JP3095085B2 - Engine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control apparatus having a combustion speed improving means for improving a combustion speed.

[0002]

2. Description of the Related Art Conventionally, the following two means are generally known as means for improving the combustion speed. In other words, a primary passage which gives a circumferential swirl in the combustion chamber to the air-fuel mixture supplied to the combustion chamber is provided, and a secondary passage is provided to improve the mixing of fuel and air by generating the above-described swirl. A dual injection system (so-called DIS) for improving the combustion speed, and an assist air supply means for supplying assist air (auxiliary air) near the injection port of the injector to atomize the fuel and improve the combustion speed. There are two.

As an engine provided with the above assist air supply means, there is, for example, an engine described in Japanese Utility Model Laid-Open Publication No. 2-46071. That is, an assist air supply passage that bypasses the throttle valve is provided, and the tip of the assist air supply passage is opened near the injection port of the injector,
The engine is configured to supply assist air by utilizing a pressure difference between a pressure upstream of the throttle valve and a pressure downstream of the throttle valve.

The conventional engine having the assist air supply means has the following problems. In other words, when traveling at high altitude where the atmospheric pressure is low, or when carbon adheres to the assist air supply passage due to deterioration over time, the assist air amount becomes insufficient with respect to the required assist air amount. As a result, the combustion speed is reduced due to the deterioration of the mixing of the fuel and the air, and the sufficient combustion of the air-fuel mixture in the combustion chamber is hindered. There was a problem that thermal deterioration of the tube and the catalytic converter became large.

[0005] This is not limited to the above-described assist air supply means, but also applies to a dual injection system. In the case of a failure of a diaphragm for boost-controlling the on-off valve provided in the above-mentioned secondary passage, the on-off valve may be used. When the closing control is stopped, it is difficult to generate the swirl by the primary passage, so that there is a problem that the combustion speed is reduced and the exhaust system temperature is increased.

[0006]

According to the first aspect of the present invention, the engine speed is equal to or less than a set speed, and
In the first air-fuel ratio setting area where the engine load is equal to or less than the set load,
When the air ratio of the air-fuel mixture supplied to the engine is
And set the engine speed to the above
Or the engine load is higher than the set load
Is higher than the second air ratio setting range,
The air-fuel ratio of the air-fuel mixture is richer than the first air-fuel ratio.
Set the second air-fuel ratio to suppress exhaust system temperature rise
Oite sometimes fail (fail) burn rate enhancing means, the
2 Fuel cooling by expanding the air-fuel ratio setting area
Accordingly , it is an object of the present invention to provide an engine control device capable of reliably preventing the exhaust system temperature from rising.

[0007] The invention of claim 2, wherein the present invention is the請
In addition to the object of the invention described in claim 1, it is also possible to enlarge the second air-fuel ratio setting area when the assist air supply means fails.
Accordingly , an object of the present invention is to provide an engine control device capable of reliably preventing the combustion speed from decreasing due to the shortage of the assist air amount and increasing the exhaust system temperature.

[0008] The invention described in claim 3 of the present invention is characterized in that :
In addition to the object of the invention described in claim 1, the swirl generating means
By expanding the second air-fuel ratio setting area in the event of malfunction,
Therefore, it is an object of the present invention to provide an engine control device capable of cooling the fuel and reliably preventing the exhaust system temperature from rising .

[0009]

According to the first aspect of the present invention, the engine speed is equal to or less than a set speed and the engine speed is set to a predetermined value.
When the engine load is in the first air-fuel ratio setting area below the set load,
Empty Shikahi of mixed Aiki supplied to engine to the first set air Shikahi
Set the engine speed so that the engine speed is
High or the engine load is higher than the set load
Air-fuel mixture supplied to the engine in the second air-fuel ratio setting area
The second air-fuel ratio, which is richer than the first set air-fuel ratio
Engine control to control exhaust system temperature rise by setting ratio
In the device, the fuel speed to increase the combustion speed in the combustion chamber
Degree improving means, fail detecting means for detecting a failure of the combustion speed improving means, and changing the set number of revolutions to a low rotation side when the fail detecting means detects a failure , or
Change the set load to the low load side to expand the 2nd air ratio setting area
The engine control device further comprises a second air- fuel ratio area enlarging means .

