Device and method for regenerating particulate filters, use of a medium for regenerating particulate filters, and refill pack comprising said with the medium

Abstract

The invention relates to the use of a combustion fuel that differs from diesel or diesel cleavage products, in particular monoethylene glycol and/or methanol, for enriching exhaust gas in front of a particulate filter ( 19 ) of a diesel engine ( 11 ), in order to heat the exhaust gas by means of a catalytic oxidation of this combustion fuel to a temperature sufficient for a regeneration of the particulate filter ( 19 ). It also relates to the device that permits this use and to this end comprises a combustion fuel tank ( 25 ) and a combustion fuel line ( 27 ) connected to an exhaust gas train ( 17 ) of a diesel engine ( 11 ), the combustion fuel tank ( 25 ) of which is not the diesel tank ( 15 ) of the diesel engine. Furthermore, the invention can also comprise the diesel engine ( 11 ) and the tank ( 15 ) thereof, as well as the exhaust gas train ( 17 ) with the particulate filter ( 19 ). The concept common to all of these aspects of the invention is expressed in the method that is characterized by the steps that a combustion fuel, in particular methanol and/or ethylene glycol is added to the exhaust gas of a diesel engine ( 11 ) in front of its particulate filter ( 19 ), so that it in a gaseous state oxidizes on the catalyst surface ( 21 ) and thereby heats the exhaust gas to a temperature at which the regeneration of the particulate filter can be carried out. Due to the combustion fuel tank ( 25 ) separate from the propellant fuel tank ( 15 ), a combustion fuel can be used for this purpose which reacts with the catalyst ( 21 ) at exhaust temperatures too low for diesel.

1 . A method for regenerating a particulate filter of a diesel engine, comprising:
 enriching an exhaust gas when the exhaust gas temperature is below a predetermined temperature, the exhaust gas enriched at a feed point upstream of a particulate filter with a catalytically oxidizable medium; and   heating the exhaust gas through catalytic oxidation of the catalytically oxidizable medium to an exhaust gas temperature sufficient for a regeneration of the particulate filter, the exhaust gas enriched with a combustion fuel that differs from a propellant fuel and cleavage products thereof, the combustion fuel oxidizing on the catalytically oxidizable medium at a temperature that is lower than a propellant fuel temperature.   
     
     
         2 . The method of  claim 1 , further comprising heating the exhaust gas enriched with the combustion fuel to a first temperature, at which the combustion fuel can be catalytically oxidized, and simultaneously or subsequently enriching the exhaust gas with the propellant fuel. 
     
     
         3 . A method of using a catalytically oxidizable medium for enrichment of an exhaust gas of a lean-burn engine, comprising: providing a catalytically oxidizable medium for heating an exhaust gas through catalytic oxidation of the medium to an exhaust gas temperature sufficient for the regeneration of a particulate filter; and
 providing a combustion fuel that differs from a propellant fuel of the lean-burn engine and the cleavage products thereof, the combustion fuel being catalytically oxidizable at a lower temperature than the propellant fuel.   
     
     
         4 . The method of  claim 3 , wherein providing the combustion fuel further comprises providing a combustion fuel that is or contains an organic liquid. 
     
     
         5 . The method of  claim 4 , wherein providing the combustion fuel further comprises providing a combustion fuel that is an alcohol or a mixture containing at least 40% alcohol. 
     
     
         6 . The method of  claim 4 , wherein providing the combustion fuel further comprises providing a combustion fuel that is methyl alcohol or a mixture containing at least 10% methyl alcohol. 
     
     
         7 . The method of  claim 4 , wherein providing the combustion fuel further comprises providing a combustion fuel that is at least one of a glycol, a monoethylene glycol, a propylene glycol, or a mixture containing at least 10% glycol. 
     
     
         8 . The method of  claim 3 , wherein providing the combustion fuel further comprises providing a combustion fuel that has a volatilization temperature that is lower than an average volatilization temperature of the propellant fuel. 
     
     
         9 . The method of  claim 8 , further comprising providing a combustion fuel wherein the volatilization temperature is below a minimum exhaust gas temperature necessary for a catalytic reaction of the propellant fuel. 
     
     
         10 . The method of  claim 3 , wherein providing the combustion fuel further comprises providing a combustion fuel that is dissolved in water. 
     
     
         11 . A device for regenerating a particulate filter, comprising:
 a combustion fuel tank;   a combustion fuel line coupled to the combustion fuel tank;   a conveyance device for conveying a combustion fuel from the combustion fuel tank through the combustion fuel line   a lean burn engine,   a propellant fuel tank for supplying propellant fuel to said lean burn engine,   an exhaust gas system coupled to said lean burn engine, and   a particulate filter in the exhaust gas system, the combustion fuel line arranged upstream of the particulate filter opening into the exhaust gas system, so that exhaust gas can be enriched with a combustion fuel from the combustion fuel tank prior to entering the particulate filter.   
     
     
         12 . A device for regenerating a particulate filter, comprising:
 a lean burn engine,   a first fuel tank for supplying a first fuel to the lean burn engine,   a first fuel line from the first fuel tank to the lean-burn engine,   an exhaust gas system coupled to the lean burn engine,   at least one catalytic surface and a particulate filter coupled to the exhaust gas system,   a second fuel tank ( 25 ), separate from the first fuel tank, for accommodating a second fuel different from the first fuel and the cleavage products thereof,   a second fuel line opening into the exhaust gas system from the second fuel tank ( 25 ) to a feed point in the exhaust gas system, that is upstream of the particulate filter and the at least one catalytic surface, and   a conveyance device for conveying the second fuel into the exhaust gas system and a circuit for activating the conveyance device.   
     
     
         13 . The device of  claim 12 , further comprising a sensor for monitoring at least one of pressure and temperature in the exhaust gas system and for activating the circuit. 
     
     
         14 . The device of  claim 12 , further comprising a warning device connected to the circuit to indicate a necessity of a regeneration of the particulate filter. 
     
     
         15 . The device of  claim 12 , further comprising a refill package containing the second fuel that is comprised of an alcohol.