Injection and metering device

Abstract

The invention relates to an injection and dosing device (1), in particular for injecting a fluid into an exhaust tract of a combustion engine, comprising a compression and injection space (14), which is designed to receive the fluid to be injected and has at least one injection opening (22); a movable pressure element (4), which is designed such that the pressure in the compression and injection space (14) can be varied by moving the pressure element (4) between an intake position, in which the pressure in the compression and injection space (14) is at a minimum, and an injection position, in which the pressure in the compression and injection space (14) is at a maximum; and a closing element (10), which can be moved between a closing position, in which said element closes the injection opening (22), and an open position, in which said element exposes the injection opening (22). The pressure element (4) and the closing element (10) are coupled via at least two mechanisms of action that are independent of each other, and each of the independent mechanisms of action is capable on its own of having the effect that a movement of the pressure element (4) from the intake position into the pressure position results in a movement of the closing element (10) from the closing position into an open position.

Description

technical field [0001] The invention relates to an injection and metering device, in particular to an injection and metering device for injecting liquid into an exhaust line. Background technique [0002] The requirements placed on the exhaust gas quality of internal combustion engines, in particular internal combustion engines for driving motor vehicles, have been continuously increasing in recent years. Especially in diesel engines NO x Emissions are a problem, which are suppressed by means of so-called SCR catalysts. Environmentally Harmful NO in SCR Catalysts x With the aid of NH, usually in the form of an aqueous urea solution, fed to the catalyst 3 Convert to N 2 and H 2 O. [0003] To deliver the urea solution a dosing system is required, which conventionally consists of an electric dosing pump, which generates the desired injection pressure, and a dosing valve, which dispenses the required injection quantity . The combination of an electric pump and an electr...

AI Technical Summary

Problems solved by technology

The combination of electric pumps and electronically controlled metered dispensing valves is complex and expensive to manufacture, install and maintain

The pressure waves generated by the operation of the metering pump and / or the closing of the valve may be passed between the metering pump and the metering valve through the pressure line required in this combination between the metering pump and the metering valve. pass between, superimpose on each other and lead to undefined opening behavior of the nozzle needle

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