JP2003074402A - Cylinder injection type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a cylinder injection type internal combustion engine excellent in fuel consumption performance and exhaust gas performance. SOLUTION: In this cylindrical injection type internal combustion engine, a cam phase variable device 43 to variably change not only the cam phase of an intake air side cam shaft 41 but also the closing time of an intake valve 31 is provided, a required quantity of intake air is obtained by exhausting a part of air sucked into a combustion chamber 4 until the intake valve is closed by setting the closing time of the intake valve at a proper time in a compressing process, and on the other hand, a required quantity of fuel is supplied into the combustion chamber from a fuel injection valve 51. Improvement in fuel consumption due to reduction of a pumping loss is thereby contrived by making it possible to adjust the output of the engine with a throttle fully opened, and exhaust gas is cleaned by a ternary catalyst 24 inexpensive and excellent in cleaning efficiency by setting the air-fuel ratio of the exhaust gas at a value close to a theoretical air-fuel ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder injection internal combustion engine, and more particularly to a cylinder injection internal combustion engine excellent in fuel consumption performance and exhaust gas performance.

[0002]

2. Related Background Art An in-cylinder injection type internal combustion engine is equipped with a fuel injection valve that directly injects fuel into a combustion chamber, and by injecting fuel in a compression stroke in a predetermined engine operating range, While making the overall air-fuel ratio lean, a fuel-rich mixture layer is formed in the vicinity of the spark plug to perform so-called layered combustion to reduce fuel consumption. On the other hand, since there is a demand to purify harmful components in exhaust gas during such lean operation as well, in general, an exhaust gas purification apparatus for a cylinder injection internal combustion engine stores NOx in an oxygen excess atmosphere and reduces it. It is equipped with a catalyst that exerts a purifying action in an oxygen excess atmosphere, such as a NOx storage catalyst that releases and reduces NOx in the atmosphere.

In order to further improve the fuel consumption of the cylinder injection type internal combustion engine, it is conceivable to keep the throttle fully open during engine operation to reduce pump loss. However, a large amount of air is taken in when the throttle is fully open. Since the air-fuel ratio of the air-fuel mixture becomes extremely lean especially in the low load region, stable engine operation becomes difficult, and a catalyst that exerts an exhaust gas purification action in an oxygen excess atmosphere is indispensable.

[0004]

However, a catalyst such as a lean NOx storage catalyst is more expensive than a three-way catalyst, which is advantageous in purifying exhaust gas of a cylinder injection type internal combustion engine particularly during lean operation. It is an obstacle. An object of the present invention is to provide an in-cylinder injection type internal combustion engine excellent in fuel consumption performance and exhaust gas performance at low cost.

[0005]

According to a first aspect of the present invention, there is provided a direct injection type internal combustion engine in which a fuel is directly supplied into the combustion chamber, and a closing timing of an intake valve is changed to enter the combustion chamber. An intake valve closing timing changing device for variably adjusting the amount of air taken in. In the direct injection internal combustion engine of claim 1, since the intake valve closing timing changing device variably adjusts the intake valve closing timing and thus the intake air amount to supply the required amount of air into the combustion chamber, the throttle valve is fully opened. The amount of intake air in the combustion chamber can be adjusted appropriately. For example, if the intake valve closing timing is changed so that the intake valve closes during the compression stroke, part of the air that was once drawn into the combustion chamber during the intake stroke burns during the compression stroke through the open intake valve. Since the intake valve is discharged from the room and then the intake valve is closed, an amount of intake air according to the intake valve closing timing is trapped in the combustion chamber. Also, by setting the intake valve closing timing so that the intake valve closes early in the middle of the intake stroke, a required amount of intake air can be confined in the combustion chamber. On the other hand, a required amount of fuel can be supplied from the fuel supply device into the combustion chamber. As described above, by appropriately adjusting the intake air amount and the fuel amount in the combustion chamber, the engine output can be adjusted while the air-fuel ratio of the air-fuel mixture in the combustion chamber is set to a value near the theoretical air-fuel ratio, for example. That is, even when the required engine output changes, pump loss and fuel consumption are reduced by engine operation with the throttle fully open, while the air-fuel ratio of the air-fuel mixture in the combustion chamber and thus the exhaust air-fuel ratio in the exhaust passage is changed to the theoretical air-fuel ratio. It can be a nearby value. Therefore, the engine operation can be stabilized, and the three-way catalyst can be used for exhaust gas purification. The three-way catalyst is cheaper than the lean NOx storage catalyst, and is excellent in durability and purification efficiency. Therefore, according to the present invention, an in-cylinder injection type internal combustion engine excellent in fuel consumption performance and exhaust gas performance is provided at low cost. Further, since the fuel can be supplied into the combustion chamber after the intake valve is closed, the air-fuel mixture does not return from the combustion chamber to the intake passage, and the air-fuel ratio of the air-fuel mixture in the combustion chamber in the next cycle is not affected. The air-fuel ratio of the mixture becomes appropriate.

