INTERNAL COMBUSTION ENGINE

Abstract

An internal combustion engine includes an intake manifold, at least one cylinder head with a plurality of piston-cylinder-units, at least one ammonia source, and at least one hydrogen source. Each piston-cylinder-unit includes at least a main combustion chamber, at least one intake valve, a prechamber coupled to the main combustion chamber, and an ignition device in the prechamber. The at least one ammonia source is configured to provide ammonia to each piston-cylinder unit. The at least one hydrogen source is configured to provide hydrogen to each prechamber, wherein the at least one hydrogen source includes at least one reformer for cracking ammonia.

Claims

1. A system, comprising: an internal combustion engine, comprising: an intake manifold configured to provide a gaseous medium to a plurality of piston-cylinder-units; at least one cylinder head with the plurality of piston-cylinder-units, each piston-cylinder-unit of the plurality of piston-cylinder-units having at least: a main combustion chamber configured to combust a combustion charge, wherein a volume of the main combustion chamber is defined by the at least one cylinder head and a reciprocally moving piston; at least one intake valve configured to couple the main combustion chamber to the intake manifold; a prechamber coupled to the main combustion chamber; an igniter arranged in the prechamber, wherein the igniter is configured to start combustion of the combustion charge indirectly via flame torches which enter the main combustion chamber from the prechamber and are created by an ignition of an ignitable air-fuel-mixture inside the prechamber; at least one ammonia source configured to provide ammonia to each piston-cylinder-unit of the plurality of piston-cylinder-units: via the intake manifold and the at least one intake valve as part of gaseous medium in form of a mixture of at least air and ammonia as part of the combustion charge; and via at least one prechamber valve provided to the prechamber; at least one hydrogen source configured to provide hydrogen to the prechambers via the at least one prechamber valve of each piston-cylinder-unit of the plurality of piston-cylinder-units, wherein the at least one hydrogen source comprises at least one reformer configured to crack ammonia.

2. The system of claim 1, wherein the at least one hydrogen source comprises at least one hydrogen tank and/or a hydrogen supply line.

3. (canceled)

4. The system of claim 1, comprising a controller configured to at least control a lambda of the combustion charge inside each main combustion chamber to be between 0.9 and 1.2.

5. The system of claim 4, further comprising at least one intercooler coupled to the intake manifold and the controller being further configured to control the intercooler to provide the gaseous medium to the intake manifold with a temperature of at least 40? C.

6. The system of claim 4, wherein the controller is configured to control the igniter to start combustion of the combustion charge in each piston-cylinder-unit of the plurality of piston-cylinder-units between ?35 degrees to ?10 degrees before top dead center (TDC).

7. The system of claim 4, wherein the controller is configured to at least control an actuator to control a ratio of hydrogen to ammonia of hydrogen-enriched ammonia provided to the prechambers.

8. The system of claim 1, wherein the motion of the piston defines a variable volume geometry of the main combustion chamber having a geometrical compression ratio between 10 and 20.

9. The system of claim 1, wherein the at least one hydrogen source is configured to provide hydrogen to each prechamber in a range of 0 to 10 mass %.

10. The engine system of claim 1, wherein each main combustion chamber has a cylindrical cross-section with a diameter of at least 130 mm.

11. The engine system of claim 1, wherein the internal combustion engine comprises an exhaust manifold coupled to the plurality of piston-cylinder-units by exhaust valves and at least one catalytic converter, coupled to the exhaust manifold.

12. The system of claim 11, wherein the controller device is configured to control the intake valves and the exhaust valves of the plurality of piston-cylinder-units with overlapping opening times to provide internal exhaust gas recirculation, preferably with a rate larger than 0% and below 10%.

13. The engine system of claim 1, wherein the internal combustion engine comprises at least one turbocharger configured to charge the gaseous medium provided to the intake manifold.

14. The system of claim 1, wherein a brake mean effective pressure of the internal combustion engine is higher than 10 bar.

15. The system of claim 1, wherein at least one of the at least one prechamber valve comprises a gas valve configured to provide ammonia in gaseous form to the prechamber.

16. The system of claim 1, wherein the controller is configured to provide ammonia to the main combustion chamber in liquid form after opening of the at least one intake valve until 50 degrees crank angle before the piston reaches top dead center (TDC).

17. The engine system of claim 1, wherein the at least one ammonia source stores ammonia in liquid form and there is provided a heat exchanger to use energy of exhaust gas to evaporate the ammonia into a gaseous form which is then provided to the main combustion chambers.

18. (canceled)

19. A system, comprising: at least one ammonia source configured to provide ammonia to each piston-cylinder-unit of a plurality of piston-cylinder-units of an internal combustion engine: via an intake manifold and at least one intake valve as part of a gaseous medium in form of a mixture of at least air and ammonia as part of a combustion charge; and via at least one prechamber valve provided to a prechamber coupled to a main combustion chamber of the internal combustion engine; and at least one hydrogen source configured to provide hydrogen to the prechamber via the at least one prechamber valve of each piston-cylinder-unit of the plurality of piston-cylinder-units, wherein the at least one hydrogen source comprises at least one reformer configured to crack ammonia.

