JP2001329895A - Control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate with high accuracy the evaporated fuel purged by compensating the shortage of engine power by a motor from a change in feedback value. SOLUTION: When the engine power requirement torque TR for a vehicle becomes larger than a specified threshold value Tref, uniform combustion is conducted by O2 feedback control only for a specified time TI in stead of switching the engine running in a stratified combustion range to that in a rich combustion range under normal conditions for estimating the value of vaporized fuel quantity for the time TI by calculation and also the quantity of the vaporized fuel purged highly accurately by compensating the shortage of output torque TE of the engine by motor torque TM.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a control device for a vehicle.

[0002]

2. Description of the Related Art In a hybrid vehicle, an engine load at the time of purging evaporative fuel is set to be smaller than an engine load at the time of charging a battery.
Japanese Patent Application Laid-Open No. Hei 11-44237), and in a lean burn engine, when it is determined that fuel vapor has accumulated during lean operation, the purge is performed by operating at a stoichiometric air-fuel ratio every predetermined period. Gazette) has been proposed.

[0003]

However, when the engine is accelerated or restarted, the air-fuel ratio fluctuates, so that the fuel vapor cannot be accurately estimated.

[0004] Therefore, a method of estimating the purged fuel vapor amount from the change in the feedback value due to the purged vapor fuel amount during the O ₂ feedback control of the air-fuel ratio has been adopted.

However, hybrid vehicles and the like
In order to perform a stratified combustion operation with a lean air-fuel ratio to improve fuel efficiency, when performing O ₂ feedback control using a λO ₂ sensor whose detection signal is inverted between rich and lean based on the stoichiometric air-fuel ratio, The output of the λO ₂ sensor hardly changes in the combustion region. For this reason, it becomes impossible to estimate the purged fuel vapor amount from the change in the feedback value.

The present invention has been made in view of the above circumstances, and has as its object to estimate the amount of purged fuel vapor from a change in the feedback value, and to assist the motor in assisting the engine output shortage to remove the purged fuel vapor. An object of the present invention is to provide a vehicle control device that can estimate fuel with high accuracy.

[0007]

Means for Solving the Problems To solve the above problems and achieve the object, a vehicle control device of the present invention has the following arrangement. That is, an engine and / or motor for driving wheels, motor control means for controlling the output of the motor, a steam fuel path for connecting the fuel tank to an intake passage of the engine via a barge valve, Purge control means for controlling the degree of opening of the purge valve so as to supply the fuel vapor inside the intake passage to the intake passage, and control so that the air-fuel ratio of the air-fuel mixture sucked into the combustion chamber of the engine converges to a predetermined air-fuel ratio. The air-fuel ratio control means and the air-fuel ratio control means open the purge valve during control by the air-fuel ratio control means. A control unit for controlling the air-fuel ratio to be the predetermined air-fuel ratio when the output demand of the vehicle is large. In both cases, the estimating means estimates the amount of fuel vapor, and the motor control means, when the output demand of the vehicle is large, the motor output related value is calculated based on the vehicle output demand related value from the vehicle output demand related value. The motor output is controlled so as to substantially coincide with a value obtained by subtracting a related value of the engine output controlled by the above.

Preferably, the air-fuel ratio control means controls the air-fuel ratio so as to alternately change rich or lean based on the stoichiometric air-fuel ratio when the output demand of the vehicle is large.

Preferably, the air-fuel ratio control means controls the air-fuel ratio leaner than the predetermined air-fuel ratio when the output demand of the vehicle is small.

[0010] Preferably, the purge control means controls the purge valve based on the amount of fuel vapor estimated by the estimation means.

Preferably, the air-fuel ratio control means controls the air-fuel ratio leaner than the predetermined air-fuel ratio when the output demand of the vehicle is large, and based on the fuel vapor amount estimated by the estimation means. And controlling the purge valve when the air-fuel ratio is set to lean.

[0012]

As described above, according to the first aspect of the present invention, the purge valve is opened during the air-fuel ratio control, and the related value of the actual air-fuel ratio and the related value of the predetermined air-fuel ratio while the purge valve is opened. When estimating the amount of evaporative fuel based on the difference from the above, when the output demand of the vehicle is large, control is performed so that the air-fuel ratio becomes a predetermined air-fuel ratio, and the amount of evaporative fuel is estimated. By controlling the motor output such that the value substantially matches the value obtained by subtracting the related value of the engine output controlled by the air-fuel ratio from the related value of the output request of the vehicle, the amount of the evaporated fuel purged from the change in the feedback value can be calculated. At the time of estimation, it is possible to estimate the purged fuel vapor with high accuracy by assisting the motor with insufficient output of the engine.

