JP2000320355A - Internal combustion engine controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly control a fuel injection amount in a wide operation range to improve fuel consumption and output by advancing an intake cam phase or retarding an exhaust cam phase, when it is determined that a fuel injection amount is a small flow rate in an idle operation time and a rotation fluctuation amount of a crank shaft is a prescribed value or higher. SOLUTION: In an idle operation time of an engine 3, an ECU 2 controls an intake air amount and a fuel injection amount of an injector 12, so that the number of engine revolutions Ne becomes a target number of idle revolutions and an air-fuel ratio of mixture becomes a target air-fuel ratio. In this case, when it is determined that a fuel injection amount in the idle operation is a small flow rate not more than a predetermined value and a rotation fluctuation amount ΔNe of a crank shaft 9 is a prescribed value or more, a cam phase variable mechanism 8 is driven by means of a solenoid control valve 10 for performing either of advancing control for advancing an intake cam phase, with respect to the crank shaft 9 or retarding control for retarding an exhaust can phase with respect to the crank shaft 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly to a control device capable of appropriately supplying fuel by an injector during idling operation.

[0002]

2. Description of the Related Art As a conventional control device for an internal combustion engine,
For example, one disclosed in Japanese Patent Publication No. 7-111167 is known. The internal combustion engine includes a lift control cam for switching a lift amount of an intake valve in a stepwise manner, a cam control shaft connected to the lift control cam, and an actuator that rotationally drives the lift control cam via the cam control shaft. And Five cam surfaces having different heights are formed on the outer peripheral surface of the lift control cam, and one of the cam surfaces is configured to selectively abut on a lever that supports the rocker arm, and the cam surface is provided with the cam surface. The lift amount of the intake valve can be switched stepwise by switching the surface by an actuator and positioning the rocker arm in contact with the intake cam at a different position.

In this control device, it is determined which of the five operating ranges of the engine from the idling operation state to the high-speed operation state is based on the throttle valve opening and the engine speed. The cam surface of the lift control cam is switched in accordance with the operation area to control the lift amount of the intake valve, and the fuel injection amount of the injector is controlled to obtain an output corresponding to the operation state of the engine. .

[0004]

However, the above-described conventional control device merely controls the lift amount of the intake valve in accordance with the operating state of the engine. At the time of idling operation or high-power operation, there is a problem that the fuel amount corresponding to the operation state cannot be appropriately supplied.

That is, in the above-mentioned conventional control device,
The lift amount of the intake valve, that is, the intake air amount, is simply increased or decreased according to the operating state of the engine.If combustion is attempted at the stoichiometric air-fuel ratio, the fuel supply amount also depends on the increased or decreased intake air amount. Simply increase or decrease. On the other hand, recent engines often require not only high output but also low fuel consumption at the same time, and the low friction of the engine is being promoted to improve fuel consumption. It tends to decrease, and the range of the fuel injection amount required for the injector tends to expand toward the low flow rate side.

However, the injection performance of the injector is physically limited, and the range of the flow rate that can be injected by one injector is limited. For this reason, when an injector with a low flow rate is employed to obtain a low output during idling operation, there is a problem that a required output cannot be obtained due to a shortage of fuel supply at a high output. Conversely, if a high flow rate injector is employed to ensure high output, the minimum guaranteed flow rate may exceed the required fuel amount during idle operation. In particular, when vapor (evaporated fuel) is supplied to the intake system by the vapor processing device, or when the atmospheric pressure of the fuel supply amount is corrected at high altitudes, the required fuel amount is further reduced, and the required fuel amount is reduced below the minimum guaranteed flow rate. Therefore, there is a possibility of causing a misfire or deterioration of fuel efficiency.

