JPH09224304A - Hybrid automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automobile which charges a surplus output to a battery and uses it as a source for driving a generator by operating an internal engine in an improved fuel consumption. SOLUTION: An automobile has two systems of power supplies, namely an internal engine 2 and generators 8 (8a and 8b). One of front and rear drive wheels 9 (9a and 9b) and 10 (10a and 10b) is driven by the internal engine 2 and at the same time the other is driven by the generators 8, generator individual operation, internal engine individual operation, and simultaneous operation of the generator and the internal engine is selected properly according to the size of requested load on driving, and the internal engine 2 is operated by a constant speed that indicates its best fuel consumption point. A battery 1 is charged by performing generation with the output surplus when operating the internal engine individually and a shortage is added by operating the generators 8 due to the power of the battery 1 when the above requested load exceeds torque at the best fuel consumption point of the internal engine 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called electric vehicle that runs on electric power, and more particularly to a hybrid vehicle that obtains driving force from an electric motor and an internal combustion engine.

[0002]

2. Description of the Related Art A vehicle which obtains driving force from an electric motor and an internal combustion engine is a SAE Technical Paper 910.
It is known as shown at 247.

[0003]

SUMMARY OF THE INVENTION In the above-mentioned known technique,
It cannot be said that the efficiencies of the electric motor and the internal combustion engine are fully utilized, and there is room for improvement in terms of efficiency improvement.

The invention is aimed in particular at increasing the efficiency of internal combustion engines.

[0005]

[Means for Solving the Problems] In order to achieve the above objects, the following structure is adopted.

In a hybrid vehicle having two power sources, an internal combustion engine and an electric motor, one of the front and rear drive wheels is driven by the internal combustion engine and the other is driven by the electric motor to meet the required load during running. Then, the electric motor alone operation, the internal combustion engine independent operation, and the simultaneous operation of the electric motor and the internal combustion engine are appropriately selected, and the internal combustion engine is operated at a constant rotation speed that indicates the best fuel efficiency.

Further, when the internal combustion engine alone operates to generate electric power with its output surplus to charge the battery, and the required load exceeds the torque at the best fuel efficiency point of the internal combustion engine, the shortage is battery-powered electric motor. Add by driving.

[0008]

FIG. 1 shows an embodiment of the present invention.
Here, 1 is a battery, 2 is an internal combustion engine, 3 is a generator, 4 is a first clutch, 5 is a second clutch, 6 is a continuously variable transmission, 7 is a differential, 8 is an electric motor, 9 is front wheels, 10 is A rear wheel, 11 is a gear, and 12 is a control circuit.

The torque of the internal combustion engine 2 is supplied to the continuously variable transmission 6 via the first clutch 4 and the second clutch 5 and to the rear wheels 10a, 10b via the differential 7. When the torque of the internal combustion engine 2 is larger than the required driving force, the generator 3 is driven through the gear 11 to be converted into electricity and stored in the battery 1. Further, the electric power of the battery 1 drives the electric motors 8a and 8b and the front wheels 9a and 9b. As described above, in this embodiment, the front wheels are electric and the rear wheels are internal combustion engines, but the drive sources for the front wheels and the rear wheels may be changed.

Further, the control circuit 12 absorbs the surplus output of the internal combustion engine 2 by the generator 3 so that the internal combustion engine 2 can be operated under the condition where the fuel consumption is optimum. When the drive torque of the internal combustion engine 2 is insufficient, the electric power of the battery 1 is used to operate the electric motor 8 to compensate for the insufficient torque. Further, when the vehicle speed becomes high and the best fuel consumption condition cannot be maintained at the gear ratio of the continuously variable transmission 6, the second clutch 5 is opened to drive only the electric motor 8, and the output of the internal combustion engine 2 is set to the generator 3. It is supplied to the battery 1 and the electric motor 8 via the.

When a larger torque is required at a high vehicle speed, the second clutch 5 is reconnected to transmit the torque of the internal combustion engine to the rear wheels to make up for the insufficient torque of the electric motor 8. At this time, the best fuel economy operation of the internal combustion engine 2 is canceled.

FIG. 2 shows an example of selecting the operation mode depending on the magnitude of the required load. First step 10
The required load P is calculated at 1. The required load P is obtained by adding a load necessary for traveling and a charging (including electric motor load) load. Next, at step 102, the required load P and the set load P
Compare 1 Here, it is desirable that P1 is the load at the best fuel economy point of the internal combustion engine, but even if the load is other than that, the fuel economy of the internal combustion engine will be somewhat lowered, but it is established.

In the comparison in step 102, when the required load P exceeds the set load P1 and is considerably smaller than a predetermined value, that is, when the required load P at the present time has not yet reached the fuel consumption best point load P1 of the internal combustion engine. It is not necessary to operate the internal combustion engine from the viewpoint of fuel economy, and the electric motor can be operated independently (step 104).

