JP2010065569A - Fuel injection control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection control device of an internal combustion engine capable of further suitably restraining the occurrence of a misfire of the internal combustion engine after a complete explosion of the engine, by reflecting a difference in the cylinder temperature on fuel injection control. <P>SOLUTION: An electronic control device calculates time until a value of a timer correction quantity Q3 becomes 0 after the complete explosion of the engine by processing of a Step S12 when timer time T counted by a timer is shorter than a threshold value T0 by processing of a Step S11. A period for increasingly correcting a fuel injection quantity after the complete explosion is extended based on the time until the value of the timer correction quantity Q3 becomes 0 after the complete explosion of the engine. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection control device for an internal combustion engine in which the fuel injection amount is corrected to increase until a predetermined period has elapsed after the complete explosion of the engine.

  As fuel injection control for an internal combustion engine, control at start-up from the start of cranking to complete explosion of the engine and control after start-up from the end of the engine until the end of a predetermined period of time are performed differently from those during normal idling operation. It is known.

  For example, when the bore wall temperature of the internal combustion engine is extremely low, such as during cold start, the bore wall temperature rises even when the engine speed reaches a complete explosion exceeding the predetermined speed. If it is not sufficient, the in-cylinder temperature is also affected, it is difficult to promote the combustion of fuel, misfire may occur, and the exhaust gas quality resulting from incomplete combustion of the air-fuel mixture may deteriorate.

For this reason, in the past, as a control after starting, it has been known that the fuel injection amount is corrected to be increased from the time of normal idling until a certain period of time has passed since the complete explosion of the engine. 1 proposes that the engine coolant temperature at the time of starting the engine is detected, and that a predetermined period for performing the increase correction is corrected based on the detected engine coolant temperature. That is, the lower the engine coolant temperature is, the longer the period for increasing the fuel injection amount is to improve the misfire resistance.
Japanese Unexamined Patent Publication No. 7-34926

  In this way, the fuel increase correction is performed until the predetermined period elapses after the complete explosion of the engine, and the engine cooling water temperature is reflected in the predetermined period during which the increase correction is performed, thereby stabilizing the combustion state and generating misfires. Etc. can be suppressed to some extent. However, since the engine coolant temperature changes according to the combustion heat in the cylinder, it certainly changes in correlation with the cylinder temperature, but changes quickly according to the cylinder temperature at that time. It does not have the following capability. Therefore, it is difficult to estimate the in-cylinder temperature from the engine cooling water temperature during a transition after cranking of the internal combustion engine. In this regard, in Patent Document 1, the fuel increase period after the complete explosion of the engine is determined based on the engine coolant temperature at the start of cranking. If the in-cylinder temperature after the complete explosion and after the complete explosion is uniformly determined by the engine cooling water temperature at the start of cranking, there is no problem in the control of Patent Document 1, but there may be actual differences. Conventionally, there was no means for reflecting this difference in the fuel injection amount.

  An object of the present invention is to provide a fuel injection control device for an internal combustion engine that reflects the difference in the in-cylinder temperature in the fuel injection control and can more appropriately suppress the occurrence of misfire of the internal combustion engine after the complete explosion of the engine. There is to do.

  In order to achieve the above object, an invention according to claim 1 is a fuel injection control device for an internal combustion engine provided with an increase correction means for increasing the fuel injection amount until a predetermined period elapses after the complete explosion of the engine. The time counting means for measuring the period from the start of cranking to the completion of the engine complete explosion, and when the time measured by the time measuring means is shorter than the period estimated from the engine temperature, the fuel injection amount is corrected to be increased. And an adjusting means for adjusting the predetermined period.

