JP2005083233A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent degradation of response caused by delay in supply of intake air to a combustion chamber to improve driveability, in a control device of an internal combustion engine. <P>SOLUTION: An air assist injector 24 for supplying secondary air together with fuel to a combustion chamber is disposed to an intake pipe with throttle valve 34 for supplying primary air to the combustion chamber 17. When supply of the primary air to the combustion chamber through the intake pipe 22 is delayed, such as in acceleration of an engine, amount of secondary air supply by the air assist injector 24 is increased. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control device for an internal combustion engine that efficiently introduces a predetermined amount of air and fuel into a combustion chamber without delay.

  In a general internal combustion engine, the fuel injection amount is set based on the intake air amount and the engine speed, and in the intake stroke, the air-fuel mixture that has been set to the target air-fuel ratio by opening the intake valve burns In the compression stroke, the air-fuel mixture in the combustion chamber is compressed by the rise of the piston in the compression stroke, and in the combustion / expansion stroke, the air-fuel mixture is ignited, burned and expanded as a high-temperature gas, Heat energy is efficiently converted into kinetic energy, and the internal combustion engine can obtain a predetermined torque. On the other hand, in the exhaust stroke, gas generated by combustion is exhausted by opening an exhaust valve. When the driver makes an acceleration request by depressing the accelerator pedal, the throttle opening increases and the intake air amount increases. As the intake air amount increases, the fuel injection amount increases and the output torque increases. Will increase.

As a conventional fuel injection device for an internal combustion engine, there is Patent Document 1 below.
JP-A-6-026425

  However, in the above-described conventional internal combustion engine, when the driver depresses the accelerator pedal, the throttle opening increases, the intake air amount increases, and the fuel injection amount increases in accordance with the increased intake air amount. However, there is a time delay until the increased air is introduced into the combustion chamber, and the response to the driver's acceleration request is not good. That is, even if the driver depresses the accelerator pedal and the throttle opening suddenly increases, there is a time delay until the increased amount of air is introduced from the intake passage into the combustion chamber through the throttle valve. The amount of intake air introduced into the combustion chamber does not increase rapidly but increases gradually. Therefore, since the fuel injection amount is also increased according to the gradually increasing intake air amount, the output torque is also gradually increased. Therefore, even if the driver requests acceleration that depresses the accelerator pedal suddenly, the output torque does not immediately increase, the acceleration response is not good, and the drivability is deteriorated.

  In the “fuel injection device for an internal combustion engine” described in Patent Document 1 described above, one end of the air introduction passage is connected to the intake pipe upstream of the throttle valve, and the other end is provided downstream of the throttle valve. When the internal combustion engine is accelerated, an optimal fuel amount is calculated based on the intake air amount detected by the air amount sensor, and this fuel is injected from the fuel injection valve. The air flow generated by the differential pressure with the upstream of the throttle valve collides with the fuel spray in the vicinity of the injection port through the atmosphere introduction passage, thereby enabling the atomization of the fuel. However, even if an air introduction passage that bypasses the throttle valve is provided as in this device, the introduction delay of the intake air that accompanies the opening operation of the throttle valve cannot be prevented.

  The present invention solves such problems, and provides a control device for an internal combustion engine that improves drivability by preventing deterioration in response due to a delay in supply of intake air to a combustion chamber. For the purpose.

  In order to achieve the above object, a control apparatus for an internal combustion engine according to claim 1 of the present invention includes primary air supply means for supplying primary air to a combustion chamber through an intake passage, and fuel is injected into the intake passage or the combustion chamber. A delay occurs in the supply of primary air to the combustion chamber by the fuel injection means, secondary air supply means for supplying secondary air to the combustion chamber or the intake passage in the vicinity of the combustion chamber, and the primary air supply means. And a control means for correcting the amount of secondary air supplied by the secondary air supply means.

  In the control apparatus for an internal combustion engine according to the second aspect of the present invention, accelerator opening detection means for detecting the accelerator opening is provided, and when the amount of change in the accelerator opening is greater than or equal to a preset value, It is characterized by correcting the amount of secondary air supplied by the secondary air supply means.

  According to a third aspect of the present invention, there is provided a control device for an internal combustion engine, wherein the control means is a fuel injection means based on an intake air amount obtained by combining the supply amount of the primary air and the supply amount of the secondary air and the engine speed. It is characterized by controlling the fuel injection amount by.

