701 results about "Rail pressure" patented technology

Methods and systems are provided for operating an engine fuel system including a low pressure pump and a high pressure pump. During conditions when direct injection is not requested, a fuel rail pressure is maintained by the low pressure pump and fuel is port injected. Further, a stroke amount of the high pressure pump is adjusted to maintain an outlet pressure of the high pressure pump just below the fuel rail pressure. By maintaining fuel flow within the high pressure pump when high pressure pump operation is not required, and without flowing fuel from the high pressure pump outlet into the fuel rail, the high pressure pump may be cooled and lubricated without affecting the fuel rail pressure.

A fuel injection system for supplying pressurised fuel to a fuel injector (200) comprises an accumulator volume (606) for supplying fuel at rail pressure (P1) to the fuel injector (200) through a rail fuel supply passage (608) and a fuel pressurising arrangement (604) for supplying fuel at a selected pressure greater than rail pressure (P2) to the fuel injector (200) through a pressurised fuel supply passage (614). A fuel shut-off valve (618) is provided in the system which is operable between a closed position in which fuel is retained within the pressurising arrangement (604) and an open position in which pressurised fuel is supplied to the injector (200) from the pressurising arrangement (604) during an injection of fuel from the rail fuel supply passage (608). Operating the shut-off valve in this way provides a boost in the fuel pressure delivered during an injection event.

A gaseous-fuelled internal combustion engine and a method of engine operation improve combustion stability and reducing emissions of NOx, PM, and unburned hydrocarbons. The method comprises fuelling an internal combustion engine with hydrogen and natural gas, which can be directly injected into the combustion chamber together or introduced separately. Of the total gaseous fuel delivered to the engine, at least 5% by volume at standard temperature and pressure is hydrogen. For at least one engine operating condition, the ratio of fuel rail pressure to peak in-cylinder pressure is at least 1.5:1. A fuel injection valve introduces the gaseous fuel mixture directly into the combustion chamber. Two separate fuel injection valves could also introduce the methane and hydrogen separately. An electronic controller controls timing for operating the fuel injection valve(s). The engine has a preferred compression ratio of at least 14:1.

A system and method for controlling multiple fuel injections during a single combustion cycle for a multiple cylinder internal combustion engine having a common rail fuel distribution system determine the beginning of injection for the pilot and main injections based on crankshaft position while post injections are based on the main injection timing and an injector turn off delay determined using actual rail pressure. A rail pressure setpoint is determined based on current engine operating conditions including one or more fluid temperatures and current operating mode to provide more accurate injection control.

It is possible to perform a failure diagnosis of a pressure sensor with a simple structure without installing a dedicated circuit for the failure diagnosis.

In a common rail type fuel injection control apparatus, a pressure control valve 12 is provided in a fuel return path from a common rail 1, and a rail pressure detected by a pressure sensor 11 can be controlled to match a target rail pressure through drive control of the pressure control valve 12 by an electronic control unit 4. The target rail pressure is calculated based on operational information of an engine 3. In the common rail type fuel injection control apparatus, learning processing is performed, in which a correction coefficient Cv is stored and updated as a learning value to correct energization characteristics of a median product of the pressure control valves 12 that are stored in the electronic control unit 4. At the same time, it is determined whether the learning value of the correction coefficient Cv is within a predetermined range. When it is determined that it is not within the predetermined range, the pressure sensor 11 is diagnosed as having a failure.

In controlling power supply time, a variation in the fuel injection quantity caused by a variation in the fuel injection rate at the in-cylinder pressure of the engine (detected or estimated value in the running state of the internal combustion engine) relative to the fuel injection rate at a reference in-cylinder pressure (under the condition of an injector characteristic measuring benchmark test), and in addition, a variation in the fuel injection start time is corrected. In the calculation of the variation in the fuel injection quantity, a fuel injection rate changing behavior model in which changing behavior of the fuel injection rate is modeled as a trapezoid is used to calculate the areas of Δq1 and Δq2. The variation in the fuel injection start time Δτd is calculated based on the rail pressure and the variation in the in-cylinder pressure. In this way, there is provided a technology for controlling the fuel injection quantity that changes with a change in the in-cylinder pressure with improved accuracy.

