JPH04274926A - Method of controlling operation of vehicle where catalyst fitted with heater is mounted - Google Patents

Abstract

PURPOSE:To provide a method of controlling the operation of a vehicle, on which a catalyst fitted with a heater is mounted and which enables the compatibility of the practicability and the cleaning of exhaust gas, by using an internal combustion engine and an electric motor driven by a storage battery each in its proper way as the driving source of a vehicle. CONSTITUTION:This method has a catalyst 34 fitted with a heater, which is provided in the middle of the exhaust passage 33 connected to an internal combustion engine 12 and cleans the exhaust gas exhausted from this internal combustion engine 12, and the vehicle is made to run by an electric motor 16 separately from the internal combustion engine 12, and until the catalyst 34 fitted with a heater is activated, the internal combustion engine 12 is not started, and the vehicle is made to run by the electric motor 16, and after the catalyst 34 fitted with a heater is activated, the electric motor 16 is stopped, and also the internal combustion engine 12 is started, and the vehicle is made to run by this internal combustion engine 12.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides a catalyst with a heater that achieves both practicality and purification of exhaust gas by selectively using an internal combustion engine or an electric motor driven by a storage battery as a drive source for a vehicle. This invention relates to a driving control method for a vehicle equipped with the vehicle.

0002

[Background Art] In recent years, regulations on harmful components in exhaust gas emitted from vehicles equipped with internal combustion engines have become stricter from the perspective of environmental issues, and many new technologies have been researched and developed to comply with these regulations. ing. One such technology is a heated catalyst, which actively heats a catalyst placed in the middle of the exhaust passage, thereby reducing the number of times the vehicle is running with the catalyst inactive and reducing the amount of harmful components emitted. It is something.

0003

[Problems to be Solved by the Invention] In vehicles equipped with conventional heater-equipped catalysts, even if the catalyst heater is heated at the same time as the engine starts, the catalyst is not activated immediately after the engine starts. It is not possible to detoxify harmful components present in the exhaust gas from the engine until the catalyst reaches its activation temperature.

[0004] For this reason, a method has been proposed in which the catalyst heater is operated for a predetermined period of time before starting the engine, and the engine is started when the catalyst reaches its activation temperature. In this case, it is necessary to wait until the vehicle is ready to run, which poses problems in emergencies and is less practical.

[0005]

[Object of the Invention] The present invention provides a heater that achieves both practicality and purification of exhaust gas, especially in emergencies, by selectively using an internal combustion engine and an electric motor driven by a storage battery as a drive source for a vehicle. The purpose of the present invention is to provide a driving control method for a vehicle equipped with a catalyst.

[0006]

[Means for Solving the Problems] A method for controlling the operation of a vehicle equipped with a catalyst equipped with a heater according to the present invention is provided in the middle of an exhaust passage connected to an internal combustion engine to purify exhaust gas discharged from the internal combustion engine. In a vehicle having a catalyst for activating the catalyst and a heater for raising the catalyst to its activation temperature, the vehicle can be driven by an electric motor separate from the internal combustion engine, and the internal combustion engine is operated until the catalyst is activated. The vehicle is driven by the electric motor without starting the engine, and after the catalyst is activated, the electric motor is stopped and the internal combustion engine is started, and the vehicle is driven by the internal combustion engine. It is characterized by the fact that

[0007]

[Operation] In a normal state in which the catalyst is activated, the vehicle is driven using the internal combustion engine as the power source, similar to conventional vehicles, and during this period, the electric motor is stopped.

[0008] In situations where there is a possibility that most of the harmful components in the exhaust gas will be emitted as they are because the catalyst is not activated, such as immediately after a cold start or when going down a slope, the internal combustion engine should be stopped. The vehicle is driven by the electric motor, and during this time the catalyst is heated by the heater.

After the catalyst is activated, the electric motor is stopped and the internal combustion engine is started to return to normal operating conditions.

0010

[Embodiment] As shown in FIG. 1, which shows the concept of an embodiment of the driving control method for a vehicle equipped with a heater-equipped catalyst 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. Clutch control unit 1
an engine clutch 14 whose operation is controlled by being connected to
is connected. Further, an output shaft (not shown) of an electric motor 16, which is provided in parallel with the engine 12 and to which current from a storage battery (not shown) is supplied via a motor control unit 15, is connected to the clutch control unit 13 to control its operation. A controlled motor clutch 17 is connected.

