JPH04166606A - Pre-heat control device for catalyst with heater - Google Patents

Abstract

PURPOSE:To prevent the lowering of startability by constituting an opening/ closing control means relating to a switch to connect/disconnect both a heater to heat catalyst and a power circuit in such a way that when a motor driving signal for a starter motor is received, an opening/closing output can be switched to an opening output. CONSTITUTION:In a catalytic converter 7, a heater 9 to heat catalytic converter rhodium 8 is installed on the catalytic converter rhodium 8, and this heater 9 is connected to an electric power circuit 12 equipped with a battery 13 through a switch 11. Though the switch 11 is controlled by means of a controller 3 according to its duty, in this control, according to respective data from respective sensors, the controller 3 calculates a duty ratio Du after calculating a correction value of catalytic temperature, a correction value of battery voltage and a correction value of water temperature and so on according to a prescribed map, and furthermore, at this time, a judgment on whether or not cranking is under way at present is made from an output of a cranking switch 22, and then a pulse signal Sp is outputted to the switch 11. In the case of YES, after the switch 11 is treated at a duty ratio 0, that is, by means of an opening treatment, the quantity of electric power supply to the heater 9 is cut off.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to a pre-heated catalyst with a heating element that can promote activation of the catalyst at the time of starting a cold engine.
1-Regarding the control device.

(Prior art) Vehicle exhaust system L: Exhaust gas purification device installed, for example, a three-way catalyst is equipped with both oxidation and reduction catalysts, and by maintaining the air-fuel ratio in a narrow window region including stoichiometry, the oxidation catalyst The reduction catalyst removes Co and HC from the exhaust gas, and the reduction catalyst removes N from the exhaust gas.
Each acts to convert Ox into harmless components.

However, this three-way catalyst does not exhibit catalytic activity until a predetermined activation temperature is reached. Therefore, when starting one engine cold, before starting engine warm-up.

A warm-up of the catalyst is often performed.

At this time, the catalyst is heated with a heater in order to accelerate its warm-up and achieve early activation.

This reduces the inactive operating time of the catalyst during a cold start of an engine. Efforts are being made to reduce the amount of exhaust gas generated during start-up.

(Problems to be Solved by the Invention) However, the battery of a normal vehicle is not only used for the heater for heating the catalyst, but also for driving other auxiliary equipment of the engine and each electric device of the vehicle. It is also used in

In such a case, after turning on the key, the driver starts a heater heating process that can quickly activate the catalyst. Then, cranking processing may be performed twice during this heater heating processing.

However, when the heater for heating the catalyst is being driven, the battery voltage drops, and on top of that, when the starting starter motor, which requires a large amount of electricity, is being driven, cranking cannot be performed properly. This has resulted in problems such as poor startability and early battery deterioration.

An object of the present invention is to provide a preheat control device for a catalyst equipped with a heater that can prevent deterioration in startability.

(Means for Solving the Problems) In order to achieve the above-mentioned objects, the present invention provides a heater for heating a catalyst for purifying exhaust gas of a vehicle, a power supply circuit connected to the starter motor of the vehicle, and a power supply circuit connected to the heater and the starter motor of the vehicle. It has a switch that connects and connects between the power supply circuits, and a switching control means that generates a switching output that connects and connects the switch, and the switching control means controls the starter when outputting the switching output to the switch. The present invention is characterized in that upon receiving a motor drive signal of the motor, the opening/closing output is switched to an opening force that connects the heater and the power supply circuit.

(Function) When the opening/closing control means receives a motor drive signal from the starter motor, it switches the opening/closing output to the opening output, so that it is possible to disconnect the heater from the power supply circuit.

(Example) The preheat control device for a catalyst with a heater shown in FIG. 1 is attached to an exhaust gas purification device A installed on an exhaust path 2 of a gasoline engine 1.

Here, engine 1 is an engine control unit (
The fuel supply amount is controlled by a controller (hereinafter simply referred to as a controller) 3.

