DE2403719A1 - DEVICE FOR USE IN REDUCING THE CONTENT OF POLLUTION IN EXHAUST EMISSIONS FROM COMBUSTION ENGINES - Google Patents

Description

COHAUSZ & FLORACK

j SUBMITTED

PATENT LAW OFFICE O L Π 3 7 1

4 DÜSSELDORF SCHUMANN8TR. 97

PATENT LAWYERS: Dipl.-Ing. W. COHAUSZ Dipl.-Ing. W. FLORACK Dipl.-Ing. R. KNAUF · Dr.-Ing., Dipl.-Wirtsch.-Ing. A. GERBER

The Lucas Electrical Company Limited

Well Street

GB-Birmingham January 24th 1974

Apparatus for use in reducing the level of contaminants in the exhaust emissions of internal combustion engines

The invention relates to a device for use in reducing the level of impurities in exhaust emissions of internal combustion engines.

A device according to the invention is characterized by a reactor through which the exhaust emission from the engine can be conducted is, wherein a catalyst in the Eeaktior is set up so that the exhaust emission flowing through the reactor via the catalyst flows in such a way that impurities in the emission react on the catalyst in such a way that the proportion of impurities in emission is reduced, through a bypass path that the flow of exhaust emissions can be diverted under extreme conditions is, in which the proportion of impurities in the emission exceeds a target value, such that the emission current possibly causing damage to the catalytic converter through the reactor, to control the flow of exhaust emissions through the Reactor and the bypass flow actuatable valve means, which are arranged so that when the proportion of impurities in the emission is below the target value and thus the emission flows through the reactor, part of the emission through the IT bypass flow path is divertable.

Control means are preferably assigned to the valve means which, when the proportion of impurities in the exhaust emission is below the target value, the function of the valve means in such 28 026

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¥ also control that proportion of the emission that leads to any Time is diverted through the Hebenstromweg, from the operating conditions depends on the hotor.

Expediently, that part of the emission depends on the bypass flow path diverted when the level of contaminants is below the set point ', one or more of the operating conditions of the engine, to which the throttle angle, the torque, the driving speed or the engine speed, the air mass flow in the manifold and the manifold underpressure belong; preferably it depends on the pilot speed and the Throttle angle from.

The invention is explained in more detail below with reference to the drawings. In the drawings are:

Fig. 1 is a schematic representation of a gate direction after a Embodiment of the invention when used in connection with an internal combustion engine of a motor vehicle,

Fig. 2 is a circuit diagram showing the arrangement of the control means for controlling the valve means of the in Pig. 1 shown device shows, and

J ¹ Xg. 3 and 4 are schematic representations of further parts of the control means shown in FIG.

According to the drawings, the device has a first and a second Bohr 11, 12, which are parallel to the exhaust manifold 15 of the associated internal combustion engine are connected. Each of the bores 11, 12 is also connected via a two-way proportioning valve 14 to an outlet pipe 15 in which a conventional silencer 16 is provided is. Another muffler 17 is provided in Eohr 12. So when the engine is running, drilling 11 and 12 is constantly exhausting emission, and it flows through the bore to the outlet pipe 15 under the control of valve I4. The valve is arranged so that the exhaust emission to flow all the way through the pipe 11 or completely through the hole 12 or through both holes 11 and 12 in opposite

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changeable conditions can be caused.

Through the pipe 11 are in series with each other a first and a A wide reaction chamber 18 and 19 connected through which the through the pipe 11 exhaust emission flowing can flow. Any reaction chamber carries a catalytic converter which is set up so that the exhaust emission flowing through the chamber passes through the catalytic converter goes. Each catalyst is maintained at an elevated temperature during operation and is arranged to be at this temperature Impurities in the emission react on the catalytic converter. The reaction chambers 18 and 19 thus serves to the proportion of To reduce impurities in the exhaust emission that goes through the pipe 11. The impurities are in the form of Carbon monoxide and unburned hydrocarbons that are made up result from incomplete combustion of the fuel / air mixture fed to the engine or from oxides of Nitrogen resulting from air pollution in the fuel mixture. The chamber 18 is adapted to trap nitrogen oxides present in the exhaust emission, and the chamber 19 sits downstream of the chamber 18 and is used for separation of carbon monoxide and unburned hydrocarbons present in the emission. 3 above there is also an inlet line 21 in connection with pipe 11 between KaaHaem 18 and 19, so that air can be discharged from the chamber 19 during operation, so that a separation of carbon monoxide and unburned carbons in the emission is facilitated. Of course it goes without saying that it is possible to work with a single reactor to separate both types of emission impurities, provided that the operating conditions of the reactor are carefully controlled.