According to the second aspect of the present invention, when the output demand of the vehicle is large, the air-fuel ratio is controlled so as to alternately change rich or lean based on the stoichiometric air-fuel ratio, so that it is inexpensive and close to the stoichiometric air-fuel ratio. Since a high-precision sensor can be used, the controllability of the air-fuel ratio is improved, so that the purged fuel vapor can be estimated with high accuracy. For example, if a three-way catalyst is used, the purification efficiency of the exhaust gas is also improved.

According to the third aspect of the invention, when the output demand of the vehicle is small, the stratified fuel region is set by controlling the air-fuel ratio leaner than the predetermined air-fuel ratio, that is, the operation period at the stoichiometric air-fuel ratio, that is, Even if the engine has a short estimated period of the purged fuel vapor, the estimated period can be secured.

According to the fourth aspect of the present invention, the purge valve is controlled based on the estimated amount of the evaporated fuel, so that the adsorbed evaporated fuel can be released to the atmosphere.

According to the present invention, when the output demand of the vehicle is large, the air-fuel ratio is controlled to be leaner than the predetermined air-fuel ratio, and the air-fuel ratio is set to lean based on the estimated amount of fuel vapor. By controlling the purge valve when the engine is operated, the stratified fuel region is set and the engine is operated at the stoichiometric air-fuel ratio, that is, even if the engine has a short estimated period of the purged fuel vapor, the engine can release the adsorbed vapor fuel to the atmosphere. Can be suppressed.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. [Mechanical Configuration of Hybrid Vehicle] FIG. 1 is a block diagram showing the mechanical configuration of the hybrid vehicle of the present embodiment.

As shown in FIG. 1, the hybrid vehicle according to the present embodiment includes an engine 1 for driving left and right wheels (front wheels or rear wheels) 7 and 8 via an automatic transmission 3, and a clutch 4.
And a motor 2 which is provided so as to be able to be fastened in the middle of an output transmission path from the engine 1 via the motor 1 and which applies a driving force in an auxiliary manner.

The motor 2 is driven by the electric power of the battery 5 via the inverter 6, and at the time of deceleration and braking, the wheels 7, 8 act as a generator to drive the motor 2 to generate regenerative electric power. I do.

The wheels 7 and 8 are mainly driven by the engine 1, and a driving force is applied from the motor 2 by engaging the clutch 4. The clutch 4 includes a friction element driven by an actuator and a planetary gear train.

The engine 1 is a direct-injection gasoline engine or a fuel-efficient type that delays the closing timing of an intake valve as a main power source, and the motor 2 is an auxiliary power source such as an IPM synchronous motor having a maximum output of 20 kW. The battery 3 is equipped with, for example, a nickel hydrogen battery having a maximum output of 20 kW.

The main controller 10 includes a CPU, an RO
M, RAM, an interface circuit, an inverter circuit, and the like, and controls the opening degree, ignition timing, fuel injection amount, and the like of the throttle valve, EGR valve, and swirl valve of the engine 1 and the output torque MT and the rotation speed NM of the motor 2. And the like are controlled so as to absorb the torque fluctuation of the engine 1 and the shift shock of the automatic transmission 7. Also, the main controller 10
Controls the battery 3 to charge the electric power generated by the motor 2 during the operation of the engine 1. [Detailed Configuration of Engine] FIG. 2 is a schematic diagram of the direct injection gasoline engine of the present embodiment.

As shown in FIG. 2, the engine 1 has a cylinder 12, a piston 14 is mounted on the cylinder 12, and a combustion chamber 16 is formed above the piston 14. Combustion chamber 16
, An intake port and an exhaust port, each of which is branched into two, are formed. The intake port is opened and closed by an intake valve 17, and the exhaust port is opened and closed by an exhaust valve 18.

An ignition plug 20 is disposed above the combustion chamber 16 such that a front end spark portion faces the combustion chamber 16. Further, a fuel injection valve 22 is provided on a side of the combustion chamber 16, and fuel is directly injected into the combustion chamber 16 from the fuel injection valve 22. In the fuel injection mode, fuel is injected into the upper surface of the piston to rebound the spark plug.

The fuel injection valve 22 has a built-in needle valve and solenoid (not shown), and a pulse signal is applied to the solenoid to inject fuel in an amount corresponding to the pulse width.

An intake port 24 is connected to the intake port, and an air cleaner 25, an air flow sensor 26, a throttle valve 28, and a surge tank 30 are provided in this order from the upstream side.

The throttle valve 28 is operated by an electric actuator such as a step motor so that the amount of intake air can be controlled.

The intake passage on the downstream side of the surge tank 30 branches into two corresponding to the intake port, and a swirl valve 32 is provided in one of the branch passages.

The swirl valve 32 opens and closes the one of the branch passages, and is closed at least in the stratified combustion region of the engine to a fully closed state or a state close to the fully closed state.
A swirl is generated in 6.

