Device for metering fuel into the exhaust system of an internal combustion engine

Abstract

Proposed is a device for metering fuel into the exhaust system of an internal combustion engine. An injection valve is arranged in the exhaust system and is cooled by a flowing cooling liquid even in its closed state. The injection valve is supplied with fuel via a fuel inflow, from which a first partial flow is injected into the exhaust gas and from which a second partial flow is recirculated via a fuel collecting return line into a fuel storage tank. The fuel inflow is fed from a low-pressure system of an injection system which serves for metering fuel for combustions which take place in a combustion chamber of the internal combustion engine. The device has a damping mechanism, which is hydraulically connected to the fuel inflow, for damping pressure oscillations.

1 - 10 . (canceled) 
     
     
         11 . A device for metering fuel to an exhaust system ( 12 ) of an internal combustion engine, having
 an injection valve, which is disposed in the exhaust system and which even in a closed state of the injection valve, is cooled by a flowing cooling fluid, the injection valve being supplied via a fuel inlet with fuel, of which a first partial flow is injected into the exhaust gas and a second partial flow is returned to a fuel tank via a fuel collecting return line, the fuel inlet being supplied a low-pressure system of an injection system, which serves to meter fuel for combustions that take place in a combustion chamber of the engine, wherein the device has a damping mechanism which damps pressure fluctuations, and which communicates hydraulically with the fuel inlet.   
     
     
         12 . The device as defined by  claim 11 , wherein the damping mechanism has a damping volume. 
     
     
         13 . The device as defined by  claim 12 , wherein the damping volume is connected to the fuel collecting return line via a pressure control valve. 
     
     
         14 . The device as defined by  claim 12 , wherein the damping volume is designed as a cooling reservoir, and the injection valve disposed at least partly inside the cooling reservoir. 
     
     
         15 . The device as defined by  claim 13 , wherein the damping volume is designed as a cooling reservoir, and the injection valve disposed at least partly inside the cooling reservoir. 
     
     
         16 . The device as defined by  claim 14 , wherein the injection valve is an electrically controlled injection valve, which is arranged for injecting a quantity of fuel as a function of an electrical trigger signal. 
     
     
         17 . The device as defined by  claim 15 , wherein the injection valve is an electrically controlled injection valve, which is arranged for injecting a quantity of fuel as a function of an electrical trigger signal. 
     
     
         18 . The device as defined by  claim 12 , wherein the damping volume is disposed in the fuel inlet separately from the injection valve. 
     
     
         19 . The device as defined by  claim 18  wherein the device has a pressure-controlled injection valve, which is connected to the damping volume via an electrically controllable metering valve. 
     
     
         20 . The device as defined by  claim 18 , wherein the injection valve is an electrically controlled injection valve, which is arranged for injecting a quantity of fuel as a function of an electrical trigger signal. 
     
     
         21 . The device as defined by  claim 20 , wherein the injection valve is disposed at least partly in a cooling jacket which a cooling medium flows. 
     
     
         22 . The device as defined by  claim 21 , wherein that the cooling jacket is connected to a cooling system of the engine via lines.