An air cleaner 5 is attached to an intake passage 4 connected to the main body of the engine 1, and a catalytic converter 7 and a muffler 18 are attached to the exhaust passage 2 in the middle of an exhaust pipe 6.

A three-way catalyst 8 is disposed inside a casing 10 of the catalytic converter 7, and in particular, a heater 9 for heating the three-way catalyst 8 is attached. This heater 9 has a switch 11
A power supply circuit 12 including a battery 13 is connected via the power supply circuit 12 .

The power supply circuit 12 is made up of a wiring circuit that connects the battery 13 and other auxiliary equipment of the engine 1 and each electric device of the vehicle connected to the battery 13. In particular, a starter motor 24 that requires a large amount of electric power during engine cranking is connected to the battery 13. Note that the starter switch 23 of the starter motor 24 is connected to the drive circuit u30 of the controller 3.
Connected to 4.

In the three-way catalyst 8, a catalytic active component capable of redox treatment is adhered to the entire inner wall surface of the monolithic support in a stoichiometric atmosphere. In this three-way catalyst 8, when the exhaust gas air-fuel ratio is close to stoichiometry and at the activation temperature, HC, Go, No.
A well-known configuration is adopted that can carry out oxidation-reduction treatment and discharge harmless exhaust gas.

A secondary air pipe 14 is connected to a position upstream of the catalytic converter 7 in the exhaust pipe 6, and the intermediate pipe 14 is connected to a near compressor 15.
It is connected to the air cleaner 5 via. This compressor 15 is rotationally driven by the engine 1, and furthermore,
A built-in electromagnetic clutch is connected to the secondary air controller 16.

When this secondary air controller 16 receives a drive command signal from the controller 3, it can engage the electromagnetic clutch, drive the compressor 15, and supply secondary air to the exhaust path 6.

Note that reference numeral 17 in FIG. 1 indicates a catalyst temperature sensor that outputs internal temperature information of the three-way catalyst 8. Furthermore, code 19.2
0.21 and 22 respectively indicate a doorknob switch, a water temperature sensor, an intake temperature sensor, and a cranking switch in this order.

Here, the doorknob switch 19 constitutes a driving start prediction signal generating means that detects when the driver begins to get into the vehicle and generates a preheat-on signal S. This switch 19 is arranged opposite to a doorknob of a driver's seat of a vehicle (not shown), and is configured to issue a preheat-on signal S when the doorknob is opened.

The water temperature sensor 20 can output the temperature information of the cooling water of the engine 1, the intake temperature sensor 21 can output the air temperature information in the air cleaner 5, and the cranking switch 22 is configured by a crank angle signal generator in the distributor (not shown). ing.

As shown in FIG. 3, the above-mentioned switch 11 is formed by a CMOS that is a combination of a P-channel MOSQL and an N-channel MO5Q2. A drive output P having a predetermined duty ratio is input from the controller 3 to the input terminal T1, and a heater 9 is connected to the output terminal T2. Then, the source of P channel MOS QL is connected to ground, and the source of N channel MOS Q2 is connected to battery 13.
(7) Connected to the 12 V terminal.

As a result, when the pulse signal Sp as a duty ratio signal is input from the controller 3 to the input terminal T1, the duty ratio is changed to switch the potential from ov to 12■ as shown in FIG. A driving force Du having a duty ratio of about 60% (a waveform is shown) is supplied to the heater 9.

The switch 11 of such a CMO 5 has relatively low power consumption (
It works effectively as the switch 11 of the power supply circuit 12, which requires relatively large heater power for early activation.

The main part of the controller 3 is composed of a microcomputer, and in particular receives pressure information from the above-mentioned sensors,
An input/output circuit 301 that takes in the information in a timely manner or outputs a pulse signal Sp or a drive command signal to the secondary air controller 16, and an on-output to the starter switch 23 in response to the drive command signal from the input/output circuit 301. The drive circuit 304 that generates the signal, the preheat control program shown in FIG. 5, and the preheat control program shown in FIGS.
The control circuit 302 includes a storage circuit 302 in which duty ratio correction value maps, characteristic values, etc. are written, and a control circuit 303 that calculates control values according to a control program.

