JPH05187225A - Electric heating catalyst control device - Google Patents

Abstract

PURPOSE:To perform the reliable starting of an engine by providing a power source for an electric heating catalyst independently from a power source for controlling an engine and controlling an energizing amount so that a detected electric heating catalyst temperature is adjusted to a value approximately equal to a set temperature, in an electric heating catalyst control device for an automobile engine. CONSTITUTION:Through turning ON of a key switch 13, a control circuit 5 performs feedback control by means of a set catalyst temperature and the detected temperature of a temperature sensor 6 installed to a front catalyst 2. Namely, duty control is made on the base of a transistor 11 so that the temperature of the front catalyst 2 is adjusted to a value approximately equal to a set temperature to control energization to the front catalyst 2. An independent battery 15 is arranged as a power source to the front catalyst 2, a charger 14 is provided, and a voltage is set to a value, for example, 24V, equal to or higher than that of a battery 4 for an engine. The charger 14 employs an alternator different from an alternator for controlling an engine. This constitution prevents lowering of capacity of the battery for engine and causes execution of a reliable starting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst device suitable for use in purifying exhaust gas from an automobile engine.

[0002]

2. Description of the Related Art A conventional electric heating catalyst control device is
A E, Technical, Paper, Series, 900503
(1990) Item 61 to Item 70 (SAE, Technical, Pa
per, Series, 900503 (1990) Page, 61-70), the catalyst is composed of a resistor-type metal carrier and is heated by passing an electric current through it. It can be improved. Such electrically heated catalysts are designed to reach a catalyst activation temperature of about 350 ° C. within 30 seconds using a conventional 12V power system. These control means are provided with catalyst heating current supply means and catalyst temperature detection means so that the temperature can be raised to a desired catalyst operating temperature.

[0003]

In the above-mentioned prior art, no consideration is given to the power supply for supplying the current to the catalyst, and if the charge capacity of the battery decreases, it becomes difficult to drive the starter used when starting the engine. There was a problem that the engine could not be started. That is, since the required amount of power required to heat the catalyst is about 4.7 KW, a considerable electric load is applied to the conventional power source, resulting in discharge and deterioration of the power source. In addition, in order to minimize exhaust gas pollution, it is desirable that the catalyst is heated prior to starting the engine so as to approach the catalyst activation temperature when starting the engine. As a result, the charging ability of the power source is deteriorated, and it becomes difficult to start the engine by the starter.

The present invention is to solve the above problems. A first object of the present invention is to ensure starting of an engine by making an engine starting power source independent from a power source for supplying a current to the electrically heated catalyst. A second object of the present invention is to increase the transmission efficiency as a power source by using a voltage higher than that of the engine starting power source for the independent power source. As a result,
It is possible to realize a low cost, small size and lightweight power supply control device.

Specifically, the object of claim 1 of the present invention is to:
When the catalyst temperature is heated to improve the purification efficiency of unburned gas and the amount of HC and CO emissions in the gas is reduced, the power supply for supplying the current to the catalyst is independent of the power supply for engine control. This ensures the starting and control of the engine. Further, an object of claim 2 of the present invention is to provide a control device which is low in cost and lightweight in order to improve power transmission efficiency by making the independent power source equal to or higher in voltage than an engine control power source. Is. Further, an object of claim 3 of the present invention is to accelerate the purification of gas which is released immediately after the engine is started by heating the catalyst before the engine is started. An object of claim 4 of the present invention is to set the heating target temperature of the catalyst to 350 ° C. because the activation temperature of the catalyst is around 350 ° C., and to prevent unnecessary power consumption. .. An object of claim 5 of the present invention is to provide a method for efficiently heating and controlling an electrically heated catalyst in a short time. This makes it possible to rapidly heat the catalyst, and by controlling the temperature, unnecessary power can be prevented. The object of claims 6 and 7 of the present invention is to provide a charging means and charging control for this power source by providing a power source independent of the engine.
By using a C / DC converter or alternator as a charger, downsizing is possible and the space on the vehicle can be saved. The object of claim 8 of the present invention is to provide an AC / AC independent power source.
When charging with the DC converter, consideration is given to charging with the AC / DC converter after the start of the engine is completed so that the load does not become a load on the engine control power supply. An object of claim 9 of the present invention is to provide a charge control means for charging with an AC / DC converter.

