JPS58220960A - Pressurized air system fuel injector - Google Patents

Abstract

PURPOSE:To prevent defective operation of a change-over mechanism due to heat thereof and improve the injection property and combustion property of fuel by providing a check valve having high heat resisting property and pressure resisting property in the change-over mechanism for a pressurized air supply source. CONSTITUTION:While a fuel injector Z1 supplies pressurized air from an air tank 3 to a fuel injection valve 2 in the start of an engine having low discharge pressure of a compressor 1, it shuts off air from the tank 3 to supply pressurized air from the compressor 1 when the discharge pressure reaches at least a set value. A check valve 15 having high heat and pressure resisting properties is arranged at the very hot air path 21 side of this change-over mechanism so that a solenoid change-over valve 6 and a constant differential pressure valve 7 in an air path 22 connected from the air tank 3 to the downstream air side of the check valve 15 are not exposed directly to hot air from the compressor 1, the solenoid change-over valve 6 does not have any defective operations due to temperature rise and the change-over operation of an air supply source has no troubles.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressurized pneumatic fuel injection device using a pneumatic fuel injection valve.

This type of fuel injection device directs pressurized air from a compressor driven by an engine to a fuel injection valve, and uses this pressurized air to atomize fuel and inject it into a cylinder. When the engine starts, the discharge pressure of the compressor is low and the amount of air is small, so in this case, pressurized air set to a predetermined pressure is temporarily supplied to the fuel injection valve from a separate air tank, etc. There is a need to.

In conventional fuel injection systems, an air source switching device is installed in the air supply path in order to switch the air supply source according to the operating state of the engine. An electromagnetic switching valve that opens and closes depending on the timing is provided, and the compressor and the air tank are selectively connected to the fuel injection valve by the electromagnetic switching valve.

However, in a conventional fuel injection device having a switching device using an electromagnetic switching valve as described above, the electromagnetic switching valve directly operates /001. ! Because it is exposed to air discharged from the compressor at a high pressure and high temperature of ~4100°C, the magnetic attraction force of the solenoid coil of the electromagnetic switching valve gradually decreases as the temperature rises, causing the electromagnetic switching valve to malfunction. There was a problem that the injection characteristics and combustion characteristics of the fuel deteriorated.

In view of the problems of the conventional pressurized air fuel injection device as described above, the present invention aims to improve the injection characteristics and combustion characteristics of fuel by preventing malfunction of the switching device due to heat. The purpose of this invention is to provide a pressurized air fuel injection device which is driven by an engine and a pneumatic fuel injection valve designed to atomize and inject fuel using pressurized air. The compressor is connected to the compressor via a first air passage having a check valve interposed therebetween that acts like a heather to prevent backflow of air from the fuel injection valve side to the compressor side; An air tank is connected to a position downstream of the check valve in the air passage via a second air passage, and an air tank is connected to the second air passage depending on the operating state of the engine. A control valve for controlling the opening and closing of the air passage as appropriate; A constant differential pressure valve is interposed that operates to set the air pressure from the air tank supplied to the first air path side through the air path to a pressure higher than the discharge pressure of the compressor by a certain pressure. It is something to do.

/Embodiment A fuel injection device Z according to the embodiment is shown.

This fuel injection device is a pneumatic fuel injection valve installed in a gas turbine engine, and the pressurized air in a compressor driven by the engine and the air tank 3 installed separately from the engine are pressurized. Air is controlled by engine operating conditions (
The supplied pressurized air mixes the fuel pumped from the fuel pump J side through the fuel pipe No. 0 with air and supplies it to each cylinder. The first air path connects the compressor 1 and the fuel injection valve, and the second air path from the air tank 3 is in the middle of 2/2. is connected.

A switching device RX is attached to the first air paths m, 2i and the second air path Ω.

Switching equipment RX i, i, the fuel injection valve is located at the air upstream position from the confluence of the first air path, 2/ and the second air path!
A first check valve /j acts to prevent backflow of air from the side to the compressor/side, and a first air path λ! an electromagnetic switching switch A disposed in the compressor and acting to self-close the second air passage 2.2 in response to the discharge pressure of the compressor;
In 2, the electromagnetic switching non-A side air pressure is arranged on the downstream side of the air tank 3 side to the fuel injection valve! It is comprised of a constant differential pressure valve 7 which is used to set the pressure of air supplied to the side at a constant pressure higher than the discharge pressure of the compressor.

Further, the electromagnetic switching non-A control circuit YK includes a main switch 10 that operates in conjunction with an engine starting switch (not shown), and a j-th
There is interposed a pressure valve which opens and closes depending on the discharge pressure of the compressor which is loaded via air M, lt.

