JPH11324772A - Internal combustion engine - Google Patents

Abstract

(57) [Problem] To improve the response of the feedback control of the rotation speed in the compression lean mode when performing the feedback control of the rotation speed. When an air conditioner switch (71) is turned on during idling operation, for example, a command from an ECU (61) is issued.
In the case of the compression lean mode, the feedback of the rotation speed is prohibited during a short period of time when the rotation speed is stabilized by changing the fuel amount, which is set by the rotation speed feedback prohibition timer for the compression lean mode, and the intake stroke injection is performed. In the case of the mode, the feedback of the rotational speed is prohibited while the rotational speed stabilizes due to the change of the air amount longer than the time t set by the rotational speed feedback prohibition timer for the intake stroke injection mode, When implementing the feedback control of the rotation speed, the responsiveness of the feedback control of the rotation speed in the compression lean mode is improved, and
The stability of the feedback control in the intake stroke injection mode is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine in which fuel injection is performed at least during an intake stroke and a compression stroke, and aims at improving the responsiveness of feedback control of the rotational speed.

[0002]

2. Description of the Related Art In a general four-cycle internal combustion engine (MPI engine) in which fuel is injected into an intake pipe and mixed with intake air to introduce an air-fuel mixture into a combustion chamber, the rotational speed during idling operation Feedback control is performed,
The intake air amount is changed so that the actual rotation speed becomes a preset target rotation speed (idle speed control: ISC).

In the conventional ISC control, when an external load such as an air conditioner or power steering is turned on, an ISC
The valve is opened to increase the amount of intake air to increase the rotation speed. At this time, there is a time difference between the operation state of the ISC valve and the actual increase state of the intake air amount, and the intake air amount is not immediately increased. Therefore, when the feedback control of the rotation speed is continued, the predetermined amount of the intake air amount is introduced. The feedback control is performed in a state where the actual rotation speed does not increase in spite of the state where the rotation speed is obtained, and the control is over-controlled. Therefore, the feedback control of the rotational speed is prohibited until a predetermined period elapses from the opening of the ISC valve until the intake air amount is stabilized, thereby preventing overcontrol.

In recent years, in order to reduce harmful exhaust gas components and improve fuel efficiency, a multi-cylinder in-cylinder injection engine that injects fuel directly into a combustion chamber, instead of an intake pipe injection engine that injects fuel into an intake pipe. Have been proposed. The multi-cylinder direct injection engine includes an intake stroke injection mode (intake lean mode) in which fuel is mainly injected in an intake stroke,
A compression stroke injection mode (compression lean mode) in which fuel injection is mainly performed in the compression stroke is switched according to the operation state. Further, during idle operation, feedback control of the rotation speed is performed so that the actual rotation speed becomes the target rotation speed set in advance.

In the above-described multi-cylinder in-cylinder injection engine, in the compression lean mode, the combustible air-fuel ratio is wide, and the rotation speed is easily changed by changing the air-fuel ratio. Therefore, the feedback control of the rotation speed is performed by changing the air-fuel ratio. Has been implemented. In the intake stroke injection mode, the flammable air-fuel ratio is set in a narrow range near stoichio. Therefore, it is difficult to change (increase) the rotation speed by changing the air-fuel ratio. Therefore, by changing the intake air amount similarly to the MPI engine, The feedback control of the rotation speed is performed.

When an external load such as an air conditioner or power steering is turned on, the air-fuel ratio is changed to increase the rotation speed in the compression lean mode, and the intake air amount is changed in the intake stroke injection mode. The rotation speed is increased. In this case, after the rotation speed is controlled to be higher, feedback control of the rotation speed is prohibited until the rotation speed becomes stable after a predetermined time has elapsed, thereby preventing over-control.

[0007]

In the above-described multi-cylinder in-cylinder injection engine, the predetermined period during which the feedback control of the rotational speed is prohibited is set to be the same in the compression lean mode and the intake stroke injection mode. However, when the rotation speed is increased in the compression lean mode, the response of the rotation speed is good because the fuel amount is changed, and a shorter period than in the intake stroke injection mode in which the rotation speed is increased by changing the intake air amount. And the rotation speed is stabilized. For this reason, in the compression lean mode, the period in which the feedback control is prohibited is long, and a useless prohibition period is set.