As a result, unnecessary charging / discharging can be eliminated and the life of the power source is not deteriorated. Claim 10 of the present invention
By arranging the electrically heated catalyst at a position upstream of the exhaust gas with respect to the conventional main catalyst, it becomes possible to receive the heat of the exhaust gas, and it is possible to reduce the required electric power amount of the electrically heated catalyst. It will be possible. The object of claim 11 of the present invention is to install the current control means for the electrically heated catalyst in the engine control device, which makes it possible to save the space as the control device, which is advantageous in vehicle installation.

Further, in the twelfth aspect of the present invention, when there is only one power source (when the electric heating catalyst heating power source and the engine driving power source are shared), the starter driving power source becomes a high load state and the starter does not operate. The purpose is not to become. In the thirteenth aspect of the present invention, the method for detecting the starting state of the engine is considered, and it is determined whether the engine is in the cranking state by the starter switch signal or the engine speed.

[0008]

The electrocatalyst control device of the present invention is intended to achieve the above-mentioned object. The means are a catalyst that is heated by the passage of an electric current, and a catalyst for heating the electrocatalyst. The temperature detection means for detecting the temperature, the control means for controlling the energization current of the electrically heated catalyst, the power source independent of the engine control power source, and the charging means for charging the power source independent of the engine control power source are provided. Can be achieved.

In the case where there is only one power source, this can be achieved by stopping the electric power supply to the electrically heated catalyst while the starter is in a driving state.

[0010]

According to the structure of the electrocatalyst control device of the present invention described above, the temperature is detected by the temperature detecting means of the catalyst and the current is passed through the catalyst by the controlling means to heat the catalyst before the engine is started. Therefore, the efficiency of purifying the gas can be increased immediately after the engine is started, and the amount of HC and CO emissions in the gas can be reduced. Further, by setting the power supply voltage for supplying the current to the catalyst higher than the power supply voltage for starting the engine, the current supplied to the catalyst can be suppressed to be low, and the weight of the wiring can be reduced, the control device can be downsized, and the power transmission efficiency can be reduced. Can be improved.

When there is only one power source, the starter stops the electric power supply to the electrically heated catalyst in the driven state, so that the starter drive power source does not go down due to the electrically heated catalyst electrical load.

[0012]

Embodiment 1 Embodiment 1 of the present invention will be described below with reference to FIG.

FIG. 1 is a conceptual block diagram showing the overall structure. First, the unexposed gas exhausted from the internal combustion engine 1 passes through the front catalyst 2 and the main catalyst 3 which is larger in volume than the front catalyst 3.
Is released to the outside air via The front catalyst 2 includes a temperature sensor 6 for detecting the temperature of the catalyst and two terminals 7 for supplying an electric current.
An electrically heated catalyst (EHC) described in SAE Paper (900503). In the embodiment of the present invention, (EHC) is shown as the precatalyst. However, when there is more than one (EHC) precatalyst with respect to the main catalyst, or when both the precatalyst and the main catalyst are (EHC). Is also applicable. One of the two terminals 7 for supplying current is the battery 1
5 and another terminal 7 are engine control devices (EC
U) 5 of the transistor N-P-N11 is connected to the collector. Although not shown in FIG. 1, the engine control device 5 performs switching control of a relay unit that performs ON / OFF control of the current to the front catalyst 2, a transistor 11 that generates an (EHC) control signal, and a temperature sensor 6. The control circuit 12 receives a signal from the. As a result, the control circuit 12 generates a duty drive signal for the base of the transistor 11. The emitter of the transistor 11 is connected to the negative terminals of the batteries 4 and 15. On the other hand, the battery 4 is a conventional 12V battery connected to the alternator 8, the starter motor 9, and the electric load 10. The ignition switch 13 is connected between the control circuit 12 and the battery 4.

With respect to the present invention, the independent battery 15 preferably has a voltage equal to or higher than that of the battery 4, for example, 24V, and the charger 14 dedicated to this battery 15 is provided. The charger 14 may be an alternator other than the engine control alternator, a three-phase transformer and an AC / DC converter as shown in FIG. Battery 15
Are separated and independent of the battery 4 except for the ground line.

