JPS6183468A - Control device of engine - Google Patents

Abstract

PURPOSE:To enable a response delay to be prevented, by obtaining a target quantity of air and fuel by an accelerator control quantity and eliminating opening control action exceeding the full opening of a throttle valve when said target quantity of air is above the suction capable quantity of air. CONSTITUTION:A device, obtaining in accordance with an accelerator control quantity detected by an accelerator detecting means 19 a target quantity of air by a target air quantity setting means 30 while a target quantity of fuel by a target fuel quantity setting means 38, concurrently and parallelly controls on the basis of these target quantity values a throttle opening by a throttle valve driving means 37 while a fuel injection valve by a fuel control means 52 so as to obtain the target air-fuel ratio with no response delay. Here the device, if the target quantity of air exceeds a maximum quantity of air determined by an engine speed, both fully opens a throttle valve by a full opening signal generating means 53 and corrects the target quantity of fuel so as to obtain the preset air-fuel ratio by a correcting means 54. In this way, a response delay due to unnecessary control action can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine control device, and in particular, the present invention relates to an engine control device, and in particular, to an accelerator operator indicating a required engine output, the throttle valve is opened (that is, the amount of intake air is controlled) to achieve a predetermined air-fuel ratio. ) and one in which the fuel supply amount is electrically controlled 2D.

(Conventional technology) Conventionally, as a technology for controlling the air-fuel ratio of the engine to a predetermined air-fuel ratio for an accelerator operator who indicates a requested engine output,
As shown in Japanese Unexamined Patent Publication No. 51-138235, there is an accelerator detecting means for detecting an accelerator operator, and an apparatus that receives the output of the accelerator detecting means and controls the air to be supplied to the engine at a preset air-fuel ratio. A target air setting means for setting a target value, and a throttle valve opening degree control means for receiving the output of the target air 15U setting means and controlling the opening of the throttle valve in order to set the air amount to the target value, A system is known in which a target air amount (that is, a target throttle valve opening) is determined in response to the accelerator operation (2), and the throttle valve opening is feedback-controlled for each target air. Then, by supplying the amount of fuel to the engine so that the air-fuel ratio is set in advance according to the amount of intake air that varies depending on the opening degree of the throttle valve, the air-fuel ratio of the engine is set to the target (C). It is.

(Problem to be Solved by the Invention) However, in the above conventional system, the amount of intake air supplied to the engine is controlled by controlling the throttle valve opening.
, the fuel supply amount is controlled to achieve the target air-fuel ratio based on this intake air amount, so the fuel supply direction changes according to the change in the intake air amount, and the air-fuel ratio There is a problem in that the target air-fuel ratio cannot be obtained with high accuracy because variations tend to occur in the target air-fuel ratio. In particular, during transient operation such as engine acceleration or deceleration, the amount of intake air responds immediately to the accelerator operation and changes rapidly. It is not possible to respond immediately, causing a fuel response delay, and during acceleration, the air-fuel ratio becomes overly lean, causing the engine to breathe, and during deceleration, the air-fuel ratio becomes overrich, leading to engine misfires and the like.

The present invention has been made in view of these points, and its purpose is to reduce the amount of intake air for accelerator operation.
By simultaneously controlling the throttle valve opening) and the fuel supply (m) to the target value so that the air-fuel ratio is set in advance, the target air-fuel ratio can be accurately set for the accelerator operator even during transient operation of the engine. The goal is to make things better.

However, in this case, when the target amount of air supplied to the engine exceeds the maximum air amount determined by the engine speed at that time, that is, when the target value is greater than the amount of air that can be taken in when the throttle valve is fully open, the engine If the amount of fuel supplied to the engine is left at the target value, there will be too much fuel compared to the actual amount of intake air supplied to the engine, causing the air-fuel ratio to become overrich, leading to engine misfires and the like. In addition, at this time, when controlling the throttle valve opening, the target value is set to a field with the throttle valve fully open or more, and when controlling the throttle valve opening after that, unnecessary control operation time is required, resulting in a response delay. occurs. Therefore, a further object of the present invention is to determine that the throttle valve is fully open when the target air amount exceeds the maximum air m determined by the engine speed at that time, and to set the target value of the throttle valve opening to the throttle valve fully open value. At the same time, by correcting the target value of fuel supplied to the engine so that it becomes the target air-fuel ratio with respect to the actual intake j at that time, over-rich air-fuel ratio when the throttle valve is fully opened and throttle valve opening control can be prevented. The purpose is to prevent response delays.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention is as follows:
As shown in the figure, an accelerator detecting means 19 for detecting the amount of accelerator operation is installed, and a target 1IfI of air to be supplied to the engine is set by receiving the output of one accelerator detecting means for this accelerator detecting means 19. An air amount setting means 30 and a target fuel amount setting means 38 which similarly receives the output of the accelerator detection means and sets a target value of fuel to be supplied to the engine so as to achieve a preset air-fuel ratio are provided.