Here, the 1 calculation map for the catalyst temperature correction value in Fig. 4(a) is set to 1 when the catalyst temperature is below 350@, and
In the change range α up to °, the value gradually decreases from 1 to 0,
The heater 9 is set to be turned off when the temperature exceeds 45 degrees, indicating that activation is complete.

In the on-time correction value map shown in Figure 4(b), 2 is set to 1 as the correction value until 30 seconds have elapsed since the heater was turned on, and 2 is gradually set to 1 in the change range α up to 60 seconds. is lowered from 1 to O, and the heater 9 is set to be turned off after 60 seconds have elapsed to protect the battery.

The 3-calculation map for the battery voltage correction value in Figure 4(c) shows that when the battery voltage ■ is 12°C or higher, the correction value is set to 3, and in the variation range α between 12 and 10V, it corresponds to the voltage drop. Then, the value is gradually lowered from 1 to O, and the heater 9 is set to be turned off at 10 V or less to protect the battery.

The 4 calculation map for the water temperature correction value in Figure 4 (d) indicates that the water temperature is 0°C.
In the above, the correction value 4 is set to 1, and in the variation range α between 0℃ and -10℃, the value is gradually lowered from 1 to O according to the temperature drop, and below -10℃, the battery protection is Therefore, the heater 9 is set to be turned off.

The 5 calculation map for the intake temperature correction value in Fig. 4(e) sets the correction value of 5 to 1 when the intake temperature is 0°C or higher, and from 0°C to -10°C.
In the range of change α between
The heater 9 is set to be turned off at temperatures below -10° C. to protect the battery.

The controller 3 has at least a function as a preheat control means.

This controller 3 performs a main routine for a well-known engine operation control process by turning on the engine key (not shown).
Other separate processing is executed, and the main routine and others are stopped when the key is turned off. During key-off, preheat control processing is executed when the preheat-on signal S is input.

When we enter this preheat control routine, first.

Start a timer, capture each detection information from each sensor, and store it in a predetermined area.

When step a3 is reached, the process proceeds to step a4 until the timer reaches a predetermined elapsed time (set to 5 seconds here). Here, based on each data, the catalyst temperature correction value is 1, the on-time correction value is 2, the battery voltage correction value is 3, and the water temperature correction value is 4. Add 5 to the intake temperature correction value in a predetermined map (fourth
Figures (a), (b), (c), (d), (e
) is calculated based on each duty ratio correction value map (see each duty ratio correction value map). Then, the duty ratio Du is calculated based on the formula below and stored at the address Du.

Du=KIXK2XK3XK4XK5 Here, the duty ratio Du and battery voltage V
A current value I corresponding to the current value is calculated based on a predetermined map and stored in the address area.

When step a5 is reached, it is determined whether the current caution is zero or not, and if it is not zero, the process proceeds to step a6 and a flag H is set.

When step a7 is reached, it is determined whether or not cranking is currently being performed based on the output signal of the cranking switch 22. That is, at this point, it is determined whether the driver has already entered the vehicle and turned on the cranking switch after turning on the key. Step a8 while not cranking
Then, the pulse signal S of the duty ratio of the address DU is
p is output to the switch 11, the switch emits the drive output P, and the process returns to step a2.

As a result, the heater 9 has a predetermined duty ratio Du.
Electricity is supplied with current value regulation.

For example, if the catalyst temperature is 350° C. or lower, the heater on time is less than 30 seconds, the battery voltage is 12 V or higher, the water temperature is 0° C. or higher, and the intake air temperature is 0° C. or higher, the catalyst temperature correction value K1. 2 for on time correction value, 3 for battery voltage correction value
, 4 for the water temperature correction value, and 5 for the intake temperature correction value are all 1, the denial ratio becomes Du = 1, the switch is 100% open, 100% of power is supplied from the power supply circuit 12, and the catalyst is activated early. Activation is achieved most efficiently. In particular, heater 9
The driving of the vehicle starts before the driver completes getting into the vehicle, and the driver has a relatively short waiting time during preheating, so that the driver does not feel any pain due to the prolonged waiting time.