Next, the operation will be described based on the above-mentioned overall structure. When the key switch 13 is turned on, the control circuit (ECU) 5 equipped with a microcomputer uses a preset catalyst temperature set value (about 350 ° C.) as a command value,
Feedback control is performed using the signal of the temperature sensor 6 as a feedback value.
In this way, the control circuit 12 controls the duty of the base of the transistor 11 so that the temperature of the front catalyst 2 approaches the set value. (In the present embodiment, an example in which duty control is performed is shown, but if the heat capacity of (EHC) is large, ON / OFF control of the relay may be simply performed.) As a result, when the temperature of the front catalyst 2 reaches 350 ° C, Transistor 1 to stop the current supply for heating precatalyst 2
1 is turned off. The current supplied according to the ON duty of the transistor 11 flows through the battery 15, the front catalyst 2, and the transistor 11, and generates heat due to the electric resistance value of the front catalyst 2. Therefore, when the engine is started by the battery 4 and the starter motor after the heating of the catalyst is completed, the efficiency of purifying the gas of the catalyst is sufficiently high, and harmful components such as HC and CO contained in the gas are significantly increased. It can be removed. Further adding, even if the charge amount of the second independent battery 15 is reduced because it is consumed for heating the front catalyst 2, the drive battery 4 for the starter motor for starting the engine is independent of the catalyst heating battery 15. Therefore, there is no difficulty in starting the engine.

Next, with reference to FIG. 2, a battery charging circuit and an electrocatalyst heating circuit will be described with reference to the first embodiment of the present invention.

In FIG. 2, the ignition switch 1
3 is connected in series with the ignition warning light 21 and in parallel with the ballast resistor 22. The ignition warning light 21 is connected to an IC regulator 23 built in the alternator 8. The alternator 8 constitutes a Y connection of the stator for outputting a three-phase AC output. The three-phase AC output of the stator 24 is normally rectified to 12V by the diode 25 and supplied to the electric load 10 and the battery 4. Normal induction coil 2
6 is installed as a known built-in circuit between the positive terminal of the battery and the regulator 23. With respect to the present invention, the three-phase AC output from the stator coil is connected to the charger 14, which in the embodiment of FIG. 2 is 12V to 24V.
To the AC / DC converter 2
Sent to 8. As shown in FIG. 2, the battery 15 has 12
A 24V battery with two V batteries connected in series,
The (EHC) 2 is supplied with power and connected to the AC / DC converter 28 to be charged. The stator 24 and the three-phase transformer 27 are connected to the line 32 by the (ECU) 5.
It is connected via a relay 31 controlled through. Then, the charging of the 24V battery 15 is selectively turned on / off by the (ECU) 5 as needed. The voltage of the battery 15 is monitored by the (ECU) 5 via line 33. The output of the temperature sensor 6 is also monitored by the (ECU) 5 via line 34. Further, the (ECU) 5 is connected to the main relay 37.
To the sub-relay 36 installed to selectively transmit the switching signal for the EHC through the line 35.
Send the energization control signal. The main relay 37 is (EH
C) A relay for switching the current of about 250 amperes from the battery 15 for 2, which is a high current compatible relay.

As shown in FIG. 1, the (EHC) control circuit 12 is preferably incorporated in the engine control device 5, but as shown in FIG. 3, it is independent of the engine control device 5. The control circuit 300 can be simply used.
It may be placed inside.

Next, FIG. 3 will be described.

The (EHC) control circuit 12 has an OR gate 3
01, and receives input signals of the starter motor 9 and the engine speed signal (Ne). The OR gate 301 is
An output signal indicating whether the operating condition of the starter motor 9 or a predetermined engine speed is reached is transmitted to the engine start completion judging means 302. From 302 to line 3
Means 3 for determining the charging voltage of the battery 15 via 2
AC / DC depending on the output state of 03, 304
A signal for controlling the operation of converter control relay 31 is transmitted. Here, 304 is a means for determining whether the charging voltage of the battery 15 is lower than a predetermined target voltage, and 303 is whether the charging voltage of the battery 15 is equal to or higher than the predetermined target voltage. Is a means for determining.

