Nippondenso Co., Ltd.

Toshimi Matsumura

Akira Masuda

Masahiko Miyaki

Norio Omori

Takashi Hasegawa

Hisamitsu Yamazoe

Takahiro Hayakawa

Hisanori Kobayashi

Isao Osuka

Takashi Arimura

Shuji Sakakibara

Shinya Sumitani

Hideya Fujisawa

Sinya Sumitani

Hitoshi Tomishima

Kiyotaka Nishiura

A common-rail fuel injection system for an engine includes a fuel injection device for injecting high pressure fuel from a common rail into the engine. A pumping chamber is connected to the common rail. A fuel feed device serves to feed fuel to the pumping chamber. A plunger moves upward and downward in accordance with rotation of an output shaft of the engine. The plunger defines a part of the pumping chamber. A relief valve serves to selectively return fuel from the pumping chamber to a low pressure side via a fuel return passage. The relief valve is urged toward its closed position by a pressure of the fuel in the pumping chamber. A valve closing device serves to close the relief valve. A fuel pumping control device serves to drive and control the valve closing device at a given timing to close the relief valve, thereby enabling a pressure in the pumping chamber to increase in accordance with upward movement of the plunger and pumping a given amount of fuel from the pumping chamber to the common rail. An engine speed detecting device serves to detect a rotational speed of the output shaft of the engine. In cases where an engine rotational speed detected by the engine speed detecting means is equal to or higher than a predetermined reference speed, a fuel feed suspending device serves to suspend fuel feed to the pumping chamber by the fuel feed means.

Common-rail fuel injection system for an engine

A system for correcting for atmospheric pressure without using an atmospheric pressure sensor. A single pressure sensor measures air pressure in the intake manifold of a fuel injected engine. A control unit controls the fuel amount and injection timing in accordance with various engine parameters. The intake pressure at a predetermined time is estimated as being indicative of atmospheric pressure. This intake pressure may be further corrected to provide a better estimate. When the engine operates at a low speed and high load, this pressure data is also indicative of atmospheric pressure. The amount of fuel to be injected and the ignition timing can be controlled using this updated atmospheric data. This provides better operation of the system.

Method and apparatus for estimating an atmospheric pressure based on an

In a fuel amount control apparatus arranged to determine the amount of fuel to be fed to respective cylinders so that the scattering in torque generation throughout the cylinders is suppressed, the amount of correction which is either added to or subtracted from a basic fuel amount, is computed such that a sum total of fuel amount correction factors substantially equals zero. To this end the sum total of the correction factors is first computed and is then checked whether an absolute value of the sum total is greater than a predetermined value. When greater, a given amount is either added to or subtracted from correction factors respectively provided for respective cylinders.

Apparatus and method for controlling amount of fuel injected into engine

In a diesel engine control system, an intake air density compensation system is provided for compensating the control amounts of a diesel engine in accordance with the variations of intake air density. The variation amount of the intake air density is indicated by the difference between the control input amount obtained in accordance with an ignition timing closed loop control and the control amount obtained in accordance with an ignition open loop control. The various control amounts of the diesel engine is compensated on the basis of the difference so that the diesel engine is ensured to be optimally operated irrespective of the variations of intake air density.

Intake air density compensation on the basis of ignition timing for

Fuel amount control apparatus arranged to determine the amount of fuel to be fed to respective cylinder so that the scattering in torque generation throughout the cylinders is suppressed. Correction amounts are first obtained during idling, and these correction amounts are then modified using at least one engine parameter so that they can be used not only in idle state but also other operating states. To this end, a correction factor is computed using engine speed or the like so as to modify the correction amounts thereby. As a result, a basic fuel amount is corrected by correction factors provided for respective cylinders where the correction factors are further modified to be suitable for any engine operating conditions, providing smooth rotation without uncomfortable vibrations.

Method and apparatus for controlling amount of fuel injected into engine

A single pressure sensor is provided to measure the air pressure in the intake manifold of a fuel injection engine. An electronic control unit having a microcomputer is provided to control the fuel amount and ignition timing in accordance with various engine parameters including the engine rotational speed and the intake pressure. The intake pressure is first measured before the engine is started so that the data of this pressure can be used as data indicative of atmospheric pressure. During operation of the engine, the pressure data may be used as normal intake pressure data. However, when the engine operates at a low speed and under high load, the pressure data is used as data indicative of the atmospheric pressure with slight correction. The amount of fuel to be injected and ignition timing thus controlled with updated data of atmospheric pressure, and therefore, undesirable phenomena, which are apt to occur when an engine is operated at a high altitude place, are effectively prevented, resulting in desired air/fuel ratio and ignition timing.

Method and apparatus for controlling internal combustion engine

In a fuel injection pump, an engine drives a rotary plunger having an axially extending bore connected to a compression chamber, plural fuel inlet ports alignable with an inlet passage for introducing fuel to the compression chamber, fuel distribution ports for distributing the compressed fuel through the bore to each one of the fuel delivery passages and plural spill ports. A spill-port timing control unit is provided comprising a stator core, a coil wound on thereon, a magnetized ring having a spill groove, and a spring for resiliently maintaining the ring in a reference angular position with respect to the stator core. The magnetized ring is mounted on the plunger so that it can rotate from the reference angular position to an angularly displaced position in proportion to the magnetic flux of the coil to align the spill groove of the ring with each spill port of the plunger to create a passageway through which the compressed fuel is allowed to escape at the termination of fuel injection.