  The present invention focuses on the bore wall surface temperature at the time of complete explosion of the internal combustion engine and the period from the start of cranking to the complete explosion of the engine. When cranking of the internal combustion engine is started by the engine starting operation, the air in the cylinder is compressed, so that the bore wall surface temperature is increased by the compression. Therefore, when the period from the start of cranking to the complete explosion of the engine is long, that is, when the air in the cylinder is repeatedly compressed by the piston for a long period of time, the bore wall surface temperature at the time of complete explosion becomes high. If it is short, the bore wall temperature remains low. Thus, it can be said that the period from the start of cranking to the complete explosion of the engine and the temperature in the cylinder at the complete explosion have a high correlation. On the other hand, the period from the start of cranking to the complete explosion of the engine is affected not only by temperature but also by friction, and particularly by the viscosity of lubricating oil. In general, the viscosity of the lubricating oil at a low temperature is high, and the friction of the entire internal combustion engine at the time of cranking also increases. However, if the viscosity of the lubricating oil becomes low even at low temperatures due to, for example, deterioration over time, the rotational speed of the internal combustion engine tends to increase, and the engine explosion can be easily reached. That is, when the engine complete explosion is reached in a short time compared to the engine temperature, it can be determined that the bore wall surface temperature is not sufficiently increased due to the low viscosity of the lubricating oil.

  In the present invention, when the period from the start of cranking to the complete explosion of the engine is short, that is, when it can be estimated that the rise in the bore wall temperature at the time of the complete explosion is low, the period for correcting the increase in the fuel injection amount is lengthened. Yes. Therefore, even if the actual in-cylinder temperature in the transient state cannot be estimated from the engine coolant temperature, the fuel injection amount increase correction period is adjusted by the adjusting means, so the fuel increase correction in accordance with the actual in-cylinder temperature is performed. It can be carried out. Therefore, the occurrence of misfire of the internal combustion engine after the complete explosion of the engine can be suppressed.

  According to a second aspect of the present invention, in the first aspect of the present invention, the adjusting means increases the fuel injection amount as the period from the start of cranking to the completion of the complete engine explosion is shorter. The gist is to extend the period.

  It can be estimated that the shorter the period from the start of cranking to the completion of the engine complete explosion, the lower the rise in the bore wall temperature at the time of the engine complete explosion, and the actual in-cylinder temperature in the transient state is considered to be extremely low. . Therefore, by increasing the predetermined period for correcting the fuel injection amount to be increased in such a state, it is possible to perform the fuel increase correction in accordance with the actual in-cylinder temperature. The occurrence of misfire can be suppressed.

  The invention according to claim 3 is the invention according to claim 1 or claim 2, wherein the adjusting means stops the increase correction of the fuel injection amount when the engine temperature is higher than a predetermined temperature. And

  According to the present invention, for example, when the in-cylinder temperature is high, such as when restarting at a high temperature, by stopping the fuel injection amount increase correction itself, an excessive fuel injection amount increase correction is performed. This can be prevented.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, when the period timed by the time measuring means is short, in addition to the adjustment of the predetermined period, the increase amount The gist of the correction means is to further increase the increase in the fuel injection amount.

  According to the present invention, for example, even if the actual in-cylinder temperature in the transient state is significantly lower than the in-cylinder temperature assumed from the engine cooling water temperature, in addition to the adjustment of the predetermined period, By further increasing the amount of increase, it is possible to perform fuel increase correction in accordance with the actual in-cylinder temperature. Therefore, the occurrence of misfire of the internal combustion engine after the complete explosion of the engine can be more suitably suppressed.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, in addition to the adjustment of the predetermined period, when the period counted by the timing unit is short, The gist of the invention is that it further includes an injection timing correcting means for correcting the injection timing to the advance side.

  According to the present invention, in addition to the adjustment of the predetermined period, by correcting the fuel injection timing to the advance side, it is possible to ensure a long time during which the injected fuel can self-ignite, so that the ignition can be reliably performed. Can be. Therefore, it further contributes to suppressing the occurrence of misfire of the internal combustion engine after the complete explosion of the engine.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, in addition to the adjustment of the predetermined period, the fuel injection is performed when the period counted by the timing unit is short. The gist is to further include an injection pressure adjusting means for adjusting the pressure so as to decrease.

