Nippon Soken, Inc.

Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Denso Corporation

Toyota Jidosha Kogyo Kabushiki Kaisha

Yasuyuki Sakakibara

Toshihiko Igashira

Seiko Abe

Kazuhide Watanabe

Toru Yoshinaga

Yasuhiro Takeuchi

Yukihiro Natsuyama

Hisasi Kawai

Taro Tanaka

Kiyonori Sekiguchi

Shigeiku Enomoto

Moriyasu Gotoh

Masahiro Takigawa

Akihiro Izawa

Hiroshi Yorita

Hidetaka Nohira

Akira Kuno

Masahiro Tomita

Kazuo Shinoda

Yoshihiro Tsuzuki

Yoshimi Natsume

Norihito Tokura

Kazuhiro Sakurai

Eturo Yasuda

Kyo Hattori

Takeshi Tanaka

Eiji Takemoto

Akikazu Kojima

Nobuhiko Koyama

Terutoshi Tomoda

Takehiko Kato

Kazuto Maeda

Sigeru Kamiya

Yasuhiro Fukagawa

Hiroshi Koide

Nobuyuki Murate

Shigeki Daido

Yasutaka Nakamori

Yasufumi Yamada

Mitiyasu Moritugu

Kou Otsuka

Yuzi Ishiguro

Shinichiro Kamohara

Huminori Suzuki

A piezo actuator drive circuit comprises a charging path for charging a piezo stack that can be driven by being charged and discharged, an arithmetic circuit for calculating the charging amount for the piezo stack, and a driving control circuit for comparing the calculated charging amount and a target charging amount and correcting the charging amount during the next charging process according to the difference between the compared charging amounts. A charging current flowing through the piezo stack and a charging voltage applied to it may be measured during a charging process. It is preferable that the calculated charging amount be the amount of energy that is the result of the time quadrature of the product of the measured current and voltage.

Piezo actuator drive circuit

A target fuel injection timing of the fuel injection pump is calculated based on the operating conditions of a diesel engine (Steps 102; 302; 602), while an actual fuel injection timing is calculated based on crank angle signals (Steps 103; 303: 603). Then, a fuel injection timing error (Terr) is obtained based on a difference between the target fuel injection timing and the actual fuel injection timing (Steps 104; 304; 604). To adjust the actual fuel injection timing based on the error (Terr), a rotational position of a roller ring (10) is controlled through a timer piston (21) slidable and housed in a timer device (28) by a hydraulic pressure control valve (27) in response to a pulse actuating signal having a controllable duty ratio (DFIN). The pulse actuating signal having the controlled duty ratio is generated at a predetermined pulse output timing (Steps 208; 406; 706), so that the fuel injection caused by a force feeding stroke of the fuel injection pump is not overlapped with an actual valve-open duration of hydraulic pressure control valve (27) varying depending on the engine speed (N), thereby completely locking the timer piston (21) during the fuel injection.

Fuel injection timing control apparatus for a fuel injection pump and

An injection timing control device for a fuel injection pump includes an oil-pressure control valve for controllably changing the fuel injection timing of the fuel injection pump. The oil-pressure control valve includes a valve cylinder having a valve seat. The valve seat has a first truncated-conical surface. The oil-pressure control valve further includes a valve needle slidably received in the valve cylinder and movable by a control unit. The valve needle has a second truncated-conical surface for engaging with the first truncated-conical surface to close the oil-pressure control valve and disengaging from the first truncated-conical surface to open the oil-pressure control valve. The first and second truncated-conical surfaces, when engaged, form a circular seal line on which the first and second truncated-conical surfaces abut each other. The circular seal line has a diameter which is substantially the same as a diameter of the valve needle. In the oil-pressure control valve, a fuel pressure applied to the valve needle at one axial end thereof is introduced to an opposite axial end thereof for equalizing fuel pressures applied to the valve needle at the opposite ends thereof.

