JPH02215942A - Fuel supply method and device - Google Patents

Abstract

PURPOSE:To improve a mixing characteristic of air-fuel mixture as well as to aim at the promotion of lean combustion and reduction in fuel consumption by making a partial cylinder fuel injection valve and premixed fuel injection valve take partial charge of a fuel quantity corresponding to a request air-fuel ratio for partial load driving or the like on the basis of a setting ratio. CONSTITUTION:A premixed fuel injection valve 12 is used in combination with a partial cylinder fuel injection valve 11 at a time when it is at least in a partial load driving area of an engine, whereby a fuel quantity corresponding to a request air-fuel ratio of the engine is alloted and sprayed on the basis of the setting ratio of both these valves. At this time, each fuel injection timing of these valves 11, 12 provides a phase difference in consideration of flow delay time of fuel. With this constitution, the premixed fuel injection valve 12 sprays the fuel quantity allotted at a setup position of the partial cylinder fuel injection valve 11 and an intake passage 16 at the more upstream than an intake manifold 15. This fuel is premixed with air in the intake passage 16 before reaching to an intake port of the engine, and it is distributed to each cylinder 13 of the engine together with a fuel spray out of the partial cylinder fuel injection valve 11 on an air flow in the intake passage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multi-point fuel injection (MPI) fuel supply method and apparatus.

[Conventional technology]

BACKGROUND ART Conventionally, for example, in the field of automobiles, fuel supply devices of a multi-point fuel injection type, in which a fuel injection valve is arranged for each cylinder of a multi-cylinder engine, have been widely put into practical use. This type of fuel supply system includes (1) electrically controlled fuel injection valves (cylinder-specific fuel injection valves) near the intake valves of each cylinder of the engine, as disclosed in, for example, Japanese Unexamined Patent Publication No. 53-1723. The injection time width (fuel amount) of the fuel injection valve is duty-controlled according to the operating state of the engine, and fuel corresponding to the required mixture ratio (air-fuel ratio) is supplied.

Thanks to advances in electronic control technology, these fuel injection valves can change the amount of fuel injected depending on the engine operating status.
Make the required air-fuel ratio lean or rich
It has the advantage of being controllable, purifying engine exhaust gas, and improving fuel efficiency.

In addition, in conventional devices of this type,
In addition to the fuel injection valves for each cylinder, as disclosed in Japanese Patent No. 9, there is a system in which one common fuel injection valve for low-temperature starting is provided upstream of the intake manifold of each cylinder (upstream of the manifold gathering part). This injection valve for cold starting is activated only during cranking when starting the engine, and has the role of increasing the amount of fuel at the time of starting, enriching the air-fuel mixture to a predetermined value, and smoothing the cold starting.

[Problem to be solved by the invention]

By the way, among the operating conditions of an automobile engine, so-called partial load operation is used most frequently, so purification of exhaust gas and improvement of fuel efficiency are particularly required, and it is necessary to operate at a lean air-fuel ratio as much as possible. desired.

When operating an engine at such a lean air-fuel ratio, it is necessary to improve the mixing characteristics of fuel and air.
This type of fuel injection method opens fuel injection valves for each cylinder near the intake valve for a predetermined period at a predetermined crank angle to inject fuel.
The concentration of the air-fuel mixture supplied to the combustion chamber is not uniform over time, making it difficult to form a homogeneous air-fuel mixture inside the combustion chamber as in a carburetor. This tendency becomes particularly noticeable when the injection valve opening time is short, that is, during low-speed, light-load operation, and becomes a cause of impeding improvement in combustion stability and lean operation. Furthermore, poor mixing of the air-fuel mixture causes a so-called fuel breathing phenomenon during transient operation such as acceleration from low speed to high speed, which reduces engine response (output responsiveness) and adversely affects combustion.

