EP0453416B1 - Motor-vehicle internal combustion engine with differentially opened valves - Google Patents

Motor-vehicle internal combustion engine with differentially opened valves Download PDF

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Publication number
EP0453416B1
EP0453416B1 EP91830144A EP91830144A EP0453416B1 EP 0453416 B1 EP0453416 B1 EP 0453416B1 EP 91830144 A EP91830144 A EP 91830144A EP 91830144 A EP91830144 A EP 91830144A EP 0453416 B1 EP0453416 B1 EP 0453416B1
Authority
EP
European Patent Office
Prior art keywords
valves
internal combustion
combustion engine
motor
vehicle internal
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
EP91830144A
Other languages
German (de)
French (fr)
Other versions
EP0453416A1 (en
Inventor
Giorgio Bertero
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.)
Fiat Auto SpA
Original Assignee
Fiat Auto SpA
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 Fiat Auto SpA filed Critical Fiat Auto SpA
Publication of EP0453416A1 publication Critical patent/EP0453416A1/en
Application granted granted Critical
Publication of EP0453416B1 publication Critical patent/EP0453416B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
    • 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
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/42—Shape or arrangement of intake or exhaust channels in cylinder heads
    • F02F1/4214—Shape or arrangement of intake or exhaust channels in cylinder heads specially adapted for four or more valves per cylinder
    • 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
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F2001/244—Arrangement of valve stems in cylinder heads
    • F02F2001/247—Arrangement of valve stems in cylinder heads the valve stems being orientated in parallel with the cylinder axis

Definitions

  • the present invention relates to motor-vehicle internal combustion engines having at least one cylinder with an associated pair of intake and/or exhaust valves and a camshaft for controlling the opening and closing of both valves of the pair by means of two respective pivoted rocker fingers.
  • the object of the present invention is to avoid this disadvantage by providing an internal combustion engine of the type defined above in which the differentiated opening of the two valves is achieved without the need to provide two separate cams or two rockers with different profiles.
  • this object is achieved by virtue of the fact the rockers of the two valves are identical to each other and have respective centres of pivoting disposed on opposite sides of the camshaft, and in that the two rockers are operated by a single common cam.
  • the common cam operates the two valves differently due to the different interactions of the two rockers resulting exclusively from their opposed positioning. This effect is achieved with a number of essential components (a single cam and two identical rockers) which eliminates almost all structural complication in the engine.
  • part of the head of a multi-cylinder internal combustion engine for motor vehicles is generally indicated 1 and is provided in correspondence with each cylinder with a pair of intake (or exhaust) valves 2, 3 controlled by a distributor shaft 4 supported for rotation by the head 1.
  • Each valve 2, 3 has a rod 5, 6 the top of which is operatively associated with a respective rocker 7, 8.
  • the two rods 5, 6 also have respective associated biasing springs 9, 10, in conventional manner.
  • the two rockers 7, 8 are of the finger type and are formed with respective cam-follower surfaces 11, 12 which, according to the invention, cooperate with a single, common cam 13 of the distributor shaft 4.
  • This cam 13 has an axial extent such as to ensure contact between its own outer profile and the two cam-follower surfaces 11, 12.
  • the two rocker fingers 7, 8 are pivotably supported at respective ends opposite the rods 2, 3 by means of articulation heads 14, 15 supported at the tops of respective hydraulic tappets 16, 17 of known type with automatic play recovery.
  • the two rocker fingers 7, 8 are identical to each other and are disposed symmetrically, in mutually opposite positions with respect to the distributor shaft 4: the fulcra 14, 15 with the respective hydraulic tappets 16, 17 are in fact situated on opposite sides of the shaft 4.
  • the interaction between the cam 13 and the two cam-follower surfaces 11, 12 of the two rockers 7, 8 effects a differentiated opening/closing cycle for the two valves 2, 3, in use.
  • This cycle is shown schematically in the graph of Figure 3 as a function of time and of the angular position of the cam 13 during one complete revolution.
  • the curve A represents the opening/closing graph of the valve 2 while the curve B represents the valve 3: as can be seen, the opening/closing cycle of the second is delayed relative to that of the first so that, when the valve 2 starts its reclosure travel, the valve 3 has yet to reach its fully-open position.
  • the condition in which both valves are completely closed, is, however, reached at the same instant.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)