Furthermore, a throttle valve driving means 37 receives the output of the target air amount setting means 30 and drives the throttle valve to set the air amount to the target value, that is, to set the throttle valve opening to the target opening; and the target fuel amount. Receiving the output of the setting means 38,
A fuel control means 52 for controlling the fuel supply amount directly to the target is provided. In addition, when the target air amount set by the target air amount setting means 30 exceeds the maximum air amount determined by the engine speed at that time, a full open signal is generated to supply the throttle valve driving means 37 with a signal corresponding to fully opening the throttle valve. and the target fuel amount setting means 38 so that the preset air-fuel ratio is achieved with respect to the intake air amount supplied to the engine when the throttle valve is fully opened by the full open signal generating means 53.
The configuration includes a correction means 54 for correcting the target value of.

(Function) With the above configuration, in the present invention, the target air amount and the target fuel amount are determined according to the accelerator operation amount, and the throttle valve opening degree and the fuel supply amount are determined based on the determined distance 4j:,1m. are controlled in parallel at the same time, even when the engine is operating in a transient state, both the intake air (5) and the fuel supply amount change to the target value at the same time in response to the amount of accessory operation, and the response of the fuel is improved. There is no delay, and the engine air-fuel ratio is accurately controlled to the target air-fuel ratio.

Furthermore, when the target air amount exceeds the maximum air amount determined by the engine speed at that time and the target value is equal to or greater than the amount of air that can be taken in when the throttle valve is fully open, a full open signal is sent to the throttle valve driving means 37. is uttered,
The throttle valve driving means 37 no longer controls the opening of the throttle valve, and there is no response delay due to the unnecessary control operation time during subsequent throttle valve opening control. Moreover, when the throttle valve is fully open, the target fuel amount is corrected to the preset air-fuel ratio for the intake air supplied to the engine, so that the engine's air-fuel ratio does not become overrich. The air-fuel ratio will be well controlled to the target air-fuel ratio.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows the overall configuration of an engine control device according to an embodiment of the present invention, in which 1 is a four-cylinder engine, for example, and 2 has one end opened to the atmosphere via an air cleaner 3 and the other end opened to the engine 1. An intake passage 4 supplies intake air (air) to the engine 1, and an exhaust passage 4 has one end open to the engine 1 and the other end opened to the atmosphere to discharge exhaust gas from the engine 1. Reference numeral 5 indicates an accelerator pedal that is depressed in accordance with the engine output request, and reference numeral 6 indicates a throttle valve that is disposed in the intake passage 2 and controls the intake air m. There is no linkage relationship, and as will be described later, it is electrically controlled by the depression of the accelerator pedal 5, that is, by the accelerator operation (2).

Reference numeral 7 denotes a throttle actuator comprising a step motor or the like that opens and closes the throttle valve 6.

8 is a catalyst installed in the exhaust passage 4 to purify exhaust gas! It is in A position.

Further, 9 has one end opening upstream of the catalyst device 8 of the exhaust passage 4, and Il! An exhaust recirculation passage 10 whose end opens downstream of the throttle valve 6 of the intake passage 2 and which recirculates part of the exhaust gas from the exhaust passage 4 to the intake passage 2; Control the reflux amount. The recirculation control valve consists of a diaphragm [f whose operation source is intake negative pressure. Reference numeral 11 is a solenoid valve that controls opening and closing of the recirculation control valve 10.

On the other hand, reference numeral 12 denotes a fuel injection valve disposed downstream of the throttle valve 6 in the intake passage 2 to inject and supply fuel. The fuel tank 16 is connected to the fuel tank 16 through the fuel tank 16, and fuel is supplied from the fuel tank 16, and the surplus fuel is returned to the fuel tank 16 through a return passage 18 with a fuel pressure regulator 17 interposed therebetween. Therefore, fuel at a predetermined pressure is supplied to the fuel injection valve 12.