[0008] The present invention has been made in view of the above circumstances, and when changing the rotation speed when an external load is applied,
An object of the present invention is to provide an internal combustion engine that can improve the responsiveness of feedback control of rotation speed.

[0009]

According to the structure of the present invention for achieving the above object, the actual rotation speed of the engine is previously set by changing the intake air amount during the intake stroke and changing at least the fuel amount during the compression stroke. Control means for performing feedback control of the rotation speed so as to achieve the target rotation speed, prohibiting the feedback control of the rotation speed by a prohibition means when an external load is applied for a predetermined period, and setting the predetermined period to the intake stroke by the setting means. It is characterized in that it is set separately in the compression process.

More specifically, the feedback control prohibition period in the compression lean mode in which the rotation speed is increased by changing the fuel amount when an external load such as an air conditioner is applied,
It is set shorter than the prohibition period of the feedback control in the intake stroke injection mode in which the rotation speed is increased by changing the intake air amount, to ensure the stability of the feedback control in the intake stroke injection mode and to provide feedback in the compression lean mode. Improve control responsiveness.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In the illustrated embodiment, a multi-cylinder in-cylinder injection internal combustion engine in which fuel is directly injected into a combustion chamber is described as an internal combustion engine. FIG. 1 shows a schematic configuration of a multi-cylinder direct injection internal combustion engine according to an embodiment of the present invention, and FIG. 2 shows a fuel injection control map.

The configuration of a multi-cylinder direct injection internal combustion engine will be described with reference to FIG. As the multi-cylinder in-cylinder injection internal combustion engine, for example, an in-cylinder injection type in-line 4-cylinder gasoline engine (in-cylinder injection engine) 1 that directly injects fuel into a combustion chamber is applied. In the direct injection engine 1, a combustion chamber, an intake device, an exhaust gas recirculation device (EGR device), and the like are designed exclusively for direct injection.

The cylinder head 2 of the in-cylinder injection engine 1 is provided with an ignition plug 3 for each cylinder and an electromagnetic fuel injection valve 4 as a fuel supply means for each cylinder. The injection port of the fuel injection valve 4 is opened in the combustion chamber 5, and the fuel injected from the fuel injection valve 4 via the driver 20 is directly injected into the combustion chamber 5. A piston 7 is supported on the cylinder 6 of the in-cylinder injection engine 1 so as to be slidable in a vertical direction, and a cavity 8 which is depressed in a hemispherical shape is formed on a top surface of the piston 7.
The cavity 8 generates a reverse tumble flow in the intake flow, which is opposite to a normal tumble flow.

An intake port 9 and an exhaust port 10 facing the combustion chamber 5 are formed in the cylinder head 2.
Is opened and closed by the drive of the intake valve 11, and the exhaust port 10
Is opened and closed by driving the exhaust valve 12. An intake side camshaft 13 and an exhaust side camshaft 14 are rotatably supported on the upper part of the cylinder head 2. The rotation of the intake side camshaft 13 drives the intake valve 11, and the exhaust side camshaft 14 The rotation drives the exhaust valve 12. The exhaust port 10 has a large-diameter exhaust gas recirculation port (EGR port) 15 branched diagonally downward.

In the vicinity of the cylinder 6 of the direct injection engine 1, a water temperature sensor 16 for detecting a cooling water temperature is provided. In addition, a predetermined crank position of each cylinder (for example, 75 degree BT
A vane-type crank angle sensor 17 that outputs a crank angle signal SGT at DC and 5 degrees BTDC) is provided, and the crank angle sensor 17 can detect the engine rotation speed. The camshafts 13 and 14 which rotate at half the number of rotations of the crankshaft are provided with an identification sensor 18 for outputting a cylinder identification signal SGC, and the cylinder identification signal SGC can identify which cylinder the crank angle signal SGT belongs to. It has been. Reference numeral 19 in the figure denotes an ignition coil for applying a high voltage to the ignition plug 3.

An intake pipe 40 is connected to the intake port 9 via an intake manifold 21, and the intake manifold 21 is provided with a surge tank 22. In addition, the intake pipe 4
0 is provided with an air cleaner 23, a throttle body 24, a first air bypass valve 25 of a stepper motor type, and an air flow sensor 26. Air flow sensor 26
Detects the amount of intake air. For example, a Karman vortex flow sensor is used. The surge tank 22
A boost pressure sensor may be attached to the intake pipe, and the intake air amount may be obtained from the intake pipe pressure detected by the boost pressure sensor.

