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
  • F02F7/0021—Construction
  • F02F7/0031—Construction kit principle (modular engines)
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62K—CYCLES; CYCLE FRAMES; CYCLE STEERING DEVICES; RIDER-OPERATED TERMINAL CONTROLS SPECIALLY ADAPTED FOR CYCLES; CYCLE AXLE SUSPENSIONS; CYCLE SIDECARS, FORECARS, OR THE LIKE
  • B62K7/00—Freight- or passenger-carrying cycles
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
  • F01B1/00—Reciprocating-piston machines or engines characterised by number or relative disposition of cylinders or by being built-up from separate cylinder-crankcase elements
  • F01B1/12—Separate cylinder-crankcase elements coupled together to form a unit
• • 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
  • F02B61/00—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing
  • F02B61/02—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing for driving cycles
• • 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
  • F02B75/00—Other engines
  • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
  • F02B75/18—Multi-cylinder engines
  • F02B75/22—Multi-cylinder engines with cylinders in V, fan, or star arrangement
• • 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
  • F02F7/00—Casings, e.g. crankcases
• • 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
  • F02B75/00—Other engines
  • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
  • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
  • F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
• • 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
  • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
  • F02B2275/18—DOHC [Double overhead camshaft]
• • 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
  • F02F2001/245—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis

