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High-pressure fuel pumpRelated Patent Categories: Pumps, Expansible Chamber Type, Electrically Or Magnetically Actuated DistributorHigh-pressure fuel pump description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070110603, High-pressure fuel pump. Brief Patent Description - Full Patent Description - Patent Application Claims
CLAIM OF PRIORITY [0001] The present application claims priority from Japanese application serial no. 2005-331036, filed on Nov. 16, 2005, the contents of which are hereby incorporated by references into this application. FIELD OF THE INVENTION [0002] The present invention relates to a high-pressure fuel pump for feeding high-pressure fuel to a fuel injection valve in an internal combustion engine. [0003] The present invention is particularly concerned with a high-pressure fuel pump having a relief valve device installed into a pump body, the relief valve device serving as a safety device for returning fuel to a pressurizing chamber when the pressure of discharged fuel becomes abnormally high. BACKGROUND ART [0004] In Japanese Patent Laid-Open Publication No. 2004-138062 there is described a high-pressure fuel pump having a relief valve device, the relief valve device comprising a valve seat member having a central fuel passage and a seat surface formed around the central fuel passage, a valve element serving as a relief valve for being placed against the seat surface, and a spring member for pushing the valve element against the seat surface, the relief valve device being mounted to a body of the pump in such a manner that the spring member is positioned on the pressurizing chamber side. [0005] However, in the above prior art, since the relief valve device is installed within the pressurizing chamber or within a passage leading to the pressurizing chamber, the volume of the pressurizing chamber substantially becomes large and the compression efficiency becomes lower. [0006] More particularly, it suffices for the volume of the pressurizing chamber to be about 1 to 2 CC, but since the relief valve device is installed, the volume of the pressurizing chamber or the sum of the volume of the pressurizing chamber and that of the relief valve installed portion becomes 6 to 7 CC. Consequently, assuming that the stroke of a plunger piston (hereinafter referred to simply as "plunger") within the pressurizing chamber is the same, the compression efficiency becomes lower. SUMMARY OF THE INVENTION [0007] It is an object of the present invention to provide a high-pressure fuel pump which, even if a body of the pump is provided with a relief valve device for returning fuel abnormally high in pressure from an outlet passage to a pressurizing chamber, is high in compression efficiency, i.e., high in energy efficiency, without increasing the volume of a compression chamber. [0008] The above object of the present invention can be achieved by constructing the relief valve device so that only the relief valve as a valve element can be installed on the pressurizing chamber side and the spring mechanism can be installed on the outlet passage side of the pump. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 is an entire cross sectional view of a high-pressure fuel pump according to a first embodiment of the present invention; [0010] FIG. 2 is an assembling diagram for explaining a unit of a relief valve device used in the first embodiment; [0011] FIG. 3 is an entire longitudinal sectional view of the high-pressure fuel pump of the first embodiment; [0012] FIG. 4 shows an example of a fuel supply system using the high pressure fuel supply system of the first embodiment; [0013] FIG. 5 shows pressure waveforms in various portions of the high-pressure fuel pump of the first embodiment and in a common rail; [0014] FIG. 6 is an entire cross sectional view of a high-pressure fuel pump according to a second embodiment of the present invention; [0015] FIG. 7 is a diagram for explaining a unit of a relief valve device used in the second embodiment; [0016] FIG. 8 is an entire cross sectional view of a high-pressure fuel pump according to a third embodiment of the present invention; and [0017] FIG. 9 is an entire cross sectional view of a high-pressure fuel pump according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENTS [0018] A first embodiment of the present invention will be described hereinafter with reference to FIGS. 1 to 5. Continue reading about High-pressure fuel pump... Full patent description for High-pressure fuel pump Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this High-pressure fuel pump patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like High-pressure fuel pump or other areas of interest. ### Previous Patent Application: Pump Next Patent Application: Scroll machine Industry Class: Pumps ### FreshPatents.com Support Thank you for viewing the High-pressure fuel pump patent info. 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