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the combustion speed improving means is constituted by assist air supply means for supplying assist air to the vicinity of the injection port of the injector. Further, the present invention is characterized in that the control device is an engine control device that activates the second air- fuel ratio setting area expanding means when the assist air is insufficient.

[0011] The invention of claim 3, wherein the present invention, in conjunction with the configuration of the invention according to the first aspect, is supplied to the fuel chamber
The swirl generating means that gives swirl to the mixture
It constitutes a means for improving the combustion speed, and the operation of the swirl generating means does not work.
An engine control device that activates the second air-fuel ratio setting area enlarging means in a good condition .

[0012]

According to the first aspect of the present invention, the engine speed is equal to or less than the set speed and the engine
When the load is in the first air-fuel ratio setting area below the set load, the engine
The air-fuel ratio of the mixture supplied to the engine to the first set air-fuel ratio
And the engine speed is higher than the above set speed.
Or the engine load is higher than the set load
2 When the air-fuel ratio is set, the air-fuel mixture supplied to the engine
The second air ratio that is richer than the first set air ratio in the air ratio
To suppress exhaust system temperature rise by setting
The above-mentioned means for improving the combustion speed improve the combustion speed in the combustion chamber.
However, the fail detecting means detects a defect in the fuel speed improving means.
When the second air- fuel ratio area is expanded,
Enlarge the setting area. In other words, set the number of revolutions
Change or set load to lower load area
To enlarge.

As a result, the fuel is cooled and the exhaust system temperature is reduced.
The exhaust pipe and catalyst converter can be reliably prevented from rising.
This has the effect of reducing thermal degradation of the data.

According to the second aspect of the present invention,
In addition to the effect of the first aspect of the present invention, the assist air supply means may fail and the assist air may be insufficient.
When this condition is reached , the failure detection means detects this state, and the second air-fuel ratio setting area expanding means described above outputs the second air-fuel ratio setting area.
Is expanded as described above, so that there is an effect that the fuel can be cooled, the temperature of the exhaust system can be reliably prevented from rising, and the thermal deterioration of the exhaust pipe and the catalytic converter can be reduced.

According to the third aspect of the present invention,
In addition to the effect of the first aspect of the present invention, swirl generation
In the event of a device malfunction (failure), this
Detecting means for detecting and increasing the above-mentioned second air-fuel ratio setting area expanding means;
Expands the second air-fuel ratio setting area as described above,
To prevent the temperature of the exhaust system from rising,
Thermal degradation of exhaust pipes and catalytic converters can be reduced.
There is a clear effect.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawing shows an engine control device. In FIG. 1, an air flow meter 2 is connected to a purified air outlet of an air cleaner 1.
The throttle body 3 is connected to the downstream side of the air flow meter 2, and a throttle valve 5 is disposed in a throttle chamber 4 of the throttle body 3.

A surge tank 6 is connected to the throttle chamber 4 downstream of the throttle valve 5. A plurality of outlets of the surge tank 6 are connected to one bank 8 and the other bank via intake manifolds 7, 7. Each intake port 10 of the bank 9 is connected.

The above-described one-side bank 8 of the V-type engine 11
And each exhaust port 1 in the other bank 9
Exhaust manifolds 13 and 13 are connected to the exhaust manifolds 2 and 12, respectively, and a catalytic converter 15 is provided in an exhaust passage 14 downstream of the gathering portion of the exhaust manifolds 13 and 13.

The exhaust manifolds 13 and 13 near the exhaust ports 12 and 12 are provided with O2 sensors 16 and 16 as an air-fuel ratio sensor, while controlling the water temperature in a water jacket formed on the outer periphery of a cylinder block 17. An engine coolant temperature sensor 18 for detecting a temperature of the engine and a crank angle sensor 19 for detecting a crank angle are provided, and injectors 20, 20 are provided in the above-described intake ports 10, 10, respectively.