  According to the present invention, in addition to the adjustment of the predetermined period, the fuel injection pressure is lowered to suppress the diffusion, the fuel injected into the cylinder is locally unevenly distributed, and the combustion chamber is partially rich. A spray can be formed. And since such a partially rich spray tends to self-ignite, the combustion region expands from the self-ignited spray to the surroundings. As a result, it is possible to further contribute to suppressing the occurrence of misfire of the internal combustion engine after the complete explosion of the engine.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the increase correction means executes pilot injection prior to the main injection, and the adjustment means The gist is to adjust at least a predetermined period during which the fuel injection amount of the pilot injection is increased.

  According to the present invention, when performing the pilot injection, the main injection is performed after the pilot-injected fuel is once burned by adjusting the predetermined period for correcting the increase in the fuel injection amount. The fuel injected in the main injection can be reliably ignited. Therefore, it is possible to further suppress the occurrence of misfire of the internal combustion engine after the complete explosion of the engine.

  According to the present invention, the difference in the in-cylinder temperature is reflected in the fuel injection control, and the occurrence of misfire of the internal combustion engine after the complete explosion of the engine can be more suitably suppressed.

  Hereinafter, an embodiment in which the present invention is embodied in a fuel injection device for a diesel engine will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a diesel engine (hereinafter simply referred to as “engine”) 11 to which a fuel injection control device according to the present embodiment is applied.

  As shown in FIG. 1, pistons 13 are accommodated in a plurality of cylinders 12 (only one is shown in FIG. 1) formed in the engine 11 so as to be able to reciprocate. The piston 13 is connected to the crankshaft 15 of the engine 11 via a connecting rod 14, and the connecting rod 14 converts the reciprocating motion of the piston 13 into the rotational motion of the crankshaft 15. At the start of cranking, the crankshaft 15 is rotationally driven (cranked) by the starter 18 until the engine 11 reaches a complete explosion state.

  In each cylinder 12, a combustion chamber 16 to which an intake passage 20 and an exhaust passage 21 are connected is defined above the piston 13. An injector 17 is attached to each combustion chamber 16 of each cylinder 12. A predetermined high pressure fuel is supplied to the injector 17 through a known fuel supply mechanism. The fuel is directly injected into the combustion chamber 16 by the valve opening drive of the injector 17.

  The engine 11 is controlled by the electronic control unit 30. The electronic control unit 30 includes a central processing unit (CPU) that executes various processes related to the control, and a memory that stores a control program and information necessary for control. Further, the electronic control unit 30 is the time from when the starter 18 is turned on through the operation of the key switch of the engine 11 until the engine speed exceeds the predetermined speed, that is, the time from the start of cranking to the completion of the complete explosion of the engine. In addition to the timer 39 functioning as a time measuring means for measuring (time keeping time T), a drive circuit for the injector 17 and the like are provided.

  In addition to the starter 18, the electronic control unit 30 is connected to various sensors that detect the engine operating state. For example, the crank sensor 31 detects the phase angle of the crankshaft 15, that is, the crank angle, and calculates the engine speed based on this. In addition, the electronic control unit 30 includes a pressure sensor 32 that detects the pressure (atmospheric pressure) in the intake passage 20, a water temperature sensor 33 that detects the temperature of the engine cooling water (engine cooling water temperature), and the temperature of the intake air (intake air temperature). Various sensors such as a temperature sensor 34 for detecting the above are connected. Then, the electronic control unit 30 executes various controls including fuel injection control in accordance with the operation status of the engine 11 grasped by the detection signals of these various sensors.

  Next, normal fuel injection control of the engine 11 will be described with reference to FIG. At the start of cranking, the starter 18 is turned on to forcibly rotate the crankshaft 15, and fuel is injected from the injector 17 into the combustion chamber 16 based on an injection signal from the electronic control unit 30. . Thus, when the crankshaft 15 is forcibly driven to rotate and the fuel injection is executed, the engine speed is gradually increased to reach a predetermined speed (around 800 rpm), and the engine 11 is regarded as a complete explosion state. .

