JP3216144B2 - Operation control method of vehicle equipped with heater-equipped catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst with a heater, which can achieve both practicality and purification of exhaust gas by selectively using an internal combustion engine and an electric motor driven by a storage battery as a drive source of a vehicle. The present invention relates to a driving control method for a vehicle mounted on the vehicle.

[0002]

2. Description of the Related Art In recent years, regulations on harmful components in exhaust gas emitted from vehicles equipped with an internal combustion engine have been stricter from the viewpoint of environmental problems, and many new technologies have been researched and developed in order to comply with the regulations. ing. One technology is a catalyst with a heater, and this technology aims to reduce the running state when the catalyst is inactive and reduce the emission of harmful components by actively heating the catalyst provided in the middle of the exhaust passage. Things.

[0003]

In a vehicle equipped with a conventional catalyst with a heater, even if heating of the catalyst heater is performed simultaneously with the start of the engine, the catalyst is not immediately activated immediately after the start of the engine. Until the catalyst reaches its activation temperature, it is impossible to detoxify harmful components in the exhaust gas from the engine.

For this reason, a method has been proposed in which the catalyst heater is operated for a predetermined time before the engine is started, and the engine is started when the catalyst has reached its activation temperature. Therefore, it is necessary to wait until the vehicle can run, which is problematic in an emergency or the like, and is inferior in practical use.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heater capable of realizing both practicality in emergency situations and purifying exhaust gas by using an internal combustion engine and an electric motor driven by a storage battery as driving sources for a vehicle. It is an object of the present invention to provide an operation control method of a vehicle equipped with a catalyst with a load.

[0006]

A method of operating a vehicle equipped with a catalyst with a heater according to the present invention is provided at an intermediate position in an exhaust passage connected to the internal combustion engine and the electric motor as a driving source of the vehicle. In a vehicle having a catalyst for purifying exhaust gas discharged from a lever internal combustion engine and a heater for raising the catalyst to its activation temperature, the start of the internal combustion engine is suppressed until the catalyst is activated. The vehicle is driven by the electric motor, and the electric motor is stopped after the catalyst is activated.
The internal combustion engine is started and the vehicle is driven by the internal combustion engine.

[0007]

In a normal state in which the catalyst is activated, the vehicle is driven by using the internal combustion engine as a power source as in a conventional vehicle, and the operation of the electric motor is stopped during this time.

[0008] In a situation such as immediately after a cold start or downhill, where the catalyst is not activated and most of the harmful components occupying the exhaust gas may be directly discharged, the internal combustion engine is stopped. The vehicle is driven by an electric motor, and during this time, the catalyst is heated by a heater.

Then, after the catalyst is activated, the electric motor is stopped and the internal combustion engine is started to return to a normal operation state.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1 showing the concept of an operation control method for a vehicle equipped with a catalyst with a heater according to the present invention, an output shaft (not shown) of an engine 12 whose operation is controlled by an engine control unit 11 is shown. Has a clutch control unit 1
3, an engine clutch 14 whose operation is controlled.
Is connected. An output shaft (not shown) of an electric motor 16 provided in parallel with the engine 12 and supplied with current from a storage battery (not shown) via a motor control unit 15 is connected to the clutch control unit 13 to operate the motor. A controlled motor clutch 17 is connected.

The engine control unit 11 includes an engine 12
Sensors for maintaining good operation of the engine, such as engines
12 , an engine speed sensor 18 for detecting the rotation speed of a crankshaft (not shown), an accelerator opening sensor 19 for detecting the depression amount of an accelerator pedal (not shown) operated by the driver, or a vehicle speed for detecting the traveling speed of the vehicle A sensor 20, a throttle opening sensor 21 for detecting the opening of a throttle valve (not shown), and the like are connected, and detection signals from these various sensors 18 to 21 are output.

