Cummins Engine Company, Inc.

David A Olson

Paul D Free

Keith L Musser

Michael J Ruth

Stephen M Holl

Daniel D Wilhelm

Gregory A Weber

Tibor J Villanyi

Stephen West

David A Bolis

Shyamala Raghunathan

James Hugh Ross

Jonathan A Stavnheim

Jeffrey P Seger

Walter Wayne Eberhard

Prakash Bedapudi

B Doszpoly

Jerome M Long

John J McCosby

A fuel system includes an electronically controllable high pressure fuel pump operable to supply high pressure fuel from a lower pressure fuel source to a high pressure fuel collection chamber having a pressure sensor associated therewith. The fuel collection chamber feeds an electronically controllable valve operable to dispense the high pressure fuel to a fuel distribution unit supplying fuel to a number of fuel injectors. A control computer is provided for controlling the high pressure fuel pump and valve in response to requested fueling, engine speed and fuel pressure provided by the pressure sensor. The control computer is normally operable to drive the fuel pump as a function of fuel pressure and a reference pressure, which is based on requested fueling, and to control the valve as a function of commanded fueling, which is a function of engine speed and a reference speed based on requested fueling, and fuel pressure. In a first limp home mode, the control computer is operable to drive the fuel pump as a function of fuel pressure and commanded fueling if abnormal operation of the high pressure fuel pump is detected. In this mode, the valve is controlled only as a function of fuel pressure. In a second limp home mode, the control computer is operable to drive the fuel pump with a predicted fuel pump command based on the fuel command and engine speed, if abnormal operation of the pressure sensor is detected. In this mode, the valve is controlled as a function of the fuel command and the reference pressure or a default pressure.

Apparatus for controlling a fuel system of an internal combustion engine

A system for controlling fuel flow in an internal combustion engine receives a command specifying a desired fuel flow rate from an electronic control module. The system generates a feedforward estimate of actuator current required to produce the desired flow rate. This estimate is combined with a fueling current offset value generated using a proportional-integral feedback controller. A differential pressure between the fuel rail and cylinder gas is converted, by surface interpolation based on a lookup table, to an estimate of actual fuel flow rate. The difference between this actual fuel flow rate and the desired flow rate is provided to the feedback controller as an error signal. The feedback controller preferably uses different gain values depending on an operating mode of the engine (speed control and torque control modes).

Apparatus and method for accurately controlling fuel injection flow rate

A viscosity sensitive, pressure divider arrangement for use as part of an engine timing control tappet system where that system includes a block oil pressure supply, hydromechanical control valve and an oil sump, the pressure divider arrangement including an inlet chamber, a divider chamber and an exit chamber. The inlet chamber is connected to the divider chamber by means of a first connecting conduit having a relatively short length. The outlet side of the divider chamber is connected with the exit chamber by means of a second connecting conduit which has a length substantially longer than the length of the first connecting conduit. Additionally, the divider chamber includes a pressure-assist outlet aperture which is in flow communication with the hydromechanical control valve. The viscosity of oil flowing into the pressure divider arrangement will be acted upon by the combination of connecting conduits wherein the first connecting conduit is less viscosity sensitive than is the second connecting conduit. Consequently, a controlling pressure will be created within the divider chamber and this controlling (assist) pressure is communicated to the hydromechanical control valve and influences the switch point of that control valve.

Viscosity sensitive auxiliary circuit for hydromechanical control valve

A flow controlling system having a viscosity sensitive means for producing a simulated fluid pressure which varies in correspondence with a fluid pressure at a predetermined portion of a fluid flow circuit on the basis of the viscosity of the fluid flowing through the circuit, and a pressure regulating means, that is responsive to changes in the simulated pressure, for maintaining a predetermined pressure at that predetermined portion of the fluid flow circuit. In particular, in a preferred embodiment of the invention, the flow controlling system is utilized in an engine timing control tappet system of the type having at least one expansible tappet for controlling timing of a fuel injector using oil that is supplied by a pump to an engine lubrication circuit.

Viscosity responsive pressure regulator and timing control tappet system

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Columbus, IN, United States of America

David A Olson