The engine control unit 11 includes an engine 11
various sensors for maintaining good operation, such as an engine rotation speed sensor 18 that detects the rotation speed of a crankshaft (not shown) of the engine 11, and an accelerator pedal that detects the amount of depression of an accelerator pedal (not shown) operated by the driver. An opening sensor 19, a vehicle speed sensor 20 that detects the running speed of the vehicle, a throttle opening sensor 21 that detects the opening of a throttle valve (not shown), etc. are connected, and detection signals from these various sensors 18 to 21 are connected. is now output.

[0012] In this example, Japanese Patent Laid-Open No. 2-20106
As disclosed in Publication No. 1, the opening/closing operation of the throttle valve is performed by an actuator (not shown) separately from the amount of depression of the accelerator pedal, and the target vehicle speed of the vehicle is determined based on the gear position of the transmission 28 and the accelerator pedal. The throttle valve is opened and closed by the actuator accordingly.

A motor rotation speed sensor 22 that is assembled to the electric motor 16 and detects the rotation speed of its output shaft is connected to the motor control unit 15, and a detection signal from the motor rotation speed sensor 22 is output. It looks like this.

Furthermore, the clutch control unit 13 has an output shaft 23 assembled to the engine clutch 14.
An engine clutch rotation speed sensor 24 that detects the rotation speed of the engine clutch 17 and a motor clutch rotation speed sensor 26 that is assembled to the motor clutch 17 and detects the rotation speed of the output shaft 25 are connected to each other. , 26 are output.

An endless power transmission belt 27 is wound around the output shaft 23 of the engine clutch 13 and the output shaft 25 of the motor clutch 17 via sprockets (not shown), and the input shaft 29 of the transmission 28 is wound around the output shaft 23 of the engine clutch 13 and the output shaft 25 of the motor clutch 17. It is connected to the output shaft 23 side of the engine clutch 13.

In this embodiment, electromagnetic clutches are used as the engine clutch 13 and the motor clutch 17, and the transmission rate of the driving force to the input shaft 29 of the transmission 28 can be adjusted by adjusting the amount of energization. 24,2
The clutch control unit 13 sets this energization amount based on the detection signal from the clutch 6 and the operating state of the vehicle, and outputs it to the engine clutch 13 and the motor clutch 17, respectively.

Furthermore, the transmission 15 of this embodiment employs a type in which a shift position and a select position are 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 a transmission control unit 30.

For this reason, the transmission control unit 30 includes a gear position sensor 3 that is assembled into the transmission 15 and detects the current gear position (hereinafter referred to as gear position).
1, a shift lever position sensor 32 for detecting the position of the shift lever, etc. are connected, and these gear position sensors 3
1, a shift lever position sensor 32, and the like are output.

A heater-equipped catalyst 34 is interposed in the middle of the exhaust pipe 33 that serves as a passage for exhaust gas discharged from the engine 12, and a catalyst for detecting the temperature of the heater-equipped catalyst 34 is installed in the heater-equipped catalyst 34. A temperature sensor 35 is attached. Further, a catalyst control unit 36 is connected to this catalyst temperature sensor 35 and controls turning on/off of electricity to a catalyst heater (not shown) of a catalyst equipped with a heater 34, and a detection signal from the catalyst temperature sensor 35 is transmitted to this catalyst control unit 36.
It is now output to .

The engine control unit 11 and the other control units 13, 15, 30, and 36 are electrically connected to each other via signal cables 37 in order to mutually exchange necessary information. , each control unit 11
, 13, 15, 30, and 36 are transmitted via control cables 38 to the engine 12 to be controlled, the engine clutch 14, the electric motor 16, the motor clutch 17, the transmission 28, and the heater-equipped catalyst 34. is output to.

Therefore, it is difficult to properly purify the exhaust gas from the engine 12 when the heater-equipped catalyst 34 is inactive. 16, and the driving force of this electric motor 16 is adjusted so that the target vehicle speed VO is set based on the detection signal output from the accelerator opening sensor 19 corresponding to the amount of depression of the accelerator pedal by the driver. Control appropriately.

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

However, when the heater-equipped catalyst 34 is activated, the exhaust gas from the engine 12 can be effectively purified. operate,
The throttle valve opening, fuel supply amount, ignition timing, etc. are adjusted so that the target vehicle speed VO is set based on the detection signal output from the accelerator opening sensor 19 in response to the amount of depression of the accelerator pedal by the driver. is set appropriately 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 degree θ corresponding to the amount of depression of the accelerator pedal.