Next, the temperature detected by the temperature sensor 6 becomes an input signal of the (EHC) warm-up completion temperature determination means 305, and if it is lower than a predetermined target temperature, the (EHC) control signal line. 35 through (EH
C) The output signal is transmitted to the current control relays 36 and 37. At this time, of course, this output signal also depends on the output signals of 303 and 304, and the propriety of transmission is determined.

Although the ignition switch 13 is a conventional one, it has at least three-stage positions and is a power-off position in which the so-called battery 4 is disconnected from all electric loads, and then a power-on position (so-called key). Switch-on), and finally the induction coil 2 for driving the starter motor 9
6 has a position to start energization and start the engine.

When the power ON position is reached for the first time after the ignition switch is turned off, this is judged by the power ON position judging means 306, and if it is judged ON, the engine start completion judging means 302
A connected to receive an engine stop determination signal (meaning so-called engine OFF state) sent from A
The ON determination output signal is transmitted to the ND gate 307.
When these two signals are both input, AND gate 3
07 outputs an output signal to the (EHC) current control relays 36 and 37, and outputs an output signal to the (EHC) preheat possibility determination means 308.

Next, the operation of each relay will be described.

When the engine start completion judging means 302 judges that the engine start is completed, 3 if the charging voltage of the battery 15 is equal to or exceeds the predetermined target value.
When the determination is made in 03, the AC / DC converter control relay 31 is turned off to cut off the charging line of the battery 15. Then, in order to supply power from the battery 15 to (EHC) 2, (EHC) current control relay 3
Turn on (EHC) control signal to turn on 6, 37
Let If the voltage of the battery 15 is lower than a predetermined target value and the engine has already started, the AC / DC converter control for charging the battery 15 from the AC / DC converter 28 via the line 29. An ON signal for turning on the relay 31 is output from 304. At this time, the relay 36 for controlling the relay 37 is turned off (EHC) to turn off the control. By effectively utilizing the determination results of the means 303 and 304, if the voltage of the battery 15 is sufficient, AC
The power can be saved by not operating the / DC converter 28, while the power supply to the front catalyst 2 is stopped when the power of the battery 15 is very low.

Since it is desirable that the front catalyst 2 be preheated before the engine is started, when the engine stop state is detected, an input is made to the AND gate 307, and the ignition switch is set to the power ON position,
Means 308 based on the determination results of the means 303, 304
Outputs a command signal for turning on the (EHC) current control relays 36, 37. At this time, the control time for preheat heating can be varied by a time timer that can be arbitrarily set according to the capacity of the electrically heated catalyst, the required amount of power required for heating, and the power supply capacity.

Next, the control timing of each control will be described with reference to FIGS. 4 (a) to 4 (g). (EHC)
The temperature of 2 is usually outside temperature (for example, 25 ° C), and (EH
The optimum operation of C) is about 350 as shown in FIG.
℃. As shown in FIG. 4B, if the ignition switch 13 is in the power ON position of the first position (so-called key switch ON) and the engine is still stopped, the line 35 ( The EHC) control signal is output from the means 308 as an ON signal. Next, if necessary, the operation of determining the voltage of the battery 15 determined by the means 303 and 304 may be ignored so that the operation steps described below are not performed.

As shown in FIG. 4C, as soon as the (EHC) control signal is turned on, the battery 15 supplies the electric power for heating the front catalyst 2. Then, when the temperature of the front catalyst 2 reaches about 50 ° C. (the required time is about 6 to 10 seconds), the ignition switch 13 then activates the starter motor 9 (as shown in FIG. 4D). It is set so that a signal for driving can be issued. With the rotation of the starter motor, the engine also starts to rotate, and as a result, the alternator 8 also starts to rotate. When the starter motor is rotated, the engine also starts to rotate, and the alternator rotation speed also gradually increases. After that, when the start of the engine is completed, the starter motor is stopped. When the starter motor is switched from ON to OFF (or, although not shown, when the engine speed detected by the rotation sensor reaches a predetermined value, the AC / DC converter control signal is transmitted via the line 32). The means 302 is switched from OFF to ON (as shown in FIG. 4F), and the state of the relay 31 is controlled according to the output signals from the means 303 and 304. If the voltage of the battery 15 is low or lower than a predetermined target value, the relay 31 is turned on and the three-phase transformer 27 and A
The charger composed of the C / DC converter operates as shown in FIG. 4 (f) to charge the 24V battery 15 via the line 29.

