JP3087538B2 - Internal combustion engine - Google Patents

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.

[0002]

2. Description of the Related Art There is known an internal combustion engine having an in-cylinder injection fuel injection valve for injecting fuel into a cylinder and an intake port injection fuel injection valve for injecting fuel into an intake port. See JP-A-63-154816). In this internal combustion engine, fuel is injected into the cylinder from the in-cylinder fuel injection valve during low engine load operation, and the injected fuel is burned in the presence of a large amount of air.

[0003]

However, when the fuel injected into the cylinder from the in-cylinder fuel injection valve is made to burn in the presence of a large amount of air as in the above-mentioned internal combustion engine, the intake port injection The maximum combustion pressure in the cylinder is larger than in the case of injecting fuel from the fuel injection valve to fill the entire combustion chamber with the air-fuel mixture, and in this case, the combustion speed is also high, so the torque fluctuation in the engine cycle increases. I will be. However, when the torque fluctuation in the engine cycle increases, the vibration transmitted from the engine body to the vehicle increases, and there is a problem that the vibration is amplified by resonance during low-speed operation of the engine. Further, there is a problem that muffled sound is generated in the vehicle due to the vehicle vibration. Further, in a vehicle equipped with an automatic transmission capable of lock-up, when fuel is injected from the in-cylinder fuel injection valve when the vehicle is locked up, vibration transmitted to the vehicle body is further increased, and There is a problem that the noise generated in the inside is also increased.

[0004]

According to a first aspect of the present invention, there is provided a combustion chamber having a limited area within a combustion chamber.
Air-fuel mixture only at the same time, and this air-fuel mixture is
Stratified combustion, which ignites and burns, and fills the entire combustion chamber.
Homogeneous fuel that forms a mixture and burns the mixture
And combustion control means capable of switching and baked, in an internal combustion engine having a power transmission means capable of lockup, and to perform the homogeneous combustion in Rutoki has become b Kkuappu state. According to the second aspect of the present invention to solve the above-mentioned problem, the air-fuel mixture is only injected into a limited area in the combustion chamber.
The mixture is formed and ignited by the spark plug to burn
The stratified combustion and the mixture that fills the entire combustion chamber are formed.
Switch to homogeneous combustion that burns this mixture
In an internal combustion engine equipped with possible combustion control means and lockable power transmission means, homogeneous combustion should be performed.
When the vehicle speed is higher than the first set speed, the lock-up state is maintained, and when stratified combustion is to be performed , the vehicle speed is higher than the second set speed higher than the first set speed. Sometimes we try to keep it in lockup. According to a third aspect of the present invention, an air-fuel mixture is formed only in a limited area in a combustion chamber.
At the same time, this mixture is ignited by a spark plug and burned.
To form a mixture that fills the entire combustion chamber.
Switchable between homogeneous combustion that burns leverage mixture
An internal combustion engine equipped with a Do combustion control means, and the <br/> so performing homogeneous combustion when the car both speed is below the set predetermined rate.

[0005]

[Action] In the first invention, the lockup state is established.
Agencies cycles in the torque fluctuation is reduced to have Rutoki. 2
Th In the invention, it is maintained in b Kkuappu state when engine cycle in the torque fluctuation is small. In the third invention, the engine institutional cycle in the torque fluctuation at the time of low speed operation is reduced.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG.
a. Each cylinder 1a is connected to a common surge tank 3 via a corresponding intake branch pipe 2. The surge tank 3 is connected to an air cleaner 5 via an intake duct 4. A throttle valve 7 driven by a step motor 6 is arranged in the intake duct 4. The throttle valve 7 is closed to some extent only when the engine load is extremely low, and is kept fully open when the engine load is slightly increased. On the other hand, each cylinder 1 a is connected to a common exhaust manifold 8, and this exhaust manifold 8 is connected to a three-way catalytic converter 9. Further, each cylinder 1a is provided with an in-cylinder injection fuel injection valve 11 for injecting fuel into the cylinder and an intake port injection fuel injection valve 12 for injecting fuel into the intake port. Each cylinder 1a is provided with two fuel injections 11 and 12, respectively. These fuel injection valves 11 and 12 are controlled based on output signals of the electronic control unit 30, respectively.

As shown in FIG. 1, the engine body 1 is connected to an automatic transmission 13. The automatic transmission 13 includes, for example, a fluid torque converter 14 as shown in FIG.
Referring to FIG. 2, reference numeral 15 denotes a torque converter input shaft connected to a crankshaft (not shown), 16 denotes a torque converter output shaft, and 17 denotes a torque converter input shaft 1.
Reference numeral 5 denotes a pump impeller connected to 5, 5 denotes a turbine impeller connected to the torque converter output shaft 16, and 19 denotes a stator impeller. Further, the torque converter 14 includes a lock-up clutch 20 for directly connecting the torque converter input shaft 15 and the torque converter output shaft 16, that is, for locking up. The lock-up clutch 20 is driven by a hydraulic pressure difference between the pair of hydraulic oil chambers 21 and 22, and the hydraulic pressure in the hydraulic oil chambers 21 and 22 is controlled by, for example, an oil pump (not shown). When the hydraulic pressure in the hydraulic oil chamber 21 is higher than the hydraulic pressure in the hydraulic oil chamber 22, the lock-up clutch 20 and the torque converter input shaft 15 are engaged as shown in FIG. The input shaft 15 and the torque converter output shaft 16 are directly connected, that is, locked up. On the other hand, the hydraulic pressure in the hydraulic oil chamber 22 is
When the pressure is higher than the oil pressure inside the lock-up clutch 20 and the torque converter input shaft 15 as shown in FIG.
Are not engaged, so that lock-up is not performed. In this case, power transmission from the torque converter input shaft 15 to the torque converter output shaft 16 is performed via hydraulic oil flowing in the pump impeller 17, the turbine impeller 18, and the stator impeller 19. The automatic transmission 13 is controlled based on an output signal of the electronic control unit 30.

In the embodiment shown in FIG. 1, it is determined whether or not the lockup should be performed based on the map shown in FIG. 4, that is, depending on the vehicle speed V and the engine load, for example, the depression amount L of the accelerator pedal 10 (FIG. 1). Is determined. The map shown in FIG. 4 is stored in the ROM 33 in advance.

Referring again to FIG. 1, the electronic control unit 30 comprises a digital computer and a bidirectional bus 31.
(Read only memory) 32, RAM (random access memory) 33, C
A PU (microprocessor) 34, an input port 35 and an output port 36 are provided. The accelerator pedal 10 is connected to a load sensor 37 that generates an output voltage proportional to the amount of depression of the accelerator pedal 10, and the output voltage of the load sensor 37 is input to an input port 35 via an AD converter 38. The input port 35 is connected to a rotation speed sensor 39 that generates an output pulse indicating the engine rotation speed. Further, a speed sensor 40 for generating an output pulse representing the vehicle speed is connected to the input port 35. On the other hand, output port 3
6 is a stepping motor 6 via a corresponding driving circuit 41,
The in-cylinder fuel injection valves 11, the intake port injection fuel injection valves 12, and the automatic transmission 13 are connected to each other.

FIG. 5 shows a combustion chamber structure of each cylinder 1a. Referring to FIG. 5A, reference numeral 50 denotes a cylinder block, 51 denotes a piston reciprocating in the cylinder block 50, 52 denotes a cylinder head fixed on the cylinder block 50, and 53 denotes a portion formed between the piston 51 and the cylinder head 52. Combustion chamber, 54 is an intake valve, 55 is an exhaust valve, 5
6 indicates an intake port, 57 indicates an exhaust port, and 58 indicates a spark plug. The intake port 56 is configured such that the air flowing into the combustion chamber 53 generates a swirling flow around the cylinder axis. The fuel injected from the in-cylinder injection fuel injection valve 11 or the intake port injection fuel injection valve 12 is diffused while being vaporized by the swirling flow. FIG.
As shown in (B), a shallow plate portion 59 having a substantially circular contour extending from below the in-cylinder fuel injection valve 11 to below the spark plug 58 is formed on the top surface of the piston 51, and is shallow. A deep dish portion 60 having a substantially hemispherical shape is formed at the center of the dish portion 59. A substantially spherical concave portion 61 is formed at a connection portion of the shallow plate portion 59 located below the ignition plug 58 and the deep plate portion 60.

FIG. 6 shows a fuel supply method when the intake port injection is performed, and FIG. 7 shows a fuel supply method when the in-cylinder injection is performed. In the embodiment shown in FIG. 1, either the intake port injection or the in-cylinder injection is performed in principle depending on the engine speed N and the depression amount L of the accelerator pedal 10, as shown in FIG. In FIG. 8, a third region is provided between a region in which the intake port injection is to be performed and a region in which the in-cylinder injection is to be performed. In the third region, a part of the required fuel amount is supplied to the engine by the intake port injection. At the same time, the remaining fuel may be supplied to the engine by in-cylinder injection. When the engine operation state is in the region where the intake port injection is to be performed in FIG. 8, fuel injection F is performed from the intake port injection fuel injection valve 12 into the intake port 56 at the beginning of the engine intake stroke as shown in FIG. .
Next, air is sucked in through the intake valve 54, and as a result, the fuel is diffused while being vaporized by the swirling flow S, so that the inside of the combustion chamber 53 is almost uniformly filled with the air-fuel mixture. This mixture is ignited by an ignition plug 58. When the intake port injection is being performed by the intake port injection fuel injection valve 12, the fuel injection from the in-cylinder injection fuel injection valve 11 is stopped. On the other hand, when the engine operating state is in the region where in-cylinder injection is to be performed in FIG. 8, as shown in FIG. The fuel injection F is performed toward the recess, whereby an air-fuel mixture is formed in the concave portion 61 and the deep dish portion 60. At this time, the inside of the combustion chamber 53 other than the concave portion 61 and the deep dish portion 60 is filled with air. The mixture is then ignited by a spark plug 58.
When in-cylinder injection is being performed by the in-cylinder fuel injection valve 11, fuel injection from the intake port injection fuel injection valve 12 is stopped.

When the in-cylinder injection is performed, that is, when the air-fuel mixture is formed in the concave portion 61 and the deep dish portion 60 and the other combustion chamber 53 is filled with air, the same engine output is obtained. Since the required amount of air is larger than when the intake port injection is performed, the maximum combustion pressure in the combustion chamber 53 is increased. When the in-cylinder injection is performed, the combustion speed of the air-fuel mixture in the combustion chamber 53 is increased. As a result, when the in-cylinder injection is performed, the torque fluctuation in the engine cycle is larger than when the intake port injection is performed. However, when in-cylinder injection is performed in the lock-up state, that is, when the torque converter input shaft 15 and the torque converter output shaft 16 are directly connected as shown in FIG. As described above, the torque fluctuation in the cycle is large, so that the vehicle vibration is increased and a muffled sound is generated. In particular, when the vehicle speed is low, the vehicle vibration is further increased, and the muffled sound is relatively louder than the running sound or the wind noise, and becomes unpleasant noise. Therefore, in the embodiment shown in FIG.
According to the map, even if the operation state is in-cylinder injection, lock-up (lock-up state ) occurs and intake port injection is performed when the vehicle speed V is equal to or lower than a predetermined set speed V1 (FIG. 4). I am trying to do it. In the present embodiment, the set speed V1 is determined to be a minimum speed at which vehicle vibration or muffled sound is not increased even when in-cylinder injection is performed while locking up. If intake port injection is performed when the vehicle is locked up and the vehicle speed V is equal to or lower than the set speed V1, torque fluctuation in the cycle can be reduced, so that vehicle vibration can be reduced even when the vehicle is locked up, and muffled noise can be reduced. On the other hand, based on the map of FIG. 8, in-cylinder injection is performed when lock-up is not performed when in-cylinder injection is to be performed, or when lock-up is performed and vehicle speed V is higher than set speed V1.

Next, a routine for executing the above embodiment will be described with reference to FIG. This routine is executed by interruption every predetermined period. FIG.
First, at step 70, it is determined whether or not to perform in-cylinder injection based on the map of FIG. When intake port injection is to be performed, the routine proceeds to step 73, where intake port injection is performed. On the other hand, when in-cylinder injection is to be performed, step 7
The program proceeds to 1 to determine whether or not the lock-up has been performed. Locked up (locked up
) , The process proceeds to a step 72, wherein it is determined whether or not the vehicle speed V is equal to or lower than a predetermined set speed V1. When V ≦ V1, the routine proceeds to step 73, where intake port injection is performed, and then the processing cycle ends. When lock-up is not performed in step 71, or when V> V1 in step 72, the process proceeds to step 74, and in-cylinder injection is performed. Next, the processing cycle ends.

In the above-described embodiment, lock-up is performed when the engine operating state is an operating state in which in-cylinder injection is to be performed, and switching from in-cylinder injection to intake port injection is performed when the vehicle speed V is equal to or lower than the set speed V1. . However, when lockup is performed regardless of the vehicle speed V, it may be switched from in-cylinder injection to intake port injection.

FIG. 10 shows another embodiment according to the first invention. In the embodiment shown in FIG. 10, the same components as those in FIG. 1 are indicated by the same numbers, and the electronic control unit 30 shown in FIG. 1 is omitted in FIG. FIG.
Referring to FIG. 0, an automatic transmission 13 similar to the embodiment shown in FIG. Further, the torque converter 14 provided in the automatic transmission 13 performs lock-up control based on the map of FIG. However, in the embodiment shown in FIG. 10, each cylinder 1a has only the in-cylinder fuel injection valve 11 for injecting fuel into the cylinder, and therefore each cylinder 1a has one fuel injection valve 11 each. Is provided.

FIG. 11 shows a fuel supply method when the intake stroke injection is performed, and FIG. 12 shows a fuel supply method when the compression stroke injection is performed. In the embodiment shown in FIG. 10, in principle, either the intake stroke injection or the compression stroke injection is performed depending on the engine speed N and the depression amount L of the accelerator pedal 10, as shown in FIG. FIG. 1
3, a third region is provided between a region in which the intake stroke injection is to be performed and a region in which the compression stroke injection is to be performed. In the third region, a part of the required fuel amount is supplied to the engine by the intake stroke injection and the remaining fuel amount is supplied to the engine. May be supplied to the engine by compression stroke injection. When the engine operating state is in the region where the intake stroke injection is to be performed in FIG. 13, the fuel injection F is directed from the in-cylinder fuel injection valve 11 toward the shallow plate portion 59 at the beginning of the engine intake stroke as shown in FIG.
Is performed. Next, air is sucked in through the intake valve 54, and as a result, the fuel is diffused while being vaporized by the swirling flow S, so that the inside of the combustion chamber 53 is almost uniformly filled with the air-fuel mixture. This mixture is ignited by an ignition plug 58. On the other hand, when the engine operating state is in the region where the compression stroke injection is to be performed in FIG. 13, the fuel injection valve 1 is at the end of the engine compression stroke as shown in FIG.
From 1, fuel injection F is performed toward the peripheral wall surface of the deep dish portion 60, whereby an air-fuel mixture is formed in the concave portion 61 and the deep dish portion 60. At this time, the inside of the combustion chamber 53 other than the concave portion 61 and the deep dish portion 60 is filled with air. The mixture is then ignited by a spark plug 58.

When the compression stroke injection is performed, that is, when the air-fuel mixture is formed in the concave portion 61 and the deep dish portion 60 and the other combustion chamber 53 is filled with air, the same engine output is obtained. The required amount of air is larger than when the intake stroke injection is performed, so that the maximum combustion pressure in the combustion chamber 53 increases. Further, when the compression stroke injection is performed, the combustion speed of the air-fuel mixture in the combustion chamber 53 is increased. As a result, when the compression stroke injection is performed, the torque fluctuation in the engine cycle is larger than when the intake stroke injection is performed. However,
If the compression stroke injection is performed when the lock-up is performed, at this time, since the in-cycle torque fluctuation is large as described above, the vehicle vibration is increased and a muffled sound is generated. In particular, when the vehicle speed is low, the vehicle vibration is further increased, and the muffled sound is relatively louder than the running sound or the wind noise, and becomes unpleasant noise. Therefore, in the embodiment shown in FIG. 10, even if the engine operating state is the operating state in which in-cylinder injection is to be performed based on the map of FIG.
1 (FIG. 4) or less, the intake stroke injection is performed. In the present embodiment, the set speed V1 is determined to be a minimum speed at which vehicle vibration or muffled noise is not increased even when the compression stroke injection is performed while locking up. If the intake stroke injection is performed when the vehicle is locked up and the vehicle speed V is equal to or less than the set speed V1, the torque fluctuation in the cycle can be reduced. Therefore, even when the vehicle is locked up, the vehicle vibration can be reduced and the muffled noise can be reduced. On the other hand, based on the map of FIG. 13, the compression stroke injection is performed when the lockup is not performed when the compression stroke injection is to be performed, or when the lockup is performed and the vehicle speed V is higher than the set speed V1.

Next, a routine for executing the above-described embodiment will be described with reference to FIG. This routine is executed by interruption every predetermined period. Referring to FIG. 14, first, at step 80, it is determined whether or not to perform the compression stroke injection based on the map of FIG.
When the intake stroke injection is to be performed, the routine proceeds to step 83, where the intake stroke injection is performed. On the other hand, when the compression stroke is to be injected, the routine proceeds to step 81, where it is determined whether or not the lock-up has been performed. When the vehicle is locked up, the routine proceeds to step 82, where the vehicle speed V is set to a predetermined set speed V1.
It is determined whether or not: When V ≦ V1, the routine proceeds to step 83, where the intake stroke injection is performed, and then the processing cycle ends. When it is not locked up in step 81, or when V is
If> V1, the routine proceeds to step 84, where compression stroke injection is performed. Next, the processing cycle ends.

In the above-described embodiment, the lock-up is performed when the engine operation state is the operation state in which the compression stroke injection is to be performed, and when the vehicle speed V is equal to or lower than the set speed V1, the injection is switched from the compression stroke injection to the intake stroke injection. . However, when the lockup is performed regardless of the vehicle speed V, the injection may be switched from the compression stroke injection to the intake stroke injection.

Next, an embodiment according to the second invention will be described.
In this embodiment, the internal combustion engine is constructed in the same manner as the embodiment shown in FIG. 1. Therefore, each cylinder 1a has two fuel injection valves 11, an in-cylinder fuel injection valve 11 and an intake port injection fuel injection valve 12.
A number of fuel injection valves are provided. Also in the present embodiment, one of the intake port injection and the in-cylinder injection is performed based on the map shown in FIG. That is, when intake port injection is to be performed, fuel is injected into the intake port 56 from the intake port injection fuel injection valve 12 at the beginning of the intake stroke as shown in FIG. To be filled. On the other hand, when in-cylinder injection is to be performed, fuel is injected from the in-cylinder fuel injection valve 11 into the deep dish portion 60 at the end of the compression stroke as shown in FIG. Air is formed and the inside of the combustion chamber 53 other than the concave portion 61 and the deep dish portion 60 is filled with air. Further, an automatic transmission 13 similar to the embodiment shown in FIG. 1 is connected to the engine body 1, and the automatic transmission 13 performs lockup control based on an output signal of the electronic control unit 30.

Incidentally, when in-cylinder injection is being performed, the torque fluctuation in the engine cycle is large as described above. Therefore, during low-speed operation of the engine, the vehicle vibration is increased and a muffled sound is generated. Particularly when the automatic transmission 13 capable of lock-up is provided as in the present embodiment, if the lock-up is performed while performing in-cylinder injection, the vehicle vibration is further increased and the muffled noise is increased. on the other hand,
When intake port injection is being performed, the torque fluctuation in the cycle is relatively small, so even if lockup occurs when the vehicle speed is relatively low, the effect on vehicle vibration and muffled noise is small. Therefore, in the present embodiment, a map for lockup control based on when the intake port injection is performed as shown in FIG. 15A and the in-cylinder injection as shown in FIG. 15B are performed. A map for lock-up control based on time is provided, and in these maps, a region to be locked up during in-cylinder injection is provided on a higher speed side than a region to be locked up during intake port injection. For example, in the case where the engine operation state is the operation state at the point D shown in FIG.
Lock-up is prevented based on the map of (B), and as a result, vehicle vibration and muffled sound can be reduced. On the other hand, when the engine operation state is the operation state at the point D, the lock-up is performed based on FIG. 15A when the intake port injection is being performed, but at this time, the vehicle vibration and the muffled sound are reduced as described above. The effect is smaller.

Next, a routine for executing the above-described embodiment will be described with reference to FIG. This routine is executed by interruption every predetermined period. Referring to FIG. 16, first, in step 90, it is determined whether or not in-cylinder injection is currently being performed. In the present embodiment, whether or not to perform in-cylinder injection is determined in advance by a routine (not shown) based on the map of FIG. When the in-cylinder injection is being performed, the routine proceeds to step 91, where it is determined based on FIG. 15B whether or not the lockup should be performed. On the other hand, when the intake port injection is being performed, the routine proceeds to step 92, where it is determined based on FIG. If it is determined in step 91 or 92 that the lockup is to be performed, the flow advances to step 93 to lock up. Next, the processing cycle ends. Step 91
Alternatively, if it is determined in step 92 that the lockup should not be performed, the process proceeds to step 94 without locking up, and then the processing cycle is ended.

In the above-described embodiment, the determination based on the map shown in FIG. 8, that is, the determination as to which of the in-cylinder injection and the intake port injection is to be performed is ensured irrespective of whether or not the lockup should be performed. The map in FIG. 8 is set, for example, to improve the engine fuel efficiency. Therefore, in this embodiment, it is possible to reduce the vehicle vibration and the muffled noise while ensuring the improvement in the engine fuel efficiency.

Next, another embodiment according to the second invention will be described. In this embodiment, the internal combustion engine is configured in the same manner as the embodiment shown in FIG. 10, so that each cylinder 1a is provided with only the in-cylinder fuel injection valve 11. Also in the present embodiment, one of the intake stroke injection and the compression stroke injection is performed based on the map shown in FIG. That is, when the intake stroke is to be injected, fuel is injected into the shallow plate portion 59 at the beginning of the intake stroke as shown in FIG. 11, so that the combustion chamber 53 is filled with a substantially uniform mixture. On the other hand, when the compression stroke is to be injected, fuel is injected into the deep dish portion 60 at the end of the compression stroke as shown in FIG. The inside of the combustion chamber 53 other than the plate portion 60 is filled with air. Further, an automatic transmission 13 similar to the embodiment shown in FIG. 10 is connected to the engine main body 1, and the automatic transmission 13 performs lockup control based on an output signal of the electronic control unit 30.

By the way, when the compression stroke injection is being performed, the torque fluctuation in the engine cycle is large as described above, so that the vehicle vibration is increased and the muffled sound is generated at the time of the engine low speed operation. In particular, when the automatic transmission 13 capable of lock-up is provided as in the present embodiment, if the lock-up is performed while performing the compression stroke injection, the vehicle vibration is further increased and the booming noise is also increased. On the other hand, when the intake stroke injection is being performed, the torque fluctuation in the cycle is relatively small, so even if the vehicle locks up when the vehicle speed is relatively low, the influence on the vehicle vibration and the muffled sound is small. Therefore, in this embodiment, a map for lockup control based on when the intake stroke injection is performed as shown in FIG. 17A and the compression stroke injection as shown in FIG. 17B are performed. A map for lock-up control based on the time is provided, and in these maps, a region to be locked up during the compression stroke injection is provided on a higher speed side than a region to be locked up during the intake stroke injection. For example, when the engine operating state is the operating state at the point D shown in FIG. 17, if the compression stroke injection is being performed, the lock-up is prevented based on the map of FIG. 17B, and as a result, the vehicle vibration and the muffled sound Can be reduced. On the other hand, when the engine operation state is the operation state at the point D and the intake stroke injection is being performed, FIG.
The lockup is performed based on (A), but at this time, the influence on the vehicle vibration and the muffled sound is reduced as described above.

Next, a routine for executing the above-described embodiment will be described with reference to FIG. This routine is executed by interruption every predetermined period. Referring to FIG. 18, first, at step 100, it is determined whether or not the compression stroke injection is currently being performed. In the present embodiment, whether or not to perform the compression stroke injection is determined in advance by a routine (not shown) based on the map of FIG. When the compression stroke injection is being performed, the routine proceeds to step 101, where it is determined based on FIG. 17B whether or not the lockup should be performed. On the other hand, when the intake stroke injection is being performed, the routine proceeds to step 102, where it is determined based on FIG. Step 101 or step 102
When it is determined that the lockup should be performed, the process proceeds to step 103 to lock up. Next, the processing cycle ends. On the other hand, step 101 or step 102
If you should not lock up in step 1
In step 04, the lockup is not performed, and then the processing cycle ends.

In the above-described embodiment, the determination based on the map shown in FIG. 13, that is, the determination as to whether to perform the compression stroke injection or the intake stroke injection, is ensured irrespective of whether or not the lockup should be performed. The map in FIG. 13 is set, for example, to improve the engine fuel efficiency. Therefore, in the present embodiment, it is possible to reduce the vehicle vibration and the muffled sound while ensuring the improvement in the engine fuel efficiency.

Next, an embodiment according to the third invention will be described.
In this embodiment, the internal combustion engine is constructed in the same manner as the embodiment shown in FIG. 1. Therefore, each cylinder 1a has two fuel injection valves 11, an in-cylinder fuel injection valve 11 and an intake port injection fuel injection valve 12.
A number of fuel injection valves are provided. In the present embodiment, in principle, one of the intake port injection and the in-cylinder injection is performed based on the map shown in FIG. However, the automatic transmission 13 as shown in FIG. 1 may not be connected to the engine main body 1, that is, a manual transmission may be connected to the engine main body 1.

As described above, when the in-cylinder injection is performed during the low-speed operation of the engine, the vehicle vibration and the muffled noise increase because the torque fluctuation in the engine cycle is larger in this case than when the intake port injection is performed. Can be done. Further, for example, when the engine speed is low, such as during idling, the torque reaction force is particularly easily transmitted from the engine mount to the vehicle. Therefore, if in-cylinder injection is performed at this time, vehicle vibration and booming noise may increase. Furthermore, when an automatic transmission is connected to the engine body 1, the automatic transmission usually does not have a flywheel, for example, for keeping the rotation speed of the output shaft constant. The vehicle vibration and the muffled sound may be increased as compared with the case where the machines are connected. Therefore, in the present embodiment, based on the map of FIG. 19, the vehicle speed V is equal to or lower than the predetermined set speed V1 and the engine speed N is predetermined. When the rotational speed is equal to or lower than the set rotational speed N1 (FIG. 19), the intake port injection is performed. In the present embodiment, the set speed V1 is determined to be a minimum speed at which vehicle vibration or muffled noise is not increased even when in-cylinder injection is performed. The set rotation speed N1 is set when the vehicle speed V is equal to or less than the set speed V1. The rotation speed is determined to be the minimum rotation speed at which vehicle vibration or muffled noise is not increased even when in-cylinder injection is performed. If the intake port injection is performed when the vehicle speed V is equal to or less than the set speed V1 and the engine speed N is equal to or less than the set speed N1, the torque fluctuation in the cycle can be reduced, so that the vehicle vibration and the muffled sound can be reduced. Further, even when an automatic transmission is connected to the engine body 1, vehicle vibration and muffled noise can be reduced. When a manual transmission having a flywheel is connected, vehicle vibration and muffled noise can be further reduced. On the other hand, FIG.
According to the map, in-cylinder injection is performed when the vehicle speed V is higher than the set speed V1 or when the engine speed N is higher than the set speed N1 when in-cylinder injection is to be performed.

Next, a routine for executing the above-described embodiment will be described with reference to FIG. This routine is executed by interruption every predetermined period. Referring to FIG. 20, first, at step 110, FIG.
It is determined whether or not to perform in-cylinder injection based on the map of No. 9. When intake port injection is to be performed, the routine proceeds to step 113, where intake port injection is performed. On the other hand, when in-cylinder injection is to be performed, the routine proceeds to step 111, where it is determined whether or not the vehicle speed V is equal to or lower than a predetermined set speed V1. V ≦
In the case of V1, the routine proceeds to step 112, where it is determined whether or not the vehicle rotation speed N is equal to or lower than a predetermined rotation speed N1. When N ≦ N1, the routine proceeds to step 113, where intake port injection is performed, and then the processing cycle ends. If V> V1 in step 111, or if N> N1 in step 112, step 1
Proceeding to 14, the in-cylinder injection is performed. Next, the processing cycle ends.

In the above-described embodiment, when the engine operating state is an operating state in which in-cylinder injection is to be performed, the vehicle speed V is set to the set speed V1
When the engine speed N is equal to or less than the set engine speed N1, the mode is switched from in-cylinder injection to intake port injection. However, when the vehicle speed V is equal to or lower than the set speed V1 regardless of the engine speed N, the injection may be switched from the in-cylinder injection to the intake port injection.

Next, another embodiment according to the third invention will be described. In this embodiment, the internal combustion engine is configured in the same manner as the embodiment shown in FIG. 10, so that each cylinder 1a is provided with only the in-cylinder fuel injection valve 11. In this embodiment,
In principle, one of the intake stroke injection and the compression stroke injection is performed based on the map shown in FIG. However, the automatic transmission 13 as shown in FIG. 1 does not need to be connected to the engine main body 1, that is, a manual transmission may be connected to the engine main body 1.

As described above, when the compression stroke injection is performed during the low-speed operation of the engine, the vehicle vibration and the booming noise increase because the torque fluctuation in the engine cycle is larger than in the case where the intake stroke injection is performed. Can be done. Further, for example, when the engine speed is low such as during idling, the torque reaction force is particularly easily transmitted from the engine mount to the vehicle. Therefore, if the compression stroke injection is performed at this time, the vehicle vibration and the muffled sound may increase. Furthermore, when an automatic transmission is connected to the engine body 1, the automatic transmission usually does not have a flywheel, for example, for keeping the rotation speed of the output shaft constant. The vehicle vibration and the muffled sound may be increased as compared with the case where the machines are connected. Therefore, in this embodiment, based on the map of FIG. 21, the vehicle speed V is equal to or lower than the predetermined set speed V1 and the engine speed N is predetermined even if the engine operation state is the operation state in which the compression stroke is to be injected. When the rotation speed is equal to or lower than the set rotation speed N1 (FIG. 21), the intake stroke injection is performed. In this embodiment, the set speed V
1 is set so as to be a minimum speed at which vehicle vibration or muffled sound is not increased even when compression stroke injection is performed. Also, when the vehicle speed V is equal to or lower than the set speed V1, the compression stroke injection is performed. However, the rotation speed is set to be the minimum rotation speed at which vehicle vibration or muffled sound is not increased. When the intake stroke injection is performed when the vehicle speed V is equal to or lower than the set speed V1 and the engine speed N is equal to or lower than the set speed N1, the fluctuation in the in-cycle torque can be reduced, so that the vehicle vibration and the muffled sound can be reduced. Further, even when an automatic transmission is connected to the engine body 1, vehicle vibration and muffled noise can be reduced. When a manual transmission having a flywheel is connected, vehicle vibration and muffled noise can be further reduced. On the other hand, based on the map shown in FIG. 21, when the compression stroke injection is to be performed, the compression stroke injection is performed when the vehicle speed V is higher than the set speed V1 or when the engine speed N is higher than the set rotation speed N1.

Next, a routine for executing the above-described embodiment will be described with reference to FIG. This routine is executed by interruption every predetermined period. Referring to FIG. 22, first, in step 120, FIG.
It is determined on the basis of the first map whether or not the compression stroke should be injected. When the intake stroke injection is to be performed, the routine proceeds to step 123, where the intake stroke injection is performed. On the other hand, when the compression stroke is to be injected, the routine proceeds to step 121, where it is determined whether or not the vehicle speed V is equal to or lower than a predetermined set speed V1.
When V ≦ V1, the routine proceeds to step 122, where it is determined whether or not the vehicle rotation speed N is equal to or less than a predetermined rotation speed N1. When N ≦ N1, the routine proceeds to step 123, where the intake stroke injection is performed, and then the processing cycle ends. If V> V1 in step 121 or N> N1 in step 122, step 1
Proceeding to 24, compression stroke injection is performed. Next, the processing cycle ends.