The intake system of the above-described V-type engine 11 is provided with assist air supply devices 21 and 21 as an example of a combustion speed improving means for improving the combustion speed in the combustion chamber . This assist air supply device 21 has one end opened to the throttle chamber 4 upstream of the throttle valve 5 and the other end opened to the vicinity of the injection port of the injector 20 to supply assist air by effectively utilizing the differential pressure. an air supply passage 22, provided in the middle portion of the assist air supply passage 22, and a Dew <br/> Te I solenoid valve 23 for adjusting the supply amount of the assist air.

The above-mentioned duty solenoid valve 23
A pressure is detected in the assist air supply passage 22 on the downstream side of the
The pressure sensor 24 is provided as a fail detecting means for checking the failure of the sensor.

Here, the duty solenoid valve 23 supplies assist air when the duty ratio D is set to a predetermined value Dset, and when the duty ratio D = 0,
The supply of the assist air is stopped.

FIG. 2 shows a control circuit of the engine control device. The CPU 30 includes an engine speed Ne from the distributor 25, an intake air amount Q from the air flow meter 2, a fail detection signal from the pressure sensor 24, an O2 sensor 16 Based on the actual air-fuel ratio signal from the throttle sensor, the throttle opening TVO from the throttle sensor 26, and the brake signal from the brake switch 27, the drive of the injector 20 and the duty solenoid valve 23 is controlled in accordance with the program stored in the ROM 28, and the RAM 29 Stores necessary data such as the first map shown in FIG. 4, the second map shown in FIG. 6, and the third map shown in FIG.

In the first map (see FIG. 4), the horizontal axis indicates the engine speed Ne, the vertical axis indicates the load CE, and the light load area A including the idle area and the high load area B.
When the assist air is supplied in the idle region, the engine speed does not converge to the idle target speed due to the excessive intake air amount. Therefore, the supply of the assist air is restricted or prohibited in the idle region. It is a map for.

In the second map (see FIG. 6), the horizontal axis represents the engine speed Ne and the vertical axis represents the engine load CE.
And a feedback zone (the first air- fuel ratio) that corrects the fuel injection amount based on the deviation between the target air-fuel ratio and the actual air-fuel ratio in the low-speed low-load region so that the air-fuel ratio becomes the stoichiometric air-fuel ratio.
And the high-load fuel increase zone (the second air- fuel ratio setting area).
(A constant area) .

That is, the engine speed Ne is equal to the set speed.
And the first air-fuel whose engine load CE is equal to or less than the set load.
When in the ratio setting area (see F / B zone),
When the air ratio of the supplied mixture is set to the first set air ratio
In both cases, the engine speed Ne is higher than the set speed.
Or, if the engine load CE is higher than the set load
2 In the air-fuel ratio setting area (see the high-load fuel increase zone),
The air-fuel ratio supplied to the engine 11 is set to the above-described first ratio.
Exhaust system temperature by setting the second air ratio richer than the air ratio
This is for suppressing the rise.

In the third map (see FIG. 7), the horizontal axis represents the engine speed Ne, and the vertical axis represents the engine load C.
E is a map in which the feedback zone (the first air- fuel ratio setting area) is set narrower and the high-load fuel increase zone (the second air- fuel ratio setting area) is set wider than the second map. The boundary line a of each zone in the second map (see FIG. 6) becomes like a dotted line in the third map (see FIG. 7).

On the other hand, when the assist air amount by the assist air supply device 21 becomes insufficient with respect to the requested assist air amount due to high altitude traveling of the vehicle or deterioration with time, the CPU 30 at least increases the load. In a region (specifically, in a region other than the feedback zone described above), a correction unit (refer to an eighth step 58 in the flowchart of FIG. 5) that corrects the fuel from the injector 20 in the increasing direction, and when the assist air supply device 21 fails, Expand the high load fuel increase area to the low load side (
Change the number of turns to the low rotation side or set the above load to the low load side
To enlarge the second air-fuel ratio setting area) (see fourth step 54 in the flowchart of FIG. 5).

The operation of the engine control device configured as described above will be described with reference to the flowcharts of FIGS.

