JP2002218601A - Regenerative brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regenerative brake which is able to efficiently regenerate power. SOLUTION: A type of vehicle which drives rear wheels 2 by an engine 1 is constituted to drive front wheels 4 by installing a drive motor 3 which serves as a generator as well, to connect battery 6 with the drive motor 3 through a power control unit 5, and to supply power to the driving motor 3 making the power control unit 5 detect a heavy load to of the engine 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a braking regenerative device.

[0002]

2. Description of the Related Art In recent years, there has been an urgent need to develop a power source that can replace a conventional internal combustion engine due to demands for energy saving and environmental protection.
Under such circumstances, a so-called hybrid vehicle using both an internal combustion engine and a motor has attracted attention in terms of practicality.

In order to further improve efficiency, a regenerative energy system that collects braking force and converts it into running energy has been put to practical use. In this method, the braking force is absorbed as motor power, and this power is charged into a battery to be used as an energy source for re-acceleration.

Further, as shown in FIG. 4, there is an apparatus in which kinetic energy is recovered as pressure. This is F
The present invention is applied to an F (front engine front drive) type vehicle, in which a drive device using a pressure motor is provided on the rear wheel side.

That is, the front wheels 80 are connected to an engine 81, while the rear wheels 82 are connected to a hydraulic pump motor 83. The hydraulic pump motor 83 is connected to an accumulator 85 via an electromagnetic switching valve 84. For the rear wheels, the hydraulic oil accumulated in the accumulator 85 is supplied to the hydraulic pump motor 83, and the rear wheels 82 are driven.

[0006] Thus, the energy accumulated during braking can be used at the time of starting, and the energy can be effectively used.

[0007]

However, as shown in FIG.
In the device shown in (1), the vehicle always travels in the FF, and energy recovery and drive assist are performed on the rear wheel side, and thus have the following problems.

That is, it is known that when braking an automobile, 60% to 80% of the braking force is borne by the front wheels, and the rest is borne by the rear wheels. In the conventional method, braking regeneration is performed on the rear wheel side. Therefore, when the coefficient of friction with the road surface is extremely low, such as in a mirror burn state, the rear wheel slips or almost regenerates. It is only possible to apply a low load (braking force) to the wheels that is not performed.

The present invention has been made in view of the above circumstances, and has as its technical object to provide a braking regenerative device capable of effectively regenerating braking force.

[0010]

SUMMARY OF THE INVENTION The present invention is a braking regenerative device, and is configured as follows to solve the above-mentioned technical problem.

That is, in a vehicle in which the rear wheel 2 is driven by the engine 1, a drive motor 3 for power generation is provided to drive the front wheels 4, and the power control unit 5
The power control unit 5 is configured to detect a high load state of the engine 1 and supply power to the drive motor 3.

As the battery 6, a secondary battery such as lithium, nickel hydride, nickel cadmium or the like is suitable. Also,
Since such a secondary battery is charged and discharged by a chemical change, it is not suitable for rapid large-current charging and deep discharging. Therefore, an electric double layer capacitor may be used as an auxiliary charging place.

The electric double-layer capacitor has a structure in which two current collectors are provided facing each other, an activated carbon electrode layer is formed on each of the opposing surfaces, and each activated carbon electrode layer is filled with an electrolytic solution. .

When a power source (a generator for generating regenerative energy) is connected to the two current collectors, the activated carbon electrodes are charged to the polarity of the power source. Then, the electrons in the electrolytic solution gather on the positive electrode side and become charged. Although this electric double layer capacitor functions as a battery, it can be charged and discharged at high speed because the storage does not involve a chemical change, and has a durability of several hundred thousand times or more.

Further, since a large charge and discharge (deep cycle) with a large current are possible, the efficiency is extremely high. In addition, the main material is harmless carbon and does not use harmful lead or cadmium, so it has little effect on the environment. Further, since the terminal voltage accurately reflects the remaining capacity, it is easy to grasp the remaining battery level. The operating temperature range is wide from -20 to 70 degrees. There is a feature.

At present, the battery has a volume energy density of 6.5 Wh / L and a mass energy density of 4.3 wh / L.
kg, but it is improving every day. In addition, electricity 2
There are two types of multilayer capacitors, an aqueous solution type and an organic solution type, depending on the difference in the electrolytic solution.

The aqueous solution system (1) has high ion mobility and is suitable for large current charging and discharging, (2) is stable in the atmosphere,
(3) It is nonflammable, and (4) its manufacturing cost is low.