The pressure switch ll/ is configured to open the electromagnetic switching valve A when the discharge pressure of the compressor/ falls below a predetermined set pressure.

In addition, the code /O is the first air path, 2/ and the first air path, 2.2
A check valve provided in the bypass passage 23 that bypasses the
A is an air passage for setting the outflow pressure of the constant differential pressure valve 7.

On the other hand, the air tank 3 has a charging path, 2I1. The charging compressor is connected via the. This charging compressor≠
is operated when the air pressure in the air tank 3 detected by the pressure switch /2 installed in the control circuit Q drops below the set pressure (compressor discharge pressure, a pressure slightly lower than btt). , acts to maintain the air pressure in the air tank 3 at a set value. In addition, the code|symbol /7 is a check valve which prevents the pressurized air in the air tank 3 from flowing back to the charging compressor j side.

Next, the operation of the fuel injection system @Z of the first embodiment configured as described above will be explained. When the engine is rotated by an appropriate starter device (not shown) K (main switch 10 is turned on), The compressor starts rotating and pumping air, but in this case, the engine speed is low, so the discharge pressure and discharge amount are low.

For this reason, the pressure valve 1/1 is kept in the ON state, and the electromagnetic switching valve A is opened and the pressurized air stored in the air tank 3 passes through the second air path 2.2. Fuel injection valve! Supplied on the side. In this case, the constant differential pressure valve 7 is set so that the air pressure flowing out from the constant differential pressure valve 7 is higher than the discharge pressure of the compressor by a constant pressure, so the first check valve /j is in the closed state. If the fuel injection valve λ is maintained as it is and pressurized air is supplied only from the air tank 3, the value becomes K. Furthermore, if the pressure inside the air tank 3 drops below the set value due to the air supply to the fuel injection valve 2,
The pressure switch 2 is turned on and the air tank 3 is filled with air by the filling compressor. Incidentally, when the air pressure in the air tank 3 reaches a set value (that is, when filling is completed), the pressure switch 2 is turned on and the operation of the filling compressor is stopped.

When the engine starts and the discharge pressure of the compressor reaches the set pressure, the pressure switch I-/ turns OFF, the electromagnetic switch A closes, and the air supply from the air tank 3 is cut off. Pressurized air, in turn from the compressor/, is supplied to the fuel injection valve via the first check valve/j. That is, the air supply source is switched from the air tank 3 to the compressor.

On the other hand, after the engine has transitioned to steady operation, the main switch /θ is turned OFF, so the electromagnetic switching switch A remains closed regardless of the discharge pressure of the compressor. of pressurized air is continuously supplied to the fuel injection valve J. In addition, in the case of Jin, the air tank 3 has an 8L2 check valve/
It is charged with discharge air of the compressor/compressor which enters from bypass line 23 via 6. In this way, if the air tank 3 is filled with air discharged from the compressor after the engine is started, the fuel injection valve λ will be activated when the engine is restarted.
The air tank 3 also quickly supplies pressurized air at a pressure corresponding to the discharge pressure of the compressor, thereby making it possible to start the engine easily and quickly.

In addition, in the case of the illustrated embodiment, a check valve /j with excellent heat resistance and pressure resistance is provided on the first air path 27 side, which becomes extremely high temperature.
Since the electromagnetic switching valve and the constant differential pressure valve 7 are provided in the second air passage 2.2 from the air tank 3 connected to the air downstream side of this check valve /j, the electromagnetic switching valve is not A. The fixed differential pressure valve 7 is not directly exposed to high-temperature air from the compressor, and unlike conventional fuel injection systems, the electromagnetic switching valve malfunctions due to temperature rise, which interferes with the switching operation of the air supply source. It is possible to prevent such troubles from occurring before they occur.

As mentioned above, the fuel injection device Z of this first embodiment.

However, when starting the engine when the discharge pressure of the compressor is low, pressurized air is supplied from the Kii air tank 3 to the fuel injection valve.
When the engine starts and the discharge pressure of the compressor reaches the set pressure or higher, the air supply from the air tank 3 is cut off and pressurized air is supplied from the compressor to the fuel injection valve λ. There is. In addition, in this embodiment, 1. switching of the air supply source is controlled by the discharge pressure of the compressor; Example fuel injection device Z
To explain, the fuel injection device 2 of this second embodiment. This has almost the same basic configuration as the fuel injection device Fjt, Z of the seventh embodiment, but differs from the first embodiment only in the control method of the electromagnetic switching valve 2. That is, the first
In fact, in the upstream fuel injection system flZ, the electromagnetic switching non-A
is controlled by the discharge pressure of the compressor, but in the case of the Z-pipe of the fuel injection device of this second embodiment, the discharge pressure of the compressor is approximately proportional to the engine speed. Focusing on the control circuit Y of the electromagnetic switching non-A, an electromagnetic switching device 2 whose opening and closing are controlled by an electrical signal transmitted from a rotation speed sensor 37 that detects the engine rotation speed is used.
is provided to control the opening and closing of the electromagnetic switching valve t according to the engine speed. In this case, when the engine speed reaches, for example, 40 to 70% of the rated speed, the electromagnetic switching valve t is closed to switch the air supply source from the air tank 3 side to the compressor/side. . .