An exhaust passage 34 is connected to the exhaust port, and a catalyst 35 having a three-way function and a lean NOx catalyst 36 for adsorbing NOx in the stratified combustion region are arranged in the exhaust passage 34. The exhaust passage 16 is provided with a λO ₂ sensor 15 for detecting the air-fuel ratio in the exhaust gas.

The catalyst 35 having a three-way function includes HC, CO,
Purify NOx. When performing the stratified combustion with the air-fuel ratio in the lean region of λ> 1 after the warm-up, the lean NOx catalyst 36 has an air-fuel ratio λ> 1 leaner than the stoichiometric air-fuel ratio λ = 1 (the oxygen concentration in the exhaust gas is (2% or more) is continued for several minutes to adsorb NOx. Also, lean NO
The x catalyst 36 exhibits a three-way function near the stoichiometric air-fuel ratio λ = 1, and provides an air-fuel ratio near λ = 1 or richer than λ = 1 (when the oxygen concentration is 1% or less, HC and CO are supplied. NOx adsorbed when (state) continues for several seconds
To react with HC and CO.

Further, between the exhaust passage 34 and the intake passage 24, an EGR passage 4 for returning a negative portion of the exhaust gas to the intake system.
The EGR passage 43 can be opened and closed by an EGR valve 44.

The throttle valve 2 is provided in the intake passage 24.
A bypass passage 50 for bypassing the bypass passage 8 is provided, and a bypass valve 52 is provided in the bypass passage 50 to open and close the bypass passage 50, so that the amount of intake air can be controlled.

Further, in addition to the λO ₂ sensor (or linear O ₂ sensor) 15 and the airflow sensor 26, the engine 1 has an engine speed sensor 37, a throttle valve opening sensor 38, a brake pedal switch 39, a parking brake. A switch 40, a shift range sensor 41, and an accelerator pedal switch 42 are provided, and detection signals of the sensors and switches are output to the main controller 10.

The engine 1 is provided with a canister 61 filled with an adsorbent (for example, activated carbon) for collecting (adsorbing) the evaporated fuel (gasoline vapor) in the fuel tank 60.

The canister 61 has a fuel tank 6 at the tip.
The space 6 of the fuel tank 60 communicates with the space 60a
A relief passage 62 for relieving air (purge gas) containing evaporative fuel staying in Oa to the canister 61, an atmosphere opening passage 63 whose tip is open to the atmosphere, and a purge passage 64 are connected. Note that the end of the atmosphere opening passage 63 may be connected to the upstream side of the throttle valve 28. Also, instead of filling the canister 61 with an adsorbent,
A material for collecting the evaporated fuel may be filled by using a phenomenon other than adsorption (for example, absorption, reaction, or the like) (however, a material that can be purged with air).

The purge passage 64 is provided with a duty solenoid type purge control valve 65 capable of opening and closing the purge passage 64 arbitrarily. The duty limit of the purge control valve 65 is controlled by the main controller 10. It has become. The purge control valve 65 is controlled to open and close in accordance with the drive duty ratio applied from the main controller 10. For example, when the drive duty ratio is 0, it is fully closed, when the drive duty ratio is 100%, it is fully opened. The greater the ratio, the greater the degree of valve opening.

When the purge control valve 65 is fully closed (drive duty ratio 0), the air in the fuel tank 60 is relieved into the canister 61 through the relief passage 62 and then into the atmosphere through the atmosphere opening passage 63. Although discharged, the evaporated fuel contained in the air is collected by the adsorbent when passing through the adsorbent layer in the canister 61 and is not discharged into the atmosphere.

On the other hand, when the purge control valve 65 is open, the air in the atmosphere is first sucked into the canister 61 through the atmosphere opening passage 63 and passes through the adsorbent layer due to the negative pressure in the intake passage 24. Rear purge passage 6
From 4, the combustion chamber 16 is purged via the surge tank 30.

The flow rate of the air to be purged (hereinafter referred to as the purge air amount) changes in accordance with the degree of opening of the purge control valve 65 (ie, the drive duty ratio). At that time, a part of the evaporated fuel collected by the adsorbent in the canister 61 is separated from the adsorbent, and is purged into the combustion chamber 16 through the intake passage 24 together with the purge air.
Hereinafter, the flow rate of the evaporated fuel purged from the intake passage 24 into the combustion chamber 16 is referred to as “evaporated fuel purge amount”.

Next, referring to the basic operation mode of FIG.
Control of the engine 1, the motor 2, and the automatic transmission 3 in the main state will be described. [During steady running] The output required torque TR of the vehicle is equal to a predetermined threshold T.
If the state is larger than ref (TR ≧ Tref), the clutch 4
And the engine 1 and the motor 2 are driven by the engine torque TE and the motor torque TM according to the output required torque TR.
Is output. The automatic transmission 3 is set to the forward traveling range. The engine torque TE and the motor torque TM are set to larger values as the required output torque TR increases.