[0007] The present invention has been made to solve such a problem, and a single injector can appropriately supply fuel in a wide operating range from idle operation to high-power operation. An object of the present invention is to provide a control device for an internal combustion engine that can achieve both improvement in fuel efficiency and securing high output.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, at least one of an intake cam and an exhaust cam for opening and closing an intake valve 4 and an exhaust valve 5, respectively, has a crankshaft. The shaft 9 can be changed so that the engine speed Ne becomes the target idle speed NeOBJ during the idling operation, and the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 3 becomes the target air-fuel ratio. A control device for an internal combustion engine that controls the intake air amount and the fuel injection amount of the injector 12 (the fuel injection time TOUT in the embodiment (hereinafter the same in this section)). The fluctuation amount △ Ne is a predetermined amount △ NeNG
Crank fluctuation determining means (E
CU2, crank angle sensor 25), the fuel injection amount during idling is a small flow rate equal to or less than a predetermined value TOUTmin + α, and the rotation fluctuation amount 手段
When Ne is determined to be equal to or greater than the predetermined amount △ NeNG, advance control for advancing the phase of the intake cam with respect to the crankshaft 9 and retard control for retarding the phase of the exhaust cam with respect to the crankshaft 9 And a cam phase control means (ECU2) for performing at least one of the following.

According to the control apparatus for an internal combustion engine, during idling operation, the intake air amount and the fuel of the injector are adjusted such that the engine speed becomes the target idle speed and the air-fuel ratio becomes the target air-fuel ratio, for example, the stoichiometric air-fuel ratio. The injection amount is controlled. Also, during idling operation, when the fuel injection amount of the injector is a small flow rate equal to or less than a predetermined value and the crank fluctuation determining means determines that the rotational fluctuation amount of the crankshaft is equal to or more than the predetermined amount, the cam phase control means determines the intake air amount. Advancing control for advancing a phase of an intake cam that opens and closes a valve (hereinafter referred to as an “intake cam phase”) with respect to a crankshaft, and / or a phase of an exhaust cam that opens and closes an exhaust valve (hereinafter referred to as an “exhaust cam phase”) ) Is retarded with respect to the crankshaft. Due to the advance of the intake cam phase and / or the retardation of the exhaust cam phase, the overlap period between the opening of the intake valve and the exhaust valve becomes longer, the internal EGR increases, and the combustion efficiency decreases. Then, the engine speed tends to decrease. When this decrease in engine speed occurs, the intake air amount increases to compensate for this, and the fuel injection amount of the injector also increases accordingly, so that the engine speed increases to match the target idle speed. By reducing the rotation fluctuation amount, misfire is prevented, and the air-fuel ratio is maintained at a value near the target air-fuel ratio.

As described above, in the control device of the present invention, the fuel injection amount of the injector is reduced to a small flow rate equal to or less than the predetermined value during idling operation due to vapor supply to the intake system and atmospheric pressure correction. Then, when the amount of rotation fluctuation of the crankshaft becomes equal to or more than a predetermined amount, by performing advance control of the intake cam phase and / or retard control of the exhaust cam phase,
The required fuel amount is forcibly increased. Therefore, by setting the predetermined value of the fuel injection amount to an appropriate value slightly larger than the minimum guaranteed flow rate of the injector, the fuel injection amount of the injector during idling operation can be maintained at or above the minimum guaranteed flow rate. As a result, for example, by using one injector with a high flow rate, it is possible to appropriately supply fuel in a wide operation range from idling operation to high output operation, thereby achieving both improvement in fuel efficiency and securing high output. Can be. In addition, since the fuel injection amount is increased by advancing the intake cam phase while checking the actual rotation fluctuation amount of the crankshaft, misfire can be reliably prevented,
An increase in the fuel supply amount can be suppressed to a minimum, and idle stability during idling is also improved.

Further, according to the invention, at least one phase of an intake cam and an exhaust cam for opening and closing the intake valve 4 and the exhaust valve 5, respectively, can be changed with respect to the crankshaft 9, and the intake system (intake pipe) 11) so that vapor can be supplied to the engine, and the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 3 becomes the target air-fuel ratio so that the engine speed Ne becomes the target idle speed NeOBJ during idling operation. In addition, the intake air amount and the injector 1
2. A control device for an internal combustion engine for performing feedback control of the fuel injection amount (fuel injection time TOUT) of No. 2, wherein a vapor concentration detecting means (ECU2) for detecting a concentration of vapor;
Crank fluctuation determining means (ECU2, crank angle sensor 25) for determining whether or not the rotational fluctuation amount ΔNe of the crankshaft 9 during idling is equal to or greater than a predetermined amount ΔNeNG; When the flow rate is smaller than the value TOUTmin + α and the rotation fluctuation amount ΔNe is equal to or larger than a predetermined amount
When it is determined to be G, the phase of the intake cam is advanced with respect to the crankshaft 9 in accordance with the vapor density detected by the vapor density detection means, and the phase of the exhaust cam is changed to the crankshaft 9. Phase control means (ECU for performing at least one of retard control for retarding the
2) are provided.

