JPH11268620A - Energy recovery system for vehicles using gaseous fuel - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the space required for an energy regeneration device. An internal space of a fuel tank is hermetically separated by a movable piston into a fuel chamber filled with CNG and an oil chamber filled with oil. When the vehicle decelerates, the oil device 24 acts as a pump to supply oil into the oil chamber 15 and compress CNG in the fuel chamber 14 to store energy in the form of pressure. CNG in the fuel chamber 14 during engine high load operation or acceleration operation
To cause oil to flow out of the oil chamber 15 and cause the oil device 24 to act as a motor to release the stored energy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle energy regenerating apparatus using gaseous fuel.

[0002]

2. Description of the Related Art Conventionally, an energy regenerating apparatus for a vehicle having an accumulator has been known. In this energy regenerating device, for example, when a vehicle is decelerated, oil is flowed into an oil chamber of an accumulator by a pump connected to an axle and compressed to accumulate energy, thereby storing energy in the form of pressure. The stored energy is released by causing the oil to flow out of the oil chamber by expanding the oil. The oil that has flowed out of the oil chamber drives, for example, a motor.

[0003]

However, since the space of the vehicle is limited, it is difficult to secure a space for mounting the accumulator, and even if the accumulator is mounted on the vehicle, a large amount of energy is required. There is a problem that cannot be stored.

[0004]

According to the present invention, there is provided a gas fuel tank filled with a gaseous fuel and a working fluid filled with a working fluid. Separated sealingly from the fluid chamber, the separation wall is displaceable in accordance with the pressure in the gas fuel chamber and the working fluid chamber, and the working fluid is supplied into the working fluid chamber to compress the gas fuel in the gas fuel chamber. Energy is stored in the form of pressure and pressure, and when the gaseous fuel in the gaseous fuel chamber expands and the working fluid flows out of the working fluid chamber, the stored energy is released. That is, since the gaseous fuel in the gaseous fuel tank is used as the pressure accumulating medium, a separate space for the pressure accumulating medium is not required, and thus the space required for the energy regenerating device is reduced.

[0005]

Referring to FIG. 1, a gaseous fuel engine main body 1 has, for example, four cylinders 1a. Each cylinder 1a
Are connected to a common surge tank 3 via a corresponding intake branch pipe 2, and the surge tank 3 is connected to an air cleaner 5 via an intake duct 4. A fuel injection valve 6 for injecting compressed natural gas (CNG) is arranged in each intake branch pipe 2, and a throttle valve 7 is arranged in the intake duct 4. Each fuel injection valve 6 is controlled based on an output signal from the electronic control unit 30.

Still referring to FIG. 1, reference numeral 8 denotes a torque converter, 9 denotes a propeller shaft, 10 denotes an accelerator shaft, and 11 denotes wheels 11. In the internal space of the fuel tank 12, a movable piston 13 displaceable in the internal space is arranged. A fuel chamber 14 filled with fuel (CNG) is formed on one side of the movable piston 13, and an oil chamber 15 filled with oil is formed on the other side of the movable piston 13. The movable piston 13 is the fuel chamber 1
4 and the oil chamber 15 are hermetically separated, and the fuel chamber 14
The inner space of the fuel tank 12 can be displaced in the axial direction according to the fuel pressure in the fuel tank and the oil pressure in the oil chamber 15.

[0007] A fuel passage 16 communicates with the fuel chamber 14. A shutoff valve 17 and a pressure reducing valve 18 are sequentially arranged in the fuel passage 16, and the fuel passage 16 is connected to each fuel injection valve 6. Therefore, the fuel chamber 14 performs the same function as a conventional fuel tank. The shutoff valve 17 is closed, for example, when the engine is stopped other than when CNG is charged and when an abnormality occurs in the fuel system, and is opened otherwise. The pressure reducing valve 18 is for maintaining the pressure of CNG supplied to each fuel injection valve 6 constant irrespective of the pressure in the fuel chamber 14. A charging passage 19 extends from the fuel passage 16 between the shut-off valve 17 and the fuel chamber 14. In this filling passage 19, a check valve 20 and a filling valve 21 are arranged. The check valve 20 allows CNG to flow only from the filling valve 21 to the fuel chamber 14. The filling valve 21 is normally closed, and is opened when the fuel chamber 14 is to be filled with CNG.