The intake pipe 40 is provided with a large-diameter air bypass pipe 27 for bypassing the throttle body 24 and sucking air into the intake manifold 21.
Is provided with a second air bypass valve 28 of a linear solenoid type. The air bypass pipe 27 has a flow passage area similar to that of the intake pipe 40, and when the second air bypass valve 28 is fully opened, intake of an amount required in the low to medium speed region of the in-cylinder injection engine 1 is possible.

The throttle body 24 is provided with a butterfly type throttle valve 29 for opening and closing a flow path.
A throttle position sensor 30 for detecting the opening of the throttle valve 29 is provided. From a throttle position sensor 30 that detects the opening of the throttle valve 29,
A throttle voltage corresponding to the opening of the throttle valve 29 is output, and the opening of the throttle valve 29 is recognized based on the throttle voltage. The throttle body 24 is provided with an idle switch 31 that detects the fully closed state of the throttle valve 29 and recognizes the idling state of the in-cylinder injection engine 1.

On the other hand, an exhaust pipe 33 is connected to the exhaust port 10 via an exhaust manifold 32, and an O ₂ sensor 34 is attached to the exhaust manifold 32. Also,
The exhaust pipe 33 is provided with a three-way catalyst 35 and a muffler (not shown). The EGR port 15 is a large-diameter EG.
An EGR pipe 36 is connected to an upstream side of the intake manifold 21 via an R pipe 36, and a stepper motor type E
A GR valve 37 is provided.

The fuel stored in the fuel tank 41 is sucked up by an electric low-pressure fuel pump 42 and supplied to the in-cylinder injection engine 1 via a low-pressure feed pipe 43. The fuel pressure in the low pressure feed pipe 43 is regulated to a relatively low pressure (low fuel pressure) by a first fuel pressure regulator 45 provided in a return pipe 44. The fuel supplied to the in-cylinder injection engine 1 is supplied to each fuel injection valve 4 by a high-pressure fuel pump 46 via a high-pressure feed pipe 47 and a delivery pipe 48.

The high-pressure fuel pump 46 is, for example, of a swash plate axial piston type, is driven by an exhaust-side camshaft 14 or an intake-side camshaft 13, and has a predetermined pressure or more even during idling operation of the direct injection engine 1. Discharge pressure can be generated. The fuel pressure in the delivery pipe 48 is regulated to a relatively high pressure (high fuel pressure) by a second fuel pressure regulator 50 provided in the return pipe 49.

An electromagnetic fuel pressure switching valve 51 is attached to the second fuel pressure regulator 50. When the fuel pressure switching valve 51 is turned on, the fuel is relieved and the fuel pressure in the delivery pipe 48 can be reduced to a low fuel pressure. It is. Reference numeral 52 in the drawing denotes a return pipe for returning a part of the fuel used for lubrication and cooling of the high-pressure fuel pump 46 to the fuel tank 41.

The vehicle is provided with an electronic control unit (ECU) 61 as a control device. The ECU 61 includes an input / output device, a storage device for storing a control program and a control map, a central processing unit, a timer and a counter. Kind is provided. Comprehensive control of the direct injection engine 1 is performed by the ECU 61. The detection information of the various sensors described above is input to the ECU 61, and the ECU 61 determines the fuel injection mode, the fuel injection amount, the ignition timing, the amount of EGR gas introduction, etc., based on the detection information of the various sensors, The driver 20 of the injection valve 4 and the ignition coil 19, E
Drive control of the GR valve 37 and the like is performed.

The input side of the ECU 61 is connected to a large number of external load switches (not shown) such as an air conditioner switch 71 in addition to the various sensors described above. And devices are connected.

In the above-described in-cylinder injection engine 1, when the in-cylinder injection engine 1 is in a cold state, when the driver turns on the ignition key, the low-pressure fuel pump 42 and the fuel pressure switching valve 51 are turned on, and the fuel injection is performed. Low fuel pressure fuel is supplied to the valve 4. Next, when the driver operates the ignition key to start, the in-cylinder injection engine 1 is cranked by a cell motor (not shown).
1 is started.

At this time, the ECU 61 selects the first injection mode (ie, the intake stroke injection mode in which fuel is injected in the intake stroke), and the fuel is injected so as to have a relatively rich air-fuel ratio.

