JPH07197831A - Engine fuel controller - Google Patents

Abstract

(57) [Abstract] [Purpose] In accordance with the introduction amount of EGR gas supplied from the EGR supply means to the cylinder, the EUT correction amount is increased so that the fuel supply amount increases as the EGR introduction amount increases. By doing so, it is possible to appropriately correct the fluctuation of the wet amount due to the change of the intake port flow velocity due to the change of the EGR ratio, and it is possible to supply the fuel corresponding to the required amount of fuel into the cylinder, The occurrence of a so-called lean spike in which the air-fuel ratio temporarily becomes lean is prevented. A fuel control device for an engine, comprising an EGR supply means P3 for supplying EGR gas into a cylinder while a fuel injection valve P2 is provided in an intake port P1.
The EGR amount changing means P4 for changing the EGR amount in accordance with the operating state of No. 2, and the reading means P6 for reading the EGR introduction amount,
In accordance with the EGR introduction amount read by the reading unit P6, a correction unit P7 for increasing and controlling the wet correction amount is provided so that the fuel supply amount increases as the EGR introduction amount increases. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, for example, has a primary intake port and a secondary intake port, and a fuel injection valve is arranged in the primary intake port, while an EGR inlet is provided in the secondary intake port. The present invention relates to an engine fuel control device.

[0002]

2. Description of the Related Art Conventionally, as a control device for an engine, for example, as described in Japanese Patent Laid-Open No. 64-104920,
There is a device having a primary intake port and a secondary intake port, and a swirl control valve so-called SCV is provided in the above-mentioned secondary intake port.

On the other hand, as a fuel control device for an engine,
For example, as described in Japanese Patent Publication No. 3-59255, the amount of fuel adhering to the wall surface of the intake pipe (wet amount) is increased, and the amount of fuel taken away in the combustion chamber is decremented. There is a device that corrects the fuel amount actually supplied to the combustion chamber of the engine by correcting the fuel injection amount (so-called in-maniwet correction) so as to correspond to a predetermined preferable air-fuel ratio.

Therefore, when these two prior arts are combined, an intake two-valve independent intake structure having a primary intake port and a secondary intake port is provided, and the above-mentioned secondary intake port is provided with a swirl control valve and the swirl control valve A fuel control device for an engine that executes in-maniwet correction according to opening / closing is configured, and proper fuel correction corresponding to opening / closing of the swirl control valve can be executed.

However, when the secondary intake port is provided with an EGR introduction port for the purpose of improving fuel consumption by reducing NOx and pumping loss, the following problems occur in the above-mentioned combined configuration.

That is, from the secondary intake pate to EG
When R gas is introduced into the cylinder, the internal pressure of the cylinder increases, the differential pressure between the cylinder and the primary intake port decreases, and the flow velocity of the intake air flowing through the primary intake port decreases, so As the flow velocity becomes slower, the carry-off amount decreases, the amount of fuel supplied into the cylinder does not match the required amount, and the air-fuel ratio becomes lean.

The flow velocity of the primary intake port is EG
When the swirl control valve is closed, the absolute value of the primary intake port flow velocity becomes large compared to when the swirl control valve is open. It will become more prominent.

[0008]

The invention according to claim 1 of the present invention is an EG supplied from the EGR supply means into the cylinder.
In accordance with the amount of introduced R gas, the wet correction amount is controlled to increase so that the fuel supply amount increases as the EGR introduced amount increases, so that the wet amount changes due to the intake port flow velocity change due to the EGR ratio change. It is possible to properly correct the fluctuation, supply the fuel corresponding to the required amount of fuel into the cylinder, and prevent the occurrence of a so-called lean spike in which the air-fuel ratio temporarily becomes lean. An object of the present invention is to provide a fuel control device for an engine.

According to the second aspect of the present invention, the fuel supply amount increases as the EGR introduction amount increases, corresponding to the EGR gas introduction amount introduced from the EGR introduction port of the secondary intake port. By increasing the wet correction amount, it is possible to appropriately correct the fluctuation of the wet amount due to the change of the flow velocity of the primary intake port (the intake port on the side where the fuel injection valve is arranged) due to the change of the EGR ratio. A fuel control device for an engine capable of supplying a fuel corresponding to a required amount of fuel into a cylinder and preventing occurrence of a so-called lean spike in which the air-fuel ratio temporarily becomes lean. And

According to the third aspect of the present invention, when the swirl control valve provided in the secondary intake port is closed, the absolute value of the flow velocity of the primary intake port becomes larger than that when the valve is opened, and the primary intake air is introduced by EGR. Since the change in the flow velocity of the intake port becomes large, by executing the wet correction amount increasing control when the swirl control valve is closed, it is possible to more appropriately correct the change in the wet amount due to the change in the EGR ratio. For the purpose of providing.