In addition, 19 is an accelerator pedal position pincer as an accelerator detection means for detecting the depression position of the accelerator pedal 5, that is, the accelerator operator α, and 20 is an accelerator pedal position pincer arranged upstream of the throttle valve 6 in the intake passage 2 to detect the intake air ff1QaR. 21 is an intake temperature sensor that is also arranged upstream of the throttle valve 6 in the intake passage 2 and detects the intake air temperature; 22 is a throttle position sensor that detects 17fla of the throttle valve 6; 23 is an engine cooling water sensor; A water temperature sensor 24 detects the temperature I/Tw; 02 sensor 24 is disposed upstream of the catalyst device 8 in the exhaust passage 4 and detects the air-fuel ratio λ of the engine 1 from the oxygen concentration component in the exhaust gas;
Reference numeral 25 denotes a reflux sensor attached to the reflux control valve 1o to detect the time of 1-node air reflux, and these detection signals 19 to 25 are input to a control unit 26 consisting of an analog combination coater, etc. 26 controls the throttle actuator 7, solenoid valve 11, and fuel injection valve 12. Roughly,
An igniter 27 is input connected to the control unit 26, and the number of ignitions, that is, the engine speed No.
signal is being input. Further, a dust distributor 28 and two batteries are connected as inputs to the control unit 26, and receive signals of ignition timing and battery voltage Ve, respectively.

Next, the operation of the control unit 26 will be explained with reference to FIG. Note that FIG. 3 shows the case of a four-cylinder engine.

In FIG. 3, first, to describe the throttle valve opening control system, MAI is set to a target value Qa of air to be supplied to the engine 1 so that the air-fuel ratio is set in advance in response to the accelerator operation mα. The first map constitutes a target air carrier setting means 30 which receives the output from the accelerator pedal position sensor 19 and sets the target air ff1Qa1 to be supplied to the engine 1 in response to the accelerator operation ■α. MA2 is the minimum air m to achieve the air-fuel ratio required for idle up with respect to the engine cooling water temperature Tw.
This is a second map in which Q am is set, and the minimum air ffI Q am for water temperature correction is set in response to the output from the water temperature sensor 23 according to the engine cooling water temperature Tw. 31 is the first map MAI (target air setting means 30) and ? After receiving each output of A2 map MA2, the target air ff1 obtained from the first map ~+AI
The maximum 11t [Qa
This is a maximum value selection circuit that selects the target air ff.
When 1Qa+ is lower than the minimum air for water temperature correction 11 Q am, the minimum air for water temperature correction fl is increased to increase the idle.
Q am is selected to ensure good engine operability. Moreover, MA3 is the maximum air ff determined by the engine speed Ne with respect to the engine speed Ne.
This is the third map in which iQaM is set, and receives the output from the igniter 27 and sets the maximum air amount QaM according to the engine speed Ne. 32 receives each output of the maximum value selection circuit 31 and the third map MA3, and receives the maximum air ff determined by the maximum value selection circuit 31.
Maximum air m obtained from 1Qa 2 and the third map M^3
The minimum (1
11I selection circuit, therefore, when the target air mQa1 exceeds the maximum air faQaM determined by the engine speed Ne, the throttle valve 6 is fully open to aim for air that is greater than or equal to the air that can be taken in (it is meaningless even if it is set directly). Therefore, by selecting -F2 maximum air ffiQaM and limiting the maximum value, a fully open signal corresponding to all 17n of throttle valves 6 is supplied to the throttle valve driving means 37, which will be described later. The means 53 constitutes the means 53. As described above, the engine cooling water r
A target air m Q, a 3 is determined taking into consideration the correction for A T w and the correction for the maximum air amount when the throttle valve 6 is fully open, which is determined by the engine speed Ne.

