JP3046444B2 - Operating state control device for hybrid vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle capable of selectively or simultaneously driving an engine and an electric drive, and more particularly to reducing the amount of air pollutants discharged from an engine. The present invention relates to an operating state control device as described above.

[0002]

2. Description of the Related Art Recently, it has been demanded to greatly reduce air pollutants emitted from automobiles. For example, regulation of the Ultra Low Emission Vehicle (ULEV) in the United States requires that the amount of hydrocarbons (HC) emitted by conventional vehicles be reduced to about 1/10.

In response to such a demand for reducing air pollutants, a three-way catalytic converter has conventionally been employed. This catalyst is for simultaneously oxidizing carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas and reducing nitrogen oxides (NOx).

[0004] On the other hand, various hybrid vehicles that selectively or simultaneously perform engine driving and electric driving have been proposed. By employing the three-way catalyst in this hybrid vehicle, it is expected that the air pollutants will be significantly reduced.

[0005]

In order to further reduce the above-mentioned air pollutants in the above-mentioned hybrid vehicle, it is extremely important how to select and use an engine drive and an electric drive. Conceivable. However, this point has not been proposed so far.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and has as its object to provide an operating state control device for a hybrid vehicle capable of greatly reducing the amount of air pollutants emitted.

[0007]

According to a first aspect of the present invention, there is provided a hybrid vehicle in which engine driving for driving the driving wheels by an engine and electric driving for driving the driving wheels by an electric motor are performed selectively or simultaneously. In the operation state control device, during cold running when the cooling water temperature is lower than a predetermined value, only the electric driving is performed at a low load, and the electric driving is assisted by the engine driving at a medium load. The engine is warmed up by regulating the throttle valve opening and opening speed to a large value. When the engine is running after warming up when the cooling water temperature is higher than the specified value, only the engine is driven at low and medium loads, and only at high loads. Is characterized by having a drive control means for assisting the engine drive by electric drive.

[0008]

[0009] In the present invention, the term "during cold running" refers to a running state until the completion of warm-up when the temperature of the engine cooling water is, for example, 60 ° C or lower, and "during running after warm-up" refers to a running state after completion of warm-up. .

[0010]

The three-way catalytic converter employed in the current automobile works most effectively when the air-fuel mixture supplied to the engine is near the stoichiometric air-fuel ratio, and has a predetermined temperature (about 350 ° C.).
When heated above, the catalyst function is fully exhibited. However, during the cold running, the air-fuel mixture supplied to the engine is set to be richer than the stoichiometric air-fuel ratio because the combustion state of the engine tends to be unstable, and the catalyst temperature is lower than the predetermined temperature. Therefore, during this cold running, the purification ability of the catalyst is insufficient.

Therefore, in the first aspect of the present invention, the electric drive is selected during the cold running, and the valve opening and the opening speed are regulated to be larger as the cooling water temperature is higher, so that the engine is warmed up and the running after the warming up is performed. When the engine is driven at times, the engine can be warmed up in a short time while the amount of exhaust gas itself is extremely small during cold running when the catalyst function is insufficient, and the catalyst function is sufficient when the engine is driven with a large amount of exhaust gas. As a result, air pollutants as a whole can be significantly reduced.

When the running load exceeds a predetermined value during running after warm-up, electric driving is used in addition to engine driving, so that necessary driving performance can be secured.

[0013]

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 5 are views for explaining a drive control device for a hybrid vehicle according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a hybrid vehicle equipped with the device of the embodiment, FIG. 2 is a schematic configuration diagram of the device of the embodiment, FIG. 3 is a map diagram showing selection and combined use of engine drive and electric drive, and FIG. FIG. 5 is a diagram showing a regulation value of the valve opening degree, and FIG. 5 is a diagram showing a regulation value of the opening speed of the throttle valve.

1 and 2, reference numeral 1 denotes a hybrid vehicle provided with a gasoline engine 2 and a motor 3 having a power generating function. The hybrid vehicle is driven by an engine that drives a rear wheel 4 by the engine 2 and a rear wheel is driven by the motor 3. 4 can be selectively or simultaneously performed.

In the intake passage 5 connected to the engine 2, a throttle valve 6 for opening and closing the passage 5 is rotatably disposed. The throttle valve 6 is connected to an accelerator pedal 10 via an arm 7, a cable 8, and a spring 9. The spring characteristic of the spring 9 can be transmitted to the throttle valve 6 as it is without any extension when a normal accelerator depressing operation is performed, and can be extended when the opening of the throttle valve 6 is restricted from the outside. It is set so that there is almost no hindrance to the subsequent stepping operation. Reference numeral 11 denotes a pressure sensor for detecting the intake passage negative pressure, and reference numeral 36 denotes an accelerator opening sensor for detecting the amount of depression of the accelerator pedal 10.

In the exhaust passage 12 connected to the engine 2, a three-way catalytic converter 13 is provided.
The converter 13 is provided with carbon monoxide (CO) in exhaust gas.
And hydrocarbon (HC) oxidation and nitrogen oxides (NOx)
For the simultaneous reduction of In addition, 14 is a catalyst temperature sensor for detecting a catalyst temperature, 19 is a water temperature sensor for detecting a cooling water temperature of the engine, and 20 is a rotation speed sensor for detecting the engine rotation speed.