[0011]

According to a first aspect of the present invention, the fuel control of the engine is provided with the EGR supply means for supplying the EGR gas into the cylinder while the fuel injection valve is provided in the intake port. An EGR amount changing means for changing the EGR amount according to the operating state of the engine;
Reading means for reading the introduction amount, and correction means for increasing and controlling the wet correction amount so that the fuel supply amount increases as the EGR introduction amount increases corresponding to the EGR introduction amount read by the reading means. It is a fuel control device for an engine provided with.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, the intake port includes a primary intake port and a secondary intake port having an independent intake configuration, and the fuel injection valve Is arranged in the primary intake port, while the EGR inlet is formed in the secondary intake port.

According to a third aspect of the present invention, in addition to the configuration of the second aspect of the invention, a swirl control valve is provided in the secondary intake port, and the EGR is performed.
The fuel control device for an engine is characterized in that the introduction port is formed on the downstream side of the swirl control valve and the above control is executed when the swirl control valve is closed.

[0014]

According to the invention described in claim 1 of the present invention, as shown in the claim correspondence diagram of FIG. 7, while the intake port P1 and the fuel injection valve P2 are arranged, the above-mentioned cylinder is provided. In the engine fuel control device including the EGR supply means P3 for supplying the EGR gas, the above-mentioned EGR amount changing means P4 changes the EGR amount according to the operating state of the engine P5, and the above-mentioned reading means P6 is the EGR. The introduction amount is read, and the correction unit P7 corresponds to the EGR introduction amount (EGR ratio) read by the reading unit P6 described above,
The wet correction amount is increased and controlled so that the fuel supply amount from the fuel injection valve P2 increases as the introduction amount increases.

That is, when the EGR gas is introduced, the cylinder internal pressure increases, the differential pressure between the cylinder and the intake port P1 decreases, the port flow velocity decreases, and the amount of fuel supplied into the cylinder increases. Has a tendency to decrease with respect to the required amount, so the above-mentioned wet correction amount is controlled to increase so as to correct this.

As a result, it is possible to properly correct the fluctuation of the wet amount due to the change of the intake port flow velocity due to the change of the EGR ratio, and it is possible to supply the fuel corresponding to the required amount of fuel into the cylinder. As a result, the so-called lean spike in which the air-fuel ratio temporarily becomes lean can be prevented.

According to the second aspect of the present invention, the EG introduced from the EGR inlet of the secondary intake port
With respect to the amount of R gas introduced, the correction means controls the wet correction amount so that the fuel supply amount increases as the EGR introduction amount increases, so the primary intake port (fuel injection valve (Intake port on the installed side) It is possible to properly correct the fluctuation of the wet amount due to the change of the flow velocity, and to supply the fuel corresponding to the required amount of fuel into the cylinder. It is possible to prevent the so-called lean spike in which the fuel ratio temporarily becomes lean.

According to the invention of claim 3 of the present invention,
When the swirl control valve provided in the secondary intake port is closed, the absolute value of the flow velocity of the primary intake port becomes larger than when it is opened, and the flow velocity change of the primary intake port due to the introduction of EGR (in other words, the amount of intake pipe wall adhesion The fluctuation of the wet amount due to the change of the primary intake port flow rate due to the change of the EGR ratio is executed by executing the above-described increase control of the wet correction amount when the swirl control valve is closed. Can be appropriately corrected, fuel corresponding to the required amount of fuel can be supplied into the cylinder, and the so-called lean spike in which the air-fuel ratio temporarily becomes lean is further significantly prevented. There is an effect that can be.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows a fuel control system for an engine. In FIG. 1, a cylinder head of an in-line four-cylinder engine 1 communicates with each fuel chamber 2 by opening / closing an intake / exhaust valve.
Two intake ports 3P and 3S and two exhaust ports 4 and 4 are formed per cylinder.

Of the two intake ports 3P, 3S formed in the intake two-valve independent intake structure, the primary intake ports 3P ... Of the surge tank 5 are connected to the primary intake ports 3P. Similarly, the respective secondary side intake manifolds 6S downstream of the surge tank 5 are connected to the respective secondary intake ports 3S.

An injector 7 as a fuel injection valve is provided in each of the above primary intake ports 3P, while a swirl control valve (so-called SCV) 8 is provided in each of the above secondary side intake manifolds 6S. However, EGR inlets 9 ... Are formed on the downstream side of each of the swirl control valves 8.

Here, the above-mentioned EGR inlet 9 ...
A throttle valve 12 is provided in the intake passage 11 upstream of the surge tank 5 while being connected to a predetermined portion of the exhaust system of the engine 1 via the passage 10.