The present invention has been made in view of the above points, and its purpose is to improve the mixing characteristics of the air-fuel mixture and to significantly improve the operability at lean air-fuel ratios (lean burn) such as during partial load operation. It is an object of the present invention to provide a fuel supply method and device that can be improved, purify exhaust gas, and improve fuel efficiency.

[Means to solve the problem]

In order to achieve the above object, the present invention first provides the following fuel supply method.

That is, the present invention is an apparatus for supplying injected fuel to an engine using fuel injection valves, and has cylinder-specific fuel injection valves arranged for each cylinder of a multi-cylinder engine. A premix fuel injection valve that is common to all cylinders and forms an air-fuel mixture in advance is installed in the installation position of the engine and in the intake passage upstream of the intake manifold. When used in conjunction with a cylinder-specific fuel injection valve, the fuel amount corresponding to the required air-fuel ratio of the engine is shared between the cylinder-specific fuel injection valve and the premix fuel injection valve based on a set ratio.

In addition, as a device for carrying out such a fuel supply method, 1
We provide a device with the following configuration.

In other words, in a device that supplies injected fuel to an engine using fuel injection valves, there are two types of fuel injection valves: cylinder-specific fuel injection valves arranged for each cylinder of a multi-cylinder engine, and these cylinder-specific fuel injection valves! ? ! A premix fuel injection valve that is common to each cylinder and is disposed in an intake passage upstream of the intake manifold, and that forms an air-fuel mixture in advance upstream of the intake manifold.

A control means for changing the ratio of the amount of fuel metered and injected by the cylinder-specific fuel injection valve and the amount of fuel metered and injected by the premix fuel injection valve according to the engine operating state.

Further, the control means employs proportional and integral control methods for the cylinder-specific fuel injection valves and the premixed fuel injection valves.

Differential elements are introduced, and constants of these control elements are set to be different between the cylinder-specific fuel injection valve and the premixed fuel injection valve.

[Effect]

According to the fuel supply method of the present invention, the premix fuel injection valve is used together with the cylinder-specific fuel injection valve at least when the engine is in a partial load operating range. And with this combination,
The amount of fuel corresponding to the required air-fuel ratio of the engine is divided and injected between the cylinder-specific fuel injection valve and the premix fuel injection valve based on a set ratio.

In this case, it is preferable to provide a phase difference between the fuel injection timings (valve opening timings) of the premixed fuel injection valve and the cylinder-specific fuel injection valves in consideration of the fuel flow delay time6. The injection valve is operated at every predetermined engine crank angle in the same way as the cylinder-specific fuel injection valve, and its opening timing is slightly earlier than that of the corresponding cylinder-specific fuel injection valve each time. Further, the number of operations is multiplied by the number of cylinders, such as 4 times for a 4-cylinder engine and 6 times for a 6-cylinder engine, relative to the fuel injection valve for each cylinder.

In this way, the premixed fuel injection valve injects the amount of fuel distributed between the cylinder-specific fuel injection valve installation position and the intake passage upstream of the intake manifold, and this injected fuel reaches the intake boat of the engine. The mixture is thoroughly mixed with the air in the intake passage beforehand, and this air-fuel mixture rides on the airflow in the intake passage and is distributed to each cylinder of the engine together with the fuel spray injected from the cylinder-specific fuel injection valve. As a result 1. Electronic multi-point fuel injection devices that intermittently inject fuel and supply a mixture to the engine also supply the engine with a mixture that is temporally and spatially uniform to the same degree as a carburetor. can do. Therefore, combustion stability is improved accordingly, lean combustion can be achieved through partial load operation, etc., and exhaust gas purification and fuel consumption reduction can be achieved. In addition, even during transient operation when accelerating from low speed, if the premixed fuel is sent to the engine combustion chamber when increasing the amount of fuel, it is possible to prevent the mixture from being interrupted during acceleration operation.
It is possible to eliminate this problem (breathing) and smoothen transient operation. Note that the sharing ratio of the amount of fuel injected by the cylinder-specific fuel injection valve and the premix fuel injection valve is preferably changed depending on the operating state of the engine. The reason for this will be explained in the operation of the device below.