On the other hand, a high-pressure oil passage 22 communicates with the oil chamber 15. An oil control valve 23 which is normally closed is disposed in the high-pressure oil passage 22, and the high-pressure oil passage 22 is connected to a discharge / supply port 24 a of an oil device 24. On the other hand, the suction / outlet 24b of the oil device 24
Is connected to an oil reservoir 26 via a low-pressure oil passage 25. Further, a power transmission control device 27 which is normally turned off is provided between the input / output shaft 24c of the oil device 24 and the propeller shaft 9. When the power transmission control device 27 is turned on in the forward direction, the input / output shaft 24c and the propeller shaft 9 are connected to each other, and at this time, the input / output shaft 24c of the oil device 24 is rotated in the forward direction. When the device 27 is turned on in the reverse direction, the input / output shaft 24c and the propeller shaft 9 are connected to each other, and at this time, the input / output shaft 24c of the oil device 24 is rotated in the reverse direction, and the power transmission control device 27 is turned on. When turned off, the input / output shaft 24c and the propeller shaft 9 are separated from each other.

[0009] The oil device 24 through the discharge / supply port 24a
Is supplied with high-pressure oil, the input / output shaft 24c of the oil device 24 is rotated, for example, in the forward direction. That is, in this case, the oil device 24 functions as a motor. The oil supplied to the oil device 24 is then sucked /
It flows out from the outlet 24b. On the other hand, when the input / output shaft 24c of the oil device 24 is forcibly rotated, for example, in the opposite direction, the oil device 24 sucks oil through the suction / outflow port 24b, and then discharges this oil from the discharge / supply port 24a. . That is, in this case, the oil device 24 functions as a pump. The shutoff valve 17, the oil control valve 2
3, and the power transmission control device 27 is an electronic control unit 3
It is controlled based on the output signal from 0.

The electronic control unit 30 is composed of a digital computer, and is connected to a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, a CPU (Microprocessor) 34, and always connected via a bidirectional bus 31. It has a B-RAM (backup RAM) 35, an input port 36, and an output port 37 connected to a power supply. Surge tank 3 has pressure sensor 3
8 is attached. The pressure sensor 38 generates an output voltage proportional to the absolute pressure in the surge tank 3 representing the intake air amount Q. The opening sensor 38a attached to the throttle valve 7 generates an output voltage proportional to the throttle opening. The output voltages of these sensors 38 and 38a are input to the input port 36 via the AD converter 39. The input port 36 is connected to an idle switch 40 that generates a signal indicating that an accelerator pedal (not shown) is at an idle position, and a vehicle speed sensor 41 that generates an output pulse indicating the vehicle speed V. On the other hand, the output port 37 is connected to the fuel injection valve 6, the shutoff valve 17, the oil control valve 23, and the power transmission control device 27 via the corresponding drive circuits 42, respectively.
Connected to each other.

In the vehicle shown in FIG. 1, for example, energy is stored in the form of pressure during a vehicle deceleration operation, and the stored energy is released in the form of a driving force during an engine high load operation or an acceleration operation. When energy is to be stored, power transmission control device 27 is turned on in the reverse direction, and oil control valve 23 is opened. When the power transmission control device 27 is turned on in the reverse direction, the driving force of the propeller shaft 9 causes the input / output shaft 24c of the oil device 24 to rotate in the reverse direction, and thus the oil device 24 acts as a pump. The oil discharged from the oil device 24 is then supplied into the oil chamber 15. As a result, the movable piston 13 is displaced toward the fuel chamber 14 and CNG in the fuel chamber 14 is compressed, so that energy is stored in the form of pressure. Since the pressure reducing valve 18 is provided, the fuel chamber 14
Even if the CNG inside is compressed, the fuel injection pressure is kept constant.