FIG. 2 shows a control circuit of the engine fuel control device. The CPU 20 has an engine speed Ne from the distributor 13, an intake air amount Q from the air flow sensor 14, and a water temperature tw of the engine cooling water from the water temperature sensor 15.
Based on various necessary signal inputs such as the following, the injector 7 and the swirl control valve 8 actuator 17 for opening and closing are driven and controlled in accordance with a program stored in the ROM 16, and the RAM 18 is used for the EGR target ratio map M1 shown in FIG. Also, necessary maps and data such as the maps (MapB) and (MapA) of the correction amounts shown in FIGS. 4 and 5 are stored. The open / close signal of the swirl control valve 8 is fed back to the CPU 20.

Here, in the above-mentioned EGR target ratio map M1 (see FIG. 3), the horizontal axis represents the engine speed Ne,
The load CE (however, CE = Q / Ne) is taken on the vertical axis, and the EGR target ratio is 0% corresponding to the engine operating conditions.
The map is divided into 5%, 10%, and 20%. In addition, the above-mentioned CPU 20 is a steady EGR target ratio 2
Even in the 0% range, the EGR target ratio is changed to 10% or less during acceleration or transition.

Further, the above correction amount map (MapB)
(See FIG. 4) is a normal wet correction amount map in which the horizontal axis represents the engine speed Ne and the vertical axis represents the load CE, and the values of the wet correction amount are divided into large, medium, and small values.

Further, the above-mentioned correction amount map (MapA)
(See FIG. 5) is a map of the amount of wet correction corresponding to the EGR target ratio in which the value of the amount of wet correction is divided into large, medium and small by taking the engine speed Ne on the horizontal axis and the load CE on the vertical axis. is there.

On the other hand, the CPU 20 described above has a determination means for determining whether or not the swirl control valve 8 is closed (refer to the first step S1 in the flowchart shown in FIG. 6) and the current E.
Corresponding to the reading means for reading the GR introduction amount (see the fifth step S5 of the flowchart shown in FIG. 6) and the EGR introduction amount read by the above-mentioned reading means, the larger the EGR introduction amount, the more the EGR introduction amount from the injector 7 Correction means for increasing and controlling the wet correction amount so that the fuel injection amount increases (see FIG. 6).
(See the sixth step S6 of the flowchart shown in FIG. 4).

In this embodiment, when the swirl control valve 8 is closed, the wet correction amount increasing control corresponding to the EGR introduction amount is executed.

The operation of the engine fuel control device thus constructed will be described in detail below with reference to the flow chart shown in FIG.

In the first step S1, the CPU 20 determines whether or not the swirl control valve 8 is closed. When the swirl control valve 8 is open (heavy EGR is in the load region), the process proceeds to the next second step S2. .

In the above-mentioned second step S2, the CPU 20 executes the reading of the engine speed Ne from the distributor 13 and the intake air amount Q from the air flow sensor 14, and at the same time the load is calculated based on the arithmetic expression CE = Q / Ne. Calculate CE.

Next, in a third step S3, the CPU 20 next calculates a normal wet correction amount based on the calculation formula shown in [Equation 1].

Here, the correction amount MapB (N
e, CE) are values read from the map (MapB) shown in FIG.

Next, in a fourth step S4, the CPU 20 changes the fuel correction amount in accordance with the normal wet correction amount described above, and then at a predetermined fuel injection timing, the injector 7 according to the changed fuel correction amount. To drive.

On the other hand, when it is determined that the swirl control valve 8 is closed in the above-mentioned first step S1 (region where heavy EGR is possible due to generation of swirl), the process proceeds to another fifth step S5.

In the above-described fifth step S5, the CPU 20 reads the engine speed Ne from the distributor 13 and the intake air amount Q from the air flow sensor 14, and at the same time, loads the load based on the arithmetic expression CE = Q / Ne. CE is calculated, and the current EG is calculated from the map M1 in FIG.
Read the R target ratio.

Next, in a sixth step S6, the CPU 20 next calculates the wet correction amount corresponding to the EGR target ratio based on the arithmetic expression shown in [Equation 2].

Here, the correction amount MapA (N
e, CE) are values read from the map (MapA) shown in FIG.

In the above-mentioned [Equation 2], the P-port flow velocity substitution function fv relating to the EGR amount has such a value that the wet correction amount is controlled to increase as the EGR introduction amount increases.

Then, the process proceeds to the fourth step S4, where the fourth
In step S4, the CPU 20 changes the fuel correction amount according to the wet correction amount corresponding to the EGR target ratio, and then drives the injector 7 according to the changed fuel correction amount at a predetermined fuel injection timing.

