JP4516140B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that controls fuel injection at the time of cold start of the internal combustion engine.

  When starting the internal combustion engine at a low temperature (during cold start), since both the fuel temperature and the ambient temperature are low, it is difficult for the fuel to volatilize and it is difficult to ensure good startability. At this time, in order to obtain the air-fuel ratio necessary for starting the internal combustion engine, it is necessary to increase the fuel injection amount from the normal time, and the exhaust gas deteriorates.

  In recent years, alcohol has attracted attention as an alternative fuel to conventional gasoline due to air pollution and fluctuations in petroleum conditions. Further, for example, a flex fuel vehicle (FFV) that travels using a mixed fuel of gasoline and ethanol (ethanol 0% to ethanol 100%) has been put into practical use.

  Here, it is generally known that the volatility of alcohol at a low temperature is lower than that of gasoline. Therefore, regarding the start of the internal combustion engine at a low temperature, when a fuel having a high alcohol concentration such as 100% ethanol is used, it becomes more difficult to ensure good startability and the exhaust gas is further deteriorated. There is a problem.

Then, as what solves said problem, the following are mentioned, for example.
A conventional fuel heating control device for an internal combustion engine includes a delivery pipe heater provided in a delivery pipe that distributes fuel to the injectors of each cylinder, a cooling water temperature sensor that detects the temperature of cooling water in the internal combustion engine, and a control unit. It has.
The control means heats the fuel using a delivery pipe heater according to the temperature of the cooling water of the internal combustion engine (see, for example, Patent Document 1).

  As described above, the conventional fuel heating control apparatus heats the fuel using the delivery pipe heater and increases the volatility of the fuel, thereby ensuring good startability even when the internal combustion engine is cold. At the same time, it prevents the exhaust gas from deteriorating.

On the other hand, as fuel injection control at the time of starting the internal combustion engine, all-cylinder simultaneous injection control in which a large amount of fuel is simultaneously injected into all the cylinders is known only at the time of initial injection at the time of starting.
In all-cylinder simultaneous injection control, by injecting a large amount of fuel, a liquid film of fuel is formed on the inner wall surface of the intake port, promoting vaporization of the attached fuel and increasing the amount of fuel introduced into the cylinder. ing. In addition, by injecting fuel to all cylinders simultaneously, the time until the internal combustion engine starts up (starting time) is shortened.

JP 2005-2933 A

However, the prior art has the following problems.
FIG. 15 is an explanatory diagram showing a fuel injection state when all cylinder simultaneous injection control is executed in a conventional fuel heating control apparatus for an internal combustion engine. In FIG. 15, the delivery pipe heater is omitted.
When the fuel heated by the delivery pipe heater is injected into all the cylinders by the simultaneous injection control of all the cylinders at the time of the initial injection at the time of cold start of the internal combustion engine, it is a low temperature and the initial injection. A large amount of fuel injection is required as shown in FIG. That is, a large amount of heated fuel in the delivery pipe 13 is consumed by one fuel injection.

Here, when the heated fuel in the delivery pipe 13 is injected from the injector 12, unheated new fuel is supplied from the fuel pipe 15 into the delivery pipe 13 by the amount of the injected fuel. That is, before the first injection is completed (during the first injection), the unheated new fuel arrives in order from the injector 12 (first injector 12a) closest to the inlet of the delivery pipe 13. When unheated new fuel reaches the injector 12 during the initial injection, the fuel is used for the initial injection at a low temperature.
At this time, the fuel injected from the injector 12 near the inlet of the delivery pipe 13 is a mixture of heated fuel and unheated fuel, and the average temperature of the injected fuel is lower than the temperature of the heated fuel. On the other hand, all of the heated fuel is injected from the injector 12 far from the inlet of the delivery pipe 13.

Therefore, in the conventional fuel heating control device for an internal combustion engine, when all cylinders simultaneous injection control is executed, there is a possibility that unheated new fuel may reach the injector 12 during the first injection. In the cylinder close to the inlet, the fuel is less likely to volatilize than in the cylinder far from the inlet of the delivery pipe 13.
Further, since the fuel injection amount must be increased as the temperature becomes lower, the ratio of unheated fuel increases in the cylinder close to the inlet of the delivery pipe 13, and the average temperature of the injected fuel becomes lower as the temperature becomes lower.
For this reason, although the fuel is heated using the delivery pipe heater, there is a problem that good startability cannot be sufficiently secured and deterioration of exhaust gas cannot be prevented sufficiently.

