Caterpillar Inc.

Chetan J Desai

Xinshuang Nan

Scott F Shafer

Ronald Dean Shinogle

Ye Tian

Lifeng Wang

David J Beatty

Jerry A Wear

George M Matta

Michael A Flinn

David L Fuelberth

Jianyuan Yang

Norval J Weimken

Xinshaung Nan

Engineers have determined that the ability to front end rate shape injection events can result in a number of advantages, including improved injector performance and a reduction in undesirable emissions. In addition, engineers have learned that it is desirable for the needle valve to open slowly at the beginning of an injection event and to close abruptly to end the injection event. Therefore, the present invention utilizes at least one orifice member that is movably positioned in an injector body such that fluid flowing away from the needle valve member closing hydraulic surface flows through a relatively restricted flow path and fluid flowing toward the needle valve member flow through a relatively unrestricted flow path.

Variable control orifice member and fuel injector using same

The present invention relates to common rail fuel injectors, and includes an example of such an injector, a fuel injection system employing such an injector, and a method of injecting fuel. The fuel injector includes an injector body, a fuel pressurization chamber, a nozzle chamber, a needle control chamber, a needle control spill outlet, a fuel inlet, and a nozzle outlet. The present fuel injection system includes a source of intermediate pressure fuel, a low pressure fuel reservoir, a needle valve, a flow control valve, and at least one of the present fuel injectors. The method of injecting fuel consists of the steps of injecting fuel at an intermediate pressure at least in part by fluidly connecting the injector's nozzle chamber to an intermediate fuel source, and injecting fuel at a high pressure at least in part by exposing a pressure intensifying element to the source of intermediate pressure fuel.

Common rail injector with separately controlled pilot and main injection

The present invention relates to engines having common rail fuel injection systems. In traditional common rail fuel injection systems, each fuel injector utilized by the fuel system includes its own solenoid. These individual solenoids must cooperate to ensure that the proper amount of fuel is being injected from each injector at the proper time. Having individual solenoids requires a multiple number of moving electrical components. In contrast to the traditional common rail fuel injection system, the fuel injection system of the present invention includes fuel injectors that are controlled in operation by a common electronic actuator that is positioned remote from the fuel injectors. Therefore, the present invention reduces the number of moving electrical components in the fuel injection system by reducing the need for individual solenoids for each fuel injector.

Fuel injection system with common actuation device and engine using same

In hydraulically actuated fuel injectors that utilize lubricating oil as the actuation fluid, various components within the injector body must move relatively short distances at high rates of speed in a wetted oil environment. When the oil is at a relatively low temperature, its relatively high viscosity coupled with relatively small size of these components can cause stiction problems to occur. Stiction occurs where the moveable component comes in contact with the body when it rests against its stop. The highly viscous oil can tend to cause the component to resist breaking free of its stop surface such that the fuel injector may be inhibited in performing adequately, especially during cold start conditions. These potential stiction problems are reduced by including a raised surface feature on one or both of the component and body in order to reduce the potential contact surface area.

Hydraulic device with anti-stiction features

A hydraulically actuated fuel injection system according to the present invention comprises at least one hydraulically actuated fuel injector that includes an injector body that defines a fuel pressurization chamber. A pumping element having a stepped top is movably mounted in a pumping bore defined by the injector body, wherein the pumping element defines at least one internal passageway. The pumping element is movable a distance between a first position and a second position. A spill passage defined by the injector body is open to the fuel pressurization chamber via the at least one internal passageway over a portion of the distance.

Hydraulically-actuated fuel injector having front end rate shaping capabilities and fuel injection system using same

The present invention relates to engines having common rail fuel injection systems. In traditional common rail fuel injection systems, each fuel injector utilized by the fuel system includes its own solenoid. These individual solenoids must cooperate to ensure that the proper amount of fuel is being injected from each injector at the proper time. It is believed in the art that a reduction in the number of moving or electrical components in the fuel injection system can improve robustness of the system. Therefore, the fuel injection system of the present invention includes fuel injectors that are controlled in operation by a common electronic actuator that is positioned remote from the fuel injectors.

A method of adjusting performance of an electronically controlled hydraulic system comprises the initial step of providing at least one electronically controlled hydraulic device having a control valve member operably coupled to an electronic actuator. The control valve member impacts a seat when the device is activated and de-activated. The electronically controlled hydraulic device is then activated according to an activation profile. The seat impacts of the control valve member are detected and recorded. The detected seat impact characteristics are compared to expected seat impact characteristics. A subsequent activation profile is then changed if the detected seat impact characteristics are substantially different from the expected seat impact characteristics

Method and system to monitor and control the activation stage in a hydraulically actuated device

A fuel injector includes an injector body that defines a low pressure space, a trapped volume and a fuel pressurization chamber in fluid communication with a nozzle outlet. A needle valve member is positioned in the injector body and moveable between an inject position in which the fuel pressurization chamber is opened to the nozzle outlet, and a closed position in which the nozzle outlet is blocked to the fuel pressurization chamber. The needle valve member includes a lifting hydraulic surface exposed to fluid pressure in the fuel pressurization chamber, and a closing hydraulic surface exposed to fluid pressure in the trapped volume. At least one of the injector body and the needle valve member define a pressure decay passage extending between the trapped volume and the low pressure space.

Pressure decay passage for a fuel injector having a trapped volume

A pressure control system for controlling output pressure of a variable-displacement hydraulic pump used with a hydraulically-actuated electronically-controlled injector fuel system and method of operation is disclosed. The control system comprises a variable-displacement hydraulic pump with a control element adjustable to a range of positions which controls an output of the pump. The control system additionally includes positioning means for positioning the control element responsive to pressure differences between the fluid reference chamber and the output port. Electronic valve means regulates a pressure of hydraulic actuating fluid in the fluid reference chamber. The electronic valve means is electronically connected with the electronic control means to receive the output signal. A change in the output signal to the electrical valve means produces a change in the pressure of the hydraulic actuating fluid in the fluid reference chamber, thereby causing the positioning means to operably position the control element to change the output of the pump.

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Bloomington, IL, United States of America

Chetan J Desai