Here, a detailed explanation will be given of the invention related to an apparatus for carrying out the above fuel supply method.

Generally, when controlling the fuel amount according to the required air-fuel ratio using a fuel injection valve, an air-fuel ratio sensor (O
Feedback control is performed based on the detection signal of x sensor), and in this control, proportional (P), integral (I
), a differential (D) element, and is performed by changing the P, I, and D values according to the engine operating conditions (this is referred to as control rather than P).

In the present invention, the fuel amount is controlled according to the engine operating conditions (required air-fuel ratio) by using the cylinder-specific fuel injection valve and the premix fuel injection valve together, but in this case, the cylinder-specific fuel injection valve is of course used. The above-mentioned PID control is also performed in the premix fuel injection valve. However, P and I of the cylinder-specific fuel injection valve and the premixed fuel injection valve.

The constant of the D element corresponds to the sharing ratio of each fuel amount,
are set differently from each other. These PID values change depending on the engine operating conditions, and in this way, the ratio between the amount of fuel measured and injected by the fuel injection valve for each cylinder and the amount of fuel measured and injected by the premix fuel injection valve is determined by the speed and load. etc., depending on the engine operating conditions. By controlling in this way, the fuel injection valves for each cylinder are controlled during partial load operation, etc.

Fuel is injected from the premix fuel injection valve at a ratio that matches the operating state.

Measurement is performed using cylinder-specific combustion fuel injection valves and premixed fuel injection valves.

The reason why the ratio of the amount of fuel injected is changed depending on the operating state of the engine is as follows.

In other words, it is ideal that the premix ratio (the proportion of fuel injected from the premix fuel injection valve) be large throughout the entire operating range, but as the engine speed increases,
Especially at high speeds and high loads.

The injected fuel from the premix fuel injection valve is likely to be inhaled into cylinders other than the predetermined ones, resulting in a problem that the air-fuel mixture concentration between the cylinders, that is, the air-fuel ratio deviation becomes large. Also,
In high-speed, high-load ranges, the air flow rate entering the combustion chamber also increases, which promotes atomization of the fuel injected from the cylinder-specific combustion fuel injection valve near the intake valve. Therefore, in such high-speed, high-load ranges, by reducing the premix ratio, the air-fuel ratio deviation between cylinders is reduced, and the air-flow atomization improves the formation of the air-fuel mixture that flows into the combustion chamber. is the most effective.

On the other hand, in the partial load operating range, the above-mentioned air-fuel ratio deviation is not significant, and the premix ratio can be made relatively large. This premixing ratio can be arbitrarily set, but to give a numerical example, it is 50 to 60% in a 1 part load operating range, and 0 to 20% in a high speed, high load operating range.

In addition, in the early days of fuel supply systems using conventional fuel injection valves, a starting valve for low-temperature starting of the engine was installed upstream of the combustion fuel injection valve for each cylinder, as in the above-mentioned Japanese Patent Application Laid-Open No. 52-145629. There is something. This is intended to increase the amount of fuel solely for the purpose of improving combustion when starting the engine at a low temperature.1 According to the engine operating conditions such as partial load operation as in the present invention,
There is nothing to be said about sharing the amount of fuel corresponding to the required air-fuel ratio between cylinder-specific combustion fuel injection valves and premixed fuel injection valves based on a set ratio, or improving the air-fuel mixture characteristics required for lean-burn operation. The present invention does not include consideration of
It should be noted that they are technically different.

〔Example〕

An embodiment of the present invention will be described based on the drawings.

FIGS. 1 and 2 are system configuration diagrams showing one embodiment of the present invention.

In the figure, 11 is a combustion fuel injection valve for each cylinder, and 12 is a premix fuel injection valve.