Further, the output required torque TR is set at a predetermined threshold value Tre.
If it is smaller than f (T <Tref), the clutch 4 is engaged, but the motor 2 does not output the driving torque TM, and the engine 1 outputs the driving torque TE according to the output request torque TR. The automatic transmission 3 is set to the forward traveling range. [At idle stop] When the brake pedal switch 39 or the parking brake switch 40 is on and the shift range sensor 41 indicates the forward running range, it is determined that the engine is at idle stop, and the clutch 4 is engaged but the engine 1 And the motor 2 is stopped.
The automatic transmission 3 is set to the forward traveling range. Further, when the brake pedal switch 39 or the parking brake switch 40 is turned off in the forward traveling range, the idling operation of the engine 1 is restarted. [Stopping] When the brake pedal switch 39 or the parking brake switch 40 is off and the shift range sensor 41 indicates the neutral range or the parking range, it is determined that the vehicle is at a stop, the clutch 4 is released, and the engine 1 and the motor 2 are turned off. Stopped. [When the charged amount of the battery 5 is small or abnormal] When the charged amount of the battery 5 is small or when the battery 5 is abnormal (TR> 0) while the vehicle is running, the clutch 4 is connected to the engine 1 and the motor 2. On the other hand, the wheels are connected to the engine 1 and the motor 2 so as to be released, the engine 1 outputs a driving torque TE according to the output required torque TR, and the motor 2 is driven by the engine 1 as a generator. Battery 3
Charge. [Electrical Configuration of Hybrid Vehicle] FIG. 4 is a block diagram showing the electrical configuration of the hybrid vehicle of the present embodiment.

As shown in FIG. 4, the main controller 1
2, the vehicle speed sensor 55 for detecting the vehicle speed V, the remaining charge sensor 56 for detecting the remaining charge SC of the battery 5, and the temperature of the hydraulic oil of the automatic transmission 3 are set to 0 in addition to the sensors and switches shown in FIG. A detection signal is input from an oil temperature sensor or the like, and data on an operating state of the vehicle, a vehicle speed V, an engine speed NE, a voltage, a gasoline remaining amount, a storage remaining amount SC of the battery 5, a shift from the detection signals of the various sensors are input. The range, the power supply system, and the like are displayed on a display 57 such as an LCD.

[0044] Further, the main controller 10 integrally controls the engine 1 and the motor 2, .lamda.o ₂ sensor 15
(Or a linear O ₂ sensor), the O ₂ concentration in the exhaust gas detected by the throttle valve opening sensor 38
The opening degree of the throttle valve detected by the engine, the intake air amount detected by the air flow sensor 26, the engine speed detected by the engine speed sensor 37, the idle signal output from the idle switch, and the like are used as control information. Various controls and estimation of the amount of evaporated fuel collected by the canister 61 are performed.

The main controller 10 controls the current engine 1 based on the detection signals of the various sensors and switches.
It is determined which of the operation regions shown in FIG. Each operating region is defined based on the engine speed NE and the engine torque TE (engine load).

In FIG. 9, a region A is a low-medium-speed low-load operation region in which the fuel injection amount is small, and in the stratified combustion operation, that is, as shown in FIG. 10, the latter half of the compression stroke (for example, before the compression top dead center). (BTDC) 90 ° to 30 °), the entire combustion chamber 16 is relatively and locally compared with other regions only in the vicinity of the spark plug 20 while keeping the fuel in a lean state. A stratified combustion operation is performed in which the fuel is made rich and ignited.

The region B is a region where the rotation speed and the load are higher than the region A, and the stoichiometric air-fuel ratio (λ = 1, A / A
F = 14.7) and the region where uniform combustion is performed. That is, in the region B, as shown in FIG. 11, the fuel is injected in the first half of the injection stroke from the intake stroke to the first half of the compression stroke, and the fuel is injected in the second half of the compression stroke (for example, 90 ° to 30 ° before the compression top dead center (BTDC)). The fuel is divided into at least two of the latter injections for injecting the fuel, so that the ignition plug 20
Is set based on the engine speed NE and the intake air amount Q so that the fuel becomes relatively and locally richer only in the vicinity of the other regions than in other regions.

The region C is a region where the rotation speed and the load are higher than the region B, and the air-fuel ratio is rich (λ <1, A / F = 14.7).
~ 13.0) combustion operation, and as shown in FIG.
This is a region in which fuel is injected at a time from the intake stroke to the first half of the compression stroke.

The region D is a region where the rotation speed and the load are higher than the region C, and the air-fuel ratio is rich (λ <1, A / F = 12.
As shown in FIG. 12, this is a region where fuel is injected in a batch from the intake stroke to the first half of the compression stroke.