On the other hand, the organic solution system has (1) a high withstand voltage,
(2) Small size and high energy density can be obtained. (3) Metal can be used for the cell. (4) Wide operating temperature range. (5) High resistivity.

Considering these characteristics as a regenerative energy recovery battery, the regenerative energy that rises sharply
There is an advantage that it can be recovered as 00% electric energy.

As described above, if this power is discharged first, frequent charging and discharging of a battery (main battery) such as lithium or nickel cadmium is reduced, and the life of the battery is extended.

Here, when the load of the engine 1 is large, specifically, when starting, accelerating, climbing a hill, etc., the assist of acceleration is mainly performed at the time of starting by using up the electric power of the electric double layer capacitor. . Thereafter, the power supply is switched to the power supply from the battery 6 and the power supply to the traveling motor is continued.

The charging of the battery 6 is performed during steady running and during regenerative braking. The maximum current generated during regenerative braking depends on the friction coefficient between the wheels and the road surface. Not only is it impossible, but there is even danger. In the present invention, since the brake regeneration is performed on the front wheels at which the slip limit with respect to the road surface is greatly improved during braking, there is almost no possibility of slipping, and extremely efficient regeneration (power generation) becomes possible.

As a second configuration, in a vehicle of the type in which the engine 1 drives the rear wheels 2, a driving motor 3 for power generation is provided to drive the front wheels 4.
A battery control unit 5 is connected to a battery 6 via a power control unit 5, a rotation speed sensor 7 for detecting a rotation speed of each wheel and outputting a signal to the power control unit 5 is provided, and a brake control unit for controlling a brake 8 of each wheel. The power control unit 5 detects the high load state of the engine 1 and the slip of the rear wheel 2 and supplies power to the drive motor 3, and the brake control unit 9
To suppress wheel slip.

With such a configuration, when the drive wheels slip as in the case of starting on an ice burn, the front wheels also immediately exert the driving force, and the running performance as a four-wheel drive vehicle is obtained.

[0025] For this reason, superior lightness and excellent fuel economy can be obtained as compared with a full-time four-wheel drive vehicle (a constant four-wheel drive vehicle in which the front and rear wheels are connected by a viscous coupling or the like). Further, since the driving assist is performed by electric power, a long-term driving force can be obtained, and a driving performance closer to that of an actual four-wheel drive vehicle can be obtained as compared with the case using pressure. That is, not only at the time of starting, but also an unstable element such as a crosswind on a highway can be handled as four-wheel drive.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a braking regenerative device according to the present invention will be described in more detail with reference to the embodiments shown in FIGS.

FIG. 1 shows a block diagram. An engine 1 is installed at a rear part of a vehicle body and drives a rear wheel 2 via a transmission (torque converter). The rear wheel 2 is provided with a brake 8 and a rotation speed sensor 7 for measuring the rotation speed of the wheel.

On the other hand, the front wheels 4 of the vehicle are connected to a drive motor 3 for power generation via a differential gear 10 and an electromagnetic clutch 3a. The drive motor 3 has a power control unit 5
The battery 6 and the electric double-layer capacitor 6a are connected via the.

The front wheels 4, 4 are also provided with a rotation speed sensor 7 and a brake 8. The power control unit 5 is controlled by a microprocessor 5a to optimize charging and discharging. The microprocessor 5a includes an I / O 5b
The calculation is performed on the basis of various information input from the computer.

The I / O 5b receives brake strength, accelerator opening, suction negative pressure, battery voltage, electric double layer capacitor voltage, shift information (gear position information), and the like.

A rotation speed sensor 7 provided for each wheel is for anti-lock brake control. When a wheel is locked or is about to be locked due to a decrease in road surface friction coefficient or the like, the rotation force sensor 7 detects the braking force of the wheel. Release the grip to recover it. A brake control unit 9 is provided to perform such antilock brake control.

The basic operation of the power control section 5 is to detect the high load state of the engine 1 and the slip of the rear wheels 2 to supply power to the drive motor 3, which will be described with reference to FIG. Then, when the vehicle speed is A1 and the vehicle is in an acceleration state, the microprocessor 5a detects this from the accelerator opening and the like, and supplies electric power to the drive motor 3 to assist in acceleration (C1). Then, in a steady state (constant speed running state, A2), the assist is stopped.

Then, at the same time when the brake is depressed and the vehicle speed drops (A3), the drive motor 3 acts (regenerates) as a generator to charge the battery 6 (C2). Here, when the stopped vehicle is brought into the rapid acceleration state (A4), the rear wheels 2 slip. Then, a difference in rotation speed between the front wheel and the rear wheel occurs (B1), so that the microprocessor 5a determines from the information from the rotation speed sensor 7 that a strong assist is necessary, and drives a current (C3) larger than the normal acceleration. Supply to motor 3.

