EP0393142A1 - Ensemble a piston et son element de piston a rapport de compression predetermine entre la hauteur et le diametre. - Google Patents

Ensemble a piston et son element de piston a rapport de compression predetermine entre la hauteur et le diametre.

Info

Publication number
EP0393142A1
EP0393142A1 EP89901632A EP89901632A EP0393142A1 EP 0393142 A1 EP0393142 A1 EP 0393142A1 EP 89901632 A EP89901632 A EP 89901632A EP 89901632 A EP89901632 A EP 89901632A EP 0393142 A1 EP0393142 A1 EP 0393142A1
Authority
EP
European Patent Office
Prior art keywords
piston
piston assembly
top surface
wrist pin
skirt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP89901632A
Other languages
German (de)
English (en)
Other versions
EP0393142B1 (fr
Inventor
Benny Ballheimer
Stephen G Shoup
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar Inc
Original Assignee
Caterpillar Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=22993400&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0393142(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Caterpillar Inc filed Critical Caterpillar Inc
Publication of EP0393142A1 publication Critical patent/EP0393142A1/fr
Application granted granted Critical
Publication of EP0393142B1 publication Critical patent/EP0393142B1/fr
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/0015—Multi-part pistons
    • F02F3/0069—Multi-part pistons the crown and skirt being interconnected by the gudgeon pin
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F2200/00—Manufacturing
    • F02F2200/04—Forging of engine parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/02—Light metals
    • F05C2201/021—Aluminium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/04—Heavy metals
    • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/04—Heavy metals
    • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
    • F05C2201/0448—Steel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2251/00—Material properties
    • F05C2251/04—Thermal properties
    • F05C2251/042—Expansivity