  The present invention has been made to solve the above-described problems, and its purpose is to prevent unheated fuel from reaching the injector during the initial injection, and at the time of cold start of the internal combustion engine. Even if it exists, it is providing the control apparatus of the internal combustion engine which can ensure favorable startability and can prevent deterioration of exhaust gas.

  A control apparatus for an internal combustion engine according to the present invention includes a plurality of injectors that inject fuel into each of a plurality of cylinders of the internal combustion engine, a delivery pipe that distributes the fuel to the plurality of injectors, and a delivery that heats the fuel in the delivery pipe. A pipe heater, a fuel heating control means for controlling the operation of the delivery pipe heater, and a fuel injection control means for controlling the injection of fuel from the plurality of injectors, the fuel injection control means at the time of initial injection of the plurality of injectors When the fuel is heated by the fuel heating control means, the heated fuel is sequentially injected from the injector closest to the inlet of the delivery pipe.

According to the control device for an internal combustion engine of the present invention, the fuel injection control means sequentially starts from the injector closest to the inlet of the delivery pipe when the fuel is heated by the fuel heating control means during the initial injection of the plurality of injectors. Inject the heated fuel.
Therefore, it is possible to prevent unheated fuel from reaching the injector during the first injection, and to ensure good startability and prevent deterioration of exhaust gas even when the internal combustion engine is cold. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts will be described with the same reference numerals.
In the following embodiment, an in-line four-cylinder internal combustion engine will be described as an example. However, the present invention is not limited to this, and the number of cylinders in the internal combustion engine may be another number.

  The control device for an internal combustion engine of the present invention combines fuel injection control when the fuel is heated at the time of initial injection at the start of the internal combustion engine and fuel injection control according to the initial injection amount at the time of initial injection. As a result, the starting time until the internal combustion engine starts up can be shortened, and the exhaust gas can be prevented from deteriorating.

Embodiment 1 FIG.
1 is a configuration diagram showing an entire system including a control device for an internal combustion engine according to Embodiment 1 of the present invention. The internal combustion engine 1 (hereinafter referred to as “engine 1”) is provided with four cylinders 2. In FIG. 1, only one cylinder 2 is shown.

In FIG. 1, an engine 1 has a combustion chamber 4 in which a mixture of fuel and air is sucked and burned by a cylindrical cylinder 2 and a piston 3 connected to a crankshaft (not shown). Is formed.
Here, the piston 3 is provided so as to reciprocate in the axial direction of the cylinder 2. The crankshaft is provided with a crank angle sensor 5 that generates a signal in synchronization with the rotation of the engine 1. Further, the cylinder 2 is provided with a water temperature sensor 6 that outputs a voltage corresponding to the temperature of cooling water (not shown) for cooling the engine 1.

Connected to the cylinder 2 are an intake manifold 7 that sucks air into the cylinder 2 and an exhaust manifold 8 that discharges exhaust gas generated by combustion of the air-fuel mixture in the combustion chamber 4. Further, an intake valve 9 that opens and closes between the combustion chamber 4 and the intake manifold 7 and an exhaust valve 10 that opens and closes between the combustion chamber 4 and the exhaust manifold 8 are attached to the cylinder 2.
A spark plug 11 that ignites the air-fuel mixture supplied to the combustion chamber 4 is attached to the top of the cylinder 2.

An injector 12 for injecting fuel is attached in the vicinity of the intake valve 9 on the downstream side of the intake manifold 7. Thereby, fuel can be supplied into the cylinder 2 at an optimal timing.
In addition, a delivery pipe 13 that distributes fuel to the injectors 12 of the four cylinders 2 is connected to the injector 12. The delivery pipe 13 is provided with a delivery pipe heater 14 for heating the fuel in the delivery pipe 13.
Hereinafter, the configuration of the injector 12, the delivery pipe 13, and the delivery pipe heater 14 will be described in detail with reference to FIG.

FIG. 2 is a configuration diagram showing the injector 12, the delivery pipe 13, and the delivery pipe heater 14 in the control apparatus for an internal combustion engine according to the first embodiment of the present invention.
In FIG. 2, four injectors 12 corresponding to each of the four cylinders 2 are attached to the delivery pipe 13. The fuel is supplied to the delivery pipe 13 from the fuel pipe 15 connected to the delivery pipe 13, and is distributed from the delivery pipe 13 to each injector 12.

Here, the first injector 12a, the second injector 12b, the third injector 12c, and the fourth injector 12d are sequentially arranged from the injector 12 close to the inlet of the delivery pipe 13.
In addition, a delivery pipe heater 14 that heats fuel in the delivery pipe 13 is provided outside the delivery pipe 13 so as to cover the delivery pipe 13. The delivery pipe heater 14 may be provided inside the delivery pipe 13.