First, the supply control of the assist air will be described with reference to the flowchart of FIG. 3. In a first step 31, the CPU 30 determines the engine speed Ne from the distributor 25, the intake air amount Q from the air flow meter 2, and the like. Various necessary signals are read, and in the next second step 32, the CPU 30 calculates the load CE based on the equation of CE = Q / Ne, and also calculates the load CE based on the engine speed Ne and the load CE described above. To determine whether or not the vehicle is in the idle zone (whether or not the vehicle is in the area A of the first map shown in FIG.
In the case of the region A, the process proceeds to the next third step 33, and in the case of the region B, the process proceeds to another fourth step 34.

In the fourth step 34, the CPU 30 sets the duty ratio D of the duty solenoid valve 23 to a predetermined value D.
After setting to set, the process proceeds to the next fifth step 35, in which the CPU 30 drives the duty solenoid valve 23 with the duty ratio D = Dset, and supplies the assist air corresponding to the high load region B. It is supplied near the injection port of the injector 20.

On the other hand, in the above-mentioned third step 33, the CPU
30 is a step for judging whether or not it is the previous off-idle, and at the time of deceleration determined to be the last off-idle, the next sixth step 36
On the other hand, when the idle state is determined not to be the idle state last time, the processing shifts to another seventh step 37.

In the above-described sixth step 36, the CPU 30 determines whether or not the brake is ON (braking) based on the output from the brake switch 27. inertia run line
Do etc. to determine by slow deceleration, during slow deceleration the program shifts to the eighth step 38 follows, at the time of rapid deceleration to migrate to another ninth step 39.

In the above-described eighth step 38, the CPU 30 sets the duty ratio D of the duty solenoid valve 23 to zero, and immediately stops the supply of the assist air in response to the slow deceleration.

On the other hand, in the ninth step 39, the CPU
30 sets the flag (F = 1), and then sets the next first
0 In step 10, the process proceeds to step 10.
The CPU 30 determines whether the duty ratio D is zero. At the time of rapid deceleration that has shifted from off-idle to idle, since D = Dset in the previous fourth step 34, in this case (NO determination), the following eleventh step 4
In this eleventh step 41, the CPU 30 decrements the duty ratio D, that is, D = Dset−
ΔD is executed, and the process of attenuating the duty ratio D is performed in the above-described steps 31, 32, 33, 37, 40, 41, and 35.
Is executed until D ≦ 0. That is, at the time of rapid deceleration that has shifted from off-idle to idle by brake operation, the supply amount of assist air is gradually reduced by tailing processing of the duty ratio D to prevent engine stall (stall).

When it is determined in the above-described tenth step 40 that D ≦ 0 (when YES is determined), the following twelfth step is performed.
The process proceeds to step 42, and in this twelfth step 42, C
After resetting the flag (F = 0), the PU 30 proceeds to the eighth step 38 described above.

On the other hand, in the above-mentioned seventh step 37, the CPU
30 determines whether or not F = 1, and when F = 1, the process proceeds to the tenth step 40, and when F = 0, the thirteenth step 4
The CPU 30 sets the duty ratio D to zero in the thirteenth step 43.

In short, the flowchart of FIG. 3 shows that the duty ratio D = Dset at the time of off idling corresponding to the region B.
To drive the detent solenoid valve 23 to supply a predetermined amount of assist air to the vicinity of the injection port of the injector 20,
If the transition from off-idle to idle is slow deceleration due to coasting or the like, the supply of assist air is immediately stopped.If the transition from off-idle to idle is rapid deceleration due to brake operation, assist air Is gradually reduced to prevent engine stall (stall).

Next, the fuel increase control as an example of the exhaust system temperature rise prevention control will be described with reference to the flowchart of FIG. Note that the flowchart of FIG. 5 is processed in parallel with the flowchart of FIG.

In a first step 51, the CPU 30 reads necessary signals such as the engine speed Ne and the intake air amount Q. In a second step 52, the CPU 30 executes Tp = (Q / Ne) × The basic injection amount Tp is calculated according to the calculation formula of K. Note that K in the above equation is a constant.

Next, in a third step 53, the CPU 30 determines whether or not it is an assist air fail based on the input from the pressure sensor 24. The pressure sensor 24 outputs a fail signal because the pressure in the assist air supply passage 22 is reduced when carbon is adhered to the assist air supply passage 22 over time or when traveling on high altitude where the air pressure is low.