In this embodiment, Japanese Patent Application Laid-Open No. 2-201006
As disclosed in Japanese Unexamined Patent Publication No. 1 (1994), the opening / closing operation of the throttle valve is performed by an actuator (not shown) separately from the depression amount of the accelerator pedal, and the target vehicle speed of the vehicle is adjusted by the gear position of the transmission 28 and the accelerator pedal. The throttle valve is opened and closed by the actuator in accordance with the setting.

The motor control unit 15 is connected to a motor speed sensor 22 which is mounted on the electric motor 16 and detects the speed of the output shaft of the electric motor 16, and outputs a detection signal from the motor speed sensor 22. It has become.

Further, the clutch control unit 13 has an output shaft 2 mounted on an engine clutch 14.
Engine speed sensor 24 for detecting engine speed 3
And a motor clutch rotational speed sensor 26 that is assembled to the motor clutch 17 and detects the rotational speed of the output shaft 25, respectively, and the detection signals from these sensors 24 and 26 are output. ing.

An endless power transmission belt 27 is wound around an output shaft 23 of the engine clutch 14 and an output shaft 25 of the motor clutch 17 via sprockets (not shown), and an input shaft 29 of a transmission 28 is provided. The engine clutch 14 is connected to the output shaft 23 side.

In this embodiment, as the engine clutch 14 and the motor clutch 17, an electromagnetic clutch capable of adjusting the transmission rate of the driving force to the input shaft 29 of the transmission 28 by the amount of energization is employed. 24,2
The clutch control unit 13 sets the energization amount based on the detection signal from the motor 6 and the driving state of the vehicle, and outputs the amount to the engine clutch 14 and the motor clutch 17, respectively.

The transmission 15 of this embodiment employs a type in which the shift position and the select position can be switched by a plurality of actuators based on the position of a shift lever (not shown) operated by the driver. The operation of these actuators is controlled by the transmission control unit 30.

For this reason, the transmission control unit 30 has a gear position sensor 3 mounted on the transmission 15 for detecting the current gear position (hereinafter referred to as a gear position).
1 and a shift lever position sensor 32 for detecting the position of the shift lever are connected.
1, and a detection signal from the shift lever position sensor 32 or the like is output.

A catalyst 34 with a heater is interposed in the middle of an exhaust pipe 33 serving as a passage for exhaust gas discharged from the engine 12. The catalyst 34 with a heater detects the temperature of the catalyst 34 with a heater. A temperature sensor 35 is provided. The catalyst temperature sensor 35 is connected to a catalyst control unit 36 for controlling on / off of energization of a catalyst with heater 34 to a catalyst heater (not shown). The detection signal from the catalyst temperature sensor 35 is
Is output to

The engine control unit 11 and the other control units 13, 15, 30, and 36 are electrically connected to each other via a signal cable 37 in order to exchange necessary information with each other. , Each control unit 1
Control information from 1, 13, 15, 30, and 36 are controlled via control cables 38, respectively, and control the engine 12, engine clutch 14, electric motor 16, motor clutch 17, transmission 28, catalyst with heater 34.

Therefore, when the catalyst with heater 34 is in an inactive state, it is difficult to satisfactorily purify the exhaust gas from the engine 12. Therefore, the operation of the engine 12 is stopped and the electric motor is controlled by the motor control unit 15. 16 so that the target vehicle speed V _O is set based on the detection signal output from the accelerator opening degree sensor 19 in accordance with the amount of depression of the accelerator pedal by the driver. Control properly.

In this state, the crankshaft of the engine 12 and the input shaft 29 of the transmission 28 are separated by the engine clutch 14, and the driving force of the electric motor 16 is transmitted via the motor clutch 17 to the power transmission belt 27. Is transmitted to the input shaft 29 of the transmission 28.

However, since the exhaust gas from the engine 12 can be satisfactorily purified in a state where the catalyst with heater 34 is activated, the operation of the electric motor 16 is stopped and the engine control unit 15 controls the engine 12. Activate,
The opening degree of the throttle valve, the fuel supply amount and the ignition timing are set so that the target vehicle speed V _O is set based on the detection signal output from the accelerator opening degree sensor 19 in accordance with the amount of depression of the accelerator pedal by the driver. Are appropriately set to control the operation of the engine 12.