As shown in FIGS. 3 and 4, which represent the flow of processing according to this embodiment, in S1, a process is performed to select either the engine 12 or the electric motor 16 as the drive source for the vehicle. A drive source selection process, which will be described later, is performed, and then it is determined in S2 whether or not a drive source operating flag FD indicating that the drive source selected in step S1 is in operation is set.

If it is determined in step S2 that the drive source operating flag FD is set, that is, that the drive source selected in step S1 is in operation, then step S3
After performing a drive control process to be described later to drive and control this drive source, it is determined in S4 whether or not a drive source switch such as an ignition key is off.

If it is determined in step S4 that the drive source switch is off, that is, that there is a command to stop the drive source, then in S5 the motor is switched off, indicating that the electric motor 16 is being used as a drive source. It is determined whether the selection flag FM has been reset.

If it is determined in this step S5 that the motor selection flag FM has been reset, that is, that the engine 12 is selected as the drive source of the vehicle, the operation of the engine 12 is stopped in S6. After engine stop processing such as stopping fuel supply is performed, the drive source operating flag FD is reset in S7.

If it is determined in step S2 that the drive source operating flag FD is not set, that is, it is determined that the drive source selected in step S1 is stopped,
In S8, it is determined whether the drive source switch is on.

If it is determined in step S8 that the drive source switch is on, that is, that there is a command to start the drive source, it is determined in S9 whether or not the motor selection flag FM has been reset. .

If it is determined in step S9 that the motor selection flag FM has been reset, that is, that the engine 12 has been selected as the drive source of the vehicle, step S10
After engine starting processing such as starting fuel supply is performed in order to start operation of the engine 12, it is determined in S11 whether or not starting of the engine 12 is completed. In this case, in this embodiment, based on the detection signal from the engine speed sensor 18, it is determined that the starting of the engine 12 is completed when the engine speed NE is equal to or higher than a preset value.

If it is determined in this step S11 that the starting of the engine 12 has been completed, the drive source operating flag FD is set in S12, and the process proceeds to the step S4, but the step S11 is If it is determined that the engine 12 has not been started yet, the process directly proceeds to step S4, where it is determined 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 command to start the drive source, the process proceeds to step S4, and it is determined whether or not the drive source switch is off. Make a judgment.

Further, if it is determined in step S9 that the motor selection flag FM has not been reset, that is, the electric motor 16 is selected as the drive source of the vehicle, the electric motor 16 is selected in step S13. After performing a motor starting process such as energizing the electric motor 16 to start operation, it is determined in S14 whether starting of the electric motor 16 has been completed. In this case, in this embodiment, it is determined whether or not the electric motor 16 is started based on detection of a disconnection in the electric motor 16 or the like.

[0036] In this step S14, the electric motor 16
If it is determined that the startup of the
If it is determined in step S14 that the electric motor 16 has not started, the process proceeds to step S4 and the drive source switch is set. Determine whether it is off or not.

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

Further, if it is determined in step S5 that the motor selection flag FM has not been reset, that is, the electric motor 16 is selected as the drive source of the vehicle, the electric motor 16 is selected in step S15. After performing a motor stop process such as cutting off power to the electric motor 16 in order to stop the operation, the process moves to step S7 and the drive source operating flag FD is reset.

As shown in FIG. 5, which shows the flow of the drive source selection process in step S1 described above, first, in C1, the output signal O from the catalyst temperature sensor 35 is preset as the activation temperature of the heater-equipped catalyst 34. In step C1, it is determined whether the output signal O from the catalyst temperature sensor 35 is larger than the first threshold OH, that is, the heater-equipped catalyst 34 is activated. If it is determined that there is a drive source, the power supply to the heater of the heater-equipped catalyst 34 is stopped at C2, and after performing the engine selection process described below in which the engine 12 is selected as the drive source at C3, the S shown in FIG.
Move on to step 2.

[0040] Also, in step C1, the catalyst temperature sensor 3
When it is determined that the output signal O from the catalyst temperature sensor 35 is equal to or lower than the first threshold value OH, the output signal O from the catalyst temperature sensor 35 is determined at C4 to a second threshold value preset as the activation temperature of the heater-equipped catalyst 34. If it is determined in step C4 that the output signal O from the catalyst temperature sensor 35 is smaller than the second threshold OL, that is, the heater-equipped catalyst 34 is not activated. At C5, the heater of the heater-equipped catalyst 34 is energized, and at C6
After performing a motor selection process to be described later in which the electric motor 16 is selected as a drive source, the process moves to step S2 shown in FIG.

