JPH11178111A - Hybrid electric car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make low the weight and cost of the system of a hybrid electric vehicle, by making constant the shaft output of its engine (rotational speed) generated substitutionally by its generator in the course of its starting. SOLUTION: While the starting of an engine 4 requires a starter, a generator 5 substitutes it. The control of the generator 5 is performed by a converter 10 to control the current of the primary winding of the generator 5. When starting the engine 4, the generator 5 is driven in a power running way. The load of the generator 5 is increased gradually until the rotational speed of the engine 4 reaches the one of it having thereat a good combustion efficiency. The load of the generator 5 is so adjusted by the converter 10 that the rotational speed of the engine 4 does not overshoot the one of it having thereat a good combustion efficiency. Still, when the engine 4 has no load, the rotational speed of its shaft is made higher than the one of it having thereat a good combustion efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a fuel consumption of 30 km.
The present invention relates to a hybrid electric vehicle aimed at a vehicle that suppresses harmful exhaust gas and suppresses fuel consumption more than a vehicle driven by a reciprocating engine (hereinafter abbreviated as an engine) that can run at / l, and particularly drives a generator. The present invention relates to a high-efficiency operation system of an engine.

[0002]

2. Description of the Related Art Conventionally, the engine itself controls the number of shaft revolutions to determine the amount of power generation. When the battery was almost fully charged, the shaft output of the engine was reduced to reduce the amount of charge. In JP-A-9-224304, one of the front and rear vehicle drive wheels is driven by an electric motor, and the other is driven by an engine.
There has been proposed a method of timely selecting the simultaneous operation of the electric motor and the engine in accordance with the magnitude of the required load during traveling.

An object of the present invention is to control the number of revolutions of an engine by a generator without controlling the opening of a throttle valve of the engine. Accordingly, it is an object of the present invention to provide a hybrid electric vehicle capable of reducing the weight and cost of a vehicle system.

[0004]

The engine must change the magnitude of the shaft output due to the fluctuation of the load. Therefore, a complicated system such as a throttle valve, a throttle sensor and an intake sensor must be employed.

[0005] In the emission countermeasures, it is difficult to respond to a change in the throttle opening in a transient region. Further, it takes time until the catalyst is completely operated, and it is difficult to take measures against exhaust gas for environmental protection.

In the case of driving only by a motor, a large current must be discharged from a battery during acceleration. Therefore, the life of the battery is shortened.

When the vehicle starts or runs uphill, the load on the motor increases. Therefore, the size of the motor increases.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an electric vehicle equipped with a battery and an electric motor required for running a vehicle, and an engine and a generator required for charging the battery. The shaft output by the engine is not limited to the generator drive only. When the required load for driving the vehicle is large, the load by the generator is reduced and the load is applied to the vehicle drive load. And increase the load of the generator by the reduced amount.
As described above, the shaft output of the engine, that is, the rotation speed, is set to be constant when the engine is running. In addition, when the vehicle load is reduced and driving with only the electric motor has higher overall energy efficiency, the shaft load of the engine is limited to the generator.

The engine does not control the throttle opening. Therefore, when the shaft is not loaded, the engine speed is set higher than the engine speed range where the fuel consumption rate is low.

[0010] The engine is stopped until the temperature reaches a temperature at which the catalyst can be completely operated, and when the battery is in a fully charged state or when charging is not necessary. At this time, the vehicle is not driven by the shaft output of the engine.

The transmission of torque from the engine to the driving wheels of the vehicle uses a continuously variable transmission.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. FIG. 1 shows the hybrid electric vehicle 1 developed this time.
The hybrid electric vehicle 1 running with the electric motor 2 driving the vehicle driving wheels 15 (front wheels) is equipped with an engine 4 and a generator 5 to compensate for a decrease in the energy density of the battery 3. In this example, an engine using gasoline as fuel is used as an example. The engine may be a gas engine, a gasoline engine, or a diesel engine. The generator 5 is driven by the shaft output of the engine 4. The generator 5 is preferably an induction motor having excellent maintainability and power conversion efficiency, or a synchronous motor using a permanent magnet.

In order to reduce the weight of the engine 4, the engine 4 has a cooling structure by forced air cooling by an electric fan 6. Engine 4
Since the load is constant, forced air cooling is sufficient. The electric fan 6 is disposed forward of the engine 4 in the vehicle front direction so that heat generated by the engine 4 is released to the rear of the vehicle. The shaft output of the engine 4 is a point where the combustion consumption rate [kg / kWh] is low.
Since the amount of exhaust gas is kept almost constant, the catalyst 7 and the silencer 8 may be smaller than in a conventional gasoline-powered vehicle.

The conventionally mounted throttle valve, throttle sensor, and intake sensor are unnecessary since the throttle opening is constant. The displacement of the engine 4 is 500-8
It should be about 00cc. If the traveling distance per liter of gasoline is 40 km, about 12 liters of the fuel tank 9 is sufficient.

Although a starter is required to start the engine 4, it is covered by the generator 5. In the control of the generator 5, the converter 10 controls the current of the primary winding of the generator 5. When starting the engine 4, the generator 5 is driven by power. The load on the generator 5 is gradually increased until the engine 4 reaches a rotation speed at a point where combustion efficiency is good. The load of the generator 5 is adjusted by the converter 10 so that the rotation speed of the engine 4 does not overshoot from the point of good combustion efficiency. When the engine 4 has no load, the shaft rotation speed is higher than the point of good combustion efficiency.