According to this control device, the above-described operation of the control device according to the first aspect can be similarly obtained. That is, during idling operation, when the fuel injection amount of the injector decreases to a small flow rate equal to or less than a predetermined value and the amount of rotation fluctuation of the crankshaft becomes equal to or more than the predetermined amount, the advance control of the intake cam phase and / or the exhaust cam By executing the phase retard control to increase the required fuel amount, one injector can appropriately supply fuel in a wide operating range from idle operation to high output operation, thereby improving fuel efficiency and improving fuel efficiency. High output can be ensured at the same time. In addition to this, the control device executes the advance control of the intake cam phase and / or the retard control of the exhaust cam phase in accordance with the vapor concentration detected by the vapor concentration detecting means.
The required fuel amount can be appropriately increased according to the actual vapor concentration, and misfire caused by vapor supply can be reliably prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a control device for an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a control device 1 for an internal combustion engine according to the present embodiment. As shown in FIG. 1, the control device 1 includes an ECU (cam phase control means) 2. The ECU 2 is operated in accordance with an operating state of an internal combustion engine (hereinafter, simply referred to as “engine”) 3 to be described later. The fuel supply control and the cam phase control are performed as described below.

The engine 3 is a four-stroke DOHC type gasoline engine, and has an intake valve 4 and an exhaust valve 5 during operation.
Camshaft 6 integrally provided with a plurality of intake cams and exhaust cams (both not shown) for respectively driving the opening and closing of
And an exhaust camshaft 7. At one end of each of the intake camshaft 6 and the exhaust camshaft 7, variable cam phase mechanisms 8, 8 (only those for the intake cam are shown) are provided.

Each of the variable cam phase mechanisms 8 is driven by hydraulic pressure, and one of the cam phase variable mechanisms 8 for the intake cam is a phase of the intake camshaft 6 with respect to the crankshaft 9 and the phase of the intake cam integrated therewith (hereinafter, simply referred to as a “camera”). "Intake cam phase"
) Is advanced or retarded steplessly to advance or retard the opening / closing timing of the intake valve. Similarly, the variable cam phase mechanism 8 for the exhaust cam is provided with a phase of the exhaust camshaft 7 with respect to the crankshaft 9 and the phase of the exhaust cam integrated therewith (hereinafter simply referred to as “exhaust cam phase”).
) Is advanced or retarded in a stepless manner, whereby the opening / closing timing of the exhaust valve is advanced or retarded.

Each of the variable cam phase mechanisms 8 includes an electromagnetic control valve 1
0 (only the one for the intake cam is shown) is connected. The intake cam electromagnetic control valve 10 is driven by a drive signal CAIN composed of a duty signal from the ECU 2, and according to the duty ratio, the hydraulic pressure from a lubrication system hydraulic pump (not shown) of the engine 3 is cammed. It is supplied to the variable phase mechanism 8. As described above, the ECU 2 controls the electromagnetic control valve 1
By controlling the cam phase variable mechanism 8 via
Advance or retard the intake cam phase. Although not shown, the ECU 2 also controls the electromagnetic control valve 10 for the exhaust cam.
Output a similar drive signal to advance or retard the exhaust cam phase.

Further, the ends of the intake camshaft 6 and the exhaust camshaft 7 on the side opposite to the cam phase varying mechanism 8 are provided with:
Cam phase sensors 20, 20 (only those for the intake cam are shown) are provided. These cam phase sensors 20, 20 are, for example, a magnet rotor and an MRE.
The ECU 2 detects a phase of an intake cam and a phase of an exhaust cam, and outputs a detection signal to the ECU 2.
Output to Further, the cam phase sensor 20 outputs a TDC signal which is a pulse signal. This TDC signal is a signal indicating that the piston of the engine 3 is near the top dead center at the start of the intake stroke in each cylinder, and is output as one pulse every predetermined angle (for example, 45 degrees) of the intake camshaft 6. .

