JP2001254644A - Internal combustion engine having an electromagnetically driven valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of early starting the internal combustion engine while restraining discharge of HC. SOLUTION: Fuel is injected into an optional cylinder 21 the piston of which is at the bottom dead center or in a compression stroke from the bottom dead center at the time of detection after a piston position of each of the cylinders 21 is detected in starting of an internal combustion engine 1 having solenoid driving valve. A means to open an air intake valve 28 of the optional cylinder 21 according to fuel injection to supply fuel from an injector 32a arranged in an air intake pipe out of the cylinder and to inject fuel when the above piston position is at the bottom dead center or in the compression stroke from the bottom dead center is furnished.

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 having an electromagnetically driven valve, and more particularly, to an engine that can be started early.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No.
BACKGROUND ART As disclosed in 195736, those configured as exhaust valves or intake valves of internal combustion engines are known. Such an electromagnetically driven valve is composed of an armature made of a ferromagnetic material and moving forward and backward in conjunction with an intake / exhaust valve, a valve closing electromagnet for attracting the armature in a valve closing direction when an excitation current is applied, and an excitation A valve-opening electromagnet that attracts the armature in the valve-opening direction when a current is applied, a valve-closing-side return spring that urges the armature in the valve-closing direction, and an opening that urges the armature in the valve-opening direction A device provided with a valve-side return spring is known.

According to such an electromagnetically driven valve, there is no need to open and close the intake / exhaust valve in conjunction with the rotation of the engine output shaft unlike the conventional valve operating mechanism. It is possible to open and close the intake / exhaust valve at any time by changing the application timing of the excitation current to the intake air.

In a normal internal combustion engine, in order to determine the fuel injection timing at the time of starting, the fuel injection is started after determining the piston position in the cylinder and the opening / closing timing of the intake / exhaust valve for each cylinder. However, in this case, a relatively long starting time is required. That is, for example, the cylinder position sensor determines which cylinder is at the top dead center, and the cam position sensor detects the position of the cam during 720 ° CA to determine the opening / closing timing of the intake / exhaust valve. The cylinder discrimination is completed while the crankshaft rotates at a maximum of 720 °, and fuel injection and ignition become possible.

[0005]

In order to start the internal combustion engine early, there is a method of simultaneously injecting fuel into all the cylinders at the time of starting without performing the above-described cylinder discrimination. In such a case, unburned raw gas is discharged as it is, and a large amount of HC is present in the exhaust gas, resulting in deterioration of emission.

On the other hand, in the electromagnetically driven valve, as described above, the opening / closing timing of the intake / exhaust valve can be arbitrarily changed based on the piston position, so that the fuel may be injected earlier. That is, the electromagnetically driven valve can be started from any cylinder, and by synchronizing fuel injection and valve operation as necessary, early startability can be ensured and unnecessary HC emission can be prevented.

The present invention has been made in view of such a point, and it is an object of the present invention to provide an internal combustion engine that can start the internal combustion engine early while suppressing the emission of HC.

[0008]

The present invention has the following configuration to achieve the above object. In an internal combustion engine having an electromagnetically driven valve, after detecting the piston position of each cylinder at the time of starting the internal combustion engine, the piston injects fuel into the bottom dead center and any cylinder in a compression stroke from the bottom dead center at the time of this detection. It is characterized by.

In the present invention, fuel is supplied from an injector installed in an intake pipe outside the cylinder, and the piston is located at the bottom dead center and in a compression stroke from the bottom dead center. The valve may be provided with means for opening the valve with fuel injection.

[0010] In the internal combustion engine provided with such an electromagnetically driven valve, after the cylinder discrimination for the fuel injection is completed, 18
It is easy to ignite at 0 ° CA. In a so-called direct injection type internal combustion engine that supplies fuel directly into a cylinder, fuel can be injected even during the compression stroke, and the fuel injection does not need to be accompanied by opening and closing of an intake valve.