  Thus, when the engine 11 reaches the complete explosion state, the electronic control unit 30 performs the fuel injection control (startup control) from the cranking start to the engine complete explosion until the predetermined period elapses after the engine complete explosion. Shift to control (post-startup control). Specifically, the basic injection amount Q1 calculated based on the operating state of the engine, the temperature correction amount Q2 calculated based on the engine temperature (engine cooling water temperature in the present embodiment), and the time measuring means. A time correction amount Q3 calculated based on the time T and the engine temperature (in this embodiment, the engine coolant temperature) is calculated. The injector 17 injects an amount of fuel corresponding to the sum (= Q1 + Q2 + Q3) of the injection amount Q1 and the correction amounts Q2 and Q3 into the combustion chamber 16 based on the injection signal from the electronic control unit 30. The basic injection amount Q1 is set based on the engine speed and the load (accelerator opening degree and driving state of the accessories), while the temperature correction amount Q2 is gradually increased as time elapses from the complete explosion. To decrease. Further, when the time correction amount Q3 takes a positive value other than 0, the time correction amount Q3 is set to be 0 later than at the time when the value of the temperature correction amount Q2 becomes 0 at least. As described above, the electronic control unit 30 functions as an increase correction unit that increases the fuel with the temperature correction amount Q2 and the timing correction amount Q3 after the engine 11 has shifted to the complete explosion state.

  Next, fuel injection control executed by the electronic control unit 30 will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing the processing procedure of the fuel injection control, and FIG. 4 is a timing chart showing the transition of the fuel injection amount during the execution of the fuel injection control.

  As shown in FIG. 3, first, the electronic control unit 30 detects and stores the engine cooling water temperature at the start of cranking, and calculates the time T measured by the timer 39 (step S10). Next, the electronic control unit 30 determines whether or not the time count T calculated in step S10 is shorter than the threshold value T0 (step S11). Here, the threshold value T0 is the time from the start of cranking to the complete explosion when the engine is started under the standard in-cylinder temperature of each cylinder 12 estimated from the engine coolant temperature at the start of cranking. This is the time that is normally considered to be required. The relationship between the engine coolant temperature at the start of cranking and the threshold value T0 is considered to be such that the higher the engine coolant temperature at the start of cranking, the higher the in-cylinder temperature. If attention is paid only to the engine temperature, it is estimated that the higher the in-cylinder temperature, the shorter the time normally required from the start of cranking to the complete explosion. Therefore, as shown in FIG. 6, the threshold T0 is set smaller as the engine coolant temperature is higher. On the other hand, the lower the engine coolant temperature at the start of cranking, the lower the in-cylinder temperature. And it is estimated that the time normally required from the cranking start time to the complete explosion becomes longer as the in-cylinder temperature is lower. Therefore, as shown in FIG. 6, the lower the engine coolant temperature, the larger the threshold T0 is set.

  If the determination result in step S11 is affirmative, it is estimated that the viscosity of the lubricating oil is lower than that in the standard state. Therefore, the actual in-cylinder temperature is lower than the in-cylinder temperature estimated from the engine cooling water temperature. It is estimated to be. In this case, the electronic control unit 30 calculates the time until the value of the time correction amount Q3 becomes 0 after the complete explosion of the engine (step S12). As shown in FIG. 5, the time required for the time correction amount Q3 to reach zero after the engine complete explosion is short as the time T required from the start of cranking to the complete explosion, and the cranking starts. The lower the engine coolant temperature at the time, the higher the positive value is set over a long period of time. On the other hand, the time correction amount Q3 is set to 0 in a shorter time as the time T required from the start of cranking to the complete explosion is longer, and as the engine coolant temperature at the start of cranking is higher.