Furthermore, 33 receives the output from the maximum value selection circuit 32, and selects the target air ff1Qa3 at the engine rotational speed Ne.
This is a filter that removes the air by 1irl (N, e
I'm looking for +. MAI and ~IA5 are the fourth and fifth maps in which the throttle valve opening θ1 or θ1ε that should be the target intake mAc+ for the engine speed Ne at J5 when exhaust gas recirculation is stopped and when exhaust gas recirculation is stopped, respectively; N-=to IAJIM 5 is selected by the recirculation switch 34 which switches between exhaust recirculation stop and exhaust recirculation according to the signal from the recirculation sensor 25, receives the output from the defanger 33, and should be set to the target intake air ff1Ac+. The throttle valve opening degree θI or θIE is set. Further, 35 is an intake air amount feedback correction module, which outputs the target intake air ff1Ac from the mouth eliminator 33.
Upon receiving the + signal, the air flow meter 20
The signals of large air suspension QaR and engine rotation speed Ne measured by
Actual intake air per cylinder ff1Ac calculated by x e
R and the target intake air ff1Ac+ are compared, and a feedback correction coefficient CaFB for feedback correcting the throttle valve opening is determined according to the difference. Furthermore, 36 is the fourth or fifth map ~1A4
．． ~485J5 and the intake air amount feedback correction module 35, the maps MAa, MA
A multiplier that corrects the target throttle valve opening θ1 or θIE obtained by s by the feedback correction coefficient CaFer obtained by the intake air amount feedback correction module 35, the target throttle valve opening corrected by the multiplier 36. The signal θ2 is output to the throttle actuator unique 7, and the opening degree of the throttle valve 6 is controlled to the target throttle valve opening degree θ2. As described above, upon receiving the output of the target fuel amount setting means 30, the throttle valve 6
It constitutes a throttle valve driving means 37 that drives and controls the.

Next, to describe the old fuel supply system in FIG.
A sixth map in which direct Qf+ is set, which receives the output from the accelerator pedal position sensor 19 and determines the target fuel m to be supplied to the engine 1 according to the accelerator operation (5) α.
It constitutes target fuel amount setting means 38 for setting Qf+. MB7 is the seventh map in which the minimum fuel amount Qfm for the engine cooling water/g degree Tw is set so that the air fuel ratio necessary for idle up is obtained for the air amount Qam set in the second map MA2. Then, upon receiving the output of the water temperature sensor 23, the minimum fuel for water temperature correction fiQfm is set according to the engine cooling water temperature Tw. Three receive the respective outputs of the sixth map M06 (target fuel amount setting means 38) and the seventh map MB7, and calculate the target fuel ff1Qf+ determined by the sixth map Ma6 and the seventh map May.
This is a maximum value selection circuit that selects the maximum value Qfz of the minimum fuel lQfm for water temperature correction obtained in The minimum fuel mQfm is selected to ensure good engine operability. In addition, Maa is the third map MAJ
This is the eighth map in which the maximum fuel (fkQf Set fuel mQfM. 40 is the maximum value selection circuit 39 and the eighth
In response to each output of map MB8, the maximum (minimum one direct Qf that is the difference between the maximum fuel ff1Qfz found by the three direct selection circuits and the maximum fuel mQfM found by the eighth map Msa)
This is a minimum value selection circuit that selects IR and selects the above target fuel f.
When f1Q[1 exceeds the maximum fuel FJQfM determined by the engine speed Nc, that is, as mentioned above, the target air ff1Qa+ exceeds the maximum air mQaM determined by the engine speed Ne, and the throttle valve 6 is fully opened to intake air. When the throttle valve is fully opened by the fully open 1Δ number generating means 53, which has a target value of ■ which is more than the possible air m, the maximum air ffiQaM is selected and the maximum fuel ER is selected.
a correction means 5 which selects Qf M and corrects the target value Of+ of the target fuel amount setting means 38 so that the intake air m supplied to the engine 1 reaches a preset target air-fuel ratio;
4. As described above, similarly to the case of air m, engine cooling water temperature Tw is
The target fuel ff1Qf3 is determined by taking into consideration the correction for the maximum fuel charge when the throttle valve 6 is fully open, which is determined by the engine speed Ne.

Then, the target fuel ff1 from the maximum value selection circuit 40 is
The Qf3 signal is transmitted through the divider 41 and the first to third multipliers 42 to 4.
4. It is output to the fuel injection valve 12 via the fuel injection valve correction circuit 46 and the fuel injection valve correction circuit 45. The divider 41 receives the output from the minimum (direct selection circuit 40) and divides the target fuel (5) Q[1 by the engine rotational speed Ne assuming that fuel is injected into two cylinders at the same time. In addition, the first multiplier 42 calculates the target shape W1 supply suspension Q fi obtained by the divider 41 by the ninth map M8. Water temperature correction coefficient CT for engine cooling water temperature Tw
W and the enrichment correction coefficient CER obtained by the enrichment correction module 47 to correct the target fuel supply f.
This interferes with f1Qfi+. This engine rich correction module 47 is a zone determination module 51 which will be described later.
Based on the zone signal from the engine rotation speed Ne, when the intake air mΔC1 is within the enrichment line (1 region), an enrichment correction coefficient CεR (for example, 1.08) is output to increase the fuel supply amount by, for example, 8%. It is something.

