WO2009090508A2

WO2009090508A2 - Plunger pair

Info

Publication number: WO2009090508A2
Application number: PCT/IB2008/053574
Authority: WO
Inventors: Olexiy Nick Klishyn; Olexandr Georgiyovych Kesariys'kyy
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-01-14
Filing date: 2008-09-04
Publication date: 2009-07-23
Anticipated expiration: 2010-07-14
Also published as: WO2009090508A4; WO2009090508A3

Abstract

Object of invention: a plunger pair, preferably for a high-pressure pump, comprising a plunger and a cylinder. Field of invention: high-pressure fuel pumps, preferably in the field of engine-building, including, but not limited to, those configured to pump steam and a biofuel with oxygen additives. The essence of the invention: a device which comprises a plunger and a cylinder the contacting surfaces of which are coated with a layer of an ultradispersed fluoroplastic, wherein the external surface of the plunger comprises recesses that have a standardized depth and are of a certain configuration. Technical result: An embodied manufacturing process which provides reduction in kinematical friction losses, increase in tightness between the plunger and the liner, reduction in plunger pair part wear, and the use of the pump for new fuels.

Description

PLUNGER PAIR

Technical Field

[1] The present invention relates to the field of engine-building, and more particularly, to high-pressure fuel pumps used, for instance, in diesel engines. Background Art

[2] It is well known in the art that the level of pressure in plunger pumps is between 30.0

MPa and 120 MPa while the ring gap between the plunger and the cylinder (liner, housing) is from one to several microns long. A high pressure and small gaps between moving parts of the plunger pair create preconditions for the wear of contacting surfaces, the increase in kinematical losses, and pressure reduction when the plunger pair is operated.

[3] The device wherein a plunger pair is embodied with using a fluoroplastic cup that contacts with the plunger surface is well known from the state of the art (see, for example, Russian Pat. No. 2068111 Cl RU. - F02M59/44 entitled "A PLUNGER PAIR OF A HIGH-PRESSURE FUEL PUMP", issued to M. G. Sandomirskiy, V. G. Dyachenko, patent application No. 94023691/06, filed on June 22, 1994, published on October 10, 1996). The above mentioned device partially solves the problem of sealing between the plunger and the liner but the employment of such a design results in the occurrence of parasitic volumes. Moreover, this solution fails to overcome the problem of plunger wear at the area of its contact with the guide surface of the liner which negatively influences on a plunger pair useful life.

[4] There are also devices wherein the plunger is made with fluoroplastic rings serving as seals (see, for example, Russian Pat. No. 99101379 A RU.- F04B47/12 entitled "A SELF-SEALING PLUNGER", issued to G. KH. Ayrapetov, patent application No. 99101379/06, filed on January 21, 1999, published on October 27, 2000, and Russian Pat. No. 2265752 C2 RU. - F04B53/02 entitled "A COMPOSITE PLUNGER OF A POSITIVE DISPLACEMENT PUMP" issued to S. I. Kudriashov, E. M Khasanov, S. I. Gorbunov, et al. - patent application No. 2004101023/06, filed on January 19, 2004, published on December 10, 2005). Said plunger designs provide a high level of sealing and reduce kinematical losses when moving in the cylinder (liner). However, the employment of such a solution in small-sized designs with precision gaps of several microns, can't provide a high level of plunger pair reliability, because small geometrical dimensions of sealing elements do not provide parts with enough strength under conditions of high-frequency, alternate and high- amplitude load. Disclosure of Invention Technical Solution

[5] The technical result of the present invention is therefore to provide reduction in kinematical friction losses, increase in tightness between the plunger and the liner, reduction in plunger pair part wear, and the use of the pump for new fuels.

[6] The technical result is attained according to present invention in a way, that an external surface of a plunger and an internal surface of a cylinder of a plunger pair are coated with a layer of an ultradispersed fluoroplastic; recesses filled with the ultra- dispersed fluoroplastic are made on the plunger surface. The recesses are made in the form of circular grooves with sloping edges, and the depth of the said recesses is 0.1 and 2 times as much as the standardized gap between the plunger and the cylinder.