  In a control apparatus for an internal combustion engine according to a fourth aspect of the invention, the fuel injection means and the secondary air supply means are air assist injectors for injecting fuel together with compressed air.

  According to the control apparatus for an internal combustion engine of the first aspect of the present invention, when a supply delay of the primary air supplied to the combustion chamber through the intake passage occurs, the secondary air supplied directly to the combustion chamber or the intake passage in the vicinity thereof is reduced. Since the supply amount is corrected, if the intake air is insufficient or excessive due to a delay in the supply of primary air supplied to the combustion chamber through the intake passage during acceleration / deceleration of the vehicle accompanying the driver's accelerator operation, supply of secondary air The amount is corrected, that is, increased or decreased, and supplied to the combustion chamber or the intake passage, so that response deterioration due to a delay in supply of intake air to the combustion chamber can be prevented and drivability can be improved. .

  According to the control device for an internal combustion engine of the second aspect of the invention, when the amount of change in the accelerator opening is equal to or greater than a preset value, the supply amount of the secondary air is corrected. When the amount of change exceeds the set value, it means that the driver has requested acceleration.In this case, increasing the secondary air supply amount will increase the engine output as required by the driver. can do.

  According to the control apparatus for an internal combustion engine of the third aspect of the invention, the fuel injection amount set based on the intake air amount obtained by combining the primary air supply amount and the secondary air supply amount and the engine rotational speed is injected. Therefore, the engine output can be increased according to the driver's acceleration request by securing the fuel amount corresponding to the air amount.

  According to the control device for an internal combustion engine of the fourth aspect of the invention, since the air assist injector having both the fuel injection function and the secondary air supply function is employed, the device can be simplified and the manufacturing cost can be reduced. Can do.

  The best mode for carrying out the control device for an internal combustion engine according to the present invention is capable of supplying primary air to the combustion chamber through the intake passage and also supplying secondary air to the combustion chamber or the intake passage in the vicinity thereof. When there is a delay in the supply of primary air to the combustion chamber, the amount of secondary air supplied can be increased or decreased to quickly supply the amount of air and fuel suitable for the desired acceleration / deceleration. In the following, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram of an internal combustion engine control device according to an embodiment of the present invention, FIG. 2 is a flowchart of control by the internal combustion engine control device of the present embodiment, and FIG. 3 is an internal combustion engine control device of the present embodiment. The time chart of control is shown.

  In the control apparatus for an internal combustion engine of this embodiment, as shown in FIG. 1, an engine 11 mounted on a vehicle is a spark ignition gasoline engine, and a cylinder head 13 is fastened on a cylinder block 12, and this cylinder block 12, a plurality of pistons 14 are arranged in series, and are fitted so as to be movable up and down. A crankshaft 15 is rotatably supported at the lower portion of the cylinder block 12, and the crankshaft 15 and each piston 14 are connected by a connecting rod 16.

  A plurality of combustion chambers 17 are constituted by the cylinder block 12, the cylinder head 13, and each piston 14. An intake port 18 and an exhaust port 19 are communicated with both sides of each combustion chamber 17. The exhaust port 19 faces the leading ends of the intake valve 20 and the exhaust valve 21 so that the combustion chamber 17 and the ports 18 and 19 can be opened and closed. The intake port 18 is connected to an intake pipe 22 via an intake manifold, and the exhaust port 19 is connected to an exhaust manifold exhaust pipe 23.

  Each intake pipe 22 is provided with an air assist injector (fuel injection means, secondary air supply means) 24 for each cylinder, and a spark plug 25 is attached to the cylinder head 13. This air assist injector 24 injects compressed air to the injected fuel spray to atomize the fuel and prevent wall surface adhesion. Therefore, a fuel pump 27 and a fuel tank 28 are connected to the air assist injector 24 via a fuel pipe 26, and an accumulator 30 and a compressor 31 are connected via an assist air pipe 29. Although not shown, the internal structure of the air assist injector 24 includes a storage chamber for accumulating a predetermined amount of fuel sent from the fuel pipe 26 and an injection valve for opening and closing the mouth, and an assist air pipe 29. And an open / close valve that communicates with the shed. Accordingly, the air assist injector 24 opens the injection valve for a predetermined time to inject a predetermined amount of fuel, and simultaneously opens the on-off valve for a predetermined time to inject assist air toward the fuel spray, thereby It can be atomized and injected into the intake port 18.