A throttle valve 15 is provided in the intake pipe 11 of the engine 3. The throttle valve opening θTH is detected by a throttle valve opening sensor 28, and a detection signal is sent to the ECU 2. Further, on the downstream side of the throttle valve 15 of the intake pipe 11, an injector 12, an intake air temperature sensor 16 composed of a thermistor and the like, and an intake pressure sensor 21 composed of a semiconductor pressure sensor and the like are attached. The injector 12 responds to a drive signal from the ECU 2 by a fuel injection time (fuel injection amount) TOUT.
Is controlled, and fuel is injected and supplied into the intake pipe 11. The intake air temperature sensor 16 detects the intake air temperature TA, which is the temperature of the intake air in the intake pipe 11, and the intake pressure sensor 21 detects the absolute pressure PBA in the intake pipe 11, respectively.
Send to CU2.

A secondary intake passage 29 bypassing the throttle valve 15 is provided in the intake pipe 11, and a secondary intake control valve 30 is provided in the middle of the secondary intake passage 29, so that the idle intake operation By controlling the opening degree of the secondary intake control valve 30 with a control signal output from the ECU 2 and controlling the amount of secondary air passing through the secondary intake passage 29, the engine rotational speed Ne becomes equal to the target idle rotational speed. It is controlled to be NeOBJ. Further, a canister (not shown) that adsorbs vapor (evaporated fuel) generated in the fuel tank is connected to the intake pipe 11 downstream of the throttle valve 15 via a passage 17. A purge control valve 18 is provided on the way. Purge control valve 18
Is connected to the ECU 2 and supplies (purges) the vapor stored in the canister to the intake pipe 11 when the valve is opened by the ECU 2 in a predetermined operation state.

In the middle of an exhaust pipe 13 of the engine 3, a three-way catalyst 1 for purifying HC, CO, NOx and the like in exhaust gas is provided.
4 are arranged. On the upstream side of the three-way catalyst 14, an LAF sensor 2 composed of zirconia and platinum electrodes, etc.
2 are provided. The LAF sensor 22 detects the oxygen concentration in the exhaust gas and sends a detection signal proportional to the oxygen concentration to the ECU 2.

Further, the main body of the engine 3 is provided with a water temperature sensor 23 and an oil temperature sensor 2 composed of a thermistor or the like.
4 is attached. The water temperature sensor 23 detects the engine water temperature TW, which is the temperature of the cooling water circulating in the cylinder block of the engine 3, and the oil temperature sensor 24 detects the oil temperature TOIL, which is the oil temperature of the lubrication system of the engine 3, respectively. These detection signals are sent to the ECU 2. Also, ECU
2, a signal indicating the atmospheric pressure PA detected by the atmospheric pressure sensor 26 is sent.

The engine 3 is provided with a crank angle sensor 25. The crank angle sensor 25 is a combination of a magnet rotor and an MRE pickup, and is a pulse signal C at every predetermined crank angle (for example, 1 °) as the crankshaft 9 rotates.
An RK signal is output to the ECU 2. The ECU 2 uses this CR
Based on the K signal, the engine speed Ne of the engine 3 and the rotation fluctuation amount △ Ne of the crankshaft 9 are obtained.

The ECU 2 has an I / O interface 2
a, a CPU 2b, a RAM 2c, a ROM 2d, and the like.
The M2c uses a backup power supply to hold the stored data even when the engine 3 is stopped. The detection signals from the various sensors described above are subjected to A / D conversion and shaping by the I / O interface 2a, respectively.
It is input to the CPU 2b.

The CPU 2b determines an operation state of the engine 3 such as an idle operation area or a high output operation area in accordance with these input signals. Further, in accordance with the determined operating state, a control program or the like stored in the ROM 2d or RA
The fuel supply amount is controlled by calculating the fuel injection time TOUT of the injector 12 according to the data stored in the M2c and outputting a drive signal to the injector 12 based on the calculation result. For example, when it is determined that the engine 3 is in the idling operation state, the engine speed Ne at that time is set to the target idle speed NeOBJ, and the air-fuel ratio of the mixture supplied to the engine 3 is stoichiometric. In principle, feedback control of the secondary air amount by the secondary intake control valve 30 and feedback control of the fuel injection time TOUT according to the oxygen concentration detected by the LAF sensor 22 are performed so as to obtain the fuel ratio. Further, the CPU 2b calculates the intake cam phase CAIN as described below, and controls the intake cam phase CAIN by outputting a drive signal based on the calculation result to the electromagnetic control valve 10.

