US3377925A - Internal combustion engines - Google Patents

Internal combustion engines Download PDF

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Publication number
US3377925A
US3377925A US511834A US51183465A US3377925A US 3377925 A US3377925 A US 3377925A US 511834 A US511834 A US 511834A US 51183465 A US51183465 A US 51183465A US 3377925 A US3377925 A US 3377925A
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US
United States
Prior art keywords
engine
wall
walls
crankcase
thickness
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.)
Expired - Lifetime
Application number
US511834A
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English (en)
Inventor
Austen Alan Ewart Walter
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.)
CAV Ltd
Original Assignee
CAV Ltd
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
Application filed by CAV Ltd filed Critical CAV Ltd
Application granted granted Critical
Publication of US3377925A publication Critical patent/US3377925A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • F02F7/00—Casings, e.g. crankcases or frames
    • F02F7/0085—Materials for constructing engines or their parts
    • 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
    • F02F7/00—Casings, e.g. crankcases or frames
    • F02F7/0065—Shape of casings for other machine parts and purposes, e.g. utilisation purposes, safety
    • F02F7/008—Sound insulation
    • 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

Definitions

  • a variation in thickness along anyone wall should not be greater than 13:1 and a variation in thickness between any two walls should not be greater than 1.5 :1.
  • This invention relates to internal combustion'engines of the reciprocating piston type and in which the crankcase comprises a pair of end walls which respectively form supports for bearings for the crankshaft of the engine and a pair of side walls interconnecting and formed integrally with the end walls.
  • the object of the invention is to provide an engine of this kind in which the emission of noise from the walls is reduced as compared with known engines.
  • an engine of the kind specified is characterized by the fact that the walls are not locally thickened and are of approximately equal thickness such that the dynamic magnification factor of each wall is not more than 3.
  • FIGURE 1 is a part-sectional side elevation of one example of an engine in accordance with the invention.
  • FIGURE 2 is a section on the line 2--2 of FIGURE 1 with parts removed for the sake of clarity.
  • an engine crankcase having a pair of end walls incorporating apertures accommodating bearing 10a, and a pair of side walls 11 interconnecting the end walls 10.
  • a crankshaft 12 upon which are mounted connecting rods 13 which are connected to pistons (not shown) accommodated within cylinder liners 14 mounted in the upper portion of the crankcase.
  • a cylinder head 15 secured to the upper face of the crankcase is a cylinder head 15 in which are defined combustion chambers and in which is mounted the valve gear of the engine.
  • the crankshaft 12 is also supported intermediate its length by an intermediate wall 16.
  • the end walls, side Walls and intermediate wall extend well below the axis of rotation of the crankshaft but this is not essential to the present invention.
  • the end walls, side walls and the corner portions are of equal thickness and no strengthening ribs are provided as is the case with known crankcases.
  • the thickness of the walls is required to be such that the loads imposed upon them when the engine is running can be safely carried by the walls.
  • accessories such for instance as a fuel pump have to be mounted on the engine in a position to be driven by the crankshaft and for this purpose a mounting boss or bosses must be provided.
  • a boss is indicated at 17 in FIGURE 1.
  • the walls of the crankcase are locally thickened at their junctions with adjacent walls and along their free edges, and usually incorporate strengthening ribs.
  • the thickened portions constitute the equivalent of a frame interconnected by thinner panels.
  • the thickened portions constituting the frame carry the majority of the stress imposed on the crankcase when the engine is operative and the relatively thin portions which are equivalent to panels magnify the vibration imparted to the frame,
  • the dynamic magnification factor when applied to panels of the type under consideration has reference to a ratio of the amplitude of vibration at the middle of the panel or wall as compared with the amplitude of vibration at the periphery of the wall.
  • the periphery of the wall is subjected to the vibrations developed by the reciprocating components of the engine and a relatively small amplitude of vibration at the periphery of a panel or wall results in a much larger amplitude of vibration at the middle of the Wall.
  • the dynamic magnification factor is a ratio of the two amplitudes and has not units.
  • crankcase wall Since the thickness of the major portion of the crankcase wall will, by the present invention, be thicker than is normal, it is convenient to construct the crankcase from a relatively light material such, for example, as aluminium or magnesium.
  • crankcase/cylinder block casting of either a conventional engine or an engine of the kind described, before being built-up, is substantially undamped, so that any part may have a dynamic magnification factor of 20 or more.
  • the main structure of either type of construction becomes heavily damped i.e. it may have a dynamic magnification factor of less than 3.
  • the vibration levels of the load-carrying part of the structure are comparable in the two engines, the levels in the centre regions of the side walls are reduced relatively in the engine of the specified structure by some 10 db and the noise emitted is also reduced by some 10 db.
  • a frameless crankcase for an engine including interconnected end .and side walls constituting the outer surface of the crankcase and said walls having a dynamic magnification factor of not more than 3.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)
US511834A 1964-12-08 1965-12-06 Internal combustion engines Expired - Lifetime US3377925A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB49965/64A GB1124508A (en) 1964-12-08 1964-12-08 Internal combustion engines

Publications (1)

Publication Number Publication Date
US3377925A true US3377925A (en) 1968-04-16

Family

ID=10454148

Family Applications (1)

Application Number Title Priority Date Filing Date
US511834A Expired - Lifetime US3377925A (en) 1964-12-08 1965-12-06 Internal combustion engines

Country Status (5)

Country Link
US (1) US3377925A (de)
CH (1) CH440837A (de)
FR (1) FR1456379A (de)
GB (1) GB1124508A (de)
SE (1) SE307038B (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58207519A (ja) * 1982-05-27 1983-12-03 Nissan Motor Co Ltd 内燃機関の主軸受構造

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1286621A (en) * 1917-01-16 1918-12-03 William J Henley Jr Double thermostatic control of explosive mixtures.
US1287386A (en) * 1917-06-21 1918-12-10 Int Motor Co Sheet-metal internal-combustion engine.
GB249974A (en) * 1925-02-07 1926-04-08 William Beardmore Improvements in or relating to casings for internal combustion engines

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1286621A (en) * 1917-01-16 1918-12-03 William J Henley Jr Double thermostatic control of explosive mixtures.
US1287386A (en) * 1917-06-21 1918-12-10 Int Motor Co Sheet-metal internal-combustion engine.
GB249974A (en) * 1925-02-07 1926-04-08 William Beardmore Improvements in or relating to casings for internal combustion engines

Also Published As

Publication number Publication date
CH440837A (de) 1967-07-31
SE307038B (de) 1968-12-16
GB1124508A (en) 1968-08-21
FR1456379A (fr) 1966-10-21

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