If it is determined in the above-described third step 53 that an assist air failure has occurred, the process proceeds to the next fourth step 54, whereas if the assist air is normal, the process proceeds to another fifth step 55.

In the above-described fifth step 55, the CPU 30 executes the reference zone setting. That is, the setting using the second map shown in FIG.
Then, the CPU 30 executes the zone enlargement setting. That is, the setting using the third map shown in FIG. 7 is performed to expand the high-load fuel increase zone toward the low-load side with respect to the reference zone setting.

Next, in a sixth step 56, the CPU 30
The load CE is calculated based on the equation of E = Q / Ne, and it is determined from both the load CE and the engine speed Ne whether the current engine operation state is a feedback zone or a high load fuel increase zone. When the feedback zone is determined, the process proceeds to the next seventh step 57,
When the high load fuel increase zone is determined, another eighth step 58 is performed.
Move to

In the seventh step 57, the CPU 30 corrects the injection amount based on the difference between the target air-fuel ratio and the actual air-fuel ratio read in advance from the O2 sensor 16 so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. The feedback correction amount CFB is calculated to perform the correction to improve the fuel efficiency and to purify the catalytic converter 15, while in the eighth step 58, the CP is calculated.
U30 calculates the high load increase coefficient Cer, and makes a correction to improve the output and to cool the fuel. Here, the above-mentioned high load increase coefficient Cer is set to be larger than that in the normal high load fuel increase zone determination at the time of assist air fail.

Next, in a ninth step 59, the CPU 30 calculates the final injection amount T based on the following equation.

T = Tp × (1 + CFB + Cer) + Tv Here, Tp is a basic injection amount CFB is a feedback correction amount Ce is a high load increase coefficient Tv is an invalid injection amount.

Next, at a tenth step 60, the CPU 30 outputs the result to the injector 20 based on the above-mentioned final injection amount T, executes the fuel injection, and returns to the first step 51.

As described above, when the assist air amount by the assist air supply device 21 becomes insufficient with respect to the required assist air amount, the pressure sensor 2 as a fail detecting means is used.
4 executes fail detection, and based on the fail detection output, the above-described correcting means (see the eighth step 58) corrects the fuel from the injector 20 in the increasing direction in the high load region, so that the fuel is cooled. Therefore, there is an effect that the temperature rise of the exhaust system can be reliably prevented.

In addition, the above-described assist air supply device 21
When the assist air amount is insufficient with respect to the required assist air amount, the pressure sensor 24 performs a fail detection, and based on the detection output, the above-described expanding means (see the fourth step 54) sets the high load fuel. Since the increase range is expanded to the low load side, there is an effect that the fuel can be cooled and the exhaust system temperature can be reliably prevented from rising.

FIG. 8 shows another embodiment of the engine control apparatus. The CPU 70 includes an engine speed Ne from the distributor 25, an intake air amount Q from the air flow meter 2, a fail detection signal from the pressure sensor 24, and a crank angle. Based on the crank angle signal from the sensor 19, the throttle opening TVO from the throttle sensor 26, and the brake signal from the brake switch 27, the duty solenoid valve 23, the igniter coil 63, and the ignition plug 64 are operated according to the program stored in the ROM 61. The drive control is performed, and the RAM 62 stores necessary data such as a map (not shown) of the basic ignition timing IgB corresponding to the engine speed Ne and the load CE.

Here, when the assist air amount provided by the assist air supply device 21 becomes insufficient with respect to the required assist air amount, the CPU 70 performs ignition advance means (see FIG. 9) to advance the ignition timing. (See the fifth step 75 in the flowchart of FIG. 3).

That is, in this embodiment, the assist air supply device 21 is used as the combustion speed improving means, and the ignition timing is advanced as the exhaust system temperature rise preventing means.

The operation of the engine control device thus configured will be described with reference to the flowchart of FIG. Note that the flowchart of FIG. 9 is processed in parallel with the flowchart of FIG. 3 described above.

