JP2000154744A - Fuel injection quantity control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection quantity control device of an internal combustion engine capable of supplying a desired quantity of fuel to an engine in the middle of warming-up. SOLUTION: A flank angle sensor 20 detects engine revolutionary speed, and a pressure sensor 26 detects pressure of a suction pipe. An ECU 30 computes basic injection time with warming-up completion time as a standard in accordance with engine revolutionary speed and suction pipe pressure. The ECU 30 judges whether a suction system of the engine 1 is warmed up or not at the time of low temperature starting of the engine 1. Additionally, the ECU 30 sets a correction factor to the quantity increasing side small as intake air quantity passing a suction pipe 10 becomes larger as basic fuel injection quantity per hour is larger and corrects fuel injection quantity to the quantity increasing side by using the correction factor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control device for an internal combustion engine, and more particularly to a fuel injection amount control device for an internal combustion engine that controls the fuel injection amount according to the temperature of air taken into the engine. It is.

[0002]

2. Description of the Related Art As a fuel injection amount control device for an engine,
There is a so-called DJ type fuel injection amount control device that controls the fuel injection amount based on the engine speed and the intake pipe pressure. In a device employing this DJ method, for example, a surge tank constituting an intake pipe is provided with a pressure sensor for detecting an intake air amount. For example, an external air cleaner is provided in an air cleaner on an upstream side of the intake pipe. An intake air temperature sensor for detecting a temperature is provided. In this configuration, the engine temperature rises during warm-up when the engine is started from a cold state, so that the density of intake air supplied to the engine changes. Therefore, the fuel injection amount is controlled by correcting the density change according to the temperature of the intake air.

A method for correcting the density of intake air based on the temperature of engine cooling water is disclosed in Japanese Patent Publication No. 3-12217. In this method, a basic fuel injection amount (basic injection time) at the completion of warm-up is calculated based on the engine speed and the intake pipe pressure. Then, the temperature of the intake air taken in from the outside air is detected, and the lower the intake air temperature is, the more the basic fuel injection amount is corrected to the increase side. Further, the temperature (cooling temperature) of the cooling water of the engine is detected, and the lower the coolant temperature, the more the basic fuel injection amount is corrected to the increasing side.

That is, the lower the intake air temperature and the water temperature, the lower the intake air supplied to the engine through the intake pipe, and the higher the density of intake air supplied to the engine. Done.

[0005]

However, for example, when the accelerator pedal is depressed during warm-up and the amount of intake air increases, the temperature of the intake air passing through the intake pipe is lower than when the accelerator depression is zero. The degree of rise is different. Therefore, optimal intake density correction cannot be performed. That is, the injection amount correction based on the intake air density is not performed, and the desired fuel amount cannot be supplied to the engine.

Incidentally, a technique for estimating the intake air temperature when passing through an intake pipe based on the amount of intake air is disclosed in Japanese Patent Laid-Open No. 8-151.
No. 942, this technology discloses that
The intake air temperature sensor is omitted, the intake air temperature is estimated based on the temperature of the engine cooling water, and the fuel injection amount is corrected. In this configuration, if the engine is stopped and restarted before the engine is sufficiently cooled, the rise in the intake air temperature cannot be accurately estimated, and the fuel injection amount is not correctly corrected.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide an internal combustion engine capable of supplying a desired amount of fuel to the engine during warm-up of the engine. It is to provide a fuel injection amount control device.

[0008]

In order to achieve the above object, the invention according to claim 1 detects an engine speed and an intake pipe pressure, and detects the detected engine speed and the intake pipe pressure. A fuel injection amount control device that controls the fuel injection amount in accordance with the following formula: a warm-up determination unit that determines whether the engine intake system has been warmed up when the internal combustion engine is started; When it is determined that the engine is not yet warmed up, the correction amount toward the increasing side is set to be smaller as the load is higher and the engine speed is higher, based on the load state and the rotation speed of the internal combustion engine, and the fuel injection is performed based on the set correction amount. The gist of the invention is to provide a load state correcting means for correcting the amount.

When the internal combustion engine is started from a cold state, the engine intake system is not warmed up at the beginning of the start,
For example, the wall temperature of the intake pipe is low. Therefore, when the intake air passes through the intake pipe, the intake air density increases due to the low intake air temperature, and the fuel injection quantity control device of the type that controls the fuel injection quantity from the engine speed and the intake pipe pressure. An increase correction regarding the air density is required. For example, when the intake air density increases, the fuel injection amount is corrected to the increasing side. Also, at this time, if the load condition of the internal combustion engine is different, the amount of intake air passing through the intake pipe changes, and the degree of temperature rise when the intake air flows from the upstream side to the downstream side of the intake pipe according to the intake air amount. different.