Furthermore, the above-mentioned No. 251'! The calculator 43 is a first multiplier/stopper 42
Target fuel supply ff! Q f i +,
The target fuel supply ff1Qfi2 is determined by multiplying and correcting by the learning correction coefficient C3TD obtained by the fuel science circle correction module 48. This fuel learning correction module 48
is based on the zone signal from the zone determination module 51 and the fuel feedback correction coefficient CI'FB from the fuel feedback correction module 49, which will be described later.
When the fuel feedback correction conditions are satisfied in the four fuel feedback correction modules, for example, after 2 seconds or more, the fuel learning correction coefficient C3TD is changed to its initial value - 1, 0.
Then, it is sequentially updated and output using the following formula % CfFB peak value + past 8 Crps (7) bottom 1lfI)/16-1.0).

Further, the third multiplier/stop device 44 multiplies and corrects the target fuel supply amount Qfi2 obtained by the second multiplier/cylinder device 43 by the fuel feedback correction coefficient Cf1 day obtained by the fuel feedback correction module 4 to achieve the target fuel supply amount Qfi2. Fuel supply amount Q fi3
This is something that causes problems. This fuel feedback correction module 49 detects the zone signal from the zone determination module 51 and the air-fuel ratio λ signal from the 02 sensor 24, and detects, for example, the following conditions: ■ Engine cooling water temperature Tw > 60°C ■ Intake air amount Act ≧ cylinder stroke volume 10% ■ The intake air (5) Δc1 relative to the engine speed Ne is outside the enrich line and the tsuyuel power cut zone ■ The O2 sensor 24 is active, then the fuel feedback correction coefficient is set to feedback control the fuel supply amount. (jF day <For example 0.8
≦CfFe≦1.25, proportional constant P=0.06, integral constant 1=0.05/sec).

Furthermore, the opening and closing of the twin cut switch 45 is controlled by an output signal from the twin cut control module 50. This twin air cut control module 50 operates based on the zone signal and target intake mAc+ signal from the zone determination module 51, and operates under the following conditions, for example: ■ Engine cooling water temperature Tw>60°C ■ Intake air ff1Ac+<10% of cylinder stroke volume■
When the engine rotation tfflN'e exceeds 100 Orpm, there is a need to listen to and control the twin fuel cut switch 45 to cut fuel injection. Here, the zone determination module 51 determines the engine rotation speed Ne,
01 to the target intake air amount, the respective control modules 47 based on the signals of the engine cooling water temperature a T w and the air-fuel ratio λ.
-50 conditional judgments (zone signals) are created.

In addition, the fuel r[injection valve correction circuit 46 calculates the target fuel supply Ff from the third multiplier 44, Q f i
3 signal and battery voltage V day signals from two batteries, corrects a pulse signal as a target fuel supply amount signal to the fuel injection valve 12 according to the battery voltage Ve, and outputs the corrected pulse signal to the fuel injection valve 12. be. As described above, the fuel injection valve 12 is driven for a predetermined time at the same time as ignition, and the fuel supply amount is controlled to the target vA value.
It constitutes the I211 means 52.

Therefore, as described above, the target air borrow setting means 30 determines whether the accelerator operation amount α is the target value or not. The target fuel amount setting means 38 determines the amount of air on the same side of the throttle valve 6 (in other words, the amount of intake air The amount of fuel supplied from the fuel injection valve 12 is simultaneously controlled to zero by the fuel control means 52 so as to be on target in parallel, so that Since the intake air amount and fuel supply amount both change to the target value at the same time without any time lag, there is no delay in fuel response even during transient operation of the engine, and the air-fuel ratio of the engine is maintained. It is possible to precisely control the air-fuel ratio I'?i to the target air-fuel ratio, thereby improving the acceleration performance and driving performance of the engine without causing engine sluggishness or misfires as in the conventional case.