A cylinder injection type internal combustion engine according to claim 2 is
At engine start-up and engine operating range other than high load range,
It is characterized in that the fuel is supplied from the fuel supply device into the combustion chamber in the compression stroke. In the in-cylinder injection type internal combustion engine of claim 2, fuel injection is performed during the compression stroke at the time of engine startup and in operating regions other than the high load region. In this case, the intake valve is closed when a required amount of air is sucked into the combustion chamber, and then the fuel is supplied into the combustion chamber, whereby the air-fuel ratio of the air-fuel mixture in the combustion chamber can be set to an appropriate value. On the other hand, when the engine is started or in a high load region, for example, during the intake stroke, fuel is supplied to sufficiently vaporize the fuel in the combustion chamber for good combustion, or to increase the charging efficiency by fuel cooling to improve the output. be able to.

The cylinder injection type internal combustion engine according to claim 3 is
A cylinder deactivation device for deactivating at least one specific cylinder is provided. In the in-cylinder injection type internal combustion engine of the third aspect, the cylinder deactivation device stops the engine operation for one or more specific cylinders, for example, in a low load range. This cylinder rest device
For example, the fuel supply to a specific cylinder may be stopped,
It is also possible to stop the intake valve or the exhaust valve. As the engine load, that is, the required engine output, decreases, it is necessary to reduce the intake air amount and the fuel supply amount, but in order to reduce the intake air amount, when closing the intake valve in the compression stroke, the intake valve closing timing Must be retarded,
Further, when closing the intake valve in the intake stroke, the intake valve closing timing must be advanced. In other words, in order to control the engine output over a wide range, the changeable range of the intake valve closing timing must be widened, and the fuel supplyable period becomes short.

In this respect, in the internal combustion engine according to the third aspect of the present invention, by making one or more specific cylinders in the cylinder deactivated state in the low load range, the intake air amount and the fuel supply amount to the cylinders in the non-deactivated cylinder state are reduced. Since it can be increased by that amount, the changeable range of the intake valve closing timing can be narrowed by that amount, and the fuel supplyable period can be lengthened, contributing to stabilization of engine operation.

A cylinder injection type internal combustion engine according to claim 4 is
A first exhaust passage communicating with a first cylinder group including at least one cylinder, and a second exhaust passage including another at least one cylinder
A second exhaust passage communicating with the cylinder group and blocked from the first exhaust passage; and a first catalyst arranged in the middle of the first exhaust passage,
A second catalyst disposed in the middle of the second exhaust passage, and the cylinder deactivation device selects either the first cylinder group or the second cylinder group as the specific cylinder to bring the cylinder into a deactivated state. Is characterized by.

