JPH0826810B2 - Fuel injector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel injection device suitable for use in injecting and supplying fuel to, for example, an automobile engine, and more particularly, to a premixing injection valve and the like. And a fuel injection device for improving idle stability and the like.

[Conventional technology]

The applicant of the present invention has previously filed Japanese Patent Application No. 63-106541 and Japanese Patent Application No.
No. 308669 (hereinafter referred to as "prior art"), a first injection valve for injecting fuel into each cylinder of an engine and a second injection valve for injecting fuel for premixing are provided.
A predetermined premixing ratio ε (0 <ε ≦ from the second injection valve
Based on 1), a fuel injection device was proposed in which fuel is shared and injected.

In this type of fuel injection device, a second injection valve is provided inside the collector of the intake pipe so as to face the ultrasonic transducer, and the premixing fuel injected from the second injection valve is tuned to the harmonic transducer. By atomizing the particles, a uniform premixed gas can be formed to improve the low temperature startability and the idle safety.

[Problems to be Solved by the Invention]

By the way, in the above-mentioned prior art, each injection valve incorporates an electromagnetic actuator, and this electromagnetic actuator is driven by an injection pulse output from the control unit, and the injection amount of fuel is controlled according to the pulse width of this injection pulse. I am trying. However, since the injection valve injects fuel with the characteristic shown by the solid line in FIG. 5, for example,
The pulse width of the injection pulse is reduced, for example, a second scheduled injection amount T _IS due to the injection valve is equal to or less than a predetermined low level T _isL, planned injection in proportion to the pulse width as the characteristic line shown by a dotted line in FIG. 5 It becomes impossible to actually inject the fuel of the amount T _is .

In particular, in the above-mentioned prior art, the first and second injection valves share the premixing ratio ε, and the following (1), (2),
As shown in the equations (3) and (4), since the fuel is injected as the planned injection amounts T _im and T _is , when the premix ratio ε is set small, for example, about 0.3, The planned injection amount T _{is of} the second injection valve may become the low level T _isL or less. Then, in this case, the actual actual injection amount sharply decreases as indicated by the solid line in FIG. 5, and therefore the fuel corresponding to the entire planned injection amount (T _im + T _is ) required by the entire engine _{is obtained.} However, there is a problem that the engine cannot be actually supplied to the engine, the mixture ratio of the fuel to the air (air-fuel ratio) becomes lean, and the rotational fluctuation of the engine becomes large.

The present invention has been made in view of the above-described problems of the prior art, and the present invention can appropriately increase or decrease the injection amount of fuel injected from the first and second injection valves according to the operating state of the engine, Overall expected injection amount required by (T _im + T _is )
You can always secure enough fuel to supply to the engine,
(EN) A fuel injection device capable of reliably atomizing premixed fuel injected from a second injection valve by an ultrasonic oscillator and effectively reducing fluctuations in engine rotation.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention provides a first injection valve which is provided in each branch pipe of an intake pipe and injects fuel into each cylinder of an engine, and a first injection valve which is provided in a collector of the intake pipe to perform premixing. Second injection valve for injecting fuel for fuel, and the second
Of the ultrasonic injector, which is provided in the collector of the intake pipe in opposition to the injection valve of No. 3, and atomizes the fuel injected from the second injection valve, and the planned injection amount (T _im ),
(T _is ) _is calculated according to the operating state of the engine, and the planned injection amount (T _is ) of the second injection valve calculated by the calculating unit _is equal to or lower than a predetermined low level (T _isL ). Or
Level determination means for determining whether the level is higher than a predetermined high level (T _isH ), and when the level determination means determines that the level is lower than (T _isL ), the actual fuel injection by the second injection valve is stopped. , The total planned injection amount from the first injection valve (T
The first fuel injection amount correction means for actually injecting the fuel of _im + T _is ) and the actual fuel injection by the second injection valve when the level determination means determines that the fuel level is higher than (T _isH ). _Is gradually increased from the low level (T _isL ), and an injection amount of fuel obtained by subtracting the gradual increment from the total planned injection amount (T _im + T _is ) _is actually injected by the first injection valve. And a second injection amount correction means for
When the actual injection amount by the injection valve of No. 1 gradually increases and reaches the planned injection amount (T _is ), the actual injection amount by the first injection valve is returned to the planned injection amount (T _im ). The following configuration is adopted.

