JPS6114468A - Fuel injector - Google Patents

Abstract

PURPOSE:To permit the control for minute fuel-amount by jetting-out the fuel which is formed into droplet form by driving an electric-strain vibration element and increasing the dynamic range of the injection amount. CONSTITUTION:Gas-foams are pushed-out from a filter 20 by a solenoid 27, and a piezo element 2, fuel pump 13, and an air pump 16 start operation. Therefore, the air pressure in a pressurized-air chamber 10 is kept at P1, and the fuel pressure in a liquid chamber 6 after the turning-OFF of solenoid 27 is kept at P2. When a starter switch is turned-ON, an output signal is applied into a solenoid 22, and a shutter 18 is witched to an opening position from a closing position. When an engine key is put at ON position, a computer 11 outputs the output in the optimum number of pulses for start into each piezo element 2, and fuel droplets (g) are jetted into a suction passage 4 simultaneously with the opening of an injection port 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device for an internal combustion engine, and more particularly to a fuel injection device for injecting fuel into an intake passage of an internal combustion engine.

The internal combustion engine for a vehicle needs to change its operating state over a wide range from idling to full load operation 1, and the intake air amount and fuel supply amount are adjusted over a wide range. Among these, as one method for adjusting the amount of fuel supplied, a fuel supply system is known in which a fuel injection device is attached to the intake passage of a Kallin engine, and thereby fuel is injected into the intake passage. This fuel supply system pressurizes fuel using a fuel pump, and injects this pressurized fuel at the appropriate time by opening and closing a solenoid valve in the fuel injection device. , and is adjusted according to engine speed, etc.

As described above, the fuel injection device used in the conventional fuel supply system is a solenoid valve as an on-off valve, and the minimum injection amount and maximum injection amount are determined by the response characteristics of the solenoid.

In this case, the maximum injection amount of the fuel injection device is often regulated to be 40 to 80 times the minimum injection amount, resulting in a narrow dynamic range. On the other hand, the dynamic range requested by Ennon often exceeds 100. For this reason, conventionally when matching an engine and a fuel injection device, the minimum injection amount of the fuel injection device was increased to enable full load operation on the engine side, and thereby the maximum injection amount of the fuel injection device was increased. The dynamic range required by the engine is adjusted to the injection equivalent to 1.00. For this reason, the conventional fuel injection device has a problem in that it cannot perform minute fuel amount control during the injection operation of the minimum injection amount. An object of the present invention is to provide a fuel injection device that can eliminate the above-mentioned problems.

In order to achieve the above-mentioned object, the present invention injects fuel in a liquid chamber equipped with an injection port as fuel droplets into an intake passage of an internal combustion engine by driving an electrostrictive vibrator that receives an electric signal.
It is characterized by being equipped with an on-off valve that closes the injection port in a timely manner, and a filter that can be accessed by an air release path extending from the upper position of the liquid chamber and that allows only pressurized gas to pass through.

In such a fuel injection device, an electrostrictive vibrator is driven every time an electric signal is received, and the fuel is turned into fuel droplets and injected.
The maximum injection amount can be increased relative to the minimum injection amount, that is, the dynamic range of the injection amount can be increased. In particular, it is possible to timely close the injection port and increase the fuel pressure on the liquid chamber side to release only the gas in the liquid chamber to the atmosphere through the filter.

FIG. 1 shows a fuel injection device as an embodiment of the present invention. This fuel injection device is attached to an intake pipe 1 of a gasoline engine (not shown), and is formed by arranging a plurality of main bodies 3 each having a piezo element 2 therein as an electrostrictive vibrator. The number of main bodies 3 used is sufficient to ensure the maximum injection amount to the engine, and the arrangement may be in a plane as shown in Figs. 4 and 5, or as shown in Fig. 6. The main bodies 3 may be arranged in multiple rows along the intake passage 4 in the intake pipe 1. In FIG. 1, one of the main bodies 3 will be mainly explained.