In this state, the output shaft of the electric motor 16 and the output shaft 29 of the transmission 28 are separated by the motor clutch 17, and the driving force from the crankshaft of the engine 12 is transmitted via the engine clutch 14. The power is transmitted to the input shaft 29 of the transmission 28, and the power transmission belt 27 continues to idle.

Note that the target vehicle speed V of the vehicle in this embodiment is
_O is read from a map as shown in FIG. 2 which is set based on the accelerator opening θ corresponding to the depression amount of the accelerator pedal.

As shown in FIGS. 3 and 4 showing the flow of processing according to the present embodiment, at S1, one of the engine 12 and the electric motor 16 is selected as a drive source of the vehicle. determining performs driving source selection process to be described later, and then whether or not it is set driving source operation flag F _D indicating that driving source selected in step of S1 is being operated in S2.

[0027] If it is determined as a driving source operation flag F _D is determined in step S2 is set, i.e., S1 drive source selected in step is in operation, S3
After performing a drive control process to be described later for controlling the drive source, it is determined in S4 whether or not a drive source switch such as an ignition key is turned off.

If it is determined in step S4 that the drive source switch is off, that is, if a stop command for the drive source has been issued, it is determined in step S5 that the electric motor 16 is being used as a drive source. determining selection flag F _M is whether or not it is reset.

[0029] If it is determined that the motor selection flag F _M is determined in step S5 is reset, i.e. the engine 12 as a driving source of the vehicle is selected, stopping the operation of the engine 12 at S6 after the engine stop process of stopping supply of the fuel it is performed in order to reset the driving source operation flag F _D at S7.

[0030] When the driving source operation flag F _D is determined in step S2 is not set, that is, the drive source selected at S1 in step is determined to be stopped,
In S8, it is determined whether the drive source switch is on.

The drive source switches at this step S8 is on, that is, if it is determined that there has been start command of the drive source, determines whether the motor selection flag F _M is reset in S9 I do.

[0032] If it is determined that the motor selection flag F _M is determined in step S9, is reset, i.e. the engine 12 as a driving source of the vehicle is selected, S10
After the engine start process such as the start of fuel supply to start the operation of the engine 12 is performed in S11, it is determined in S11 whether the start of the engine 12 is completed. In this case, based on the detection signal from the engine speed sensor 18 in the present embodiment, it is determined that the start of the engine 12 is completed when the engine speed N _E has a preset value or more.

[0033] If it is determined that the start of the engine 12 at this step S11 is completed, sets the driving source operation flag F _D at S12, the process proceeds to step of the S4, the S11 If it is determined in step that the engine 12 has not been started, the process directly proceeds to step S4 to determine whether the drive source switch is off.

On the other hand, if it is determined in step S8 that the drive source switch is not on, that is, there is no drive source start command, the process proceeds to step S4 to determine whether the drive source switch is off. Is determined.

[0035] Further, the motor selection flag F _M at step S9, not reset, that is, if it is determined that the electric motor 16 is selected as a drive source of the vehicle, the electric motor 16 in S13 After the motor start process such as energization of the electric motor 16 is performed in order to start the operation, it is determined in S14 whether the start of the electric motor 16 has been completed. In this case, in the present embodiment, the end of the activation of the electric motor 16 is determined based on the detection of disconnection of the electric motor 16 and the like.

In step S14, the electric motor 16
If it is determined that the start of the process has been completed,
Set the transition to the driving source operation flag F _D step of, when it is determined that the start of the electric motor 16 does not end in at this step S14, the drive source switch goes directly to step S4 It is determined whether or not is turned off.

If it is determined in step S4 that the drive source switch is not off, the process proceeds to step S1 to perform drive source selection processing.

[0038] The motor selection flag F _M is not reset in step of the S5, that is, when the electric motor 16 is determined to have been selected as the drive source of the vehicle, the electric motor 16 at S15 after operation performed motor stop processing such energization blockade on the electric motor 16 to stop the, resetting the driving source operation flag F _D proceeds to the step of the S7.