In FIG. 1, a surge tank 16 that temporarily stores air sucked into the combustion chamber 4 is connected to the upstream side of the intake manifold 7, and a throttle valve 17 is provided on the upstream side of the surge tank 16. ing. A boost pressure sensor 18 that outputs a voltage corresponding to the boost pressure is provided downstream of the throttle valve 17.
A catalyst device 19 that removes harmful substances in the exhaust gas is connected to the downstream side of the exhaust manifold 8, and a tail pipe 20 that discharges the exhaust gas to the outside is connected to the downstream side of the catalyst device 19. .

Here, the heating operation of the delivery pipe heater 14 and the fuel injection operation of the injector 12 are controlled by an engine control electronic control unit 30 (hereinafter abbreviated as “ECU 30”) that constitutes a main part of the control device of the internal combustion engine. Has been.
The ECU 30 includes fuel heating control means and fuel injection control means.

Here, the ECU 30 includes a CPU that performs arithmetic processing, a ROM that stores program data and fixed value data, a RAM that can be sequentially rewritten by updating stored data, and data that is stored even when the ECU 30 is turned off. It includes a backup RAM to be held, a drive circuit for driving the actuator, an A / D converter that converts analog signals of various sensors into digital signals, and an I / O interface that inputs and outputs various signals. These configurations are not shown.
Further, each block constituting the ECU 30 is stored as software in the ROM.

  In addition, the voltage output values from the water temperature sensor 6 and the boost pressure sensor 18 are A / D converted by the A / D converter and input to the ECU 30 via the I / O interface. Each A / D converted output value is used as the coolant temperature Tw and the boost pressure Pb for calculation in each means. Further, the ECU 30 receives an interrupt signal from the crank angle sensor 5 and calculates an engine speed Ne from a timer built in the ECU 30 and a signal from the crank angle sensor 5, and is used for the calculation in each of the above means. .

  The fuel heating control means compares the engine startable water temperature set according to the concentration of alcohol mixed with gasoline and the cooling water temperature Tw. Further, when the cooling water temperature Tw is lower than the water temperature at which the engine can be started at the current alcohol concentration, the fuel heating control means energizes the delivery pipe heater 14 during the energization time according to the alcohol concentration, and delivers the delivery pipe 13. Heat the fuel inside. On the other hand, the fuel heating control means does not energize the delivery pipe heater 14 when the coolant temperature Tw is equal to or higher than the engine startable water temperature.

Since the volatility of the fuel decreases as the alcohol concentration increases, the engine startable water temperature set according to the alcohol concentration is set such that the water temperature increases as the alcohol concentration increases. The energization time according to the alcohol concentration is set so that the time increases as the alcohol concentration increases.
Further, the fuel heating control means executes the fuel heating operation only after the engine 1 is started until the first injection by the injector 12 is performed.

The fuel injection control means calculates a fuel injection amount based on the boost pressure Pb and the engine speed Ne, and drives the injector 12 according to the fuel injection amount.
The fuel injection control means executes the following control only at the time of initial injection when the engine 1 is started.

FIG. 3 is a block diagram showing a detailed configuration of the fuel injection control means 34 in the control apparatus for an internal combustion engine according to the first embodiment of the present invention, together with the fuel heating control means 33.
In FIG. 3, the fuel injection control means 34 has an initial sequential injection control means 41.

The first sequential injection control means 41 injects fuel from the first injector 12a closest to the inlet of the delivery pipe 13 to the fourth injector 12d in order from the first injection of the injector 12 when the engine 1 is started.
The initial injection amount at the time of the initial injection is set in advance according to the cooling water temperature Tw, and is usually set so that the injection amount increases as the cooling water temperature Tw decreases. When the fuel contains alcohol, the initial injection amount is set according to the cooling water temperature Tw and the alcohol concentration.

Hereinafter, the fuel injection operation at the start of the engine 1 in the control apparatus for an internal combustion engine having the above-described configuration will be described.
First, an initial injection routine by the fuel heating control means 33 and the fuel injection control means 34 will be described with reference to the flowchart of FIG. This operation is executed as a subroutine while the main routine is executed in the ECU 30 at a predetermined time period.

First, the fuel injection control means 34 determines whether or not it is immediately after key-on (step S101).
In step S101, when it is determined that the key-on is immediately after (that is, Yes), the fuel injection control unit 34 stores 1 corresponding to the first injector 12a as the first injection cylinder Ic of the first sequential injection. (Step S102).