  An air cleaner 32 is attached to the upstream end of the intake pipe 22, and a surge tank 33 is provided in the middle of the intake pipe 22. An electronic control throttle valve 34 is attached to the intake pipe 22 between the air cleaner 32 and the surge tank 33, and a throttle position sensor 35 for detecting the opening of the throttle valve 34 is attached. Yes. An air flow sensor 36 for detecting the intake air amount is attached upstream of the throttle valve 34.

  On the other hand, a catalyst device 37 is provided on the downstream side of the exhaust pipe 23. Further, the engine 11 is provided with a crank angle sensor 38 that outputs a crank angle signal at a predetermined crank position of each cylinder, and the crank angle sensor 38 can detect the engine speed (engine speed).

  The vehicle is provided with an engine electronic control unit (ECU) 39 for controlling the engine 11 and the like. The ECU 39 includes an input / output device, a storage device for storing a control program and a control map, a central processing unit, a timer, Counters are provided, and the ECU 39 performs overall control of the engine 11.

That is, the throttle opening θ _T detected by the throttle position sensor 35, the intake air amount Q _A1 detected by the air flow sensor 36, the engine speed Ne detected by the crank angle sensor 38, and the accelerator opening sensor 40 are detected. The engine opening state information such as the accelerator opening θ _A and the intake air temperature and the intake pressure are input to the ECU 39. The ECU 39 determines the ignition timing, the assist air amount Q _A2 (assist air injection time), etc. based on the operating state information such as the throttle opening θ _S , the intake air amount Q _A1 , the engine speed Ne, and the accelerator opening θ _A. Then, the spark plug 25, the throttle valve 34, etc. are driven and controlled.

In the control device for the internal combustion engine of this embodiment, the ECU 39 controls the fuel injection amount Q _F based on the in-cylinder supply air amount Q (Q _A1 + Q _A2 ) introduced into the combustion chamber 17 and the engine speed Ne. Is calculated, the driver 41 of the air assist injector 24 is driven and controlled, and the assist air amount Q _A2 is corrected based on the accelerator opening θ _A. When the engine 11 is in a substantially constant load state, the in-cylinder supply air amount Q is the amount of air introduced into the combustion chamber 17 through the throttle valve 34 of the intake pipe 22, that is, the intake air detected by the air flow sensor 36. Since the air amount (primary air amount) Q _A1 is substantially the same amount, the assist air amount (secondary air amount) Q _A2 injected to atomize the injected fuel from the air assist injector 24 is set in advance. Set to a very small amount. On the other hand, when the engine 11 changes greatly from the low load state to the high load state or from the high load state to the low load state, the intake air introduced into the combustion chamber 17 from the intake pipe 22 by the opening / closing timing of the slot valve 34. Since a supply delay occurs in the amount Q _A1 , the assist air amount Q _A2 injected from the air assist injector 24 is temporarily increased or decreased.

That is, even if the driver depresses the accelerator pedal and the throttle opening suddenly increases by θ _S , it takes time until the increased amount of air is introduced into the combustion chamber 17 from the intake pipe 22 through the throttle valve 34. The air amount Q introduced into the combustion chamber 17 does not increase abruptly and the fuel injection amount does not increase abruptly, so that an output torque corresponding to the driver's acceleration request can be obtained immediately. Can not. Therefore, in this embodiment, when the engine 11 is accelerated (decelerated), a delay amount of the air introduced from the intake pipe 22 is supplied from the air assist injector 24, so that the driver's acceleration request is obtained. The output torque corresponding to can be obtained immediately.

  Here, the control of the ECU 39 in the control apparatus for the internal combustion engine of the present embodiment described above will be described in detail based on the flowchart of FIG. 2 and the time chart of FIG.

As shown in FIG. 4, in step S11, the ECU 36 reads the accelerator opening θ _A detected by the accelerator opening sensor 40, and in step S12, the change amount A of the accelerator opening per predetermined time (predetermined cycle). _It is determined whether _D is equal to or greater than the set value A _S. If the accelerator opening change amount _AD is smaller than the set value A _{S in} step S12, it is determined that the engine load state has not changed greatly, and the process proceeds to step S13, where the intake air detected by the air flow sensor 36 is determined. An in-cylinder supply air amount Q is set based on the air amount Q _A1 and a preset assist air amount Q _A2, and a fuel injection amount Q _F is calculated based on the in-cylinder supply air amount Q and the engine speed Ne. The air assist injector 24 is driven and controlled by the driver 41 to inject a predetermined fuel injection amount Q _F. In step S14, the air assist injector 24 is driven and controlled by the driver 41 at the same time, and a predetermined assist air amount Q _A2 is injected. As a result, a predetermined amount of fuel is injected from the air assist injector 24 into the intake port 18, and at the same time, a small amount of assist air is injected into the injected fuel to atomize the fuel and air mixture. 17 is introduced.

