DE2336600B2 - Device for exhaust gas purification from motor vehicle engines - Google Patents

Description

The invention relates to a device for exhaust gas purification with an alternator and a Electric ignition system equipped automobile internal combustion engines with a feed device for Additional air and a cleaning device having a thermal reactor and a downstream catalytic converter, a temperature sensor being provided in the converter with which Measuring pulse the additional air supply device in the event of excess temperature by means of an electrical circuit is lockable '

Such a device is already from the DE-OS 14 76 486 known In this known device, a catalyst device is provided within a combustion chamber, in which two thermocouples are arranged. One thermocouple is capable of supplying additional air via a circuit device throttle while the other thermocouple actuates an igniter for the exhaust gas controls within the catalyst device

This known device is disadvantageous in that it only opens up the possibility of being reached when reaching to throttle the supply of additional air at high temperatures in the catalytic converter device. With modern However, exhaust gas purification devices, which are mandatory by many governments in the interest of reducing environmental pollution, are becoming Not only excessive temperatures are viewed as disadvantageous, but also low temperatures, especially during the Engine starting phase. Undertemperature are dangerous because if one falls below Minimum reaction temperature in the thermal reactor there no afterburning of the exhaust gas takes place which has the consequence that the exhaust gas with its full concentration of pollutants in the catalytic The converter occurs, which results in damage to the same. Therefore, the Internal combustion engine to fear damage to the catalytic converter device because as a result of Undertemperature in the thermal reactor with the entry of exhaust gases too rich in pollutants into the Catalyst device is to be expected

From DE-OS 21 06 608 a safety device for a with an exhaust gas cleaner is provided Internal combustion engine is known in which temperature sensors are provided, the measurement signals of which via a Computer result in the introduction of additional air into the exhaust gas cleaning device. Furthermore are at this known device fuses or bimetal devices provided with their Help the supply of additional air to the afterburning device is switched off in the event of excess temperature in the exhaust gas. In DE-OS 21 06 608 is also a Mentioned device in which the results of temperature measurements are transmitted to a computer which causes time delays in the ignition device, so that the ignition point is set to later if the determined temperatures make an intervention necessary.

From DE-OS 21 35 206 an exhaust gas afterburning device is known in which the additional air supply is blocked as soon as measurements in the

Afterburner temperatures have been determined to be too high

The invention is based on the object of providing a device of the type mentioned at the beginning to train that it quickly comes to operating temperature and in a reliable manner in all operating states of the internal combustion engine an operation that does not overburden the exhaust gas purification device is guaranteed

According to the invention, this object is achieved by that also in the thermal reactor a temperature sensor connected to an electronic computer is provided, with the measuring pulse also the Zusatzluftzuführeinriditung is lockable that a first electrical circuit device is provided, to complete the additional air supply device in the starting phase of the internal combustion engine by means of a provided by the alternator electrical signal is formed, and that one on sub-temperature im thermal reactor responsive, operated by the electronic computer second electrical circuit device is provided, which is used for later setting the Ignition timing of the internal combustion engine is formed

According to a preferred embodiment of the invention it can be provided that in the additional air supply device via the electronic computer or via the first circuit device actuated three-way valve is provided, with the help of which the supply of Additional air can be shut off in the exhaust pipe

Furthermore, it has been found to be advantageous that the first electrical circuit device contains an electromagnetic relay arrangement which has a magnetic coil, that a first fixed contact is provided which is connected to the electronic computer , that a second fixed contact is provided, which is connected to the actuating device for the three-way valve is, and that a movable contact is provided which is in communication with a power source and is designed such that it connects the second fixed contact to the power source for the purpose of actuating the three-way valve as soon as the solenoid is triggered by the electrical signal emitted by the generator of the internal combustion engine during the starting phase is applied

In addition, it can be provided that the second electrical circuit device contains organs for adjusting the ignition point, which comprise an electromagnetic relay, which is triggered by the electronic computer at low temperatures in the thermal Reactor can be acted upon in order to set the ignition point of the internal combustion engine to "late" in order to increase the exhaust gas temperature.