Definitions

  • This invention relates generally to a compact engine piston assembly for a high output internal combustion engine, and more particularly to a piston assembly including a steel piston member capable of resisting relatively high combustion chamber pressures and temperatures.
  • a high output engine piston assembly and piston member therefor which is capable of continuous and efficient operation at combustion chamber pressures above about 13,790 kPa (2,000 psi), and preferably in the region of about 15,170 kPa (2,200 psi).
  • the piston member should be relatively easy to manufacture by having a configuration substantially devoid of complex shapes to allow the manufacturing thereof.
  • the upper portion of the piston member should preferably be as smooth and symmetrical as possible to avoid stress risers and/or differential thermal distortion thereof.
  • the compressive height "CH" of the piston member should preferably be as small as structurally practical for maximizing compactness.
  • the present invention is directed to overcoming one or more of the problems as set forth above.
  • a steel piston member for reciprocatable movement in a high combustion chamber pressure engine comprises an upper portion of substantially cylindrical shape and having a preestablished maximum diameter "D", a lower portion, a compression height "CH”, and a preestablished ratio of the compression height "CH” to the preestablished maximum diameter "D".
  • the upper portion has a peripheral top surface, a tubular wall depending from the top surface, an annular outwardly facing wall surface and an annular cooling recess.
  • the lower portion includes a pair of depending pin bosses blendingly associated with the outwardly facing wall surfaces. The pin bosses individually define a wrist pin receiving bore aligned on a common axis.
  • the compression height "CH” is defined by the elevational distance between the common axis and the top surface.
  • the preestablished ratio of the compression height "CH” to the preselected maximum diameter"D" is within the range of from 60% to 45%.
  • an articulated piston assembly for reciprocatable movement in a high combustion chamber pressure engine comprises a steel piston member having an upper portion having a preestablished maximum diameter "D” and a lower portion, a compression height "CH", a preestablished ratio of the compression height "CH” to the preselected maximum diameter "D” being within the range of from 60% to 45%, a skirt and a wrist pin.
  • the upper portion has a peripheral top surface, a tubular wall depending from the top surface, an annular outwardly facing wall surface and an annular cooling recess.
  • the lower portion includes a pair of depending pin bosses blendingly associated with the outwardly facing wall surfaces. The pin bosses individually define a wrist pin receiving bore aligned on a common axis.
  • the skirt is of generally or slightly elliptical shape.
  • the skirt is slidably positioned on the lower portion and has a pair of wrist pin receiving bores aligned with the common axis.
  • the wrist pin is slidably disposed in the pair of wrist pin receiving bores.
  • an articulated piston assembly is adapted for use in a high combustion chamber pressure engine having a combustion chamber pressure in excess of about 13,790 kPa (2000 psi) comprises a steel piston member having an upper portion having a preestablished maximum diameter "D" and a lower portion, a compression height "CH", a preestablished ratio of the compression height "CH” to the preselected maximum diameter "D” being within the range of from 60% to 45%, a skirt and a wrist pin.
  • the upper portion has a peripheral top surface, a tubular wall depending from the top surface, an annular outwardly facing wall surface and an annular cooling recess.
  • the lower portion includes a pair of depending pin bosses blendingly associated with the outwardly facing wall surfaces.
  • the pin bosses individually define a wrist pin receiving bore aligned on a common axis.
  • the skirt is of a generally or slightly elliptical shape and also has a pair of wrist pin receiving bores aligned with the common axis.
  • the wrist pin is slidably disposed in the two pairs of wrist pin receiving bores.
  • an articulated piston assembly having a relative low compression height to diameter ratio adapted for use in a high combustion chamber pressure engine having a combustion chamber pressure of about 13,790 kPa (2000 psi) comprises a steel piston member having an upper portion and a lower portion which are integrally formed of steel, a skirt of slightly elliptical shape having a top surface in non-contacting relationship to the upper portion is slidably positioned about the lower portion and has a wrist pin slidably connecting the skirt to the piston member.
  • the present invention provides structural members which represent a simple, inexpensive, and lightweight solution to resist the increasing combustion pressures and combustion temperatures of todays and future engines.
  • FIG. 1 is a diagrammatic, fragmentary, transverse vertical sectional view of an engine piston assembly constructed in accordance with the present invention
  • Fig. 2 is a longitudinal vertical sectional view of a portion of the piston assembly illustrated in Fig. 1 as taken along the line II-II thereof;
  • Fig. 3 is an enlarged fragmentary portion of the top peripheral region of the piston member shown in Fig. 1 and 2 to better show details of construction thereof;
  • Fig. 4 is a top view of the piston member shown in Fig. 2 as taken along line IV-IV thereof;
  • Fig. 5 is a top view solely of the piston skirt shown in Fig. 2 as taken along line V-V thereof;
  • Fig. 6 an enlarged fragmentary cross sectional view of the top peripheral region of the piston member shown in Figs. 1 and 2 which shows the flow lines of a simple forged piston member with only a portion of the cooling recess forged;
  • Fig. 7 is an enlarged fragmentary cross sectional view of the top peripheral region of the piston member shown in Figs. 1 and 2 which shows the flow lines of a forged piston member with a deeply forged cooling recess. Best Mode for Carrvin ⁇ Out the Invention
  • an internal combustion engine 10 of the ulti-cylinder type includes a bottom block 12, a top block or spacer portion 14, and a cylinder head 16 rigidly secured together in the usual way by a plurality of fasteners or bolts 18 which pass through the head and block and are screwthreadably received in the bottom block.
  • a mid-supported cylinder liner 48 has an upper portion 52 positioned in the top block portion 14 and is provided with coolant flow therearound.
  • the engine 10 could be of any conventional design.
  • the engine 10 further includes a cooling oil directing nozzle 74 as is shown in the lower right portion of Fig. 1.
  • This nozzle is rigidly secured to the bottom block 12 and is operationally associated with a conventional source of pressurized oil, not shown, to supply oil or the like to an articulated piston assembly 76.
  • the piston assembly 76 of the engine 10 includes an upper steel piston member 78 and a lower aluminum piston skirt 80 which are rockably mounted on a common wrist pin or gudgeon pin 82 having a longitudinally oriented central axis 84.
  • the wrist pin is also of steel material and has an external cylindrical surface 86, and a cylindrical bore 88 therethrough for weight reduction purposes.
  • a conventional connecting rod 90 of a tepee configuration has an upper eye end 92, and a steel-backed bronze sleeve bearing 94 therein is operationally connected to, and driven by, the wrist pin.
  • the steel piston member 78 has an upper portion 96 of substantially cylindrical shape and a preselected maximum diameter "D" as is illustrated in Fig. 2.
