Patent ID: 9556768
Date: 2017-01-31
CPC Classifications: F01N,F02M,Y02T

Claim:
1. A device ( 100 ) for metering a liquid ( 12 ) into an exhaust tract ( 20 ) of an internal combustion engine ( 10 ), wherein the device ( 100 ) comprises at least one injection valve ( 50 ) that can be closed by abutting a closing member ( 61 ) against a valve seat ( 53 ) and that has a cooling circuit ( 75 ) for regulating the temperature in the injection valve ( 50 ), wherein the liquid ( 12 ) is supplied by a pump ( 14 ), to the cooling circuit ( 75 ), through a supply line ( 16 , 17 , 18 ), wherein a restrictor element ( 34 ), distinct from the pump ( 14 ), is connected upstream of the injection valve ( 50 ) for closed-loop or open-loop quantity control of a volumetric flow ( 15 ) of the liquid ( 12 ) through the cooling circuit ( 75 ) of the injection valve ( 50 ), wherein the injection valve ( 50 ) is closed and the volumetric flow ( 15 ) of the liquid ( 12 ) flows through the restrictor element ( 34 ) to the valve seat ( 53 ) when the restrictor element ( 34 ) restricts the volumetric flow ( 15 ) of the liquid ( 12 ) to the injection valve ( 50 ), wherein the injection valve ( 50 ) opens when the restrictor element ( 34 ) releases the volumetric flow ( 15 ) of the liquid ( 12 ) to the injection valve ( 50 ), and wherein the injection valve ( 50 ) comprises a further restrictor ( 62 ) distinct from the valve seat ( 53 ) and arranged in the cooling circuit ( 75 ), which has a greater restricting effect than the restrictor element ( 34 ) when a line cross section ( 16 ) in the restrictor element ( 34 ) is fully released.