On the other hand, if the calculation range of each correction value is in the change range α,
Each correction value decreases, and the duty ratio Du decreases by 10
Change between 0% and 0%.

In this case, the amount of power supplied from the power supply circuit 12 is reduced, and this process not only protects the battery, but also prolongs the oscillation time of the heater 9 as much as possible to promote activation of the catalyst.

On the other hand, if one of the correction values becomes zero in step a4, the duty ratio Du becomes zero.

In this case, the process proceeds to step a10 at step a5, where flag H is cleared, and step a8 is reached. Then, the power supply from the power supply circuit 12 is cut off, and this process only protects the battery. In such a case, a preheat process for catalyst activation is performed in the main routine.

On the other hand, if cranking has been performed in step a7, the process proceeds to step a9, and the value of the address Du calculated in step a4 is rewritten to zero. The process then proceeds to step a8, where the switch 11 is opened at a duty ratio of O5, thereby cutting off the power supply from the power supply circuit I2 to the heater 9.

By such processing, a voltage drop occurs in the eight-wheel drive unit 13 when the heater is turned on, which allows accurate cranking and prevents deterioration of startability. That is, here, the heater is turned off in order to give priority to cranking.

The control sequence is repeated again and reaches step a3. At this time, if 5 seconds have already elapsed from the start, the process proceeds to step all. Here, if the current caution is not zero and the flag H is 1, the process proceeds to step a4, but if the flag H is zero, the preheat control is ended and the process returns to the main routine.

The controller 3 is configured to issue a drive output to the secondary air controller I6 when the catalyst temperature detected by the catalyst temperature sensor 17 reaches a predetermined value. As a result, when the secondary air controller 16 receives a drive command signal from the controller 3, it engages the electromagnetic clutch, drives the compressor 15, supplies secondary air to the exhaust path 6, and performs exhaust gas purification processing. be able to.

In the above-mentioned place, as the operation start prediction signal generation means,
Although the door knob switch 19 has been described, instead of this, a switch may be attached to the door key cylinder of the driver's seat door, and the switch may be configured to output the preheat-on signal S by inserting the key, and further, It is also possible to install a keyless entry system on the driver's door and configure it so that the unlock signal can be obtained from a remote use card.

(Effects of the Invention) As described above, the present invention has the following advantages. Since the opening/closing control means can cut off the connection between the heater and the power supply circuit in accordance with the motor drive signal of the starter motor, cranking can be performed accurately with priority over heater drive, and deterioration in startability can be prevented.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of a preheat control device for a catalyst with a heater as an embodiment of the present invention, Fig. 2 is a waveform diagram of the drive output P output from the switch of the above device, and Fig. 3 is a waveform diagram of the drive output P of the same device. Switch circuit diagram, Figure 4 (a), (b), (c), (
d) and (e) are characteristic diagrams of each duty ratio correction value map built into the controller of the above device, and FIG. 5 is a flowchart of a preheat control program executed by the controller of the above device. DESCRIPTION OF SYMBOLS 1... Engine, 2... Exhaust path, 3... Controller, 8... Three-way catalyst, 9... Heater, 11...
Switch, 12... Power supply circuit, 13... Battery, 2
4...Starter motor. Agent Toru Kabayama). L knee:': =5. %

Claims (1)

[Claims] a power supply circuit connected to a heater that heats a catalyst for purifying exhaust gas of a vehicle and a starter motor of the vehicle;
It has a switch that connects and disconnects between the heater and the power supply circuit, and a switching control means that generates a switching output that connects and connects the switch, and the switching control means outputs the switching output to the switch. . A preheat control device for a catalyst with a heater, characterized in that upon receiving a motor drive signal of the starter motor, the opening/closing output is switched to an opening output that cuts off the connection between the heater and the power supply circuit.