At the time of such a start, the second air bypass valve 28 is closed to almost the vicinity of the fully closed state. Therefore, the intake air to the combustion chamber 5 is performed through the gap of the throttle valve 29 and the first air bypass valve 25. The first air bypass valve 25 and the second air bypass valve 28 are connected to the ECU 6
1, the respective valve opening amounts are determined according to the required amount of intake air bypassing the throttle valve 29.

When the in-cylinder injection engine 1 is thus started and the in-cylinder injection engine 1 starts idling at a predetermined rotational speed, the high-pressure fuel pump 46 starts rated discharge operation. The fuel pressure switching valve 51 is turned off, and high-pressure fuel is supplied to the fuel injection valve 4.
The required fuel injection amount at this time is obtained from the discharge pressure of the high-pressure fuel pump 46 and the valve opening time of the fuel injection valve 4.

Until the cooling water temperature detected by the water temperature sensor 16 rises to a predetermined value, the first injection mode is selected and fuel is injected as in the case of starting. The control of the idle speed according to the increase or decrease of the load on the auxiliary equipment such as the air conditioner is performed by the first air bypass valve 25. When the predetermined cycle elapses and the O ₂ sensor 34 is activated, the air-fuel ratio feedback control is started according to the output voltage of the O ₂ sensor 34. Thereby, the harmful exhaust gas components are favorably purified by the three-way catalyst 35.

When the warm-up of the direct injection engine 1 is completed,
The ECU 61 calculates the current fuel injection range from the fuel injection map of FIG. 2 based on a target output correlation value obtained from a throttle voltage corresponding to the opening of the throttle valve 29, for example, the target average effective pressure Pet and the engine speed Ne. To determine the fuel injection mode. Thus, the fuel injection amount according to the target air-fuel ratio in each fuel injection mode is determined, and the drive of the fuel injection valve 4 and the drive control of the ignition coil 19 are performed according to the fuel injection amount. At the same time, opening / closing control of the first air bypass valve 25, the second air bypass valve 28, and the EGR valve 37 is also performed.

In a low load region such as during idling or low-speed running, the fuel injection region is selected to be the late injection lean mode in FIG. 2 (that is, the compression lean mode in which fuel is injected in the compression stroke). In this case, the first air bypass valve 25
And the second air bypass valve 28 are controlled, and a target air-fuel ratio corresponding to the target average effective pressure Pet is set based on the throttle voltage and the engine speed Ne so as to obtain a lean air-fuel ratio. Then, a fuel injection amount according to the target air-fuel ratio is set, and the drive of the fuel injection valve 4 is controlled so as to perform fuel injection according to the fuel injection amount.

In the middle load region such as when the vehicle is traveling at a constant speed, the injection lean mode or the stoichiometric feedback mode in FIG. 2 is set according to the load condition and the engine speed. In the first-stage injection lean mode, the first air bypass valve 25 is controlled in the same manner as a normal idle speed control valve, and the target air-fuel ratio is calculated according to the intake air amount signal from the air flow sensor 26 and the engine speed.
The fuel injection amount is controlled so as to have a relatively lean air-fuel ratio.

In the stoichiometric feedback mode, as in the previous injection lean mode, the first air bypass valve 25
Is controlled in the same manner as a normal idle speed control valve, the second air bypass valve 28 is fully closed to prevent an excessive increase in output, the EGR valve 37 is controlled to be almost fully closed, and the target air-fuel ratio is controlled. The air-fuel ratio feedback control is performed according to the output voltage of the O ₂ sensor 34 so that the fuel injection amount becomes the stoichiometric air-fuel ratio, and the fuel injection amount is controlled.

In a high load region such as during rapid acceleration or high-speed running, the open loop mode shown in FIG. 2 is set. In this case, the second air bypass valve 28 is closed, and a target air-fuel ratio is set from a map so as to have a relatively rich air-fuel ratio, and the fuel injection amount is controlled according to the target air-fuel ratio.

In the above-described in-cylinder injection engine 1, the actual rotation speed during the idling operation in which the idle switch 31 is turned on becomes the target rotation speed set in advance.
The feedback control of the rotation speed is performed. In the compression lean mode, the flammable air-fuel ratio is wide, and the rotation speed is easily changed by changing the air-fuel ratio.Therefore, changing the air-fuel ratio changes the fuel injection amount and intake air amount supplied to the engine to reduce the rotation speed. Feedback control is implemented. In the intake stroke injection mode, feedback control of the rotational speed is performed by changing the amount of intake air.