According to another aspect of the cylinder injection internal combustion engine of the present invention, when one of the first and second cylinder groups is deactivated, air is transferred from the cylinder group in the deactivated state to one of the first and second exhaust passages. Are discharged, and the catalyst arranged in the exhaust passage is arranged in the oxidizing atmosphere. If this catalyst does not exert a purifying action in an oxidizing atmosphere, the air in one of the exhaust passages will be exhausted to the outside as it is, but there is no problem because the air does not contain any toxic components. The harmful components in the exhaust gas discharged from the cylinder group in the other side to the other exhaust passage are purified by the catalyst provided in the exhaust passage. Then, although the catalyst used for exhaust gas purification deteriorates, the degree of deterioration of both catalysts can be reduced by switching the cylinder deactivation target between the first cylinder group and the second cylinder group, for example, every certain engine operating period. They can be made equivalent, and the purification performance of both catalysts can be effectively used.

A cylinder injection internal combustion engine according to a fifth aspect is
It is characterized by including a three-way catalyst disposed in the middle of the exhaust passage. In the cylinder injection internal combustion engine of claim 5, the exhaust gas is purified by the inexpensive three-way catalyst excellent in durability and purification efficiency, and the exhaust gas performance of the cylinder injection internal combustion engine can be improved at low cost. From this point of view, it is preferable that the first and second catalysts of claim 4 are three-way catalysts.

A cylinder injection internal combustion engine according to a sixth aspect is
One or more of the intake valve closing timing, the cylinder deactivation period, and the air-fuel mixture ratio in the combustion chamber are controlled according to the required engine output. In the cylinder injection type internal combustion engine of claim 6,
One or more of the fuel supply device, the intake valve closing timing changing device, and the cylinder deactivation device are controlled according to the required engine output, so that one of the intake valve closing timing, the cylinder deactivation period, and the mixture air-fuel ratio. The above is controlled according to the required engine output, and the engine output commensurate with the required engine output is generated.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, referring to FIG. 1 and FIG.
A cylinder injection internal combustion engine according to a first embodiment of the present invention will be described. The internal combustion engine of the present embodiment is, for example, an in-cylinder injection gasoline engine for a vehicle, includes a cylinder head 1 as shown in FIG. 1, and a combustion chamber 4 of each cylinder by a cylinder head 1, a cylinder 2 inner surface, and a piston 3. The cylinder head 1 is formed with an intake port 11 and an exhaust port 21 of each cylinder. The intake port 11 is connected to an intake pipe 15 via an intake manifold 12, a surge tank 13, and a throttle body 14, elements 11 to 15 constitute an intake passage, and the throttle body 14 has an electronically controlled slot valve 14a. Is built in. A bypass intake passage 16 is provided in the intake passage to bypass the throttle body 14, and a bypass intake valve 16a for adjusting the amount of air supplied through the bypass intake passage 16 is provided in the middle of the bypass intake passage 16. Also, the exhaust port 21
Is connected to an exhaust pipe 23 via an exhaust manifold 22, and a three-way catalyst 24 as an exhaust purification device is arranged in the middle of the exhaust pipe 23.

An intake valve 31 and an exhaust valve 32 are arranged at the openings of the intake port 11 and the exhaust port 21 on the side of the combustion chamber 4, and the upper ends of the stems of the intake valve 31 and the exhaust valve 32 are the intake side and exhaust side camshafts. 41 and 42 are in contact with the cam surfaces of the intake cam and the exhaust cam, respectively, and the intake valve 3 is rotated as the cam shafts 41 and 42 rotate.
1 and the exhaust valve 32 are adapted to open and close.

The engine is also equipped with an intake valve closing timing changing device, such as a hydraulic cam phase changing device 43, for variably adjusting or changing the closing timing of the intake valve 31.
Although not shown, the cam phase varying device 43 is, for example, a vane housing that is integrally rotatable with a cam sprocket drivingly connected to a crankshaft of an engine, and a vane housing that is integrally rotatable with an intake side camshaft. A vane rotor having a vane housed therein,
By supplying and discharging pressure oil to and from the oil chamber formed between the vane and the vane housing, the intake side camshaft 4
The cam phase of 1 and the opening / closing timing of the intake valve 31 are variable.