  • the upper portion 96 has a peripheral top surface 98 that is flat, or is located on a plane perpendicular to the central axis 66, and a crown surface 100 that in the instant example is a fully machined surface of revolution about the central axis 66.
  • the crown surface has a centrally located apex portion 102 elevationally disposed below the top surface, a peripheral or radially outer land portion 104 that is substantially cylindrical and an annular trough 106 that smoothly blends with the apex and outer land portions.
  • the piston member 78 further includes a tubular wall 108 that depends from the outer edge of the top surface 98 and defines in serially depending order fully around the periphery thereof a top land 110, a top ring groove 112 having a keystone or wedge-like shape in cross section, an upper intermediate land 114, an intermediate ring groove 116 of rectangular cross section, a lower intermediate land 118, a bottom ring groove 120 of rectangular cross section, and a bottom land 122 that is terminated by a lower end surface
  • annular radially inwardly facing wall surface 126 is also delineated by the wall 108 and extends upwardly from the end surface 124.
  • the upper portion 96 is additionally defined by an annular radially outwardly facing wall surface 128 and a downwardly facing transition portion 130 that is blendingly associated with the wall surfaces 126 and 128 to collectively define an annular cooling recess 132 of a precisely defined cross sectional shape.
  • the wall surface 128 is defined by an upper fully conical portion 134 having an inclination angle "A" with respect to the central axis 66 of approximately 12 degrees as is shown in Fig. 3, and a fully cylindrical portion 136 below it.
  • the wall surface 126 is fully conical and has an inclination angle "B" of approximately 1.7 degrees.
  • the annular cooling recess 132 could be of any configuration to be forged such as the shallow recess shown in Fig. 6 or as an alternative the deep recess as shown in Fig. 7.
  • the grain flow obtained with a forging are shown by use of phantom lines.
  • the steel piston member 78 further includes a lower portion 158 including a pair of depending pin bosses 160 blendingly associated with the outwardly facing wall surface 128 of the upper portion 96, and blendingly associated also with a downwardly facing concave pocket 162 defined by the upper portion.
  • the concave pocket is spaced substantially uniformly away from the apex portion 102 of the crown surface 100 so as to define a crown 164 of generally uniform thickness "C" of about 4 or 5mm as is shown in Figs. 2 and 3.
  • these figures also illustrate and define a relatively thin and substantially conically oriented web 166 of a minimum thickness "W" of about 4 to 7mm between the trough 106 and juxtaposed land portion 104 of the crown surface 100, and the outwardly facing wall surface 128.
  • Each of the pin bosses 160 has a bore 168 therethrough which are adapted to individually receive a steel-backed bronze bearing sleeve 170 therein. These bearing sleeves are axially aligned to receive the wrist pin 82 pivotally therein.
  • the piston skirt 80 has a top peripheral surface 172 in close non-contacting relationship with the lower end surface 124 of the upper portion 96 of the piston member 78 with a fully annular, upwardly facing oil trough 174 defined therein. It further has a slightly elliptical external surface 176 therearound which depends from the top surface.
  • the skirt 80 further has a maximum diameter 177 and a minimum diameter 177a.
  • a pair of aligned wrist pin receiving bores 178 are formed through the piston skirt and are axially aligned with the minimum diameter 177a, and each of the bores has a snap ring receiving groove 180 therein.
  • the piston skirt is thus pivotally mounted on the wrist pin 82 which is slidably insertably positioned in both bores. Excessive movement of the wrist pin is prevented along the axis 84 by a pair of split retaining rings 182 individually disposed in the grooves 180.
  • a pair of axially oriented bosses 184 are defined within the skirt 80 so that a corresponding pair of lubrication passages 186 can be provided fully axially therethrough.
  • the lubrication passages are positioned diagonally opposite each other so that the skirt can be mounted on the wrist pin 82 in either of the two possible positions, and so at least one of them will be axially aligned with the oil jet nozzle 74.
  • the skirt is also provided with diagonally opposite, semi-cylindrical recesses 188 which open downwardly at the bottom of the skirt to provide clearance from the nozzle when the skirt is reciprocated to its lowest elevational position.
  • the steel piston member 78 in this application is used with an articulated piston assembly 76.
  • the articulated piston assembly is used in a high combustion chamber pressure engine 10 having a combustion chamber pressure of 15,170 kPa (2200 psi) .
  • the articulated piston assembly 76 allows the power output to be increased and reduces the engine package size.
  • the articulated piston assembly 76 is used with an engine 10 having a mid-supported cylinder liner 48 and a two piece cylinder block 12,14 construction. Liquid cooling is positioned in only the top block 14 of the two piece block and provides excellent cooling or heat dissipation for the piston assembly.
  • the articulated piston assembly 76 reciprocates downwardly to bottom dead center whereupon the nozzle 74 directs lubricating oil into the skirt passage 186 aligned therewith.
  • the oil jet continues upwardly whereupon it makes contact with the surfaces of the cooling recess 132 of the piston member 78 and is splashed peripherally in opposite directions. A significant portion of the oil is caught by the skirt trough 174 as the piston assembly is reciprocated and further more evenly distributed around the interior of the piston member.
  • the top of the cooling recess 132 is elevationally disposed directly underneath the peripheral top surface 98 of the piston member, and within an elevational distance therefrom identified by the letter "E” of about 5mm. It has been concluded that the ratio of the distance “E” to the piston diameter “D” should be below about 0.10, and preferably should be between about 0.04 and 0.06. In one embodiment the diameter "D” was 124mm, and the distance “E” was 5.5mm which provides a ratio thereof of approximately 0.044. In the same embodiment the elevational distance "CH” between the top surface 98 and the wrist pin axis 84 was 70mm. Therefore, the ratio of "CH” to "D” was about 0.56.
  • the ratio of "CH" to "D” should be below about 0.60, and preferably should be between about 0.60 and 0.45. 5
  • the articulated piston assembly 76 is preferably manufactured in a particular way and by using certain materials.
  • the upper steel piston member 10 . 78 is preferably forged from an alloy steel which is basically 4140 modified steel.
  • the lower aluminum piston skirt 80 is likewise preferably forged from a modified aluminum which is basically SAE 321-T6 modified aluminum. 15
  • the aforementioned alloy steel is particularly adaptable to a Class II forging, and can provide an austenitic grain size 5 or finer which is highly desirable to resist the high combustion pressures associated with the high combustion chamber 0 pressure engine.
  • the grain flow primarily in the web 166, as shown in Figs. 6 and 7, and grain size allows the forces to be resisted or transmitted and provides the high strength, factor of safety and long life which is required in todays high combustion 5 chamber pressure engines.
  • the aforementioned forged aluminum alloy has a high hardness, excellent wear resistance, and a relatively low coefficient of thermal expansion.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