Fuel injection pump having a compact spill-port timing control unit

The engine speed is periodically detected at every predetermined crankshaft angles for obtaining a plurality of engine speed data whose number equals an integral multiple of the number of cylinders of an internal combustion engine. Either maximum or minimum values among the plurality of engine speed data is determined, and such operations are repeated for a duration covering all power strokes within all the cylinders, thereby obtaining a plurality of sets of engine speed data. Then the order of engine speed data giving the maximum or minimum value within each set is obtained, and majority decision is effected to determine which order of data gives the maximum or minimum most frequently throughout all the sets. The difference between the maximum and minimum values is obtained for each set, and the amount of fuel to be supplied to the engine is controlled so that the difference becomes common to all the cylinders. The fuel amount control may be effected by means of an actuator which controls the position of a spill ring of a distributor injection pump.

A distributor type fuel-injection pump according to the present invention is provided with a rotor which is rotated by an engine. The rotor has a pair of plungers slidable in the radial direction of the rotor, and a fuel pumping chamber is defined between the plungers. The rotor is surrounded by a cam ring which reciprocates the plungers as the rotor rotates, thereby sucking fuel into the fuel pumping chamber and pressurizing the fuel therein. The fuel pressurized in the fuel pumping chamber is distributed to individual cylinders of the engine. A plurality of spill holes are formed in the rotor, communicating with the fuel pumping chamber and opening to the outer peripheral surface of the rotor. A control sleeve to open and close the spill holes is axially slidably fitted on the rotor. First and second spill grooves capable of communicating with the spill holes are formed on the inner peripheral surface of the control sleeve. The first and second spill grooves open or close the spill holes to define the timing for the start of fuel delivery in the fuel pumping chamber and the timing for the end of fuel delivery, thereby determining the amount of fuel delivery.

Distributor type fuel-injection pump for distributing fuel to cylinders

In a fuel injection control system for multi-cylinder internal combustion engines, the speed of the engine is monitored and sampled at predetermined angular intervals of engine revolution to detect instantaneous engine speed values identifiable by individual cylinders. From the successively detected instantaneous speeds is derived an average value which is used as a reference for the instantaneous speed values to detect their deviations therefrom. Cylinder-to-cylinder variations in engine speed are minimized by metering the fuel according to the individually derived engine speed deviations.

Engine control system and method for minimizing cylinder-to-cylinder

Fuel injection pump of the type arranged to inject fuel into engine cylinders with the fuel flow being controlled by an electromagnetic valve, comprises a rotor arranged to rotate in timed relation to engine rotation, and a shuttle movably received in an axial bore made in the rotor. Opposite sides of the shuttle define first and second chambers within the axial bore, where the first chamber is used as a compression chamber to pressurize fuel introduced therein via the electromagnetic valve to inject the same into engine cylinders, and the second chamber is communicable with a low pressure fuel reservoir. Fuel is fed into the first and second chambers during an intake stroke or mode, and then the second chamber fuel is pressurized by means of an inner cam mechanism so that the shuttle moves toward the first chamber to pressurize the fuel therein, thereby injecting the fuel during a compression stroke. When the shuttle has been moved toward the first chamber beyond a predetermined position, the second chamber communicates with the low pressure fuel reservoir via a by-pass, lowering fuel pressure in the second chamber to terminate injection. The amount of fuel injected into cylinders is controlled by the stroke of the shuttle toward the first chamber, which stroke is initially determined by the energizing interval of the electromagnetic valve.

Fuel injection pump for internal combustion engine

In a fuel injection system having a fuel injection pump of distribution type with an electromagnetic valve controlling the communication between a spill port and a lower pressure fuel chamber, the closing duration of the electromagnetic valve is controlled by a computer so that the closing duration is defined as the sum of prestroke time and actual injection time which are both prestored in one or more memories. The actual injection time is controlled in accordance with engine operating condition, while the prestroke time may also be controlled by manually setting the same or by way of a feedback control. The sum, which defines the closing duration of the electromagnetic valve, may be limited by a maximum value, which may be manually adjustable, so as to prevent excessive fuel flow. The prestroke time may be uniformly controlled through all the cylinders or may be independently controlled for respective cylinders.

Fuel injection amount control

In a feedback control system for air/fuel ratio control of an internal combustion engine, in which an integration correcting amount is derived from the output signal of a gas sensor indicative of the concentration of an exhaust gas component, and an engine condition correcting amount read out from a memory is arranged to be renewed in accordance with the integration correcting amount so as to effect learning correction, fuel vapor evaporated in a fuel tank is selectively fed via a canister to the engine by controlling an electromagnetic valve. When the engine is in a predetermined operational condition, the electromagnetic valve is energized to disable a fuel vapor supply system. The learning correction is performed only when the fuel vapor supply system is disabled so that the value of the engine condition correcting amount is not affected by a rich mixture caused by the fuel vapor from the canister.

Closed loop air/fuel ratio control of i.c. engine using learning data

In an internal combustion engine, a basic fuel injection pulse width is calculated by parameters such as the engine speed and the intake-air quantity. The basic pulse width is compensated for by an integration compensation factor and a learning correction factor so as to obtain a desired air-fuel ratio. A predetermined number of integration compensation factors are sampled at every air-fuel ratio transition, and the mean value thereof is calculated. The learning compensation factor is corrected in accordance with the mean value of the predetermined number of integration compensation factors.

Method and apparatus for controlling the air-fuel ratio in an internal

The idle speed of an internal combustion engine is controlled in response to a variable ignition timing control signal from a microcomputer. The microcomputer derives this control signal as a function of the magnitude of engine speed variation which occurs during engine idle periods to cause the ignition timing to vary quickly in response to a transitory engine load variation. An auxiliary air delivery system may be advantageously incorporated in the idle speed control system to cooperate with the ignition timing control in response to the engine speed variation.

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Aichi, Japan

Toshimi Matsumura