In a first step 71, the CPU 70 reads various necessary signals such as the engine speed Ne and the intake air amount Q, and then proceeds to the next second step 72.
In this second step 72, the CPU 70 sets CE = Q / Ne
The load CE is calculated on the basis of the above equation, and the basic ignition timing IgB is read from a map (not shown) of the RAM 62 based on the load CE and the engine speed Ne.

Next, in a third step 73, the CPU 70 determines whether or not it is an assist air fail based on the input from the pressure sensor 24. When the vehicle is deteriorated with time or carbon dioxide adheres to the assist air supply passage 22 (see FIG. 1) or when traveling on high altitude where the air pressure is low, the assist air supply passage 2
Since the pressure of No. 2 decreases, the above-described pressure sensor 24 outputs a fail signal.

If it is determined in the third step 73 that the assist air is normal, the process proceeds to the next fourth step 74, while if it is determined that the assist air has failed, the process proceeds to another fifth step 75.

In the above-described fourth step 74, the CPU 70 sets the ignition timing advance correction amount IgA (hereinafter simply referred to as the advance amount) IgA at the time of assist air fail to zero, while in the above-described fifth step 75. The CPU 70 sets the advance angle amount IgA to a predetermined value.

Next, in a sixth step 76, the CPU 70 calculates other correction amounts IgC such as, for example, an acceleration retardation amount and a retardation amount at the time of knocking.
The CPU 70 calculates the final ignition timing Ig based on the following equation.

Ig = IgB + IgA + IgC Here, IgB basic ignition timing IgA is an advance amount IgC is another correction amount.

Next, at an eighth step 78, the CPU 70 sets the igniter coil 63 based on the final ignition timing Ig.
Then, the ignition plug 64 is driven through and the ignition is executed, and the process returns to the first step 71 described above.

As described above, when the assist air amount by the assist air supply device 21 becomes insufficient with respect to the required assist air amount, the above-described pressure sensor 24 performs the fail detection, and based on the fail detection output, Since the ignition advance means (fifth step 75) controls the advance of the ignition timing, the time for which the fuel burns in the combustion chamber becomes longer, and there is an effect that the temperature rise of the exhaust system can be reliably prevented.

FIG. 10 shows another embodiment of the exhaust system temperature rise prevention means. The exhaust system secondary air supply means is used in place of the fuel increase and ignition advance in each of the above-mentioned embodiments to reduce the exhaust system temperature rise. It is configured to prevent it.

That is, the exhaust manifold 1 downstream of the element of the air cleaner 1 and upstream of the catalytic converter 15
3 is connected by a secondary air supply pipe 81,
An air pump 82 is interposed in the next air supply pipe 81 to constitute an exhaust secondary air supply device 83, and the air pump 8 is used at the time of the assist air failure by the pressure sensor 24 described above.
2 is driven to prevent a rise in the temperature of the exhaust system by a large amount of secondary air. Note that the other points are the same as those in FIG.
The same parts are denoted by the same reference numerals and, the detailed description thereof will be omitted.

FIG. 11 shows another embodiment of the combustion speed improving means, in which a dual injection system (so-called D-type) is used in place of the assist air supply means in each of the above-described embodiments.
(IS, intake swirl control) to improve the combustion speed.

That is, between the throttle body 3 and the intake port, a primary passage 84 and a secondary passage 85 as generating means for giving the air-fuel mixture supplied to the combustion chamber a swirl in the circumferential direction in the combustion chamber. Pipe 8 of the dual injection system DIS (swirl generating means) with
In the secondary passage 85 of the intake pipe 86, an on-off valve 88, which is opened and closed by a diaphragm-type actuator 87, is disposed to constitute a DIS 89.

Even if the means for improving the combustion speed by the DIS 89 and the above-mentioned expanding means are combined, it is possible to prevent the temperature of the exhaust system from rising when the DIS 89 fails.
The part exhibits a front view the same features in Figure 11 are denoted by the same reference numerals, and the detailed description thereof will be omitted.