Moreover, since the intake air amount and fuel supply amount are simultaneously controlled in response to the accelerator operation (￥ amount α) so that the air-fuel ratio is set in advance, the target air-fuel ratio can be achieved accurately without the need for feedback control. Therefore, the control can be simplified.

Furthermore, when the target air m determined by the target air amount setting means 30 blocks the third map MAh and exceeds the maximum air port determined by the engine speed Ne at that time, the amount of air m that can be taken in when the throttle valve 6 is fully opened is exceeded. is set as the target value, and the fully open signal generating means 53 supplies the throttle valve driving means 37 with a signal corresponding to the fully opening of the throttle valve 6.
It is possible to eliminate the unnecessary control operation of the throttle valve opening based on the target air pressure according to 7, and prevent the response delay caused by the unnecessary control operation time when controlling the throttle valve opening after that. Good δ-responsiveness of temperature control can be ensured.

Moreover, when the throttle valve 6 is fully opened by the full open signal generating means 53, the target value of the target fuel amount setting means 38 is set in the eighth map MG11 so that the air-fuel ratio is set in advance for the intake air amount supplied to the engine 1. Since the correction is made based on the fully open throttle valve 6 +1', '+t
? It is possible to prevent the deterioration of the air-fuel ratio (overridge formation) of the air-fuel ratio, and therefore always achieve the target air-fuel ratio with high accuracy.
B property can be ensured.

(Effects of the Invention) As explained above, according to the present invention, the throttle valve opening (intake air m) and the fuel supply amount are simultaneously controlled based on the target air amount and target fuel amount determined by the accelerator operation amount. Since the target air-fuel ratio is adjusted to each target value in parallel to obtain the target air-fuel ratio according to the accelerator operation amount, there is no fuel delay even during transient operation of the engine, and the engine air-fuel ratio can be accurately adjusted to the target air-fuel ratio. control, and can improve acceleration performance and driving performance. Furthermore, by simultaneously controlling the intake air □□□ and each fuel supply, it is possible to precisely control the air-fuel ratio to a preset target air-fuel ratio without requiring feedback control, simplifying the control. It also has a decay point that can be used to measure the corrosion resistance.

Further, in the present invention, when the target air amount exceeds the maximum air m determined by the engine speed at that time and the target value is set to a value equal to or more than the air m that can be taken in when the throttle valve is fully opened, the throttle valve is fully opened. By eliminating the above-mentioned control operation, it is possible to prevent response delays caused by unnecessary control U operation, and to set the target fuel density at full throttle valve opening to the amount of intake air supplied to the engine. Since the air-fuel ratio is corrected to prevent over-richness, the target air-fuel ratio can be accurately controlled even when the throttle valve is fully open.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 and 3 show an embodiment of the present invention, with FIG. 2 being a general schematic diagram and FIG. 3 being a block diagram showing the operational flow of the control unit. 1...Engine, 5...Accelerator pedal, 6...
Throttle valve, 7... Throttle actuator, 1
2.;・Fuel injection valve, 1...Accelerator pedal position sensor, 26...Control unit, 30.
...Target air amount setting means, 37... Throttle valve drive 3 means, 38... Target fuel ffi setting means, 52...
- Fuel 1i110n means, 53...Full-open signal generation means, 54...Correction means. J is-)

Claims (1)

[Claims] (1) Accelerator detection means for detecting the amount of accelerator operation;
a target air amount setting means that receives the output of the accelerator detection means and sets a target value of air to be supplied to the engine; and a target air amount setting means that receives the output of the accelerator detection means and supplies the air to the engine at a preset air-fuel ratio. Target fuel amount setting means for setting a target value of fuel; Throttle valve driving means for receiving the output of the target air amount setting means and driving a throttle valve to set the air amount to the target value; and the target fuel amount setting means. a fuel control means for controlling the fuel supply amount to a target value based on the output of the above; and when the target air amount set by the target air amount setting means exceeds the maximum air amount determined by the engine speed at that time, the throttle valve driving means; a full-open signal generating means for supplying a signal corresponding to a fully open throttle valve; and a full-open signal generating means for generating the target fuel so that the preset air-fuel ratio is achieved with respect to the intake air amount supplied to the engine when the throttle valve is fully opened. 1. A control device for an engine, comprising: correction means for correcting a target value of the quantity setting means.