DE2420678A1 - Catalytic reactor system - for internal combustion engine with start-up and main reactors - Google Patents

Abstract

Internal combustion engine with a catalytic reactor for purifying the exhaust gases, which comprises a main catalytic reactor remote from the exhaust manifold and downstream of a starting catalytic reactor adjacent to the engine and able to be by-passed by a pipe with a closure element, partic. a temp.-controlled throttle butterfly or flap valve. Combines the good start-up properties of a catalytic reactor near the engine with the long life of a reactor under the car floor and remote from the engine.

Description

Internal combustion engine with a catalytic converter The invention relates on a combustion engine with a catalytic converter Purification of the exhaust gases.

It is known, catalysts for the catalytic cleaning of the exhaust gases of internal combustion engines to be arranged in the vicinity of the rotor directly on the exhaust manifold. In addition, underbody catalytic converters are known, which are located at a certain distance from the rotor are mounted under the floor of the motor vehicle.

The advantage of close-coupled catalytic converters is particularly evident in Cold start, since with such an arrangement the catalytic converter is heated up quickly. while at operating temperature Motor the thermal load on a motor installed catalytic converter is higher than that of the underbody catalytic converter.

Underbody catalytic converters, on the other hand, are less favorable for a cold start. Since they are further away from the engine and therefore only warm up slowly, show However, because of their lower thermal load, they can also be used at operating temperature Rotor better serviceability.

The object of the invention is to provide catalysts that both the desired performance in a short time with a cold start as well as with continuous operation and are durable over a long period of use.

This object is achieved by the invention in that one of the The main catalytic converter is located near the engine arranged start catalyst is connected upstream, which by a closable bypass line is bypassable.

This way, when the engine is at operating temperature, no more exhaust gases pass through the starting catalyst are passed, its aging is much less than with a fully loaded catalyst. The full activity of this catalyst remains reserved exclusively for a cold start.

In a further embodiment of the invention, the bypass line can through a throttle valve can be closed, which can be regulated as a function of temperature. Since the both Catalytic converters automatically switched in this way without external access should be that the implementation and the thermal aging result in an optinrum, can control the throttle valve with regard to the flypass line by a temperature of the exhaust manifold sensing bimetallic spring opened at higher temperature and be closed at lower, while at the same time opposing the outlet mouth is closed or opened from the starting catalytic converter.

The throttle valve does not need to be absolutely tight because of the starting catalytic converter the main catalytic converter is connected downstream and thus a small percentage of the Exhaust gases that do not flow through the start-up catalytic converter in the subsequent main catalytic converter is cleaned. This fact that no absolute tightness is required makes it possible it to simplify the valve structure and reduce its price. This Fact is taken into account in the manner according to the invention in that the throttle valve essentially rectangular and with rounded edges in a simple one Form is designed to which no great requirements in terms of their tightness properties need to be asked.

The invention is illustrated schematically in the drawing using one Embodiment explained in more detail in the following description, from the further Details of the subject matter of the invention can be found.

There are shown: FIG. 1 a schematic representation of an exhaust manifold with a starting catalytic converter and the bypass line arranged in its vicinity, as well as one removed from the exhaust manifold arranged II main catalytic converter, Fig. 2 is a section according to the line II - II in Fig. 1 with the throttle valve according to the invention.

Fig. 1 shows an exhaust manifold 1 with one arranged in its vicinity Starting catalytic converter 2, which is accordingly also located near the engine. the Exhaust gases from the internal combustion engine are fed to the starting catalytic converter 2 through an exhaust pipe 3 supplied and they leave the starting catalyst through the outlet port 4, which unites with the end 5 of a flypass line 6. The bypass line 6 is also connected to the exhaust manifold 1 and enables the starting catalytic converter 2 to bypass. At the junction between the bypass line 6 and the outlet mouth 4 a throttle valve 7 is provided. This is followed by an exhaust line 8 on, which feeds the exhaust gases to the main catalytic converter 9.

The throttle valve 7 is essentially rectangular with rounded edges narrow edges 11 formed in a simple shape. Be on the throttle no big demands posed in terms of their tightness.

It is therefore quite possible that there is still column 12 from the throttle valve 7 are not covered, through which still a when the throttle valve is closed Part. the exhaust gases can flow through.

The control of the throttle valve 7 takes over a bimetail spring 13, which closes the bypass line 6 in the cold state and thus the exhaust gas over the starting catalytic converter 2 conducts. By heating the exhaust manifold 1, this becomes Bimetal seated directly on a shaft 14 of the throttle valve 7 on the outside of the manifold heated and thus brings the throttle valve 7 into the dashed line in the drawing marked position in which the outlet mouth 4 geachloæsen and the bypass line 6 is opened so that the exhaust gases now almost exclusively through the main catalytic converter 9 flow through it.

Claims (4)

Expectations 3 internal combustion engine with a catalytic converter Purification of the exhaust gases, that is to say, that one dated Exhaust manifold (1) remotely located main catalytic converter (9> a nearby the engine arranged start catalyst (2) is connected upstream, which by a lockable Bypass line (6) can be bypassed. 2. Combustion fuel machine according to claim 1 d a -d u r c h g e k It is noted that the bypass line (6) can be closed by a throttle valve (7) is, which can be regulated depending on the temperature. 3. Internal combustion engine according to claim 1 or 2, d a d u r to c h S e k e n n n n e i c h n e t that the throttle valve (7) in the Ilinblick on the Bypass line (6) through a bimetal spring that senses the temperature of the exhaust manifold (1) (13) is open at a higher temperature and closed at a lower temperature. 4. Internal combustion engine according to claims 1 to 3, d a d u It is noted that the throttle valve (7) is essentially rectangular is designed with rounded narrow edges in a simple shape to which none great demands are placed on their sealing properties at a glance.