Nissan Motor Company Limited

Iwane Inokuchi

Toshikazu Oshidari

Shigeru Kamegaya

Atsuhiro Sakamoto

Masanari Yanagisawa

Masahiro Honma

A valve includes a valve body forming a first flow passage and a second flow passage that connects to the-first flow passage through a first opening and a seating element forming a bypass passage that connects the first flow passage and the second flow passage. The bypass passage opening has a smaller cross-sectional area than the first opening. The valve also includes a valve control element that can be repositioned to open both the first opening and the second opening, open the second opening while closing the first opening or close both the first opening and the second opening. The bypass passage may allow fluid to drain through the valve to prevent fluid from building up in the valve. If fluid becomes frozen, the valve may become stuck shut. In some embodiments, the bypass passage opens only if the temperature creates a possibility of freezing in the valve.

Valve structure and control techniques

This device diagnoses whether or not a fuel pump which supplies fuel to an engine has failed. The pump includes a plurality of pressure chambers which in turn discharge fuel according to the rotation of an input shaft which turns together with the engine. The supply capacity of the fuel pump when one of the pressure chambers has failed so as not to be able to discharge fuel is set to a value lower than the maximum value of the fuel supply amount which is required by the engine. A mechanism is provided which decides whether or not the fuel supply requirement of the engine is being satisfied, and failure of the fuel pump is diagnosed based upon the result of this decision. Further, accurate diagnosis can be performed by detecting the power output of the engine for each cylinder individually, and by deciding upon fuel supply insufficiency for each cylinder individually according to variation of the output power for each cylinder individually.

Failure diagnosis device for a fuel pump

Fuel is pressurized by the expansion and contraction of a pump chamber defined inside a casing according to the rotation of a power input shaft which penetrates from the outside of the casing into its inside. A first seal member is provided between the casing and the power input shaft and prevents escape of fuel which is inside the casing, and a second seal member is provided in series therewith. Further, leakage of fuel to the outside of the casing from the second seal member is prevented by the provision of a drain conduit which drains fuel which has leaked into a space defined between the first seal member and the second seal member.

Fuel pump

A cam plate pump comprises a pressurizing chamber formed by a bellows which elongates and contracts along a center axis parallel to the input shaft of the pump. The cam plate rotates together with the input shaft, and compresses the bellows via a piston. A mechanism for guiding the piston along the center axis, and a mechanism for blocking the rotational torque acting on the bellows via the piston are provided. These mechanisms prevent a bending load or twisting load from acting on the bellows.

Bellows cam plate pump

A hydraulic pressure supply apparatus includes a variable displacement pump which is controlled to change its discharge flow rate and pressure in accordance with a condition of a load side. The pump is communicated with the load side through a conduit to which an accumulator is communicated through a proportional pressure reducing valve controlled so that its regulating pressure is higher than the pressure required in the load side and is lower than a target discharge pressure of the pump. Furthermore, when the pressure in the conduit is lower than the regulating pressure of the valve, the valve is opened and regulates the pressure in the conduit by allowing higher pressure flow from the accumulator.

Hydraulic pressure supply apparatus

A proportional pressure reducing valve includes a spool having a first end connected to a solenoid and a second end exposed to a feedback chamber. The spool is formed with a groove for allowing a supply port to communicate with an output port when the spool is driven by the solenoid in proportion to solenoid current under balanced condition of an axial force of the solenoid and feedback pressure. The pressure reducing valve further comprises a pressure reduction valve including a second spool formed with a path, for relieving hydraulic pressure within the feedback chamber to the drain port, when output port pressure rises a predetermined relief pressure, to sharply increase the output port pressure up to the supply pressure in proportion to the current passed through the solenoid.

Proportional pressure reducing valve

In a proportional pressure reducing valve including a spool having a first end connected to a solenoid and a second end exposed to a feedback chamber, and formed with a groove for allowing a supply port to communicate with an output port when the spool is driven by the solenoid in proportional to solenoid current under balanced condition of an axial force of the solenoid and feedback pressure, the pressure reducing valve further comprises a valve for allowing the feedback chamber to communicate with a drain port to control the valve into inbalanced condition to momentarily raise output port pressure up to supply pressure, when the hydraulic output pressure within the feedback chamber rises beyond a predetermined relief pressure.

A pair of solenoids are disposed coaxially with and around a hollow cylindrical cut-off valve. The valve includes an inner non-magnetic sleeve and an outer permanent magnet sleeve. The cut-off valve slidably engages a fuel distributing plunger which injects fuel according to its axial reciprocation. The cut-off valve controls fuel injection quantity via timing of exposure of a fuel injection cut-off port in the plunger. When the pair of solenoids are energized in accordance with operating parameters of the engine, the cut-off valve is moved to a corresponding position along the plunger. A sensor senses the actual position of the cut-off valve for feedback control thereof. A pair of disc-like permanent magnets may be disposed opposite either extreme of travel of the cut-off valve in spaced relationship thereto. A pair of non-magnetic discs may be disposed in place of the pair of disc-like permanent magnets. A biasing member may be disposed between the cut-off valve and the plunger housing to prevent the cut-off valve from being attracted by the plunger housing and for preventing rotation of the cut-off valve relative to the plunger housing. The biasing member may be diaphragm, coil spring or a leaf spring.

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Yokohama, Japan

Iwane Inokuchi