The charger 14 includes an AC / DC converter 28.
However, the charger 14 may be another well-known alternator or the second output of a twin rotor / twin stator alternator.

FIG. 5A is a conceptual block diagram partial functional block diagram showing the overall configuration of the second embodiment in the case of a single power supply system. First, the unexposed gas exhausted from the internal combustion engine 1 passes through the front catalyst (electrically heated catalyst) 2, the main catalyst 3, and is released to the outside air. The pre-catalyst 2 is an electrically heated catalyst (EHC) described in SAE Paper (900503), which is composed of a temperature sensor 6 for detecting the temperature of the catalyst and two terminals 7 for supplying an electric current. In the examples of the present invention, (EHC) is shown as the precatalyst, but the precatalyst is
The present invention can be applied to the case where there are a plurality of (EHC) instead of one, and the case where both the front catalyst and the main catalyst are (EHC). One of the two terminals 7 for supplying current is connected to the battery 4 and the other terminal 7 is connected to the collector of the transistor N-P-N11 of the engine control unit (ECU) 5. The engine controller 5 is not shown in FIG.
It is composed of a transistor 11 for generating (EHC) control signal, which controls switching of a relay means for ON / OFF control of current to the control circuit 12, and a control circuit 12 for receiving signal from the temperature sensor 6. As a result, the control circuit 12 generates a duty drive signal for the base of the transistor 11.
The emitter of the transistor 11 is connected to the negative terminal of the battery 4. On the other hand, the battery 4 is a conventional 12V battery connected to the alternator 8, the starter motor 9, and the electric load 10. Ignition switch 1
3 is connected between the control circuit 12 and the battery 4. Further, as shown in the lower part of FIG. 5, the control circuit 12 has a built-in function for determining whether the engine is in the cranking state. When the engine is in the cranking state, electric power is supplied to (EHC). Stop. Further, in the present embodiment, whether or not the cranking state is established is determined by the starter signal or the engine speed.

Next, the operation will be described based on the above-mentioned overall structure. When the key switch 13 is turned on, the control circuit (ECU) 5 equipped with a microcomputer uses a preset catalyst temperature set value (about 350 ° C.) as a command value,
Feedback control is performed using the signal of the temperature sensor 6 as a feedback value.
In this way, the control circuit 12 controls the duty of the base of the transistor 11 so that the temperature of the front catalyst 2 approaches the set value. (In this embodiment, an example in which duty control is performed is shown, but if the heat capacity of (EHC) is large, ON / OFF control of the relay may be simply performed.) As a result, when the temperature of the front catalyst 2 reaches 350 ° C, Transistor 1 to stop the current supply for heating precatalyst 2
1 is turned off.

The current supplied according to the ON duty of the transistor 11 flows through the battery 4, the front catalyst 2 and the transistor 11, and generates heat due to the electric resistance value of the front catalyst 2. Therefore, if the engine is started by the battery 4 and the starter motor after the precatalyst 2 is preheated, the efficiency of purifying the main catalyst gas is sufficiently high. Can be significantly removed. Further adding, when the starter motor for starting the engine is driven (E
Since the energization control for heating (HC) is stopped, the electric load of the battery 4 does not increase, so that there is no difficulty in the startability of the engine.

