Abstract: A device for driving a piezoelectric element comprising a power condenser for charging the piezoelectric element. When the discharging operation of the piezoelectric element is started, the piezoelectric element is initially discharged to the high voltage side terminal of the power condenser via a discharging coil and then discharged to the ground via the discharging coil. When the discharging operation is carried out, the voltage at the terminal of the piezoelectric element drops to a minimum voltage. The start time of the discharge to the ground is controlled so that the minimum voltage becomes equal to a predetermined negative voltage.

Abstract: A device for controlling a fuel feed pump comprising a fuel spill passage and a spill control valve arranged in the fuel spill passage. The spill control valve is controlled by the pressure of fuel in a pressure chamber, and the pressure of the pressure chamber is controlled by the piezoelectric element. When the piezoelectric element is driven, the pressure of the pressure chamber is increased, and thus the spill control valve is closed. When the engine speed is high, the piezoelectric element is driven at each 360 degrees of rotation of the crankshaft. Conversely, when the engine speed is low, the piezoelectric element is driven at each 120 degrees rotation of the crankshaft.

Abstract: A fuel injection valve includes a fuel swirl generation device, a main fuel injection hole having a comparatively large diameter, and a subsidiary fuel injection hole having a comparatively small diameter. The inclination of the main fuel injection hole with respect to an axis of the fuel injection valve is small so that a fuel swirl remains in the fuel injected therethrough. The inclination of the subsidiary fuel injection hole is great so that the swirl operates so as to push out the fuel through the subsidiary fuel injection hole. The fuel injected through the main fuel injection hole spreads due to the centrifugal force acting on the swirling fuel without depending on an intake gas swirl. The fuel injected through the subsidiary fuel injection hole has a strong penetrating force and can reach the vicinity of a spark plug. This improves ignition without depending on an intake gas swirl. Thus, good combustion is obtained over an entire operation range of a direct fuel injection type engine.

Abstract: In an apparatus for driving a piezoelectric element used for closing and opening a valve member, a first-step voltage is applied to the piezoelectric element to move the valve element near to a valve seat, and thereafter, a second-step voltage higher than the first-step voltage is applied to the piezoelectric element to seat the valve element securely on the valve seat.

Abstract: In an apparatus for driving a piezoelectric element to close and open a valve member by expanding and contracting a volume of a pressure chamber, at an initial stage of a closing state of the valve member, a higher voltage than a conventional charging voltage or a lower voltage than a conventional discharging voltage is applied to the piezoelectric element, to thus create an initial large closing force at the valve member.

Abstract: A fuel injection valve includes a fuel swirl generation device, a main fuel injection hole having a comparatively large diameter, and a subsidiary fuel injection hole having a comparatively small diameter. The inclination of the main fuel injection hole with respect to an axis of the fuel injection valve is small so that a fuel swirl remains in the fuel injected therethrough. The inclination of the subsidiary fuel injection hole is great so that the swirl operates so as to push out the fuel through the subsidiary fuel injection hole. The fuel injected through the main fuel injection hole spreads due to the centrifugal force acting on the swirling fuel without depending on an intake gas swirl. The fuel injected through the subsidiary fuel injection hole has a strong penetrating force and can reach the vicinity of a spark plug. This improves ignition without depending on an intake gas swirl. Thus, good combustion is obtained over an entire operation range of a direct fuel injection type engine.

Abstract: A fuel injection control device comprising a fuel injector driven by a piezoelectric element. The piezoelectric element is charged with a electrons by using an LC resonant circuit, and the electrons charged in the piezoelectric element are discharged by using an LC resonant circuit. The piezoelectric element is driven before the regular injection is begun.

Abstract: A fuel injector comprising a piston actuated by a piezoelectric element. A pressure control chamber is formed between the piston and the top face of the needle and connected to a high pressure fuel source via a fuel passage having a restricted flow area. The pressure control chamber is filled with fuel under pressure. The rear face of the piston, which is positioned opposite to the pressure control chamber, is exposed to a high pressure fuel chamber filled with fuel under pressure. The driving force acting on the piston due to the pressure of fuel in the pressure control chamber is cancelled by the driving force acting on the piston due to the pressure of fuel in the high pressure fuel chamber.

Abstract: In a drive circuit for electrostrictive actuators provided to fuel injection valves in an internal combustion engine, the drive circuit is constituted by a capacitor connected to a direct current voltage source; a switching element connected to the capacitor and used for charging; a first inductor connected to the switching element and used for charging; a plurality of piezoelectric elements used as the electrostrictive actuator; a plurality of other switching elements each connected to each of the piezoelectric elements and used for discharging; a plurality of diodes each connected to each of the piezoelectric elements and used for clamping; and a second inductor connected to each of the piezoelectric elements through each of the switching elements and used for discharging; wherein, at the time of charging, all of the piezoelectric elements are simultaneously charged by turning ON the switching element for charging, and at the time of discharging, predetermined piezoelectric elements are sequentially dischar

Abstract: An apparatus and method for detecting an intake air mass flow rate using a Karman vortex air flow arranged in an intake passage of an internal combustion engine, in accordance with the formula:.gamma.(x)=.gamma.(760).times.V.sub.p (x)/V.sub.p (760)where .gamma.(x) is an intake air density to be obtained; .gamma.(760) is the air density under standard atmospheric pressure, V.sub.p (x) is the amplitude value of the analog signal obtained from the Karman vortex air flow sensor; and V.sub.p (760) is the amplitude value of the analog signal under standard atmospheric pressure.

Abstract: The pulse-width of the fuel injection signal is controlled, depending upon the running speed and the intake manifold pressure, and corrected by the transient correction factor, which is determined in accordance with the transient operating condition, and the A/F correction factor, which is determined the air-fuel ratio condition. The map used for obtaining the transient correction factor from the transient operating condition is corrected depending upon the converging state of the A/F correction factor by the learning control operation.

Abstract: A fuel injection control apparatus having a pressure detection device for detecting pneumatic pressure in an intake manifold of an internal combustion engine comprises a pressure transducer and a low-pass filter, electrically connected to the transducer, for transmitting an electrical signal from the transducer below a cutoff frequency which is determined to be a frequency equal to or lower than 40 Hz.

Abstract: Disclosed is a device for injecting fuel into an intake air supply passage which is communicated with the combustion chambers of an internal combustion engine.The device comprises: a swingable throttle shaft having a hole formed therein along a longitudinal axis thereof and traversing an intake air supply passage; a throttle valve plate fixed to the throttle shaft for throttling the intake air supply passage so that the throttle valve plate can vary the opening of the air supply passage due to the swing of the throttle shaft; and a fuel injection outlet portion formed at the proximity of the surface of the throttle valve plate and communicated with one of the hole. Fuel supplied from the fuel injection outlet portion is uniformly admixed with the air flow which is caused to contract by the throttle valve plate.

Abstract: A fuel-air mixture supply system comprising a Venturi portion formed on the inner surface of a cylindrical suction system having a throttle valve therein, at least one fuel injection port provided in the Venturi portion and open into the suction system, an atomizing chamber located adjacently to the fuel injection port in a co-axial manner to the fuel injection port and having a nozzle to make the atomizing chamber communicate with the fuel injection port, a fuel injection valve connected to the cylindrical suction system to inject the fuel into the atomizing chamber at a predetermined pressure and an air bleed passage making the portion above the throttle valve in the suction system communicate with the atomizing chamber. The fuel injected into the atomizing chamber from the fuel injection valve is atomized by the air drawn into the chamber from the suction system through the air bleed passage.