Further, the cylinder head 1 is provided with a fuel injection valve 51 capable of directly injecting fuel into the combustion chamber 4 as a fuel supply device, and an ignition plug 52 for igniting the air-fuel mixture in the combustion chamber. Is installed. As shown in FIG. 2, the exhaust manifold 22 is composed of first to fourth exhaust manifolds 22a to 22d that are respectively communicable with the combustion chambers 4 of the first to fourth cylinders of the engine. , 22d communicate with the first exhaust pipe 23a of the exhaust pipe 23, while the second and third exhaust manifolds 22b, 22c communicate with the second exhaust pipe 23b. Then, the first and second three-way catalysts 24a and 24b are arranged in the middle of the first and second exhaust pipes 23a and 23b, respectively. The first exhaust pipe 23a and the second exhaust pipe 23b are shielded from each other by a shield member 23c extending therebetween, and the shield member 23c shields the first and second three-way catalysts 24a and 24b from each other.

Reference numeral 5 indicates an engine control unit (hereinafter referred to as an ECU) for driving and controlling each part of the engine, and an input side thereof is, for example, an intake pressure sensor for detecting an intake passage internal pressure, an engine speed sensor, or the like. Various sensors (not shown) are connected. The ECU 5 controls the valve opening time (fuel supply amount) and opening timing of the fuel injection valve 51, the ignition timing of the ignition plug 52, the cam phase varying device according to the engine operating state and the vehicle operating state determined based on the outputs of various sensors. The hydraulic pressure supply to 51, the valve opening degree of the throttle valve 14a, the valve opening degree of the bypass intake valve 16a, etc. are controlled.

The control of the throttle opening, intake valve closing timing and fuel injection by the ECU 5 will be described below with reference to FIG. For example, when the ignition switch is turned on, the ECU 5 periodically executes the control routine shown in FIG. In each execution cycle of the control routine of FIG.
The CU 5 reads, for example, the output of the pressure sensor and outputs the output value and a determination reference value for determination at the time of starting (for example, -100 mmH).
By comparing with g), it is determined whether or not the engine is starting (step S1). It is possible to determine whether or not the engine is starting based on the estimated value of the intake pipe internal pressure calculated from the throttle opening.

When it is determined that the pressure sensor output is less than the determination reference value and the engine is being started, the throttle valve 1
4a is fully closed (step S2), and then the closing timing of the intake valve 31 of each cylinder is set (step S3).
Setting of the intake valve closing timing in each load region will be described in detail later with reference to FIG. 4, but the intake valve closing timing at the time of engine start is set to an appropriate timing from the first half to the middle half of the compression stroke. Then, an electromagnetic directional control valve (not shown) relating to the supply and discharge of the pressure oil to and from the cam phase varying device 43 is controlled so that the intake valve 31 is closed at this set timing. In the next step S4,
Under the control of the ECU 5, the fuel injection valve 51 is opened during the intake stroke.

If the determination result in step S1 is negative, for example, the output value of the intake pipe pressure sensor is compared with the determination reference value for determining the extremely low load region to determine whether it is in the extremely low load region. If it is in the extremely low load range, the throttle valve opening is set according to, for example, the accelerator opening (step S12). Then, the fuel supply to the fuel injection valve 51 corresponding to the specific cylinder, for example, the first and fourth cylinders (first cylinder group) or the second and third cylinders (second cylinder group) is stopped (step S13), Then, the intake valve closing timing is set to an appropriate timing from the middle stage to the latter stage of the compression stroke (step S1).
4) The supply and discharge of pressure oil to the cam phase varying device 43 is controlled so that the intake valve 31 is closed at the set closing timing. Furthermore,
The fuel injection valve 51 corresponding to a cylinder other than the specific cylinder is driven (step S15). As described above, by stopping the fuel supply to the specific cylinders, the specific cylinders are in the cylinder deactivated state, while the cylinders other than the specific cylinders are in the cylinder deactivated state.