The main body 3 has a body 5, a liquid chamber 6 in the body, and a liquid chamber 6.
an injection lower formed on the side opposite to the intake passage 4, a fuel supply chamber 8 communicating with the liquid chamber 6 near the injection lower, and an opening 9 formed in the opposite position to the injection lower. It is formed by an air chamber 10, a valve 18 serving as an on-off valve for opening and closing the injection lower, a gas discharge path 19 extending from the liquid chamber 6, and a filter 20 fitted in the gas discharge path. The entire upper wall of the liquid chamber 6 is formed by the piezo element 2, a small diameter injection lower is provided at the lower end, and the entire liquid chamber 6 has a substantially inverted conical shape. The piezo element 2 has electrodes (not shown) formed on its upper and lower surfaces, to which a driving pulse signal is applied from the combination 1. Here, when the pulse signal of voltage V rises from OFF to ON as shown in FIG. 2(b), the piezo element 2 is distorted as shown by the two-dot chain line in FIG. 2(a). Piezo element 2 converts electrical energy into mechanical energy. This mechanical energy is converted into acoustic energy and transmitted into the fuel G in the liquid chamber 6, and as a result, the fuel is turned into particles and is injected as fuel droplets G from the injection lower (see Fig. 3 (a)). . In addition, the fuel G of the injection lower
1-1: Under the action of surface tension, a liquid film G1 is formed,
This unwinds the injection lower. In this case, it is necessary to maintain the pressure difference between the inside and outside of the injection lower within a certain value, and if it exceeds this value, the liquid film G] will be destroyed. The fuel supply chamber 8 is formed in a direction perpendicular to the long liquid chamber 6 below the road, as shown in FIG.
When the piezo element 2 returns to the non-driving state as shown in cL), fuel can be supplied to the liquid chamber 6. Gas release path]
Reference numeral 9 extends in a substantially horizontal direction from the outermost part of the liquid chamber 6, and when air bubbles are generated in the liquid chamber 6, they are guided to the inner wall surface of the filter 20. The filter 20 is made of a porous layer so small that no capillary phenomenon occurs, and has the property of allowing only gas to pass through and blocking the passage of liquid when the inside of the liquid chamber 6 is pressurized by a predetermined amount. A material formed by laminating a porous membrane and a porous support plate, or a material formed by laminating a special cloth (for example, product name: Goatenox) and a porous support plate are used.

The pressurized air chamber 10 is formed closest to the intake path 4 in the body 5, and is supplied with pressurized air from the air pop 6 side through an air pipe 15. The pressurized air that has flowed into the pressurized air chamber 10 flows out through the opening 9 into the intake path 4 where the intake pressure PO is a negative pressure.
Moreover, air pressure P1 is applied to the injection lower. In addition, the air pressure P
1 only needs to be able to form a liquid film G1 on the injection lower, and the pressure is regulated by a pressure regulating means (not shown) so that it is equal to or close to the fuel pressure P2 in the liquid chamber 6. The shutter 18 is a normally closed solenoid 1 valve, and the solenoid 22H is a 171-inch valve.
The output signal from the combination 1) causes the A movement 1 and the /y/y 18 to be moved from the closed position to the open position (
It is switched and held at the position shown by the solid line in FIG. In addition, 7
The barrel 18 slides into the kite groove 23 formed on the inner wall of the pressurized air chamber 0, and is always held by the spring 24. It is pressed against the side wall of the injection [17], and when in the open position, the injection [17] is opposed to the opening 181.

A 1d fuel pipe 2 is connected to the fuel supply chamber 8, and a check valve 25, a fuel bonzo 1; 3, and a fuel cylinder 14 are connected to this fuel pipe. Moreover, the check valve 25 and the fuel supply chamber 8
The check valve 25 is placed between the fuel pressurizing means and the plunger 26 at (-). It is possible to prevent backflow and, moreover, to flow the fuel, which is regulated to a predetermined fuel pressure P2 by a fuel pressure regulating means (not shown) on the fuel pump 13 side, into the fuel supply chamber 8, and the plunger 26 is a combination unit 1] When the solenoid 27 is kept in the closed position and the solenoid 27 is turned on, the sylanger 26 can pressurize the liquid chamber 6 side. Opening/closing control of gran input 26 and piezo element 2 in main body 3,
jj: i% drive control is performed respectively.

In closing control, the computer 11 does not turn off the output to both solenoids 22 and 27 while the engine/<--21 is off.

When the engine 〜---21 is turned on, immediately after that, 19
The solenoid 27 is turned on and the solenoid 22 is kept off for a pressurizing time T of one fixed amount (see FIG. 7). In addition, Pi'
Output to element 2 also starts. 7y, pressurization time T1
Before the I/RC Stark switch (not shown) turns on, solenoid 21 turns off,
Solenoid 22 remains on.