[Action]

With the above configuration, when the level determination means determines that the planned injection amount (T _is ) by the second injection valve _is equal to or lower than the low level (T _isL ), the first injection amount correction means determines the actual injection amount by the second injection valve. the fuel injection is stopped, scheduled injection amount of the whole by connexion to the first injection valve because to actually inject (T _im + T _is) worth of fuel planned injection amount of total required in the entire engine (T _im + T The fuel for _is ) can be secured on the side of the first injection valve, and the required amount of fuel can be reliably supplied to the engine.

Further, when the level determination means determines that the planned injection amount (T _is ) by the second injection valve becomes _{equal to} or higher than the high level (T _isH ), the second injection amount correction means actually determines by the second injection valve. Fuel injection is started from the low level (T _isL ) to be gradually increased, and the injection amount of fuel obtained by subtracting this gradual increment from the total planned injection amount (T _im + T _is ) _{is actually supplied} by the first injection valve. Since the fuel is injected, even in this case, the fuel of the entire planned injection amount (T _im + T _is ) required for the entire engine can be injected and supplied by the first and second injection valves, and at the same time, the second
When the actual injection amount of the first injection valve gradually increases and reaches the planned injection amount (T _is ), the actual injection amount of the first injection valve is returned to the planned injection amount (T _im ).
It is also possible to suppress a sudden change in the actual injection amount of the first and second injection valves.

Then, when the fuel is actually injected from the second injection valve, the injected fuel can be reliably atomized by the ultrasonic transducer, and the fuel for premixing is directed from the collector side of the intake pipe to each cylinder side of the engine. Can be supplied in the atomized state.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

In the figure, reference numeral 1 denotes an engine body of an automobile. The engine body 1 burns a mixture of fuel and intake air sucked from an intake pipe 2 side described later in each cylinder 1A (for example, 4 cylinders) to produce a crankshaft. The rotation output is derived from 1B. Reference numeral 2 denotes an intake pipe connected to the intake side of the engine body 1, an air cleaner 3 is provided at the tip side of the intake pipe 2, and an air flow meter 4 for detecting the intake air amount Q is provided downstream of the air cleaner 3. , And a throttle valve 5 for controlling the intake air amount Q according to the opening degree.

Here, in the intake pipe 2, the downstream side of the throttle valve 5 becomes a collector 2A as an intake reservoir, and the collector 2A
, The branch pipes 2B, 2B, ... Which branch into, for example, four branches and communicate with the inside of each cylinder 1A of the engine body 1 constitute an intake manifold. Further, a throttle valve switch 5A (including a throttle sensor) is attached to the throttle valve 5, and the switch 5A outputs a signal according to the opening degree of the throttle valve 5 to a control unit 11 described later. There is. A crank angle sensor 6 that outputs the engine speed N is provided near the crankshaft 1B. Reference numeral 7 denotes an exhaust pipe connected to the exhaust side of the engine body 1 for exhausting exhaust gas to the outside.

Reference numerals 8, 8, ... Depict first injection valves provided in each branch pipe 2B of the intake pipe 2 for injecting fuel into each cylinder 1A. Each injection valve 8 has a built-in electromagnetic actuator or the like and controls. When the injection pulse S _m (see FIG. 2) is applied from the unit 11, the fuel is injected into each branch pipe 2B. Here, the pulse width of the injection pulse S _m is determined based on the planned injection amount T _im according to the calculation formula (3) described later, and each injection valve 8
_Injects fuel corresponding to the planned injection amount T _im in the vicinity of each cylinder 1A to improve the distribution performance of the air-fuel mixture and the like.

Reference numeral 9 denotes a second injection valve provided in the collector 2A of the intake pipe 2, and the injection valve 9 has a built-in electromagnetic actuator or the like,
When the injection pulse S _s is applied from the control unit 11, the fuel for premixing is injected from the injection nozzle 9A into the collector 2A with the characteristics shown by the solid line in FIG. Here, the pulse width of the injection pulse S _{s is} determined based on the planned injection amount T _is according to the calculation formula (4) described later, and the injection valve 9 supplies the fuel corresponding to the planned injection amount T _is from the injection nozzle 9A to the later described. It is jetted toward the diaphragm 10A of.

Reference numeral 10 denotes an ultrasonic oscillator provided in the collector 2A so as to face the injection nozzle 9A of the injection valve 9, and a vibration plate 10A curved in a semicircular shape is provided at the tip side of the ultrasonic oscillator 10. ,
By applying a high frequency voltage V from the control unit 11 to the piezoelectric element 10B on the base end side of the diaphragm 10A, for example,
With a predetermined frequency of about 30～50KH _z adapted to ultrasonic vibration. Then, the diaphragm of the ultrasonic transducer 10
10A atomizes the fuel for premixing injected from the injection valve 9 by ultrasonic vibration until the particle size becomes, for example, about 10 to 30 μm, and each branch pipe 2B in a state where the fuel and the intake air are uniformly premixed. Inhale to the side.

