Injection system having a device for metering fuel into an exhaust system of an internal combustion engine and a method for this purpose

In an injection system having a device for metering fuel into an exhaust system of a Diesel engine, and a method for controlling the injection of fuel into the exhaust system, wherein the injection system has a high-pressure pump which feeds fuel to an accumulator under high pressure and injectors which inject fuel from the accumulator into the combustion chambers of the internal combustion engine, a fuel spray nozzle arranged in the exhaust system is in communication with the injection system via a fuel metering unit including a control valve and a metering valve and a pressure regulating valve is arranged between the control valve and the metering valve for controlling the pressure of the fuel being metered by the metering valve for injection into the exhaust system via the spray nozzle.