CN-115605679-B - Gas metering valve for an internal combustion engine

Abstract

A gas metering valve for gaseous fuels has a housing (1) in which a gas inlet (7) and a gas outlet (8) for the gaseous fuel are formed. A gas chamber (5) is formed in the housing (1) and connects the gas inlet (7) to the gas outlet (8) in such a way that a gas flow from the gas inlet (7) to the gas outlet (8) is possible. An electrically operable shut-off valve (10) is arranged in the gas chamber (5) for interrupting the gas flow in the gas chamber (5), and an electrically operable control valve (25) is arranged between the shut-off valve (10) and the gas outlet (8), with which control valve the gas flow between the shut-off valve (10) and the gas outlet (8) can be interrupted.

Inventors

• TUERKER OEZGUER
• M. BAYER
• G. Sindhoff
• F. FISCHER
• BROCKI THIERRY
• D. Bosse

Assignees

• 罗伯特·博世有限公司

Dates

Publication Date

20260508

Application Date

20210419

Priority Date

20200514

Claims (10)

1. 1. A gas metering valve for gaseous fuels, having a housing (1) in which a gas inlet (7) and a gas outlet (8) for gaseous fuels are formed, and having a gas chamber (5) which is formed in the housing (1) and which connects the gas inlet (7) with the gas outlet (8) in such a way that a gas flow from the gas inlet (7) to the gas outlet (8) is possible, and having a shut-off valve (10) controllable by an electrical actuator for interrupting the gas flow in the gas chamber (5), Wherein, the An electrically operated control valve (25) is arranged in the gas chamber between the shut-off valve (10) and the gas outlet (8), with which control valve the gas flow between the shut-off valve (10) and the gas outlet (8) can be interrupted, Wherein the shut-off valve (10) and the control valve (25) are configured as solenoid-operated valves, the shut-off valve (10) being actuated by means of a first solenoid (12) and the control valve (25) being actuated by means of a second solenoid (29), wherein the first solenoid (12) and the second solenoid (29) can be actuated independently of one another, such that the shut-off valve (10) and the control valve (25) can be opened and closed independently of one another.
2. 2. A gas metering valve according to claim 1, characterized in that the shut-off valve (10) comprises a movable shut-off valve element (11; 11 ') which cooperates with a shut-off valve seat (14; 14') to interrupt the gas flow in the gas chamber (5).
3. 3. A gas metering valve according to claim 2, characterized in that the shut-off valve element (11; 11 ') is loaded by a shut-off spring (17; 17 ') in the direction of the shut-off valve seat (14; 14 ') with a shut-off force such that the shut-off valve (10) moves against the force of the shut-off spring when the electric actuator is activated.
4. 4. A gas metering valve according to claim 2, characterized in that the shut-off valve (10) is open in the flow direction of the gaseous fuel.
5. 5. A gas metering valve according to claim 2, characterized in that the shut-off valve (10) is opened against the flow direction of the gaseous fuel.
6. 6. A gas metering valve according to any of claims 2 to 5, characterized in that the shut-off valve element (11; 11 ') is coated with plastic at least in the region of interaction with the shut-off valve seat (14; 14 '), and/or the shut-off valve seat (14; 14 ') is coated with plastic.
7. 7. A gas metering valve according to any of claims 1 to 5, characterized in that the control valve (25) comprises a movable control valve element (26) which cooperates with a control valve seat (31) for interrupting the gas flow in the gas chamber (5).
8. 8. A gas metering valve as claimed in claim 6, characterized in that the region and/or the shut-off valve seat (14; 14') is/are coated with an elastomer.
9. 9. Method for operating a gas metering valve according to one of claims 1 to 8, characterized in that for metering the gaseous fuel the shut-off valve (10) is first opened and the control valve (25) is subsequently opened in time.
10. 10. The method according to claim 9, characterized in that during operation of the gas dosing valve, the shut-off valve (10) remains open and the dosing of gaseous fuel is effected only by the control valve (25).