In the present invention, the piston position can be detected by a crank position sensor. It is assumed that one cylinder whose piston is detected as being at the top dead center is in the exhaust stroke, and starting is started. At that time, any cylinder at the bottom dead center is assumed to be in the compression stroke. That is, the position of the intake and exhaust valves can be freely set by the electromagnetically driven valve,
Cylinders with pistons at top dead center can always be started on exhaust stroke.

At this time, fuel is injected in the compression stroke in the cylinder at the bottom dead center or in the compression stroke from the bottom dead center. However, in the vicinity of the bottom dead center, even if the intake valve is opened, backflow of the intake air does not yet occur. Therefore, fuel can be supplied into the cylinder by the injection pressure of the injection even in the injection at the intake port with the opening and closing of the intake valve.

In cylinders other than the above, it is possible to minimize the discharge of HC and to secure the injection timing and valve opening timing at which reliable ignition can be obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of an internal combustion engine having an electromagnetically driven valve according to the present invention will be described below with reference to the drawings.

FIG. 1 is a side view showing a schematic configuration of an internal combustion engine having an electromagnetically driven valve according to the present invention, and FIG. 2 is a plan view thereof. The internal combustion engine 1 is a four-cycle gasoline engine including a plurality of cylinders 21 and a fuel injection valve 32 for injecting fuel into each cylinder 21 in an intake path.

The internal combustion engine 1 includes a cylinder block 1b in which a plurality of cylinders 21 and a cooling water passage 1c are formed, and a cylinder head 1a fixed on an upper portion of the cylinder block 1b.

A crankshaft 23 as an engine output shaft is rotatably supported on the cylinder block 1b.
The crankshaft 23 is connected to a piston 22 slidably mounted in each cylinder 21.

Above the piston 22, a piston 2
2 and a combustion chamber 24 surrounded by the wall surface of the cylinder head 1a. An ignition plug 25 is attached to the cylinder head 1a so as to face the combustion chamber 24.
An igniter 19 for applying a drive current to the ignition plug 25 is connected to the ignition plug 25.

In the cylinder head 1a, the open ends of two intake ports 26 and the open ends of two exhaust ports 27 are formed so as to face the combustion chamber 24. Each opening end of the intake port 26 is opened and closed by an intake valve 28 supported on the cylinder head 1a so as to be able to advance and retreat, and these intake valves 28 are electromagnetically driven valves 30 provided on the cylinder head 1a. (Hereinafter, referred to as an intake side electromagnetically driven valve 30).

Each open end of the exhaust port 27 is opened and closed by an exhaust valve 29 supported on the cylinder head 1a so as to be able to move forward and backward. These exhaust valves 29 are provided on the cylinder head 1a. Drive valve 31 (hereinafter, referred to as
It is opened and closed by an exhaust side electromagnetically driven valve 31).

Each intake port 26 of the internal combustion engine 1 communicates with each branch pipe of an intake branch pipe 33 attached to the cylinder head 1a of the internal combustion engine 1. The intake branch pipe 33
Is connected to a surge tank 34 for suppressing pulsation of intake air. The surge tank 34 has an intake pipe 35
Is connected, and the intake pipe 35 is connected to an air cleaner box 36 for removing dust, dust and the like in the intake air.

The intake pipe 35 is provided with an air flow meter 44 for outputting an electric signal corresponding to the mass of the air flowing through the intake pipe 35 (mass of intake air). In the intake pipe 35, the air flow meter 44
A throttle valve 39 for adjusting the flow rate of the intake air flowing through the intake pipe 35 is provided at a further downstream portion.

The throttle valve 39 is provided with a throttle actuator 40 comprising a stepper motor or the like for opening and closing the throttle valve 39 in accordance with the magnitude of the applied power.
A throttle position sensor 41 for outputting an electric signal corresponding to the opening of the throttle valve 39; and an accelerator pedal 42 mechanically connected to an accelerator pedal 42.
And an accelerator position sensor 43 that outputs an electric signal corresponding to the operation amount of the vehicle.