If P is not so smaller than P1 in the comparison of step 102 (does not exceed the constant value), P and P1 are compared again (step 103), and the required load P is greater than the set load P1. If it is slightly smaller, the internal combustion engine is operated in step 105, and if it is larger, the electric motor and the internal combustion engine are simultaneously operated. Here, regarding the required load P, the running load cannot be changed, but the charging load can be adjusted by the charge amount of the battery. That is, when the battery voltage is sufficiently high and the charging current to the battery is small, the charging load is small, and conversely, when the battery voltage is low, the charging load is large. .

Therefore, in step 103, when P is slightly smaller than P1, the internal combustion engine is in operation. At this time, the internal combustion engine is operating at the fuel efficiency best point, and the running load does not reach P1. However, it can be supplemented with a large charging load. Then, as the charging is continued, the charging load becomes gradually smaller, but until then, the internal combustion engine can be operated independently, and the opportunities for internal combustion engine independent operation can be increased.

When the running load increases and the required load P increases to a level that cannot be compensated for by the charging load, the internal combustion engine and the electric motor are simultaneously operated in step 103. When operating the internal combustion engine and the electric motor at the same time, the traveling speed is determined by the rotational speed of the electric motor, and the internal combustion engine adjusts the gear ratio so that the rotational speed is at the best fuel consumption point.

FIG. 3 shows the operating mode of the internal combustion engine. In step 110, the traveling speed N is calculated, and in step 111, it is compared with the set value N1, and when N is smaller than N1, the vehicle is driven at a constant rotation speed which is the rotation speed at the best fuel economy point. The gear ratio at that time should be minimized from the viewpoint of fuel consumption. Then, even if the traveling speed N becomes high, by adjusting the gear ratio, it is possible to continue driving at a constant rotation speed that is the best fuel economy point. Further, the set value N1 is preferably a speed determined by the minimum gear ratio and the rotation speed of the fuel efficiency best point of the internal combustion engine, but even if the setting value N1 is changed a little, the fuel consumption is slightly lowered.

When the traveling speed N exceeds the set value N1 beyond the adjustment limit of the gear ratio (step 111)
Therefore, it is naturally possible to change the rotation speed of the internal combustion engine in accordance with the vehicle speed beyond the rotation speed of the best fuel economy point (step 113).

FIG. 4 shows the relationship between the rotational speed of the internal combustion engine and the torque. The equal fuel consumption lines connect the values showing the same fuel consumption characteristics, and there are zones where the fuel consumption is the best. From FIG. 4, it is impossible to maintain the best fuel economy zone in a region where the rotation speed of the internal combustion engine is high. Therefore,
Particularly in a region of high vehicle speed, it is necessary to increase the rotational speed of the internal combustion engine for traveling even if the gear ratio is fixed to the minimum value.
This makes it possible to obtain a large torque without using a coexisting electric motor having a large capacity.

Similar to the above, as can be seen from FIG. 4, if the internal combustion engine is operated when the traveling speed is low, the fuel efficiency best point cannot be maintained. In that case, either the internal combustion engine is stopped or the The second clutch 5 of No. 1 can be opened and used only for power generation. In this case, it is necessary to consider the charge amount of the battery.

When the traveling load is small, the internal combustion engine is not used at low speed because it is driven only by the electric motor.
Therefore, it is possible to shift the gear ratio to a smaller one than the conventional device.

Further, the deceleration operation will be achieved by utilizing the engine braking effect without supplying fuel to the internal combustion engine during deceleration in the motor alone operation. Further, at the time of deceleration of the independent operation of the electric motor, the first clutch on the internal combustion engine side is opened, the second clutch on the wheel side is connected, and the regenerative brake is generated by the generator interposed between the first clutch and the second clutch. It can also be achieved by making a motion.

FIG. 5 shows another embodiment of the present invention. The present invention is a case where an electric motor is added to each of the four wheels. Although the configuration in which the diff 7 is added is shown in FIG. 5, the diff 7 can be eliminated when the differential action is performed by the electric motor.

FIG. 6 shows another embodiment of the present invention. There are two drive wheels, and either front wheels or rear wheels are possible.
The generator 3 is directly connected to the internal combustion engine 2. The differential action of the left and right drive wheels is performed by the electric motor 8. A clutch (not shown) is arranged between the internal combustion engine and the continuously variable transmission.

FIG. 7 shows another embodiment of the present invention.
A clutch 4 is interposed between the internal combustion engine 2 and the continuously variable transmission 6. The electric motor is a combined type of the electric motor / generator 13. When the output of the internal combustion engine exceeds the required driving force, the electric motor 13 becomes a generator and charges the battery 1.
In this way, one generator 3 can be omitted.

FIG. 8 shows another embodiment of the present invention.
Similar to FIG. 7, the electric motor 13 is a combined electric motor / generator type.

[0027]

According to the present invention, since the internal combustion engine is provided side by side, the traveling distance can be increased and the driving torque during acceleration can be increased without increasing the capacity of the battery.

By properly using the electric motor and the internal combustion engine, only the electric motor can be operated in a place where exhaust gas is disliked, and only the internal combustion engine can be operated in a place where exhaust gas regulations are relatively loose.