When the starter switch is turned on after a predetermined amount of time T2 has elapsed since the pressurization key 21 was turned on after the pressurization time T1 has elapsed, the solenoid 22 switches the off switch 18 to the open position.

On the other hand, in the drive control of the piezo element, the combination 11 (Keyaki, airf L+-7/Lee-17 inputs pulse E 1 based on the intake; Each operating condition is detected by human power (rj-j,; by (pull, toe &-j, ac-hill processor, synchronous rotation several tens of times, etc.), and the optimum airflow is determined according to The amount of fuel supplied that provides the fuel ratio is used. Then, in order to obtain one number of pulses corresponding to this amount of fuel supplied, apply a predetermined Ichikawa Vl17) pulse to the piezo element a predetermined number of times in a convex unit time. Output,.

[I] fuel injection device (rJ, engine/fukey-2
1 of 2) (JJ operation (7B1 starts. Is the output signal from the controller 1'l or pressurization 1 interval T) and is output during this 1. Nyori solenoid. 27 or bran/-・
26; 3. As a result, the air bubbles that had accumulated in the VC liquid chamber 6 while the vehicle was stopped are pushed out through the filter 20. At the same time, the piezo element j-2, the combustion engine 13, and the air bomb 16 start driving. As a result, the air pressure in the pressurized air chamber is maintained at 0 or P, and the combustion extinguishing pressure in the liquid chamber 6 is maintained at P2 after the solenoid 27 is closed. When the Stark switch is turned on after the elapsed time T2 of turning on the second generator, an output signal is applied to the solenoid 22, and the first switch 18 is switched from the closed position to the open position.

By the way, when the on/off key is turned off, the combination coater 11 outputs the optimum number of pulses for starting to each piezo element 2, and at the same time as the injection lower is opened, the fuel
is injected into the intake passage 4. In this case, fuel droplets g are injected from each of the plurality of main bodies 3, whereby the air-fuel mixture formed in the intake passage 4 is combusted in a combustion chamber (not shown), and the engine is started. After this, the combi-tar 11 outputs the optimum number of pulse signals to the main body 3 of N(l, do.

Although the fuel supply device shown in FIG. 1 is equipped with a sylanger 26 as a fuel pressurizing means, this plunger 26 may be removed if necessary. In this case, the fuel pump 13
The discharge pressure from the check valve 25 and the fuel supply chamber 8 are directly connected to the check valve 25 and the fuel supply chamber 8 without reducing the discharge pressure by a fuel pressure regulator (not shown).
It may also be added via an path path (not shown) between the two.

Alternatively, a means for stopping the depressurization operation may be installed at the fuel pressure regulator (not shown), and the stopping means may be activated when fuel is pressurized to add high-pressure fuel to the liquid chamber 6 and remove gas. .

In this way, the fuel injection device according to the present invention has the piezo element 2
Because it is driven by a pulse signal, the piezo element can be driven approximately 10,000 to 20,000 times per second, allowing for a sufficiently wide range of fuel injection amount, making it possible to control the injection amount more accurately and more valuable than the minimum. . In particular, even if air bubbles occur in the liquid chamber 6, they can be removed at a timely manner (in the above description, just before startup, or at any other time), and the main body 3 can always inject properly. Can operate.

[Brief explanation of the drawing]

Fig. 1+a is a schematic sectional view of a fuel injection device as an embodiment of the present invention, Figs. 5 is a schematic sectional view of FIG. 4, FIG. 6 is a schematic sectional view of another arrangement of the same main body, and FIG. 7 is a schematic sectional view of FIG. 1. The diagram shows the operation of the fuel injection system and the time chart. 2 piezo element, 4 intake path, 6 liquid chamber, 7
injection port, 9-・opening, 18
Gas discharge path, 2o ・Filter, G Fuel, Gl
liquid film, g fuel droplets. Ryo? Z Ryo 3 figure

Claims (1)

[Claims] a liquid chamber that is disposed opposite to the intake passage of the internal combustion engine and receives fuel supply; an electrostrictive vibrator that transmits vibrations to the fuel in the liquid chamber by receiving an electric signal; It has an injection port that can be sealed with a liquid film, an on-off valve that opens the injection port in a timely manner, and a filter that is attached to a gas discharge path extending from a position above the liquid chamber and that allows only pressurized gas to pass through. A fuel injection device that injects fuel droplets into an intake passage through the injection port.