The general control of the engine 1 is well known, and such general control is not the subject of the present invention. Therefore, the description thereof is omitted, and the following description relates to the subject of the present invention. The air-fuel ratio control (fuel injection amount control), the estimation of the amount of evaporated fuel, and the control of the purge control valve will be described.

The prerequisite technique of the present invention will be described with reference to the timing chart of FIG. 22. During the O ₂ feedback control of the air-fuel ratio in the uniform combustion region, the purge control valve is fully opened to purge the evaporated fuel. Then, since the air-fuel ratio fluctuates due to the purged fuel vapor, the feedback value changes to converge to the stoichiometric air-fuel ratio. The purged fuel vapor amount EV is estimated from the change in the feedback value (average value).

Based on the above technology, the gist of the present invention is as follows.
An example will be described with reference to the timing chart of FIG. 21. When the output required torque TR of the vehicle is larger than a predetermined threshold Tref, the operation of the engine 1 is normally switched from a stratified combustion region to a rich combustion region. Evaporated fuel is purged by performing uniform combustion by O ₂ feedback control for a predetermined period T1 and calculating the estimated value EV of the amount of evaporated fuel during the period T1 and supplementing the insufficient output of the engine torque TE with the motor torque TM. The fuel can be estimated with high accuracy. In addition, by correcting the opening degree PG of the purge control valve 65 based on the estimated value EV of the evaporative fuel amount (PG = PBASE + PC), the engine operation considering the evaporative fuel amount after the period T1 is realized. I have.

Hereinafter, embodiments of the gist of the present invention will be described with reference to flowcharts. [Overall Control] FIG. 5 is a flowchart showing overall control of the hybrid vehicle of the present embodiment.

As shown in FIG. 5, the present control program is executed at predetermined time intervals. In step S1, data is input from the sensors and switches shown in FIGS.

In step S3, the required output torque TR of the vehicle is set from the relationship between the vehicle speed V (or the engine speed NE) and the accelerator opening α in FIG.

In step S5, it is determined whether the required output torque TR is equal to or greater than a predetermined threshold value Tref. If the output required torque TR is equal to or larger than the predetermined threshold Tref in step S5 (step S
If the answer is YES in step S7, the process proceeds to step S7.
Go to 25. In step S5, it may be determined whether the engine should be restarted from an idle stop due to a sudden acceleration request or a sudden acceleration request.

In step S7, it is determined whether the remaining charge SC of the battery 5 is equal to or greater than a predetermined amount SC0 and the battery is normal. In step S7, if the remaining charge SC of the battery 5 is equal to or more than the predetermined amount SC0 and the battery is normal (step S7
Then, the process proceeds to step S9, and if the remaining charge SC of the battery 5 is less than the predetermined amount SC0 or if the battery is abnormal (NO in step S7), the process proceeds to step S25 described later.

In step S9, if the engine 1 is not operated in the rich region where the air-fuel ratio is λ <1, the engine 1 outputs the required output torque T
Since the required output torque TR is so large that R cannot be output, the flag F is set. Flag F indicates engine 1
Is set based on the high load map shown in FIG.

In step S11, the counter T is incremented. In step S13, the counter T is set to a predetermined time T1.
Has elapsed (YES in step S13), the process proceeds to step S27 described below. If the predetermined period T1 has not elapsed (NO in step S13), the process proceeds to step S15.

In step S15, the output torque TEλ1 of the engine 1 is calculated from the high load map shown in FIG. The output torque TEλ1, when the detection signal relative to the stoichiometric air-fuel ratio (lambda = 1) performs the O ₂ feedback control using the .lamda.o ₂ sensor 15 which inverts to the rich or lean, by inhalation followability of the feedback control The value is set to a value that can maintain the stoichiometric air-fuel ratio (λ = 1) even when the air amount increases.

In step S17, a motor torque TM is calculated. The motor torque TM is set to substantially match a value obtained by subtracting the output torque TEλ1 of the engine 1 from the required output torque TR of the vehicle.

In step S19, the engine torque TE
Is set to the output torque TEλ1 calculated in step S15, the engine 1 is operated in accordance with the engine torque TE in step S21, and the motor 2 is driven in accordance with the motor torque TM in step S23.

In step S25, even if the engine 1 is operated in the lean region where the air-fuel ratio is λ ≧ 1, the engine 1
If the output request torque TR that can output R is not so large, or the remaining charge SC of the battery 5 is small or the battery is abnormal, and the timer T is counting (YES in step S25), the process proceeds to step S11. ,
If the count of the timer T is completed (step S25)
NO), and the process proceeds to step S27.

In step S27, the flag F, the engine torque TE, and the motor torque TM set during the timer count are reset, and in step S29, based on the vehicle output required torque TR in accordance with the basic operation mode of FIG. Then, the engine torque TE and the motor torque TM are set, and the process proceeds to step S21.