Injection timing control device for fuel injection pump

A common-rail fuel injection system for an engine includes a fuel injector having a nozzle hole. A common rail stores high-pressure fuel. The common rail is connected to the fuel injector to feed the high-pressure fuel thereto. A movable nozzle needle disposed in the fuel injector blocks and unblocks the nozzle hole in accordance with movement thereof. A back pressure control chamber defined in the fuel injector is connected to the common rail to receive the high-pressure fuel therefrom. The nozzle needle is urged in a direction of blocking the nozzle hole in response to a pressure in the back pressure control chamber. A fuel chamber defined in the fuel injector is connected to the common rail to receive the high-pressure fuel therefrom. The nozzle needle is urged in a direction of unblocking the nozzle hole in response to a pressure in the fuel chamber. A fuel-pressure-responsive 2-way valve controls the pressure in the back pressure control chamber. An electromagnetic valve changes a state of the fuel-pressure-responsive 2-way valve. The fuel injector and the fuel-pressure-responsive 2-way valve are combined into a single unit. The electromagnetic valve is separate from the fuel injector.

Common-rail fuel injection system for an engine

A solenoid valve provided with a relief passage by means of which a high-pressure side and a low-pressure side communicate with each other for use, for example, in combination with a fuel injection pump, comprises a valve element capable of being advanced into and retracted from the relief passage, a first compression spring for biasing the valve element in the retracting direction, an armature attached to the rear end of the valve element, an electromagnet for attracting the armature to disconnect the high-pressure side and the low-pressure side from each other by advancing the valve element into the relief passage against the resilience of the first compression coil spring, and a second compression coil spring for holding the armature in a predetermined position close to the electromagnet against the biasing force of the first compression coil spring when the electromagnet is demagnetized.

Solenoid valve

A fuel injector wherein a piston driven by the extension and contraction of a piezoelectric actuator changes the pressure of a working fluid in a variable pressure chamber and back pressure chamber so as to drive a needle valve to open and close a fuel injection hole, wherein undesirable secondary injection after a main injection in prevented by providing a throttle portion for narrowing the communicating passage between the variable pressure chamber and back pressure chamber when the piston moves forward and the needle valve closes the fuel injection hole.

Fuel injector for internal combustion engine having throttle portion

A fuel injection apparatus which, when raising fuel of a low viscosity and a low lubricating ability such as gasoline or methanol to a high pressure by a fuel injection pump and injecting it into a combustion chamber of an internal combustion engine etc., prevents the lubricating oil for the fuel injection pump from being diluted by this fuel by pressurizing a separate working oil with a viscosity and lubricating ability higher than the fuel by the fuel injection pump and raising the pressure of the fuel by a diaphragm apparatus by the pressure of the high pressure working oil and thereby supplies the same to the fuel injector.

Fuel injection apparatus

A fuel vapor purging system includes a container in which a set of divided chambers are formed by partition walls. Absorbent is disposed in the divided chambers. The divided chambers are sequentially connected to form a zigzag passage. Fuel vapor can enter the container from a fuel tank via a vapor line connecting the fuel tank and the container. In the container, an end of the vapor line faces the divided chamber which occupies an end of the set of the divided chambers. In the container, the fuel vapor is absorbed by the absorbent. Air can escape from the container via an opening in the container. The fuel vapor can be separated from the absorbent. The separated fuel vapor can be drawn into a suitable drawing device such as an engine air induction device via a purge line connecting the container and the drawing device. Fresh air can flow into the container via an air inlet provided on the container. Among the divided chambers, at least the divided chamber which occupies the end of the set of the divided chambers has a cross-sectional area equal to or smaller than 40 cm.sup.2.

Fuel vapor purging system

A hydraulic valve drive device for intake/exhaust valves of an internal combustion engine using an oil pump similar to a distributor type injection pump. A plunger rotates and engages in reciprocating motion to pressurize hydraulic fluid taken into a pressure chamber and opens to discharge the same into a hydraulic cylinder of a specific intake/exhaust valve in register with the passage. The intake/exhaust valve maintains its valve lift to continue remaining open when the supply of the hydraulic fluid is stopped, but closes when the plunger rotates so that the passage is communicated with a relief channel and the relief valve opens.