According to the configuration of the first aspect, the higher the load and the higher the rotation speed (that is, the higher the intake air amount), the smaller the correction amount to the increase side is set, and the fuel injection amount is corrected by the set correction amount. By doing so, even if the load state changes at a low temperature start of the internal combustion engine and the degree of temperature rise of the intake air when passing through the intake pipe changes accordingly and the intake air density changes,
The injection amount can be corrected in accordance with the change in the intake air density. As a result, a desired amount of fuel can be supplied to the engine during warm-up of the internal combustion engine.

According to a second aspect of the present invention, in the fuel injection amount control device for an internal combustion engine according to the first aspect, an intake air temperature detecting means for detecting an intake air temperature at an upstream portion of the intake pipe, Intake pipe corresponding temperature detecting means for detecting a corresponding temperature; and intake correcting means for correcting the fuel injection amount to an increasing side as the intake air temperature is lower and correcting the fuel injection amount to an increasing side as the intake pipe corresponding temperature is lower. The main point is to have the following.

According to this configuration, the fuel injection amount is corrected to be increased as the intake air temperature is lowered by the intake correction means, and the fuel injection amount is corrected to be increased as the intake pipe corresponding temperature is lowered. As a result, the density correction of the intake air supplied to the engine is accurately performed. Incidentally, even when the engine is restarted, the fuel injection amount is corrected based on the load state of the engine, the intake air temperature upstream of the intake pipe, and the intake pipe corresponding temperature, so that a desired amount of fuel is supplied to the engine. Is done.

According to a third aspect of the present invention, in the fuel injection amount control device for an internal combustion engine according to the first or second aspect, the basic fuel injection amount corresponding to the engine speed and the intake pipe pressure is set to a load state. The gist is that the correction means sets the correction amount to the increasing side to be smaller as the basic fuel injection amount per time is larger, and corrects the fuel injection amount with the set correction amount. It is.

According to this configuration, as the basic fuel injection amount per time, that is, the intake air amount increases, the correction amount toward the increasing side is set smaller by the load state correction means, and the fuel injection amount is set based on the set correction amount. The amount is corrected. For example, even if the basic fuel injection amount changes, the degree of temperature rise of the intake air when passing through the intake pipe changes accordingly, and the intake air density changes, the injection amount correction based on the change in the intake air density can be corrected. It becomes possible.

According to a fourth aspect of the present invention, in the fuel injection amount control device for an internal combustion engine according to the third aspect, the basic fuel injection amount is set based on a warm-up completion state of the engine intake system. The gist is that it is a quantity.

According to this configuration, the basic fuel injection amount is set in a warm-up completion state in which the temperature of the engine intake system is saturated at a high temperature. That is, the basic fuel injection amount is set in a warm-up completion state in which the temperature of the intake pipe is stable as compared with a low temperature when the temperature of the intake pipe changes at each time. Therefore, variation factors at the time of engine adaptation are reduced, so that more accurate injection amount control can be performed. Further, since the basic fuel injection amount is set on the basis of the completion of the warm-up, it is not necessary to perform the correction by the load state correcting means when the warm-up is completed, so that the processing load of the fuel injection amount control device can be reduced.

According to a fifth aspect of the present invention, in the fuel injection amount control device for an internal combustion engine according to any one of the first to fourth aspects, an integrated value for calculating an integrated value of a load from the time of starting the engine. The load state correction means includes increasing the fuel injection amount in accordance with the calculated integrated load value.

After the engine is started, the temperature of the engine intake system gradually increases, and the density of the intake air also changes. In this case, the load integrated value from the start of the engine is obtained as described above, and the fuel injection amount is increased and corrected in accordance with the load integrated value, so that an appropriate value can be obtained during the period from immediately after the start of the engine to the completion of the warm-up of the intake system. It is possible to perform a proper injection amount correction.

According to a sixth aspect of the present invention, in the fuel injection amount control apparatus for an internal combustion engine according to any one of the first to fourth aspects, an integrated value for calculating an integrated value of a load from the time of starting the engine. Means, the load state correction means, by increasing the fuel injection amount according to the calculated load integrated value,
The gist of the gist is to determine that the warm-up of the engine intake system has been completed when the calculated load integrated value reaches a predetermined value.

According to this configuration, the warm-up completion timing is variably set according to the load condition at each time. For example, when a relatively low load state is continued at the time of engine start, the timing of warm-up completion is delayed, and when a relatively high load state is continued at the time of engine start, the warm-up completion timing is advanced. . In this case, the timing of the completion of the warm-up and the timing at which the correction by the correction unit becomes unnecessary coincide with each other,
Since the correction is canceled at an appropriate timing, correction without excess or deficiency can be performed.

According to a seventh aspect of the present invention, in the fuel injection amount control device for an internal combustion engine according to any one of the first to sixth aspects, the invention is applied to an internal combustion engine mounted on a vehicle, and the vehicle travels. The gist is that a traveling wind determination unit that determines the strength of the traveling wind at the time and a traveling wind correction unit that corrects the fuel injection amount based on the traveling wind intensity determined by the traveling wind determination unit are provided. Is what you do.