FIG. 2 is a flowchart of a process for calculating the intake cam phase CAIN. In this process, first,
In step 1 (illustrated as "S1"; the same applies hereinafter), it is determined whether or not the engine 3 is idling. This determination is made, for example, by the throttle valve opening sensor 28.
Is performed based on whether or not the throttle valve opening θTH detected at step S is equal to or less than a predetermined opening and the engine speed Ne is equal to or less than a predetermined speed. When the number Ne is equal to or less than the predetermined rotation speed, it is determined that the engine is idling. When it is determined that the vehicle is not idling, the program ends.

On the other hand, when it is determined in step 1 that the engine 3 is idling, the fuel injection time TOUT calculated by the CPU 2b is reduced to a predetermined value (TOUTmin +
α) It is determined whether it is equal to or less than (step 2). Here, TOUTmin indicates the minimum fuel injection time corresponding to the minimum guaranteed flow rate of the injector 12, and the value α is a constant set as a margin. If the answer to step 2 is YES,
That is, when TOUT ≦ TOUTmin + α is satisfied, it is determined that the injector 12 is in a small flow rate state close to the minimum guaranteed flow rate, and the process proceeds to step 3.

In step 3, it is determined whether or not the feedback control of the air-fuel ratio is being performed. When the feedback control is being performed, the rotational fluctuation amount of the crankshaft 9 △ Ne
Is greater than or equal to a predetermined amount △ NeNG (step 4). As shown in FIG. 3, the predetermined amount △ NeNG has an upper limit value △ NeNGLIMH and a lower limit value △ NeNG.
This is provided with hysteresis composed of LIML, and is set as a lower value that takes a predetermined safety factor against the amount of rotation fluctuation that can cause misfire.

If the answer to step 4 is YES, that is, △
If Ne ≧ △ NeNG, a basic advance amount △ CAINB of the intake cam phase CAIN is obtained according to the target idle speed NeOBJ at that time (step 5). The basic advance amount △ CAINB is obtained by searching a table (not shown) stored in the ROM 2d.

Next, a vapor concentration correction coefficient CAINVAP is determined according to the vapor concentration supplied from the canister (step 6). Specifically, the air-fuel ratio correction coefficient KLAF obtained during the feedback control of the air-fuel ratio is determined when the vapor is purged (when the vapor control valve 18 is opened) and when the vapor is not purged (when the vapor control valve 18 is closed). When the difference between the two learning values is equal to or larger than a predetermined value, it is determined that the purging is in effect so as to affect the air-fuel ratio, and the vapor concentration correction coefficient CAINVAP is stored in a table (not shown) stored in the ROM 2d. ) By searching. In this table, the larger the difference between the two learning values, that is, the higher the vapor density, the more the vapor density correction coefficient CAIN
VAP is set to a larger value. With such a setting, the amount of intake air corresponding to the air-fuel ratio rich state accompanying the vapor supply is increased by the secondary air controlled by the secondary intake control valve 30, so that the air-fuel ratio becomes close to the stoichiometric air-fuel ratio. Can be set to

Next, by searching a table (not shown) stored in the ROM 2d according to the atmospheric pressure PA detected by the atmospheric pressure sensor 26, an atmospheric pressure correction coefficient CA
The INPA is obtained (step 7). The atmospheric pressure correction coefficient CAINPA and the vapor concentration correction coefficient CA
INVAP is set as a variable of 1.0 or more. Next, the basic advance amount △ CAINB, the vapor concentration correction coefficient CAINVAP, and the atmospheric pressure correction coefficient CAINPA obtained in steps 7 to 9 are multiplied by each other to obtain an advance amount △ CAIN (= △ CAINB × CAINVAP × CA).
INPA) is calculated (step 8), and the calculated advance amount △ CAIN is added to the previous intake cam phase CAINn-1 to obtain the current intake cam phase CAINn (= CAINn-1).
+ △ CAIN) (step 9), and the intake cam phase CA
IN is advanced by $ CAIN. Then, step 9
A limit check of the intake cam phase CAINn calculated in (1) is performed (step 10), and the program is terminated.

On the other hand, if any one of the above-mentioned steps 2 to 4 is NO, that is, the fuel injection time TOUT> TOU
When Tmin + α, when the air-fuel ratio feedback control is not being performed, or when △ Ne <△ NeNG, the intake cam phase CAIN is not advanced, and is held at the previous value CAINn−1 (step 11). To end.