If the determination results in steps S1 and S11 are both negative, it is determined whether or not it is in the low load range as in the above case (step S21), and if it is in the low load range, the throttle is fully opened. Thus, the throttle valve 14a is driven (step S22), and then steps S23 to S25 corresponding to steps S13 to S15 are sequentially executed.

If the determination results in steps S1, S11 and S21 are all negative, it is determined whether the engine is operating in the medium load range (step S31). If the engine is in the medium load range, the throttle is fully opened. And (step S3
2) Next, the intake valve closing timing is set to an appropriate timing from the middle stage to the latter stage of the compression stroke (step S33), and the cam phase varying device 43 is driven so that the intake valve closes at the set timing.
Further, the compression stroke injection is performed by the fuel injection valve 51 (step S34).

If all the determination results in steps S1, S11, S21 and S31 are negative, it is determined that the engine is in the high load range and the throttle is fully opened (steps S41, S4).
2) Next, the intake valve closing timing is set to an appropriate timing from the first half to the middle stroke of the compression stroke to drive the cam phase varying device 43 (step S43), and the intake stroke injection is performed by the fuel injection valve 51 (step S44). ).

The setting of the intake valve closing timing in each engine operating range will be further described below with reference to FIG. As described above, the amount of intake air trapped in the combustion chamber 4 and used for combustion changes according to the intake valve closing timing. Therefore, it is necessary to set the intake valve closing timing commensurate with the intake air amount required to generate the required engine output, and the required engine output is calculated for setting the intake valve closing timing.

In the present embodiment, the required engine output (target value) is set based on one or more of the engine speed, accelerator opening, throttle opening, volumetric efficiency, net mean effective pressure, indicated mean effective pressure, and intake manifold internal pressure. Load) is calculated. For example, the volumetric efficiency is obtained based on the accelerator opening and the engine speed, and the indicated mean effective pressure corresponding to the filling efficiency obtained from the volumetric efficiency and the intake density is obtained as the target load (requested engine output). Further, the engine operating range is discriminated from the target load and the engine speed.

As described above, the ECU 5 determines the intake valve closing timing.
The intake valve closing timing is advanced as the load increases, as a result of which the intake valve closing timing is increased based on the required engine output (load) calculated by the above, thereby increasing the intake air amount. Further, in setting the intake valve closing timing, whether or not fuel is supplied to the specific cylinder is taken into consideration. That is, while fuel supply to a specific cylinder is stopped in an extremely low load range or a low load range, fuel is supplied to all cylinders in a medium load range or a high load range at the time of starting, so that the engine operating range is low load. When shifting from the region to the medium load region, the stop of fuel supply to the specific cylinder is released, and all the cylinders contribute to the generation of engine output. Therefore, it is necessary to reduce the intake air amount for each cylinder by the increase in the number of cylinders so that the engine output smoothly and continuously changes during the transition from the low load range to the medium load range. During the transition, the intake valve closing timing is discontinuously retarded.

As described above, by stopping the fuel supply to the specific cylinder in the low load range and releasing the fuel supply stop in the medium load range, the engine output can be widened even if the variable range of the intake valve closing timing is narrow. It becomes possible to change over. That is, if the fuel supply to the specific cylinder is not stopped in the low load range, it is necessary to advance the intake valve closing timing as the load increases in the low load range and the medium load range as a whole, in order to adjust the engine output. Fig. 4 shows the variable range of the intake valve closing timing of
It has to be expanded significantly compared to the ones.

Further, in the present embodiment, the intake air is adjusted so that the air-fuel ratio of the air-fuel mixture in the combustion chamber becomes the theoretical air-fuel ratio in any engine operating range, or at least in an extremely low load range, a low load range or a medium load. The valve closing timing (intake air amount) and the fuel injection amount are controlled. Since the air-fuel ratio of the air-fuel mixture becomes the stoichiometric air-fuel ratio in this way, the exhaust air-fuel ratio in the exhaust pipe 23 also takes a value near the stoichiometric air-fuel ratio, and the three-way catalyst 24 satisfactorily purifies harmful components in the exhaust gas. It will be possible.