As shown in FIG. 5 showing the flow of the drive source selection process in the step S1, the output signal O from the catalyst temperature sensor 35 is set in advance as the activation temperature of the catalyst with heater 34 at C1. the first determining whether the threshold O _H greater than the output signal O from the catalyst temperature sensor 35 is determined in step C1 is greater than the first threshold value O _H, i.e. with a heater catalyst 34 is active When it is determined that the engine 12 has been activated, the energization of the heater of the heater-equipped catalyst 34 is stopped at C2, and an engine selection process to be described later for selecting the engine 12 as a drive source is performed at C3. S
Go to step 2.

In the step C1, the catalyst temperature sensor 3
5 is the first threshold O _HDetermined to be
Output from the catalyst temperature sensor 35 at C4
Signal O is preset as the activation temperature of catalyst 34 with heater
Second threshold O_LIs determined to be smaller than
Output signal from the catalyst temperature sensor 35 at the step C4
O is the second threshold O_LSmaller, ie catalyst with heater
If it is determined that 34 is not activated, at C5
The heater of the catalyst with heater 34 is energized, and C6
A motor, which will be described later, selects the electric motor 16 as a drive source.
After performing the data selection process, the process proceeds to step S2 shown in FIG.
Run.

On the other hand, when the output signal O from the catalyst temperature sensor 35 is determined in step C4 has a value greater than the second threshold value O _L is used as a drive source in the currently selected at C7 Then, the process proceeds to step S2 shown in FIG.

As described above, in this embodiment, the activation temperature of the catalyst with heater 34 is set to the first threshold value O _H and the first threshold value O _H
Set the second threshold value O _L is lower than the, by variation of the driving torque and the engine 12 and the electric motor 16 as a driving source due to the frequent switching, taking into consideration not to feel uncomfortable occupant However, it is of course possible to select the drive source with one threshold.

As shown in FIG. 6 showing the flow of engine selection process in step C3 described above, it determines whether or not the motor selection flag F _M is set at E1, the E
Motor selection flag F _M is set at 1 in step, i.e. if the engine 12 is determined to be stopped at this time performs the starting process of the engine 12 of the supply start of the fuel at E2, Next, at E3, it is determined whether or not the start of the engine 12 has been completed.

If it is determined in step E3 that the start of the engine 12 has been completed, the engine clutch 14 is energized in E4 and the output shaft of the engine 12 is connected to the output shaft of the engine 12 via the engine clutch 14. The input shaft 29 of the transmission 28 is connected, and further, the energization of the motor clutch 17 is released at E5, and the output shaft side of the electric motor 16 and the input shaft of the transmission 28 are disconnected.

Thereafter, at E6, the electric motor 16 is
To stop the operation of the electric motor 16 such as shutting off the current
Motor stop control, and then the motor selection
F _MAfter resetting, the step S2 shown in FIG.
Transition.

[0046] The motor selection flag F _M in the step of E1 has not been set, ie institutions at the moment 12
If it is determined that the engine 12 is operating, or if it is determined in E3 that the start of the engine 12 has not been completed, the process directly proceeds to step S2 shown in FIG.

Meanwhile, it is determined whether, as shown in FIG. 7 showing a flow of the motor selection process in step C6 described above, the motor selection flag F _M at M1 is reset, steps of the M1 If it is determined that the motor selection flag F _M has been reset in step, that is, if the engine 12 is operating, a motor start-up process such as starting energization of the electric motor 16 is performed in M2, and then M3 It is determined whether or not the activation of the electric motor 16 has been completed.

If it is determined in step M3 that the activation of the electric motor 16 has been completed, the motor clutch 17 is energized in M4 and the motor clutch 1 is turned on.
7, the output shaft of the electric motor 16 and the input shaft 29 of the transmission 28 are connected by the power transmission belt 27 via the motor clutch 17, and the engine clutch 14 is connected at M5.
To the output shaft side of the engine 12 and the transmission 2
8 is disconnected from the input shaft 29.