Further, since the initial injection has not been performed yet, the fuel injection control means 34 sets the initial injection execution flag Fs to 1 (step S103).
Steps S102 and S103 are parameter and flag initialization processing.
On the other hand, when it is determined in step S101 that it is not immediately after key-on (that is, No), the process proceeds to step S104.

Subsequently, the fuel heating control means 33 determines whether or not the fuel heating control condition is satisfied (step S104).
Here, it is determined that the fuel heating control condition is satisfied when the following two conditions are satisfied. First, the first condition is that the initial injection execution flag Fs is set to 1. The second condition is that the cooling water temperature Tw is lower than the engine startable water temperature set according to the alcohol concentration, or the current delivery pipe heater 14 is in the energized state and the energization time according to the alcohol concentration. It is a condition that it is within.

  If it is determined in step S104 that the fuel heating control condition is satisfied (that is, Yes), the fuel heating control means 33 energizes the delivery pipe heater 14 (step S105) and returns to the main routine. .

  On the other hand, if it is determined in step S104 that the fuel heating control condition is not satisfied (that is, No), the fuel heating control means 33 does not energize the delivery pipe heater 14 (step S106), that is, the delivery pipe. When the heater 14 is energized, the energization is stopped.

Next, the fuel injection control means 34 determines whether or not the initial injection execution flag Fs is set to 1 (step S107).
If it is determined in step S107 that the initial injection execution flag Fs is set to 1 (that is, Yes), the fuel injection control means 34 uses the initial sequential injection control means 41 to execute the initial sequential shown in FIG. The injection routine is executed (step S108), and the process returns to the main routine.
On the other hand, if it is determined in step S107 that the initial injection execution flag Fs is not set to 1 (ie, No), the process directly returns to the main routine.

  Next, an initial sequential injection routine by the initial sequential injection control means 41 will be described with reference to the flowchart of FIG. This operation is executed as a subroutine in step S108 of the flowchart of FIG.

First, the initial sequential injection control means 41 determines whether 1 is stored in the injection cylinder Ic (step S201). Here, in the case of the first injection in the initial sequential injection routine, since 1 is stored in the injection cylinder Ic, the condition is satisfied.
In step S201, when it is determined that 1 is stored in the injection cylinder Ic (that is, Yes), the initial sequential injection control means 41 performs the fuel injection of the first injector 12a closest to the inlet of the delivery pipe 13. Is performed (step S202).
The initial sequential injection control means 41 stores 2 corresponding to the second injector 12b as the injection cylinder Ic next to the initial sequential injection (step S203), and returns to the initial injection routine and the main routine.

On the other hand, if it is determined in step S201 that 1 is not stored in the injection cylinder Ic (ie, No), the initial sequential injection control means 41 determines whether 2 is stored in the injection cylinder Ic. Determination is made (step S204).
In step S204, when it is determined that 2 is stored in the injection cylinder Ic (that is, Yes), the initial sequential injection control means 41 performs fuel injection of the second injector 12b (step S205).
The initial sequential injection control means 41 stores 3 corresponding to the third injector 12c as the injection cylinder Ic next to the initial sequential injection (step S206), and returns to the initial injection routine and the main routine.

On the other hand, if it is determined in step S204 that 2 is not stored in the injection cylinder Ic (that is, No), the initial sequential injection control means 41 determines whether 3 is stored in the injection cylinder Ic. Determination is made (step S207).
If it is determined in step S207 that 3 is stored in the injection cylinder Ic (that is, Yes), the initial sequential injection control means 41 performs fuel injection of the third injector 12c (step S208).
Further, the initial sequential injection control means 41 stores 4 corresponding to the fourth injector 12d as the injection cylinder Ic next to the initial sequential injection (step S209), and returns to the initial injection routine and the main routine.

On the other hand, if it is determined in step S207 that 3 is not stored in the injection cylinder Ic (that is, No), the first sequential injection control means 41 is the fourth corresponding to 4 stored as the injection cylinder Ic. The fuel injection of the injector 12d is performed (step S210).
Further, the initial sequential injection control means 41 sets the initial injection execution flag Fs to 0 (step S211) because the initial sequential injection has been completed for all the cylinders 2, and returns to the initial injection routine and the main routine.

Here, the first sequential injection at the start of the engine 1 described so far will be described with reference to FIG.
FIG. 6 is an explanatory diagram showing the initial sequential injection of the control device for the internal combustion engine according to the first embodiment of the present invention. In FIG. 6, the delivery pipe heater is omitted.

