Cummins Engine Company, Inc.

Kabushiki Kaisha Komatsu Seisakusho

Edward D Smith

Lester L Peters

Julius P Perr

David L Buchanan

Benjamin M Yen

Amarjit S Ghuman

George L Muntean

Yul J Tarr

Laszlo D Tikk

Gary L Gant

Harry L Wilson

Norman C Blizard

Hideo Furukawa

Edward J Lyford-Pike

Thomas A Oldfield

Raymond J Amlung

Chung Y Liu

Dan K Vetters

James A Wade

Mark Pounder

Andrew G Stiles

Michael D Breeden

James A Sting

Vinod K Duggal

Fuel injection rate shaping is integrated into the pressure intensification stage of a hydraulically actuated fuel injector having a pressure intensifier. In a first embodiment, the pressure intensification plunger is formed of two parts creating a damping chamber therebetween from which fluid is forced out through orifices in a lower one of the plunger parts during an initial phase of displacement of the upper part. Thus, injection will be performed initially at a lower pressure and rate, which increases once the plunger parts make contact. In a second embodiment, a throttled flow is set via a restrictor housing that telescopingly receives the upper plunger part, so that a lower injection rate occurs while fluid is bled off through a restricted flow path between the restrictor housing and the upper plunger part, and a higher injection rate is produced once a port in the upper plunger clears the restrictor housing. In a third embodiment, the two plunger parts of the intensifier have different areas relative to each other. In a fourth embodiment, flow to the intensifier plunger is varied by the intensifier plunger co-acting with a shaped inlet port increasing the effective area of the inlet port through which flow enters the intensifier as the intensifier plunger is displaced during its injection stroke. In a fifth embodiment, a throttling effect produced by a clearance between a protrusion on the intensifier plunger and a receiving bore in the intensifier body is used reduce the intensification effect during the initial phase of injection.

Hydraulically actuated fuel injector with injection rate shaping

A leak prevention device including an expandable chamber and control valve for preventing fuel leakage into the combustion chambers of a internal combustion engine equipped with a common rail fule injection system including open nozzle injectors and a shut off valve mounted in the common rail upstream of the fuel injectors to isolate, when closed, the fuel injectors from the source of fuel under pressure. The expandable chamber contains a variable volume held in its collapsed condition during engine operation and expanded upon engine shutdown sufficiently to prevent the flow of fuel from any injector into the corresponding combustion chamber. The control valve may be a three way valve for controlling the expansion of the variable volume of the expandable chamber The leak prevention device includes a housing assembly connected with a fuel drain and contains an outlet passage fluidically connected at one end with the variable volume and at the other end with the fuel drain and an outlet check valve for allowing fuel to flow in only one direction from the variable volume into the fuel drain. A control circuit is provided to energize solenoids for operating the shut off valve and control valve.

Variable volume chamber device for preventing leakage in an open nozzle

In accordance with preferred embodiments of the invention a timing adjustment device includes a cam follower that is engaged between an overhead cam and an injector rocker arm, and is mounted on a rotatable eccentric shaft. The geometry of the eccentric shaft and cam follower is designed so that, as timing is varied by rotation of the eccentric shaft, no change is produced in the vertical height of the rocker arm when the cam shaft is on the outer base circle and the injector is bottomed, in order to assure that the 'mechanical crush' of the PT type injector is constant despite changes in timing. In a first application of the timing arrangement, it is used together with a simple injector, which does not utilize a multi-plunger arrangement to form a hydraulic link, to achieve lower parasitic losses. To obtain independent control over injection pressure and timing, a fuel injector in which a hydraulic link is formed between plungers of a multi-plunger arrangement is used with the timing arrangement in order to allow the injection pressure to be maintained constant over a wide range of engine speeds without interfering with engine timing.

