JPH05222966A - Operation condition control device for hybrid vehicle - Google Patents

Abstract

PURPOSE:To provide an operation condition control device for a hybrid vehicle which can remarkably reduce an exhaust amount of air pollutant. CONSTITUTION:An operation condition control device for a hybrid vehicle 1 is structured so as to selectively or simultaneously performing an engine driving where rear wheels 4 are driven by means of an engine 2 and an electric driving where the rear wheels 4 are driven by means of an electric unit 3. The electric driving is selected in cold running, while the engine driving is selected in warm running. When a running load is a specified value or higher in the warm running, the engine driving is assisted by the electric driving. The electric unit 3 can perform power generation, and is connected constantly to a propeller shaft 16 extended from an axle of the rear wheels 4. The engine 2 is connected to the propeller shaft 16 through a clutch 18 which is set OFF in the cold running.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle in which engine driving and electric driving can be selectively or simultaneously performed, and in particular, the emission amount of air pollutants emitted from the engine can be reduced. The present invention relates to an operating state control device.

[0002]

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

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

On the other hand, conventionally, various hybrid vehicles have been proposed in which engine driving and electric driving are selectively or simultaneously performed. By adopting the three-way catalyst in this hybrid vehicle, it can be expected that the air pollutants will be significantly reduced.

[0005]

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

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to provide a driving state control device for a hybrid vehicle capable of significantly reducing the emission amount of air pollutants.

[0007]

According to a first aspect of the present invention, there is provided a hybrid vehicle in which engine driving for driving driving wheels by an engine and electric driving for driving driving wheels by an electric motor are selectively or simultaneously performed. In the operating state control device, a drive control unit that selects electric drive during cold running, selects engine drive during warm running, and assists engine drive by electric drive when the running load is equal to or greater than a predetermined value during warm running It is characterized by having.

According to a second aspect of the present invention, in the hybrid vehicle driving state control device, the electric motor is capable of generating electric power, and is constantly connected to a drive shaft connected to the axles of the drive wheels, and the engine is a clutch. It is characterized in that a clutch control means is provided which is connected to the drive shaft via the above and which turns off the clutch during a cold operation.

Here, the term "during cold running" in the present invention means, for example, a state in which engine cooling water temperature is 60 ° C. or lower until completion of warming up, or a catalyst temperature is in inactive state, for example, 300 ° C. or less.

[0010]

The present three-way catalytic converter used in automobiles works most effectively when the air-fuel mixture supplied to the engine is in the vicinity of the stoichiometric air-fuel ratio, and at a predetermined temperature (about 350 ° C).
When it is heated above the above, it fully exhibits its catalytic function. However, since the combustion state of the engine is likely to become unstable during the cold running, the air-fuel mixture supplied to the engine is set to a state richer than the theoretical air-fuel ratio, and the catalyst temperature is lower than the predetermined temperature. Therefore, the purifying ability of the catalyst is insufficient during this cold running.

Therefore, according to the first aspect of the present invention, the electric drive is selected during cold running and the engine drive is selected during warm running, so the exhaust gas amount itself becomes extremely small during cold running with insufficient catalyst function, and When the engine is driven with a large amount of exhaust gas, the catalytic function is sufficiently exerted, and as a result, the air pollutants as a whole can be significantly reduced.

If the running load exceeds a predetermined value during warm-up running, electric driving is used in addition to engine driving, so that the required running capacity can be secured.

According to the second aspect of the present invention, the electric motor is always connected to the drive shaft, while the engine is disengaged from the drive shaft by the clutch during cold running.
The electric motor does not drive the engine during cold running,
Therefore, the load on the electric motor does not become excessive.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views for explaining a drive control device for a hybrid vehicle according to an embodiment of the present invention.
Is a schematic configuration diagram of a hybrid vehicle equipped with the device of the present embodiment, FIG. 2 is a schematic configuration diagram of the device of the present 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 the regulation value of the valve opening degree, and FIG. 5 is a diagram showing the regulation value of the opening speed of the throttle valve.