Further, reference numeral 11 denotes a control unit constituted by a microcomputer or the like, and the control unit 11 is, as shown in FIG. 2, an input / output control circuit 12, for example, a processing circuit 13 including a CPU, MPU, etc. It is configured to include a memory circuit 14 including the above. The input side of the input / output control circuit 12 is connected to the air flow meter 4, the crank angle sensor 6, the start switch 15, the throttle valve switch 5A, etc., and the output side is connected to the first injection valves 8,
It is connected to the second injection valve 9 and the ultrasonic transducer 10 and outputs the injection pulses S _m and S _s and the high frequency voltage V to them.

And the control unit 11 is the air flow meter 4
From the intake air amount Q by the crank angle sensor 6 and the engine speed N by the crank angle sensor 6, the basic injection amounts T _pm , T _ps of the first injection valve 8 and the second injection valve 9 are However, K: constant K ^# : calculated as the ratio of the basic pulse width of the injection valve 8 and the injection valve 9, and the effective injection amount T by each injection valve 8 and 9
_em , T _es However, α: Air-fuel ratio feedback correction coefficient α ': Basic air-fuel ratio learning correction coefficient C _oef : Various correction coefficients ε: Calculated as a premix ratio, and based on this calculation result, T _im = T _em + T _sm ...... (3 ) T _is = T _es + T _ss (4) where, T _sm , T _ss : injection pulses S _m , S _s corresponding to the planned injection amount T _im , T _is, which _{is the} voltage correction coefficient, to the injection valves 8 and 9. Output. Here, the premix ratio ε is determined by the injection valves 8, 9
Represents the share of the fuel injection amount. Also, the voltage correction factor T _sm, T _ss than those falling under the effective injection quantity T _em, invalid pulse width when the effective pulse width T _es, effective injection quantity T _em, T
It is a correction coefficient for injecting the fuel of the flow rate corresponding to _es .

A program for injection amount control processing shown in FIG. 3 is stored in the memory circuit 14 of the control unit 11, and is output to the second injection valve 9 in the memory area 14A of the memory circuit 14. In the range of the injection amount T _{is which} can be controlled in proportion to the pulse width of the injection pulse S _s , the lowest level low level injection amount T _isL (hereinafter referred to as the low level T as shown in FIGS. 4 and 5). a) that _isL, predetermined amount increased, predetermined high level injection quantity T _ISH (hereinafter than low level T _isL, a high-level T that _ISH) or the like are stored.

The fuel injection device according to the present embodiment has the above-mentioned configuration. Next, the injection amount control process by the control unit 11 will be described with reference to FIGS. 3 to 5.

First, when the processing operation is started by turning on the start switch 15, in step 1, the above (1), (2),
Based on the equations (3) and (4), the planned injection amounts T _im and T _is of the first and second injection valves 8 and 9 are calculated, and the process proceeds to step 2 to perform a flag process (not shown) by another routine. It is determined whether the determined flag F is “0” or “1”, and when the flag F is determined to be “0”, the process _proceeds to step 3 to determine whether the planned injection amount T _is is the low level T _isL or less. Determine whether or not. When it is determined as "NO" in step 3, scheduled injection amount T _IS is greater than the low level T _isL, because it can be determined to be in the illustrated region I in FIG. 4, first in step 7, the second The actual injection amount T _m , T _s (hereinafter referred to as the actual injection amount T _m , T _s ) by the injection valves 8 and 9 of As a result, the fuel of the actual injection amounts T _m and T _s corresponding to the planned injection amounts T _im and T _{is is} injected from the first and second injection valves 8 and 9, respectively.

Further, when it is determined to be “YES” in step 3, the planned injection amount (T _is ) by the second injection valve 9 is at the low level T _isL.
Below (see region II in FIG. 4), as indicated by the solid line in FIG. 5, the fuel of the planned injection amount T _is proportional to the pulse width of the injection pulse S _s is supplied from the second injection valve 9. In actuality, injection becomes impossible, so move to step 4 to correct the actual injection amounts T _m and T _s of the first and second injection valves 8 and 9, As a matter of fact (however, the actual injection amount T _m is a value ignoring the constant K ^# ), the actual fuel injection by the second injection valve 9 is stopped, and the first and second injection valves 8, 9 are The fuel _is injected from the first injection valve 8 by adding the fuel of the planned injection amounts T _im and T _is to be injected, and the entire planned injection amount (T _Im + T _is ) fuel is injected and supplied. Then, the process proceeds to step 5, the flag F is set to "1", the process returns at step 6, and the processes after step 1 are continued.