In the above-described embodiment, when the vehicle speed V is equal to or lower than the set speed V1 and the engine speed N is equal to or lower than the set speed N1 when the engine operation state is the operation state in which the compression stroke injection is to be performed, the compression stroke injection is started. The mode is switched to the intake stroke injection. However, when the vehicle speed V is equal to or lower than the set speed V1 regardless of the engine speed N, the injection may be switched from the compression stroke injection to the intake stroke injection.

According to the embodiments described above, vehicle vibration or muffled noise can be reduced without using, for example, a flywheel damper or a variable engine mound, thereby preventing the structure from becoming complicated. And prevent the vehicle from becoming expensive.

[0037]

According to the present invention it is possible to reduce the car both vibration and booming noise.

[Brief description of the drawings]

FIG. 1 is an overall view of an internal combustion engine according to a first invention.

FIG. 2 is a partial side sectional view of the torque converter.

FIG. 3 is a partial side sectional view of a torque converter illustrating lock-up control;

FIG. 4 is a diagram showing an operation state to be locked up.

FIG. 5 is a side sectional view of the internal combustion engine.

FIG. 6 is a side sectional view of the internal combustion engine illustrating intake port injection.

FIG. 7 is a side sectional view of the internal combustion engine illustrating in-cylinder injection.

FIG. 8 is a diagram illustrating a method of supplying fuel to an engine.

FIG. 9 is a flowchart for executing fuel injection control.

FIG. 10 is an overall view of an internal combustion engine according to another embodiment of the first invention.

FIG. 11 is a side sectional view of the internal combustion engine illustrating intake stroke injection.

FIG. 12 is a side sectional view of the internal combustion engine illustrating compression stroke injection.

FIG. 13 is a diagram illustrating a method of supplying fuel to an engine.

FIG. 14 is a flowchart for executing fuel injection control.

FIG. 15 is a diagram showing an operation state to be locked up.

FIG. 16 is a flowchart for executing lock-up control.

FIG. 17 is a diagram showing an operation state to be locked up.

FIG. 18 is a flowchart for executing lock-up control.

FIG. 19 is a diagram illustrating a method of supplying fuel to an engine.

FIG. 20 is a flowchart for executing fuel injection control.

FIG. 21 is a diagram illustrating a method of supplying fuel to an engine.

FIG. 22 is a flowchart for executing fuel injection control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... In-cylinder injection fuel injection valve 12 ... Intake port injection fuel injection valve 13 ... Automatic transmission 14 ... Torque converter 20 ... Lock-up clutch 53 ... Combustion chamber 56 ... Intake port

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁷ Identification code FI F16H 61/14 601 F16H 61/14 601 (56) References JP-A-4-224245 (JP, A) JP-A-2-259272 (JP, A) JP-A-4-39131 (JP, A) JP-A-5-240072 (JP, A) JP-A-4-237854 (JP, A) JP-A-3-277863 (JP, A) 60-6024836 (JP, U) Actually open 58-137843 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 41/00-41/40 F02D 43/00- 45/00 F02D 29/00-29/06 B60K 41/00-41/28 F02B 15/00 F16H 61/14

Claims (3)

(57) [Claims] 1. Mixing only in a limited area within the combustion chamber
Gas is formed, and the mixture is ignited by an ignition plug to burn
The stratified combustion that burns and the mixture that fills the entire combustion chamber
Switching between homogeneous combustion, which forms and burns the mixture
And combustion control means capable, in an internal combustion engine having a power transmission means capable of locking up, it in Russia Kkuappu state
Internal combustion engine to perform homogeneous combustion in Ttei Rutoki. 2. Mixing only in a limited area within the combustion chamber
Gas is formed, and the mixture is ignited by an ignition plug to burn
The stratified combustion that burns and the mixture that fills the entire combustion chamber
Switching between homogeneous combustion, which forms and burns the mixture
In an internal combustion engine equipped with possible combustion control means and lockable power transmission means, homogeneous combustion should be performed.
When the vehicle speed is higher than the first set speed, the lock-up state is maintained, and when stratified combustion is to be performed , the vehicle speed is higher than the second set speed higher than the first set speed. An internal combustion engine that is sometimes kept in a lock-up state . 3. Mixing only in a limited area within the combustion chamber
Gas is formed, and the mixture is ignited by an ignition plug to burn
The stratified combustion that burns and the mixture that fills the entire combustion chamber
Switching between homogeneous combustion, which forms and burns the mixture
In an internal combustion engine having a combustion control means capable, homogeneous combustion when the car both speed is below the set speed to a predetermined
Internal combustion engine to do .