When the fuel supply to a specific cylinder, for example, the first and fourth cylinders is stopped, air is discharged from the first and fourth cylinders, and the discharged air is the first and fourth exhaust manifolds 22a, 22d and It is released into the atmosphere through the first exhaust pipe 23a. At this time, since an oxidizing atmosphere is formed around the first three-way catalyst 24a,
Although the purifying action of the three-way catalyst 24a is not achieved, the exhaust air does not contain harmful components and thus does not cause a problem. On the other hand, the second exhaust pipe 23b from the second and third cylinders via the second and third exhaust manifolds 22b and 22c.
The exhaust gas discharged inside is purified by the second three-way catalyst 24b and then discharged into the atmosphere.

As described above, while the fuel supply to the specific cylinder is stopped, only the three-way catalyst corresponding to the non-specific cylinder is used for exhaust gas purification and deteriorates. By switching the specific target from the first and fourth cylinders to the second and third cylinders, the first and second three-way catalysts 24a,
The degree of deterioration of 24b should be the same. Hereinafter, a cylinder injection type internal combustion engine according to a second embodiment of the present invention will be described.

The internal combustion engine of this embodiment has substantially the same structure as that of the first embodiment, but the first embodiment selects fuel supply to a specific cylinder according to the required engine output (engine load). The intake valve closing timing (intake air amount) is continuously variably adjusted so that the mixture air-fuel ratio becomes the stoichiometric air-fuel ratio, whereas in the present embodiment, the intake valve closing timing is requested. In accordance with the engine output, the intake valve closing timing is gradually changed to, for example, three stages as shown in FIG. 5, and the air-fuel mixture mixture is made rich as the required engine output increases.

The intake valve closing timing control and the mixture air-fuel ratio control in this embodiment will be further described below. As shown in FIG. 5, the intake valve closing timing is set to the retard side when the engine is operating in the extremely low load range or the low load range, and is advanced discontinuously at the transition from the low load range to the medium load range. Furthermore, the angle is further advanced discontinuously when shifting from the medium load range to the high load range. For this reason, the intake air amount for each cylinder increases discontinuously when transitioning from the low load region to the medium load region, so that the air-fuel ratio of the air-fuel mixture changes discontinuously toward the lean direction during the transition. The fuel injection amount from the engine is reduced so that the engine output becomes substantially the same before and after the transition. On the other hand,
Except at the time of transition from the low load region to the medium load region, the air-fuel mixture mixture becomes richer as the engine load increases, thereby generating an engine output commensurate with the required engine output.

As described above, in this embodiment, since the intake valve closing timing and the air-fuel ratio of the air-fuel mixture are changed, the intake valve closing timing and the air-fuel mixture for generating the required engine output in the entire engine load range. It is possible to suppress the amount of change in the air-fuel ratio. When a three-way catalyst is used for exhaust gas purification, it is preferable to change the air-fuel ratio of the air-fuel mixture around the stoichiometric air-fuel ratio. Although the description of the embodiment is completed above, the present invention is not limited to the above-described first and second embodiments, and can be variously modified.

For example, in the embodiments, the case where the present invention is applied to a gasoline engine has been described, but the present invention can also be applied to a diesel engine. Although the intake valve is closed during the compression stroke in the embodiment, it may be closed earlier during the intake stroke. In this case, the intake valve closing timing is advanced as the required engine output increases.

Further, in the embodiment, the case where the intake valve closing timing changing device is constituted by the cam phase changing device has been described, but an electromagnetic intake valve whose opening / closing timing can be variably adjusted may be used. Further, in the embodiment, the cylinder deactivation device is configured by the ECU and the fuel injection valve to perform the cylinder deactivation by stopping the fuel supply to the specific cylinder. However, the rocker arm and the rocker shaft related to the intake valve of the specific cylinder are Conventionally known cylinder deactivation device capable of selectively releasing the coupling of hydraulic pressure and a spring mechanism (for example, the one described in JP-A-7-180575).
May be used to deactivate a specific cylinder.