Here, the purification characteristics of the three-way catalytic converter 13 vary greatly depending on the air-fuel ratio of the air-fuel mixture supplied to the engine. For example, as the air-fuel ratio becomes thinner, the oxidizing action becomes more active and the reducing action becomes less active, and as the air-fuel ratio becomes thicker, the reverse occurs.
When the balance between the oxidation and the reduction is achieved (near the stoichiometric air-fuel ratio), it works most effectively. Further, the three-way catalytic converter 13 completely exhibits the catalytic function when it is heated to a predetermined temperature (about 350 ° C.) or higher.

Reference numeral 15 denotes an automatic transmission connected to the output side of the engine 2, the output shaft of which is the propeller shaft 1.
6, is connected to the rear wheel 4 via a differential 17. The clutch 18 of the automatic transmission 15
Normally, similarly to a general fluid converter type, the engine output is transmitted to the transmission 15 and the transmission 15 and the engine 2 can be shut off by an external signal.

The output shaft 21 of the electric motor 3 is connected to the counter shaft 22 of the automatic transmission 15 by a belt 23, and is therefore always connected to the propeller shaft 16. The electric motor 3 is connected to a battery 26 via an inverter switch 24 and a diode 25 connected in parallel with each other. When the clutch 18 is off (disengaged) and when the engine speed is lower than a predetermined value, battery power is supplied to the electric motor 3 via the inverter switch 24, whereby the electric motor 3
Is a drive source for driving the rear wheel 4. In addition, the motor 3
Functions as a generator when the clutch 18 is turned on (connected) and the engine speed is higher than a predetermined value, and when the vehicle decelerates.
5 is supplied to the battery 26.

Reference numeral 27 denotes an opening restricting device for restricting the opening of the throttle valve 6, which is a cam stopper 28 which contacts the arm 7 of the throttle valve 6 and restricts the maximum rotation angle of the arm 7.
And a pulse motor 29 that changes the regulation opening by rotating the cam stopper 28.

Numeral 30 denotes a valve opening speed regulating device for regulating the valve opening speed of the throttle valve 6, which comprises a cylinder 31 having a built-in piston 31a and the piston 3 of the cylinder 31.
And a circulation passage 32 for circulating hydraulic oil from one chamber defined in 1a to the other chamber. The rod of the piston 31a is in contact with the arm 7 of the throttle valve 6. The circulation passage 32 has a check valve 33 that allows only the movement of the piston 31a to the right (in the closing direction of the throttle valve 6) in the drawing, and a moving speed to the left (the opening speed of the throttle valve 6). A flow control valve 34 for adjusting the pressure is provided.

A CPU 35 controls the operating state of the engine.
Which are the above-mentioned sensors 11, 19, 20, 14,
36, an intake pressure signal a, a water temperature signal b, a rotation speed signal c,
When the catalyst temperature signal d and the accelerator opening signal e are input, the clutch 18, the automatic transmission 15, the inverter switch 2
4, drive signals A to E are output to the pulse motor 29 and the flow control valve 34, respectively.

Next, the operation and effect of this embodiment will be described. In the vehicle 1 of the present embodiment, as shown in FIG. 3, an engine disturbance that drives the rear wheels 4 by the gasoline engine 2 and an electric drive that is driven by the electric motor 3 are performed selectively or simultaneously. Here, regions A, B, and C in FIG. 3 and regions T1 and T2 in FIGS.
E and F, and a region T3 in FIGS. 4 and 5 shows a state after traveling after warm-up.

For example, when the water temperature and the catalyst temperature are low and the load is low (region A in FIG. 3), only the electric drive is performed.
In this case, the clutch 18 is turned off by the drive signal A from the CPU 35, the automatic transmission 15 is set to a speed stage corresponding to the vehicle speed by the drive signal B, and the opening restriction signal D to the opening restriction device 27 is fast idle. The opening degree (see T1 in FIG. 4) is reached, and the speed regulation signal E to the valve opening speed regulation device 30
Becomes zero speed (see T1 in FIG. 5), and furthermore, the drive signal C
Accordingly, the inverter switch 24 sets the electric power to the electric motor 3 to a value corresponding to the required vehicle speed and the like.

Thus, the pulse motor 29 rotates the cam stopper 28 to the first idle opening position, and the flow regulating valve 34 closes the circulation passage 32. Therefore, the throttle valve 6 is restricted to the fast idle opening and the zero speed regardless of the depression amount and the depression speed of the accelerator pedal 10, and as a result, the engine 2 waits for warm-up to proceed in an idle state. In this case, the inverter switch 24 adjusts the power to the electric motor 3 by the drive signal C corresponding to the depression amount and the speed of the accelerator pedal 10, and the vehicle runs only by the electric drive. In this case, the clutch 1
Since the motor 8 is turned off, the electric motor 3 does not drive the engine in the idle rotation state.