Les moteurs diesel actuels dotés d'ensembles à pistons en aluminium sont limités à des pressions de chambre de combustion d'approximativement 12.410 kPa (1.800 psi), tandis que les efforts de recherche ont pour objectif d'augmenter ces pressions jusqu'à une plage de 15.170 kPa (2.200 psi). Afin d'atteindre ces niveaux l'ensemble à piston (76) de l'invention comprend un élément de piston (78) en acier ayant une partie cylindrique supérieure (96) d'un diamètre ''D'' et une hauteur de compression ''CH''. Le rapport entre la hauteur de compression ''CH'' et le diamètre ''D'' étant situé dans la plage comprise entre 60 % et 45 %. Ledit élément de piston (78) est de préférence forgé puis usiné à des dimensions pouvant être commandées avec précision. De plus, l'ensemble à piston (78) est de préférence du type articulé et comprend une jupe (80) de piston en aluminium forgé, reliée à l'élément de piston (78) par l'intermédiaire d'un maneton commun (82). Les constructeurs de moteurs cherchent également à réduire la taille du moteur tout en maintenant la puissance, ainsi qu'à améliorer la consommation de carburant et à réduire les émissions. L'élément de piston (76) de l'invention constitue une solution simple et économique satisfaisant la relation entre la puissance accrue et une taille réduite. Afin de produire un ensemble de moteur de taille réduite, ledit élément de piston (78) a un rapport entre la hauteur de compression et le diamètre maximum situé dans la plage comprise entre 60 % et 45 %. Ledit élément de piston (78) est de préférence en acier forgé afin d'assurer une porosité réduite par rapport à celle des pièces coulées standard existantes.
EP89901632A 1988-10-21 1989-05-08 Ensemble a piston et son element de piston a rapport de compression predetermine entre la hauteur et le diametre Revoked EP0393142B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US26145988A 1988-10-21 1988-10-21
US261459 1988-10-21