Description

Gas metering valve for an internal combustion engine Technical Field The present invention relates to a gas metering valve, which is preferably used for metering gaseous fuel directly into a combustion chamber or intake duct of an internal combustion engine. Background For example, gas valves for gas metering are known from the prior art, for example from DE 10 2014 225 922 A1. The gas valve disclosed herein comprises a movable valve element which can be moved by an electromagnet against the force of a spring element and thereby open and close the connection between the inlet and the outlet of the gas metering valve. By switching the electromagnet on and off, the gas to be metered can be metered at the desired point in time and in the desired quantity. The sealing seat of the gas valve is close to the outlet, which enables a relatively compact construction on the one hand and also simplifies the precise control of the gas quantity on the other hand. In the direct metering of gaseous fuel into the combustion chamber of an internal combustion engine, the gas metering valve must be arranged close to the combustion chamber. Due to the high combustion temperatures, a strong heating of the gas metering valve can result. For example, if hydrogen is to be metered, a reliable seal can only be achieved with difficulty by means of a metal sealing seat, in particular such a seal being indispensable for safety reasons over the entire service life of the gas metering valve, even if the internal combustion engine is not used for a long time. Therefore, it is necessary to use plastic or elastomeric seals, but such seals cannot be exposed to high temperatures without being damaged. In order to limit the temperature at the seal, the gas metering valve can be designed such that the elastomer-coated seal is relatively far from the outlet and thus the combustion chamber. However, this results in a gas metering valve which is more prone to flame flash back into the gas metering valve, since even when the gas metering valve is closed, the relatively large volume of the gas metering valve is still directly connected to the combustion chamber, due to the sealing seat being remote from the combustion chamber. In particular, when residues of combustible gas are located in the gas metering valve, the flame front of the combustion chamber can propagate into the gas metering valve and there can still lead to a strong thermal load at the sealing seat. Furthermore, the sealing seat remote from the outlet of the gas metering valve makes accurate metering of gaseous fuel difficult because of the relatively large volume between the sealing seat and the outlet. Disclosure of Invention In contrast, the gas metering valve according to the invention has the advantage that reliable metering of gaseous fuel is possible, even if the downtime is long, the tightness of the gas metering valve is not impaired. For this purpose, the gas metering valve has a housing in which a gas inlet and a gas outlet for the gaseous fuel are formed. A gas chamber is configured in the housing, the gas chamber connecting the gas inlet with the gas outlet such that a flow of gas from the gas inlet to the gas outlet is enabled. An electrically operated shut-off valve is arranged in the gas chamber for interrupting the gas flow in the gas chamber. An electrically operated control valve is arranged between the shut-off valve and the gas outlet, with which control valve the gas flow between the shut-off valve and the gas outlet can additionally be interrupted. The gas metering valve thus comprises two electrically controllable valves with which the gas flow in the housing can be interrupted. After the gas metering is completed, the control valve, in particular, the valve of the two valves that is closer to the gas outlet and thus closer to the combustion chamber, can thus be closed in order to prevent heat intrusion. The thermal load of the shut-off valve is thus significantly reduced, so that an elastomer seal can be used on the shut-off valve without problems, which ensures the desired tightness even when the shut-down times of the internal combustion engine and the gas metering valve are long. In an advantageous configuration, the shut-off valve comprises a shut-off valve element which cooperates with a corresponding shut-off valve seat for interrupting the gas flow in the gas chamber. The control valve also advantageously comprises a movable control valve element which cooperates with the control valve seat for interrupting the gas flow, wherein the two valves are preferably designed as solenoid valves. The shut-off valve seat and/or the shut-off valve element are preferably coated with a plastic, preferably an elastomer, in order to achieve a gas-tight seal even when hydrogen is dosed which is not practically completely sealed by a pure metal-to-metal seal. However, a complete seal is not necessary between each injection of gaseous fuel. If another injection is carried