FIG. 5 (b) shows the control circuit 1 in FIG. 5 (a).
2 is a control system diagram in FIG. That is, in the case of the single power supply system, when the engine is in the cranking state, if the starter drive electric load and the electric heating catalyst energization electric load are simultaneously added to the power supply, the power supply voltage will drop and the engine will be difficult to start There is a problem that it will become. Therefore, the control circuit 12 has a built-in function to determine whether the engine is cranking or the engine has been started. When the engine is in the cranking state, the electric power supply to the electrically heated catalyst is stopped. Also,
In the present embodiment, whether or not the engine is in the cranking state is determined by the starter signal or the engine speed. After the engine has been started, if the temperature of the electrically heated catalyst is equal to or lower than the target heating temperature, the power supply to the electrically heated catalyst is restarted until the temperature reaches the target temperature. Also, prior to engine cranking, when the engine ignition key switch is ON, the engine is in the stopped state, and the electric heating catalyst is below the target heating temperature, it is determined that the preheating of the electric heating catalyst is OK, and the energization command is issued. The signal is output to the energization control relay (or control transistor) to preheat the electrically heated catalyst. At this time, the control time for preheat heating can be varied by a time timer that can be arbitrarily set according to the capacity of the electrically heated catalyst, the required amount of power required for heating, and the power supply capacity.

FIG. 6 is a timing chart for stopping the energization control for (EHC) heating when the engine is cranking (when the starter motor for starting the engine is driven) when the power source is one. It is a thing. That is,
When the starter switch is turned on after the ignition switch is turned on, the power supply to (EHC) is stopped and the starter switch OF is turned on.
After F, energization to (EHC) is restarted, and energization is stopped when the desired temperature is reached. If there is no starter switch signal, it may be determined from the engine speed information whether the engine is in the cranking state.

[0035]

EFFECTS OF THE INVENTION According to the present invention, even if the charge capacity of the electrically heated catalyst battery is lowered due to the catalyst heating, it can be recalled that the amount of electric power is about 4.7 kW. Since 4 is independent of the catalyst heating battery, it is possible to avoid a decrease in capacity and difficulty in starting the engine. Further, since the catalyst is heated to raise the temperature before the engine is started to improve the efficiency of purifying the gas, the amount of HC and CO emissions in the gas immediately after the engine is started can be significantly reduced. Furthermore, the consumption current can be reduced by using an independent power supply with a high voltage, which enables downsizing of component parts, overall weight reduction, and power transmission efficiency to be increased.
This has the effect of providing a compact and lightweight control device. Also, when there is only one power supply, the electric load of the power supply does not increase by stopping the energization of the electrically heated catalyst during cranking of the engine, so there is no difficulty in starting the engine and one power supply system. In case of

[Brief description of drawings]

FIG. 1 is a conceptual block diagram showing the overall configuration of a catalyst control device according to a first embodiment of the present invention.

FIG. 2 is a conceptual block diagram showing a power supply charging circuit and a heating circuit for an electrically heated catalyst proposed this time in relation to the first embodiment of the present invention.

FIG. 3 is a diagram showing a flow of a control state of the present invention.

4 (a) to (g) show a timing diagram of the operation of the control device of the present invention. In each drawing, reference numerals indicate the related numbers of each component, component, means, and the like.

FIG. 5 is a conceptual block diagram (a) showing an overall configuration of a catalyst control device according to a second embodiment of the present invention, and a conceptual block diagram of a heating circuit, a control device, and a method of an electric heating catalyst proposed this time ( It is shown in b).

FIG. 6 shows a timing diagram of the operation of the control device according to the second embodiment of the present invention.

[Explanation of symbols]

1 ... Engine, 2 ... Front catalyst (electrically heated catalyst), 3 ... Main catalyst, 4 ... Battery, 5 ... Engine control device, 6 ... Temperature sensor, 7 ... Connection terminal, 8 ... Alternator, 9 ... Starter, 10 ... Electricity Load, 11 ... Transistor, 12 ... Control circuit, 13 ... Key switch, 14 ... Charger, 15 ... Battery for heating front catalyst (electrically heated catalyst), 21 ... Warning lamp, 22 ... Ballast resistor, 23 ... Regulator, 24
... stator, 25 ... diode, 26 ... induction coil, 27 ... three-phase transformer, 28 ... AC / DC converter.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Takeshi Atako 2520 Takaba, Takata, Ibaraki Pref., Sawa Plant, Hitachi, Ltd. (72) Keiichi Masuno 2520, Takaba, Katsuta, Ibaraki Hitachi, Ltd. Factory Sawa Factory (72) Inventor Suetaro Shibukawa 2520, Takaba, Katsuta City, Ibaraki Prefecture Hitachi, Ltd. Sawa Factory (72) Inventor Shigeyuki Yoshihara 2477, Kashima Yatsu, Katsuta City, Ibaraki Prefecture 3 Hitachi Automotive Engineering Co., Ltd.