In summary, the EGR amount changing means (see the EGR target ratio map M1 in FIG. 3) changes the EGR amount in accordance with the operating state of the engine 1, and the reading means (see fifth step S5) described above. The EGR introduction amount is read, and the correction unit (see the sixth step S6) corresponds to the EGR introduction amount (EGR ratio) read by the reading unit, and the fuel injection amount from the injector 7 increases as the EGR introduction amount increases. The wet correction amount is controlled to increase so as to increase.

That is, when the EGR gas is introduced, the cylinder internal pressure increases, and the cylinder interior and the primary intake port 3P
Since the pressure difference between and decreases, the port flow velocity decreases, and the amount of fuel supplied to the cylinder tends to decrease with respect to the required amount. Therefore, the above-mentioned wet correction amount is increased to correct this. To do.

As a result, it is possible to properly correct the fluctuation of the wet amount due to the change of the flow velocity of the primary intake port 3P due to the change of the EGR ratio, and to supply the fuel corresponding to the required amount of fuel into the cylinder. Therefore, it is possible to prevent the so-called lean spike in which the air-fuel ratio temporarily becomes lean.

Further, the above-mentioned secondary intake port 3S
Side, more specifically, when the swirl control valve 8 provided on the secondary side intake manifold 6S is closed,
Since the absolute value of the flow velocity of the primary intake port 3P becomes larger than that when is open, the flow velocity change of the primary intake port 3P due to the introduction of EGR (in other words, the variation of the wet amount as the intake pipe wall surface attachment amount) becomes large. By executing the above-described increase control of the wet correction amount when the swirl control valve 8 is closed, it is possible to appropriately correct the fluctuation of the wet amount due to the flow velocity change of the primary intake port 3P due to the EGR ratio change. Therefore, the fuel corresponding to the required amount of fuel can be supplied into the cylinder, and the so-called lean spike in which the air-fuel ratio temporarily becomes lean can be prevented more significantly.

In the correspondence between the configuration of the present invention and the above-described embodiment, the fuel injection valve of the present invention corresponds to the injector 7 of the embodiment, and similarly, the EGR supply means is the EG.
Corresponding to the R inlet 9, the EGR amount changing means corresponds to the EGR target ratio map M1 shown in FIG. 3, and the reading means corresponds to the fifth step S5 under the control of the CPU 20,
The correction means corresponds to the sixth step S6 controlled by the CPU 20, but the present invention is not limited to the configuration of the above-described embodiment.

For example, in the above embodiment, the wet correction amount corresponding to the EGR target ratio is calculated by using the P port flow velocity substitution function fv.
The wet correction amounts corresponding to the R ratios of 20%, 15%, 8%, and 0% may be stored in advance in another map (not shown), and the wet correction amounts may be read from this map. Good.

[Brief description of drawings]

FIG. 1 is a system diagram showing a fuel control device for an engine of the present invention.

FIG. 2 is a block diagram of a control circuit.

FIG. 3 is an explanatory diagram of a map showing an EGR target ratio.

FIG. 4 is an explanatory diagram of a map showing a normal wet correction amount.

FIG. 5 is an explanatory diagram of a map showing a wet correction amount corresponding to an EGR target ratio.

FIG. 6 is a flowchart showing in-maniwet correction processing.

FIG. 7 is a claim correspondence diagram.

[Explanation of symbols]

 3P ... Primary intake port 3S ... Secondary intake port 7 ... Injector 8 ... Swirl control valve 9 ... EGR introduction port M1 ... EGR amount changing means S5 ... Reading means S6 ... Correction means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F02D 43/00 301 H N F02M 25/07 550 G 69/00 360 AC (72) Inventor Nakao Yuji 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (3)

[Claims] 1. A fuel injection valve is installed in an intake port,
A fuel control device for an engine, comprising an EGR supply means for supplying EGR gas into a cylinder, comprising: an EGR quantity changing means for varying the EGR quantity according to an operating state of the engine;
Corresponding to the EGR introduction amount read by the reading unit and the EGR introduction amount read by the reading unit, the correction unit for increasing and controlling the wet correction amount so that the fuel supply amount increases as the EGR introduction amount increases. And a fuel control device for the engine. 2. The intake port includes a primary intake port and a secondary intake port having an independent intake structure, and the fuel injection valve is arranged in the primary intake port while the EG is provided.
The engine fuel control device according to claim 1, wherein the R inlet is formed in the secondary intake port. 3. A swirl control valve is provided in the secondary intake port, the EGR inlet is formed downstream of the swirl control valve, and the control is executed when the swirl control valve is closed. Engine fuel control system.