Abstract An exhaust gas aftertreatment device for internal combustion engines having a catalyzer for the selective catalytic reduction of oxides of nitrogen from exhaust gases of motor vehicle diesel engines, provides overstoichiometric supply of NH 3 or materials releasing NH 3 . A first sensor records the NH 3 concentration contained in the exhaust gas and interrupts the supply of the NH 3 quantity when a specified upper threshold value is reached. A second sensor records the NH 3 adsorbed in the catalyzer, by way of which the NH 3 supply is resumed on reaching a specified lower threshold value. Alternatively, only one NH 3 sensor is provided in the exhaust gas aftertreatment device. The NH 3 concentration determined by this single sensor is compared, as the actual value, with a required value corresponding to a specified NH 3 concentration in order to form a correction signal which is used for triggering the metering appliance continuously connected into the gas phase.
An exhaust gas aftertreatment device for an internal combustion engine having a catalyzer for selective catalytic reduction of oxides of nitrogen from exhaust gas, comprising a metering appliance for an overstoichiometric supply of one of NH 3 and materials releasing NH 3 , and at least one NH 3 sensor configured to interrupt the supply when an NH 3 quantity exceeds a specified upper threshold value, and an NH 3 sensor configured to recognize a specific lower threshold value of a stored NH 3 quantity and to resume the supply when, in the catalyzer, the stored NH 3 quantity reaches the specified lower threshold value.
Claim 2
Dependent Claim
105 words
An exhaust gas aftertreatment device for an internal combustion engine having a catalyzer for selective catalytic reduction of oxides of nitrogen from exhaust gas, comprising a metering appliance for an overstoichiometric supply of one of NH 3 and materials releasing NH 3 , and at least one NH 3 sensor configured to interrupt the supply when an NH 3 quantity exceeds a specified upper threshold value, and an NH 3 sensor configured to recognize a specific lower threshold value of a stored NH 3 quantity and to resume the supply when, in the catalyzer, the stored NH 3 quantity reaches the specified lower threshold value.
Claim 3
Dependent Claim
16 words
The device according to claim 1, where the exhaust gas is an diesel engine exhaust gas.
Claim 4
Dependent Claim
54 words
The device according to claim 1, wherein the first NH 3 sensor and the another NH 3 sensor are operatively arranged in the catalyzer such that the first NH 3 sensor measures the NH 3 concentration in the exhaust gas and the another NH 3 sensor measures the NH 3 adsorbed in the catalyzer.
Claim 5
Dependent Claim
61 words
The device according to claim 1, wherein the another NH 3 sensor is operatively arranged in the catalyzer and the first NH 3 sensor is operatively arranged downstream of the catalyzer such that the first NH 3 sensor measures the NH 3 concentration in the exhaust gas and the another NH 3 sensor measures the NH 3 adsorbed in the catalyzer.