Subsequently, when deceleration (A5) is performed, the drive motor 3 acts as a generator to charge the battery 6 (or the electric double layer capacitor 6a) (C4). At this time, if the braking force exceeds the friction between the wheel and the road surface, a slip occurs, so that the above-described antilock brake control is performed.

This will be described with reference to the flowchart shown in FIG. 3. In step 100, it is determined whether or not the vehicle is in a start state. Only the positive branch proceeds to the next step 101, and the drive motor is driven with an output corresponding to the accelerator opening. 3 is activated.

Here, when the brake is applied (step 10)
2), the positive branch proceeds to step 103, where the drive motor 3 acts as a generator to recover energy. On the other hand, the negative branch of step 102 shifts to step 104 where it is determined whether or not the rear wheel 2 is idling. In the positive branch of step 104, a large current is supplied to the drive motor 3 to perform assist. If the rear wheel 2 is not idling (negative branch of step 104), steady driving is performed in step 105.

The electromagnetic clutch 3a connects the drive motor 3 to the drive system only when the drive motor 3 is in a drive or regenerative state. If the drive motor 3 is constantly connected, it is disadvantageous in terms of noise and the like, but the drive motor 3 does not necessarily have to have a structure that can cut off the power.

Since the electric double-layer capacitor 6a is suitable for charging and discharging with a large capacity in a short time, all the regenerative energy is charged in the electric double-layer capacitor 6a, and this electric power is preferentially used when the vehicle starts. By using the battery, wasteful charging and discharging of the battery 6 is eliminated, and the efficiency can be further improved.

The anti-lock brake control is not necessarily required to be independent for four wheels (four channels).
A total of three channels, one channel and one rear wheel, may be used. In addition, since the driving of the front wheels 4 is performed by the drive motor 3, anti-slip control during acceleration is also easy. That is, when the front wheels 4 slip, the slip state can be eliminated only by controlling the power supply to the drive motor 3.

Further, in a general full-time four-wheel drive vehicle, one of the front and rear wheels, for example, a rear wheel is directly connected to an engine, and the other front wheels are connected via a slip permitting device such as a viscous coupling. This indicates that the rotational torque of the front wheels does not exceed that of the rear wheels, which has various effects on the maneuverability.

In the present invention, since the front wheels are driven electrically, the torque split is optional, and a wide range of settings is possible from the viewpoint of maneuverability. In addition, since the drive sources are completely independent of the front and rear wheels, even if an engine trouble occurs at an intersection or a railroad crossing, the vehicle can be electrically driven to a safe place by itself and is excellent in safety.

[0042]

According to the present invention, a drive motor for power generation is provided to drive the front wheels, and a battery is connected to the drive motor via a power control unit. Since it is configured to detect and supply power to the drive motor, the vehicle normally travels with rear wheel drive, and can assist the front wheels only when starting or when the engine load is high.

Since the energy can be regenerated on the front wheel side, the power that can be generated can be set high, and the braking force can be effectively regenerated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a braking regenerative device according to an embodiment of the present invention.

FIG. 2 is a timing chart showing an operation principle of the braking regenerative device according to one embodiment of the present invention.

FIG. 3 is a flowchart illustrating the operation principle of the braking regenerative device according to one embodiment of the present invention.

FIG. 4 is a configuration diagram of a vehicle showing a conventional braking regenerative device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine 2 rear wheel 3 drive motor 4 front wheel 5 power control unit 6 battery 7 speed sensor 8 brake 9 brake control unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60T 8/00 B60K 9/00 E

Claims (2)

[Claims] 1. A vehicle in which a rear wheel is driven by an engine, a driving motor for power generation is provided to drive front wheels, and a battery is connected to the driving motor via a power control unit. A braking regenerative device configured to detect a high load state of an engine and supply electric power to a drive motor. 2. A vehicle of a type in which rear wheels are driven by an engine, a driving motor for power generation is provided to drive front wheels, and a battery is connected to the driving motor via a power control unit, and the rotation speed of each wheel is controlled. Provide a rotation speed sensor that outputs a signal to the power control unit and detects a brake control unit that controls the brake of each wheel, the power control unit detects a high load state of the engine and slip of the rear wheel. While supplying power to the drive motor,
A braking regenerative device characterized by being configured to control a brake control unit to suppress wheel slippage.