[0049] Thereafter, performs the engine stop processing for the stop of the operation of the engine 12 at M6, then after setting the motor selection flag F _M, the process proceeds to S2 of the step shown in FIG.

[0050] The motor selection flag F _M at step M1 has not been reset, i.e. or when the engine 12 is determined to be in operation, when not completed starting the electric motor 16 at M3 If it is determined, the process directly proceeds to step S2 shown in FIG.

As shown in FIG. 8 showing the flow of the drive control process in the step S3, first, at D1, the accelerator operation is performed based on the output signal from the accelerator opening sensor 19 corresponding to the amount of depression of the accelerator pedal by the driver. The opening degree θ _A is detected, and the target vehicle speed V _O corresponding to the accelerator opening degree θ _A is read from a map as shown in FIG.

In this embodiment, the accelerator opening θ _A is calculated using the previously calculated accelerator opening θ _{A (n-1)} and the filter constant K as a method for calculating the accelerator opening θ _A as follows. _{θ A = K · θ A (} n-1) + (1-K) · P where, P is an output from an accelerator opening sensor 19.

Next, at D3, the current gear position of the transmission 16 is detected based on the output signal from the gear position sensor 31, and the engine 12 or the electric power source as a drive source is determined based on the gear position and the target vehicle speed V _O. In this embodiment, the target rotation speed N _O of the motor 16 is calculated at D4 by the following equation. N _o = V _o · 1000 · i / 60 · 2 · π · R where i is the total reduction ratio of the drive system, π is the pi, and R is the radius of a wheel (not shown).

Then, at D5, the motor selection flag F _M
There is judged whether it is reset, when the motor selection flag F _M is determined in step D5 is reset, i.e. the engine 12 is determined to have been selected as a drive source, at D6 detecting the engine speed N _E based on the output signal from the engine speed sensor 18, a decision is made as to whether the engine speed N _E is larger than the target rotational speed N _O at D7.

[0055] If the step in the engine speed N _E of the D7 has a value greater than the target rotational speed N _O, i.e. the engine speed N _E is too high, the operation of the actuator to close the throttle valve Is controlled to bring the engine speed N _E close to the target speed N _O, and then the process proceeds to the step S4 shown in FIG.

[0056] If it is determined that the motor selection flag F _M at step D5 is not reset, that is, the electric motor 16 is selected as the driving source, D9
At the detected rotational speed N _M of the electric motor 16 by an output signal from the motor rotation sensor 22, a decision is made as to whether the motor rotation speed N _M at D10 is larger than the target rotational speed N _O.

In the step D10, the motor speed N
_M is larger than the target rotation speed N _O , that is, the motor rotation speed N _M
After within If it is judged to be too high, which close as a predetermined amount set the motor drive current advance by reducing the motor rotational speed N _M to the target rotational speed N _O at D11, S4 step shown in FIG. 4 Move to Moreover, less than the motor rotational speed N _M is the target rotational speed N _O is determined in step D10, i.e., when it is determined that the motor rotational speed N _M is too low, a preset motor drive current at D12 constant After increasing the motor rotation speed N _M to the target rotation speed N _O by increasing the amount by an amount, the process proceeds to step S4 shown in FIG.

Meanwhile, the smaller than D7 step in the engine speed N _E of the target rotational speed N _O, if that is the engine rotational speed N _E is determined to be too low, so that its throttle valve is opened after close the engine speed N _E at the target rotational speed N _O by controlling the operation of the actuator, moves to step S4 shown in FIG.

In this embodiment, the engine 12 as a driving source is
Although the electric motor 16 and the electric motor 16 are arranged in parallel, it is of course possible to arrange an electric motor in series between the output shaft 23 of the engine clutch 14 and the input shaft 29 of the transmission 28. In this case, the rotor of the electric motor rotates integrally with the engine even while the engine is operating, so it can be used as a flywheel. It is desirable to use a type having a small inertial mass only of an iron core not incorporated. Institution 1
When the motor 2 and the electric motor 16 are connected in series, it is not necessary to use the motor clutch 17 and the power transmission belt 27, and the process of step E5 shown in FIG. Steps and the like may be omitted.