The cylinder-specific combustion fuel injection valves 11 are arranged near the intake valves 14 of each intake manifold for each cylinder 13 of a multi-cylinder engine as shown in FIG. The cylinder-specific combustion fuel injection valves 11 are four in total.

The premixed fuel injection valve 12 includes an intake passage 16 upstream of the fuel injection valve 11 for each cylinder and the intake manifold 15;
In other words, the throttle valve 1 is connected to the unified intake passage 16 before branching.
7 is disposed at a position downstream from 7, and is common to each cylinder. Fuel is injected at this position and mixed in advance (premixing) in the intake passage.

Next, a control system for the cylinder-specific combustion fuel injection valve 11 and the premix fuel injection valve 12 will be explained.

1 is an intake sensor that detects the intake air amount of the engine (not shown), 2 is a sensor that detects the engine rotation speed, 2' is a crank angle sensor, and 3 is a unit that controls fuel injection (
microcomputer).

The control unit 3 includes a circuit 4 that calculates the basic fuel injection time Tp from the signal Qa of the intake sensor 1 and the signal N of the rotation speed sensor 2, and a circuit 4 that calculates the basic fuel injection time Tp based on the signal Qa of the intake sensor 1 and the signal N of the rotation speed sensor 2. A memory device (ROM) 5 that stores the pulse #i) in Tp-N compares the signal of the air-fuel ratio sensor 8 with the selected injection time 1 (fuel injection amount), and adjusts the fuel so that a predetermined air-fuel ratio is achieved. a circuit 6 for correcting and calculating the injection amount;
PI of cylinder-specific combustion fuel injection valve 11 and premix fuel injection valve 12
It is composed of a circuit 7 that performs calculations necessary for D control, a circuit 9 that performs PID control of the cylinder-specific combustion fuel injection valve 11, and a circuit 10 that performs PID control of the premix fuel injection valve 12.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG. 81 to 87 in FIG. 5 represent steps.

When the engine is running, the intake air amount signal Qa of the intake sensor 1
Based on the engine rotational speed signal N of the rotational speed sensor 2, a basic fuel injection time 'rp is calculated in the basic injection time calculation circuit 4 in the arithmetic unit 3, and the result and the engine rotational speed N are stored in the storage device 5. The fuel injection time width that meets the conditions is selected from the Tp-N data obtained (Sl, S2), and low temperature start is performed in S3.

It is determined whether or not it is in a so-called normal operating range other than acceleration driving, etc., and if it is in the normal operating range, air-fuel ratio feedback control by the S4 Oz sensor is executed, and the selected fuel time width and the signal from the 02 sensor 8 are The arithmetic circuit 6 compares the air-fuel ratio with the air-fuel ratio, corrects the fuel injection time width so as to achieve a predetermined air-fuel ratio, and sends a signal to the next arithmetic system 7 (S4).

Then, in S5, the corrected fuel injection time width is distributed to the cylinder-specific fuel injection valve 11 and the premix fuel injection valve 12 at a ratio set corresponding to the engine state, and the cylinder-specific fuel injection valve 11 and the premix fuel injection valve Each of the fuel injection valves 12 is proportional (P)
, integral (1), and differential (D) elements are performed (86).

Here, the cylinder-specific fuel injection valve 11 and the premixed fuel injection valve 12
PID control is performed using different constants for the P, I, and D values. This is because the position of the injection valve, the atomization level, and the amount of fuel injection per unit time are different. Also, these P, I.

The D value changes depending on engine operating conditions such as low speed/light load operation such as idling operation, partial load operation, high speed/high load operation, etc., and in this way, the fuel is metered and injected by the cylinder-specific fuel injection valve 11. The amount of fuel is measured by the premixed fuel injection valve 12,
The ratio to the amount of fuel injected is changed depending on the engine operating state.

