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 
• • 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 
  • F02F3/28—Other pistons with specially-shaped head
• • 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 
  • F02F3/0076—Pistons  the inside of the pistons being provided with ribs or fins

Definitions

• the present invention relates generally to pistons for internal combustion engines.
• a piston having a piston body which extends along a longitudinal central axis.
• the piston body has a crown portion with a combustion wall and a pair of pin bosses which depend from the crown portion.
• the crown portion includes at least two ribs formed integrally therewith with each rib depending from the combustion wall. One of the ribs depends (or extends) lower along the longitudinal central axis than the other of the ribs.
• the ribs enhance the strength of the upper crown to resist bending about a pin bore axis without substantially increasing the mass of the piston. Additionally, the ribs act as a heat sink to extract heat away from the combustion wall and cool the piston.
• the ribs extend between the pin bosses and bow outwardly from the pin bore axis.
• the length of the ribs is increased without substantially increasing the mass of the piston.
• a piston including a piston body extending along a longitudinal central axis and having a crown portion with a combustion wall and a pair of pin bosses depending generally from the crown portion.
• the combustion wall includes at least one combustion bowl formed therein, and the crown portion includes at least one rib formed integrally therewith and depending from the combustion bowl directly beneath the at least one combustion bowl.
• the at least one rib enhances the strength of the upper crown at the location of the combustion bowl, which often is located at the center of the combustion in the cylinder bore.
• Figure 1 is a perspective view of a piston constructed in accordance with one aspect of the present invention.
• Figure 2 is a side view of the piston of Figure 1 ;
• Figure 3 is a bottom view of the piston of Figure 1 ;
• Figure 4 is a cross-sectional view taken generally along the line 4-4 of
• Figure 5 is a cross-sectional view taken generally along the line 5-5 of
• a piston 20 constructed in accordance with one presently preferred aspect of the invention is generally shown in Figures 1-5.
• the piston 20 of the exemplary embodiment is constructed of one integral piece which is preferably cast to a near-final shape then machined to its final dimensions.
• the piston 20 could alternately be of multiple pieces which could be shaped and joined to one another through any desirable processes.
• the piston 20 is preferably formed of an aluminum alloy but could alternately be of steel or any desirable metal or alloy thereof.
• the exemplary one-piece piston 20 has a piston body 22 extending along a longitudinal central axis Aj and having an upper crown portion 24, a pair of pin bosses 26 and a pair of skirt portions 28.
• the upper crown portion 24 includes a combustion wall 30 and a plurality of ring grooves 32 spaced axially from the combustion wall 30 for receiving piston 20 rings (not shown).
• the pin bosses 26 extend downwardly along the longitudinal central axis Ai from the upper crown portion 24.
• Each of the pin bosses 26 has a pin bore 34, and the pin bores 34 are aligned with one another along a pin bore axis A2 (shown in Figure 3) for receiving a wrist pin (not shown) to interconnect the piston 20 with the small end of a connecting rod (not shown).
• the skirt portions 28 are disposed diametrically opposite of one another with each skirt portion 28 extending between and interconnecting the pin bosses 26.
• the piston body 22 reciprocates along the longitudinal central axis Ai within a cylinder bore (not shown) of an engine block (not shown) to rotate a crankshaft (not shown) via the connecting rod (not shown).
• the combustion wall 30 includes a generally planar portion, a raised portion (pop-up) and a combustion bowl 36 formed therein.
• the combustion bowl 36 is configured asymmetrically relative to the longitudinal central axis A], i.e. the center of the combustion bowl 36 is not disposed along the longitudinal central axis Ai. However, it should be appreciated that the combustion bowl 36 could alternately be disposed symmetrically about the central axis Ai.
• combustion of the fuel and gasses in the cylinder bore is often focused around the combustion bowl 36, thereby generating increased pressures and heat at this location.
• the combustion bowl 36 is typically the highest stressed area on the crown portion 24
• the exemplary piston 20 has an undercrown support structure for strengthening the upper crown portion 24 to resist these forces.
• the piston 20 includes a pair of ribs 38, 40 spaced diametrically from one another and extending generally between the pin bosses 26 to reinforce the upper crown portion 24, thereby enhancing the upper crown portion's 24 resistance to bending about the pin bore axis A2 when the combustion wall 30 is exposed to the increased pressures and temperatures of an engine with direct injection, a turbo-charger and/or a super-charger. This enhanced resistance to bending is achieved without a substantial increase in the mass of the piston 20.
• each of the ribs 38, 40 is generally bowed, or arc-shaped, to increase the area of support beneath the combustion wall 30, thereby further enhancing the upper crown's resistance to bending about the pin bore axis ⁇ 2 ⁇
• the arc-shape of the ribs 38, 40 also allows the ribs 38, 40 to generally smoothly mate, or be interconnected with, with the opposite pin bosses 26, thereby avoiding the creation of unwanted stresses at the intersection of these elements.
• each of the ribs 38, 40 depends from and is integrally formed with the upper crown portion 24.
• the ribs 38, 40 may be formed "as cast" with the upper crown with little to no additional cost.
• the ribs 38, 40 could be formed into the upper crown through any suitable process.
• the ribs 38, 40 also may function as a heat sink to draw heat away from the combustion wall 30 of the upper crown to cool the combustion wall 30. This heat-sink effect further enhances the piston's 20 resistance to the increased combustion temperatures.
• the ribs could alternately be linearly-shaped or could even arc inwardly, depending on the needs of the particular piston design.
• the combustion wall 30 of the exemplary piston 20 is formed with a generally uniform thickness in both the location of the combustion bowl 36 and in the areas surrounding the combustion bowl 36.
• One of the ribs 38, 40 hereinafter referred to as a "first rib 38”
• first rib 38 depends from the combustion wall 30 directly beneath the combustion bowl 36.
• second rib 40 depends from the combustion wall 30 diametrically opposite of the first rib 38 and is spaced from the combustion bowl 36.
• the first rib 38 (which is directly beneath the combustion bowl 36) is recessed relative to the second rib 40, i.e. the first rib 38 extends lower than the second rib 40.
• the underside of the combustion wall 30 has an asymmetrical appearance as viewed in cross-section.
• the first rib 38 arcs not only outwardly away from the pin bore axis A 2 but also vertically towards the pin bosses 26 of the piston body 22.
• the skirt portions 28 extend generally concentrically with the ribs 38, 40.
• the skirt portions 28 have the same or approximately the same radius of curvature as the ribs 38, 40.
• the skirt portions 28 do not have to be concentric with the ribs 38, 40.

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)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=46551872

Family Applications (1)

Country Status (5)

Cited By (1)

Citations (3)

Family Cites Families (14)

• 2012
  • 2012-06-28 EP EP12738286.9A patent/EP2726724B1/en not_active Not-in-force
  • 2012-06-28 CN CN201711058426.2A patent/CN107842437B/zh not_active Expired - Fee Related
  • 2012-06-28 CN CN201280037963.8A patent/CN103748345A/zh active Pending
  • 2012-06-28 JP JP2014519000A patent/JP6226866B2/ja not_active Expired - Fee Related
  • 2012-06-28 WO PCT/US2012/044564 patent/WO2013003546A1/en active Application Filing
  • 2012-06-28 KR KR1020137034245A patent/KR20140032455A/ko not_active Application Discontinuation
• 2017
  • 2017-02-16 JP JP2017026983A patent/JP6396521B2/ja not_active Expired - Fee Related

Patent Citations (3)

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