If, during operation, the exhaust emission flows through the pipe 11 and impurities in the emission on the catalysts in the reactors 18 and 19 are deposited, the temperature of the catalysts increases necessarily. Therefore, if the emission is abnormal

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contains large amounts of impurities, there is a possibility of that the temperature of the catalysts rises so sharply that the catalysts are damaged. This can of course happen if either a partial or complete IT failure of the Fuel / air mixture occurs, which is fed to the Hotor. The catalysts in the chambers 18, 19 are therefore temperature sensors 22, 25 assigned, each in the form of thermal elements to have. These are used to monitor the rise in temperature of the catalytic converters. Each sensor is set up in such a way that when the If the temperature of its associated catalytic converter rises above a first setpoint value, the sensor generates an output signal that a valve drive 24 is fed, which the function of the valve I4 controls, during normal running of the engine the arrangement is such that the actuator 24, the valve I4 in an aichen position keeps the exhaust emission from the Kotor through the pipe 11 can flow to allow the separation of contaminants. However, if the proportion of impurities in the emission is the above If the setpoint is exceeded in such a way that one or both of the sensors 22, 25 generates a high output signal, the drive is actuated 24 valve I4 so that the entire emission flow through the Pipe 12 is diverted.

Due to the control that is provided by the sensors 22, 23, so it is possible to ensure that the entire exhaust emission flows from the engine through the reactors 18 and 19, so that the portion of impurities in the emission is reduced, or that if the proportion of impurities in the emission is very large is, the entire emission is diverted through the pipe 12 in order to avoid damage to the catalysts in the reactors 18 and 1 $. However, under certain conditions it may be desirable to reduce at least a portion of the tailpipe emissions through the pipe 12, even if the proportion of contaminants * - ungen in the emission is not high enough to cause possible damage to the catalytic converters. Such circumstances arise when, for example, the running conditions of the engine are such are that the proportion of impurities is considered to be un-

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can be considered harmful, but a passage nonetheless the transmission through the reactors 18, 19 causes changes, which shortens the life of the catalytic converters, for example a high travel speed with low hoist loads. Under these circumstances Experiencing the entire exhaust emission from the engine through the reactors 18 and 19 only leads to unnecessary consumption of catalytic converters in order to shorten the useful life of the catalytic converters. To deal with these situations the drive 24 is set up so that it can be put into operation during normal running conditions of the kotor in order to adjust the setting of the valve 14 in such a way that variable ratios of the exhaust emission to the reactors 18 and 19 flows, can be diverted through the pipe 12.

However, it is preferable to ensure that the share of the emission that through tube 12 during normal engine running conditions is diverted, is such that the remaining emission, which goes through the two reactors 18 and 19 and to the catalysts in the Reactors reacts, just enough to put the catalysts on their to maintain the required operating temperature. Further temperature sensors 26, 27 in turn in the form of thermocouples are therefore the catalysts assigned in chambers 18 and 19, respectively, and each is arranged so that it sends an output signal to the drive 24, when the temperature of its associated catalyst drops below a second set point, that of the lowest effective operating temperature of the catalytic converter.

As can be seen from FIG. J, the drive 24 has a piston 28 which is displaceable in a cylinder 29 and which is connected to the actuating member of the valve 14 in such a way that a movement of the piston results in a change in the setting of the valve 14. The arrangement is such that when the head 28a of the piston 28 is pushed toward end 29a of the cylinder 29, the actuator of the valve 14 is moved to a position such that the valve directs all exhaust emissions through the pipe 11 _P while when the head 28a is pressed against the other i end 29b of the cylinder, the

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Yentil redirects the total exhaust emissions through the Eolir 12. In Intermediate positions of the head 28a allows the valve 14 of the exhaust semission a flow through both tubes 11 and 11.

The movement of the piston 28 is caused by the pressure of a hydraulic fluid controlled to the cylinder 29 via lines 51 and 32 which is connected to the end 29a or 29b of the cylinder are. The lines 31 and 32 are also connected to the cylinder 53 of a control piston valve in connection. Sine movement of the control piston 35 of the valve 34 is through a first and a second Lifting magnets 36 and 37 controlled. The cylinder 33 is also with a Inlet line 38 connected, through the hydraulic fluid from one Memory (not shown) the cylinders 33, 29 via a throttle valve 39 is forwarded by a third party. Kub magnet 41 actuated will. The hydraulic fluid returns to the accumulator via an outlet line 42 with opposite ends of the cylinder 35 is connected. The arrangement is such that when the solenoid 36 is set in operation, the control piston 35 in a first end position is moved, such that hydraulic fluid from Memory can only flow through line 38 to line 3I. the A line 32 is connected to the outlet line 42 so that the piston 28 is pressed towards the end 29b of the cylinder 29 and the valve 14 diverts all exhaust emissions through pipe 12. On the other hand, when the solenoid 37 is activated, the control piston moves 55 in. A second end position, and hydraulic fluid can thereby only flow to line 32 so that piston 28 is pushed towards end 29a with all exhaust emissions flowing through pipe 11. The control piston blocks both lines in intermediate layers 51 and 32, and furthermore the valve 59 is arranged so that then, when the solenoid 4I is in its normal inoperative state is located, the valve restricts the flow of hydraulic fluid in line 398 so that the piston 28 is normally slow relatively migrates to cylinder 29. If both solenoids 36 and 57 during the movement of the control piston 55 between its end positions are de-energized, the piston 28 can therefore remain in an intermediate position, to cause the valve I4 to flow the exhaust