In a common rail operating method and system, an arrangement for controlling the rail pressure is provided with a rail pressure controller including a current control circuit for controlling a suction throttle valve operating current (i) which valve is arranged in the fuel supply line to a high pressure pump supplying high pressure fuel to the common rail. The suction valve operating current control circuit includes a preliminary control value generator which serves also as an emergency control signal generator for the control of the suction valve if an error occurs in the system at least to permit an orderly engine shutdown procedure.

Dynamic health assessment systems and methods related to monitoring fuel flow control are provided. In one embodiment, a method for controlling a system having an engine is provided. The method includes during a no-load condition of the engine, stopping fuel injection by a plurality of fuel injectors of the engine, closing a valve that is operable to control fuel flow to a fuel pump that pumps fuel to a common fuel rail, and setting a degradation condition in response to a fuel rail pressure decay rate of a fuel pressure in the common fuel rail being greater than a decay threshold after a first designated duration.

A method for detecting failures in a fuel system of a motor vehicle including monitoring a feed-forward table of a fuel pump controller that is electrically connected to a fuel pump of the fuel system. The fuel pump controller is electrically connected to a rail pressure sensor, which is coupled to the fuel injector rail. The actual fuel injector rail pressure measured by the rail pressure sensor is compared to a desired fuel injector rail pressure associated with the feed-forward table. The feed-forward table is adjusted if the actual fuel injector rail pressure is less than the desired fuel injector rail pressure. A fuel system error is signaled if an adjusted feed-forward table differs from an initial feed-forward table. A fuel system failure is signaled of the adjusted feed-forward table requires a saturation voltage of the controller.

A method of estimating an injection delay of a fuel injector. A baseline injection delay curve representing an injection delay for a predetermined type of fuel injector is established for a range of rail pressures. At least one test rail pressure for the predetermined type of fuel injector is identified based on the baseline injection delay curve. An injection delay of a selected fuel injector of the predetermined type is measured at the at least one test rail pressure. The injection delay of the selected fuel injector is estimated based on the baseline injection delay curve and the measured injection delay of the selected fuel injector at the identified test rail pressure.

A method for closing a storage tank valve in response to leaks in a fuel line or fuel rail and emptying the tank of a vehicle when no leaks are detected is described. The method includes comparing a tank pressure to a fuel line or fuel rail pressure in order to detect leaks therein and further includes using a dedicated tank pressure sensor to measure the gaseous pressure of the storage tank, and thereby the amount of fuel remaining. In response to leaks in the fuel system, a controller may close an electronic solenoid valve, which reinforces a mechanical excess flow valve, to block the flow of fuel and prevent fuel loss from the gaseous storage tank.

In common rail fuel injection systems, a sensed rail pressure is used to determine control signals to produce desired injection characteristics. Because rail pressure fluctuates, especially during cold start procedures, and because the rail pressure must be sensed before the injection event to be controlled, the accuracy of the timing and quantity of the injection event can be compromised if the rail pressure at the start of the injection event is different from the sensed rail pressure. In order to produce more accurate fuel injection characteristics, the rail pressure is sensed after the end of control signal for an immediately preceeding injection event but at least a predetermined time before the start of control signal for a succeeding injection event. Since the rail pressure is sensed close in time to the succeeding injection event but with adequate time to do control signal determination calculations, the accuracy in quantity and timing of the succeeding injection event can be improved because the quality of the sensed rail pressure is improved.

A common rail fuel injection apparatus for an engine is provided which is equipped with a rail pressure sensor working to measure the pressure of fuel in a common rail, fuel injectors, and a controller. When the operation state of the rail pressure sensor monitored to be unusual, the controller changes the value of electricity supplied to an actuator of one of the fuel injectors to induce a change in a preselected operation characteristic of the engine. Upon appearance of such a change, the controller estimates the value of the rail pressure using the changed value of the electricity and a physical property of balance among forces acting on a valve of one of the fuel injectors which has induced the change in operation characteristic of the engine. The estimated value of the rail pressure is used for subsequent injections of the fuel into the engine.

Methods and systems are provided for restarting an engine when a high pressure fuel pump is degraded. In response to an indication of high pressure fuel pump degradation, fuel may be injected during an intake stroke, rather than a compression stroke, for a selected number of combustion events since the engine restart. By shifting to an intake stroke injection, the engine may be started even when sufficient fuel rail pressures are not available.