Therefore, since the premixed fuel injection valve 12 is arranged in the intake passage upstream of the installation position of the cylinder-specific fuel injection valve 11 and the intake manifold, the fuel of the premixed fuel injection valve 12 injected from this position is injected into the engine. The air-fuel mixture is sufficiently premixed with the air in the intake passage before reaching the intake port, and this air-fuel mixture merges with the fuel spray injected from the cylinder-specific fuel injection valve 11.

distributed to each cylinder of the engine.

In this embodiment, as described above, the calculation system 7 allocates the injection time @ (fuel injection amount) of each cylinder fuel injection valve 11 and premix fuel injection valve 12, but the setting of the ratio is A specific example will be described later.

In addition, in operating ranges (outside normal operating ranges) where rich combustion operation using open-loop control is required, such as acceleration driving,
The mode changes from 83 to 87 in FIG. 5, and the fuel amount (fuel injection time @) is increased in accordance with the operation.

A time chart of one hour of opening timing of the premix fuel injection valve 12 and the cylinder-specific fuel injection valve 11 in the partial load operation in the normal operation range executed in step 85 is shown in FIG. FIG. 3 illustrates the case of a 4-cycle 4-cylinder engine, in which the opening pulse of the premixed fuel injection valve 12 is set to (,),
(b) to (a) The valve opening pulse of the fuel injection valve 11 for each cylinder
Shown below.

(b) is the opening pulse of the fuel injection valve 11 for the first cylinder, (C) is the third cylinder, (d) is the fourth cylinder, and (e) is the valve opening pulse of the fuel injection valve 11 for the second cylinder. In FIG. 3, the opening timing of the fuel injection valve is determined individually for each cylinder. Let us take the so-called sequential injection method as an example.

That is, for every crank angle of 1800, the valve opening pulse Tiz of the fuel injection valve 11 of the first cylinder, the valve opening pulse Ti8 of the fuel injection valve 11 of the third cylinder, and the valve opening pulse Ti8 of the fuel injection valve 11 of the fourth cylinder are
The control device 3 sequentially generates a valve opening pulse Ti+ for the fuel injection valve 11 of the second cylinder and a valve opening pulse T i z for the fuel injection valve 11 of the second cylinder, and sends the signal to each fuel injection valve 11 to inject a predetermined amount of fuel.

When the premixed fuel injection valve 12 according to the present invention is used in combination during normal operation such as partial load operation, the fuel amount Qfi from each cylinder fuel injection valve 11 and the fuel amount Qfp from the premixed fuel injection valve 12 Qfi and Qfp are determined so that the sum of Qfi and Qfp is the same as the conventional amount of fuel from one fuel injection valve near the intake valve of each cylinder (the amount of fuel corresponding to the required air-fuel ratio). Therefore, the premixed fuel injection valve 12
The valve opening pulse Tpi is generated every 180° of the crank angle.For example, the pulses Tpil and Til shown in the figure cause the fuel Qfp and Qfi to be released from the premixed fuel injection valve 12 and the cylinder-specific fuel injection valve 11 of the first cylinder. quantity is supplied to the first cylinder. Similarly, from the next pulse of TPi8 and Tiδ,
Premixed fuel injection valve 12 and cylinder-specific fuel injection valve 1 of the third cylinder
1 to Qfp and Qfi are supplied to the third cylinder. Similarly, from the next pulses of T p i a and T i a, the fuel amounts of Qfp and Qfi are transferred to the 4th cylinder, and
Pit and Ti! From the pulse, fuel quantities Qfp and Qfi are supplied to the second cylinder. In order to change the ratio between the fuel amount Qfp from the premix fuel injection valve 12 and the fuel amount Qfi from the fuel injection valve 11 for each cylinder, the pulse width Tpi and Ti
This can be easily done by changing the ratio T p i /T i . Here, this ratio will be referred to as premix ratio φP.

In addition, a premix fuel injection valve 12 and a fuel injection valve 11 for each cylinder
The opening timing of the two injection valves is determined by setting a phase difference of 61 hours as shown in the figure, taking into account the flow delay time of the fuel to the combustion chamber. It is important to make the air concentration as uniform in time and space as possible. Therefore, it is necessary to change the phase difference ΔT depending on the magnitude of the intake air flow rate Qa and take into account the flow delay.