  For example, when the time T from the start of cranking to the complete explosion is short, the time T1 until the value of the time correction amount Q3 becomes 0 after the engine complete explosion takes a positive value over a long period of time. Is set as follows. Therefore, the electronic control unit 30 corrects the increase in the fuel injection amount after the complete explosion so that the time correction amount Q3 becomes 0 when the time T1 has elapsed after the complete explosion as shown by the solid line in FIG. The increase correction period is extended so as to change with the transition. When the time T1 has elapsed after the complete explosion of the engine, the value of the temperature correction amount Q2 has already become 0 as shown by the two-dot chain line in FIG. On the other hand, if the time T from the start of cranking to the complete explosion is long, the time T2 (<T1) until the value of the time correction amount Q3 becomes 0 after the engine complete explosion is the value of the time correction amount Q3. Is set to 0 in a short time. Therefore, the electronic control unit 30 corrects the increase in the fuel injection amount after the complete explosion so that the time correction amount Q3 becomes zero when the time T2 has elapsed after the complete explosion as shown by the alternate long and short dash line in FIG. The period of increasing correction is extended so as to change with a long transition. When the time T2 has elapsed after the complete explosion of the engine, the value of the temperature correction amount Q2 has already become 0 as shown by the two-dot chain line in FIG. As described above, the electronic control unit 30 is an adjustment unit that adjusts the period for increasing the fuel injection amount after the complete explosion based on the time until the value of the time correction amount Q3 becomes 0 after the engine complete explosion. Function.

  Then, the electronic control unit 30 extends the period for increasing the fuel injection amount after the complete explosion for the time until the value of the time correction amount Q3 calculated in step S12 becomes 0 after the engine complete explosion. Thus, a signal to inject fuel is transmitted to the injector 17 (step S13). The injector 17 injects fuel for the fuel injection amount after the complete explosion into the combustion chamber 16 based on this injection signal.

  On the other hand, when the determination result of step S11 is negative, the threshold T0 is set to be extremely small, in other words, the engine coolant temperature at the start of cranking is extremely high. It is assumed that the in-cylinder temperature is high. Therefore, the electronic control unit 30 stops the increase correction of the fuel injection amount after the complete explosion.

  When the piston 13 of the engine 11 reciprocates by the engine start operation, the air in the cylinder 12 is compressed, so that the temperature in the cylinder 12 rises due to the compression. Therefore, when the period from the start of cranking to the complete explosion is long, that is, when the air in the cylinder 12 is compressed over a long period of time by the piston 13, the temperature in the cylinder 12 becomes high, and conversely, The temperature in the cylinder 12 becomes low. Thus, it can be said that the period from the start of cranking to the complete explosion and the temperature in the cylinder 12 after the complete explosion have a high correlation. Therefore, when the time T measured by the timer 39 is shorter than the threshold value T0, the in-cylinder temperature after the actual complete explosion may be much lower than the in-cylinder temperature assumed from the engine coolant temperature. In this case, even if the fuel increase correction based on the engine coolant temperature is performed as in the normal fuel injection control of the engine 11, the fuel increase correction in accordance with the actual in-cylinder temperature cannot be performed. Misfires and incomplete combustion resulting from this are inevitable. However, the fuel increase correction corresponding to the actual in-cylinder temperature can be performed by extending the period for increasing the fuel injection amount after the complete explosion as the time T measured by the timer 39 is shorter. .

In the embodiment described above, the following effects can be obtained.
(1) When the time T measured by the timer 39 is shorter than the threshold T0, the electronic control unit 30 completes based on the time until the value of the time correction amount Q3 becomes 0 after the engine complete explosion. Extend the period to compensate for increased fuel injection after the explosion. Therefore, even if the actual in-cylinder temperature after the complete explosion is much lower than the in-cylinder temperature that is assumed from the engine coolant temperature, the period for increasing the fuel injection amount after the complete explosion should be extended. Thus, it is possible to perform the fuel increase correction in accordance with the actual in-cylinder temperature. As a result, it is possible to more suitably suppress the occurrence of misfire of the engine 11 after the complete explosion of the engine.