In addition, it can be provided that the organs for adjusting the ignition point have a switch responsive to the temperature of the internal combustion engine have, via which a device for adjusting the ignition device in the direction of pre-ignition is actuatable

An embodiment of the invention is described in t> o the following is described in more detail with reference to the drawing. The single figure shows a schematic representation of the exhaust gas cleaning device.

The internal combustion engine t, also referred to below as a motor, has a cylinder 2 with a Combustion chamber 3. Further are an inlet port 4 with an inlet valve 5 and an outlet or Exhaust opening 6 with an outlet valve 7 is provided.

For the sake of simplicity, only one cylinder 2 is shown in the drawing. To the exhaust opening 6, an exhaust manifold 8 is connected. The exhaust manifold 8 is connected to an exhaust line 9 in which a catalytic converter 10 The exhaust gas opening 6 is supplied with additional air via a nozzle 11 from an additional air supply device 12 acted upon. The additional air supply device 12 comprises an air pump 13 which is driven by the engine 1 is driven, and an additional air supply line 14 with a one-way check valve 15 through which the additional air is guided through the nozzle 11 from the air pump 13 to the exhaust gas or outlet opening 6.

A thermal reactor is arranged in the exhaust manifold 8, which is generally indicated by the reference number 16 The thermal reactor 16 comprises an inner post-combustion chamber 17, which is of a Inner wall 18 is limited by a number of Has openings 19 The reactor 16 also has an outer post-combustion chamber 20 which is delimited by an outer wall 21 and the inner wall 18 The inner post-combustion chamber 17 is connected to the outer post-combustion chamber 20 through the Openings 19 of the inner wall 18 connected. The exhaust gases coming from the engine 1 are internal Afterburning chamber 17 and pass through the openings 19 in the outer afterburning chamber 20, in which the exhaust gases for a while remain until they are fed to the actual exhaust pipe 9. The outer post-combustion chamber 20 is not only used to reduce the dwell time of the Exhaust gases in the reactor lengthen, but also help to increase the temperature of the inner post-combustion chamber to uphold to a reasonable extent; however, it can also be omitted if necessary. on in this way, the exhaust gases in the inner and outer post-combustion chambers 17 and 20 are to be post-burned when they are mixed with the additional air are, under such conditions, that the harmful components contained in the exhaust gases, in one reduced or removed to such an extent that the catalytic converter 10 does not destroy or damaged. In other words, the thermal reactor 16 is designed and constructed so that he keeps catalytic converter 10 under the correct and appropriate operating conditions, i.e. without this through the remaining unburned constituents in the released from the thermal reactor 16 Exhaust gases are destroyed. Above all, it should be emphasized that the thermal reactor 16 is a smaller one Can have afterburning capacity than the previously used, provided as a single afterburning thermal reactor. In accordance with Experiments carried out by the inventor can improve the afterburning capacity of the thermal Reactor 16 be about 35% to 45% of the thermal reactor previously used. In other words: the volume of the post-combustion chamber of the thermal reactor previously used had to be 100% to 200% of the total volume of the combustion chamber of the internal combustion engine, while the volume of the post-combustion chamber of the thermal reactor 16 according to the invention about 35% to 90% of the Has total volume of the combustion chamber of the engine.

As mentioned above, the invention proposes means that prevent overheating and thus destruction or Prevent damage to the thermal reactor 16 and the catalytic converter 10, which is caused by a

causing excessive exothermic reaction under abnormal operating conditions, e.g. B. if the Choke remains inadvertently operated for a long period of time. This will be explained in the following.