On the other hand, at step S12, if the accelerator opening change amount A _D set value A _S above, determines that the driver is requesting acceleration by depressing the accelerator pedal, the engine load condition is changed greatly, step The process proceeds to S15. In this step S15, a correction example number K for setting the increase amount of the assist air supplied from the air assist injector 24 is calculated in order to supplement the increase delay of the intake air amount Q _{A1 with} respect to the driver's acceleration request. To do. Specifically, the assist correction coefficient K is calculated from the current engine speed Ne, the accelerator opening change amount _AD, and the function. In this case, a function map of the engine speed Ne and the accelerator opening change amount _AD may be set, and the assist air correction coefficient K may be obtained from this map.

In step S16, the assist air amount Q _A2 is corrected using the obtained assist air correction coefficient K. Specifically, it is corrected and set by multiplying the preset assist air injection time by this assist air correction coefficient K. In step S17, the cylinder supply air amount Q is set based on the intake air amount Q _A1 detected by the air flow sensor 36 and the assist air amount Q _A2 corrected according to the accelerator opening change amount _AD. The fuel injection amount Q _F is set based on the in-cylinder supply air amount Q and the engine speed Ne, and the driver 41 controls the air assist injector 24 to inject the set fuel injection amount Q _F. In step S18, the driver 41 controls the air assist injector 24 at the same time, and the corrected assist air amount Q _A2 is injected. As a result, the increased amount of fuel from the air assist injector 24 is injected into the intake port 18, and at the same time, the increased amount of assist air is injected into the injected fuel and atomized, and the fuel-air mixture is combusted. It is introduced into the chamber 17.

The phenomenon when this acceleration request is made will be described in detail. As shown in FIG. 3, when the driver depresses the accelerator pedal at time t ₁ and the throttle opening θ _T becomes large, the throttle valve 34 from the intake pipe 22 is increased. The intake air amount Q _A1 supplied to the combustion chamber 17 through the passage increases. At this time, since the intake air supplied from the intake pipe 22 to the combustion chamber 17 has a time delay, the intake air amount Q _A1 gradually increases without increasing rapidly as the throttle opening Q _T increases. To do. Therefore, conventionally, as shown by the dotted line in FIG. 3, the in-cylinder supplied air amount Q obtained by adding a small amount of assist air amount Q _A2 to the gradually increasing intake air amount Q _A1 gradually increases. Since the injection amount Q _F is set based on the in-cylinder supply air amount Q and the engine speed Ne, the generated torque T of the engine 11 increases with a delay with respect to the driver's acceleration request, and at time t ₂ . As the driver demands.

On the other hand, in the present embodiment, as indicated by a solid line in FIG. 3, when the driver depresses the accelerator pedal at time t ₁ and the throttle opening Q _T increases, the combustion chamber 17 passes through the throttle valve 34 from the intake pipe 22. The intake air amount Q _A1 supplied to the engine gradually increases, and the assist air amount Q _A2 increases based on the accelerator opening change amount _AD . Accordingly, the in-cylinder supply air amount Q set by adding the intake air amount Q _A1 and the assist air amount Q _A2 increases in synchronization with the throttle opening Q _T , and the fuel injection amount Q _F is also this Since the cylinder supply air amount Q increases in synchronization with the throttle opening Q _T , the generated torque T of the engine 11 increases instantaneously as required in response to the driver's acceleration request. The assist air amount Q _A2 increases when the throttle opening Q _T changes, then gradually decreases, and reaches a predetermined value at time t ₂ .

  As described above, in the control apparatus for an internal combustion engine of the present embodiment, secondary air together with fuel is supplied to the combustion chamber 17 with respect to the intake pipe 22 having the throttle valve 34 for supplying primary air to the combustion chamber 17. An air assist injector 24 is provided to correct the amount of secondary air supplied by the air assist injector 24 when there is a delay in supplying primary air to the combustion chamber 17 through the intake pipe 22 such as when the engine 11 is accelerated. Like to do.