FIG. 3 shows the fuel injection time TOUT during the idling operation and the intake cam phase C obtained by the above control.
5 shows an example of transition of the AIN and the rotation fluctuation amount ΔNe of the crankshaft 9. In the figure, first, at time t1
Previously, the fuel injection time TOUT was equal to the predetermined value TOU
Tmin + α or more and the rotational fluctuation amount △ Ne
Is considerably smaller than the predetermined amount △ NeNG, the engine 3 is in a relatively stable rotation state, and the intake cam phase CAIN is set to its initial value CAINo.

From this state, when the supply of vapor to the intake system and the correction of the atmospheric pressure are executed, the fuel injection time TOUT is gradually reduced by the feedback control of the air-fuel ratio, and becomes equal to or less than the predetermined value TOUTmin + α at time t1 (FIG. Step 2 of 2: YES). Thereafter, as the fuel injection time TOUT continues to decrease gradually, the rotation fluctuation amount △ Ne becomes equal to or greater than the predetermined amount 上限 NeNG upper limit value ＮNeNGLIMH (time t2).
When the answer to step 4 is YES, steps 5-1
0 is executed, and the intake cam phase CAIN becomes the advance amount 角 CAI
It is advanced by N. Due to the advance of the intake cam phase CAIN, the overlap period of the opening of the intake valve 4 and the exhaust valve 5 becomes longer, the internal EGR increases, and the combustion efficiency decreases. As a result, the torque decreases, and the engine speed N increases.
e tends to decrease. When the engine speed Ne decreases, the secondary air amount increases by controlling the secondary intake control valve 30 to compensate for the decrease, so that the intake air amount increases, and accordingly, the fuel injection time TOUT also increases. I do.
As a result, the fuel injection time TOUT is reduced by the injector 12
Fuel injection time TOUTm corresponding to the minimum guaranteed flow rate of
By maintaining the air-fuel ratio at a value in the vicinity of the target air-fuel ratio while maintaining the value at or above in, the crank rotation fluctuation is suppressed, and stable idle operation is achieved.

When the rotation fluctuation amount Ne becomes equal to or less than the predetermined amount NeNe lower limit value NeNGLIML at time t3 (step 4: NO), step 11 is executed, and the advance of the intake cam phase CAIN is stopped. . Thus, the engine 3 is prevented from misfiring by keeping the rotation fluctuation amount △ Ne at or below the value in the vicinity of the predetermined amount ＮNeNG.

As described above, according to the present embodiment, the fuel injection amount TOUT of the injector 12 is reduced to the predetermined value T during the idling operation due to the supply of vapor and the correction of the atmospheric pressure.
The fuel injection time TOUT is compulsorily controlled by performing the advance control of the intake cam phase CAIN when the rotation flow amount ΔNe of the crankshaft 9 becomes equal to or more than the predetermined amount し NeNG when the flow rate is reduced to a small flow rate equal to or less than OUTmin + α. To a value equal to or longer than the minimum fuel injection time TOUTmin corresponding to the minimum guaranteed flow rate of the injector 12. as a result,
For example, by using one injector 12 with a high flow rate, it is possible to appropriately supply fuel in a wide operation range from idling operation to high output operation, thereby achieving both improvement in fuel efficiency and securing high output. . In addition, the fuel injection time TOUT is increased by advancing the intake cam phase CAIN while observing the actual rotation fluctuation amount △ Ne of the crankshaft 9, so that misfire can be reliably prevented and the fuel supply amount can be increased. It can be minimized.

A vapor concentration correction coefficient CAINVAP set in accordance with the vapor concentration and the atmospheric pressure PA, respectively.
And the atmospheric pressure correction coefficient CAINPA is used to set the advance angle △ CAIN of the intake cam phase CAIN, so that the fuel injection time TOUT is set to the actual vapor concentration and the atmospheric pressure PA.
, And misfires caused by vapor supply and atmospheric pressure correction can be reliably prevented.

The description so far is based on the intake cam phase C
This is an example of the case where the AIN advance angle control is performed. However, when the exhaust cam phase retarding control is performed by the exhaust cam variable cam mechanism 8, △ CAINB in step 5 of FIG. Is set. Further, when the advance control of the intake cam phase and the retard control of the exhaust cam phase are performed simultaneously, the above-described effect can be obtained more favorably.