On the other hand, when energy is to be released, the power transmission control device 27 is turned on in the forward direction, and the oil control valve 23 is opened. As a result, C in the fuel chamber 14
The NG expands and the movable piston 13 is displaced toward the oil chamber 15, whereby the oil in the oil chamber 15 is supplied to the oil device 24 in a high pressure state. As a result, the input / output shaft 24c of the oil device 24 is rotated in the forward direction, and thus the oil device 24 operates as a motor.
The driving force generated by the oil device 24 is transmitted to the power transmission control device 2
The power is transmitted to the propeller shaft 9 via the control shaft 7.

As described above, in the embodiment according to the present invention, the stored energy is released in the form of the driving force during the engine high load operation or the acceleration operation. Therefore, shortage of the driving force of the vehicle can be prevented. For this reason, even if the output of the engine 1 is not extremely large, the driving force of the vehicle can be secured, and therefore, the engine fuel consumption rate can be reduced.

In the embodiment according to the present invention, the fuel chamber 1
4 is used as a pressure storage medium. Therefore, the space required for the energy recovery device can be reduced because a separate space for the pressure accumulating medium is not required, or a large amount of energy can be stored. Further, since a container for the pressure accumulating medium is not required, an increase in weight can be reduced.

Next, an embodiment according to the present invention will be described in more detail with reference to FIG. FIG. 2 shows an interruption routine executed by interruption every predetermined time. Referring to FIG. 2, first, at step 50, it is determined whether the intake air amount Q representing the engine load is larger than a predetermined set amount Q1, or the throttle opening TA representing the vehicle acceleration is set at a predetermined value. It is determined whether or not it is larger than the opening degree TA1. Q> Q1 or TA>
At the time of TA1, that is, at the time of the engine high load operation or the acceleration operation, the routine proceeds to step 51, where the power transmission control device 2
7 is turned on in the forward direction. In the following step 52,
The oil control valve 23 is opened. In this way, energy is released during engine high load operation or acceleration operation.

On the other hand, when Q ≦ Q1 or TA ≦ TA1 in step 50, the process proceeds to step 53, where
It is determined whether or not the idle switch 40 is on. When the idle switch 40 is on, that is, when the vehicle is decelerating, the routine proceeds to step 54, where it is determined whether or not the vehicle speed V is higher than a predetermined set vehicle speed V1. If V> V1, then the routine proceeds to step 55, where the power transmission control device 27 is turned on in the reverse direction. In the following step 55, the oil control valve 23 is opened. In this way, energy is stored during vehicle deceleration.

That is, energy is stored when the idle switch 40 is on and V> V1. When V ≦ V1, the rotation speed of the propeller shaft 9 is low, and the oil device 24 may not work well as a pump. Therefore, in the embodiment according to the present invention, energy is stored when the idle switch 40 is on and V> V1.

On the other hand, when the idle switch 40 is off in step 53, that is, when the vehicle is not being decelerated,
Alternatively, when V ≦ V1 in step 54, the process proceeds to step 56, where the power transmission control device 27 is turned off. In the following step 57, the oil control valve 23 is closed. In the above embodiment, CNG is used as the gaseous fuel.
Is used. However, natural gas and petroleum gas as primary fuels such as liquefied petroleum gas (LPG), coal conversion gas and petroleum conversion gas as secondary fuel, or hydrogen gas can be used as the gaseous fuel.

[0019]

The space required for the energy regenerating device can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall view of a gas-fueled internal combustion engine.

FIG. 2 is a flowchart illustrating an interrupt routine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Gas fuel engine main body 6 ... Fuel injection valve 9 ... Propeller shaft 12 ... Fuel tank 13 ... Movable piston 14 ... Fuel chamber 15 ... Oil chamber 24 ... Oil device 27 ... Power transmission control device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 21/02 F02M 21/02 Z F16D 61/00 F16D 61/00

Claims (1)

[Claims] An internal space of a gas fuel tank is hermetically separated by a separation wall into a gas fuel chamber filled with a gaseous fuel and a working fluid chamber filled with a working fluid, and the separation wall is a gaseous fuel chamber. When the working fluid is supplied to the working fluid chamber and the gaseous fuel in the gaseous fuel chamber is compressed, energy is stored in the form of pressure and the gaseous fuel in the gaseous fuel chamber is displaced. An energy regenerating apparatus for a vehicle using a gaseous fuel in which the stored energy is released when the working fluid flows out of the working fluid chamber due to expansion of the working fluid.