A vacuum sensor 50 for outputting an electric signal corresponding to the pressure of the surge tank 34 is attached to the surge tank 34. On the other hand, each exhaust port 27 of the internal combustion engine 1 communicates with each branch pipe of the exhaust branch pipe 45 attached to the cylinder head 1a.
The exhaust branch pipe 45 is connected to an exhaust pipe 47 via an exhaust purification catalyst 46, and the exhaust pipe 47 is connected downstream to a muffler (not shown).

The exhaust branch pipe 45 is provided with the exhaust branch pipe 45.
The air-fuel ratio of the exhaust flowing through the inside, in other words, the exhaust purification catalyst 4
An air-fuel ratio sensor 48 that outputs an electric signal corresponding to the air-fuel ratio of the exhaust gas flowing into the exhaust gas 6 is attached.

The internal combustion engine 1 has a crankshaft 23
The crank position sensor 51 includes a timing rotor 51a attached to the end of the cylinder and an electromagnetic pickup 51b attached to the cylinder block 1b near the timing rotor 51a. There are provided 34 teeth at intervals of 10 °, in which two of the teeth are cut out, and the crank position and the crank speed are detected.

Further, a starter motor 55 connected to a flywheel connected to a crankshaft, and a water temperature sensor 52 for detecting the temperature of cooling water flowing through a cooling water passage 1c formed inside the internal combustion engine 1 are provided. .

An electronic control unit (ECU) for controlling the operating state of the internal combustion engine 1 is provided in the internal combustion engine 1 configured as described above.
20).

The ECU 20 includes a throttle position sensor 41, an accelerator position sensor 43, an air flow meter 44, an air-fuel ratio sensor 48, and a catalyst temperature sensor 4.
9, various sensors such as a vacuum sensor 50, a crank position sensor 51, and a water temperature sensor 52 are connected via electric wiring, and output signals of the sensors are input to the ECU 20.

The ECU 20 is connected with an igniter 19, an intake side electromagnetically driven valve 30, an exhaust side electromagnetically driven valve 31, a fuel injection valve 32, and the like via electric wiring. The ECU 20 uses output signal values of various sensors as parameters. Igniter 1
9. The intake-side electromagnetic drive valve 30, the exhaust-side electromagnetic drive valve 31, and the fuel injection valve 32 can be controlled.

Here, as shown in FIG. 3, the ECU 20 controls the CPs connected to each other by a bidirectional bus 400.
It includes a U 401, a ROM 402, a RAM 403, a backup RAM 404, an external input circuit 405, and an external output circuit 406.

The external input circuit 405 inputs the output signals of a sensor such as the crank position sensor 51 that outputs a digital signal, and transmits those output signals to the CPU 401 or the RAM 403.

The external input circuit 405 includes a throttle position sensor 41, an accelerator position sensor 43,
Output signals of sensors that output signals in analog signal format, such as an air flow meter 44, an air-fuel ratio sensor 48, a catalyst temperature sensor 49, a vacuum sensor 50, and a water temperature sensor 52, are input to the CPU 401 and RAM.
Send to 403.

The external output circuit 406 is connected to the CPU 4
The control signals output from the ECU 01 are supplied to the igniter 19, the intake side electromagnetically driven valve 30, the exhaust side electromagnetically driven valve 31, and the fuel injection valve 3.
Send to 2.

The ROM 402 includes a fuel injection amount control routine for determining the fuel injection amount, a fuel injection timing control routine for determining the fuel injection timing, and the opening of the intake valve for determining the opening timing of the intake valve 28. Valve timing control routine,
Exhaust valve opening timing control routine for determining the valve opening timing of the exhaust valve 29, ignition timing control routine for determining the ignition timing of the spark plug 25 of each cylinder 21, throttle valve 39
Excitation current control routine for determining the amount of excitation current to be applied to the intake-side electromagnetic drive valve 30 and the exhaust-side electromagnetic drive valve 31 in addition to an application program such as a throttle opening control routine for determining the opening of the vehicle. I remember.