In the drawing, the reference number 22 denotes a generator driven by the engine 1, which generates an electrical signal which is fed to an electrical circuit device which contains an electromagnetic relay, which is generally designated by the reference number 23. The relay 23 consists of ι ο a solenoid 24, which is acted upon by the signal coming from the alternator 22, a first stationary contact 25, a second stationary contact 26 and a movable contact 27 which is connected via an ignition switch 28 to an electrical power source 29, e.g. The relay 23 is of the type in which the movable contact 27 is normally connected to the second fixed contact 26, as shown in the drawing. The reference numeral 30 denotes a temperature sensor which is connected to the Outer wall 21 of the thermal reactor 16 is arranged to sense the temperature of the thermal reactor 16, the temperature sensor generating an electrical signal St ₁ analogous to the temperature of the thermal reactor, while the reference number 31 denotes another temperature sensor which is arranged on the catalytic converter 10 sensing the temperature of the catalytic converter 10 and to produce a St ₂ the so temperature of the catalytic converter analog electrical signal. The signals SU and St _2, which are analogous to the temperatures, are fed to an electronic computer 36, which generates an electrical actuation signal Si when the temperature of the thermal reactor 16 rises above a critical value, in the present case above 850 ° C., at which the thermal reactor 16 is destroyed or damaged would, and / or when the temperature of the catalytic converter rises above the critical value in this case o * 750 ⁰ C, wherein the catalytic converter would be destroyed or damaged 10th

On the other hand, the additional air supply device 12 contains a three-way valve 33 to the additional air also to lead back to the air pump 13 through a bypass 34 and the inflow of additional air to the thermal Shut off reactor 16 or to nozzle 11. The three-way valve 33 is operated by a spool 35 one end of which both with the second fixed contact 26 of the relay 33 and with the computer 36 so is connected while the other end of the coil 35 is grounded

During operation, when the ignition switch 28 is closed and the engine is under start-up conditions, the alternator 22 is not energized to the extent that the electrical signal coming from it is sufficiently applied to the solenoid 24. The movable contact 27 then remains with the second fixed Contact 26 is connected and the coil 35 is accordingly acted upon by the battery 29 so that the three-way valve 33 is actuated in order to shut off the additional air flowing from the air pump 13 to the outlet opening 6 through the nozzle 11. The reason for throttling or shutting off the flow of the additional air during the starting process of the engine is that when the engine 1 has to start in a warm state, ie the catalytic converter 10 is already ready for operation, the catalytic converter immediately hits the burned-over exhaust gases as they flow of make-up air would respond, causing such an excessive exothermic reaction that the catalytic converter 10 would be destroyed.

On the other hand, when the engine has come from the starting condition to the normal operating condition, the alternator 22 is energized to such an extent that its electrical signal is sufficiently applied to the solenoid 24 Battery 29 is acted upon. The additional air is therefore conveyed by the air blower 13 through the nozzle U to the outlet opening 6. The electronic computer 36 is then connected to the battery 29 via the first fixed contact 25, which is connected to the movable contact 27 when the temperature of the thermal reactor 16 in this If it rises above 850 ° C., as mentioned above, the computer 36 generates the electrical operating signal 5t which acts on the coil 35 so that the three-way valve 33 is actuated. The additional air is then prevented from flowing into the thermal reactor 16. As a result, the temperature of the thermal reactor 16 falls below 850 ° C., so that the thermal reactor 16 is not overloaded. Similarly, the electronic computer 36 generates, when the temperature of the catalytic converter 10 exceeds 75O ⁰ C in the present case as described above, the electrical operation signal Si which the coil so that the three-way valve 33 is operated applied 35th

The electronically controlled emission control device also contains an ignition timing device, through which the temperature of the exhaust gases emitted by the engine 1 is increased when the temperature of the thermal Reactor 16 falls below the initial reaction temperature