  In FIG. 6, when performing the initial injection at the time of cold start of the engine 1, the fuel is heated by the delivery pipe heater 14, and immediately before the initial injection, the vicinity of the delivery pipe 13 and the injectors 12 a to 12 d is filled with the heated fuel. Yes. The fuel pipe 15 connected to the inlet of the delivery pipe 13 is filled with unheated fuel.

Here, when the heated fuel in the delivery pipe 13 is injected from the first injector 12a, the unheated new fuel is supplied into the delivery pipe 13 from the fuel pipe 15 by the amount of the injected fuel.
Subsequently, since the unheated new fuel supplied by the injection of the first injector 12a has not reached the vicinity of the second injector 12b at the time of fuel injection of the second injector 12b, from the second injector 12b, Only heated fuel is injected. At this time, unheated new fuel is supplied from the fuel pipe 15 into the delivery pipe 13 by the amount injected from the second injector 12b.

  Next, similarly, during the fuel injection of the third injector 12c and the fourth injector 12d, the unheated new fuel does not reach the vicinity of the third injector 12c and the fourth injector 12d. Therefore, only heated fuel is injected from the third injector 12c and the fourth injector 12d.

According to the control apparatus for an internal combustion engine according to the first embodiment of the present invention, the fuel injection control means 34, when the fuel is heated by the fuel heating control means 33 during the initial injection at the start of the engine 1, The first sequential injection control means 41 injects the fuel heated up to the fourth injector 12d in order from the first injector 12a closest to the inlet of the delivery pipe 13.
Therefore, it is possible to prevent unheated fuel from reaching the injector 12 during the first injection, to ensure good startability even at the time of cold start of the engine 1, and to prevent deterioration of exhaust gas. it can.

Embodiment 2. FIG.
In the first embodiment, the initial sequential injection is performed even when the fuel is not heated by the fuel heating control means 33 during the initial injection when the engine 1 is started. However, the present invention is not limited to this. .
Hereinafter, a description will be given of what injects fuel into all the cylinders 2 at the same time when the fuel is not heated by the fuel heating control means 33 at the time of initial injection at the start of the engine 1.

FIG. 7 is a block diagram showing a detailed configuration of the fuel injection control means 34A together with the fuel heating control means 33 in the control apparatus for an internal combustion engine according to Embodiment 2 of the present invention.
In FIG. 7, the fuel injection control unit 34 </ b> A includes an initial sequential injection control unit 41, a first initial injection control switching unit 42, and an all-cylinder simultaneous injection control unit 43.

The first initial injection control switching means 42 determines whether or not the heating operation of the delivery pipe heater 14 has been executed once by the fuel heating control means 33. Further, the first initial injection control switching means 42 performs either the initial sequential injection by the initial sequential injection control means 41 or the all cylinder simultaneous injection by the all cylinder simultaneous injection control means 43 according to the determination result. Switch.
The all-cylinder simultaneous injection control means 43 simultaneously injects fuel from each of the four injectors 12 a to 12 d to all the cylinders 2 at the time of initial injection of the injector 12 when the engine 1 is started.
Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

Hereinafter, the fuel injection operation at the start of the engine 1 in the control apparatus for an internal combustion engine having the above-described configuration will be described.
First, the initial injection routine by the fuel heating control means 33 and the fuel injection control means 34A will be described with reference to the flowchart of FIG. Note that the description of the same operation as in the first embodiment is omitted.

  First, the fuel injection control means 34A is determined to be immediately after key-on (Yes in step S101), and after setting the initial injection execution flag Fs to 1 (step S103), 0 is initialized to initialize the heater-on flag Fh. (Step S109).

  Subsequently, the fuel heating control means 33 determines that the fuel heating control condition is satisfied (Yes in step S104), energizes the delivery pipe heater 14 (step S105), and then energizes the delivery pipe heater 14. Is stored, the heater on flag Fh is set to 1 (step S110).

Next, when it is determined that the initial injection execution flag Fs is set to 1 (Yes in step S107), the fuel injection control unit 34A determines whether the heater on flag Fh is set to 1. (Step S111).
If it is determined in step S111 that the heater-on flag Fh is set to 1 (that is, Yes), the fuel injection control unit 34A uses the initial sequential injection control unit 41 to perform the initial sequential injection shown in FIG. The routine is executed (step S108), and the process returns to the main routine.

