat as a function of the fuel pressure. The valve closing member is formed by a diaphragm which is firmly clamped in the nozzle body and lifts to a greater extent during the opening pressure of the injected fuel in the direction of the spray openings. A dilatant liquid or a non-dilatant liquid with a certain portion of gas is used as a closing spring for the diaphragm.Type: GrantFiled: April 8, 1987Date of Patent: August 16, 1988Assignee: Daimler-Benz AktiengesellschaftInventors: Gunther Hafner, Ulrich Letsche
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Patent number: 4712530Abstract: This invention relates to a hydraulic adjustment arrangement for the control of the injection start for a motor vehicle internal combustion engine, consisting of a primary part on the side of the internal-combustion engine and a secondary part on the side of the injection pump as well as radial pistons operating as a function of the admission of hydraulic oil, said radial pistons operating as a function of the admission of hydraulic oil, said radial pistons being guided in cylinders contained in the secondary part and interacting with levers extending in a circumferential direction and being pivoted on the secondary side, flexible connectors resting on said levers in one portion and fixed to the primary part on another portion, such that a radial movement of the pistons and as corresponding outward swivel movement of the levers and the flexible connectors causes a rotation of the secondary part relative to the primary part.Type: GrantFiled: November 4, 1985Date of Patent: December 15, 1987Assignee: Daimler-Benz AktiengesellschaftInventors: Wolfgang Rapp, deceased, Gunther Hafner, Ulrich Letsche
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Patent number: 4711220Abstract: This invention relates to a hydraulic-oil feeding device for a hydraulically operated injection timing mechanism disposed on the injection pump shaft of an injection pump for air-compressing injection-type internal-combustion engines. A pump shaft is partially disposed in an injection pump housing. A feeding member leads from the pump housing to the pump shaft. An arrangement of bores forms a passage or transition between the feeding member and the injection timing mechanism. The passage is interrupted during each injection process, and the passage is open in between injection processes.Type: GrantFiled: November 4, 1985Date of Patent: December 8, 1987Assignee: Daimler-Benz AktiengesellschaftInventors: Ulrich Letsche, Wolfgang Rapp, deceased, Guenther Haefner, Wilhelm Tonhaeuser
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Patent number: 4655254Abstract: A control valve, in particular, an electrohydraulic control valve for controlling the injection pump of a diesel engine, incorporates a slider which is guided in a housing, in a manner permitting movement in the axial direction, the housing possessing radial flow-ports and, in the region of the inner peripheral surface, at least one annular space carrying a fluid. In order to ensure that the control-valve housing can be manufactured economically, the annular space is formed by a plurality of flow-ports which intersect in the region of the inner peripheral surface of the housing and pierce the housing radially.Type: GrantFiled: December 20, 1985Date of Patent: April 7, 1987Assignee: Daimler-Benz AktiengesellschaftInventors: Gunther Hafner, Karl-Ernst Noreikat, Hans-Dieter Schmidt, Ulrich Letsche, Bernhard Bauer
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Patent number: 4615321Abstract: A method and apparatus for checking sensors, in which the measurement signals, electrically detected in a checking unit and representative of the operating conditions of an internal combustion engine, are statically monitored. The measurement signals are checked with respect to whether their physical measured values are technically significant and lie within the permissible range and if an error is detected, a measure is initiated which counteracts this error; the cyclically detected measurement signals are thereby checked with respect to a change in their measured values from one sampling cycle to a successive one and are accepted only if the change in measured values is within permissible limits. Stochastic disturbances are gated out of the measurement signal and registered and tolerated up to a significant limit. If faulty measurement signals are detected, an emergency operating procedure is activated which counteracts this fault.Type: GrantFiled: August 6, 1984Date of Patent: October 7, 1986Assignee: Daimler-Benz AktiengesellschaftInventors: Gunther Haefner, Bernhard Bauer, Ulrich Letsche, Karl-Ernst Noreikat
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Patent number: 4546426Abstract: A method and an apparatus for controlling the position of an actuator contemplates generating a signal indicative of actuator position, generating a signal indicative of desired actuator position, comparing the actuator position signal to the desired actuator position signal, and generating an error signal from the comparison. The error signal is provided to a control unit, and an adaptation signal is generated in an adaptive system. A control signal is provided by the control unit, and is combined with the adaptation signal to provide an adapted control signal. The adapted control signal is provided to the actuator to control it.Type: GrantFiled: March 1, 1983Date of Patent: October 8, 1985Assignee: Daimler-Benz AktiengesellschaftInventors: Gunther Hafner, Karl-Ernst Noreikat, Hans-Dieter Schmidt, Ulrich Letsche, Bernhard Bauer
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Patent number: 4509488Abstract: A process for intermittent control of a cyclically operating internal combustion engine wherein, in the succession of working cycles, working strokes are skipped--in approximately uniform distribution--and the number of skips is varied in dependence on the load. Fuel is fed in a controlled fashion only to the nonskipping working chambers of the internal combustion engine independently of the load in a constant quantity optimal for consumption. For a sensitive power distribution, especially in the low load range, the number of skips is varied chronologically at least approximately randomly and independently of the speed, i.e., the temporal density of the working strokes is varied. This can be accomplished by setting differently finely staggered firing patterns or by a stochastic ignition setting.Type: GrantFiled: July 12, 1982Date of Patent: April 9, 1985Assignee: Daimler-Benz AktiengesellschaftInventors: Hans-Joachim Forster, Bernd-Eric Lubbing, Ulrich Letsche