Even when the water temperature rises and the load is low (region B in FIG. 3), the drive signals A, B, and C are set in the same manner as in the case of region A, and only the electric drive is performed. However, in this region, the throttle valve opening and the valve opening speed are larger than those in the above-mentioned region A, and the speed is faster (T2 portion in FIGS. 4 and 5).
Is regulated. On the other hand, in this temperature condition, medium load (region c)
, The clutch 18 is turned on, and the engine drive and the electric drive are performed in combination.

When the water temperature further rises (see FIGS. 4 and 5).
T3) It is determined that the warm-up is completed, and the restrictions on the throttle valve opening and the valve opening speed are released. In this temperature state and when the load is low and medium load (regions d and e), the power supply to the electric motor 3 is cut off. As a result, only the engine is driven, and the electric motor 3 is rotationally driven by the engine, functions as a generator, and the generated electric power charges the battery 26 through the diode 25. Furthermore, when the temperature is T3 and the load is high, engine driving and electric driving are performed in combination.

When the vehicle is in a deceleration state when the engine is driven, the clutch 18 is turned off. Therefore, the engine brake does not act, and the electric motor 3 is rotationally driven by the inertial force of the vehicle. As a result, the electric motor 3 generates electric power, and as a result, a braking force is generated.

Further, although not shown, in a transitional operation range in which the operation range changes from a low load range to a medium load range, or to a higher load range, the throttle valve opening is maintained even after the warm-up is completed. Regulate the opening during transition to a value smaller than the full opening. The regulation opening is set to a gradually larger value according to the progress of the warm-up of the engine. The same applies to the opening speed of the throttle valve.

As described above, in the present embodiment, the electric drive for driving the rear wheel 4 by only the electric motor 3 during the cold running is selected, and the opening of the throttle valve 6 is regulated to the fast idle opening. Is kept very small. Therefore, even when the catalytic function is insufficient due to the low temperature of the catalytic converter 13 or due to the high air-fuel ratio, the air pollutants can be reduced by the reduced amount of the exhaust gas itself.

During cold running in which the engine rotation is maintained at idle speed, the clutch 18 disconnects the engine 2 from the electric motor 3.
Does not drive the engine, so that the load on the electric motor 3 can be prevented from becoming excessive. Also, when the engine is driven, the clutch 18 is turned off at the time of deceleration, and the electric motor 3 is driven to rotate without applying the engine brake. Therefore, the power generation braking can be performed at the time of deceleration, and the fuel efficiency can be improved.

Further, when the running load becomes equal to or more than a predetermined value during running after warm-up, electric driving is used in addition to engine driving, so that necessary driving performance can be secured.

As described above, according to the operating condition control apparatus for a hybrid vehicle according to the present invention, the electric drive is selected during the cold running, and the valve opening and the opening speed are regulated to be larger as the cooling water temperature is higher. Since the engine is warmed up and the engine drive is selected during running after warming up, the engine can be warmed up in a short time while the amount of exhaust gas itself is extremely small during cold running when the catalytic function is insufficient, and When the engine is driven with a large amount of gas, the catalytic function is sufficiently exhibited, and as a result, there is an effect that the air pollutants as a whole can be significantly reduced. In addition, when the running load becomes equal to or more than a predetermined value during running after warm-up, electric driving is used in addition to engine driving, so that there is an effect that necessary running performance can be secured.

[0035]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a driving state control device for a hybrid vehicle according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a hybrid vehicle including the above-described embodiment device.

FIG. 3 is a map diagram showing selection of an engine drive and an electric drive in the embodiment, and a combined use state;

FIG. 4 is a characteristic diagram showing a regulation value of a throttle valve opening degree of the apparatus of the embodiment.

FIG. 5 is a characteristic diagram showing a regulation value of an opening speed of a throttle valve of the apparatus of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 hybrid vehicle 2 engine 3 electric motor 4 rear wheel (drive wheel) 16 propeller shaft (drive shaft) 18 clutch 35 CPU (drive control means, clutch control means)

Continuation of the front page (56) References JP-A-3-121928 (JP, A) JP-A-58-69403 (JP, A) JP-A-48-46026 (JP, A) JP-A-63-65134 (JP, A) JP-A-58-217748 (JP, A) JP-A-60-30440 (JP, A) JP-A-5-21119 (JP, U) JP-A-2-119944 (JP, U) JP-A 62-74149 (JP, U) Jiko 56-17724 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 29/00-29/06 B60K 6/02 B60L 11 / 00-11/14 F02D 41/00-41/40

Claims (1)

(57) [Claims] 1. A selectively an electric drive for driving the drive wheels by an engine driving an electric motor for driving the drive wheels by an engine, or in the operating condition control apparatus of the hybrid vehicle to perform simultaneously the cooling water temperature is predetermined Value
During cold running, use only the electric drive when the load is low.
In the case of medium load, the electric drive is supplemented by the engine drive.
The greater the cooling water temperature, the larger the throttle valve opening,
The engine is warmed up by regulating the opening speed and the cooling water temperature is
When driving after warm-up higher than the specified value,
Only the engine is driven, and when the load is high, the engine is driven
A driving state control device for a hybrid vehicle, comprising a drive control means for assisting the electric vehicle by electric driving .