On the other hand, if it is determined in step S111 that the heater on flag Fh is not set to 1 (ie, No), the fuel injection control means 34A is shown in FIG. An all-cylinder simultaneous injection routine is executed (step S112), and the process returns to the main routine.
Here, this step S111 fulfills the function of the first initial injection control switching means 42.

Next, the all cylinder simultaneous injection routine by the all cylinder simultaneous injection control means 43 will be described with reference to the flowchart of FIG. This operation is executed as a subroutine in step S112 of the flowchart of FIG.
Note that the initial sequential injection routine by the initial sequential injection control means 41 is the same as that in the first embodiment described above, and a description thereof will be omitted.

First, the all-cylinder simultaneous injection control means 43 performs fuel injection from the first injector 12a to the fourth injector 12d (steps S301 to S304).
Next, the all cylinder simultaneous injection control means 43 sets the initial injection execution flag Fs to 0 (step S305) because the fuel injection has been completed for all the cylinders 2, and returns to the initial injection routine and the main routine.

Here, the simultaneous injection of all the cylinders at the start of the engine 1 described so far will be described with reference to FIG.
FIG. 10 is an explanatory view showing all-cylinder simultaneous injection in the control device for an internal combustion engine according to Embodiment 2 of the present invention. In FIG. 10, the delivery pipe heater is omitted.

In FIG. 10, when all cylinders are simultaneously injected when the engine 1 is started, the vicinity of the delivery pipe 13 and the injectors 12a to 12d is filled with unheated fuel immediately before the first injection.
Here, when fuel is simultaneously injected from each of the four injectors 12a to 12d for all the cylinders 2, unheated new fuel reaches the injector 12 near the inlet of the delivery pipe 13 during the initial injection. .

  However, since the fuel is not heated by the fuel heating control means 33 at this time, the fuel temperature in the delivery pipe 13 becomes equal to the temperature of the fuel supplied from the fuel pipe 15. Therefore, even when unheated new fuel is used for the first injection by the simultaneous injection of all cylinders, there is no difference in the temperature of the fuel injected into each cylinder 2.

According to the control apparatus for an internal combustion engine according to the second embodiment of the present invention, the fuel injection control means 34A is configured such that when the fuel is heated by the fuel heating control means 33 during the initial injection at the start of the engine 1, The initial sequential injection by the initial sequential injection control means 41 is performed. Further, the fuel injection control means 34A performs all cylinders simultaneous injection by the all cylinders simultaneous injection control means 43 when the fuel is not heated by the fuel heating control means 33 during the initial injection at the start of the engine 1.
Therefore, since the time until the end of the first injection for all the cylinders 2 can be shortened, the start time until the internal combustion engine starts up can be shortened, and the startability can be improved.

Embodiment 3 FIG.
In the second embodiment, when the fuel is heated by the fuel heating control means 33 during the initial injection at the start of the engine 1, the initial sequential injection is performed and the fuel is not heated by the fuel heating control means 33. However, the present invention is not limited to this.
Hereinafter, when the fuel is heated by the fuel heating control means 33 during the initial injection of the injector 12 at the start of the engine 1 and the initial injection amount at the initial injection is equal to or greater than a predetermined fuel injection amount, the initial sequential injection is performed. A description will be given of the case where all the cylinders are simultaneously injected when the fuel is heated by the fuel heating control means 33 and the initial injection amount at the initial injection is less than the predetermined fuel injection amount.

FIG. 11 is a block diagram showing a detailed configuration of the fuel injection control means 34B in the control apparatus for an internal combustion engine according to the third embodiment of the present invention together with the fuel heating control means 33.
In FIG. 11, the fuel injection control means 34B has an initial sequential injection control means 41, a first initial injection control switching means 42, an all-cylinder simultaneous injection control means 43, and a second initial injection control switching means 44. ing.

The second initial injection control switching means 44 is provided after the first initial injection control switching means 42, and the initial injection amount at the initial injection set according to the cooling water temperature Tw is a predetermined fuel injection set in advance. It is determined whether or not the amount is greater than or equal to the amount. Further, the second initial injection control switching means 44 performs either the initial sequential injection by the initial sequential injection control means 41 or the all cylinder simultaneous injection by the all cylinder simultaneous injection control means 43 according to the determination result. Switch.
Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

Hereinafter, the fuel injection operation at the start of the engine 1 in the control apparatus for an internal combustion engine having the above-described configuration will be described.
First, the initial injection routine by the fuel heating control means 33 and the fuel injection control means 34B will be described with reference to the flowchart of FIG. The description of the same operation as that of the second embodiment is omitted.