On the other hand, if it is determined in step C4 that the output signal O from the catalyst temperature sensor 35 is greater than the second threshold OL, the drive source currently selected is used as is in step C7. , and then proceeds to step S2 shown in FIG.

As described above, in this embodiment, the activation temperature of the heater-equipped catalyst 34 is set between the first threshold value OH and the first threshold value O.
A second threshold value OL is set at a temperature lower than H, in order to avoid causing discomfort to the occupants due to fluctuations in drive torque due to frequent switching between the engine 12 and the electric motor 16 as the drive source. However, it is of course possible to select a driving source based on one threshold value.

As shown in FIG. 6, which shows the flow of the engine selection process in step C3, it is determined in E1 whether or not the motor selection flag FM is set.
If it is determined in step 1 that the motor selection flag FM is set, that is, that the engine 12 is currently stopped, processing for starting the engine 12 such as starting fuel supply is performed in step E2, and then Then, at E3, it is determined whether or not the starting of this engine 12 has been completed.

If it is determined in step E3 that the engine 12 has started, the engine clutch 14 is energized in E4, and the output shaft of the engine 12 is connected to the engine clutch 14 via the engine clutch 14. The input shaft 29 of the transmission 28 is connected, and the motor clutch 17 is de-energized at E5, and the output shaft side of the electric motor 16 and the input shaft of the transmission 28 are separated.

After that, at E6, motor operation stop control is performed to stop the operation of the electric motor 16, such as cutting off the power supply to the electric motor 16, and then the motor selection flag FM is reset, and then the process shown in FIG. 3 is performed. The process moves to step S2.

It should be noted that if the motor selection flag FM is not set in step E1, that is, engine 12 is currently selected.
If it is determined that the engine 12 is in operation, or if it is determined at E3 that starting of the engine 12 has not been completed, the process directly proceeds to step S2 shown in FIG.

On the other hand, as shown in FIG. 7, which shows the flow of the motor selection process in step C6 mentioned above, it is determined in M1 whether the motor selection flag FM is reset, and the process proceeds to step M1. If it is determined that the motor selection flag FM has been reset, that is, that the engine 12 is running, M2 performs motor startup processing such as starting energization of the electric motor 16, and then M3 It is determined whether starting of this electric motor 16 is completed.

If it is determined that the starting of the electric motor 16 is completed in step M3, the motor clutch 17 is energized in M4, and the motor clutch 17 is energized.
7, the output shaft of the electric motor 16 and the input shaft 29 of the transmission 28 are connected by a power transmission belt 27 via the motor clutch 17, and the engine clutch 14 is connected to the engine clutch 14 via M5.
The output shaft side of the engine 12 and the transmission 2 are de-energized.
8 and the input shaft 29.

Thereafter, at M6, an engine stop process is performed to stop the operation of the engine 12, and then the motor selection flag FM is set, and then the process moves to step S2 shown in FIG.

It should be noted that if it is determined that the motor selection flag FM has not been reset in step M1, that is, that the engine 12 is in operation, or if it is determined that starting of the electric motor 16 has not been completed in M3. If so, the process directly proceeds to step S2 shown in FIG.

As shown in FIG. 8, which shows the flow of the drive control process in step S3, first, in D1, the accelerator is activated 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 θA is detected, and at D2, the target vehicle speed VO corresponding to this accelerator opening degree θA is read from the map as shown in FIG. 2 described above.

In this embodiment, as a method for calculating the accelerator opening degree θA, the previously calculated accelerator opening degree θA(n-1
) and a filter constant K, and are set as shown in the following formula. θA=K·θA(n-1)+(1-K)·P However, P is the output from the 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 based on this gear position and the target vehicle speed VO, the engine 12 or electric motor serving as the drive source is detected. In this embodiment, the target rotation speed NO.16 is calculated at D4 using the following formula. NO=VO・1000・i/60・2・π・R However, i
is the total reduction ratio of the drive system, π is pi, and R is the radius of the wheel (not shown).

Then, at D5, the motor selection flag FM
is reset, and if it is determined in step D5 that the motor selection flag FM is reset, that is, the engine 12 is selected as the drive source, the engine is selected in step D6. The engine rotation speed NE is detected based on the output signal from the rotation speed sensor 18, and it is determined in D7 whether or not the engine rotation speed NE is larger than the target rotation speed NO.

If it is determined in step D7 that the engine speed NE is larger than the target speed NO, that is, the engine speed NE is too high, the operation of the actuator is controlled to close the throttle valve. engine speed NE
After approaching the target rotation speed NO, the above-mentioned S4 shown in FIG.
Move to the next step.