The ROM 402 stores various control maps in addition to the above-described application programs. The control map includes, for example, a fuel injection amount control map indicating a relationship between the operating state of the internal combustion engine 1 and the fuel injection amount, a fuel injection timing control map indicating a relationship between the operating state of the internal combustion engine 1 and the fuel injection timing, An intake valve opening / closing timing control map showing the relationship between the operating state of the internal combustion engine 1 and the opening / closing timing of the intake valve 28, an exhaust valve opening / closing timing control map showing the relationship between the operating state of the internal combustion engine 1 and the opening / closing timing of the exhaust valve 29, Internal combustion engine 1
Current control map showing the relationship between the operating state of the internal combustion engine and the amount of exciting current to be applied to the intake side electromagnetically driven valve 30 and the exhaust side electromagnetically driven valve 31, the operating state of the internal combustion engine 1 and the ignition timing of each spark plug 25. And a throttle opening control map indicating the relationship between the operating state of the internal combustion engine 1 and the opening of the throttle valve 39.

The RAM 403 stores an output signal of each sensor, a calculation result of the CPU 401, and the like. The calculation result is, for example, an engine speed calculated based on an output signal of the crank position sensor 51. The RAM
The various data stored in 403 is rewritten to the latest data every time the crank position sensor 51 outputs a signal.

The backup RAM 404 is a non-volatile memory that retains data even after the operation of the internal combustion engine 1 is stopped, and stores learning values related to various controls. The CP
The U401 operates based on the application program stored in the ROM 402, and executes the exciting current amount control which is the gist of the present invention, in addition to the fuel injection control, the intake valve opening / closing control, the exhaust valve opening / closing control, the ignition control, and the like. .

Next, a specific configuration of the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 will be described. In addition,
Since the intake-side electromagnetic drive mechanism 30 and the exhaust-side electromagnetic drive mechanism 31 have the same configuration, only the intake-side electromagnetic drive mechanism 30 will be described as an example.

FIG. 3 is a sectional view showing the structure of the intake side electromagnetically driven valve 30. In the drawing, a cylinder head 1a of an internal combustion engine 1 includes a lower head 10 fixed to an upper surface of a cylinder block 1b, and an upper head 11 provided above the lower head 10.

An intake port 26 corresponding to each cylinder 21 is formed in the lower head 10, and a valve seat 12 on which a valve body 28 a of an intake valve 28 is seated is provided at an open end of each intake port 26 on the combustion chamber 24 side. Is provided.

The lower head 10 is formed with a through-hole having a circular cross section from the inner wall surface of each intake port 26 to the upper surface of the lower head 10. The through-hole has a valve stem of an intake valve 28 inserted into the through-hole. A cylindrical valve guide 13 that guides 28b to be able to move forward and backward is inserted.

The upper head 11 has a core mounting hole 1 having a circular cross section into which the first core 301 and the second core 302 are fitted.
The core mounting hole 14 is located at a position where the axis of the core is the same as that of the valve guide 13. Core mounting hole 1
The lower part 4 has a large diameter lower part 14a and a lower large diameter part 14b.

An annular first core 301 and a second core 302 made of a soft magnetic material are fitted in the small diameter portion 14a in series in the axial direction with a predetermined gap 303 therebetween. At the upper end of the first core 301 and the lower end of the second core 302,
A flange 301a and a flange 302a are respectively formed, the first core 301 is inserted into the core mounting hole 14 from above, and the second core 302 is inserted into the core mounting hole 14 from below, and the flange 301a and the flange 302a are fitted to the edge of the core mounting hole 14. The first core 301 and the second core 302 are positioned by contact with each other, and the gap 303 is maintained at a predetermined distance.

Further, a cylindrical upper cap 305 is provided above the first core 301, and is fixed to the upper surface of the upper head 11 by passing a bolt 304 through a flange portion 305a formed at the lower end thereof. At this time, the lower end of the upper cap 305 including the flange portion 305a abuts on the peripheral edge of the upper surface of the first core 301, and by holding this, the first core 301 is fixed to the upper head 11.

On the other hand, an annular lower cap 307 is provided below the second core 302, and a bolt 30
7 penetrates and is fixed to the downward step surface of the step portion of the small diameter portion 14a and the large diameter portion 14b. At this time, the lower cap 307 abuts on the lower peripheral edge of the first core 302 and holds the lower core 307 so that the first core 301 can move the upper head 11.
Fixed to

A first electromagnetic coil 308 is mounted in a groove formed on the surface of the first core 301 on the side of the gap 303, and the same is provided on the surface of the second core 302 on the side of the gap 303. , A second electromagnetic coil 309 is mounted thereon, and the first electromagnetic coil 308 and the second electromagnetic coil 30
9 are arranged facing each other.

An annular armature 311 made of a soft magnetic material is arranged in the middle of the gap 303. The upper end of the armature 311 extends vertically from the center of the armature 311 to the inside of the upper cap 305 through the center of the first core 301, and the lower end of the upper core 305 of the second core 302. A columnar armature shaft 310 is provided to pass through the center and into the large-diameter portion 14b below the armature shaft 310. The armature shaft 310 is held so as to be able to advance and retreat in the axial direction.

A disc-shaped upper retainer 312 is joined to the base end of the armature shaft 310 extending into the upper cap 305, and an adjust bolt 313 is screwed into an upper opening of the upper cap 305. An upper spring 314 is interposed between the upper retainer 312 and the adjustment bolt 313. A spring seat 315 having an outer diameter substantially equal to the inner diameter of the upper cap 305 is interposed on the contact surface between the adjust bolt 313 and the upper spring 314.

On the other hand, the tip of the armature shaft 310 extending into the large diameter portion 12b is connected to the valve shaft 2 of the intake valve 28.
8b is in contact with the base end 28d. This base end 28d
A disc-shaped lower retainer 28c is joined to an outer periphery of the lower head 10, and a lower spring 316 is interposed between the lower surface of the lower retainer 28c and the upper surface of the lower head 10.

In the intake-side electromagnetic drive mechanism 30 configured as described above, when no exciting current is applied to the first electromagnetic coil 308 and the second electromagnetic coil 309, the armature shaft 310 is moved downward by the upper spring 314. (Ie, the direction in which the intake valve 28 is opened) and the upward force of the intake valve 28 by the lower spring 316 (ie, the direction in which the intake valve 28 is closed) act, and as a result, The state where the armature shaft 310 and the intake valve 28 are in contact with each other and elastically supported at a predetermined position, that is, a so-called neutral state is maintained.

The biasing force of the upper spring 314 and the lower spring 316 is set so that the neutral position of the armature 311 coincides with the intermediate position between the first core 301 and the second core 302 in the gap 303. You. When the neutral position of the armature 311 is deviated from the above-described intermediate position due to an initial tolerance or a secular change of the components, the neutral position of the armature 311 can be adjusted by the adjusting bolt 313 so as to match the above-described intermediate position. .

Further, the axial lengths of the armature shaft 310 and the valve shaft 28b are different from those of the armature 31.
When 1 is located at an intermediate position of the gap 303, the valve body 28a is set to an intermediate position between the fully open side displacement end and the fully closed side displacement end (hereinafter, referred to as a middle open position).

In the intake side electromagnetic drive mechanism 30 described above, when an exciting current is applied to the first electromagnetic coil 308, the first
Core 301, first electromagnetic coil 308, and armature 31
1, an electromagnetic force is generated in a direction to displace the armature 311 toward the first core 301, and when an exciting current is applied to the second electromagnetic coil 309, the second core 302 and the second electromagnetic An electromagnetic force is generated between the coil 309 and the armature 311 in a direction for displacing the armature 311 toward the second core 302.

Therefore, in the intake side electromagnetic drive mechanism 30,
The excitation current is alternately applied to the first electromagnetic coil 308 and the second electromagnetic coil 309, so that the armature 3
11, the valve body 28a is driven to open and close. At this time, the opening and closing timing of the intake valve 28 can be controlled by changing the excitation current application timing and the magnitude of the excitation current to the first electromagnetic coil 308 and the second electromagnetic coil 309.

Hereinafter, the fuel injection control at the time of starting according to the present embodiment will be described. After the ignition switch is turned on, an exciting current is applied to one of the first electromagnetic coil and the second electromagnetic coil for each electromagnetically driven valve,
As described above, in the armature in the neutral state, the electromagnetic force heading in both the valve opening direction and the valve closing direction acts alternately with a period equal to its natural vibration period, and the vibration amplitude of the armature increases to the fully closed position. Reach In this way, the intake and exhaust valves 28 and 29 are kept in the fully closed state during the initial startup during the cranking.

The crank position sensor 51 is provided to detect the rotation of the crankshaft 23,
The output signal is sent to the ECU 20. When the internal combustion engine is started, the crankshaft 23 is rotated by the rotation of the starter motor 55 to start cranking. At this time, the top dead center is detected within 360 ° CA based on the output signal of the crank position sensor 51.

The timing rotor 51a is provided with 34 teeth obtained by cutting two teeth out of 36 teeth at intervals of 10 °, and detects that the piston of the first cylinder 21a is at the top dead center. However, by providing the missing teeth also at the position where the piston of the second cylinder 21b is at the top dead center, the time for cylinder determination can be further reduced. That is, as shown in FIG. 5, the second cylinder is shifted 180 ° from the first notch 53 lacking two teeth for discriminating the first cylinder 21 a and the third cylinder 21 c on the periphery of the timing rotor 51 a. A second cutout portion 54 having one or three teeth missing is provided for discriminating the 21b and the fourth cylinder 21d.
As a result, cylinder discrimination is possible within a maximum of 180 ° CA.

FIG. 6 is a time chart showing a piston position and an ignition sequence for each cylinder when the internal combustion engine is started in this embodiment. In FIG. 6, the crankshaft is rotated by 180 ° when the scale is advanced by one division in the horizontal axis direction, and the piston is displaced between the top dead center (TDC) and the bottom dead center (BDC). Each cylinder is shown in the vertical direction according to the ignition order.

As shown, when the ignition switch is turned on at time T ₀ , the intake / exhaust valve is displaced from the half-open position to the fully closed position by the initial drive, and the starter switch is turned on at time T _1. The starter motor starts and cranking starts. In this case, the intake and exhaust valves may be displaced to the fully closed position during cranking.

After cranking is started, cylinder discrimination is performed, and for example, as shown in FIG. 6, it is detected that the piston of the first cylinder 21a is at the top dead center. At this time, the second cylinder 2
The piston 1b will be at the bottom dead center. And the first
When it is determined that the cylinder 21a has the intake valve closed and starts from the exhaust stroke, the second cylinder 21b is in the compression stroke. In the second cylinder 21b, almost simultaneously with the injection of fuel from the fuel injection valve 32,
When the intake valve 28 is opened for a short period, the fuel flows into the second cylinder 21b at a high flow rate because the inside of the second cylinder 21b has a negative pressure.

At this time, the piston has already started to move up and has entered the compression stroke. However, even if the intake valve 28 is opened, it is not the timing at which the air flows backward. Subsequently, the second cylinder 21
When the piston b reaches the compression top dead center, the ignition plug 25 of the cylinder is ignited.

As described above, according to the present embodiment, it is possible to ignite within 180 ° CA from the cylinder discrimination,
After the cylinder discrimination, the internal combustion engine 1 starts to start in half the time of the related art.

On the other hand, in the first cylinder 21a, the intake valve 28 is opened for a short time immediately before the piston next reaches the bottom dead center. At this time, since the pressure in the cylinder is negative, the flow velocity of the inflow air can be increased. Fuel is injected from the fuel injection valve 32 immediately before the intake valve 28 opens, but atomization can be promoted by the high flow velocity. Thereafter, ignition is performed at the next compression top dead center.

Similarly, the intake valve 28 opens at the bottom dead center of the third cylinder 21c with fuel injection, and then the fourth cylinder 21c
d, following the second cylinder 21b, fuel is independently injected into each cylinder, and the intake valve 28 of each cylinder opens in synchronization with this injection. Thereafter, ignition is performed one after another at the compression top dead center for each cylinder, the continuous rotation of the crankshaft 23 is secured, and the internal combustion engine reaches a state where it can maintain its own rotation (complete explosion). After the complete explosion, the intake and exhaust valves operate at normal valve timing, and fuel injection is performed as usual.

In this embodiment, the CPU 401
After the cylinder discrimination, the fuel injection and the opening / closing operation of the intake valve are immediately executed to the cylinder at the bottom dead center so as to be synchronized, and the cylinder is ignited within 180 ° CA.

In the above operation, the optimal opening / closing control of the intake valve is such that the piston is located immediately before the bottom dead center and is opened for a short time when the negative pressure in the cylinder is large to secure the negative pressure and the flow rate. It is. Further, the fuel injection overlaps with the opening state of the intake valve 28 immediately before the intake valve 28 opens, so that the atomization of the fuel is improved as much as possible by the negative pressure and the flow velocity.

FIG. 7 shows such optimal valve opening / closing and fuel injection timing. However, in the cylinder in which the first ignition is performed, that is, in the second cylinder 21b, since the piston has reached the bottom dead center at the time of the cylinder discrimination, the opening of the intake valve 28 and the amount of fuel passage at the start of the compression stroke. Injections are performed almost simultaneously.

Next, a second embodiment of the present invention will be described with reference to FIG. Internal combustion engine 1 used in this control
Reference numeral 00 denotes a so-called direct injection type internal combustion engine. The injection port of the fuel injection valve 70 is exposed in the combustion chamber 71 as shown in FIG. The fuel injection valve 70 is, for example, an electromagnetic injection valve including a needle valve body. The discharge side of a high-pressure fuel pump 73 is connected to the fuel injection valve 70 via a high-pressure supply passage 72.

The fuel injection valve 70 allows the fuel supplied from the high-pressure fuel pump 73 to move from the combustion chamber 7 by moving the valve body away from the valve seat in response to a control signal sent from the ECU 80.
Inject into 1. The piston 7 is provided inside the cylinder 74.
The piston 75 is slidable vertically in the cylinder 74. An intake port 76 and an exhaust port 77 are formed in the cylinder head 83 for each cylinder, and these are open into the combustion chamber 71. The cylinder head 8
Electromagnetic drive valves 78 and 79 are incorporated in 3, and an intake valve 80 and an exhaust valve 81 are provided respectively. The combustion chamber 7
1, an ignition plug 82 is provided.

In such a direct injection type internal combustion engine 100,
Injection is possible during the compression stroke, and injection is performed without opening and closing the intake valve as in a port injection type internal combustion engine.

FIG. 10 is a time chart showing the position of the piston and the ignition sequence for each cylinder when the internal combustion engine 100 is started in the second embodiment. In FIG. 10, the crankshaft is moved 18 degrees in the horizontal axis direction.
The piston is rotated by 0 °, and the piston is displaced between the top dead center (TDC) and the bottom dead center (BDC). Each cylinder is shown along the vertical axis in accordance with the ignition order.

As shown, when the ignition switch is turned on at time T ₀ , the intake / exhaust valve is displaced from the half-open position to the fully closed position by the initial drive, and then the starter switch is turned on at time T _1. Then, the starter motor 84 starts.

After the cranking is started, the cylinder is determined, and the crank position sensor detects, for example, the first cylinder 74a to the fourth cylinder 74d shown in FIG.
When it is detected that the piston of the cylinder 74a is at the top dead center, the piston of the second cylinder 74b is at the bottom dead center. The first cylinder 74a has an intake valve closed,
When the start from the exhaust stroke is confirmed, the second cylinder 74b enters the compression stroke. In the second cylinder 74b, fuel is injected during the compression stroke. Subsequently, when the piston of the second cylinder 74b reaches the compression top dead center, the ignition plug 82 of the cylinder is ignited. This ignition is 180 ° C from the cylinder discrimination.
A, the internal combustion engine 1 starts very early.

