INTERNAL COMBUSTION ENGINE

Abstract

A system comprising an electronic control unit configured to provide an intake manifold of an internal combustion engine with a mixture of fuel gas, air and exhaust gas with a lambda (λ) of approximately 1 and an exhaust gas recirculation (EGR) content of about 10% to about 45%, wherein the internal combustion engine comprises a prechamber coupled to a main combustion chamber, wherein the main combustion chamber is formed in a cylinder by a piston and at least one cylinder head, wherein a source of a gas-air mixture into the prechamber comprises: an intake port of the main combustion chamber and a connection line between the intake port and a prechamber gas valve of the prechamber; or an intake manifold and a connection line between the intake manifold and the prechamber gas valve of the prechamber.

Claims

1. An internal combustion engine, comprising: at least one cylinder head; an intake manifold; a plurality of main combustion chambers, wherein each of the plurality of main combustion chambers is formed in a cylinder by a piston and the at least one cylinder head; a plurality of intake ports wherein each of the plurality of intake ports is connected to one of the plurality of main combustion chambers and to the intake manifold; a plurality of prechambers, wherein each of the plurality of prechambers is connected to one of the plurality of main combustion chambers and comprises a prechamber gas valve, an ignition device, and a source for a gas-air mixture, wherein the source comprises: the intake port of the main combustion chamber coupled to the respective prechamber and a connection line between the intake port and the prechamber gas valve of the respective prechamber; or the intake manifold and a connection line between the intake manifold and the prechamber gas valve of the respective prechamber; an exhaust gas re-circulation line coupled to the intake manifold; an electronic control unit configured to provide the intake manifold with a mixture of fuel gas, air, and exhaust gas with a lambda (λ) of approximately 1 and an exhaust gas recirculation (EGR) content x.sub.EGR− of about 10% to about 45%.

2. The engine of claim 1, wherein the electronic control unit is configured to provide the intake manifold with the mixture with the lambda (λ) of between about 0.95 and about 1.05.

3. The engine of claim 1, wherein the electronic control unit is configured to provide recirculated exhaust gas to the intake manifold such that the EGR content x.sub.EGR is between about 15% and about 40%.

4. The engine of claim 1, wherein the fuel gas is supplied by a gas mixer upstream of a compressor of a turbocharger or port fuel injection valves positioned downstream of the compressor of the turbocharger.

5. The engine of claim 1, comprising at least one turbocharger configured to provide a pressurized mixture of the air, the fuel gas, and the exhaust gas or a pressurized mixture of the air and the exhaust gas to the intake manifold, wherein the connection lines branch off from the plurality of intake ports or the intake manifold between the at least one turbocharger and inlet valves of the plurality of main combustion chambers.

6. The engine of claim 1, wherein diameters of the cylinders are above 140 mm.

7. The engine of claim 1, wherein inlet and outlet valves of the plurality of main combustion chambers are actuated by a camshaft or an actuator controlled by the electronic control unit such that an inlet valve closes before the piston reaches a lower dead center position.

8. The engine of claim 1, comprising a three-way catalytic converter arranged in an exhaust pipe of the internal combustion engine downstream or upstream of a turbine of a turbocharger.

9. The engine of claim 1, wherein a ratio of a volume of a prechamber of the plurality of prechambers to a compression volume of a respective main combustion chamber of the plurality of main combustion chamber to which the prechamber is connected in an upper dead center of a piston movement ranges from about 0.5% to about 4%.

10. The engine of claim 1, wherein the connection lines are formed as cavities in the at least one cylinder head.

11. The engine of claim 1, wherein a tempering device is provided for each connection line.

12. The engine of claim 1, wherein an aperture is provided for each connection line to decouple the plurality of prechambers from pressure pulsations in the plurality of intake ports.

13. The engine of claim 1, wherein the prechamber gas valve of each of the plurality of prechambers comprises a check valve.

14. The engine of claim 1, wherein the piston of each of the plurality of main combustion chambers comprises a bowl.

15. A system, comprising: an electronic control unit configured to provide an intake manifold of an internal combustion engine with a mixture of fuel gas, air, and exhaust gas with a lambda (λ) of approximately 1 and an exhaust gas recirculation (EGR) content X.sub.EGR of about 10% to about 45%, wherein the internal combustion engine comprises a prechamber coupled to a main combustion chamber, wherein the main combustion chamber is formed in a cylinder by a piston and at least one cylinder head, wherein a source of a gas-air mixture into the prechamber comprises: an intake port of the main combustion chamber and a connection line between the intake port and a prechamber gas valve of the prechamber; or an intake manifold and a connection line between the intake manifold and the prechamber gas valve of the prechamber.

16. The system of claim 15, wherein the electronic control unit is configured to provide the intake manifold with the mixture with the lambda (λ) of between about 0.95 and about 1.05.

17. The system of claim 15, wherein the electronic control unit is configured to provide recirculated exhaust gas to the intake manifold such that the EGR content E.sub.EGR is between about 15% and about 40%.

18. The system of claim 15, comprising the internal combustion engine coupled to a generator.

19. A method, comprising: providing, via control by an electronic control unit, an intake manifold of an internal combustion engine with a mixture of fuel gas, air, and exhaust gas with a lambda (λ) of approximately 1 and an exhaust gas recirculation (EGR) content x.sub.EGR of about 10% to about 45%, wherein the internal combustion engine comprises a prechamber coupled to a main combustion chamber, wherein the main combustion chamber is formed in a cylinder by a piston and at least one cylinder head, wherein a source of a gas-air mixture into the prechamber comprises: an intake port of the main combustion chamber and a connection line between the intake port and a prechamber gas valve of the prechamber; or an intake manifold and a connection line between the intake manifold and the prechamber gas valve of the prechamber.