When the shaft rotation of the engine 4 is zero, the load on the generator 5 is also zero. When the rotation speed of the engine 4 does not fluctuate and the vehicle is driven at low speed and low torque, the power generated by the generator 5 is maximized.

The generator 5 is of a water-cooled type in order to reduce its size, and shields heat from the engine 4 as much as possible. The engine 4 is of a horizontal type with an exhaust pipe directed toward the rear of the vehicle, and a generator 5 is installed on the shaft to extend the output power. The oil lubrication is improved to reduce heat transfer to the generator 5, and an oil cooler is mounted for cooling.

The motor 2 for driving the vehicle rotates according to the accelerator, and the rotating shaft is connected by a gear 16 to drive the wheels. The electric motor 2 is an AC machine, and is driven by converting DC power of the battery 3 into AC power by the inverter 11.
The cooling of the electric motor 2 and the inverter 11 has a water-cooling structure to obtain sufficient drive and to reduce the size. A radiator 12 is provided in front of the vehicle, and the electric motor 2 and the inverter 11 are cooled by the circulation pump 14. At the same time, a water channel is provided toward the generator 5 to cool the motor 2 at the same time.

Next, a method of operating the engine 4 will be described. The engine 4 is not operated more than necessary for labor saving. The engine 4 is stopped when the electric motor 2 is driving the vehicle at low speed and low torque until the battery 3 is fully charged or the catalyst 7 is activated.
When the energy density of the battery 3 is equal to or less than a certain value, or when the vehicle speed or the running load of the vehicle is equal to or more than a certain value, the engine 4 is started and the battery 3 is charged by the generator 5 and the converter 10. At this time, Engine 4
Do not stop frequently and repeat the operation.

When the vehicle load drive by the electric motor 2 increases, a part of the shaft output of the engine 4 is transmitted to the clutch 17 and the continuously variable transmission 13 to drive the vehicle. Regardless of the magnitude of the shaft output to drive the vehicle, the shaft output of the engine 4 is constant. The relational expression is as follows.

FIG. 2 shows the relationship between the load of the generator and the load for driving the vehicle = engine shaft output = constant.

In this embodiment, if the magnitude of the required load of the vehicle is up to 50% of the maximum possible output value: Fmax, the motor 2
Only the vehicle is driven. The engine 4 is driven so that the energy density of the battery 3 is reduced to 90% or less of the maximum, and the generator 5 is set to a 100% load. The magnitude of the required vehicle load is the maximum possible output value: 50% of Fmax
, The load is gradually distributed to the vehicle drive load. 100%
, The shaft output of the engine 4 becomes 90
% And the load on the generator 5 distributes the remaining 10%.

As described above, the engine 4 is cooled by the electric fan 6. A temperature detector is attached to control the temperature of the engine 4. When the temperature is higher than a certain temperature, the electric fan 6 rotates, and when the temperature is lower than a certain temperature, the electric fan 6 is stopped. Reduce the time that the engine 4 operates in a low temperature state,
By reducing the starting time of the catalyst 7, harmful exhaust gas is prevented from being emitted.

[0024]

As described above, according to the hybrid electric vehicle according to the present invention, the load driven by the shaft of the engine can drive the generator and the vehicle. Emission countermeasures can be easily made by keeping the load constant, and an inexpensive and lightweight engine can be obtained because a throttle valve, a throttle sensor, and an intake sensor are not used. Furthermore, this is an effective means for saving energy by driving at a point where the fuel consumption rate is low.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a hybrid electric vehicle according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram illustrating a relationship between an engine load distribution value and a vehicle required load.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Electric motor, 3 ... Battery, 4 ... Reciprocating engine, 5 ... Generator, 6 ... Electric fan, 7 ... Catalyst, 8
... silencer, 9 ... fuel tank, 10 ... converter, 11 ...
Inverter, 12 radiator, 13 continuously variable transmission, 1
4 circulating pump, 15 vehicle drive wheels, 16 gears, 17
…clutch.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 41/04 310 F02D 41/04 310G F02N 11/04 F02N 11/04 D

Claims (3)

[Claims] 1. An inverter for converting the energy of a battery into electric power, a motor for converting kinetic energy with an electric output of the inverter, the motor being capable of rotating driving wheels of a vehicle, a reciprocating engine and a generator. An output shaft of the reciprocating engine and the generator are connected, and a converter for converting the power from the generator into power is provided.The electric output of the converter charges the battery, and the shaft output of the reciprocating engine is A load can be distributed to a vehicle-driven transmission and a generator, wherein the transmission is connected to the drive wheels to drive a vehicle. In a hybrid electric vehicle, a shaft rotation speed of a reciprocating engine is fixed by the generator. The hybrid electric vehicle is controlled by using the converter. 2. A hybrid electric vehicle according to claim 1, wherein the reciprocating engine has a fixed throttle opening. 3. The hybrid according to claim 1, further comprising a catalyst for purifying exhaust gas from the reciprocating engine, wherein the reciprocating engine is not started until the temperature of the catalyst reaches a certain temperature or higher. Electric car.