When the electromagnetic switching valve A is controlled to open and close according to the engine speed as in the second embodiment, the air piping for controlling the electromagnetic switching valve (reference numeral in FIG. 1) is used as in the seventh embodiment. , 2j) is no longer necessary, and the simplification of the device can be promoted accordingly.

The fuel injection device 2 according to the third embodiment of the present invention shown in FIG.
In the fuel injection device 2 of the first embodiment, the opening/closing control of the electromagnetic switching non-A is performed by a delay switch 3 provided in the control circuit of the electromagnetic switching non-A. The only difference is that all other basic configurations are the same as in the first embodiment. That is, the fuel injection device 2 of this embodiment. After stopping the engine starter (not shown), the delay switch 3 is turned off and the electromagnetic switching valve 6 is closed after a predetermined period of time. Even when the electromagnetic switching valve 6 is controlled by the delay switch 3 in this way, as in the case of the second embodiment, the air piping for controlling the electromagnetic switching valve 6 is not required. The device can be simplified more easily than in the first embodiment.

Moreover, the fuel injection device z6 of the first embodiment of the present invention shown in FIG.
has the same basic configuration as in each of the above embodiments, but
The control method for the electromagnetic switching non-A is different from that of the previous embodiments. That is, this fuel injection device z4 is an electromagnetic switching non-A
In the control circuit Y of the control circuit Y, a pressure switch I1.
The control circuit Y is opened and the electromagnetic switching valve 6 is closed when the discharge pressure of the fuel pump J reaches a fuel pressure at which spray from the fuel injection valve is considered to be sufficiently developed. It has become.

Next, to explain the present invention in detail, the pressurized air fuel injection device of the present invention is one of the switching devices for switching and controlling the pressurized air supply source to the fuel injection valve according to the operating state of the engine. A check valve with excellent heat and pressure resistance is used as a component, and this check valve allows the other components of the switching device, such as the control valve or differential pressure valve, to be directly exposed to the high temperature air from the compressor. In order to prevent the deterioration of the operating characteristics of the fuel injection system, the electromagnetic switching valve that acts as a switching device is installed directly in the air path from the compressor, similar to the conventional fuel injection system. The practical effect is that the operation of the electromagnetic switching valve becomes unstable and garbled due to temperature rise, which interferes with the switching operation of the air supply source, and the fuel injection characteristics and combustion characteristics can be completely improved. be.

Hiroshi Simple Explanation of Drawings Fig. 1 is a basic configuration diagram of a fuel injection device according to a first embodiment of the present invention, Fig. 2 is a basic configuration diagram of a fuel injection device according to a first embodiment, and Fig. 3 is a basic configuration diagram of a fuel injection device according to a first embodiment of the present invention. A basic configuration diagram of a fuel injection device according to a third embodiment of the present invention, and the second figure is a basic configuration diagram of a fuel injection device according to a Vth embodiment.

／　　　・　・・　Compression Machine K...Fuel injection valve 3. Own air tank A...Control valve 7... Constant differential pressure valve /j...Check valve , 2/... First air path 2.2...Second air path 9'31 Figure 2

Claims (1)

[Scope of Claims] / A pneumatic fuel injection valve (2) which atomizes and injects fuel using pressurized air and a compressor (1) driven by an engine are installed in the middle thereof. Fuel injection valve (,2
) 11111 to the compressor (1) side via a seventh air passage (2/) interposed with a check valve (/j) that acts to prevent air from flowing back into the compressor (1) side, and 1 air passage (-2)) said check valve (/j)
Connect the air tank (3) to the downstream side of the air tank via the second air path (2, 2), and then proceed further. The second air passage (, 2-2) is provided with a control valve (1,>) that controls opening and closing of the second proboscis air passage (, 2, 2) as appropriate depending on the operating state of the engine. The air pressure from the air tank (3) supplied to the first air passage (, 2/ ) through the passage (, 2, 2) is made higher than the discharge pressure of the compressor (1) by a constant pressure A pressurized air fuel injection device characterized in that a constant differential pressure valve (7) is interposed and acts as a setting.