Next, when the flag F is determined to be "1" in step 2, the process proceeds to step 8 and the planned injection amount T _is is high level T.
_When it is determined whether or not _isH or more, and when it is determined to be "NO", the planned injection amount T _is is less than the high level T _isH , which corresponds to the region II shown in FIG. First,
The actual injection amounts T _m and T _s by the second injection valves 8 and 9 are corrected in the same manner as in the equation (6), the actual fuel injection by the second injection valve 9 is stopped, and the first injection valve 8 The fuel of the entire planned injection amount (T _im + T _is ) required by the engine body 1 is injected only from this.

Further, when it is determined to be “YES” in step 8, the planned injection amount T _is becomes higher than the high level T _isH and corresponds to the region III shown in FIG.
In order to correct the actual injection amount T _m , T _s by the first and second injection valves 8 and 9, However, C: counter (C = 0, 1, 2 ...) P: increase rate (for example, P = 0.2), the actual injection amount T _s of the second injection valve 9 is set to a predetermined low level.
From T _isL , the counter C outputs the reference signal of the crank angle sensor 6 (a signal output every time the crankshaft 1B rotates 180 degrees).
For example, (T _is −T _isL ) × C ×
Gradually increase by 0.2. Then, the constant K ^# is ignored so that the amount of fuel obtained by subtracting the gradual increase is injected from the first injection valve 8, and the actual injection amount T _{m is set} to the injection amount (T _im + T _is −T _{Every time the} counter C is _stepped from ( _isL ), it is gradually decreased by, for example, (T _is −T _isL ) × C × 0.2.

Next, in step 11, the actual injection amount by the second injection valve 9
It _is determined whether T _s has exceeded the planned injection amount T _is and
When it is determined to be "S", the planned injection amount T _is is in the region shown in FIG.
Since it has reached IV, the routine proceeds to step 12, where the actual injection amounts T _m , T _s by the injection valves 8 and 9 are returned to the original planned injection amounts T _im , T _is , as in the above equation (5). In step 13, the flag F is set to "0" again, and in step 14, the counter C is set to zero. Then, the process proceeds to step 6 and returns. By the flag processing, the flag F is set to "0" when the planned injection amount Tis _is in the regions I and IV in FIG. 4, and is set to "1" when it is in the regions II and III. It

Thus, according to the present embodiment, the planned injection amount T by the second injection valve 9 calculated based on the above equations (1) to (4).
_{When is} is equal to or lower than the low level T _isL by setting the premix ratio ε (0 <ε ≦ 1) to about 0.3, the actual fuel injection by the second injection valve 9 is stopped, and Since the fuel is injected from the injection valve 8 of No. 1 as much as the total planned injection amount (T _im + T _is ) required by the engine body 1, the total planned injection amount of the injection valves 8 and 9 (T _im + T is The fuel for _is ) can be always secured, and as described in the related art, it is possible to effectively reduce the increase in engine rotation fluctuation due to the lean air-fuel ratio.

Further, when the planned injection amount T _is becomes _{equal to} or higher than the predetermined high level T _isH , the actual injection amount T _s by the second injection valve 9 is _calculated by the equation (7) as shown in the region III in FIG. Is gradually increased and the actual injection amount T _m by the first injection valve 8 is gradually decreased, it is possible to prevent the actual injection amounts T _m and T _s from changing rapidly, and at the same time, the actual injection amount T _s can be prevented. Is the planned injection amount T
when titrated to an amount corresponding to the _IS is _an area in FIG. 4
As shown in IV, the actual injection amount T _m , T _{s is changed} to the original planned injection amount T _im , T
_{It is possible} to return to is, and it is possible to actually inject the amount of fuel corresponding to the planned injection amounts T _im and T _is from the first and second injection valves 8 and 9.

When the fuel is injected from the second injection valve, the injected fuel can be atomized by the ultrasonic vibrator 10, so that the premixing is performed from the collector 2A side of the intake pipe 2 toward each cylinder 1A side of the engine body 1. It is possible to supply the fuel for use in the atomized state, and it is possible to greatly improve the idle stability and transient response.

