Zexel Gmbh

Diesel Kiki Co., Ltd.

Bosch Automotive Systems Corporation

Yoriyuki Takekawa

Hidekazu Oshizawa

Nobukazu Takagi

Tsuneo Adachi

A check valve () and a booster () are inserted in parallel in a supplied fuel line () connecting a common rail () and an injection valve (), a piston (E) of a hydraulic circuit () is driven for positioning by a piezoelectric actuator (PA-), the pressures in a chamber (Db) of the booster () and the pressure in a fuel chamber (G) of the injection valve () are selectively lowered by controlling the alignment state between ports (Eb), (Ec) provided in the piston (E) to communicate with a low-pressure portion and an openingAa of a first chamberA and an opening (Ba) of a second chamber (B) of cylinder (C), whereby the pressure of the fuel supplied to the fuel reservoir (B) of the injection valve () is rapidly switched to one or the other of high-pressure fuel from the common rail () and pressure-boosted high-pressure fuel from the booster ().

Fuel injection device

A device for driving a DC brushless motor by outputting commutation control signals based on voltages induced in the drive windings includes a position detection circuit having low-pass filter circuits that remove a chopping frequency component and have a phase lag of 60-90.degree. at maximum motor rotational speed, a rotational frequency computing section, and a phase correction amount computing section that effects a computation based on the rotational frequency computed by the rotational frequency computing section to set the commutation time point to produce a 30.degree. phase lag in a rotational speed range in which the phase lag falls in the range of 0.degree. to less than 30.degree. and to produce a 90.degree. phase lag in a rotational speed range in which the value of the phase lag falls in the range of 30-90.degree.. The device achieves high efficiency at optimum commutation timing in the high rotational speed region and suppresses vibration and noise in the low rotational speed region.

Method and device for driving DC brushless motor

A motor driving apparatus PWM-controls a DC voltage from a rectifying unit according to a rotation speed setting information, and drives a motor by voltage pulse chooped by PWM. The rectifying unit is controlled so that a full-wave rectification is performed when the motor runs at a rotation speed below a prescribed rotation speed and a voltage-doubler rectification is performed when the motor runs at a rotation speed above the prescribed rotation speed. On the other hand, in case a motor drives a compressor of an air-conditioning system, the rectifying unit is controlled so that the full-wave rectification is performed when the air-conditioning system is a cooling operation and the voltage-doubler rectification is performed when the air-conditioning system is a heating operation. When the rectifying unit is controlled for the full-wave rectification, even if a width of voltage pulse given to the motor is decreased, a voltage value of the voltage pulse is half as compared with the voltage-doubler rectification. Hence, since a motor current is small and its current variation is also small, a hysteresis loop due to a variation in magnetic flux becomes small and an iron loss is reduced. When the rectifying unit is controlled for the voltage-doubler rectification, since a DC voltage which is the double of that of the full-wave rictification is supplied, the motor capacity can be increased.

Motor driving apparatus for pulse-width modulation controlling a DC

In order to enable switching of a direct current brushless motor to sensorless operation in a very short time by a device of simple configuration, the application to a commutator section of external sync signals for accelerating the rotor is stopped upon passage of a fixed time after the start of application. The fixed time is set to one necessary and sufficient for the rotor to reach a speed sufficient for enabling sensorless operation. After the application is stopped, the commutator section is controlled to commutate drive current to the drive windings according to the rotor position by commutation control signals output by a position feedback drive signal generator using sensorless signals from a position detection circuit based on back electromotive force voltages generated in the drive windings.

A driving apparatus for a commutatorless DC motor decides a next commutation period based on a difference of a reference zero-cross time and an actual zero-cross time such that a rising or falling edge of induced voltage signals is generated at the reference zero-cross time. Rising and falling edges of the induced voltage signals represent zero-cross points of induced voltages that are generated at each phase of drive windings. The actual zero-cross time is an actual time width from a start of a current commutation period till the generation of a rising or falling edge of the induced voltage signals. The reference zero-cross time is a desirable time width from the start of the current commutation period until a rising or falling edge of the induced voltage signals should be generated. The driving apparatus calculates an integrated value of the next commutation period by an integral computation based on the difference and an integrated value of the current commutation period, and decides the next commutation period by a proportional computation based on the difference and the integrated value of the next commutation period. Driving current of each phase of the drive windings is commutation controlled based on the decided commutation period.

Driving apparatus for a commutatorless DC motor

A display system for a vehicle is provided with a fluorescent display tube. An anode control circuit outputs a control signal for selecting one or more of anode electrodes of the display tube to output a first control signal in response to which the selected anode electrodes are supplied with a positive voltage to cause the flourescent display tube to make a display. A display condition judging circuit judges whether or not the anode control circuit is outputting the first control signal. A brightness judging circuit judges whether the surroundings of the fluorescent display tube are bright or dark. A filament control circuit outputs a second control signal for energizing a filament of the display tube when said display condition judging circuit judges that the anode control circuit is outputting the first control signal and/or when the brightness judging circuit judges that the surroundings of the display tube are bright. The filament control circuit ceases to output the second control signal when the anode control circuit does not output the first control signal and at the same time when the brightness judging circuit judges that the surroundings of the display tube are dark.

Display system for use in vehicle

A control apparatus for an automobile air-conditioner so constructed as to calculate a target discharge air temperature based on a control parameter determined by the vehicle compartment temperature and the outside air temperature, then control a component of the air-conditioner according to a result of the calculation. The control parameter is obtained by interpolation of experimentally determined reference data with the present vehicle compartment temperature and the present outside air temperature. With this arrangement, a fine temperature control can be achieved.

Growing community of inventors

Higashimatsuyama, Japan

Yoriyuki Takekawa