In-cylinder direct injection spark-ignition internal combustion engine

• US 6,705,274 B2
• Filed: 06/07/2002
• Issued: 03/16/2004
• Est. Priority Date: 06/26/2001
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kubo, Masaaki
• Primary Examiner(s): Wolfe, Willis R.
• Assistant Examiner(s): Hoang, Johnny H.
• Application Number:
  US10/163,422
• Publication Number:
  US 20020195079A1
• Time in Patent Office: 648 Days
• Field of Search: 123/292, 123/295-305, 738/613.2, 738/613.3, 239/533.11, 239/533.12, 239/490, 239/492, 239/493
• US Class Current: 123/295
• CPC Class Codes: F02B 17/005 having direct injection in the combustion chamber
• CPC Class Codes: F02B 2075/125 Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
• CPC Class Codes: F02B 23/101 the injector being placed on or close to the cylinder centre axis, e.g. with mixture formation using spray guided concepts
• CPC Class Codes: F02F 2001/245 the valve stems being orientated at an angle with the cylinder axis
• CPC Class Codes: F02M 51/0603 using piezoelectric or magnetostrictive operating means
• CPC Class Codes: F02M 61/162 Means to impart a whirling motion to fuel upstream or near discharging orifices
• CPC Class Codes: F02M 61/1806 characterised by the arrangement of discharge orifices, e.g. orientation or size
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

In a direct injection spark-ignition engine with a swirl fuel injector, an orifice nozzle tip has an inclined surface that is formed on the lower end face of the orifice nozzle tip and inclined by a predetermined inclination angle with respect to a reference plane normal to an orifice axis. The predetermined inclination angle is based on both an in-cylinder pressure dependent spray angle during the stratified-charge late fuel injection on the compression stroke and an in-cylinder pressure dependent spray angle during the homogeneous-charge early fuel injection on the intake stroke. The nozzle hole is formed within the inclined surface of the predetermined inclination angle.

Claims

1. An in-cylinder direct injection spark-ignition internal combustion engine capable of switching between a homogeneous combustion mode in which homogeneous-charge early fuel injection is executed on an intake stroke and a stratified combustion mode in which stratified-charge late fuel injection is executed on a compression stroke, comprising:

a fuel injector having an orifice nozzle tip in which a nozzle hole is formed to inject fuel through the nozzle hole directly into a combustion chamber;

a spark plug that provides a discharging gap in the combustion chamber; and

a swirl-generating device that gives rotational momentum to the fuel injected into the nozzle hole,

the orifice nozzle tip having an inclined surface that is formed on an end face of the orifice nozzle tip and inclined by a predetermined inclination angle with respect to a reference plane normal to an orifice axis of the nozzle hole, and

the nozzle hole being formed within the inclined surface.

2. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 1, wherein:

the fuel injector is laid out so that the inclined surface is directed toward the spark plug.

3. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 1, wherein:

the predetermined inclination angle of the inclined surface is set so that a spray angle of fuel spray, which is produced during the stratified-charge late fuel injection on the compression stroke, is greater than or equal to a spray angle of fuel spray, which is produced during the homogeneous-charge early fuel injection on the intake stroke.

4. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 1, wherein:

the fuel injector is laid out so that an outline of fuel spray produced during the stratified-charge late fuel injection on the compression stroke approaches the discharging gap of the spark plug.

5. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 1, wherein:

the predetermined inclination angle is set so that an outline of fuel spray produced during the stratified-charge late fuel injection on the compression stroke approaches the discharging gap of the spark plug with a predetermined delay time substantially corresponding to a distance between the nozzle hole and the discharging gap.