20. The method of claim 19, wherein the lambda (λ) is between about 0.95 and about 1.05, the EGR content x.sub.EGR is between about 15% and about 40%, the prechamber gas valve comprises a check valve, the piston comprises a bowl, and a 3-way catalytic converter is coupled to an exhaust pipe downstream from the internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] An embodiment of the invention is shown in FIGS. 1 and 2.

[0053] FIG. 1 shows an internal combustion engine 1 according to an embodiment of the invention; and

[0054] FIG. 2 shows a single piston-cylinder-unit 3 of the internal combustion engine 1 of FIG. 1.

DETAILED DESCRIPTION

[0055] The internal combustion engine has a cylinder head 2 (in reality two cylinder heads 2 in V configuration, but only one is shown), a plurality of piston-cylinder-units 3 in which pistons 4 are movably arranged and a plurality of main combustion chambers 5, wherein each main combustion chamber 5 is formed in a cylinder 6 by a piston 4 (cf. FIG. 2) and the cylinder head 2.

[0056] A plurality of intake ports 10 is provided, wherein each intake port 10 is connected to one of the main combustion chambers 5.

[0057] A plurality of prechambers 7 is provided, wherein each prechamber 7 is connected to one of the main combustion chambers 5 and is provided with a prechamber gas valve 8, an ignition device 9 (the ignition timing of which can be controlled by an electronic control unit 19), and a source for a mixture of fuel gas, air and exhaust gas.

[0058] The source for a mixture of fuel gas, air and exhaust gas is formed by the intake port 10 of the main combustion chamber 5 to which the prechamber 7 is connected (shown as an example for all of the prechambers 7 but one) or the intake manifold 12 (shown as an example with respect to the prechamber 7 which is situated second from left in the upper region of FIG. 1), and a connection line 11 provided between the intake port 10 or the intake manifold 12 and the prechamber gas valve 9. Of course, other than shown in FIG. 1, it will be preferred to connect the connection lines 11 of all prechambers 7 either to the intake port 10 or the intake manifold 12.

[0059] In FIG. 1, a mixing device 23 for air and fuel gas and port fuel injection valves 26 are shown together. It is of course preferred to use either a mixing device 23 or port fuel injection valves 26.

[0060] The electronic control unit 19 (dashed command lines are shown only with respect to a single piston-cylinder-unit 3, but are of course provided with respect to all of them) is configured to provide the intake manifold 12 with a mixture of fuel gas, air and exhaust gas via a fuel gas-air mixing device 23 with a lambda λ of at approximately 1 and via an external exhaust gas re-circulation (external EGR) mixing device (having an EGR control device 24 controlled by the electronic control unit 19 and an EGR cooler 25) with X.sub.EGR of approximately 10% to 45%.

[0061] The main chamber and prechamber charge is controlled to have a lambda λ of approximately 1 (preferably between about 0.95 and about 1.05) and a recirculated exhaust gas content X.sub.EGR of about 10% to about 45%, preferably between about 10% and about 45%, more preferably about 15% and 40%.

[0062] If a turbocharger 20 is provided, exhaust gas is provided upstream of a compressor C of the turbocharger 20.

[0063] In this embodiment, the internal combustion engine 1 is provided with at least one turbocharger 20 (having a compressor C and a turbine T) to provide pressurized mixture (air-EGR or air-fuel gas-EGR) to the intake manifold 12. The connection lines 11 branch off from the intake manifold 12 or the intake ports 10 between the turbocharger 20 and inlet valves 15 of the main combustion chambers 5.

[0064] Inlet and outlet valves 15, 16 of the main combustion chambers 5 are actuated by an actuator 22 (which might optionally be controlled by the electronic control unit 19), such that an inlet valve 15 closes before the piston 4 reaches a lower dead center position. It is however preferred to control this motion of the inlet and outlet valves 15, 16 without the electronic control unit 19 via a camshaft.

[0065] A three-way-catalysator (catalytic converter) 14 is arranged preferably downstream of the turbocharger turbine T.

[0066] As an example, a ratio of a volume of a prechamber 7 to a compression volume of the main combustion chamber 5 to which the prechamber 7 is connected in an upper dead center of a piston movement ranges from about 0.5%-about 4%.

[0067] As an example, the connection lines 11 are formed as cavities in the cylinder head 2.

[0068] A tempering device 17 and a throttle 21 can be provided for each connection line 11.

[0069] An aperture 18 can be provided for each connection line 11 in order to decouple the prechambers 7 from pressure pulsations in the intake ports 10 or the intake manifold 12.

LIST OF REFERENCE NUMBERS

[0070] 1 internal combustion engine [0071] 2 cylinder head [0072] 3 piston-cylinder-unit [0073] 4 piston [0074] 5 main-combustion chamber [0075] 6 cylinder [0076] 7 prechamber [0077] 8 gas valve [0078] 9 ignition device [0079] 10 intake port [0080] 11 connection line [0081] 12 intake manifold [0082] 13 exhaust manifold [0083] 14 three-way-catalysator [0084] 15 inlet valve [0085] 16 outlet valve [0086] 17 tempering device [0087] 18 aperture [0088] 19 electronic control unit [0089] 20 turbocharger [0090] 21 throttle [0091] 22 actuator [0092] 23 mixing device [0093] 24 EGR control device of external exhaust gas re-circulation [0094] 25 EGR cooler of external exhaust gas re-circulation [0095] 26 port fuel injection valve [0096] C compressor of turbocharger [0097] T turbine of turbocharger