Metering unit for internal combustion engines operating on combustible gases

Abstract

The invention relates to a metering unit (40) for a gas engine, which metering unit is connected on the inlet side to a gas tank and on the outlet side to a mixture formation device (70) in an air intake channel (12) of the gas engine ) connected. The metering unit (40) has a gas pressure regulator (42) and a gas metering valve (60), through which the gas quantity fed into the mixture forming device (70) is regulated. The adjustment range of the gas metering valve ( 60 ) can be significantly reduced by means of the upstream gas pressure regulator, so that the gas can be metered more easily and precisely. The invention also relates to an internal combustion engine (10) which is operated with a combustible gas and in which such a metering unit (40) is arranged on the intake channel (12) of the internal combustion engine, the invention also relates to a device for use in such Method for pressure regulation in metering unit (40).

Description

Technical field [0001] The present invention relates to a metering unit for an internal combustion engine operated by the combustible gas, an internal combustion engine such a metering unit and a method for adjusting the pressure in the metering unit has. Background technique [0002] It is known from the prior art internal combustion engine, which, for example, liquefied natural gas (LPG-Liquified Natural Gas) or a pressure gas reservoir (CNG-Compressed Natural Gas) running through the combustible gas. Especially for the storage of natural gas at a pressure (CNG) challenge is to deliver gas in a combustion chamber. As compared to gas (incompressible some extent) a liquid having a significantly higher compressibility, so that the gas can not be injected into a conventional fuel pump of a combustion chamber. Although direct combustible gas injection in a combustion chamber (similar to the liquid fuel directly injected) is possible, but it requires at least 20bar gas canister havin...

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Problems solved by technology

[0007] Known solutions are either not suitable for the highly dynamic operation common in internal combustion engines in passenger cars and vans, or are very expensive and are therefore intended for stationary gas engines

Since the gas and fresh air quantities required in internal combustion engines, especially those with supercharging, differ by up to a hundred times between idling and full load operation, extremely precise adjustments by means of pressure regulators are required, In the metering device proposed in EP 2 615 278 A, therefore, small deviations can lead to significant fluctuations and inaccuracies in the regulation, which in turn lead to a perceivable loss of comfort and worsening of the emissions of the internal combustion engine, especially in idling operation Medium (so-called idling jerk)

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