6. An in-cylinder direct injection spark-ignition internal combustion engine capable of switching between a homogeneous combustion mode in which homogeneous-charge early fuel injection is executed on an intake stroke and a stratified combustion mode in which stratified-charge late fuel injection is executed on a compression stroke, comprising:

a fuel injector having an orifice nozzle tip in which a nozzle hole is formed to inject fuel through the nozzle hole directly into a combustion chamber;

a spark plug that provides a discharging gap in the combustion chamber; and

a swirl-generating device that gives rotational momentum to the fuel injected into the nozzle hole,

the orifice nozzle tip having an inclined surface that is formed on an end face of the orifice nozzle tip and inclined by a predetermined inclination angle with respect to a reference plane normal to an orifice axis of the nozzle hole, and

the nozzle hole being formed within the inclined surface, wherein;

the predetermined inclination angle is dimensioned to be greater than or equal to 10 degrees.

7. An in-cylinder direct injection spark-ignition internal combustion engine capable of switching between a homogeneous combustion mode in which homogeneous-charge early fuel injection is executed on an intake stroke and a stratified combustion mode in which stratified-charge late fuel injection is executed on a compression stroke, comprising:

a fuel injector having an orifice nozzle tip in which a nozzle hole is formed to inject fuel through the nozzle hole directly into a combustion chamber;

a spark plug that provides a discharging gap in the combustion chamber; and

a swirl-generating device that gives rotational momentum to the fuel injected into the nozzle hole,

the orifice nozzle tip having an inclined surface that is formed on an end face of the orifice nozzle tip and inclined by a predetermined inclination angle with respect to a reference plane normal to an orifice axis of the nozzle hole, the predetermined inclination angle being based on both an in-cylinder pressure dependent spray characteristic during the stratified-charge late fuel injection on the compression stroke and an in-cylinder pressure dependent spray characteristic during the homogeneous-charge early fuel injection on the intake stroke, and

the nozzle hole being formed within the inclined surface.

8. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 7, wherein:

the fuel injector is laid out so that the inclined surface is directed toward the spark plug.

9. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 7, wherein:

the predetermined inclination angle of the inclined surface is set so that a spray angle of fuel spray, which is produced during the stratified-charge late fuel injection on the compression stroke, is greater than or equal to a spray angle of fuel spray, which is produced during the homogeneous-charge early fuel injection on the intake stroke.

10. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 7, wherein:

the fuel injector is laid out so that an outline of fuel spray produced during the stratified-charge late fuel injection on the compression stroke approaches the discharging gap of the spark plug.

11. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 7, wherein:

the predetermined inclination angle is set so that an outline of fuel spray produced during the stratified-charge late fuel injection on the compression stroke approaches the discharging gap of the spark plug with a predetermined delay time substantially corresponding to a distance between the nozzle hole and the discharging gap.

12. An in-cylinder direct injection spark-ignition internal combustion engine capable of switching between a homogeneous combustion mode in which homogeneous-charge early fuel injection is executed on an intake stroke and a stratified combustion mode in which stratified-charge late fuel injection is executed on a compression stroke, comprising:

a fuel injector having an orifice nozzle tip in which a nozzle hole is formed to inject fuel through the nozzle hole directly into a combustion chamber;

a spark plug that provides a discharging gap in the combustion chamber; and

a swirl-generating device that gives rotational momentum to the fuel injected into the nozzle hole,

the orifice nozzle tip having an inclined surface that is formed on an end face of the orifice nozzle tip and inclined by a predetermined inclination angle with respect to a reference plane normal to an orifice axis of the nozzle hole, the predetermined inclination angle being based on both an in-cylinder pressure dependent spray characteristic during the stratified-charge late fuel injection on the compression stroke and an in-cylinder pressure dependent spray characteristic during the homogeneous-charge early fuel injection on the intake stroke, and

the nozzle hole being formed within the inclined surface, wherein;

the predetermined inclination angle is dimensioned to be greater than or equal to 10 degrees.