If it is determined in step D5 that the motor selection flag FM has not been reset, that is, the electric motor 16 is selected as the drive source, step D9 is determined.
At D10, the rotation speed NM of the electric motor 16 is detected based on the output signal from the motor rotation speed sensor 22, and at D10 it is determined whether or not this motor rotation speed NM is larger than the target rotation speed NO.

At this step D10, the motor rotation speed N
M is larger than the target rotation speed NO, that is, the motor rotation speed N
If it is determined that M is too high, the motor drive current is decreased by a predetermined amount in D11 to bring the motor rotation speed NM closer to the target rotation speed NO, and then the S shown in FIG.
Move on to step 4. Further, if it is determined in step D10 that the motor rotation speed NM is smaller than the target rotation speed NO, that is, the motor rotation speed NM is too low, D
At step 12, the motor drive current is increased by a predetermined amount to bring the motor rotation speed NM closer to the target rotation speed NO, and then the process moves to step S4 shown in FIG.

On the other hand, if it is determined in step D7 that the engine speed NE is smaller than the target engine speed NO, that is, the engine speed NE is too low, the actuator is operated to open the throttle valve. After controlling the engine speed NE to bring the engine speed NE closer to the target speed NO, the S shown in FIG.
Move on to step 4.

[0059] In this embodiment, the engine 12 which is the drive source
Although the electric motor 16 and the electric motor 16 are arranged in parallel, it is of course possible to arrange the 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 together with the motor even while the engine is running, so it can be used as a flywheel, but generally the rotor has coils, permanent magnets, etc. It is desirable to adopt a type with a small inertial mass that includes only an unincorporated iron core. Also, engine 1
2 and the electric motor 16 are connected in series, it becomes unnecessary to use the motor clutch 17, the power transmission belt 27, etc., and the processing of step E5 shown in FIG. 6 and the M4 shown in FIG. It is also possible to omit the processing of the step.

Further, in this embodiment, the target vehicle speed of the vehicle is set based on the accelerator opening, but according to Japanese Patent Application Laid-Open No. 2-2
As disclosed in Japanese Patent No. 02058, the target drive torque of the drive source may be set based on the accelerator opening and the rate of change in the accelerator opening.

[0061]

[Effects of the Invention] According to the method for controlling the operation of a vehicle equipped with a heater-equipped catalyst of the present invention, when the catalyst is inactive, the internal combustion engine is not operated and the vehicle is driven by the electric motor. Since no exhaust gas is generated, the 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 operation of the internal combustion engine are rendered harmless by the catalyst, and the harmful components are reduced as a whole. It is possible to significantly reduce emissions.

On the other hand, since the driving conditions with the electric motor are limited to the period when the catalyst is inactive, the capacity of the electric motor and the capacity of the storage battery that supplies power to it are reduced compared to ordinary electric vehicles. is possible.

Furthermore, even in a cold state, the electric motor can immediately start the vehicle, which is very advantageous in terms of practicality in emergencies.

[Brief explanation of the drawing]

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

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

FIG. 3 is a flowchart together with FIG. 4 showing the process flow of the operation control method according to the present embodiment.

FIG. 4 is a flowchart showing the process flow of the operation control method according to the present embodiment together with FIG. 3;

FIG. 5 is a flowchart showing the flow of drive source selection processing in FIG. 3;

FIG. 6 is a flowchart showing the flow of engine selection processing in FIG. 5;

FIG. 7 is a flowchart showing the flow of motor selection processing in FIG. 5;

FIG. 8 is a flowchart showing the flow of drive control processing 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 rotation speed sensor, and 19 is an accelerator opening. 20 is a vehicle speed sensor, 21 is a throttle opening sensor,
22 is a motor rotation speed sensor, 24 is an engine clutch rotation speed sensor, 26 is a motor clutch rotation speed sensor, 27
1 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, 37 is a signal cable, 3
8 is a control cable.

Claims (1)

[Claims] Claim 1: A vehicle comprising a catalyst provided in the middle of an exhaust passage connected to an internal combustion engine for purifying exhaust gas discharged from the internal combustion engine, and a heater for raising the catalyst to its activation temperature. The vehicle is driven by an electric motor separate from the internal combustion engine, the internal combustion engine is not started until the catalyst is activated, the vehicle is driven by the electric motor, and the catalyst is activated. A method for controlling the operation of a vehicle equipped with a heater-equipped catalyst, characterized in that after activation, the electric motor is stopped, the internal combustion engine is started, and the vehicle is driven by the internal combustion engine.