Internal combustion engine
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.
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 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; and
a controller configured to at least control an actuator to control a ratio of hydrogen to ammonia of hydrogen-enriched ammonia provided to the prechamber.
2 . The system of claim 1 , wherein the controller is configured to control the ratio via one or more valves that control a first flow of ammonia through the at least one reformer to generate the hydrogen and a second flow of ammonia through a bypass line around the at least one reformer, and the actuator comprises the one or more valves.
3 . The system of claim 1 , wherein the controller is configured to at least control a lambda of the combustion charge inside each main combustion chamber to be between 0.9 and 1.2.
4 . The system of claim 3 , 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. and below 220° C.
5 . The system of claim 3 , 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).
6 . The system of claim 1 , wherein the controller is configured to control the at least one reformer to provide on-demand production of the hydrogen in an amount adjusted to a hydrogen demand for the prechamber.
7 . The system of claim 6 , wherein the at least one hydrogen source excludes a hydrogen storage tank.
8 . 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 %.
9 . The system of claim 1 , wherein each main combustion chamber has a cylindrical cross-section with a diameter of at least 130 mm, the motion of the piston defines a variable volume geometry of the main combustion chamber having a geometrical compression ratio between 10 and 20, and a brake mean effective pressure of the internal combustion engine is higher than 10 bar.
10 . The system of claim 1 , wherein the controller is configured to control the ratio to increase the ratio with decreases in an engine load, increase the ratio with decreases in temperature of the gaseous medium inside the intake manifold, increase the ratio with increases in temperature of an exhaust gas, and increase the ratio with decreases in pressure of the gaseous medium inside the intake manifold.
11 . The system of claim 1 , wherein the controller is configured to control the intake valves and exhaust valves of the plurality of piston-cylinder-units with overlapping opening times to provide internal exhaust gas recirculation (EGR) with a rate larger than 0% and below 10%.
12 . The system of claim 1 , wherein the internal combustion engine comprises at least one turbocharger having a compressor configured to charge the gaseous medium provided to the intake manifold, the at least one ammonia source comprises a first ammonia source fluidly coupled to a mixer upstream from the compressor, and the at least one ammonia source comprises a second ammonia source fluidly coupled to the prechamber and the at least one reformer.
13 . 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.
14 . The system of claim 1 , wherein the controller is configured to provide ammonia to the main combustion chamber in liquid form, during a period of time from after opening of the at least one intake valve until 50 degrees crank angle before the piston reaches top dead center (TDC).
15 . The 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.
16 . 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;
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; and
a controller configured to at least control an actuator to control a ratio of hydrogen to ammonia of hydrogen-enriched ammonia provided to the prechamber.
17 . The system of claim 16 , wherein the controller is configured to control the ratio via one or more valves that control a first flow of ammonia through the at least one reformer to generate the hydrogen and a second flow of ammonia through a bypass line around the at least one reformer, and the actuator comprises the one or more valves.
18 . The system of claim 16 , further comprising the internal combustion engine.
19 . 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;
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; and
controlling, via a controller, an actuator to control a ratio of hydrogen to ammonia of hydrogen-enriched ammonia provided to the prechamber.
20 . The method of claim 19 , wherein controlling comprises controlling, via the controller, the ratio via one or more valves that control a first flow of ammonia through the at least one reformer to generate the hydrogen and a second flow of ammonia through a bypass line around the at least one reformer, and the actuator comprises the one or more valves.