Definitions

• the present invention refers to a family of power units that are essentially constituted by internal- combustion engines and related transmission and/or change gears for two-wheeled and three- wheeled vehicles.
• multi-cylinder engines which may also be of a different architecture (in-line or V-shaped cylinder arrangement, etc.) and have higher power ratings.
• the power units considered as a whole the definition of which is closely connected to the different types of vehicle where they are intended to be used.
• the present invention tackles the above-cited problems and aims at taking into a different account the needs and the requirements of both the manufacturers and the users, thence also of the various power units used on two-wheeled and three-wheeled vehicles.
• motor-scooters which are enjoying an increasing and favourable acceptance thanks also to the fact that they are very easy to drive since they are provided with power units that comprise a continuously-variable transmission.
• Their manufacturers have to take into due account several requirements, such as the possibility of adopting engines having different power and piston-displacement ratings, the adoption of wheels of a different diameter (eg. 13-in. and 16-in. wheels) and the need for an adequate surface to be anyway provided for the feet of the driver to rest upon.
• the present invention consists of a family of power units comprising engines having a medium-to-low piston-displacement volume (not in excess of 250 cu.cm, indicatively), which are essentially intended for use in two-wheeled and three-wheeled vehicles, which are characterized by a highly standardized and modular construction as recited and defined in the appended claims.
• FIG. 1 is a side overall view of a power unit for use on a motor-scooter, which comprises a four-stroke single-cylinder engine according to the present invention in combination with a continuously-variable transmission, the latter being only shown schematically;
• FIG. 2 is a partially cutaway overall view of the same power unit, which also shows a number of construction details of the above mentioned continuously-variable transmission;
• FIG. 3 is a view of the head of the cylinder of the same engine, starting from the plane whose intersection with the sheet of the drawing is the straight line A-A indicated in Figure 1 ;
• - Figure 4 is a view of the same head along the section line X-X of Figure 3;
• FIG. 5 is a partially cross-sectional view along the line B-B of Figure 2 of the rear portion of the continuously-variable transmission;
• - Figure 6 is a partially cross-sectional view along the line C-C of Figure 2 of the rear portion of the same continuously-variable transmission
• - Figure 7 is a side overall view of a power unit for use on a motor-cycle, which comprises the same single-cylinder engine as the one shown in the preceding Figures, and a different multi-speed, i.e. discretely-variable transmission gear, the latter being only shown schematically owing to its being of a per se known traditional construction;
• FIG. 8 is a side overall view of a power unit for use on a motor-cycle, which comprises a four-stroke engine with two cylinders provided in a V-arrangement combined to a different multi- speed discretely-variable transmission gear, the latter being only shown schematically owing to the same reason as cited in Figure 7.
• a continuously-variable transmission which is indicated generally at 300, is comprised in the power unit of Figures 1 and 2 and will be described further on with reference to greater details illustrated in Figures 5 and 6, while a first kind of a multi-speed discretely-variable transmission, which is indicated generally at 400, is comprised in the power unit illustrated in Figure 7 while a second kind of multi-speed discretely-variable transmission, which is generally indicated at 500, is comprised in the power unit illustrated in Figure 8.
• the present invention also covers power units that comprise the single-cylinder engine 100 in conjunction with a discretely-variable transmission 500 or the two-cylinder engine 200 in conjunction with the continuously-variable transmission 300 or, again, the two-cylinder engine 200 in conjunction with the discretely-variable transmission 400.
• the engine 100 comprises a block 1 10 and a single cylinder 112 with the associated piston 114 driven by the crankshaft 116 via the connecting- rod 118.
• the continuously-variable transmission 300 which will be described in greater detail further on with special reference to Figures 5 and 6, is enclosed in a casing 301 equipped with a removable cover 302, and comprises : a driving pulley 304 on the front side; a driven pulley 310; a gearbox 320; the axle 330 of the driving wheel on the rear side; a driving belt 308 linking the pulleys 304 and 310 with each other.
• Shown in Figures 1 and 2 is also the ring 330, the axis of which is indicated at P2, for the attachment of the rear shock-absorbing strut (not shown) to the power unit when the latter is used on a motor-scooter.
• crankshaft 116 of the engine 100 is firmly joined to a rectilinear shaft 120, the axis of rotation of which is indicated at Po in Figure 2, for the support of the driving pulley 304 of the continuously-variable transmission 300.
• the shaft 120 may be a direct prolongation of the crankshaft 116, outside of the block 110, so that mentioned axes Z and Po may also be coincident.
• the axis X of the cylinder 112 forms a quite small angle, typically in the order of 10 to 20°, with the plane that contains the axis Po of the driving pulley 304 and the axis Pi of the driven pulley 310.
• the straight line that is formed by the intersection of this plane with the plane of the drawing.
• the engine 100 comprises a head 130, in which there are to be found some of the main features of the present invention, and a removable cover 140 for closing from the top the same head 130.
• a head 130 in which there are to be found some of the main features of the present invention, and a removable cover 140 for closing from the top the same head 130.
• Four stud bolts are used to fasten the head 130 to the cylinder 112, as this is best shown in
• FIG 3 by the corresponding holes 131 , 142, 143 and 144. Further bolts, some of which are shown in Figure 2 where they are indicated at 151 , 152, 153, are in turn used to fasten the cover 140 on to the head 130.
• the head 130 (in which there are provided, in a per se well-known manner, the induction manifolds 132 and the exhaust manifolds 136, along with the flowpaths of lubrication oil and cooling water, as well as the seat 139 - shown in Figure 3 - of the spark plug, not shown) forms the housing for the whole timing system of the engine 100.
• this timing system is of the DOHC type and comprises, among other things : a first shaft (not shown, for sake of simplicity) for the actuation of two suction valves 131 by means of corresponding cams 133 and springs 134, and a second shaft (also not shown) for the actuation of two exhaust valves 135 by means of corresponding cams 137 and springs 138, the second axis of the said shafts being parallel to one another - see Figures 3 and 4.
• the dimensional characteristics of the head and of the timing system are the same not only for the whole family of power units of the invention, i.e. for the entire range of piston-displacement volumes and horsepower ratings, but also for both the single-cylinder engine 100 described hitherto and the two-cylinder engine 200 that will be described further on with special reference to Figure 8.
• the values of the angle of inclination C of the suction valves 131 and the angle of inclination D of the exhaust valves 135 are preferably the same throughout the family of power units when they are selected from within variation ranges that are delimited by following minimum and maximum values:
• the single-cylinder engine that is part of the power unit comprising the multi-speed discretely-variable transmission 400 illustrated in Figure 7 and the two-cylinder engine 200 that is part of the power unit comprising the multi-speed discretely-variable transmission 500 illustrated in Figure 8 have the same characteristics as regards their linear and angular dimensions.
• the continuously-variable transmission 300 - attached to the rear suspension of the vehicle through the fixation ring 330 at a position defined by the axis P 2 which lies in a rear position with respect to the axis Pi of the driven pulley 310, as this is best shown in Figure 1 - features some characteristics that are best illustrated in Figures 5 and 6.
• the driven pulley 310 of the transmission 300 can be the driven pulley 310 of the transmission 300, which is enclosed between the casing 301 and a removable cover 302 and consists of a first idle part 312 and a second part 314 that rotates jointly with the shaft 316, along with the driving belt 308.
• the shaft 316 carries also the driving gearwheel (not shown) of the gearbox 320 and extends all along the afore cited axis Pi.
• the shaft 316 of the driven pulley 310 is provided with three supports, i.e. one support more than in traditional continuously-variable transmissions.
• the third support 318 is constituted by a bearing that is situated at the free end portion 317 of the shaft 316 (i.e. on the opposite side with respect to the gearbox associated to the same shaft).
• the third support 318 is kept in position by the cover 302 by means of a bush 319 that - according to another feature of the invention - is made of a plastic material or, alternatively, by a spring ring.
• continuously-variable transmission 300 features the following advantages as compared with a traditional construction, which is typically disclosed in US-A-4 475 893 and US- A-4 567 958 :
• the overall construction of the continuously-variable transmission 300 is simplified thanks to a reduction in the parts list, since the cover 302 is used here not only as a means for closing the casing 301 , but also to perform a structural task;
• the elastic deformability of the bush 319 also contributes to dampening the vibrations of the whole power unit.
• a further feature of the present invention relates to the cooling of the driving pulley 304 of the continuously-variable transmission 300, which rotatably drives the belt 308.
• the driving pulley 304 comprises a so-called moving disk 306, which is slidable on the shaft 120, and a so-called fixed ring
• the casing 301 is provided with a preferably removable cover 305, which is provided with a large aperture 325 exactly in front of the fixed disk 307, whereas the outer face 309 of the fixed disk 307, i.e. the face thereof which lies on the opposite side with respect to the engine of the power unit, is configured as a centrifugal fan.
• the casing 301 is closed in such a manner to create in its interior a flowpath 303 for the cooling air, which completely surrounds the pulley 304 - as indicated by the arrows Fi to F ⁇ appearing in Figure 6 - and extends both in front of and behind the belt 308.
• the latter is in this way stressed to a lower extent and has a longer durability, with a clear advantage in terms of overall reliability of the power unit.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Arrangement Of Transmissions (AREA)
• Arrangement Or Mounting Of Propulsion Units For Vehicles (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=31898459

Family Applications (1)

Country Status (4)

Families Citing this family (3)

Family Cites Families (7)

• 2002
  • 2002-08-20 EP EP02807731A patent/EP1546537A1/de not_active Withdrawn
  • 2002-08-20 AU AU2002334399A patent/AU2002334399A1/en not_active Abandoned
  • 2002-08-20 CN CN02829470.XA patent/CN1656308A/zh active Pending
  • 2002-08-20 WO PCT/IT2002/000544 patent/WO2004018861A1/en not_active Ceased

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events