[0038]

As described above, the control device for an internal combustion engine according to the present invention can appropriately supply fuel from the injector in a wide operating range from idling operation to high output operation, thereby improving fuel efficiency. This has the effect of ensuring high output at the same time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a control device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a control process by the control device of FIG. 1;

FIG. 3 is a time chart illustrating an operation example according to the flowchart of FIG. 2;

[Explanation of symbols]

Reference Signs List 1 control device 2 ECU (cam phase control means, crank fluctuation determination means, vapor concentration detection means) 3 internal combustion engine 4 intake valve 5 exhaust valve 6 intake camshaft 7 exhaust camshaft 8 variable cam phase mechanism 9 crankshaft 11 intake pipe ( Intake system 12 Injector 18 Purge control valve 25 Crank angle sensor (Crank variation determination means) Ne Engine speed NeOBJ Target idle speed △ Ne Crankshaft rotation variation TOUT Fuel injection time (fuel injection amount)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 41/14 310 F02D 41/14 310P 330 330D 41/16 41/16 P 43/00 301 43/00 301E 301Z 301M 45/00 312 45/00 312B 362 362J F02M 25/08 301 F02M 25/08 301J F-term (reference) 3G016 AA02 AA08 AA19 BA02 BA05 BA26 BA38 DA06 3G084 BA03 BA04 BA09 BA13 BA23 CA03 DA01 DA02 FA01 FA02 FA07 FA07 FA20 FA34 FA38 3G092 AA01 AA11 AA19 AB02 BA01 BA04 BB01 DA01 DA02 DA09 DC04 DG05 DG09 EA02 EA03 EA04 EA09 EA13 EA22 EC08 FA01 FA21 FA24 FA40 GA04 HA01X HA01Z HA04Z HA05Z HA06Z HA10X HA13X HA13Z HA13X HA13X HA13X HA13X HA13Z HABZ LA01 LA04 LA07 LB03 LC01 LC08 MA01 MA11 ND41 NE08 NE11 NE12 NE16 NE19 PA01A PA01Z PA07Z PA09Z PA10Z PA11Z PB03A PB09Z PE02Z PE03Z PE08Z PE10A PE10Z

Claims (2)

[Claims] At least one phase of an intake cam and an exhaust cam for opening and closing an intake valve and an exhaust valve, respectively, is configured to be changeable with respect to a crankshaft.
An internal combustion engine that controls an intake air amount and a fuel injection amount of an injector so that an engine speed becomes a target idle speed during idling operation and an air-fuel ratio of a mixture supplied to the internal combustion engine becomes a target air-fuel ratio. A crank fluctuation determining means for determining whether or not a rotational fluctuation amount of the crankshaft during idling operation is equal to or more than a predetermined amount; and a small fuel injection amount during idling operation being equal to or less than a predetermined value. An advance angle control for advancing the phase of the intake cam with respect to the crankshaft when the rotation fluctuation amount is determined to be equal to or greater than the predetermined amount by the crank fluctuation determination means; Cam phase control means for performing at least one of retard control for retarding the phase with respect to the crankshaft. Control system for an internal combustion engine characterized by. 2. The phase of at least one of an intake cam and an exhaust cam that opens and closes an intake valve and an exhaust valve, respectively, can be changed with respect to a crankshaft, and vapor can be supplied to an intake system. Control of the internal combustion engine that performs feedback control of the intake air amount and the fuel injection amount of the injector so that the engine speed becomes the target idle speed and the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine becomes the target air-fuel ratio. A vapor concentration detecting means for detecting a concentration of the vapor; a crank fluctuation determining means for determining whether or not a rotation fluctuation amount of the crankshaft during idling operation is equal to or more than a predetermined amount; The fuel injection amount at a small flow rate equal to or less than a predetermined value, and the crank fluctuation determining means An advance angle control for advancing the phase of the intake cam with respect to the crankshaft in accordance with the concentration of the vapor detected by the vapor concentration detecting means when the variation amount is determined to be equal to or greater than the predetermined amount; And a cam phase control means for performing at least one of retard control for retarding the phase of the exhaust cam with respect to the crankshaft.