Compression-ignition direct-injection combustion engine and fuel injection method for same

Patent metadata

Field	Value
Publication number	US-9885277-B2
Application number	US-201415031393-A
Country	US
Kind code	B2
Filing date	Sep 17, 2014
Priority date	Oct 25, 2013
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

The present invention is a compression-ignition direct-injection internal-combustion engine comprising at least a cylinder ( 10 ), a cylinder head ( 12 ) carrying fuel injection means ( 14 ), a piston ( 16 ) sliding in this cylinder, a combustion chamber ( 34 ) having on one side an upper face ( 44 ) of the piston comprising a projection ( 48 ) extending in the direction of the cylinder head and located at the center of a concave bowl ( 46 ). The engine comprises an injector projecting fuel in at least two fuel jet sheets with sheet injection angles (A 1 , A 2 ), a lower sheet ( 36 ) of jet axis C 1 and an upper sheet ( 38 ) of jet axis C 2 , at least two mixing zones (Z 1 , Z 2 ) of the combustion chamber. According to the invention, one of the zones comprises a toroidal volume ( 64 ) of center B into which fuel jets ( 40 ) of the lower jet are injected in such a way that axis C 1 of the lower jet is contained between center B and projection ( 48 ).

First claim

The invention claimed is:

1. A compression-ignition direct-injection internal-combustion engine comprising at least one cylinder, a cylinder head carrying fuel injection means, a piston sliding in the at least one cylinder, a combustion chamber defined on one side by an upper face of the piston comprising a projection extending in a direction of the at least one cylinder head and arranged at a center of a concave bowl, the fuel injection means projecting fuel in at least two fuel jet sheets at different sheet angles defined relative to a center axis of a cylinder, a lower sheet of a first jet axis and an upper sheet of a second jet axis, at least two mixing zones of the combustion chamber, wherein one of the zones comprises a toroidal volume having a center into which fuel jets of the lower sheet are injected so that axis of the lower sheet jets is contained between the center and the projection; and wherein
the bowl comprises a toroidal volume of radius R 1 and R 2 , a bowl bottom diameter FD, a bowl opening diameter BD, a neck diameter GD, an upper injection diameter ID 1 , a developed length of a diametral section 2*Cb of the bowl, a projection height H and a bowl height L, wherein the dimensions of the bowl meet at least one condition that ratio BD/L is less than 6; ratio FD/BD is less than 1; ratio 2*Cb/BD is less than 2; ratio GD/BD ranges between 0.7 and 1; ratio H/L is greater than 50%; ratio R 2 /R 1 is less than 1; ratio ID 1 /GD is greater than 1; and ID 1 is less than (GD+(2*Cb−GD)*⅔).

2. An internal-combustion engine as claimed in claim 1 , wherein the fuel jet sheets are located axially above one another.

3. An internal-combustion engine as claimed in claim 2 , wherein sheet angle of one of the sheets is not greater than 130° and sheet angle of the other sheet is at least 130°.

4. An internal-combustion engine as claimed in claim 1 , wherein the fuel injection means comprises at least two injectors which project fuel in a fuel jet sheet at different sheet angles.

5. An internal-combustion engine as claimed in claim 2 , wherein the fuel injection means comprises at least two injectors which project fuel in a fuel jet sheet at different sheet angles.

6. An internal-combustion engine as claimed in claim 5 , wherein sheet angle of one of the sheets is not greater than 130° and sheet angle of the other sheet is at least 130°.

7. An internal-combustion engine as claimed in claim 4 , wherein sheet angle of one of the sheets is not greater than 130° and sheet angle of the other sheet is at least 130°.

8. An internal-combustion engine as claimed in claim 1 , wherein sheet angle of one of the sheets is not greater than 130° and sheet angle of the other sheet is at least 130°.

9. An internal combustion engine as claimed in claim 1 , wherein the ratio BD/L is less than 4, the ratio H/L is greater than 60% and ratio R 1 /R 2 is less than 0.6.