20. The system of claim 19, further comprising a controller configured to control the at least one ammonia source, the at least one hydrogen source, and the internal combustion engine.

21. The system of claim 20, further comprising the internal combustion engine.

22. A method, comprising: supplying, via at least one ammonia source, ammonia to each piston-cylinder-unit of a plurality of piston-cylinder-units of an internal combustion engine: via an intake manifold and at least one intake valve as part of a gaseous medium in form of a mixture of at least air and ammonia as part of a combustion charge; and via at least one prechamber valve provided to a prechamber coupled to a main combustion chamber of the internal combustion engine; and supplying, via at least one hydrogen source, hydrogen to the prechamber via the at least one prechamber valve of each piston-cylinder-unit of the plurality of piston-cylinder-units, wherein the at least one hydrogen source comprises at least one reformer configured to crack ammonia.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Embodiments of the invention are discussed with reference to FIG. 1.

[0064] FIG. 1 shows an embodiment of an internal combustion engine according to certain aspects of the present technique.

DETAILED DESCRIPTION

[0065] FIG. 1 shows an internal combustion engine 1 comprising an intake manifold 3 which can provide a gaseous medium (air, a mixture of air and ammonia in gaseous form, a mixture of air and ammonia partly in liquid and partly in gaseous form, one of the aforementioned with a combustion promoter in liquid or gaseous form) to a plurality of piston-cylinder-units, at least one intercooler 10 coupled to the intake manifold 3 and at least one cylinder head with a plurality of piston-cylinder-units.

[0066] Each piston-cylinder-unit has at least a cylindrical main combustion chamber 2 for combustion of a combustion charge, a volume of the main combustion chamber 2 being defined by the at least one cylinder head and a reciprocally moving piston, the motion of the piston defining a variable volume geometry of the main combustion chamber 2 preferably having a geometrical compression ratio between 10 and 20.

[0067] Each piston-cylinder-unit is provided with a prechamber 19 in which the ignition device is arranged. The ammonia enriched with hydrogen generated by a reformer 15 is provided to the prechambers 19 via prechamber valves 20 (which can be, by way of example, in the form of injectors).

[0068] Furthermore, each piston-cylinder-unit has at least one intake valve coupled to the intake manifold 3 and an ignition device to start combustion of the combustion charge.

[0069] The internal combustion engine 1 is provided with at least one ammonia source (two ammonia sources 13, 14 are shown in the figures) for providing ammonia to each piston-cylinder-unit as part of the combustion charge via the intake manifold 3 and the at least one intake valve as part of gaseous medium in form of a mixture of at least air and ammonia.

[0070] The internal combustion engine 1 has a control device 12, which is configured to control the intercooler 10 to provide a gaseous medium with a temperature of at least 40? C. to the intake manifold and control a lambda of the combustion charge inside each main combustion chamber 2 to be between 0.9 and 1.2 (in this embodiment by controlling a gas mixer 8 to which one of the ammonia sources 13, 14 is coupled).

[0071] The control device 12 is further configured to control a throttle valve 11 and a first control valve 16, which allows addition of ammonia coming from an ammonia source 14 enriched with hydrogen generated by a reformer 15 to the prechambers 19 via an ammonia supply line 17 and the prechamber valves 20.

[0072] In the shown embodiment, the hydrogen source comprises not only the reformer but also a bypass line in which a second control valve 18 is arranged and the amount of hydrogen-enriched ammonia provided to the ammonia supply line 17 can be adjustably controlled by the control device 12 via the second control valve 18. If no second control valve 18 is provided, a fixed amount of hydrogen-enriched ammonia can be achieved by suitably choosing a pressure of the ammonia source 14 and/or a diameter of the bypass line and/or the dimension of the reformer 15. It should be noted that the provision of a bypass line is not necessary and the reformer 15 could be the only connection between the ammonia source 14 and the first control valve 16.

[0073] Instead of two ammonia sources 13, 14, a single ammonia source 13, 14 to provide ammonia to both the intake manifold 3 and the hydrogen source could be used.

[0074] The gaseous medium provided to the intake manifold 3 is charged by a compressor 7 of a turbocharger 5, which is driven by an exhaust turbine 6 of the turbocharger 5 which is arranged in the exhaust manifold 4.

[0075] A catalytic converter 9 is also coupled to the exhaust manifold 4.

LIST OF REFERENCE SIGNS

[0076] 1 internal combustion engine [0077] 2 main combustion chamber [0078] 3 intake manifold [0079] 4 exhaust manifold [0080] 5 turbocharger [0081] 6. exhaust turbine [0082] 7 compressor [0083] 8 gas mixer [0084] 9 catalytic converter [0085] 10 intercooler [0086] 11 throttle valve [0087] 12 control device [0088] 13 ammonia source [0089] 14 ammonia source [0090] 15 reformer [0091] 16 first control valve [0092] 17 ammonia supply line [0093] 18 second control valve [0094] 19 prechamber [0095] 20 prechamber valve [0096] 21 ammonia source