In correspondence between the structure of the present invention and the above-described embodiment, the first air-fuel ratio setting area of the present invention is
Corresponding to the feedback zone (see FIG. 6) , the second air-fuel ratio setting region is similarly set to the high-load fuel increase zone ( see FIG. 6) .
6), the combustion speed improving means is assist air
Supply device (assist air supply means) 21 and DIS (s
( Failure detecting means) 89, and the fail detecting means
Corresponding to the pressure sensor 24 , the second air-fuel ratio area enlarging means includes:
Corresponding to the fourth step 54 (see the flowchart of FIG. 5) controlled by the CPU , the swirl generating means
However , the present invention is not limited to the configuration of the above-described embodiment.

For example, instead of the above-described pressure sensor 24, an air pressure sensor or an altitude sensor composed of a small semiconductor pressure sensing element or an absolute pressure sensor may be used. Further, since the sum Q of the intake air amounts is obtained by the sum of the assist air amount Qa and the main intake air amount Qm, a map of the sum Q of the intake air amounts corresponding to the operation state is stored in the storage means in advance, and May be configured to compare the intake air amount Qo with the value set in the map and perform a fail determination when Qo <Q.

[Brief description of the drawings]

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

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

FIG. 3 is a flowchart showing assist air supply control.

FIG. 4 is an explanatory diagram of a first map showing an assist air supply region and a supply restriction region.

FIG. 5 is a flowchart showing fuel increase control.

FIG. 6 is an explanatory diagram of a second map showing a feedback zone and a high-load fuel increase zone.

FIG. 7 is an explanatory diagram of a third map showing a feedback zone and an enlarged high-load fuel increasing zone;

FIG. 8 is a block diagram of a control circuit.

FIG. 9 is a flowchart showing ignition timing control.

FIG. 10 is a system diagram showing another embodiment of an exhaust system temperature rise prevention means.

FIG. 11 is a system diagram showing another embodiment of the combustion speed improving means.

[Explanation of symbols]

 Reference numeral 20: injector 21: assist air supply device (combustion speed improving means), Reed
Streak supply means) 24 ... Pressure sensor (fail detection means) 54 ... Fourth step (Second air ratio areaExpansion means) 8 9 DIS (combustion rate improving means), Swirl generating means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI F02M 23/04 301 F02M 23/04 301Z 51/02 69/04 G 69/04 51/02 H (72) Inventor Masayuki Tanaka Hiroshima No.3-1 Shinchi, Fuchu-cho, Aki-gun, Japan Inside Mazda Co., Ltd. (56) References JP-A-2-161152 (JP, A) JP-A-3-54333 (JP, A) JP-A-4-203356 (JP) JP-A-62-78450 (JP, A) JP-A-63-65146 (JP, A) JP-A-62-159748 (JP, A) 2-46071 (JP, U) JP-A 1-166272 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 21/10-45/00 F02M 23/04 F02M 51 / 02 F02M 69/04 F02B 31/00-31/02

Claims (3)

(57) [Claims] (1)If the engine speed is less than the set
When the engine load is in the first air-fuel ratio setting area below the set load,
The air-fuel ratio of the mixture supplied to the engine is set to the first air-fuel ratio
And set the engine speed to the speed set above.
Or the engine load is higher than the set load
Is supplied to the engine when the air-fuel ratio is in the second air-fuel ratio setting area.
The second air, which has a higher air-fuel ratio than the first set air-fuel ratio.
Engine control to reduce exhaust system temperature by setting the ratio
In the device, Fuel speed improving means for improving the combustion speed in the combustion chamber;  A fail detecting means for detecting a failure of the combustion speed improving means.
And when the fail detection means detects a failure.Above setting rotation
Change the number to the low rotation side or set the above load to the low load side.
The second air-fuel ratio area that is changed to expand the second air-fuel ratio setting area
With expansion meansEngine control device. 2. A constitute the burn rate enhancing unit by the assist air supply means for supplying assist air to the injection port near the injector, the second Sorashikahi when deficiency in the assist air
2. The control device for an engine according to claim 1, wherein the control unit activates the setting area expanding unit . 3. A swirl is applied to an air-fuel mixture supplied to a fuel chamber.
The above-mentioned combustion speed improving means is constituted by the swirl generating means.
When the swirl generating means malfunctions.
2. The control device for an engine according to claim 1 , wherein the control unit activates the setting area expanding unit .