10. An internal-combustion engine as claimed in claim 1 , wherein the bowl comprises an angle of inclination a 3 for an inclined flank of projection, an angle of inclination a 4 formed by a principal axis of fuel jets of the lower sheet injected into a torus by impacting the torus at a point and by a tangent impact point, an angle of inclination a 5 considered at a tangent of an outer rounded surface with lateral wall, and wherein:
a 3 is equal to a 1 ;
a 4 is greater than 80°;
a 5 ranges between 0° and 90°;
a 6 ranges between 15° and 75°; and
a 1 is an angle between the center axis and the first fuel jet axis.

11. An internal combustion engine as claimed in claim 10 , wherein a 5 ranges between 30° and 40°.

12. A method of injection for a compression-ignition direct-injection internal-combustion engine including at least one cylinder, a cylinder head carrying fuel injection means, a piston sliding in the at least one cylinder, a combustion chamber defined on one side by an upper face of the piston comprising a projection extending in a direction of the cylinder head and disposed at a center of a concave bowl, with the bowl comprising a toroidal volume of radius R 1 and R 2 , a bowl bottom diameter FD, a bowl opening diameter BD, a neck diameter GD, an upper injection diameter ID 1 , a developed length of a diametral section 2*Cb of the bowl, a projection height H and a bowl height L, wherein the dimensions of the bowl meet at least one condition that of ratio BD/L is less than 6; ratio FD/BD is less than 1; ratio 2*Cb/BD is less than 2; ratio GD/BD ranges between 0.7 and 1; ratio H/L is greater than 50%; ratio R 2 /R 1 is less than 1; ratio ID 1 /GD is greater than 1; and ID 1 is less than (GD+(2*Cb−GD)*⅔), comprising,
injecting the fuel in at least two fuel jet sheets having different sheet angles a 1 and a 2 which are measured respectively between an axis of a cylinder and a jet axis C 1 and a jet axis C 2 , a lower sheet having the jet axis C 1 and an upper sheet having the jet axis C 2 , wherein for a position D of piston considered between a bottom of the bowl and an origin of the fuel jets of the upper sheet, a D is equal to L 4 +ID 1 /tangent a 2 , L 4 is a height between the bowl bottom and point of impact of the fuel jets of the upper sheet, ID 1 is the upper injection diameter considered between impact points and a 2 is a half angle at a top of the upper sheet; and
injecting the fuel of the lower sheet into a zone comprising a toroidal volume having a center B so that axis C 1 of the fuel jets of the sheets is contained between the center B and the projection.

13. A method in accordance with claim 12 comprising:
project fuel in the fuel sheets wherein one of the sheet angles is no greater than 130° and another of the sheet angles is at least 130°.

14. A method in accordance with claim 13 , wherein a 5 ranges between 30° and 40°.

15. A method in accordance with claim 12 , wherein the bowl comprises an angle of inclination a 3 for an inclined flank of projection, an angle of inclination a 4 formed by jet axis C 1 of fuel jets of the lower sheet injected into a torus impacts the torus at an impact point and by a tangent to the impact point, an angle of inclination a 5 is considered at a tangent of an outer rounded surface with lateral wall, wherein:
a 3 is substantially equal to a 1 ;
a 4 is greater than 80°;
a 5 ranges between 0° and 90°; and
a 6 ranges between 15° and 75°.

Assignees

• Ifp Energies Now
• Airbus Helicopters

Inventors

• Martinez Lionel
• Richard Stephane
• Laget Olivier

Classifications

• F02M61/1813

  Discharge orifices having different orientations with respect to valve member direction of movement, e.g. orientations being such that fuel jets emerging from discharge orifices collide with each other · CPC title

• F02B1/12

  with compression ignition (with fuel-air charge ignited by compression ignition of an additional fuel F02B7/00) · CPC title

• F02B23/0693

  the combustion space consisting of step-wise widened multiple zones of different depth · CPC title

• F02B23/0669

  having multiple fuel spray jets per injector nozzle · CPC title

• F02B23/0672

  Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis (the surrounding wall being exactly vertical F02B23/0696) · CPC title