When an external load such as the air conditioner switch 71 or power steering is turned on, in the compression lean mode, the air-fuel ratio is changed at least by changing the fuel injection amount to increase the rotation speed, and the intake stroke is changed. In the injection mode, the rotation speed is increased by changing the intake air amount (control means). In this case, after the rotation speed is controlled to be high, feedback control of the rotation speed is prohibited to prevent over-control until the rotation speed is stabilized after a predetermined period has elapsed (prohibited. means). The predetermined period during which the feedback control is prohibited until the rotation speed is stabilized is set separately in the compression lean mode and the intake stroke injection mode (setting means).

FIG. 3 shows a situation when the external load is turned on while the above-described in-cylinder injection engine 1 is performing the feedback control of the rotational speed during the idling operation.
This will be described with reference to FIGS. FIG. 3 shows a change over time in the compression lean mode, FIG. 4 shows a change over time in the intake stroke injection mode, and FIGS. 5 and 6 show flowcharts of feedback control of the rotational speed during the idling operation.

As shown in FIG. 3, when the feedback control of the rotation speed is performed so that the actual rotation speed during idling operation in the compression lean mode becomes the preset target rotation speed, the load becomes an external load. When the air conditioner switch 71 (power steering switch, light switch, wiper switch, etc.) is turned on, the fuel coefficient increases, the fuel amount increases, and the air-fuel ratio changes. At the same time, the feedback control of the rotation speed is prohibited. In addition, for example, the first air bypass valve 25
Opens and the air volume is increased. Thus, the rotation speed during idling operation in the compression lean mode is increased.

By changing the fuel amount and increasing the rotation speed, the rotation speed is stabilized at a predetermined rotation speed in a short time after the fuel amount is increased. The feedback control timer for the rotation speed for the lean mode is activated, and the feedback control of the rotation speed is prohibited for a short time t, and the feedback control is resumed after the elapse.

In the compression lean mode, since the rotation speed is high and stable with good responsiveness due to the correction based on the fuel amount, the feedback control of the rotation speed is prohibited only for a short time t, and the responsiveness of the feedback control of the rotation speed is reduced. Is improved.

On the other hand, as shown in FIG. 4, when feedback control of the rotational speed is performed so that the actual rotational speed during idling operation in the intake stroke injection mode becomes the preset target rotational speed, the external When the air conditioner switch 71 (power steering switch, light switch, wiper switch, etc.) as a load is turned on, for example, the first air bypass valve 25 is opened to change the air amount, and the fuel amount is changed accordingly. Thus, the rotation speed during the idling operation in the intake stroke injection mode is increased.

In the case of increasing the rotation speed by changing the air amount, for example, since there is a time from when the first air bypass valve 25 is opened to when the air amount increases, the rotation speed is increased after the predetermined time elapses. Stabilizes at the rotational speed of. For this reason,
After the air conditioner switch 71 is turned on, the feedback inhibition timer for the rotation speed for the intake stroke injection mode is activated, and for a longer time T than in the compression lean mode,
The feedback control of the rotation speed is prohibited, and after the elapse, the feedback control is restarted.

In the case of the intake stroke injection mode, a time lag occurs in the increase in the amount of air. Therefore, the feedback control of the rotation speed is prohibited during the time T when the time lag is eliminated, and the stability of the feedback control is ensured.

The situation during the idling operation described above will be described with reference to FIGS.

As shown in FIG. 5, in step S1, it is determined whether or not the idle switch 31 is turned on. If it is determined that the idle switch 31 is not turned on, the operation returns because the operation is not idling. If it is determined in step S1 that the idle switch 31 is ON, the operation is the idle operation. Therefore, it is determined in step S2 whether the external load signal has changed, for example, whether the air conditioner switch 71 has been turned ON. You.

If it is determined in step S2 that the air conditioner switch 71 has been turned on, it is determined in step S3 whether the operation is in the compression lean mode. If it is determined in step S3 that the mode is the compression lean mode, the process proceeds to step S3.
In step 4, a feedback inhibition timer (time t) for the rotation speed for the compression lean mode is set. If it is determined in step S3 that the mode is not the compression lean mode, step S5
To set a feedback prohibition timer for the rotational speed other than the compression lean mode (for example, a feedback prohibition timer for the rotational speed for the intake stroke injection mode: time T).