Publications (2)

Publication Number Publication Date
EP0393142A1 true EP0393142A1 (fr) 1990-10-24
EP0393142B1 EP0393142B1 (fr) 1994-01-19

Family

ID=22993400

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89901632A Revoked EP0393142B1 (fr) 1988-10-21 1989-05-08 Ensemble a piston et son element de piston a rapport de compression predetermine entre la hauteur et le diametre

Country Status (5)

Country Link
EP (1) EP0393142B1 (fr)
JP (1) JP2656640B2 (fr)
BR (1) BR8807836A (fr)
DE (1) DE3887344T2 (fr)
WO (1) WO1990004711A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4326978A1 (de) * 1993-08-11 1995-02-16 Alcan Gmbh Kolben für Brennkraftmaschinen, insbesondere für Dieselmotoren
US6862976B2 (en) * 2001-10-23 2005-03-08 Federal-Mogul World Wide, Inc. Monobloc piston
US20110030214A1 (en) * 2009-08-05 2011-02-10 Wolfgang Rein Piston assembly multiple step forming process
CN106401784A (zh) * 2016-06-23 2017-02-15 华晨汽车集团控股有限公司 一种具有减重结构的活塞组件

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4180027A (en) * 1977-07-20 1979-12-25 Mack Trucks, Inc. Two-piece oil-cooled piston
DE3210771A1 (de) * 1982-03-24 1983-09-29 Günter 8543 Hilpoltstein Elsbett Kolbentrieb fuer hubkolben-brennkraftmaschinen, wie dieselmotoren u.a.
DE3430132A1 (de) * 1984-08-16 1986-02-27 Mahle Gmbh, 7000 Stuttgart Aluminium-tauchkolben fuer verbrennungsmotoren mit regelstreifen
DE3742616A1 (de) * 1986-12-23 1988-07-28 Mahle Gmbh Einteiliger, leichter und reibungsarmer leichtmetallkolben fuer verbrennungsmotoren

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9004711A1 *

Also Published As

Publication number Publication date
DE3887344T2 (de) 1994-05-05
WO1990004711A1 (fr) 1990-05-03
BR8807836A (pt) 1990-11-13
JPH03502719A (ja) 1991-06-20
EP0393142B1 (fr) 1994-01-19
JP2656640B2 (ja) 1997-09-24
DE3887344D1 (de) 1994-03-03

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