METHOD OF OPERATING AN INTERNAL COMBUSTION ENGINE

• US 20140000553A1
• Filed: 04/06/2013
• Published: 01/02/2014
• Est. Priority Date: 10/07/2010
• Status: Abandoned Application

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler AG (Mercedes-Benz Group AG)
• Inventors: DIELER, Torsten, HAASE, Dirk, HERWEG, Ruediger
• Application Number:
  US13/858,013
• Publication Number:
  US 20140000553A1
• Time in Patent Office: Days
• US Class Current: 123/295
• CPC Class Codes: F02B 17/005 having direct injection in the combustion chamber
• CPC Class Codes: F02D 41/006 using internal EGR control of valve overlap for internal EGR F02D13/0261; arrangements for internal EGR F02M26/01
• CPC Class Codes: F02D 41/3041 with means for triggering compression ignition, e.g. spark plug
• CPC Class Codes: F02D 41/3064 with special control during transition between modes
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An operating mode of an internal combustion engine, in particular a directly injected internal combustion engine featuring a plurality of combustion chambers, in particular for a direct-injection gasoline engine for a motor vehicle, an operating mode having at least in part low-NOx combustion (NAV) and having a plurality of partial operating modes wherein it is switched between another partial operating mode and a NAV partial operating mode, wherein in the case of said NAV partial operating mode, at an ignition point (ZZP) a largely homogeneous, lean fuel/exhaust gas/air mixture having a combustion air ratio of λ≧1 is spark ignited in the respective combustion chamber by means of an ignition device, and where a flame front combustion (FFV) initiated by the spark-ignition transitions to a controlled auto-ignition (RZV).

The operational stability of the respective partial operating mode can be improved by variation of the compression ratio ε.

Claims

1. Operating mode for an, in particular direct-injection, internal combustion engine with exhaust gas recirculation, in particular for a direct injection gasoline engine, comprising:

wherein a RZV partial operating mode is implemented in a region of the engine characteristics map having low to medium speed and/or low to medium load, said RZV partial operating mode having a lean fuel/exhaust gas/air mixture that is ignited by compression ignition and combusts by controlled auto-ignition (RZV),

wherein the region of the engine characteristics map with compression ignition is bordered at higher load by another region of the engine characteristics map in which low-NOx combustion (NAV) is performed,

wherein at an ignition point (ZZP) a homogeneous, lean fuel/exhaust gas/air mixture with combustion air ratio λ

≧

1 in a given combustion chamber of the internal combustion engine is spark ignited by means of an ignition device,

wherein a flame front combustion (FFV) initiated by the spark ignition transitions to controlled auto-ignition (RZV),

wherein it is switched between at least one other partial operating mode and a NAV partial operating mode wherein a change in the compression ratio ε

is undertaken when switching from on partial operating mode to another partial operating mode.

2. Operating mode according to claim 1, wherein the respective partial operating mode is selected depending on the engine load and/or the engine speed.

3. Operating mode according to claim 1 wherein at least one switch selected from the following set is performed:

a switch between the RZV partial operating mode having pure controlled auto-ignition (RZV) and the NAV partial operating mode,

a switch between a spark ignited, stratified DES partial operating mode (stratified direct injection) and the NAV partial operating mode,

a switch between the RZV partial operating mode and an HOS partial operating mode (stratified homogeneous mode),

a switch between the NAV partial operating mode and the HOS partial operating mode,

a switch between the DES partial operating mode and the HOS partial operating mode.

4. Operating mode according to claim 1, wherein when changing to the NAV partial operating mode, the compression ratio ε

is lowered.

5. Operating mode according to claim 1, wherein the NAV partial operating mode is implemented with a compression ratio ε

between 10 and 13 and/or the HCCI partial operating mode is implemented with a compression ratio ε

between 10 and 15 and the DES partial operating mode is implemented with a compression ratio ε

between 10 and 15.

6. Operating mode according to claim 1, wherein a switch between the RZV partial operating mode and the NAV partial operating mode is undertaken at an engine speed of between 5% and 70% of the maximum engine speed and/or at an engine load of between 5% and 30% of the maximum motor load and/or a switch between the DES partial operating mode and the NAV partial operating mode is undertaken at an engine speed of between 5% and 70% of the maximum engine speed and/or at an engine load of between 5% and 30% of the maximum motor load.

7. Operating mode according to claim 1, wherein at higher engine loads, switching occurs between the NAV partial operating mode and a spark ignited, SI partial operating mode with a combustion air ratio of λ

=1.

8. Operating mode according to claim 7, wherein at regions approaching full load, the compression ratio λ

is further lowered in the SI operating mode with a combustion air ratio of λ

=1.