Denso Corporation

Nippon Soken, Inc.

Daiji Ueda

Hiroki Tanada

Motoya Kanbara

Fumiaki Arikawa

Jun Kondo

Akitoshi Yamanaka

Tooru Taguchi

Toshiaki Hijima

Naoki Toda

Hitoshi Maegawa

Nao Ogasawara

Masahiro Watanabe

Yuya Kitagawa

Satoshi Sugawara

A fuel injection control device has a valve opening control portion which opens a control valve by electrically charging a piezoelectric element, and a valve closing portion which closes the control valve. The valve opening control portion includes a first rising control portion, a pause control portion and a second control portion. The first rising control portion increases a charge amount of the piezoelectric element during a first rising period. The pause control portion pauses an increase in the charge amount of the piezoelectric element during a pause period after the first rising period. The second rising control portion increases the charging amount of the piezoelectric elements again during a second rising period after the pause period. The pause period includes a period of immediately before the control valve is opened.

Fuel injection control device

The pressing part includes an abutment part capable of being in contact with the inner peripheral surface of the pressing passage, and a depressed opposite part that is opposed to the exhaust port at a position away from the exhaust port in a perpendicular direction perpendicular to the displacement direction due to an outer peripheral surface of the pressing part recessed from the abutment part even when the abutment part is in contact with the inner peripheral surface of the pressing passage. When the abutment part is in contact with the inner peripheral surface of the pressing passage, a depression dimension of the depressed opposite part relative to the abutment part is set, such that an amount of fuel discharged from the valve chest is defined by the exhaust throttle part instead of a gap between the depressed opposite part and the inner peripheral surface of the pressing passage.

Fuel injection device

A fuel injection device has a valve body, a drive portion, a nozzle needle, and a control valve body. The valve body defines a control chamber, a valve chamber and a low pressure communication passage. The nozzle needle is displaced due to a fuel pressure variation in the control chamber to open/close an injection port. When the control valve body sits on an upper seat surface, a low pressure communication passage is closed so that the valve chamber is fluidly disconnected from the low pressure chamber. The control valve body defines a gap restriction on the upper seat surface. A flow passage area of a sub orifice provided to the low pressure communication passage is smaller than a flow passage area of the gap restriction.

An enclosure member includes a throughhole that penetrates a cover portion. The cover portion includes a blocking portion that receives an abutment by a wall portion to close an opening of an outflow passage with respect to spaces outside of the enclosure member. The blocking portion is provided so as to surround an opening of the throughhole, and the throughhole is in communication with the outflow passage even when the blocking portion is abutting the wall portion. Further, a spring is outside of a back pressure chamber to bias the enclosure member. The enclosure member itself blocks outside spaces from the back pressure chamber, so the expenditure of high pressure fuel may be controlled, and an injection hole may be opened and closed by a needle.

Injector

When a main injection is performed, a first timing that is a time earlier than a second timing is selected as the valve opening starting timing, and a first period that is the period of time shorter than a second period is selected as the control period. Also, when a pilot injection is performed, the second timing that is the time later than the first timing is selected as the valve opening starting timing, and the second period that is the time longer than the first period is selected as the control period. Thus, in an injector with increased valve opening responsiveness, the valve opening behavior of a control valve of the injector in fuel injection with a minute injection quantity can be stabilized without replacing a control device, particularly an EDU with that of a large current specification.

A fuel injection valve includes a body including a first chamber that supplies fuel of a first pressure, a second chamber that supplies fuel of a second pressure, and an injection hole, a valve chamber member including a valve chamber connectable to the first chamber and the second chamber, a control chamber member including a control chamber connectable to the first chamber, a needle pressed by pressure of fuel in the control chamber in a direction that causes fuel injection from the injection hole to stop, an actuator, a valve element that selectively connects the first chamber, second chamber, and the valve chamber according to the actuator extending and contracting, and a transmission mechanism that when the actuator extends, transmits the force to the needle as a force in a direction that causes fuel to be injected from the injection hole.

Fuel injection valve and fuel injection valve controller

A high-pressure-side valve portion makes contact with and moves from a high-pressure seat surface formed in a body to control communication between a control chamber communication passage and a high-pressure passage. A low-pressure-side valve portion makes contact with and moves from a low-pressure seat surface formed in the body to control communication between an exhaust passage and a second intermediate chamber. A releasing portion in the high-pressure-side valve portion communicates with the control chamber communication passage when the high-pressure seat surface is in contact with the high-pressure-side valve portion to block the control chamber communication passage from the high-pressure passage. A valve element internal passage is formed in the valve element to communicate the releasing portion with the second intermediate chamber.

Fuel injection valve

A valve cylinder partitions a first intermediate chamber from a second intermediate chamber. A first valve element in the first intermediate chamber includes a tubular high-pressure-side valve portion to control communication between a control chamber communication passage and the first intermediate chamber. A second valve element in the second intermediate chamber includes a low-pressure-side valve portion to control communication between an exhaust passage and the second intermediate chamber. A columnar rod portion located between the first valve element and the second valve element is slidably held at a cylinder hole of the valve cylinder. An internal passage communicates the control chamber communication passage with the second intermediate chamber. The high-pressure-side valve portion has an outer diameter greater than an outer diameter of the rod portion.

It is equipped with an injector bodywhich has formed therein high-pressure paths, andthrough which high-pressure fuel flows to a spray hole and stores therein a piezo-actuator(i.e., an opening/closing mechanism) and a back-pressure control mechanism(i.e., an opening/closing mechanism) which open or close the spray hole, and a fuel pressure sensorinstalled in the bodyto measure the pressure of the high-pressure fuel. The bodyhas formed therein a branch pathdiverging from the high-pressure pathsandto deliver the high-pressure fuel to the fuel pressure sensor

Growing community of inventors

Kariya, Japan

Daiji Ueda