DE10128464A1 - IC engine e.g. Diesel engines with direct fuel injection, and similar has electrically heated catalyst in ventilation pipe to clean blow-by gases - Google Patents

Abstract

The engine has a ventilation pipe (14), leading from crank chamber to intake section, for blow-by gases. The pipe contains a catalyst (18) to clean the gases. The catalyst is heated, esp. electrically, and is integrated in the exhaust train (10) of the engine. An exhaust recycling pipe (22) contains a particle filter (20).

Description

The invention relates to an internal combustion engine according to the features of the preambles of claims 1 and 5.

That in the work cycle or in the compression cycle of a 4-stroke internal combustion engine via the Sealing system piston ring / ring groove So-called blow-by gases are released via an appropriate crankcase ventilation according to the today's requirements returned to the intake tract of the internal combustion engine. Especially in the case of gasoline direct injection with stratified combustion To achieve an optimal mixture preparation in the combustion chamber, a precisely defined one Air movement needed. This air movement in the form of a so-called swirl or tumble is due to the shape of the inlet duct and, if necessary, the installation of panels in the Inlet channel reached. The pollution of the inlet duct and that for air movement responsible organs through the returned blow-by gases has a change air movement and thus an undesirable change in combustion. This problem occurs to the same extent in engines with intake manifold fuel injection not because any deposits in the intake tract (intake manifold) through the injected Fuel can be flushed out.

It is known from the prior art (see, for example, US Pat. No. 2,763,247) which follows blow-by gases discharged outside by the exhaust gases generated during combustion to warm beyond their dew point. From US-PS 945,447 it is still known, the blow-by gases generated during combustion together with the leading the combustion gases to the outside via a catalytic converter.

It is an object of the invention to reach the crankcase during combustion blow-by gases can be traced back to the intake tract of the internal combustion engine without Deposits in the intake tract can form, especially for stratified  Combustion process in connection with a direct injection into the combustion chamber Mixture formation would significantly affect.

The measure of external exhaust gas recirculation known from the prior art, the serves in particular to reduce nitrogen emissions, also leads to the fact that Exhaust gases are returned to the intake tract of the internal combustion engine unwanted deposits in the intake tract of the internal combustion engine. Because the external Exhaust gas recirculation also in connection with stratified combustion processes at Direct injection is applied, there is also the task of taking measures to provide for the deposition of solids from the exhaust gas in the intake tract prevent.

The solution of these two tasks is carried out by the specified in claims 1 and 5 Characteristics. The fact that a catalyst in the crankcase ventilation line the blow-by gases generated during combustion are cleaned, before they get back into the intake tract of the internal combustion engine. In an analogous way When using an external exhaust gas recirculation, it is ensured that the in the Intake tract exhaust gases are cleaned in advance by a particle filter.

Further advantageous refinements and improvements are in the subclaims the internal combustion engine included.

As the temperatures of the returned blow-by gases for the operation of the catalyst are not sufficiently high, the one located in the vent line is placed Heated catalyst in an advantageous manner.

The catalyst can be heated in an advantageous manner in that it is in the exhaust system of the internal combustion engine is arranged and thus flushed with exhaust gas, is heated to higher temperatures. Alternatively, it is also conceivable that Electrically heat the catalyst for the blow-by gases.  

An embodiment of the invention is in the following description and Drawing explained in more detail.

The single figure shows the schematic view of an internal combustion engine.

Description of the embodiment

An internal combustion engine 2 has an intake tract 4 for supplying the combustion air, in which an air filter 6 and a throttle valve 8 are arranged for controlling the quantity of combustion air supplied. An exhaust system in the form of an exhaust pipe 10 is also provided on the internal combustion engine 2 , with the aid of which the exhaust gases produced during the combustion are discharged to the outside. A ventilation line 14 leads from the crankcase space 12 of the internal combustion engine 2 back into the intake tract 4 of the internal combustion engine. Via the ventilation line 14 , the gases which pass from the combustion chamber into the crank chamber in the compression cycle and in the work cycle are fed back to the combustion process in a closed circuit. An oil separator 16 and an oxidation catalytic converter 18 are arranged in the vent line 14 . The catalytic converter 18 , which is designed, for example, as a metal catalytic converter, is located in the exhaust line 10 and is surrounded by hot exhaust gases during operation of the internal combustion engine. The hot exhaust gas heats up the catalytic converter and brings it to a temperature at which the unburned hydrocarbons which have not been separated in the oil separator 16 are burned. This combustion is made possible by the high oxygen content of the blow-by gases. The coating of the catalyst 18 is selected so that it starts up even at low temperatures (approx. 250 ° C.) and reacts insensitively to oil additives, as is the case, for. B. is the case with platinum coatings. This ensures overall that no deposits which change the air movement form in the intake tract 4 of the internal combustion engine.

Between the exhaust gas line 10 and the intake tract 4 of the internal combustion engine 2 , an exhaust gas recirculation line 22 provided with a particle filter 20 is also provided for external exhaust gas recirculation. The particle filter 20 also ensures that the exhaust gases returned to the intake tract 4 are cleaned, so that solid deposits that change the air movement are also prevented in this case. The described method can also be used for direct-injection diesel engines, in which the fuel is also injected directly into the combustion chamber.

Claims (5)

1.Internal combustion engine with an intake tract for supplying the combustion air and a ventilation line leading from the crankcase to the intake tract for (combustion) gases (blow-by gases) which blow through from the combustion chamber to the crankcase, and with an exhaust system for the exhaust gases resulting from the combustion, thereby characterized in that a catalyst ( 18 ) is provided in the vent line ( 14 ) for cleaning the blow by gases. 2. Internal combustion engine according to claim 1, characterized in that the catalyst ( 18 ) is heatable. 3. Internal combustion engine according to claim 2, characterized in that the catalyst ( 18 ) is integrated in the exhaust system ( 10 ) of the internal combustion engine. 4. Internal combustion engine according to claim 2, characterized in that the catalyst ( 18 ) is electrically heated. 5.Internal combustion engine with an intake tract for supplying the combustion air and an exhaust system for the exhaust gases generated during combustion, and with an external exhaust gas recirculation system in which an exhaust gas recirculation line branches off from the exhaust system and opens into the intake tract, characterized in that in the exhaust gas recirculation line ( 22 ) a particle filter ( 20 ) is arranged.