First, when it is determined that the heater on flag Fh is set to 1 (Yes in step S111), the fuel injection control unit 34B determines that the initial injection amount at the initial injection of the injector 12 is the threshold value Dp. It is determined whether or not (predetermined fuel injection amount) or more (step S113). Here, the threshold value Dp is the amount of fuel from the entrance of the delivery pipe 13 to the front of the first injector 12a.
In step S113, if it is determined that the initial injection amount at the time of the initial injection is equal to or greater than the threshold value Dp (that is, Yes), the fuel injection control means 34B uses the initial sequential injection control means 41 in FIG. The initial sequential injection routine shown is executed (step S108), and the process returns to the main routine.

On the other hand, if it is determined in step S113 that the initial injection amount at the time of the initial injection is less than the threshold value Dp (that is, No), the fuel injection control means 34B uses the all-cylinder simultaneous injection control means 43 to The all cylinders simultaneous injection routine shown in FIG. 9 is executed (step S112), and the process returns to the main routine.
Here, this step S113 fulfills the function of the second initial injection control switching means 44.

Here, the simultaneous injection of all cylinders when the fuel is heated by the fuel heating control means 33 and the initial injection amount at the initial injection is determined to be less than the threshold value Dp will be described with reference to FIG.
FIG. 13 is an explanatory diagram showing simultaneous injection of all cylinders when the fuel is heated and the initial injection amount is determined to be less than the threshold value Dp in the control apparatus for an internal combustion engine according to Embodiment 3 of the present invention. is there. In FIG. 13, the delivery pipe heater is omitted.

  In FIG. 13, when the initial injection at the time of cold start of the engine 1 is performed, the fuel is heated by the delivery pipe heater 14, and immediately before the initial injection, the vicinity of the delivery pipe 13 and the injectors 12a to 12d is filled with the heated fuel. Yes. The fuel pipe 15 connected to the inlet of the delivery pipe 13 is filled with unheated fuel.

Here, as described above, the initial injection amount is set according to the cooling water temperature Tw. Therefore, depending on the cooling water temperature Tw, the fuel heating control means 33 needs to heat the fuel, but the initial injection amount is set to be small. There may be.
Therefore, in the case where the fuel is heated and the initial injection amount is determined to be less than the threshold value Dp, the simultaneous injection of all the cylinders delivers the unheated new fuel even if the fuel is injected into all the cylinders 2 at the same time. The first injector 12a closest to the inlet of the pipe 13 is not reached. That is, unheated new fuel is not injected from the first injector 12a closest to the inlet of the delivery pipe 13.

According to the control apparatus for an internal combustion engine according to Embodiment 3 of the present invention, the fuel injection control means 34B is configured such that the fuel is heated by the fuel heating control means 33 and the initial injection is performed at the time of the initial injection at the start of the engine 1. When the initial injection amount at that time is equal to or greater than the predetermined fuel injection amount, the initial sequential injection by the initial sequential injection control means 41 is performed. Further, the fuel injection control unit 34B is configured such that when the fuel is heated by the fuel heating control unit 33 during the initial injection at the start of the engine 1 and the initial injection amount at the initial injection is less than a predetermined fuel injection amount, All cylinders simultaneous injection by the all cylinders simultaneous injection control means 43 is performed.
Therefore, the initial sequential injection can be performed only when there is a possibility that unheated new fuel is injected during the simultaneous injection of all cylinders, and the simultaneous injection of all cylinders can be performed in other cases.
Therefore, since the time until the end of the first injection for all the cylinders 2 can be shortened, the start time until the internal combustion engine starts up can be shortened, and the startability can be improved.

In the first to third embodiments, the fuel pipe 15 is connected to the end portion of the delivery pipe 13 in the length direction, and the first injector 12a to the fourth injector 12d in order from the injector 12 close to the inlet of the delivery pipe 13. However, it is not limited to this.
For example, as shown in FIG. 14, the fuel pipe 15 may be connected to an intermediate portion in the length direction of the delivery pipe 13.

  Here, when there are a plurality of injectors having the same distance from the inlet of the delivery pipe 13, for example, as shown in FIG. 14A, the first injectors 12 a to 12 a in order from the injector 12 close to the inlet of the delivery pipe 13. The fourth injector 12d is used, and the first sequential injection is performed in the order of the first injector 12a to the fourth injector 12d. Thus, as in the first to third embodiments, unheated fuel is prevented from reaching the injector 12 during the initial injection, and good startability is ensured even when the engine 1 is cold. In addition, the deterioration of exhaust gas can be prevented.