In the embodiment, the exhaust purification device provided with only the three-way catalyst is used, but an exhaust purification device provided with a lean NOx catalyst or the like may be used instead of the three-way catalyst or together with the three-way catalyst. Further, in the embodiment, the throttle valve of the intake throttle valve type is provided in the middle of the intake passage, but the present invention can be applied to an internal combustion engine that does not include this kind of throttle valve. The non-throttle type engine is suitable when the engine is not operated in an extremely low load range.

Besides, the present invention can be variously modified within the concept of the invention.

[0038]

The cylinder injection type internal combustion engine according to the first aspect of the present invention is a fuel supply device capable of directly supplying fuel into the combustion chamber, and air sucked into the combustion chamber by changing the closing timing of the intake valve. Since it is equipped with an intake valve closing timing changing device that variably adjusts the amount of intake air, the amount of intake air and the amount of fuel in the combustion chamber are adjusted as appropriate to reduce pump loss and fuel consumption due to engine operation with the throttle fully open. At the same time, the exhaust gas can be purified by a three-way catalyst that is inexpensive, and has excellent durability and purification efficiency, and therefore has excellent fuel efficiency and exhaust gas performance.

The in-cylinder injection type internal combustion engine according to claim 2 is
At engine start-up and engine operating range other than high load range,
Fuel is supplied from the fuel supply device to the combustion chamber in the compression stroke, so that the air-fuel ratio of the air-fuel mixture in the combustion chamber is optimized at engine startup and in operating regions other than the high load region to obtain good engine output performance and exhaust gas performance. In addition, the engine startability can be improved, and the required engine output can be obtained in the high load range.

The cylinder injection type internal combustion engine according to claim 3 is
Since the cylinder deactivation device for deactivating at least one specific cylinder is provided, the specific cylinder is deactivated as necessary to increase the intake air amount and the fuel supply amount to the non-deactivated cylinder, thereby increasing the intake valve closing timing. The change range of can be narrowed, and the period during which fuel can be supplied is lengthened to enable stable engine operation.

The cylinder injection internal combustion engine according to claim 4 is
A first exhaust passage communicating with the first cylinder group, a second exhaust passage communicating with the second cylinder group and blocked from the first exhaust passage,
Since the cylinder deactivation device is provided with the first and second catalysts arranged in the middle of the first and second exhaust passages and one of the cylinder groups is deactivated, the air from the deactivated cylinder group is exhausted. The exhaust gas from the non-deactivated cylinder group does not cause a problem because it is purified by the catalyst in the other exhaust passage. By switching between the second cylinder group and the second cylinder group, the degree of deterioration of both catalysts can be made equal, and the purification performance of both catalysts can be effectively used.

The cylinder injection type internal combustion engine according to claim 5 is
Since the three-way catalyst disposed in the middle of the exhaust passage is provided, the exhaust gas can be purified by the inexpensive three-way catalyst excellent in durability and purification efficiency. The in-cylinder injection internal combustion engine according to claim 6 controls at least one of the intake valve closing timing, the cylinder deactivation period, and the air-fuel mixture ratio in the combustion chamber according to the required engine output. It is possible to generate an engine output commensurate with the output.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a cylinder injection internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a partial schematic diagram showing in detail the exhaust system and the three-way catalyst shown in FIG.

FIG. 3 is a flowchart of a control routine executed by the ECU of FIG. 1 when controlling throttle opening, intake valve closing timing, and fuel injection.

4 is a diagram showing setting of intake valve closing timing according to engine load and stopping of fuel supply to a specific cylinder, which is performed in the control routine of FIG. 3;

FIG. 5 is a diagram showing setting of an intake valve closing timing and a mixture air-fuel ratio according to an engine load in a cylinder injection type internal combustion engine of a second embodiment of the present invention.