In addition, in the premixing of the present invention, fuel is injected from the fuel injection valves 11 simultaneously in each cylinder instead of the sequential injection method shown in FIG. A so-called simultaneous injection method or a group injection method in which injection is performed for each cylinder group can be performed in substantially the same manner, but the explanation will be omitted here.

FIG. 4 shows a premix ratio φP map for engine operating conditions. The premixing ratio is φPl>φpx>φp
a>φP number>φps>φP6.

In other words, the premixing ratio φP is the highest in the partial operating range, the premixing ratio φP is slightly smaller in the lower speed and light load ranges, and the premixing ratio φP is as small as 0 to 20% in the high speed and high load ranges. are doing. The reason is as follows.

Ideally, it is desirable to increase φP over the entire range, but if φP is increased at high speeds and high loads, the injected fuel from the premixed fuel injector will be more likely to be inhaled into cylinders other than the designated cylinders, and the air-fuel mixture between the cylinders will be reduced. A problem arises in that the concentration, that is, the air-fuel ratio deviation increases. Furthermore, in high speed and high load ranges, the airflow velocity entering the combustion chamber also increases, which promotes atomization of the fuel airflow near the intake valve. Therefore, in such a high-speed, high-load range, it is possible to reduce the premix ratio φP, reduce the air-fuel ratio deviation between cylinders, and improve the formation of the air-fuel mixture that flows into the combustion chamber by atomizing the airflow. most effective.

Further, in a partial operating range where the engine speed is 1000 to 2000 rpm and the throttle opening is partially open, the air-fuel ratio deviation is not large, so the premix ratio is set to 50 to 60%.

Next, in low speed and light load ranges such as idling, the amount of fuel supplied is small, so the opening time of both premixed fuel injection valves and cylinder-specific fuel injection valves is extremely short. The fuel temperature injection valve uses an electromagnetic type, and due to electrical and mechanical delays, the lift response of the valve to the driving electric pulse signal is accompanied by a delay of several hundred μBeC, or more specifically, 1, for example, 600 μsec. After a dead time of , it responds with a rising edge of 100 μsec. Therefore, in the above-mentioned low speed and light load range, the valve will not open if the valve opening time is within 700 μsec in the above example. Therefore, considering the responsiveness of both the premixing fuel injection valve and the cylinder-specific fuel injection valve, in such areas,
φP is set to about 50%.

As shown in FIG. 4, the premix ratio φP is determined by creating a map in the control device 3 using the ratio Q a /N between the engine speed N and the air amount Qa, that is, the load information.

The premix ratio φP may be read out by map search from the N and Qa signals or the N and load information signals, and the opening times of both the injection valves may be determined and controlled.

Further, as shown in FIG. 3, the valve opening timing phase difference ΔT between the two injection valves 11 and 12 is also determined by N and Q a /
By creating a map with N and reading out ΔT by searching the map using N and Qa times the signal, both the above injection valves 11.12
All you have to do is decide and control the valve opening timing.

According to this embodiment, the amount of fuel corresponding to the required air-fuel ratio is injected separately into the cylinder-specific fuel injection valve 11 and the premix fuel injection valve 12, and the fuel is injected from the premix fuel injection valve 12. Since the degree of uniform formation of the air-fuel mixture increases in terms of time and space, the air-fuel mixture characteristics can be significantly improved.

As a result, even with an electronic multi-point fuel injection system that injects fuel intermittently, it is possible to supply the engine with a mixture that is almost as uniform as a carburetor, resulting in stable combustion in the partial load range. efficiency, lean burn, and exhaust purification.
Fuel consumption can be reduced.

Furthermore, even when accelerating from a low speed, the premixed air-fuel mixture is sent to the engine combustion chamber when increasing the amount of combustion material, so there is no interruption of fuel and transient operation can be performed smoothly.