  (2) When the time T measured by the timer 39 is longer than the threshold T0, the threshold T0 is set to be extremely small, in other words, the engine coolant temperature at the start of cranking is extremely high. For example, it is assumed that the in-cylinder temperature is high as in a high temperature restart. In such a case where the temperature in the cylinder 12 is high such as at the time of high temperature restart, the electronic control unit 30 stops the increase correction of the fuel injection amount after the complete explosion. Therefore, when the in-cylinder temperature is high, such as when restarting at a high temperature, in other words, when the in-cylinder temperature is high in the first place, the increase correction of the excessive fuel injection amount is performed by stopping the increase correction itself. It can be prevented from being broken.

In addition, this embodiment can also be implemented with the following aspects which changed this suitably.
○ When the engine is started under the standard in-cylinder temperature of each cylinder 12 estimated from the intake temperature at the start of cranking detected from the temperature sensor 34, the threshold value T0 is from the start of cranking. It may be the time normally considered to be complete. Regarding the relationship between the intake air temperature at the start of cranking and the threshold value T0, it is considered that the in-cylinder temperature is higher as the intake air temperature at the start of cranking is higher. It is estimated that the higher the in-cylinder temperature, the shorter the time normally required from the start of cranking to the complete explosion. Therefore, as shown in FIG. 7, the threshold T0 is set smaller as the in-cylinder temperature is higher. On the other hand, the lower the intake air temperature at the start of cranking, the lower the in-cylinder temperature. And it is estimated that the time normally required from the cranking start time to the complete explosion becomes longer as the in-cylinder temperature is lower. Therefore, as shown in FIG. 7, the lower the in-cylinder temperature, the larger the threshold T0 is set.

  ○ When the engine is started under the standard in-cylinder temperature of each cylinder 12 estimated from the atmospheric pressure at the start of cranking detected from the pressure sensor 32, the threshold T0 is from the start of cranking. It may be the time normally considered to be complete. The relationship between the atmospheric pressure at the start of cranking and the threshold value T0 is considered to be such that the higher the atmospheric pressure at the start of cranking, the higher the in-cylinder temperature. It is estimated that the higher the in-cylinder temperature, the shorter the time normally required from the start of cranking to the complete explosion. Therefore, as shown in FIG. 8, the threshold T0 is set smaller as the in-cylinder temperature is higher. On the other hand, it is considered that the in-cylinder temperature is lower as the atmospheric pressure at the start of cranking is lower. And it is estimated that the time normally required from the cranking start time to the complete explosion becomes longer as the in-cylinder temperature is lower. Therefore, as shown in FIG. 8, the threshold T0 is set larger as the in-cylinder temperature is lower.

  The electronic control unit 30 may add a function of further increasing the fuel injection amount increase after the complete explosion when the time T measured by the timer 39 is shorter than the threshold T0. According to this, for example, even if the actual in-cylinder temperature in the transient state is much lower than the in-cylinder temperature assumed from the engine cooling water temperature, the fuel injection amount can be further increased. Further, it is possible to perform the fuel increase correction in accordance with the actual in-cylinder temperature. Therefore, the occurrence of misfire of the internal combustion engine after the complete explosion of the engine can be more suitably suppressed.

  The electronic control unit 30 may add a function as an injection timing correction unit that corrects the fuel injection timing to the advance side when the time T measured by the timer 39 is shorter than the threshold T0. . According to this, by correcting the fuel injection timing to the advance side, it is possible to ensure a long time during which the injected fuel can self-ignite, so that the ignition can be ensured. Therefore, it further contributes to suppressing the occurrence of misfire of the engine 11 after the complete explosion of the engine.

  The electronic control unit 30 may adjust the fuel injection pressure so that the fuel injection pressure decreases when the time T measured by the timer 39 is shorter than the threshold value T0, that is, add a function as an injection pressure adjusting means. Good. According to this, by reducing the fuel injection pressure, the fuel injected into the combustion chamber 16 can be locally unevenly distributed, and a partially rich spray can be formed in the combustion chamber 16. And since such a partially rich spray tends to self-ignite, the combustion region expands from the self-ignited spray to the surroundings. As a result, it is possible to further contribute to suppressing the misfire of the engine 11 after the complete explosion of the engine.