Variable injection timing and injection pressure control arrangement

A fuel system for fuel injectors of an internal combustion engine is provided with a hydromechanical timing valve having a valve body assembly with a barrel and plunger arrangement. The plunger is displaceable within the barrel under the counterbalancing forces of rail fuel pressure (load) and one or more timing valve springs. The relative position of the barrel and plunger determines the effective size of the port through which timing fluid can flow. In accordance a first embodiment, the plunger has a tapered head which covers and uncovers ports in the barrel to a greater or lesser extent, thereby creating a variable flow-through cross section. Alternatively, in accordance with other embodiments, the barrel has ports with slot-like orifices of progressively changing widths which coact with a metering groove on the spool to define a variable flow cross section through which the timing fluid must pass. Optionally, for highway motor vehicle applications, to increase fuel economy, a delayed timing advance feature can be incorporated into the timing valve. More specifically, by a controlled leakage effect, the valve plunger can be caused to shift in a direction causing timing to be advanced (timing fluid supply increased) only after a predetermined period of time has elapsed. This delayed timing advance can be produced, in accordance with the invention, via a second, internal plunger, or via a second, diaphragm-operated external plunger.

Infinitely variable hydromechanical timing control

An electro-hydraulic position-servo device to quickly and accurately position a stop element is provided for use with a positive displacement fuel injection system, wherein a shuttle is used to positively displace pre-metered slugs of fuel to unit injectors. The stop device is operatively associated with a control shaft having at least one helical surface thereon; the stop element and control shaft slidably located within a housing. The housing permits communication between at least one pressurized fluid source and a drain line by way of a chamber within which the control shaft is located. Thus, by simply rotating the control shaft from rotational drive means, the control shaft will assume an axial position determined by the orientation of the helical surface with respect to the supply and drain lines. The device is adjustable by rotation of the shaft to a new position with the re-orientation of the helical surface.

Position-servo device for positioning a stop in a positive displacement

An electronically controlled fuel supply system is provided for employing a plurality of fuel injectors which maximize SAC pressures under both low speed and high speed operating conditions and are capable of sustaining SAC pressures in excess of 30,000 psi. The fuel supply system of the present invention includes a gear pump which supplies pressure-modulated fuel to a fueling channel and to a timing channel and from there to a plurality of injectors. Fuel pressure regulator means and timing fluid pressure regulator means are provided in the fueling and timing channel, respectively. An electronic control unit receives information relating to engine operating conditions from a plurality of sensors and actuates the fuel pressure regulator means and the timing fluid pressure regulator means to adjust the pressure as required for the specific engine operating conditions. The timing fluid is delivered to the injectors by the present system at a pressure sufficient to sustain a hydraulic link within the injector of the length necessary to maintain high SAC pressures during injection. Several embodiments of a fuel supply system which achieves these objectives are disclosed. A mounting integral with the cylinder head for an electronically controlled injector fuel supply system is also provided.

Electronic controlled fuel supply system for high pressure injector

A hydromechanical fuel pump system of supplying timing fluid and fuel to high pressure fuel injectors utilizing a hydromechanical fuel control circuit to control the flow of fuel that is withdrawn from a fuel reservoir by a pump and delivered to the fuel injectors which includes a speed signal generator that produces a fuel pressure in a speed signal branch line of the fuel control circuit that is a function of engine rpm, and a torque shaping module that is provided in a fuel delivery branch of the fuel control circuit. The torque shaping module controls the supply pressure of the fuel flow to the injectors so that, during an initial engine operating range, the supply pressure is merely that as received from the fuel pump, in a second engine operating range, the torque shaping module causes the supply pressure to be a function of fuel pressure in the speed signal branch line as boosted by an assist means, the effect of which is removed in a third engine operating range, and in a last engine operating range, the supply pressure is determined by partially offsetting the effect of the pressure in the speed signal branch line by a counterpressure factor.

Hydromechanical fuel pump system

A system for effecting alternate fuel fumigation in an internal combustion engine including a fuel injector nozzle located in a scroll of a supercharger compressor associated with the engine. Schedules of secondary fuel addition as a function of engine load and as a function of engine speed are also disclosed as are fluid circuits used to effect such alternate fuel addition schedules.

Means and method for alternate fuel fumigation in internal combustion

A cam-operated, electronically controlled, unit fuel injector (2) including an injector body (4) containing a fluid timing circuit (20) and a fluid metering circuit (22) communicating with an injector cavity (14) within which is mounted a reciprocating plunger (16,76,78) operated by an injector cam (12) which causes the plunger (16,76,78) to experience first and second dwells during each injector cycle wherein fluid may flow in the timing circuit (20) but may not flow in the metering circuit (22) during the first dwell and may flow in the metering circuit (22) but may not flow in the timing circuit (20) during the second dwell and wherein a solenoid valve (44) is opened during the first dwell to control timing and is closed during the second dwell to control metering. Injector plunger (16) includes an inner plunger section (76) and an outer plunger section (78) mounted for independent reciprocal movement within the injector cavity (14) to define an injector chamber (80) adjacent the inner end of the injector cavity (14) and a variable volume timing chamber (90) between the inner and outer plunger sections. The timing chamber is filled with fuel during the first dwell to subsequent form a hydraulic link of variable effective length dependent upon the time of solenoid valve opening during the first dwell.