In step S29, the engine torque TE is set from a map showing the relationship between the engine speed NE and the vehicle output required torque TR in FIG.
The shift speed of the automatic transmission 3 is set from a map showing the relationship between the vehicle speed V and the accelerator opening α. [Engine Control] FIGS. 6 and 7 are flowcharts showing details of engine control.

As shown in FIG. 6, this control program is executed at every predetermined crank angle, and in step S31, data is inputted from the sensors and switches shown in FIGS.

In the step S33, it is determined whether or not the flag F is set. If the flag F is set in step S33 (YES in step S33), the process proceeds to step S35. If the flag F is not set (NO in step S33), the process proceeds to step S63 in FIG.

In step S35, the throttle valve opening T is obtained from the map showing the relationship with the engine torque TE in FIG.
Set V.

In step S37, the throttle valve 2 is set in accordance with the throttle valve opening TV set in step S35.
8 is driven.

In step S39, a basic fuel injection amount FnBASE is set from a map showing the relationship between the engine speed NE and the intake air amount Q in FIG.

[0071] At step S41, λO ₂ O ₂ concentration λ is a predetermined value in the exhaust gas detected by the sensor 15 .lambda.1
Determine if greater than. If the O ₂ concentration λ is larger than the predetermined value λ1 in step S41 (YE
S), since it is richer than the stoichiometric air-fuel ratio (λ = 1, A / F = 14.7), the correction value β is subtracted from the feedback value FnF / B of the fuel injection amount in step S43, and step S45 is performed.
Then, the correction value γ is added to the estimated value EV of the evaporated fuel amount, and the process proceeds to step S51. Here, β> γ.

If the O ₂ concentration λ is equal to or smaller than the predetermined value λ1 in step S41 (NO in step S41), the fuel is leaner than the stoichiometric air-fuel ratio (λ = 1, A / F = 14.7), and the fuel Injection amount feedback value FnF / B
And the correction value γ is subtracted from the estimated value EV of the evaporated fuel amount in step S49, and the process proceeds to step S51.

In steps S41 to S49, λ
Although the O ₂ feedback control of the air-fuel ratio is performed using the O ₂ sensor 15, the O ₂ feedback control is performed using the linear O ₂ sensor at the air-fuel ratio (for example, A / F 18 to ₂ ) detectable by the sensor. May be performed to estimate the amount of evaporated fuel.

Instead of the O ₂ feedback control of the air-fuel ratio, the amount of fuel vapor may be estimated while the fuel injection amount is controlled to a predetermined air-fuel ratio by feedforward control.

In step S51, in order to perform stable feedback control, the feedback value FnF / B set in steps S43 to S49 is in the range from the lower limit value Fn1 (negative value) to the upper limit value Fn2 (positive value). If it is within the range from the lower limit Fn1 (negative value) to the upper limit Fn2 (positive value) (YES in step S51), the feedback value FnF / B is used as it is in step S5.
3 and if it is not in the range from the lower limit Fn1 (negative value) to the upper limit Fn2 (positive value) (N in step S51).
O), the feedback value FnF / B is set to the lower limit Fn1 or the upper limit Fn2, and the process proceeds to step S53.

In step S53, the basic fuel injection amount Fn
The feedback value FnF / B is added to BASE to calculate the total fuel injection amount Fn. Here, the larger the average value of the estimated value EV of the evaporated fuel amount is, the larger the basic fuel injection amount Fn is.
Correction may be made to reduce BASE.

In step S55, the total fuel injection amount Fn is divided into two equal parts to divide the fuel injection amount FnL and the fuel injection amount FnL.
nT, and a first-stage injection timing InL corresponding to the first-stage injection amount FnL and a second-stage injection timing InT corresponding to the second-stage injection amount FnT are set.

In step S57, the ignition timing θig is set from the map shown in FIG.

In step S59, fuel is injected with the first-stage injection amount FnL and the first-stage injection timing InL and the second-stage injection amount FnT and the second-stage injection timing InT set in step S55. In step S61, the ignition timing set in step S57 is set. The ignition is executed at θig.

On the other hand, if the flag F is not set in step S33 (NO in step S33), the output required torque TR of the vehicle is low, so that step S33 in FIG.
At 63, the feedback value FnF / B and the estimated value EV of the fuel vapor amount are reset.

In step S64, the throttle valve opening degree T is obtained from the map showing the relationship with the engine torque TE in FIG.
Set V.

In step S65, the throttle valve 2 is set in accordance with the throttle valve opening TV set in step S64.
8 is driven.

In step S69, the basic fuel injection amount FnBASE is set from a map showing the relationship between the engine speed NE and the intake air amount Q in FIG.