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made possible by both bores 11 and 12.

The operation of the drive 24 and there of the valve 14 is therefore controlled by the lifting magnets 36, 37, 41, while the latter are themselves controlled by the sensors 22, 23, 26 and 2f in accordance with the logic circuit described in Ifig. 2 is shown. In FIG. 2 it is shown that the sensors 22, 23 provide inputs to a GBER sensor circuit 43, while the sensors 26, 27 provide inputs to a HODSR gate circuit 44. The output from the gate circuit 43 is fed to the lifting magnet 41, and it also forms inputs for an OR gate circuit 45 and an iJöBSE gate circuit 46, the outputs of the gate circuits 45 and 46 being used to control the lifting magnets 36 and 37. The other input to the gate circuit 45 comes from an ULTD gate circuit 47t oils in turn receives inputs from the gate circuit 44 and from an electronic control unit 25. The latter also supplies the other input to the gate circuit. The control unit 25 is provided for supplying a switch-on signal whenever it is necessary, under normal conditions, to divert part of the exhaust emission from the associated engine through the drill 12. In this particular embodiment, however, the fuel supplied to the engine is electronically controlled according to the operating conditions of the engine, and it is therefore advisable to ensure that the control unit 25 is the control line for controlling the operation of the engine's fuel supply mechanism. The structure of the control unit 25 will have to be described in detail later.

The operation of the device described above is as follows follows.

V / hen the motor assigned to the door direction is running normally, namely under conditions in which impurities from the exhaust emission must be deposited, the unit 25 is set up so that that no Sinsehaltsignal the logic circuit in Pig. 2 is directed. At this stage, the ITODlfi-Sorsehaltung 46 works so that the hub

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magnet 57 is energized to keep the entire emission through the Jxohr and to direct the catalyst chambers 18 and 19. Under these circumstances Of course, the ITODER gate circuit also works because the catalyst in each of the chambers 18 and 19 the required operating temperature and because the sensors 26, 27 do not provide any output. However, if the operating conditions of the hotor become such that the impurities no longer contribute to the emission which is harmful to the environment is generated by the unit 25 a switch-on signal, the inputs to the gate circuits 46 and 47 supplies. The gate circuit 46 no longer works while the Gate-57 now begins to work and an input · to the OR gate circuit 45 delivers, since of course the gate circuit 44 always still working. The lifting magnet 37 is thus de-energized, and the lifting magnet 36 is energized so that the piston 28 slowly moves the actuator of valve I4 gmoved to reduce part of the exhaust emissions through the Divert pipe 12. The remainder continues to flow through the tube 11. Kit of the movement of the actuator of the valve 14 by the piston 28 a point is reached at which so much exhaust emissions is diverted through the pipe 12 that one or each of the catalysts in the chambers 18, 19 is at its lowest effective operating temperature achieved. In this case one of the sensors 26, 27 delivers or both an input to the EODERJ gate circuit 44 »which is thereby switched off to cause gates 47 »45 to work stop and the solenoid 36 is de-energized. The piston 28 remains then in this intermediate position until the switch-on signal is removed from the unit 25, during which time an unnecessary one becomes Use of the catalysts kept the catalysts at a minimum but are kept at their required operating temperatures. If the linschältsignal is removed of course, works the! fODER Torr.chaltung 46 again, so that the Kubmagnet 37 again is switched on and all emission flows through the tube 11.

If at any time the level of impurities in the Emission becomes so great that the temperature of one of the catalytic converters becomes sufficiently high to cause the associated sensor

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22 or 2J generates an output, the OR gate circuit 43 operates immediately, as can be seen. Firstly, this leads to an excitation of the lifting magnet 41 »to cancel the throttling of the line J8, and second, it leads to the operation of the OR gate 45 » initiate work of the lifting magnet 36. When the proportion of impurities So is very high, the piston 28 migrates quickly into its second bundle position in order to cause the valve I4 to die redirects all emissions through the Eohr 12, so that damage to the catalytic converters is avoided.