Valve drive device

An internal combustion engine has an evaporated fuel purge system for directly feeding evaporated fuel of a fuel tank into an intake pipe of the engine during the engine is running. This system comprises a purge control valve for opening or closing a flow line which connects an upper space of the fuel tank with the intake pipe, a controller for controlling the operation of the valve, a throttle section formed in series with the purge control valve, and pressure and temperature sensors which are located on the upstream side of the throttle section for detecting a pressure and a temperature of the evaporated fuel. When a value detected by the pressure sensor exceeds a predetermined value of pressure for providing a critical pressure ratio at which a flow rate of the evaporated fuel at the throttle section substantially equals to a sonic velocity, the controller opens the purge control valve to cause a purged flow of the evaporated fuel whose flow rate is constant. Simultaneously, the controller calculates a purged flow rate of the evaporated fuel from the detected values of the pressure and temperature sensors and a time period during which the purge control valve is opened. On the basis of the calculated purged flow rate, a reduction correction is made to an amount of the fuel to be supplied to the engine in order to maintain an air-fuel ratio in the optimum condition. The calculated purged flow rate may be indicated.

Internal combustion engine with evaporated fuel purge system

An electrostrictive actuator which can be used, e.g., in a distributor type fuel injection device of a diesel engine has an electrostrictive actuator for generating an electric charge upon reception of a load and an electric circuit unit connected to the electrostrictive actuator. The electric circuit unit has an electric charge changing means for changing the electric charge of the electrostrictive actuator in the state of generation of electric charge due to a load exerted on the electrostrictive actuator and thereby constricting the electrostrictive actuator, and an electrical charging means for charging the electrostrictive actuator in the state of constriction due to the operation of the electric charge changing means when the load exerted on the electrostrictive actuator is reduced and thereby extending the electrostrictive actuator.

Electrostrictive actuator device and fuel injection device using same

A fuel injection pump including a valve opening and closing an overflow passage formed in a body of the pump to connect a high pressure chamber to a low pressure chamber. The low pressure chamber is provided for reserving low pressure fuel, and the high pressure chamber is provided for pressurizing fuel sent from the low pressure chamber and for discharging the pressurized fuel to fuel injectors. A plunger has intake grooves which open the feed passage to communicate the high pressure chamber with the low pressure chamber on an intake action of the pump. The body of the pump has a feed passage formed therein which connects the high pressure chamber to a control chamber. The pressure in the control chamber is changed by the expansion and contaction of a piezoelectric actuator, and the pressure in the control chamber urges the valve in a direction in which the valve closes the overflow passage. A start and end of a fuel injection period, and a fuel injection ratio (a pilot fuel injection), can be controlled by the opening and closing of the valve.

Fuel injection pump for an internal combustion engine

A fuel injection system in which a fuel injector having a fuel pressure control chamber formed therein to create a pressure which forces a needle valve in the closing direction to open and close the nozzle hole, an accumulator to retain fuel discharged from the nozzle hole, and a fuel injector provided at each of the cylinders of the engine, are connected to the fuel injection pump by a single piping system without utilizing a special distribution mechanism. The volume of the fuel pressure control chamber in the fuel injector can be changed by a piezo-actuator. A check valve is provided at a half way point of the piping which leads the fuel fed under pressure from the fuel injection pump to the fuel injector into the fuel pressure control chamber and the accumulator, so that the fuel is fed through the check valve into the fuel pressure control chamber and the accumulator.

Fuel injector and fuel injection system

A method and apparatus for driving a capacitive-type load using a direct current power source, a charging circuit connected in series to the load, a discharging circuit connected in parallel to the load, and an electric circuit for controlling the charging and discharging circuits, and wherein at least one of the charging and discharging circuits has a primary coil, and a secondary coil coupled to the primary coil restores energy, generated when the charging or discharging is turned OFF, to the power source. This provides a highly efficient driving by a restoration of energy.

Method and apparatus for driving capacitive-type load

A drive circuit for an electrostrictive element actuator for a fuel injection apparatus of a diesel engine. The drive circuit has a condenser adapted to be charged with electric charges generated by the electrostrictive element actuator; a combination of an electric charge transferring switching element and a rectifier element for becoming conductive in a first period and charging electric charges generated by the electrostrictive element actuator to the condenser; and a combination of an electric charge returning switching element and a rectifier element for becoming conductive in a second period, other than the first period, and returning electric charges stored in the condenser to the electrostrictive element actuator.

Drive circuit of electrostrictive element actuator in diesel engine fuel

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Nishio, Japan

Yasuyuki Sakakibara