Solenoid operated unit injector having distinct timing, metering and

A fuel injection system is provided for a multicylinder internal combustion engine. Each cylinder is provided with at least one fuel injector. The system includes a cam-operated pumping plunger which maintains fluid pressure within an accumulator and controls the intermittent application of fluid pressure from the accumulator through a first chamber in which the plunger moves to one end of a metering plunger. The opposite end of the metering plunger coacts with a second chamber in which the metering plunger moves to define a cavity into which fuel is supplied for subsequent feeding to the cylinder injector. Fuel enters the cavity during those periods when the metering plunger is not subjected to the accumulator fluid pressure, the latter being under the control of the pumping plunger. The pumping plunger reciprocates within its chamber and is rotatable about its longitudinal axis. An elongated groove is formed in and encompasses the exterior of the pumping plunger. The effective axial length of the groove may be varied depending upon the relative position of rotation of the pumping plunger within the first chamber, so that the time may be changed as to when the accumulator fluid pressure is intermittently supplied to the metering plunger via the first chamber and during the pumping stroke of the plunger. The rotational adjustment of the pumping plunger is controlled by external means which may be responsive to the operational demands of the engine.

Fuel injection system

This disclosure relates to a turbocharged low compression ratio diesel engine. An air by-pass is connected in parallel with the engine and is operable to by-pass a portion of the compressor output around the engine and into the exhaust manifold. A control is connected in the by-pass to regulate the amount of by-passed air, the control operating in response to the compressor output. The by-pass further includes means for heating the air flowing to the turbine to aid fuel combustion in the engine cylinders.

Turbocharged internal combustion engine

The disclosure illustrates a fuel control valve for a fuel system of a compression ignition engine which utilizes unit fuel injectors operating on the principle that the fuel pressure applied to the injectors determines the quantity of fuel injected into the engine cylinders. The fuel control valve is connected in the supply line for half of the injectors of the engine. The valve has a plunger which blocks off flow to these injectors whenever the fuel system pressure is below a predetermined level. When the pressure exceeds that level, the plunger displaces to a position where it permits flow to the injectors and offers a minimum restriction to flow. The pressure level is set at a level which reflects engine operation above idle but below normal engine operating conditions. The net effect is to substantially reduce the generation of white smoke during engine startup and while idling for extended periods of time while not affecting normal engine operating conditions. The selective termination of fuel to a portion of the cylinders has a beneficial effect on other engine emissions.

Fuel system for internal combustion engine

The disclosure illustrates an anti-tampering fuel control valve for a fuel system providing fuel at a regulated pressure to a series of unit injectors on a diesel engine. The injectors are cam actuated to inject fuel quantities related to the pressure of the fuel supplied to them. The control valve bypasses fuel from the output of the fuel system to a low pressure region when the pressure exceeds a first given level because of fuel system tampering. Orifices in the bypass flow path cause the fuel pressure to follow a schedule generally similar to the normal system pressure schedule but at lower levels. Bypass flow is continued until the fuel system pressure drops to a lower pressure than the pressure at which bypass flow begins.

Fuel control valve

This disclosure deals with a variable fluid pressure regulator wherein the level at which the fluid pressure is regulated is adjustable. A member has a flow passage formed therein, and the fluid flows through the passage and out of the member, and a closure is positioned over the opening. The closure is yieldably mounted relative to the member and a spring urges the closure toward the opening. A recess or cavity is formed in the closure, and the fluid flows from the opening, into the recess, and then through a space between the closure and the member. The fluid pressure in the passage is a function of the spring force and the effective area of fluid pressure on the closure, and the effective area comprises the area of the opening plus any area of the recess which lies outside the margin of the opening. The regulated fluid pressure level may be varied by laterally shifting the closure relative to the opening in order to change the effective area.

Growing community of inventors

Greensburg, IN, United States of America

Edward D Smith