In FIGS. 1 and 2, reference numeral 1 is a hybrid vehicle equipped with a gasoline engine 2 and an electric motor 3 having a power generation function. The engine 2 drives the rear wheel 4 and the electric motor 3 drives the rear wheel. It is configured such that the electric drive for driving the motor 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 arranged. 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 is almost not extended when a normal accelerator depression operation is performed, and the operation can be transmitted to the throttle valve 6 as it is, and is extended when the opening degree of the throttle valve 6 is regulated from the outside. It is set so that it does not hinder the subsequent stepping operation. Reference numeral 11 is a pressure sensor that detects the intake passage negative pressure, and 36 is an accelerator opening sensor that detects the amount of depression of the accelerator pedal 10.

A three-way catalytic converter 13 is provided in the exhaust passage 12 connected to the engine 2.
The converter 13 uses carbon monoxide (CO) in the exhaust gas.
And oxidation of hydrocarbons (HC) and nitrogen oxides (NOx)
It is intended to carry out the reduction of at the same time. In addition, 14 is a catalyst temperature sensor that detects the catalyst temperature, 19 is a water temperature sensor that detects the cooling water temperature of the engine, and 20 is a rotation speed sensor that detects the engine rotation speed.

Here, the purification characteristic of the three-way catalytic converter 13 largely changes depending on the air-fuel ratio of the air-fuel mixture supplied to the engine. For example, the thinner the air-fuel ratio, the more active the oxidizing action and the less reducing action, and the thicker the air-fuel ratio, the opposite.
And when this oxidation and reduction are balanced (around the stoichiometric air-fuel ratio), it works most effectively. Further, the three-way catalytic converter 13 fully 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, and is connected to the rear wheel 4 via a differential 17. The clutch 18 of the automatic transmission 15 is
Normally, the engine output is transmitted to the transmission 15 as in the case of a general fluid converter type, 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 the belt 23, and thus is always connected to the propeller shaft 16. Further, the electric motor 3 is connected to a battery 26 via an inverter switch 24 and a diode 25 which are 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 driven.
Serves as a drive source for driving the rear wheels 4. In addition, the above electric motor 3
Serves as a generator when the clutch 18 is on (connected), the engine speed is higher than a predetermined value, and when the vehicle is decelerated, and the generated power is the diode 2
It is supplied to the battery 26 via the battery 5.

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

Reference numeral 30 denotes a valve opening speed regulating device for regulating the valve opening speed of the throttle valve 6, which is a cylinder 31 containing a piston 31a and the piston 3 of the cylinder 31.
A circulation passage 32 that circulates the hydraulic oil from one chamber defined by 1a to the other chamber. The rod of the piston 31a is in contact with the arm 7 of the throttle valve 6. Further, in the circulation passage 32, a check valve 33 that allows only the movement of the piston 31a to the right in the drawing (the closing direction of the throttle valve 6) is free, and a moving speed to the left in the drawing (the opening speed of the throttle valve 6). A flow rate adjusting valve 34 for adjusting the flow rate is provided.

Reference numeral 35 denotes a CPU for controlling the engine operating state.
Which is the sensor 11, 19, 20, 14,
Intake pressure signal a, water temperature signal b, rotation speed signal c from 36,
The catalyst temperature signal d and the accelerator opening signal e are input to the clutch 18, the automatic transmission 15, the inverter switch 2
4, drive signals AE are output to the pulse motor 29 and the flow rate adjusting valve 34, respectively.

Next, the function and effect of this embodiment will be described. In the vehicle 1 of the present embodiment, as shown in FIG. 3, engine driving for driving the rear wheels 4 by the gasoline engine 2 and electric driving for driving the electric motor 3 are selectively or simultaneously performed.

For example, when the water temperature and the catalyst temperature are low and the load is low (region A in FIG. 3), only 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 the speed stage corresponding to the vehicle speed by the drive signal B, and the opening regulation signal D to the opening regulation device 27 is the fast idle. The opening (see T1 in FIG. 4) is reached, and the speed control signal E to the valve opening speed control device 30 is reached.
Becomes zero speed (see T1 in FIG. 5), and the drive signal C
Thus, the inverter switch 24 sets the electric power to the electric motor 3 to a value according to the required vehicle speed and the like.