In step S71, the basic fuel injection amount Fn
BASE is set to the total fuel injection amount Fn. Here, the larger the average value of the estimated value EV of the evaporated fuel amount is,
The correction may be made so that the basic fuel injection amount FnBASE is reduced.

At step S71, the total fuel injection amount Fn is divided into two equal parts to divide the fuel injection amount into the first injection amount FnL and the second injection amount Fn.
nT, and a first-stage injection timing InL corresponding to the first-stage injection amount FnL and a second-stage injection timing InT corresponding to the second-stage injection amount FnT are set.

In step S73, the ignition timing θig is set from the map of FIG. Thereafter, the process proceeds to steps S59 and S61 in FIG. [Control of Purge Control Valve] FIG. 8 is a flowchart showing details of control of the purge control valve.

As shown in FIG. 8, in step S81,
Data is input from the sensors and switches shown in FIGS. Note that the purge control valve 65 is fully closed when the engine is stopped.

In step S83, the basic purge control valve opening PBASE is set from the map showing the relationship with the air-fuel ratio in FIG.

In step S85, it is determined whether the flag F has been set. If the flag F is set in step S85 (YES in step S85), the process proceeds to step S87, and if not (NO in step S85), the process proceeds to step S97 described later.

In step S87, step S4 in FIG.
5 or the estimated value EV of the fuel vapor amount estimated in S49 is read.

In step S89, the previous value EVn-1 and the current value step E
An average with Vn is calculated.

In step S91, the estimated value EV of FIG.
A correction value PC of the purge control valve opening PG is set from a map indicating the relationship with the smoothing value. This correction value PC is shown in FIG.
As shown by 0, control stability is achieved by setting the value not to exceed the upper limit value PC1.

In step S93, the correction value PC is added to the basic purge control valve opening PBASE to obtain the purge control valve opening PBASE.
Calculate G. The purge control valve opening PG may also be set so as not to exceed the upper limit value to achieve control stability.

In step S95, the purge control valve opening P
The purge control valve 65 is driven based on G.

In step S97, the latest correction value PC is read. In step S99, the correction is performed such that the leaner the air-fuel ratio, the smaller the correction value PC. Thereafter, the process proceeds to step S93. Step S99 → S93
Since the basic purge control valve opening PBASE is always maintained, the purge control valve 65 is opened even during stratified combustion. Therefore, accumulation of the evaporated fuel in the canister 61 can be prevented.

As described above, according to the present embodiment, when estimating the purged evaporated fuel amount EV from the change in the O ₂ feedback value FnF / B of the air-fuel ratio, when the output demand of the vehicle is large, (F = 1), using .lamda.o ₂ sensor 15 lambda =
By performing the O ₂ feedback control of 1 and setting the shortage of the engine torque TE to the motor torque TM, it is possible to estimate the evaporated fuel purged by assisting the motor with the insufficient output of the engine by the motor.

Further, since the O ₂ feedback control of λ = 1 is performed using the λO ₂ sensor 15, an inexpensive and high-precision sensor near λ = 1 can be used, and the air-fuel ratio controllability is improved. The obtained evaporated fuel can be estimated with high accuracy, and for example, if a three-way catalyst is used, the purification efficiency of the exhaust gas is also improved.

[0098] The present invention is, lambda using .lamda.o ₂ sensor =
1 may not include the O ₂ feedback control, and may include a unit that performs feedback control using a so-called linear O ₂ sensor so as to converge on an air-fuel ratio leaner than λ = 1.

When the output demand of the vehicle is small, (F
≠ 1) By controlling the air-fuel ratio leaner than λ = 1, even in an engine in which the stratified fuel region is set and the operation period at λ = 1, that is, the estimated period of the purged fuel vapor is short, The estimation period T1 of the evaporated fuel amount can be secured.

Further, by correcting the opening degree PG of the purge control valve 65 from the estimated amount of evaporated fuel EV, the opening degree of the purge control valve can be properly opened to suppress the release of the adsorbed evaporated fuel to the atmosphere.

The present invention can be applied to a modification or modification of the above embodiment without departing from the gist of the invention.

This embodiment is applicable not only to a direct injection gasoline engine but also to a direct injection diesel engine.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a mechanical configuration of a hybrid vehicle according to an embodiment.

FIG. 2 is a diagram showing an engine mounted on the hybrid vehicle.

FIG. 3 is a diagram illustrating control of an engine, a motor, and an automatic transmission in a main state of the hybrid vehicle.

FIG. 4 is a block diagram showing an electrical configuration of the hybrid vehicle according to the embodiment.

FIG. 5 is a flowchart showing overall control of the hybrid vehicle according to the embodiment.

FIG. 6 is a flowchart showing details of engine control.

FIG. 7 is a flowchart showing details of engine control.

FIG. 8 is a flowchart showing details of control of a purge control valve.