In addition, depending on the engine operating conditions, the fuel injection valve 1 for each cylinder
Since the PID control is performed to change the ratio of fuel between the premix fuel injection valve 1 and the premix fuel injection valve 12, the response of the engine will not be affected.

In addition to the cylinder-specific fuel injection valve 11, a premixed fuel injection valve 1 is also provided.
By using 2 together, it becomes easier to control lean burn operation, and as a result, the number of control programs in the control unit is reduced and complicated control algorithms are not required (conventional programs during transients such as acceleration and deceleration are (complicated) etc. Note that the premixing in this example applies to partial load, low speed and low load,
In addition to various high-speed, high-load operations, it can also be used to increase fuel for low-temperature starts.

〔Effect of the invention〕

As described above, according to the present invention, the cylinder-specific fuel injection valve and the premix fuel injection valve share the fuel amount corresponding to the required air-fuel ratio during partial load operation, etc. based on the set ratio, so that the air-fuel mixture By improving the mixing characteristics, an electronic multi-point fuel injection system can supply an engine with a temporally and spatially uniform air-fuel mixture to the same extent as a carburetor. therefore,
Along with this, the stability of combustion will improve and lean burn will be achieved.

Purifies exhaust gas and reduces fuel consumption. Furthermore, transient operating characteristics such as acceleration can also be improved.

[Brief explanation of the drawing]

1 and 2 are system configuration diagrams showing one embodiment of the present invention, FIG. 3 is a time chart showing the operation of the cylinder-specific fuel injection valve and the premix fuel injection valve used in the above embodiment, and FIG. The figure is an explanatory diagram showing the premix ratio map characteristics of the above embodiment, and FIG. 5 is a flowchart for explaining the operation of the above embodiment. 3...Fuel injection control means (control unit), 11...
・Cylinder-specific fuel injection valve, 12...Premixed fuel injection valve, 1
3... Cylinder, 15... Manifold, 16... Intake passage. Figure 1 11, Negative front PJll guard 1 square tower 2 days 1 also 1 - 咀空通＊3 Figure Pr between father-in-law

Claims (1)

[Scope of Claims] 1. A device for supplying injected fuel to an engine using a fuel injection valve, which has cylinder-specific fuel injection valves disposed for each cylinder of a multi-cylinder engine, wherein these cylinder-specific fuel A premixed fuel injection valve that is common to all cylinders and forms an air-fuel mixture in advance is provided at the installation position of the injection valve and in the intake passage upstream of the intake manifold, and this premixed fuel injection valve is used when the engine is at least in a partial load operating range. Sometimes used in combination with the cylinder-specific fuel injection valve, the fuel amount corresponding to the required air-fuel ratio of the engine is shared between the cylinder-specific fuel injection valve and the premix fuel injection valve based on a set ratio. fuel supply method. 2. In the first aspect, the sharing ratio of the amount of fuel injected by the cylinder-specific fuel injection valve and the premix fuel injection valve is:
A fuel supply method that is set to change depending on the engine operating status. 3. In a device that supplies injected fuel to an engine using fuel injection valves, the cylinder-specific fuel injection valves arranged for each cylinder of a multi-cylinder engine, the installation positions of these cylinder-specific fuel injection valves, and the intake manifold. A premixed fuel injection valve that is common to each cylinder and is arranged in the upstream intake passage and forms a mixture in advance upstream of the intake manifold; and a fuel amount that is measured and injected by the cylinder-specific fuel injection valve. and control means for changing the ratio of the amount of fuel metered and injected by the premix fuel injection valve in accordance with engine operating conditions such as speed and load, and the control means is configured to control the fuel injection valve for each cylinder. and introducing proportional, integral, and differential elements as a control method for the premixed fuel injection valve, and setting constants of these control elements to be different between the cylinder-specific fuel injection valve and the premixed fuel injection valve. A fuel supply device featuring: