JPH09177572A - Output controller of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reverse flowing of fuel so as to secure the supply of the necessary amount of fuel by providing a valve closing time control means for properly delaying the valve opening time of an air intake valve based on an output requested to an internal combustion engine and directing fuel injection away from the air intake valve. SOLUTION: In an internal combustion engine using a mirror cycle, the closing time of two air intake valves 18a and 18b is changed by a phase changing device 30. That is, the closing time of one air intake valve 18b is controlled so as to control an engine output. This valve closing time is advanced when a requested output is larger and delayed when the requested output is smaller. In this internal combustion engine, the injection port 16 of an injector is bent in its middle part by the attaching of an adapter 16d, atomized fuel is guided to an exhaust valve or an exhaust port in the left side with respect to the axis of the injector and directed to a side opposite the air intake valves 18a and 18 in the right side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output control device for an internal combustion engine to which a so-called Miller cycle is applied.

[0002]

2. Description of the Related Art Generally, in a gasoline engine, a mixture ratio of intake air (intake air) and fuel (air-fuel ratio; A / F) is limited to a narrow range, and particularly in an engine equipped with a three-way catalyst, the air-fuel ratio is Regardless of the operating condition, it is always controlled near a constant theoretical air-fuel ratio (A / F ≈ 14.7).

The amount of fuel supplied to the engine is
Since it depends on the required output to the engine at that time, it is necessary to reduce the amount of intake air when reducing the output (reducing the fuel flow rate). For this reason,
A throttle valve is provided in the intake passage, and the intake air amount is adjusted by throttling the passage with this throttle valve.

However, throttling of the passage at the time of partial load is inevitably an increase in intake resistance, and this throttling loss (pumping loss) is the largest factor that hinders the improvement of fuel efficiency of a gasoline engine.

On the other hand, there is known an output control method which applies a so-called Miller cycle, which is a combustion cycle in which the expansion stroke is longer than the compression stroke. According to this, output control by a throttle valve is not required. The pumping loss at the time of partial load can be reduced and the fuel consumption can be improved.

[0006] As a proposal regarding this, Japanese Patent Laid-Open No. 5430/1993
There is one disclosed in Japanese Patent Publication No. JP-A-2003-242, which controls the closing timing of the intake valve by using a phase changing device that changes the rotational phase of the camshaft. In this case, the intake valve is closed (so-called late closing) in the middle of the compression stroke (piston rising stroke), and the output decreases as the valve closing timing is delayed.

[0007]

By the way, in a normal engine, fuel injection is performed in an intake manifold to suck a mixture into a cylinder. However, in such an engine, the above-described output control device is provided. The combination causes the following problems.

That is, the injected fuel adheres to the inner wall of the intake manifold and the intake port, and when the intake air flows into the cylinder, it evaporates into a mixture, or flows through the inner wall and flows into the cylinder as it is. To do However, when performing output control by controlling the closing timing of the intake valve, the air-fuel mixture is pushed back from the inside of the cylinder due to the rise of the piston and flows back, so that back-flow also occurs in the air-fuel mixture in the intake manifold, etc. When the valve closing timing is suddenly changed, it may be difficult to supply the necessary fuel, and misfire may occur.

On the other hand, a direct injection type spark ignition engine is known which directly injects fuel into a cylinder to generate a rich air-fuel mixture around a spark plug and promotes exhaust gas cleaning and fuel efficiency improvement by stratified combustion. There is. According to this, the air-fuel ratio can be set high as a whole, stable combustion can be obtained even with an extremely lean mixture, and fuel consumption can be improved.

Therefore, if this is combined with the above-mentioned output control device, a dramatic improvement in fuel consumption can be expected.

However, even in this case, it is necessary to devise a method for preventing the fuel injected into the cylinder from flowing backward.

[0012]

SUMMARY OF THE INVENTION The present invention is a valve closing timing control means for appropriately delaying the valve closing timing of a fuel injection valve for directly injecting fuel into a cylinder and an intake valve based on a required output to an internal combustion engine. And a directing means for directing the fuel injected from the fuel injection valve toward the separation side with respect to the intake valve.

In this structure, since the directing means directs the fuel injected from the fuel injection valve toward the side away from the intake valve, the fuel spray can be kept away from the backflowing intake air. This makes it possible to prevent the reverse flow of fuel and reliably supply the required amount of fuel.

[0014]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a vertical sectional front view of an engine (internal combustion engine) to which an output control device according to the present invention is applied, and FIG. 2 is a side view showing a cylinder head alone. FIG. 1 shows A in FIG.
It corresponds to a section taken along line A, in which parts other than the cylinder head are also shown. FIG. 3 is a sectional view taken along line BB of FIG. Here, the engine employs a direct injection spark ignition engine configuration.

As shown in FIGS. 2 and 3, inside the cylinder head 1, two intake ports 2 are formed in parallel on one side of the cylinder head 1. Similarly, two exhaust ports 3 (only one of which is shown in FIG. 3) are formed in parallel on the opposite side portion. The intake port 2 and the exhaust port 3 are opened and closed by moving up and down an intake valve 18 and an exhaust valve 19 (shown by phantom lines) which are inserted and guided by the valve guide 4. Inside the cylinder head 1, above the valve guide 4, a valve spring and a cam shaft (indicated by reference numerals 22 and 23 in FIG. 1) are provided.
A storage chamber 5 for storing, etc. is defined. Here, the camshafts 22 and 23 are provided one on each of the intake side and the exhaust side, and have a four-valve DOHC configuration in which two pairs of intake valves 18 and two exhaust valves 19 are directly moved. A shaft receiving portion 7 for rotatably supporting the cam shafts 22 and 23 is formed at the upper end of the cylinder head 1.

The intake port 2 and the exhaust port 3, and the intake valve 18 and the exhaust valve 19 are inclined at a predetermined angle with respect to the center C of the cylinder and are substantially symmetrically inclined. An intake inlet portion of the intake port 2 is defined by an intake pipe portion 8 integrally formed with the cylinder head 1. Intake pipe section 8
Is projected outward from the intake side surface 1a of the cylinder head 1, and its inlet end is a flange 9 for connecting an intake manifold (not shown). The intake pipe portion 8 has a cross section of approximately 8 which is long in the front-rear direction (left-right direction in FIG. 2) so as to partition the two intake ports 2 having a circular cross-section.
The plug attachment surface portion 10 is formed at the root portion of the lower side of the inlet side surface portion 1a. Inside the cylinder head 1, a cooling water passage 11 for circulating cooling water is also formed.

As shown in FIG. 1, a cylinder 12 is mounted below the cylinder head 1.
A piston 13 is slidably housed therein. In the cylinder 12, a water jacket 14 that communicates with the cooling water passage 11 of the cylinder head 1 is formed.

The cylinder head 1 is provided with an injector accommodating hole 15 along a cylinder center C which coincides with the center of the piston 13. And this injector housing hole 1
The injector 16 (fuel injection valve) is accommodated in the valve 5, and the injector 16 is erected at the position of the cylinder center C and along the same. Then, the injector 16 comes to be surrounded by the intake port 2 and the exhaust port 3.

The injector accommodating hole 15 has a screw hole 15a at its lower end, and the injector 1 is inserted into the screw hole 15a.
The screw part 16b of 6 is screwed and attached. A communication hole 15b whose lower end opens toward the combustion chamber 17 is continuously provided below the screw hole 15a. Communication hole 15
b is composed of a fitting portion 15c having a constant diameter for fitting the injection opening portion 16c of the injector 16 and an injection opening portion 15d formed below the fitting portion 15c.

In particular, as shown in FIG.
The injection port 16a of No. 6 is bent in the middle by mounting the adapter 16d, and guides the fuel spray F to the exhaust valve 19 and the exhaust port 3 side on the left side in the figure with respect to the axis of the injector 16 and the right side in the figure. The intake valve 18 and the intake port 2 are directed to the opposite side (to the separating side). In response to this, the injection port portion 15d is also opened obliquely along the direction of the fuel spray F. That is, the cross section of the injection port portion 15d is formed in a long hole shape whose upper end has a circular shape with the same diameter as that of the fitting portion 15c, but which gradually becomes longer toward the exhaust valve 19 side as it goes downward.

Thus, the injection port 16a and the injection port portion 15
Reference character d forms a directing means for directing the fuel injected from the injector 16 toward the side away from the intake valve 18.

Reference numerals 2a and 3a are center lines of the intake port 2 and the exhaust port 3, respectively.

In the plug mounting surface portion 10 of the cylinder head 1, a plug mounting hole 20 having an enlarged insertion opening is formed substantially in parallel with the intake port 2. And spark plug 21
Are attached by screwing, and the electrode portion 21a is attached to the combustion chamber 1
7 is projected. The head surface 13a of the piston 13 is provided with a relief portion 24 for avoiding interference with the electrode portion 21a and a valve recess 25 for avoiding interference with the exhaust valve 19. Reference numeral 27 is a supply pipe for supplying fuel from a fuel rail (not shown) to the injector 16.

Next, an output control device for controlling the output of the engine will be described.

The engine is shown schematically in FIG. The previous intake valve 18 is two intake valves 18a and 18b, and these are directly moved by a camshaft 22. The intake ports 2 and 2 are jointly connected to the intake manifold 28. The reciprocating motion of the piston 13 causes the crankshaft 29 to rotate.

Here, the two intake valves 18a and 18b are
Each of them operates independently of each other so that the closing timing of the intake valve as a whole can be changed. The phase changing device 30 substantially performs this change.

As shown in detail in FIG. 6, the phase changing device 30 is constructed in the same manner as in Japanese Patent Laid-Open No. 59-183010 and has a camshaft 22 having a double pipe structure. Camshaft 2
Reference numeral 2 includes a phase fixed cam shaft 22a and a phase variable cam shaft 22b.
b is a fixed cam 31a that pushes the intake valves 18a and 18b.
And a variable cam 31b integrally. The fixed cam shaft 22a is relatively rotatably fitted to the outside of the variable cam shaft 22b, and the relative rotation is allowed by an intermediate bearing 32 fixed to one of the two. A timing pulley 33 is attached to an end portion of the fixed cam shaft 22a, and the timing pulley 33 serves as the timing belt 3
4, the input from the crankshaft 29 is transmitted via the drive pulley 35. As a result, the phase-fixed cam shaft 22a is interlocked with the crankshaft 29 and the phase is fixed with respect to the crank angle.

On the other hand, the input transmitted to the fixed cam shaft 22a is transmitted to the variable cam shaft 22b with a phase difference by the phase changing mechanism 30a. That is, the diagonal cam boss 36 is fixed to the fixed cam shaft 22a with the timing pulley 33 interposed therebetween. The oblique groove 37 of the boss 36 is formed obliquely in the circumferential direction with respect to the axial direction of the camshaft 22.
On the other hand, the grooved boss 38 is also provided at one end of the variable camshaft 22b.
Is fixed, and the groove 39 of the boss 38 is formed along the axial direction. A movable piece 40 is slidably fitted in these grooves 37, 39, and the movable piece 40 is integrally fixed to a movable bracket 41. The movable bracket 41 has a bearing 42.
The control lever 43 is attached so as to be rotatable relative to the movable lever 40 by moving the control lever 43 in the axial direction. It will be displaced with respect to 22a.

In the figure, reference numeral 44 is a bearing that axially supports the fixed and variable cam shafts 22a and 22b, and 45 is a valve spring.

The control lever 43 is substantially operated by the electric actuator 46 shown in FIG. Sending a control signal to this actuator 46 is an electronic control unit (EC
U) 47. The ECU 47 also has an injector 16
Basic control such as fuel injection control and ignition timing control is executed. Further, an accelerator stroke sensor 50 provided on an accelerator pedal 49 is connected to the ECU 47. The accelerator stroke sensor 50 outputs an electric signal to the ECU 47 according to the depression amount of the accelerator pedal 49. Then, based on this signal, the ECU 47 determines the required output required by the driver for the engine.

In particular, in the above configuration, the phase changing device 30, the actuator 46, the ECU 47 and the accelerator stroke sensor 50 delay the valve closing timing of the intake valve 18b so that the required output to the internal combustion engine is smaller. It constitutes a timing control means.

Here, a method of controlling the engine output by this apparatus will be described.

As mentioned above, such an arrangement is of a late closing Miller cycle, ie variable camshaft 22b.
One intake valve 18b (hereinafter referred to as the variable intake valve 18b
b), the other intake valve is referred to as a fixed intake valve 18a) and the closing timing of the intake valve is controlled to control the engine output.

Specifically, it is as follows. FIG. 7 is a valve lift diagram of the intake valves 18a and 18b and the exhaust valve 19, and the horizontal axis indicates the piston position corresponding to the crank angle. As can be seen from this, the fixed intake valve 18a always opens and closes at a constant timing, while the variable intake valve 1
In 8b, only the opening / closing timing thereof is equal to or delayed from the opening / closing timing of the fixed intake valve 18a while maintaining the same profile and lift amount.

That is, when the depression amount of the accelerator pedal 49 is less than the maximum, the opening / closing timing of the variable intake valve 18b is delayed or retarded. Then, the variable intake valve 18b is closed in the middle of the compression stroke while the piston is rising, and the intake air is backflowed into the intake port 2 and the intake manifold 28 during the compression stroke before the closing of the piston.
Along with this, the fuel injection amount is also reduced and the engine output is reduced. More specifically, the accelerator pedal 4
EC depending on the amount of depression of 9
The U 47 operates the control lever 43 via the actuator 46, changes the phase of the variable cam shaft 22b, and controls the closing timing of the variable intake valve 18b.

If the driver depresses the accelerator pedal 49 to the maximum, the required output becomes maximum and the variable intake valve 18
The opening / closing timing of b is matched with that of the fixed intake valve 18a.

As described above, in this configuration, the valve closing timing is
The larger the required output is, the more the angle is advanced, and the smaller the required output is, the more the angle is retarded. As described above, intake throttle is not performed by the throttle valve, so throttling loss (pumping loss) does not occur and fuel consumption is improved.

According to the above construction, the combination of the direct injection type spark ignition engine and the Miller cycle type output control device is achieved. Then, if the closing timing of the variable intake valve 18b is delayed, the intake air (air) in the cylinder 12 or the combustion chamber 17 will flow back into the intake port 2 or the intake manifold 28. On the other hand, during this backflow period, the fuel is also injected by the injector 16, and as described above, the backflow of the intake air also causes the backflow of the fuel, which makes it difficult to supply the necessary fuel and causes a problem such as misfire. It may occur.

Therefore, in such a structure, the injection port 16a and the injection port portion 15d, which are the substantial fuel injection ports, are formed as described above, and the fuel spray F is directed toward the separation side of the intake valve 18 so that the backflow air is generated. The influence is eliminated, and all the fuel is left in the cylinder 12 for combustion. As a result, sufficient fuel can be supplied, and problems such as misfire can be effectively prevented. Also,
Since the injector 16 injects the fuel downward, the backflow of the fuel can be prevented by the momentum of the fuel.

On the other hand, the merit of in-cylinder direct injection is inherited as it is, and by combining with the Miller cycle type output control device, fuel efficiency can be dramatically improved. That is,
In the Miller cycle, the compression ratio is made smaller than the expansion ratio, or this causes a problem such as knocking because the compression ratio becomes high at the full load that does not delay closing, that is, at the maximum output. Therefore, generally, at a full load in which the fixed intake valve 18a and the variable intake valve 18b have the same opening / closing timing, it is necessary to delay the closing timing of the intake valve from the bottom dead center so as not to raise the compression ratio too much. However, by combining with in-cylinder injection, the mixture temperature at the beginning of compression can be lowered by the specific heat of the fuel, and the mixture distribution in the cylinder is layered so that knocking is difficult The injection method has the advantage that knocking can be avoided even if the compression ratio of the full load is increased.

Even if the fuel injection is performed after the variable intake valve 18b is closed, the backflow of the fuel can be prevented. However, this is too much time to finish the fuel injection before the ignition timing during the high rotation operation. too short. Therefore, the fuel injection must be performed during the piston ascending from the bottom dead center to the ignition timing (before the top dead center), and the configuration in this case is very advantageous.

FIG. 8 particularly shows the injection port 16a and the injection port portion 1
5d and the variable intake valve 18b are schematically shown in a plan view. In the above-mentioned configuration, the injection port 16a and the injection port portion 1 are provided.
The outlet of 5d faces the intermediate position between the exhaust valves 19 and 19, and the direction of the fuel spray F is the intermediate position between the exhaust valves 19 and 19. However, this pointing direction is
It is only necessary to set it on the separated side with respect to b, and to avoid the area near the variable intake valve 18b shown by hatching in the figure. Therefore, for example, the directions of the outlets of the injection port 16a and the injection port portion 15d and the direction of the fuel spray F May be set in the diametrically opposite direction of the variable intake valve 18b, as indicated by virtual lines 15e and F ₁ .

Further, as described above, the fuel injected from the injector 16 is not directed by the means for inclining it like the injection port 16a or directing it through the injection port portion 15d.
There is also a method of directly injecting by injecting the injector appropriately or directly attaching to the injection position. In this case, the mounting hole of the injector directly forms the directing means for directing the fuel.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various embodiments are possible. This device can also be combined with a lean burn engine that performs lean combustion.

[0046]

The present invention exhibits the following excellent effects.

(1) The influence of the backflow of the intake air is eliminated, and the backflow of the fuel is surely prevented, so that problems such as misfire can be prevented.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of an engine to which an output control device according to the present invention is applied.

FIG. 2 is a side view showing a cylinder head alone.

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is an enlarged sectional view of a main part of FIG.

FIG. 5 is a configuration diagram of an output control device according to the present invention.

FIG. 6 is a vertical sectional view showing details of a phase changing device.

FIG. 7 is a valve lift diagram of an intake valve and an exhaust valve.

FIG. 8 is a schematic plan view showing a positional relationship between an injection port portion and a variable intake valve.

[Explanation of symbols]

 12 cylinder 15d injection port (directing means) 16 injector (fuel injection valve) 18b variable intake valve (intake valve) 30 phase change device (valve closing timing control means) 46 actuator (valve closing timing control means) 47 ECU (closing valve) Timing control means) 50 Accelerator stroke sensor (valve closing timing control means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02D 41/04 320 F02D 41/04 320

Claims (1)

[Claims] 1. A fuel injection valve for directly injecting fuel into a cylinder, a valve closing timing control means for appropriately delaying a closing timing of an intake valve based on a required output to an internal combustion engine, and an injection from the fuel injection valve. An output control device for an internal combustion engine, comprising: a directing means for directing the fuel to be injected to a side away from the intake valve.