FIG. 9 is a view showing a low-speed low-load map of the engine of the embodiment.

FIG. 10 is a diagram showing a fuel injection mode in a stratified combustion region.

FIG. 11 is a diagram showing a fuel injection mode in a uniform combustion region.

FIG. 12 is a diagram showing a fuel injection mode in a rich region.

FIG. 13 is a diagram in which a relationship among a vehicle speed, an accelerator opening, and an output required torque of the vehicle is mapped.

FIG. 14 is a diagram showing a high-speed high-load map of an engine operated when evaporating fuel is estimated according to the present embodiment.

FIG. 15 is a diagram in which the relationship between the engine speed, the required output torque of the vehicle, and the engine torque is mapped.

FIG. 16 is a diagram showing a shift map of the automatic transmission according to the vehicle speed and the accelerator opening.

FIG. 17 is a diagram in which the relationship between engine torque and throttle valve opening is mapped.

FIG. 18 is a diagram in which a relationship among an engine speed, an intake air amount, a basic fuel injection amount, and an ignition timing is mapped.

FIG. 19 is a diagram in which the relationship between the air-fuel ratio and the purge control valve opening is mapped.

FIG. 20 is a diagram in which the relationship between the estimated value of the evaporated fuel amount and the correction value of the opening degree of the purge control valve is mapped.

FIG. 21 is a time chart showing an operation correlating a vehicle speed, a vehicle output required torque, an air-fuel ratio, an actual amount of evaporated fuel, an estimated value of the amount of evaporated fuel, and a purge control valve opening.

FIG. 22 is a time chart showing the correlated operations of the actual amount of evaporated fuel, the air-fuel ratio, the feedback value, the estimated value of the amount of evaporated fuel, and the opening degree of the purge control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Motor 3 Automatic transmission 4 Clutch 5 Battery 6 Inverter

Continued on the front page (72) Inventor Akihiro Kobayashi 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda F-term (reference) 3G044 AA04 AA05 AA10 BA03 BA28 CA03 CA05 CA06 CA08 CA16 CA18 DA02 EA03 EA12 EA19 EA23 EA35 EA50 EA62 EA67 FA10 FA13 FA20 FA27 FA28 FA29 FA30 FA32 GA02 GA08 GA11 GA22 GA23 GA27 3G301 HA01 HA04 HA06 HA10 HA13 HA14 HA16 HA17 JA04 LA03 LA04 LA05 LB04 LC01 LC03 MA01 MA12 MA19 NC02 ND01 NE14 PA01Z PA11A PA11Z PD02Z PD02Z01 PD02Z PD02Z

Claims (5)

[Claims] An engine and / or a motor for driving wheels; a motor control means for controlling an output of the motor; a steam fuel path for communicating the fuel tank with an intake passage of the engine via a barge valve; Purge control means for controlling an opening degree of the purge valve so as to supply the fuel vapor in the fuel tank to the intake passage; and an air-fuel ratio of an air-fuel mixture taken into a combustion chamber of the engine converges to a predetermined air-fuel ratio. An air-fuel ratio control unit that controls the air-fuel ratio control unit to open the purge valve during the control by the air-fuel ratio control unit, and controls a relationship between the related value of the actual air-fuel ratio and the related value of the predetermined air-fuel ratio while the purge valve is opened. An estimating unit for estimating the amount of fuel vapor based on the difference, wherein the air-fuel ratio control unit is configured to adjust the air-fuel ratio to the predetermined air-fuel ratio when the output demand of the vehicle is large. The estimating means estimates the amount of evaporated fuel, and the motor control means, when the output demand of the vehicle is large, calculates the relevant value of the motor output from the relevant value of the output demand of the vehicle. A control device for a vehicle, wherein the motor output is controlled to substantially match a value obtained by subtracting a related value of an engine output controlled by a fuel ratio control means. 2. The air-fuel ratio control unit according to claim 1, wherein the air-fuel ratio control means controls the air-fuel ratio so that the air-fuel ratio alternately changes rich or lean based on the stoichiometric air-fuel ratio when the output demand of the vehicle is large. The control device for a vehicle according to any one of the preceding claims. 3. The vehicle control device according to claim 1, wherein the air-fuel ratio control means controls the air-fuel ratio leaner than the predetermined air-fuel ratio when the output demand of the vehicle is small. . 4. The vehicle according to claim 1, wherein the purge control unit controls the purge valve based on the amount of fuel vapor estimated by the estimating unit. Control device. 5. The air-fuel ratio control means controls the air-fuel ratio leaner than the predetermined air-fuel ratio when the output demand of the vehicle is large, and based on the fuel vapor amount estimated by the estimation means. 5. The system according to claim 4, wherein the purge valve is controlled when the air-fuel ratio is set to lean.
3. The control device for a vehicle according to claim 1.