The electronic computer 36 emits a further electrical operating signal £ 2 when the temperature of the thermal reactor 16 drops to the initial reaction temperature, in the present case 650 ° C Breaker camshaft 40, a fixed, grounded contact 41 and a movable contact 42 carried by a movable contact arm 43. The movable contact arm 43 is connected to the primary coil 44a of the ignition coil 44 and also to a capacitor 45, the other end of which is grounded will be carried. The movable contact 49 is connected to a capacitor 50 whose one end is grounded This movable contact 49 is also connected to the primary coil side 44a of the ignition coil 44 through an electromagnetic relay 51st The relay arrangement 51 comprises two fixed contacts 52 and 53, the contact 52 being connected to the primary coil side 44a of the ignition coil 44, while the contact 53 is connected to the retarding device 39, furthermore a movable contact 54 and a coil 55 are provided which, when it is acted upon, the relay arrangement 51 closes. The coil 55 is grounded at one end and the other end is connected to the computer 36 via a switch 56 which is responsive to the engine temperature. The motor switch 56 may be of conventional design and includes

illustrated embodiment two fixed contacts 57 and 58 and a movable contact 59. The Contact 57 is connected to coil 55 of relay arrangement 51, while contact 58 is connected to the electronic computer 36 communicates. The movable contact 59 is arranged around the fixed contacts 57 and then to close 58 when the z. B. by the temperature of the coolant in the not shown Water cooling, which is provided on the engine body, determined engine temperature is low.

If the temperature of the thermal reactor falls below the initial reaction temperature during operation

temperature drops, the electronic computer 36 generates the electrical operating signal & that of the relay arrangement 51 is supplied via the switch 56, so that the coil 55 is then acted upon, whereby the contacts 52 and 53 are connected to each other. In this way, the retarder 39 is actuated and accordingly, the ignition timing is adjusted to "late" so that the exhaust gases emitted by the engine are hotter than that thermal reactor 16 are fed, whereby its temperature above the initial reaction temperature increases and the thermal reactor 16 is ready for operation again.

1 sheet of drawings

909515/179

Claims (5)

Patent claims: 1. Device for exhaust gas purification with an alternator and an electrical ignition system equipped automobile internal combustion engines with a supply device for additional air and a a thermal reactor and a downstream catalytic converter having cleaning device, with a temperature sensor in the Converter is provided, with its measuring pulse the ι ο additional air supply device at overtemperature can be locked by means of an electrical circuit, characterized in that also im thermal reactor (16) is a temperature sensor (30) connected to an electronic computer (36) is provided, with the measuring pulse of which the additional air supply device (12) can also be locked, that an electrical circuit device (23 to 27) is provided, which is used to complete the Additional air supply device is formed in the starting phase of the internal combustion engine by means of an electrical signal supplied by the alternator (22), and that an on-temperature im thermal reactor responsive, actuated via the electronic computer, second electrical Circuit device (39,51,59) is provided which is designed for later setting the ignition timing of the internal combustion engine 2. Apparatus according to claim 1, characterized in that in the additional air supply device (12) one which can be actuated via the electronic computer (36) or via the first circuit device (23 to 27) Three-way valve (33) is provided, with the help of which the supply of additional air into the exhaust gas path (6, 9) is lockable 3. Apparatus according to claim 1 or 2, characterized in that the first electrical circuit device (23 to 27) is an electromagnetic Contains relay arrangement (23) which has a magnetic coil (24) that a first fixed contact (25) is provided, which is connected to the electronic computer (36) that a second fixed contact (26) is provided, which is connected to the actuating device (coil 35) for the three-way valve (33), and that a movable contact (27) is provided which is connected to a power source (29) stands and is designed such that it has the second fixed contact (26) with the power source for the purpose Actuation of the three-way valve (33) connects as soon as the solenoid is activated by the Alternator (22) of the internal combustion engine emitted electrical signal during the starting phase is applied. 4. Device according to one of claims 1 to 3, characterized in that the second electrical Circuit device (29, 51, 52) contains organs (38, 39) for adjusting the ignition point, which an electromagnetic relay (51), which can be acted upon by the electronic computer (36) if the temperature in the thermal reactor (16) is too low is to set the ignition point of the internal combustion engine to "late" in order to increase the exhaust gas temperature to deliver. 5. Device according to one of claims 1 to 4, characterized in that the organs (3El, 39) to Adjustment of the ignition point responsive to the temperature of the internal combustion engine Have switches (56), via which a device for adjusting the ignition device in Direction to advance ignition can be actuated