Fuel injection system for a spark-ignition internal combustion engine and relative control method

Patent metadata

Field	Value
Publication number	US-11536189-B2
Application number	US-202117202420-A
Country	US
Kind code	B2
Filing date	Mar 16, 2021
Priority date	Mar 17, 2020
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A fuel injection system for a spark-ignition internal combustion engine having a number of cylinders, where a plurality of respective main combustion chambers are defined; a number of first injectors and spark plugs coupled to the cylinders; a number of combustion pre-chambers, each obtained in the area of a respective spark plug; a number of extraction ducts, which originate from a respective cylinder to extract the gas mixture present inside the respective main combustion chamber; a reserve, where the gases extracted by the extraction ducts are mixed with the quantity of fuel needed to obtain a combustion under stoichiometric conditions inside the combustion pre-chambers; and a number of second injectors, each coupled to a respective combustion pre-chamber, into which it injects the gas-and-fuel mixture coming from the reserve.

First claim

The invention claimed is:

1. A fuel injection system ( 1 ) for a spark-ignition internal combustion engine comprising:
a number of cylinders ( 11 ), which receive a gas mixture comprising fresh air and wherein a plurality of respective main combustion chambers (MC) are defined;
a number of first injectors ( 2 ), each coupled to a respective cylinder ( 11 ), into which it injects fuel under pressure during a combustion cycle;
a number of spark plugs ( 13 ), each coupled to a respective cylinder ( 11 ) to cyclically determine the ignition of the fuel present in the main combustion chamber (MC);
a number of combustion pre-chambers (PC), each obtained in the area of a respective spark plug ( 13 ), where the combustion of a gas mixture comprising fresh air and fuel takes place in order to increase the turbulence inside the main combustion chamber (MC) of the respective cylinder ( 11 );
the injection system ( 1 ) is characterized in that it comprises:
a number of extraction ducts ( 17 ; 28 ), each originating from a respective cylinder ( 11 ) in the area of an extraction point (P) to extract the gas mixture present inside the respective main combustion chamber (MC) during a combustion cycle;
at least one reserve ( 18 ), which receives the gas mixture from the extraction ducts ( 17 ; 28 ); inside the reserve ( 18 ), the gas mixture coming from the extraction ducts ( 17 ; 28 ) is mixed with the quantity of fuel needed to obtain a combustion under stoichiometric conditions inside the combustion pre-chambers (PC);
a number of second injectors ( 27 ), each coupled to a respective combustion pre-chamber (PC), into which it injects the gas-and-fuel mixture coming from the reserve ( 18 ); and
an injector system ( 22 ), which feeds the fuel to the reserve ( 18 ) and is connected, by means of a first duct ( 23 ), to a low-pressure pump ( 8 ) or, alternatively, to a high-pressure pump ( 4 ).

2. The system according to claim 1 and comprising a number of fourth injectors ( 20 ), each arranged along a respective extraction duct ( 17 ; 28 ) to extract the gas mixture from the main combustion chamber (MC) of the respective cylinder ( 11 ) and feed it to the reserve ( 18 ).

3. The system according to claim 2 and comprising a number of filters ( 21 ), each arranged along a respective extraction duct ( 17 ; 28 ) and upstream of the fourth injector ( 20 ).

4. The system according to claim 2 and comprising a number of pumping devices ( 29 ) housed along the extraction duct ( 17 ), upstream of the reserve ( 18 ) and downstream of the fourth injector ( 20 ).

5. The system according to claim 1 , wherein each cylinder ( 11 ) houses a respective piston ( 12 ) and the extraction point (P) is obtained above the top dead centre of the stroke of the piston ( 12 ).

6. The system according to claim 1 , wherein each cylinder ( 11 ) houses a respective piston ( 12 ) and the extraction point (P) is obtained under the top dead centre of the stroke of the piston ( 12 ).

7. The system according to claim 1 and comprising a number of first control valves ( 19 ), each arranged along a respective extraction duct ( 17 ) close to the extraction point (P) and designed to regulate the flow of the gas mixture through the extraction duct ( 17 ).

8. The system according to claim 1 and comprising a fuel pressure sensor ( 26 ) arranged along the first duct ( 23 ).

9. The system according to claim 1 , wherein the reserve ( 18 ) is provided with a temperature and pressure sensor ( 24 ) and with a lambda sensor ( 25 ) to read the fuel-air equivalence ratio of the gas-and-fuel mixture.

10. The system according to claim 1 and comprising a number of second ducts ( 28 ), which feed the gas-and-fuel mixture from the reserve ( 18 ) to the respective second injector ( 27 ).

11. The system according to claim 10 and comprising a number of pumping devices ( 29 ) housed along the second ducts ( 28 ).

12. The system according to claim 11 and comprising a pressure sensor ( 30 ; 31 ) for the pressure of the gas-and-fuel mixture, which is housed along the second duct ( 28 ) and is interposed between the pumping device ( 29 ) and the second injector ( 27 ).

13. The system according to claim 11 , wherein the second injectors ( 27 ) are suited both to inject the gas-and-fuel mixture coming from the reserve ( 18 ) into the respective combustion pre-chamber (PC) and to extract the gas mixture from the main combustion chamber (MC) of the respective cylinder ( 11 ) and feed it to the reserve ( 18 ); and comprising a number of third ducts ( 33 ), which feed the gas mixture from the respective main combustion chamber (MC) to the reserve ( 18 ).

14. The system according to claim 13 and comprising a number of second control valves ( 32 ), which are designed to regulate the passage of the gas-and-fuel mixture through the second duct ( 28 ); and a number of third control valves ( 34 ), which are designed to regulate the passage of the gas mixture through the third duct ( 33 ).

15. A method to control an injection system ( 1 ) according to claim 1 and comprising in succession:
a suction step, during which the gas mixture is sucked from the main combustion chamber (MC) of the cylinders ( 11 );
a mixing step, during which the gas mixture coming from the cylinders ( 11 ) is mixed with fuel inside the reserve ( 18 );
an injection step, during which the gas-and-fuel mixture is injected into combustion pre-chambers (PC); and
an ignition step, during which the spark plug ( 13 ) is ignited so as to ignite the gas-and-fuel mixture into combustion pre-chamber (PC).

16. The method according to claim 15 , wherein the suction step and/or the injection step and/or the ignition step of the spark plug ( 13 ) are limited within angular windows of the complete combustion cycle.

Assignees

• Marelli Europe Spa

Inventors

• De Cesare Matteo
• Stola Federico

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02M26/41

  characterised by the arrangement of the recirculation passage in relation to the engine, e.g. to cylinder heads, liners, spark plugs or manifolds; characterised by the arrangement of the recirculation passage in relation to specially adapted combustion chambers · CPC title

• F02B19/109

  with injection of a fuel-air mixture into the pre-combustion chamber by means of a pump, e.g. two-cycle engines · CPC title

• F02B19/1085 Primary

  controlling fuel injection · CPC title

• F02B19/12

  with positive ignition (engines with non-timed positive ignition, and with incandescent chambers F02B9/08) · CPC title