Abstract: The present invention is particularly well suited for purifying exhaust from relatively large lean burn diesel engines. The emissions purification system causes an after-injection of fuel through the engine fuel injector during the exhaust stroke of an internal combustion engine. A computer controls the injector to inject an optimal amount of NOx reducing fuel into the engine cylinder. The optimal amount corresponds to an amount that will achieve optimal NOx reduction rates for the given engine operating condition and exhaust temperature. A computer periodically senses the engine operating condition and determines the exhaust temperature, and calculates the appropriate injection amount. With appropriate deNOx and oxidation catalysts located downstream from the injector, the emissions purification system of the present invention has the ability to greatly reduce NOx content of the exhaust while maintaining HC emissions at acceptable levels and greatly reducing system complexity.

Abstract: A precision demand axial piston pump with at least one spring for reducing cavitation. The pump includes a drive shaft driven to rotate about a drive axis of rotation. A cylinder block is connected disposed within a casing and is to rotate with the drive shaft and defines a plurality of cylindrical bores arranged parallel to a block axis of rotation. A fixed angle swash plate is positioned adjacent the cylinder block. A valve plate is mounted adjacent the cylinder block and defines an inlet passage and an outlet passage for fluid communication. A plurality of pistons, each having a shoe end, connected to a shoe, and a pressure face end, are slidably received in one of the cylindrical bores. The fixed angle swash plate provides the method for reciprocating the pistons with each revolution of the cylinder block. A throttle valve is positioned to control flow volume through the inlet passage and the pump.

Abstract: A hydraulically actuated fuel injection system includes a plurality of hydraulically actuated fuel injectors mounted into an actuation fluid rail. The injector and rail combination are mounted to an engine. The rail is connected to a source of relatively high pressure actuation fluid. The injectors are in fluid communication with the rail by an inner cavity in the rail and an actuation fluid inlet in the injector. The rail is a piece of metallic tubing with a plurality of bores therethrough for insertion of the injectors. The injectors are sealed from leakage of actuation fluid between the bores and the injectors with a pair of O-rings. A source of relatively low pressure fuel is provided separate from the actuation fluid rail to supply fuel to the injector through a fuel supply inlet. A bracket is used to fasten the injectors to the rail with a fastener. The same fastener may be used to mount the rail to the engine.

Abstract: In a hydraulically actuated fuel injector, each injection event is initiated and terminated by opening an actuation fluid cavity within the injector to a high pressure inlet source and a low pressure drain, respectively. The present invention is intended to provide a more abrupt ending to each injection event in order to improve performance and exhaust emission quality. The present invention incorporates a hydraulically actuated spill valve into the injector body. The spill valve exploits the pressure differential existing between the fuel pressurization chamber of the injector toward the end of each injection and the drop in pressure in the actuation fluid cavity. This pressure differential is exploited to hydraulically open a spill port to allow the residual fuel pressure to dissipate into a fuel return passage rather than dribble out of the injector nozzle while the needle check is moving toward its closed position.

Abstract: A structure and method for electronically minimizing or eliminating performance variation of an apparatus controllable by a control signal, such as an electronically-controlled fuel injector, is disclosed. The method includes the steps of measuring the resultant characteristics of the apparatus at a plurality of operating conditions, such as timing and delivery characteristics of the fuel injector, adjusting the control signal as a function of the measured resultant characteristics, such as by adjusting a base timing and duration or pulse width of a fuel delivery command signal for a fuel injector, and controlling the apparatus in accordance with the adjusted control signal to reduce performance variation.

Abstract: An apparatus and method for detecting the viscosity of actuating fluid used to actuate a hydraulically-actuated electronically-controlled injector is disclosed. In an internal combustion engine system including an engine having a crankshaft, a crankshaft angular speed sensor responsive to rotation of the crankshaft, a voltage sensor, and an engine coolant temperature sensor, which respectively generate angular speed, voltage, and temperature indicative signals, are provided. An electronic control module is provided with a memory means, the control module having an associated viscosity indicative signal or parameter whose magnitude is representative of the actuating fluid viscosity and is a function of the angular speed, and voltage indicative signals.

Abstract: A hydraulically-actuated fuel injection system is disclosed comprising an actuating fluid sump, a high pressure actuating fluid pump having a pumping chamber arranged in fluid communication with the sump, and a priming reservoir arranged in fluid communication between the sump and the inlet of the pump. Engines equipped with a hydraulically-actuated fuel injection system must be able to quickly pressurize actuating fluid in order to quickly start an engine. The priming reservoir is provided in order to prime and thereby facilitate rapid pressurization of the high pressure pump during startup of an engine.

Abstract: A hydraulically-actuated electronically-controlled unit injector fuel system and method of operation is disclosed. The fuel system comprises at least one hydraulically-actuated electronically-controlled unit injector and apparatus for supplying hydraulically actuating fluid to the inejctor. The fuel system also includes apparatus for detecting the pressure of the hydraulically actuating fluid supplied to the injector and for generating a presure indicative signal indicative of the pressure detected. The fuel system further includes apparatus for controlling the pressure of the hydraulically actuating fluid supplied to the injector and for correcting the pressure amount based on the pressure indicative signal. The present invention provides closed-loop control of actuating fluid pressure which helps ensure that a desired variable pressure setting is achieved and maintained for as long as needed.

Abstract: A structure and method for electronically minimizing or eliminating performance variation of an apparatus controllable by a control signal, such as an electronically-controlled fuel injector, is disclosed. The method includes the steps of measuring the resultant characteristics of the apparatus at a plurality of operating conditions, such as timing and delivery characteristics of the fuel injector, adjusting the control signal as a function of the measured resultant characteristics, such as by adjusting a base timing and duration or pulse width of a fuel delivery command signal for a fuel injector, and controlling the apparatus in accordance with the adjusted control signal to reduce performance variation.