[Explanation of symbols]

4 Combustion chamber 5 Engine control unit (cylinder deactivation device) 14a Throttle valve 22, 22a, 22b, 22c, 22d Exhaust manifold 23, 23a, 23b Exhaust pipe 23d Shielding member 24, 24a, 24b Three-way catalyst 31 Intake valve 43 Cam phase Variable device (intake valve closing timing changing device) 51 Fuel injection valve (fuel supply device)

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) F01N 3/24 F01N 3/24 G R U 3/28 301 3/28 301B 301H F02D 13/02 F02D 13 / 02 D 13/06 13/06 C 17/02 17/02 M 41/02 330 41/02 330A 41/04 335 41/04 335C 41/06 335 41/06 335Z 43/00 301 43/00 301H 301J 301Z F-term (reference) 3G018 AA05 AA11 AB02 AB08 AB17 BA33 BA34 CA11 CA19 DA34 DA48 DA70 DA71 DA75 EA02 EA11 EA21 EA24 EA26 EA31 EA32 FA02 FA07 FA16 GA07 GA09 3G084 AA01 AA03 AA04 BA05 BA09 BA10 BA11 BA02 BA01 BA17 BA15 BA17 BA17 BA17 BA15 BA17 BA17 BA17 EB01 EB04 FA10 FA11 FA33 FA36 FA38 FA39 3G091 AA02 AA17 AA18 AA24 AA28 AB03 AB05 BA00 BA03 BA14 BA15 BA19 CB02 CB03 CB05 CB06 CB07 CB08 DA01 DA02 DA03 DA08 DB10 EA01 EA03 EA06 EA07 EA26 FA01 FA05 FA12 FA13 FA14 FB02 FB03 FB10 FB11 FB12 FC04 FC07 FC08 GA06 HA11 HB02 3G092 AA01 AA06 AA09 AA11 AB02 HA01 GA01 HA02 GA01 HA01 GA12 HA12 GA01 HA12 GA12 FA12 FA12 FA12 FA01 FA05 FA12 FA01 FA05 FA12 FA01 FA05 GA12 FA15 GA01 FA02 GA01 FA02 FA01 FA05 FA02 FA01 FA02 FA01 FA05 FA12 FA01 FA05 FA01 FA05 FA12 FA01 FA05 GA01 HA16 HA19 JA02 JA21 KA01 KA05 KA06 LB04 MA18 MA24 NE06 NE12 PA07Z PE01Z PF16Z

Claims (6)

[Claims] 1. An intake valve closing timing changing device that variably adjusts the amount of air taken into the combustion chamber by changing the closing timing of the intake valve; and fuel that can directly supply fuel to the combustion chamber and the intake air. A cylinder injection internal combustion engine, comprising: a fuel supply device that supplies fuel after a valve closing time. 2. The in-cylinder injection according to claim 1, wherein fuel is supplied from the fuel supply device into the combustion chamber during a compression stroke during engine startup and in an engine operating region other than a high load region. Type internal combustion engine. 3. The in-cylinder injection internal combustion engine according to claim 1, further comprising a cylinder deactivation device for deactivating at least one specific cylinder. 4. A first exhaust passage communicating with a first cylinder group consisting of at least one cylinder, and a first exhaust passage communicating with a second cylinder group consisting of another at least one cylinder, and isolated from the first exhaust passage. Two exhaust passages, a first catalyst arranged in the middle of the first exhaust passage, and a second catalyst arranged in the middle of the second exhaust passage, wherein the cylinder deactivation device includes the first cylinder group 4. The in-cylinder injection internal combustion engine according to claim 3, wherein any one of the second cylinder group is selected as the specific cylinder to bring the cylinder into a deactivated state. 5. The in-cylinder injection internal combustion engine according to claim 1, further comprising a three-way catalyst arranged in the exhaust passage. 6. The method according to claim 3, wherein at least one of an intake valve closing timing, a cylinder deactivation period, and a mixture air-fuel ratio in the combustion chamber is controlled according to a required engine output. Cylinder injection type internal combustion engine.