The idling operation other than the compression lean mode may be, for example, a cold start. In this case, the stoichiometric feedback mode (see FIG. 2) is set. This is a timer for inhibiting the feedback of the rotational speed for the intake stroke injection mode.

After setting the timer in step S4 or S5, the process proceeds to step S6 in FIG. 6 to count down the timer. On the other hand, if it is determined in step S2 that the air conditioner switch 71 has not been turned on, the flow shifts to step S7 to prohibit the feedback of the rotation speed for the compression lean mode or the feedback of the rotation speed for the intake stroke injection mode. It is determined whether the timer is set. If it is determined that the timer has been set, the process proceeds to step S6 and the timer is counted down.

After counting down the timer in step S6, it is determined in step S8 whether the timer is 0 or not.
If it is determined in step S8 that the timer is 0, feedback of the rotation speed is permitted in step S9. If it is determined that the timer is not 0, feedback of the rotation speed is prohibited in step S9. On the other hand, step S7
When it is determined that the feedback prohibition timer for the rotation speed for the compression lean mode or the feedback prohibition timer for the rotation speed for the intake stroke injection mode is not set, the flow proceeds to step S9 to provide the feedback of the rotation speed. Ban.

That is, when an external load is applied during idling operation, for example, when the air conditioner switch 71 is turned on,
In the case of the compression lean mode, while the short time t during which the rotation speed is stabilized by the change in the fuel amount, which is set by the rotation speed feedback inhibition timer for the compression lean mode, elapses.
In the case of the intake stroke injection mode in which the feedback of the rotation speed is prohibited, the time T during which the rotation speed is stabilized by changing the air amount longer than the time t, which is set by the rotation speed feedback inhibition timer for the intake stroke injection mode, is set to T. During this time, the feedback of the rotation speed is prohibited.

For this reason, the period during which the feedback of the rotational speed is inhibited is different between when the external load is applied during the idling operation in the compression lean mode and when the external load is applied during the idling operation in the intake stroke injection mode. As a result, the responsiveness of the rotational speed feedback control in the compression lean mode is improved, and the stability of the feedback control in the intake stroke injection mode is ensured.

[0052]

According to the internal combustion engine of the present invention, the rotation speed is changed so that the actual rotation speed of the engine becomes a preset target rotation speed by changing at least the fuel amount in the compression stroke while changing the intake air amount in the intake stroke. The feedback control of the rotational speed when the external load is applied by the prohibition means for a predetermined period, and the setting means sets the predetermined period separately for the intake stroke and the compression stroke. The prohibition period of the feedback control in the compression lean mode in which the rotation speed is increased by changing the air-fuel ratio is shorter than the prohibition period of the feedback control in the intake stroke injection mode in which the rotation speed is increased by changing the intake air amount. Can be set. As a result, when performing the feedback control of the rotational speed, the stability of the feedback control in the intake stroke injection mode is secured, and the responsiveness of the feedback control in the compression lean mode is improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a multi-cylinder in-cylinder injection internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a fuel injection control map.

FIG. 3 is an explanatory diagram of a change over time in a compression lean mode.

FIG. 4 is a diagram illustrating a change over time in an intake stroke injection mode.

FIG. 5 is a flowchart of rotational speed feedback control during idling operation.

FIG. 6 is a flowchart of rotational speed feedback control during idling operation.

[Explanation of symbols]

 Reference Signs List 1 multi-cylinder in-cylinder injection internal combustion engine (in-cylinder injection engine) 2 cylinder head 4 fuel injection valve 5 combustion chamber 9 intake port 10 exhaust port 25 first air bypass valve 61 ECU 71 air conditioner switch

 ──────────────────────────────────────────────────の Continued on front page (72) Inventor Kazumasa Iida 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation

Claims (1)

[Claims] In an internal combustion engine in which fuel injection is performed at least in an intake stroke and a compression stroke, an intake air amount is changed in an intake stroke, while at least a fuel amount is changed in a compression stroke to set an actual rotational speed of the engine in advance. Control means for feedback-controlling the rotation speed so as to be the rotation speed is provided,
The control means includes a prohibition means for prohibiting feedback control of the rotational speed for a predetermined period when an external load is applied, and a setting means for separately setting the predetermined period in the prohibition means for the intake stroke and the compression stroke. An internal combustion engine characterized by the following.