As a result, the pulse motor 29 rotates the cam stopper 28 to the first idle opening position, and the flow rate adjusting valve 34 closes the circulation passage 32. Therefore, the throttle valve 6 is restricted to the fast idle opening degree and 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 warming up in the idle state. In this case, the inverter switch 24 adjusts the electric power to the electric motor 3 by the drive signal C according to the depression amount and speed of the accelerator pedal 10, and the vehicle runs only by electric drive. In this case, the clutch 1
Since 8 is 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 region B, and only electric drive is performed. However, in this region, the throttle valve opening and the valve opening speed are larger than those in the above region A, and the speed is faster (T2 portion in FIGS. 4 and 5).
Regulated by. On the other hand, under this temperature condition, medium load (region C)
Then, the clutch 18 is turned on, and engine driving and electric driving are performed in combination.

When the water temperature rises further (Figs. 4 and 5)
(T3 part of)) It is determined that the warm-up is completed, and the restriction of the throttle valve opening degree and the valve opening speed is released. In this temperature state and under low load 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, the electric motor 3 is rotationally driven by the engine, functions as a generator, and the generated electric power passes through the diode 25 to charge the battery 26. Furthermore, under the temperature condition of T3 and under high load, engine driving and electric driving are performed in combination.

When the vehicle is decelerated while 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 power, and as a result, braking force is generated.

Further, although not shown in the figure, in the transient operation range in which the operation range changes from the low load range to the medium load range or the high load range, the throttle valve opening degree is changed even after the warm-up is completed. The opening is regulated to a value smaller than full open during transition. This regulated opening degree is set to a gradually larger value according to the progress of warming up of the engine. The same applies to the opening speed of the throttle valve.

As described above, in this embodiment, the electric drive for driving the rear wheels 4 is selected only by the electric motor 3 during cold running, and the opening of the throttle valve 6 is restricted to the fast idle opening. The amount of exhaust gas is kept extremely small. Therefore, even if 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 amount corresponding to the reduction of the exhaust gas amount itself.

Further, during cold running when the engine speed is held at idle speed, the clutch 18 disconnects the engine 2 from the electric motor 3, so that the electric motor 3 during cold running.
Does not drive the engine, and it is possible to avoid an excessive load on the electric motor 3. Even when the engine is driven, the clutch 18 is turned off during deceleration, and the electric motor 3 is rotationally driven without applying the engine brake. Therefore, it is possible to perform dynamic braking during deceleration and improve the fuel consumption rate.

Further, when the load is high during warm-up running, electric driving is performed in addition to engine driving, so that the required vehicle driving capacity can be secured.

[0034]

As described above, according to the operation state control device for a hybrid vehicle of the invention of claim 1, since the electric drive is selected during cold running and the engine drive is selected during warm running, the catalytic function is improved. The exhaust gas amount itself becomes extremely small during insufficient cold running, and the catalytic function is sufficiently exerted when the engine is driven with a large amount of exhaust gas, resulting in the effect of significantly reducing the air pollutants as a whole. Also, when the running load exceeds a predetermined value during warm-up running, electric drive is used in addition to engine drive,
This has the effect of ensuring the required running capacity.

According to the second aspect of the present invention, the electric motor is always connected to the drive shaft of the axle, while the clutch is disengaged from the drive shaft during cold running of the engine. Therefore, the electric motor drives the engine during cold running. Therefore, there is an effect that the burden on the electric motor can be avoided.

[Brief description of 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 showing a hybrid vehicle including the apparatus of the embodiment.

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

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

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

[Explanation of symbols]

 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)

Claims (2)

[Claims] 1. A driving state control apparatus for a hybrid vehicle, wherein an engine drive for driving a drive wheel by an engine and an electric drive for driving a drive wheel by an electric motor are selectively or simultaneously performed. Is selected, and engine drive is selected during warm-up running, and drive control means for assisting the engine drive by electric drive when the running load is equal to or greater than a predetermined value during warm-up running is provided. Hybrid vehicle driving state control device. 2. A driving state control device for a hybrid vehicle, wherein an engine drive for driving a drive wheel by an engine and an electric drive for driving a drive wheel by an electric motor can be selectively or simultaneously performed. Is capable of generating electricity, and is always connected to a drive shaft connected to the axle of the drive wheels, and the engine is connected to the drive shaft via a clutch, and clutch control means is provided for turning off the clutch during cold operation. A hybrid vehicle driving condition control device.