In the above-mentioned embodiment, in the program shown in FIG. 3, step 1 is a specific example of the injection amount calculation means that is a constituent feature of the present invention, and steps 3 and 8 are specific examples of the level determination means, Steps 4 and 9 are specific examples of the first injection amount correction means, and step 10 is a specific example of the second injection amount correction means.

In the above embodiment, the counter C is set to 0, 1, 2, 3, ... In step 10 shown in FIG.
Although it has been described that the steps are sequentially performed each time the 180-degree reference signal is output, instead of this, in step 8, "YE
When it is determined to be "S", first, the counter C is set to C = 1,
Then, each time the crank angle sensor 6 outputs a reference signal, the counter C may be set to C = 2, 3, ...

〔The invention's effect〕

As described above in detail, according to the present invention, when the planned injection amount (T _is ) of the second injection valve becomes equal to or lower than the predetermined low level (T _isL ), the actual fuel injection by the second injection valve is performed. While stopping, the entire planned injection amount (T
_Im + T _is ) fuel is injected, and when it becomes higher than the high level (T _isH ), the actual fuel injection by the second injection valve is started to gradually increase from the low level (T _isL ),
From the first injection valve, the injection amount of fuel obtained by calculating this gradual increment from the planned injection amount (T _im + T _is ) _is actually injected, whereby the actual injection amount from the first and second injection valves is Since the configuration is designed to prevent sudden changes, it is possible to always secure the fuel for the entire planned injection amount (T _im + T _is ) required for the entire engine and supply it to the engine, and the air-fuel ratio becomes lean. In addition to preventing large fluctuations in engine speed,
It is possible to suppress a sudden change in the actual injection amount by the first and second injection valves, and improve the atomization and mixing property of the fuel.

An ultrasonic oscillator is provided in the collector of the intake pipe so as to face the second injection valve for injecting the fuel for premixing, and the injected fuel from the second injection valve is atomized by the ultrasonic oscillator. When the fuel is actually injected from the second injection valve, the injected fuel can be effectively atomized by the ultrasonic vibrator, and the fuel can be atomized from the collector side of the intake pipe to each cylinder side of the engine. Therefore, the fuel for premixing can be supplied in the form of atomized particles, which can greatly improve the idle stability and transient response of the engine.

[Brief description of drawings]

FIG. 1 is an overall view of a fuel injection device showing an embodiment of the present invention,
2 is a block diagram showing the circuit configuration of the control unit, FIG. 3 is a flow chart showing the injection amount control processing, and FIG. 4 is a characteristic diagram showing the injection amount control characteristic of the second injection valve.
FIG. 5 is a characteristic diagram showing the injection characteristic of the second injection valve. 1 ... Engine body, 1A ... Cylinder, 2 ... Intake pipe,
2A: collector, 2B: branch pipe, 8: first injection valve,
9 ...... second injection valve, 10 ...... ultrasonic transducer, 11 ...... control unit, T _im, T _IS ...... planned injection quantity, T _isL ......
Low level injection amount (low level), T _isH …… High level injection amount (high level), T _m , T _s …… Actual injection amount.

Claims (1)

[Claims] 1. A first injection valve provided in each branch pipe of the intake pipe for injecting fuel into each cylinder of the engine; and a first injection valve provided in the collector of the intake pipe for injecting fuel for premixing. A second injection valve, an ultrasonic transducer that is provided in the collector of the intake pipe facing the second injection valve and atomizes the fuel injected from the second injection valve; Injection amount (T _im ) and (T _is ) of the injection valve of the second injection valve, which are calculated by the calculation unit, and the injection amount of the second injection valve (T _im ) _is ) is equal to or lower than a predetermined low level (T _isL ), or is equal to or higher than a predetermined high level (T _isH ), and when the level determination means determines that the level is lower than (T _isL ), The actual fuel injection by the second injection valve is stopped, and the total planned injection amount (T The first fuel injection amount correction means for actually injecting the fuel of _im + T _is ) and the actual fuel injection by the second injection valve when the level determination means determines that the fuel level is higher than (T _isH ). To gradually increase from the low level (T _isL ), and the total planned injection amount (T _im +
And a second injection amount correction means for actually injecting the fuel of the injection amount obtained by subtracting the gradual increment from T _is ) by the first injection valve, and the actual injection amount by the second injection valve is gradually increased. Then, when the planned injection amount (T _is ) is reached, the fuel injection device configured to restore the actual injection amount by the first injection valve to the planned injection amount (T _im ).