Returning to the control unit 25, it can be seen from Fig. 4 that they have a diode matrix 51 with eight first input lines 52a to 52h and eight sets of second input lines 53a to 53h, each of the lines 52a to 52h each of the sets of lines 53a to 53b. crosses. The first input lines have an assignment a first converter (not shown) which, during operation, generates an electrical signal which is a first operating variable of the engine represents. The electrical signal is in the form of a J-bit binary word, and the arrangement is such that one of the lines 52a to 52h is aroused by any of the eight possible combinations for that word. The first operating variable of the engine is selected from the group those from the throttle angle, the torque, the driving speed or the speed of the engine, the air mass flow in the manifold and the manifold negative pressure, and this is preferably the throttle angle. Although in the illustrated Embodiment of each set of lines 53 includes 5 lines, it will be understood that more or fewer lines in each set could be present.

The unit 25 also has a switching device 54, namely ' eight sets of switches 54a through 54h, each connected to lines 53a through 53h, and another set of lines 55a through 55h. The lines 55a to 55h are assigned a second converter (not shown), which generates an electrical signal during operation that represents a second ^ of the operating variables of the engine, before-

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preferably the motor speed. The signal has the form of a 3-bit binary word, that energizes one of the lines 55 »to 55h. The order is such that when a signal appears, for example on the line 55a, the switches 54a with the lines 53a five output lines 56 connected, which are coupled to a decoder ' are. Furthermore, the lines 52 and 53 are connected to one another by means of diodes connected as points in Pig. 1 are shown. The diode connections between each lead 52 and each set of leads are determined by checking the Kotor standing in embossing so that the required signal is obtained at the decoder 57, which corresponds to all values of the first and the second operating variable of the hotor. The output from decoder 57 is of course used to control the operation of the fueling mechanism 58 of the engine. Furthermore however, the Decoaidef is set up to send a switching signal to be supplied to the logic circuit shown in FIG. 3, if certain upstream signals appear on lines 56. These signals of course correspond to the operating conditions of the Kotors, in which the proportion of impurities in the exhaust emission for the environment is harmless.

Expectations

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Claims (8)

Expectations 1. Device for use "in reducing the proportion s, n Impurities in the exhaust emissions from internal combustion engines. characterized by a reactor through which the exhaust emission can be directed from the engine, a catalyst in the reactor being arranged so that the exhaust emission flowing through the reactor flows over the catalyst in such a way that impurities in the emission react on the catalyst in such a way that the proportion of impurities in the emission is reduced, a secondary stream route, through which the flow of the exhaust emission under extreme conditions is diverted, in which the proportion of impurities in the emission exceeds a target value, such that the emission current possibly causing damage to the catalyst by the reactor, to control the flow of exhaust emissions through the reactor and the "Hebenstromweg" actuatable valve means which are so arranged are that if the proportion of impurities in the emission is below the target value and so that the emission flows through the reactor, part of the emission can be diverted through the bypass flow path. 2. VonLchtung according to claim 1, characterized in that a sensor is provided in the reactor for measuring the temperature of the catalyst, the valve means corresponding to that measured by the sensor Temperature can be controlled. J. Device according to claim 1 or 2, characterized by a another reactor through which the exhaust emission can be conducted, the wätere reactor being provided with a further catalyst, the to separate impurities in the exhaust emission other than that is set up by the first catalyst deposited will. 4 · Device according to claim 3, characterized in that a further The sensor measures the temperature of the further catalyst and the valve means are also controlled according to the temperature is measured by the other sensor. 409831/0853 - 2 - 5. Device according to one of claims 1 to 4 »characterized by the valve means associated control means, which at a Percentage of impurities in the exhaust emission below the oil value control the operation of the control means in such a way that the proportion of the emission which at any one time passes through the iT bypass path diverted depends on the operating conditions of the engine. 6. The device according to claim 5 »characterized in that the ■ control means are set up so that the proportion of emission which is diverted through the love stream path when the proportion of impurities is below the setpoint, depends on one or more operating variables of the engine, to which the throttle angle, the Braking torque, the driving speed or the rotor speed, the Air mass flow in the collecting line and the Sanmelle line negative pressure belong. 7. Apparatus according to claim 6, characterized in that the part of the! Emission which is diverted by the love current path when the proportion of impurities is below the target value, depends on the engine speed and the ^ rosselweinkel. 8. Device according to one of claims 5 to 7 »characterized in that that the control means are set up so that when a portion of the emission is diverted through the lifting flow path, the portion the emission going through the or each reactor is so sufficient that its operating temperature is at the required operating temperature is held. 409831/0853