[7] Coating of the contacting surfaces of the plunger pair with the ultradispersed fluoroplastic makes it possible to create (unlike the application of a fluoroplastic film) a fluoroplastic layer which, having the depth between a fraction of a micron and several microns, has an extremely firm bond with the surface due to the penetration of fluoroplastic nanoparticles into the relief of the parts. The application of the fluoroplastic layer requires no change in geometric dimensions of the parts and their limits because the ultradispersed fluoroplastic may be applied as a layer the depth of which does not exceed a fraction of a micron and does not affect the constructively predetermined limits. The application of the fluoroplastic layer results in a significant reduction in friction, increase in compression, and reduction in the wear of parts. Furthermore, a high chemical inertness provides an anticorrosion protection of precision surfaces against the influence of aggressive components of fuel this enabling the plunger pair in accordance with the present invention to be used in pumps which pump a biofuel and other fuels with oxygen additives.

[8] The providing of recesses filled with the ultradispersed fluoroplastic on the plunger surface enables, due to low-temperature yield properties of fluoroplastic, the predetermined depth of the surface layer of ultradispersed fluoroplastic to be maintained.

[9] The providing of recesses filled with the ultradispersed fluoroplastic on the plunger surface and which are made in the form of circular grooves with sloping edges enables such a mode of ultradispersed fluoroplastic particle transfer during a reciprocating motion of the plunger which allows the fluoroplastic to be used as a solid lubricant. A portion of the ultradispersed fluoroplastic particles circulates between the recesses and constantly renews the anticorrosion layer and antifriction layer on the contacting surfaces of the plunger pair.

[10] Setting the depth of the recesses is 0.1 and 2 times as much as the standardized gap between the plunger and the cylinder enables the layer of the ultradispersed fluoroplastic in the recesses to be optimized to ensure an anticorrosion and antifriction protection of the plunger pair parts and reduction the probability of a brittle failure of the ultradispersed fluoroplastic, that fills the recesses. Industrial Applicability

[11] The device in accordance with the present invention may be easily produced using the state-of-the-art technologies. For example, there are a lot of methods of producing an ultradispersed fluoroplastic with the size of its particles not exceeding 100 nanometers by the means of thermogas dynamic destruction, electron-beam dispersion, etc. Recesses on precision surfaces can be made by rolling or electrochemical treatment. Such technologies are a routine practice and do not result in any significant change in the cost of the device.

[12] Preferably, the device in accordance with the present invention may be applied in high-pressure plunger pumps for pumping fuels. Especially preferable is its use for fuels, which contain active oxygen additives such as, for example, biofuels. Such a fuel, unlike oil processing products, has great prospects of use and high environment- friendly characteristics of an engine. Increase in the useful life and reliability of high- pressure pumps pumping such a fuel may be achieved by using the technical solution in accordance with the present invention.

[13] The device in accordance with the present invention may also be used in high- pressure plunger pumps for pumping steam.

[14] The technical solution in accordance with the present invention may also be employed for quick routine repairs of high-pressure plunger pumps for pumping traditional fuels. The application of a ultradispersed fluoroplastic layer to plunger and liner worn surfaces would enable the initial geometry of these parts to be restored and, accordingly, the predetermined compression to be renewed and the useful life of engine fuel units to be extended.

[15] The authors have performed a number of experimental investigations, which have proved efficiency of a practical use of the technical solution in accordance with the present invention. The materials of these investigations may be presented to the Examiner if so requested thereby.

Claims

[1] L A plunger pair consisting of a plunger and a cylinder, characterized in that the external surface of the plunger and the internal surface of the cylinder are coated with a layer of an ultradispersed fluoroplastic. [2] 2. The plunger pair of Claim 1, characterized in that the recesses filled with the ultradispersed fluoroplastic are provided at the plunger surface. [3] 3. The plunger pair of Claim 2, characterized in that the recesses have a shape of circular grooves with sloping edges. [4] 4. The plunger pair of Claims 1 and 2, characterized in that a depth of the recesses is between 0.1 and 2 times as much as the standardized gap between the plunger and the cylinder.