US-20260126018-A1 - METHOD AND DEVICE FOR OPERATING AN INTERNAL COMBUSTION ENGINE USING HYDROGEN

US20260126018A1US 20260126018 A1US20260126018 A1US 20260126018A1US-20260126018-A1

Abstract

A method and a device for operating an internal combustion engine using hydrogen. The hydrogen is injected directly into the combustion chamber of the internal combustion engine. The hydrogen is injected in an angular range later than 40° of crankshaft angle after the closing of an air inlet valve of the internal combustion engine.

Inventors

Holger Kauss
Michael Lippisch
Oezguer Tuerker
Thomas BURTSCHE

Assignees

ROBERT BOSCH GMBH

Dates

Publication Date: 20260507
Application Date: 20251022
Priority Date: 20241104

Claims (10)

1 - 8 . (canceled)
9 . A method for operating an internal combustion engine, the method comprising: directly injecting hydrogen into a combustion chamber of the internal combustion engine, the hydrogen being injected in an angular range later than 40° of crankshaft angle after closing an air inlet valve of the internal combustion engine.
10 . The method according to claim 9 , wherein the angular range for the injection is selected to be as late as possible.
11 . The method according to claim 10 , wherein, for the selection of the angular range, pressure in the combustion chamber due to compression after the closing of the air inlet valve is taken into account.
12 . The method according to claim 10 , wherein, for the selection of the angular range, an amount of hydrogen injected is taken into account.
13 . The method according to claim 10 , wherein, for the selection of the angular range, a center of combustion of the hydrogen is taken into account.
14 . The method according to claim 13 , characterized in that the center of combustion is influenced by selecting an ignition angle of combustion.
15 . The method according to claim 10 , wherein, for the selection of the angular range, a knock susceptibility of a combustion is taken into account.
16 . A device for operating an internal combustion engine using hydrogen injected directly into the combustion chamber of the internal combustion engine, the device being configured to cause the injection of the hydrogen in an angular range later than 40° of crankshaft angle after closing an air inlet valve of the internal combustion engine.
17 . The device according to claim 16 , wherein the device comprises a control device configured to generate signals to cause the injection of the hydrogen in the angular range later than 40° of crankshaft angle after the closing of the air inlet valve of the internal combustion engine.

Description

BACKGROUND INFORMATION Certain methods and devices for operating an internal combustion engine using hydrogen are available, in which hydrogen is injected directly into the combustion chamber of the internal combustion engine. Corresponding internal combustion engines and valves for injecting hydrogen directly into the combustion chamber of the internal combustion engine are described in Germany Patent Application No. DE 10 2023 206 011. SUMMARY A method according to the present invention and a device according to the present invention, by contrast, have an advantage that improved operation of the internal combustion engine is made possible. In particular, knocking combustion in the internal combustion engine is avoided, which allows for more efficient operation of the internal combustion engine. Further advantages and improvements result from the measures of example embodiments of the present invention described herein. By selecting the latest possible angular range for injection, the operation of the internal combustion engine, in particular the knock susceptibility of the internal combustion engine, is improved. By taking into account the pressure in the combustion chamber due to compression, the optimal angular range for injection is optimized. For this optimization, the amount of hydrogen injected and the center of combustion are also advantageously taken into account. The center of combustion may be influenced in particular by selecting a suitable ignition angle. The aforementioned measures optimize the knock susceptibility of the internal combustion engine. Exemplary embodiments of the present invention are illustrated in the figures and explained in more detail in the following description. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an internal combustion engine. FIG. 2 is a characteristic map of knock susceptibility plotted against the hydrogen injection angle. DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS FIG. 1 is a schematic view of a hydrogen-powered internal combustion engine 10 having a cylinder 3 in which a piston 4 is arranged. Above the piston 4, the cylinder 3 forms a combustion chamber 5 into which a mixture of hydrogen and air is introduced and combusted. The combustion of the hydrogen-air mixture in the combustion chamber 5 increases the pressure in the combustion chamber 5 and the pressure is converted into mechanical work by means of a movement of the piston 4 in the cylinder 3, by means of a connecting rod (not shown here) and a crankshaft. Thus, it is a generally conventional Otto internal combustion engine. To supply air into the combustion chamber 5, an intake pipe 2 is provided in which the amount of supplied air is controlled by a throttle valve 1. By opening and closing the throttle valve 1, the amount of air introduced into the combustion chamber 5 is controlled. Furthermore, an injection valve 9 is provided through which the hydrogen is injected directly into the combustion chamber 5. The mixture of hydrogen and air in the combustion chamber 5 is ignited by a spark plug not shown in the drawing. To remove the exhaust gases after combustion, an exhaust pipe 8 is provided through which the combusted exhaust gases are transported out of the combustion chamber 5. Furthermore, an air inlet valve 6 and an exhaust outlet valve 7 are shown schematically in FIG. 1. By opening and closing the air inlet valve 6 and the exhaust outlet valve 7, the combustion chamber 5 is connected to the intake pipe 2 or to the exhaust pipe 8, depending on the operating phase of the internal combustion engine 10. To control the internal combustion engine 10, a control device 11 is also shown, which generates signals for actuating the throttle valve 1 or the injection valve 9. Such an internal combustion engine 10 is typically operated using a four-stroke process. In a first intake stroke, fresh air is sucked into the combustion chamber 5 by the opening of the air inlet valve 6 and the movement of the piston 4 from a top dead center to a bottom dead center. The movement of the piston creates a negative pressure in the combustion chamber, which causes air to be sucked in through the intake pipe 2. By opening the throttle valve 1, the amount of air introduced into the combustion chamber 5 is controlled. This is followed by a compression stroke in which the piston 4 moves from the bottom dead center back to the top dead center, thus compressing the gas in the combustion chamber 5. During this compression stroke, hydrogen is also injected through the injection valve 9 directly into the combustion chamber 5. After the compression stroke, the combustion stroke occurs, in which the mixture of hydrogen and air in the combustion chamber 5 is ignited and combusted by an ignition spark. This combustion greatly increases the pressure in the combustion chamber 5, and this pressure is converted into mechanical work by means of a movement of the piston 4 from top dead center to bottom dead center. Du