In this embodiment, the target vehicle speed of the vehicle is set based on the accelerator opening.
As disclosed in Japanese Patent Publication No. 02058, the target drive torque of the drive source may be set based on the accelerator opening and the rate of change of the accelerator opening.

[0061]

According to the method for controlling the operation of a vehicle equipped with a heater-equipped catalyst according to the present invention, the vehicle is driven by an electric motor without operating the internal combustion engine when the catalyst is in an inactive state. Since no exhaust gas is generated, emission of harmful components can be completely eliminated. In addition, since the internal combustion engine is operated only when the catalyst is activated, most of the harmful components in the exhaust gas during the operation of the internal combustion engine are detoxified by the catalyst, and the harmful components as a whole are reduced. Can be significantly reduced.

On the other hand, since the running conditions of the electric motor are limited to the inactive period of the catalyst, the capacity of the electric motor and the capacity of the storage battery for supplying power to the electric motor must be reduced as compared with a normal electric vehicle. Is possible.

Furthermore, since the vehicle can be started immediately by the electric motor even in the cold state, it is very advantageous in terms of practicality in an emergency or the like.

[Brief description of the drawings]

FIG. 1 is a control block diagram illustrating an example of a vehicle equipped with a catalyst with a heater capable of implementing an operation control method according to the present invention.

FIG. 2 is a map showing a relationship between an accelerator opening and a target vehicle speed according to the embodiment.

FIG. 3 is a flowchart showing a flow of processing of an operation control method according to the present embodiment together with FIG.

FIG. 4 is a flowchart showing a flow of processing of an operation control method according to the present embodiment together with FIG.

FIG. 5 is a flowchart illustrating a flow of a drive source selection process in FIG. 3;

FIG. 6 is a flowchart showing a flow of an engine selection process in FIG. 5;

FIG. 7 is a flowchart illustrating a flow of a motor selection process in FIG. 5;

FIG. 8 is a flowchart illustrating a flow of a drive control process in FIG. 3;

[Explanation of symbols]

11 is an engine control unit, 12 is an engine, 13 is a clutch control unit, 14 is an engine clutch, 15 is a motor control unit, 16 is an electric motor, 17 is a motor clutch, 18 is an engine speed sensor, and 19 is an accelerator opening. Degree sensor, 20 is a vehicle speed sensor, 21 is a throttle opening degree sensor,
22 is a motor speed sensor, 24 is an engine clutch speed sensor, 26 is a motor clutch speed sensor, 27
Is a power transmission belt, 28 is a transmission, 30 is a transmission control unit, 31 is a gear position sensor, 32 is a shift lever position sensor, 34 is a catalyst with a heater, 35 is a catalyst temperature sensor, 36 is a catalyst control unit, and 37 is a catalyst control unit. Signal cable, 3
8 is a control cable.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // B60K 25/04 F02N 11/04 D F02N 11/04 B60K 9/00 ZHVE (56) References JP-A-49-22376 ( JP, A) JP-A-49-86714 (JP, A) JP-A-58-72632 (JP, A) JP-B-56-17724 (JP, Y2) (58) Fields studied (Int. Cl. ⁷ , (DB name) F02D 29/02 B60K 6/02 B60K 17/04 F01N 3/20 F01N 3/24 B60K 25/04 F02N 11/04

Claims (1)

(57) [Claims] An internal combustion engine and an electric motor as driving sources of a vehicle, a catalyst provided in the middle of an exhaust passage connected to the internal combustion engine for purifying exhaust gas discharged from the internal combustion engine, A vehicle having a heater that raises the catalyst to its activation temperature, wherein starting of the internal combustion engine is suppressed until the catalyst is activated, and the vehicle is driven by the electric motor. When the motor is stopped,
Wherein the internal combustion engine is started and the vehicle is run by the internal combustion engine.