  Therefore, when the engine 11 is accelerated by the driver's accelerator operation, when a temporary shortage of air in the combustion chamber 17 occurs due to a delay in the supply of primary air that is supplied to the combustion chamber 17 through the intake pipe 22, The amount of secondary air supplied by the air assist injector 24 is increased, and the intake air amount and the fuel injection amount necessary for accelerating the engine 11 can be secured, resulting from the delay in the supply of intake air to the combustion chamber 17. Response can be prevented and drivability can be improved.

In addition, the temporary shortage of the air amount to the combustion chamber 17 is assumed when the change amount _AD of the accelerator opening θ _A becomes equal to or larger than the set value A _S , thereby appropriately determining the driver's acceleration request. The engine output can be increased according to the driver's acceleration request. Further, the fuel injection amount Q _F is set based on the in-cylinder supply air amount Q (Q _A1 + Q _A2 ), and an appropriate fuel amount can be secured even when the assist air amount Q _A2 is increased.

  In addition, fuel and secondary air can be injected simultaneously by the air assist injector 24, so that the apparatus can be simplified and the manufacturing cost can be reduced.

In the above-described embodiment, the driver's acceleration request is presumed that the supply amount of the primary air to the combustion chamber 17 is insufficient when the accelerator opening θ _A becomes large. Although so as to increase the supply amount of the following air, when the driver had deceleration request that braking quit depression of the accelerator pedal, which on the basis of the change amount a _D accelerator opening theta _a The amount of primary air supplied to the combustion chamber 17 may be estimated to be excessive, and the amount of secondary air supplied from the air assist injector 24 may be reduced.

Although was determined based on the acceleration requested by the driver change amount A _D accelerator opening theta _A, may be a rate of change of the accelerator opening theta _A, other engine load such variation and change rate of the throttle valve 34 The determination may be made based on the change in. Further, although the air assist injector 24 is used as the fuel injection means and the secondary air supply means, the fuel injection means can be a general injector, and air can be directly supplied to the combustion chamber 17 and the intake port 18 as the secondary air supply means. An apparatus may be provided.

  The control device for an internal combustion engine according to the present invention enables primary air to be supplied to the combustion chamber through the intake passage, and allows secondary air to be supplied to the combustion chamber by means other than that, and delays in supply of primary air. By increasing or decreasing the amount of secondary air supplied when this occurs, the acceleration / deceleration response is prevented from deteriorating. The apparatus of the present invention can be applied even to an engine that injects into a chamber.

It is a block block diagram of the control apparatus of the internal combustion engine which concerns on one Example of this invention. It is a flowchart of control by the control apparatus of the internal combustion engine of a present Example. It is a time chart of control by the control device of the internal combustion engine of the present embodiment.

Explanation of symbols

11 Engine (Internal combustion engine)
17 Combustion chamber 22 Intake pipe 24 Air assist injector (fuel injection means, secondary air supply means)
25 Spark plug 28 Fuel tank 31 Compressor 34 Throttle valve (primary air supply means)
35 Throttle position sensor 36 Air flow sensor 38 Crank angle sensor 39 Electronic control unit, ECU (control means)
40 Accelerator position sensor

Claims (4)

  Primary air supply means for supplying primary air to the combustion chamber through the intake passage, fuel injection means for injecting fuel into the intake passage or the combustion chamber, and secondary air to the intake passage in the combustion chamber or in the vicinity of the combustion chamber Secondary air supply means, and control means for correcting the amount of secondary air supplied by the secondary air supply means when a delay occurs in the supply of primary air to the combustion chamber by the primary air supply means A control apparatus for an internal combustion engine characterized by comprising:   2. The control apparatus for an internal combustion engine according to claim 1, further comprising an accelerator opening degree detecting means for detecting an accelerator opening degree, wherein the control means performs the second operation when the amount of change in the accelerator opening is equal to or larger than a preset value. A control device for an internal combustion engine, wherein the supply amount of secondary air by the secondary air supply means is corrected.   2. The control device for an internal combustion engine according to claim 1, wherein said control means is based on said fuel injection means based on an intake air amount obtained by combining said primary air supply amount and said secondary air supply amount and an engine rotational speed. An internal combustion engine control apparatus for controlling a fuel injection amount. 2. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel injection means and the secondary air supply means are air assist injectors that inject fuel together with compressed air.

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