  When there are a plurality of injectors having the same distance from the inlet of the delivery pipe 13, for example, as shown in FIG. 14B, the two injectors 12 are gathered in order from the injector 12 that is closer to the inlet of the delivery pipe 13. The first injector 12a and the second injector 12b are used, and the first sequential injection is performed in the order of the first injector 12a to the second injector 12b. Thus, as in the first to third embodiments, unheated fuel is prevented from reaching the injector 12 during the initial injection, and good startability is ensured even when the engine 1 is cold. In addition, the deterioration of exhaust gas can be prevented.

1 is a configuration diagram illustrating an entire system including a control device for an internal combustion engine according to Embodiment 1 of the present invention. FIG. It is a block diagram which shows the injector, delivery pipe, and delivery pipe heater in the control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention. It is a block diagram which shows the detailed structure of the fuel-injection control means in the control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention with a fuel heating control means. 3 is a flowchart showing an initial injection routine by a fuel heating control means and a fuel injection control means of the control apparatus for an internal combustion engine according to the first embodiment of the present invention. 3 is a flowchart showing an initial sequential injection routine by an initial sequential injection control means of the control apparatus for an internal combustion engine according to the first embodiment of the present invention. It is explanatory drawing which shows the first sequential injection of the control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention. It is a block diagram which shows the detailed structure of the fuel-injection control means in the control apparatus of the internal combustion engine which concerns on Embodiment 2 of this invention with a fuel heating control means. It is a flowchart which shows the first-injection routine by the fuel heating control means and fuel-injection control means of the control apparatus of the internal combustion engine which concerns on Embodiment 2 of this invention. It is a flowchart which shows the all cylinders simultaneous injection routine by the all cylinders simultaneous injection control means of the control apparatus of the internal combustion engine which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows all the cylinders simultaneous injection of the control apparatus of the internal combustion engine which concerns on Embodiment 2 of this invention. It is a block diagram which shows the detailed structure of the fuel-injection control means in the control apparatus of an internal combustion engine in Embodiment 3 of this invention with a fuel heating control means. It is a flowchart which shows the first-injection routine by the fuel heating control means and fuel-injection control means of the control apparatus of the internal combustion engine which concerns on Embodiment 3 of this invention. In the control apparatus for an internal combustion engine according to Embodiment 3 of the present invention, it is an explanatory view showing all-cylinder simultaneous injection when the fuel is heated and the initial injection amount is determined to be less than a threshold value. It is another block diagram which shows the injector, delivery pipe, and delivery pipe heater in the control apparatus of the internal combustion engine which concerns on Embodiment 1-3 of this invention. It is explanatory drawing which shows the fuel-injection state at the time of performing all-cylinder simultaneous injection control in the conventional fuel heating control apparatus of an internal combustion engine.

Explanation of symbols

  12, 12a to 12d Injector, 13 Delivery pipe, 14 Delivery pipe heater, 33 Fuel heating control means, 34, 34A, 34B Fuel injection control means, 41 Initial sequential injection control means, 42 First initial injection control switching means, 43 All cylinders Simultaneous injection control means, 44 second initial injection control switching means;

Claims (3)

A plurality of injectors for injecting fuel into each of a plurality of cylinders of the internal combustion engine;
A delivery pipe for distributing the fuel to the plurality of injectors;
A delivery pipe heater for heating the fuel in the delivery pipe;
Fuel heating control means for controlling the operation of the delivery pipe heater;
Fuel injection control means for controlling injection of the fuel from the plurality of injectors,
The fuel injection control means injects the fuel heated in order from the injector closest to the inlet of the delivery pipe when the fuel is heated by the fuel heating control means during the initial injection of the plurality of injectors. A control device for an internal combustion engine. The fuel injection control means, at the time of initial injection of the plurality of injectors,
Injector closest to the inlet of the delivery pipe when the fuel is heated by the fuel heating control means and the initial injection amount at the initial injection set according to the coolant temperature is equal to or greater than a predetermined fuel injection amount Inject the heated fuel in order from
When the fuel is heated by the fuel heating control means and the initial injection amount at the initial injection set according to the coolant temperature is less than a predetermined fuel injection amount, the plurality of injectors simultaneously The control device for an internal combustion engine according to claim 1, wherein fuel is injected.   The fuel injection control means simultaneously injects the fuel from each of the plurality of injectors when the fuel is not heated by the fuel heating control means at the time of initial injection of the plurality of injectors. The control apparatus for an internal combustion engine according to claim 1 or 2.

Images