US-12624669-B2 - Internal combustion engine

US12624669B2US 12624669 B2US12624669 B2US 12624669B2US-12624669-B2

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.

Inventors

Nikolaus Spyra
Wolfgang FIMML

Assignees

INNIO JENBACHER GMBH & CO OG

Dates

Publication Date: 20260512
Application Date: 20210419

Claims (20)

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.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a National Stage entry from, and claims benefit of, PCT Application No. PCT/AT2021/060128, filed on Apr. 19, 2021, entitled “INTERNAL COMBUSTION ENGINE”, which is herein incorporated by reference in its entirety. BACKGROUND The invention concerns an internal combustion engine in which a main fuel for internal combustion is ammonia (NH3). In another aspect, the invention concerns a genset for generation of electric power. Such internal combustion engines are disclosed in US 2011/0114069 A1, US 2011/0259290A1, EP 2 378 094 A1, US 2010/0019506 A1, and WO 2019/035718 A1. U.S. Pat. No. 3,455,282 discloses an internal combustion engine having main combustion chambers with a compression ratio between 12 and 16, which are provided with a spark plug to start combustion of a combustion charge consisting of air and ammonia. The addition of small quantities of hydrogen as a combustion promoter is discussed. Another internal combustion engine where ammonia is used as a fuel is disclosed in EP 3 669 059 A1. Therein, it is described that pilot ignition with a pre-chamber of an air/ammonia mixture in the main combustion chamber of an internal combustion engine is used in both Otto and diesel engines in order to ensure good ignition of the air/ammonia mixture in an internal combustion engine. The pre-chamber has its own air or air/fuel intake, wherein an air/hydrogen mixture or other carbon containing fuels can be used for pilot ignition. It is further described that hydrogen or other carbon containing fuels can be added to the ammonia/air mixture in the main combustion chamber. BRIEF DESCRIPTION It is an aspect of the invention, in certain embodiments, to provide an internal combustion engine with an improved operability of burning ammonia as a main fuel. It is another aspect of the invention, in certain embodiments, to provide a genset for generation of electric power. These aspects are achieved by an internal combustion engine having the features of the claims and a genset comprising an electric generator coupled to such an internal combustion engine. Embodiments of the invention are defined in the dependent claims. In an internal combustion engine according to embodiments of the invention, there is provided at least: an intake manifold which can provide a gaseous medium (air, or a mixture of air and ammonia in gaseous form, or a mixture of air and ammonia partly in liquid and partly in gaseous form, or one of the aforementioned with a combustion promoter in liquid or gaseous form) to a plurality of piston-cylinder-units,at least one cylinder head with a plurality of piston-cylinder-units, each piston cylinder-unit being provided with a prechamber,at least one ammonia source for providing ammonia to each piston-cylinder-unit as part of the combustion charge (at least one other part of the combustion charge being air) and to the prechambers, andat least one hydrogen source for providing hydrogen to the prechambers via at least one prechamber valve of each piston-cylinder-unit. Aside from the prechamber each piston-cylinder-unit has at least: a (preferably cylindrical) main combustion chamber for combustion of a combustion charge, a volume of the main combustion chamber being defined by the at least one cylinder head and a reciprocally moving piston, the motion of the piston preferably defining a variable volume of the main combustion chamber,at least one intake valve coupled to the intake manifold, andan ignition device arranged in the prechamber to start combustion of the combustion charge indirectly via flame torches, which enter the main combustion chamber from the prechamber and are created by the ignition of an ignitable air-fuel-mixture inside the prechamber. The at least one ammonia source can provide ammonia: to the main combustion chambers via the intake manifold and the at least one intake valve as part of a mixture of at least air and ammonia, andto the prechambers via the at least one prechamber valve provided to the prechamber of each piston-cylinder-unit. In some embodiments, the engine further comprises a control device to operate the internal combustion engine. The at least one hydrogen source can comprise at least one hydrogen tank and/or a hydrogen supply line and/or at least one reformer for cracking ammonia. The use of a reformer as part of the at least one hydrogen source (or as the at least one hydrogen source, if there are no other parts such as a control valve and/or a bypass line) allows on-demand production of hydrogen in an amount adjusted to the need as a combustion promoter in the prechambers. No hydrogen tank for storage of hydrogen is needed. A small reformer can be used. If on-demand production of hydrogen is to be used at least the following operating parameters should be measured using sensors known in the art: engine load, and/ortemperature of the gaseous medium inside the intake manifold, possibly after a turbocharger, if one is