Description

  • The present invention relates to motor-vehicle internal combustion engines having at least one cylinder with an associated pair of intake and/or exhaust valves and a camshaft for controlling the opening and closing of both valves of the pair by means of two respective pivoted rocker fingers.
  • In this type of engine, in order to obtain optimum performance, it is desirable to effect the sequential cycle of the opening/closing of the two valves in a differentiated manner so that the full opening of one of the two valves follows the full opening of the other valve after a predetermined delay.
  • Conventionally this is achieved, as illustrated in the European patent publication EP-A-319956, with the aid of two separate cams with different profiles for controlling the two valves and/or with different shaped cam-follower profiles for the rockers of one valve and the other.
  • Both solutions are structurally complex in that they require the manufacture of different components.
  • The object of the present invention is to avoid this disadvantage by providing an internal combustion engine of the type defined above in which the differentiated opening of the two valves is achieved without the need to provide two separate cams or two rockers with different profiles.
  • According to the invention, this object is achieved by virtue of the fact the rockers of the two valves are identical to each other and have respective centres of pivoting disposed on opposite sides of the camshaft, and in that the two rockers are operated by a single common cam.
  • By virtue of this arrangement, the common cam operates the two valves differently due to the different interactions of the two rockers resulting exclusively from their opposed positioning. This effect is achieved with a number of essential components (a single cam and two identical rockers) which eliminates almost all structural complication in the engine.
  • The invention will now be described in detail with reference to the appended drawings, provided purely by way of non-limiting example, in which:
    • Figure 1 is a partially-sectioned, schematic, vertical view of a motor-vehicle internal combustion engine according to the invention,
    • Figure 2 is a perspective view of the distributor group of the engine shown in Figure 1, and
    • Figure 3 is a graph showing the opening/closing of the two valves of the unit shown in Figure 2.
  • With reference to the drawings, part of the head of a multi-cylinder internal combustion engine for motor vehicles is generally indicated 1 and is provided in correspondence with each cylinder with a pair of intake (or exhaust) valves 2, 3 controlled by a distributor shaft 4 supported for rotation by the head 1. Each valve 2, 3 has a rod 5, 6 the top of which is operatively associated with a respective rocker 7, 8. The two rods 5, 6 also have respective associated biasing springs 9, 10, in conventional manner.
  • The two rockers 7, 8 are of the finger type and are formed with respective cam- follower surfaces 11, 12 which, according to the invention, cooperate with a single, common cam 13 of the distributor shaft 4. This cam 13 has an axial extent such as to ensure contact between its own outer profile and the two cam- follower surfaces 11, 12.
  • The two rocker fingers 7, 8 are pivotably supported at respective ends opposite the rods 2, 3 by means of articulation heads 14, 15 supported at the tops of respective hydraulic tappets 16, 17 of known type with automatic play recovery.
  • In accordance with the invention, the two rocker fingers 7, 8 are identical to each other and are disposed symmetrically, in mutually opposite positions with respect to the distributor shaft 4: the fulcra 14, 15 with the respective hydraulic tappets 16, 17 are in fact situated on opposite sides of the shaft 4.
  • Thanks to this arrangement, the interaction between the cam 13 and the two cam- follower surfaces 11, 12 of the two rockers 7, 8 effects a differentiated opening/closing cycle for the two valves 2, 3, in use. This cycle is shown schematically in the graph of Figure 3 as a function of time and of the angular position of the cam 13 during one complete revolution. The curve A represents the opening/closing graph of the valve 2 while the curve B represents the valve 3: as can be seen, the opening/closing cycle of the second is delayed relative to that of the first so that, when the valve 2 starts its reclosure travel, the valve 3 has yet to reach its fully-open position. The condition in which both valves are completely closed, is, however, reached at the same instant.

Claims (1)

  1. A motor vehicle internal combustion engine having at least one cylinder with an associated pair of intake and/or exhaust valves (2,3) and a camshaft (4) for controlling the opening and closing of both valves (2,3) of the pair by means of two respective pivoted rocker fingers (7,8), and in which means are provided for effecting the differentiated opening of the two valves, characterised in that the rocker FINGERS (7, 8) of the two valves (2, 3) are identical to each other and have respective fulcra (14, 15) disposed on opposite sides of the camshaft (4), and in that the two rockers (7, 8) are operated by a single common cam (13).
EP91830144A 1990-04-20 1991-04-16 Motor-vehicle internal combustion engine with differentially opened valves Expired - Lifetime EP0453416B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT6729990 1990-04-20
IT67299A IT1240204B (en) 1990-04-20 1990-04-20 INTERNAL COMBUSTION ENGINE FOR VEHICLES WITH DIFFERENTIATED OPENING VALVES

Publications (2)

Publication Number Publication Date
EP0453416A1 EP0453416A1 (en) 1991-10-23
EP0453416B1 true EP0453416B1 (en) 1993-03-31

Family

ID=11301258

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91830144A Expired - Lifetime EP0453416B1 (en) 1990-04-20 1991-04-16 Motor-vehicle internal combustion engine with differentially opened valves

Country Status (5)

Country Link
EP (1) EP0453416B1 (en)
BR (1) BR9101698A (en)
DE (1) DE69100054T2 (en)
ES (1) ES2040149T3 (en)
IT (1) IT1240204B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06173619A (en) * 1992-12-08 1994-06-21 Yamaha Motor Co Ltd 4-cycle engine valve mechanism
JPH084505A (en) * 1994-06-17 1996-01-09 Yamaha Motor Co Ltd Engine valve gear
JP3546278B2 (en) * 1996-04-19 2004-07-21 トヨタ自動車株式会社 Valve train for internal combustion engine

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1751401A1 (en) * 1968-05-24 1971-02-18 Klaue Hermann Four-valve cylinder head for internal combustion engines
FR2562162B1 (en) * 1984-03-27 1988-05-27 Peugeot CYLINDER HEAD FOR THREE-VALVE INTERNAL COMBUSTION ENGINE
US4964375A (en) * 1987-12-08 1990-10-23 Nissan Motor Co., Ltd. Valve operating mechanism

Also Published As

Publication number Publication date
DE69100054T2 (en) 1993-07-08
IT1240204B (en) 1993-11-27
EP0453416A1 (en) 1991-10-23
ES2040149T3 (en) 1993-10-01
IT9067299A0 (en) 1990-04-20
BR9101698A (en) 1991-12-10
IT9067299A1 (en) 1991-10-20
DE69100054D1 (en) 1993-05-06

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