Claims (13)

[Claims] 1. An exhaust gas purifying apparatus for an engine, wherein an exhaust gas purifying catalyst for the engine is arranged in an exhaust passage of the engine, and an electrically heated catalyst that is heated by being energized with an electric current, and an electrically heated catalyst for the electrically heated catalyst. A temperature detecting means for detecting a temperature, a control means for controlling a current flowing through the electrically heated catalyst, and a control means for instructing the temperature of the electrically heated catalyst to approach a predetermined set temperature by a signal from the temperature detecting means. And an electric heating catalyst control device for purifying exhaust gas of an internal combustion engine, comprising: an electric power supply means for taking out a current supplied to the electric heating catalyst independently of an engine control power supply. 2. The electric heating according to claim 1, wherein a power supply for supplying a current to be supplied to the electric heating catalyst has a voltage equal to or higher than that of a power supply for engine control. Catalyst control device. 3. The control means for controlling the energization current of the electrically heated catalyst starts the control operation before the engine is started, according to claim 1 or claim 2. The electric heating catalyst control device described. 4. A predetermined set temperature of the electrically heated catalyst is set to 35.
The electric heating catalyst control device according to claim 1, wherein the temperature is set to 0 ° C. 5. The control means for controlling the energizing current of the electrically heated catalyst has a control circuit means which is activated by an ignition switch of an engine and is connected to a temperature detecting means for detecting the temperature of the electrically heated catalyst. The control circuit means includes a comparing means for comparing the temperature detected by the temperature detecting means with a predetermined temperature, and a switching device for controlling the supply of the energizing current of the electrically heated catalyst based on the comparison result. The electrically heated catalyst control device according to claim 1, wherein the electrically heated catalyst control device is configured. 6. The electric heating catalyst control device according to claim 5, wherein the power source means independent of the engine control power source is charged by an AC / DC converter. 7. The electric heating catalyst control device according to claim 5, wherein the power source means independent of the engine control power source is charged by an alternator. 8. The control means for controlling a current flowing through the electrically heated catalyst is an AC / DC power source means independent of the engine control power source after the engine has been started.
The electrically heated catalyst control device according to claim 5, further comprising a determination unit that determines whether or not the connection operation of the converter is started. 9. A control means for controlling a current flowing through the electrically heated catalyst comprises means for determining a voltage level of a power supply means independent of the engine control power supply, and the voltage level is higher than a predetermined voltage level. When the voltage is low, the switching device is turned on to connect the AC / DC converter to a power source means independent from the engine control power source for charging, and when the voltage level is equal to or higher than a predetermined voltage level, the switching device 6. The electric heating catalyst control device according to claim 5, wherein the AC / DC converter is turned off to disconnect the AC / DC converter from a power supply unit independent of the engine control power supply. 10. The electric heating catalyst control device according to claim 1, wherein the electric heating catalyst having a resistance element for guiding a catalyst heating current is arranged upstream of the main catalyst. 11. The electric heating catalyst control device according to claim 1, wherein the control means for controlling the energization current of the electric heating catalyst is incorporated in the engine control device. 12. A catalyst for purifying exhaust gas of an engine is arranged in an exhaust passage of the engine, and an electrically heated catalyst which is heated by being supplied with an electric current, and a temperature detection means for detecting a temperature of the electrically heated catalyst. A control means for controlling a current flowing through the electrically heated catalyst, a control means for instructing the temperature of the electrically heated catalyst to approach a predetermined set temperature by a signal from the temperature detection means, and the electrically heated catalyst. An electric heating catalyst control device for purifying exhaust gas of an internal combustion engine, comprising an electric power supply means for extracting an electric current, wherein the electric heating catalyst control device is controlled to stop energization of the electric heating catalyst during engine starting cranking. .. 13. An electrically heated catalyst control device according to claim 12, wherein it is judged whether or not the engine is under starting cranking by a starter switch signal or an engine speed.