On the other hand, in the first cylinder 74a, fuel is injected from the fuel injection valve 70 during the next compression stroke, and thereafter, ignition is performed at the next compression top dead center. Similarly, fuel is injected into the third cylinder 74c during the compression stroke, and then similarly to the fourth cylinder 74c.
d, following the second cylinder 74b, fuel is independently injected into each cylinder during the compression stroke. Thereafter, ignition is successively performed at the compression top dead center for each cylinder, and continuous rotation of the crankshaft is secured, and the internal combustion engine reaches a state where it can maintain rotation by itself (complete explosion).

After the above strokes have been completed and the ignition of each cylinder has completed one cycle and the start of the internal combustion engine has been ensured, the intake and exhaust valves are controlled to the normal opening and closing timing as shown in FIG. The timing of injection is also controlled according to a normal routine. Further, for several tens of seconds after the complete explosion, the fuel is increased by increasing the amount of fuel after starting.

In the internal combustion engine of this embodiment, if the cylinder whose piston is at the top dead center is determined without discriminating the front and back of the cylinder by employing the electromagnetically driven valve, it is determined that the cylinder is at the compression top dead center. Since the valve operation can be started, the time for cylinder discrimination can be shortened. Further, after fuel is injected into the cylinder at the bottom dead center when the top dead center is detected, ignition can be performed within 180 ° CA from the cylinder discrimination.

[0078]

As described above, according to the present invention, the internal combustion engine can be started early while suppressing the emission of HC.

[Brief description of the drawings]

FIG. 1 is an overall side view showing a schematic configuration of an internal combustion engine of the present invention.

FIG. 2 is an overall plan view showing a schematic configuration of an internal combustion engine of the present invention.

FIG. 3 is a sectional view showing a structure of an electromagnetically driven valve of the internal combustion engine of the present invention.

FIG. 4 is a block diagram showing an internal configuration of an ECU.

FIG. 5 is a perspective view showing a timing rotor of the crank position sensor.

FIG. 6 is a time chart showing a piston position and an ignition sequence for each cylinder when the internal combustion engine is started.

FIG. 7 is a diagram showing a fuel injection timing and an intake valve opening / closing timing.

FIG. 8 is a schematic view showing a direct injection type internal combustion engine.

FIG. 9 is a conceptual diagram showing a cylinder arrangement of a direct injection type internal combustion engine.

FIG. 10 is a time chart showing a position of a piston and an ignition sequence for each cylinder at the time of starting of a direct injection type internal combustion engine. 1, 100: Internal combustion engine 20, 85: ECU 21a-21d, 74a-74d: Cylinder 22, 75: Piston 23: Crank shaft 25, 82: Spark plug 26, 76 ... intake ports 27, 77 ... exhaust ports 28, 80 ... intake valves 29, 81 ... exhaust valves 30, 78 ... intake side electromagnetically driven valves 31, 79 ... exhaust side electromagnetically driven Valves 32, 70: Fuel injection valve 51: Crank position sensor 51a: Timing rotor

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Claims (2)

[Claims] The present invention is characterized in that after detecting the piston position of each cylinder at the time of starting the internal combustion engine, the piston injects fuel to a bottom dead center and an arbitrary cylinder in a compression stroke from the bottom dead center at the time of this detection. An internal combustion engine having an electromagnetically driven valve. 2. The intake valve of any cylinder in which the fuel is supplied from an injector installed in an intake pipe outside the cylinder, the piston position is in a compression stroke from the bottom dead center and the bottom dead center, and fuel is injected. 2. An internal combustion engine having the electromagnetically driven valve according to claim 1, further comprising means for opening the valve with fuel injection.