  The electronic control unit 30 sends a signal to the injector 17 to inject fuel into the combustion chamber 16 so as to execute pilot injection prior to main injection, and the time measured by the timer 39 When the time T is short, at least the period during which the fuel injection amount of the pilot injection is corrected to increase may be adjusted. According to this, when the pilot injection is executed, the main injection is executed after the pilot-injected fuel is burned once by extending the period for correcting the increase in the fuel injection amount. The fuel injected in the main injection can be reliably ignited. Accordingly, it is possible to further suppress the occurrence of misfire of the engine 11 after the engine is started.

The electronic control unit 30 may add a function of decreasing the fuel injection amount increase correction degree as the engine temperature is higher, such as the engine coolant temperature.
The electronic control unit 30 may be configured to function as both the injection timing correction unit and the injection pressure adjustment unit. Further, in addition to this configuration, when the time T counted by the timer 39 is short, at least the period for increasing the fuel injection amount of the pilot injection may be adjusted.

  The present invention can be applied not only to a diesel engine but also to a gasoline engine.

Schematic which shows the whole structure of the engine fuel-injection control apparatus in this embodiment. The time chart which shows the fuel-injection control procedure of a normal engine. The flowchart which shows the fuel-injection control procedure in this embodiment. The time chart which shows the fuel-injection control procedure in this embodiment. The graph which shows the relationship between the time until the value of the time correction amount becomes 0 after the engine complete explosion, the time from the cranking start to the complete explosion (time measurement time), and the engine coolant temperature. The graph which shows the relationship between the threshold value in this embodiment, and the engine cooling water temperature at the time of cranking start. The graph which shows the relationship between the threshold value in another embodiment, and the intake temperature at the time of cranking start. The graph which shows the relationship between the threshold value in another embodiment, and the atmospheric pressure at the time of cranking start.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Engine, 30 ... Electronic control unit, 39 ... Timer as time measuring means.

Claims (7)

A fuel injection control device for an internal combustion engine comprising an increase correction means for increasing the fuel injection amount until a predetermined period has elapsed after the engine complete explosion,
A time measuring means for measuring the period from the start of cranking to the completion of the complete explosion,
Adjusting means for adjusting a predetermined period for increasing the fuel injection amount when a period timed by the time measuring means is shorter than a period estimated from the engine temperature. Injection control device. The fuel injection control device for an internal combustion engine according to claim 1,
The fuel injection control device for an internal combustion engine, wherein the adjustment means extends the predetermined period for increasing the fuel injection amount as the period from the start of cranking to the completion of the complete engine explosion is shorter. The fuel injection control device for an internal combustion engine according to claim 1 or 2,
The fuel injection control device for an internal combustion engine, wherein the adjustment means stops the increase correction of the fuel injection amount when the engine temperature is higher than a predetermined temperature. 4. When the period counted by the timing unit is short, in addition to the adjustment of the predetermined period, the increase correction unit further increases the increase of the fuel injection amount. 5. A fuel injection control device for an internal combustion engine as described. The fuel injection timing correction means for correcting the fuel injection timing to the advance side in addition to the adjustment of the predetermined period when the time counted by the time measuring means is short. A fuel injection control device for an internal combustion engine according to the item. The injection pressure adjusting means for adjusting the fuel injection pressure so as to decrease in addition to the adjustment of the predetermined period when the time measured by the time measuring means is short. The fuel injection control device for an internal combustion engine according to one item. The fuel injection control device for an internal combustion engine according to any one of claims 1 to 6,
The increase correction means executes pilot injection prior to main injection,
The fuel injection control device for an internal combustion engine, wherein the adjusting means adjusts at least a predetermined period during which the fuel injection amount of the pilot injection is increased.

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