Further, the driving forces of the electric motor and the internal combustion engine can be supplied to different driving wheels to operate the internal combustion engine in a relatively fuel-efficient state. Further, when the driving force of the internal combustion engine is excessive, the power can be generated, the excess torque can be absorbed and stored in the battery, and the efficiency of the internal combustion engine can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a flowchart for determining a driving mode.

FIG. 3 is a flowchart for determining the rotational speed control of the internal combustion engine.

FIG. 4 is a characteristic diagram showing the relationship between the rotational speed and the torque of the internal combustion engine.

FIG. 5 is a configuration diagram of another embodiment of the present invention.

FIG. 6 is a configuration diagram of another embodiment of the present invention.

FIG. 7 is a configuration diagram of another embodiment of the present invention.

FIG. 8 is a configuration diagram of another embodiment of the present invention.

[Explanation of symbols]

 1 Battery 2 Internal Combustion Engine 3 Generator 4 First Clutch 5 Second Clutch 6 Continuously Variable Transmission 7 Differential 8 Electric Motor 9 Front Wheel 10 Rear Wheel 11 Gear 12 Control Circuit 13 Electric Motor / Generator

Claims (9)

[Claims] 1. In a hybrid vehicle having two power sources of an internal combustion engine and an electric motor, one of the front and rear drive wheels is driven by the internal combustion engine and the other is driven by the electric motor, so that the required load for running is reduced. Correspondingly, the electric motor alone operation, the internal combustion engine independent operation, and the simultaneous operation of the electric motor and the internal combustion engine are appropriately selected, and the internal combustion engine is operated at a constant rotation speed that indicates the best fuel efficiency. Hybrid car to do. 2. In a hybrid vehicle having two power sources of an internal combustion engine and an electric motor, one of the front and rear drive wheels is driven by the internal combustion engine and the other is driven by the electric motor, so that the required load during traveling is reduced. Correspondingly, the electric motor alone operation, the internal combustion engine independent operation, and the simultaneous operation of the electric motor and the internal combustion engine are appropriately selected, and the internal combustion engine is operated at a constant rotation speed that indicates the best fuel economy, When the required load exceeds the torque at the fuel efficiency best point of the internal combustion engine to generate power with the output surplus at times, the shortage is added by the battery-powered motor operation. Hybrid car. 3. The hybrid vehicle according to claim 1 or 2, characterized in that, during deceleration in an electric motor alone operation, fuel is not supplied to the internal combustion engine, and the engine braking effect is utilized. 4. The method according to claim 1 or 2, wherein during deceleration of the electric motor alone operation, the first clutch on the internal combustion engine side is disengaged, the second clutch on the wheel side is connected, and the first clutch and the second clutch are connected. A hybrid vehicle characterized by a regenerative braking operation by a generator interposed therebetween. 5. A hybrid vehicle having two power sources of an internal combustion engine and an electric motor, wherein an electric motor is installed on each of the front and rear drive wheels, and the output of the internal combustion engine is added to one of the rear wheels or the front wheels to make the vehicle running. Depending on the required load, the electric motor alone operation, the internal combustion engine independent operation, and the simultaneous operation of the electric motor and the internal combustion engine are appropriately selected. A hybrid vehicle characterized by being driven. 6. A hybrid vehicle having two power sources, an internal combustion engine and an electric motor, wherein one of front and rear drive wheels is driven by the internal combustion engine and an electric motor is installed on the other, and the differential operation of the left and right wheels is performed by the electric motor. Depending on the required load during driving, the electric motor alone operation, the internal combustion engine independent operation, and the electric motor and internal combustion engine simultaneous operation are appropriately selected. The hybrid vehicle is characterized in that it is driven at a constant rotational speed. 7. A hybrid vehicle having a dual power source of an internal combustion engine and an electric motor, wherein one of front and rear drive wheels is driven by the internal combustion engine and the other is driven by a combined type of the electric motor and the generator. Depending on the magnitude of the required load, the electric motor alone operation, the internal combustion engine independent operation, and the simultaneous operation of the electric motor and the internal combustion engine are appropriately selected, and the internal combustion engine is operated at a constant rotation speed that shows the best fuel consumption. A hybrid vehicle characterized in that, when the internal combustion engine is operated independently, the output surplus is generated by the generator to charge the battery. 8. A hybrid vehicle having two power sources, an internal combustion engine and an electric motor, wherein one of the front and rear drive wheels is driven by the internal combustion engine and the other is driven by the electric motor to reduce the required load during traveling. Correspondingly, the electric motor alone operation, the internal combustion engine independent operation, and the simultaneous operation of the electric motor and the internal combustion engine are appropriately selected, and the internal combustion engine is operated at a constant rotation speed that indicates the best fuel economy, A hybrid vehicle characterized in that the range of the operating speed of the internal combustion engine can be applied to a high traveling speed by shifting the gear ratio of the transmission interposed between the two to a smaller one. 9. The hybrid vehicle according to claim 1 or 2, wherein the internal combustion engine is capable of varying its rotational speed outside a constant rotational speed that indicates its fuel efficiency best point.