13. An in-cylinder direct injection spark-ignition internal combustion engine capable of switching between a homogeneous combustion mode in which homogeneous-charge early fuel injection is executed on an intake stroke and a stratified combustion mode in which stratified-charge late fuel injection is executed on a compression stroke, comprising:

a fuel injector having an orifice nozzle tip in which a nozzle hole is formed to inject fuel through the nozzle hole directly into a combustion chamber;

a spark plug that provides a discharging gap in the combustion chamber; and

a swirl flow component generating means for giving rotational momentum to the fuel injected into the nozzle hole,

the orifice nozzle tip having an inclined surface formed on an end face of the orifice nozzle tip and inclined by a predetermined inclination angle with respect to a reference plane normal to an orifice axis of the nozzle hole for creating an inclined substantially hollow cone fuel spray, the predetermined inclination angle of the inclined surface being based on both an in-cylinder pressure dependent spray characteristic during the stratified-charge late fuel injection on the compression stroke and an in-cylinder pressure dependent spray characteristic during the homogeneous-charge early fuel injection on the intake stroke, and

the nozzle hole being formed within the inclined surface.

14. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 13, wherein:

the inclined surface comprises a flat surface that is sloped toward the spark plug.

15. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 13, wherein:

the inclined surface comprises a concave curved surface that is concave down.

16. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 13, wherein:

the inclined surface comprises a convex curved surface that is convex down.

17. An in-cylinder direct injection spark-ignition internal combustion engine capable of switching between a homogeneous combustion mode in which homogeneous-charge early fuel injection is executed on an intake stroke and a stratified combustion mode in which stratified-charge late fuel injection is executed on a compression stroke, comprising:

a fuel injector having an orifice nozzle tip in which a nozzle hole is formed to inject fuel through the nozzle hole directly into a combustion chamber;

a spark plug that provides a discharging gap in the combustion chamber; and

a swirl flow component generating means for giving rotational momentum to the fuel injected into the nozzle hole,

the orifice nozzle tip having an inclined surface formed on an end face of the orifice nozzle tip and inclined by a predetermined inclination angle with respect to a reference plane normal to an orifice axis of the nozzle hole for creating an inclined substantially hollow cone fuel spray, the predetermined inclination angle of the inclined surface being based on both an in-cylinder pressure dependent spray characteristic during the stratified-charge late fuel injection on the compression stroke and an in-cylinder pressure dependent spray characteristic during the homogeneous-charge early fuel injection on the intake stroke, and

the nozzle hole being formed within the inclined surface, wherein said engine further comprises;

a needle valve movable in a direction of the orifice axis to open and close the nozzle hole by axial movement of the needle valve,

wherein the swirl flow component generating means comprises a swirler chip having a plurality of tangential fuel flow passageways each extending in a tangential direction of the needle valve to create a circumferential fuel flow velocity component in a circumferential direction of the nozzle hole.

18. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 17, wherein:

the orifice axis is inclined by a predetermined inclination angle with respect to an axis of the needle valve, the predetermined inclination angle of the orifice axis being based on both the in-cylinder pressure dependent spray characteristic during the stratified-charge late fuel injection on the compression stroke and the in-cylinder pressure dependent spray characteristic during the homogeneous-charge early fuel injection on the intake stroke.

19. An in-cylinder direct injection spark-ignition internal combustion engine capable of switching between a homogeneous combustion mode in which homogeneous-charge early fuel injection is executed on an intake stroke and a stratified combustion mode in which stratified-charge late fuel injection is executed on a compression stroke, comprising:

a fuel injector having an orifice nozzle tip in which a nozzle hole is formed to inject fuel through the nozzle hole directly into a combustion chamber;

a spark plug that provides a discharging gap in the combustion chamber; and

a swirl-generating device that gives rotational momentum to the fuel injected into the nozzle hole,

wherein the nozzle hole has a predetermined nonzero average inclination angle with respect to a reference plane normal to an orifice axis of the nozzle hole.

20. The in-cylinder direct injection spark-ignition internal combustion engine as claimed in claim 19, wherein the predetermined average inclination angle is at least 10 degrees.