An intake pipe for supplying intake air to the engine is cooled by traveling wind when the vehicle is traveling. According to the above configuration,
Since the injection amount is corrected based on the strength of the traveling wind, the fuel injection amount according to the degree of cooling of the intake pipe can be supplied to the engine.

In the invention according to claim 8, in the fuel injection amount control device for an internal combustion engine according to claim 2, the intake pipe corresponding temperature detecting means is a water temperature sensor for detecting a temperature of engine cooling water, The gist of the warm-up determining means is to determine that the warm-up of the engine intake system has been completed when a predetermined time has elapsed after the temperature of the cooling water has reached a predetermined temperature.

During a cold start of the internal combustion engine, the temperature of the cooling water rises with the operation of the engine and reaches a predetermined holding temperature. At that time, however, the temperature of the intake pipe has not reached the high-temperature saturation point. The machine is in a state before completion. For this reason, as described above, if it is determined that the warm-up of the engine intake system has been completed when a predetermined time has elapsed after the temperature of the engine cooling water has reached the predetermined temperature, the timing of the warm-up completion is accurately determined. it can. In other words, because the correction is canceled at the appropriate time,
The injection amount can be accurately corrected.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of a fuel injection amount control device for an internal combustion engine according to the present invention will be described below with reference to the drawings. In the present embodiment, a fuel injection system that controls a fuel injection amount based on an intake pipe pressure detected by a pressure sensor is employed.

FIG. 1 is a schematic configuration diagram of an engine system including a fuel injection amount control device according to the present embodiment. As shown in FIG. 1, an engine 1 as a four-cycle multi-cylinder internal combustion engine includes a cylinder block 2, in which a plurality of cylinders 4 including a combustion chamber 3 are formed. The injector 5 injects fuel toward an intake port 6 provided in the cylinder 4. The ignition plug 7 provided in the cylinder 4 ignites the mixture supplied to the combustion chamber 3.

More specifically, in the intake stroke of the engine 1, when the intake valve 6 is opened by the intake valve 8, the mixture of the air flowing into the intake pipe 10 through the air cleaner 9 and the fuel injected from the injector 5 is mixed. Air flows into the combustion chamber 3. In the compression stroke of the engine 1, the air-fuel mixture in the combustion chamber 3 is pressurized by the upward movement of the piston 11, ignited by the spark plug 7 and exploded and burns, whereby the piston 11 moves downward and the crankshaft 12 rotates. Thus, the driving force of the engine 1 is obtained. In the exhaust stroke of the engine 1, the exhaust valve 13 opens the exhaust port 13 so that the combustion chamber 3
The exhaust gas generated in the step is guided to the exhaust pipe 15 and discharged to the outside.

A crank angle sensor 20 is provided close to the crankshaft 12, and the rotational speed NE of the engine 1 is calculated based on a detection signal of the sensor 20. The water temperature sensor 21 provided in the cylinder block 2 detects the temperature (water temperature) THW of the cooling water flowing inside the block 2 to cool the block 2, and outputs a signal corresponding to the water temperature THW. The cooling water circulates in a circulation path (not shown). At this time, the cooling water is controlled to a predetermined temperature, for example, approximately 80 ° C. by the function of the thermostat.

An intake air temperature sensor 22 is provided in the air cleaner 9 provided upstream of the intake pipe 10 and detects the intake air temperature THA. In addition,
Since the inside of the air cleaner 9 is hardly affected by the engine temperature, the value detected by the intake air temperature sensor 22 is considered to match the outside air temperature. A throttle valve 23 provided in the intake pipe 10 opens and closes the intake pipe 10 based on an accelerator operation. By operating the throttle valve 23, the amount of air flowing through the intake pipe 10, that is, the amount of intake air is adjusted. A throttle sensor 24 provided near the throttle valve 23 detects the opening (throttle opening) of the valve 23 and outputs a signal corresponding to the opening.

The intake pipe 10 is provided with a surge tank 25 for smoothing the pulsation of the intake air. The surge tank 25 detects an intake pressure (intake pipe pressure) PM in the surge tank 25. A pressure sensor 26 is provided. The surge tank 25 is connected to each cylinder of the engine 1 via an intake manifold 27.

An oxygen sensor 28 provided in the exhaust pipe 15 detects the concentration of oxygen remaining in the exhaust gas, and outputs a signal corresponding to the concentration. Further, a vehicle speed sensor 29 is provided near a transmission (not shown), and detects a traveling speed (vehicle speed) SPD of the vehicle.

The electronic control unit (ECU) 30 includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), a timer for measuring time, and the like. Signals from the various sensors 20, 21, 22, 24, 26, 28, and 29 described above are input to the ECU 30, and the ECU 30 controls the fuel injection amount by the injector 5 based on these signals. The control program and data used in each process are stored in ROM
Is stored in advance.

In this embodiment, the intake air temperature sensor 22 is used as the intake air temperature detecting means, and the water temperature sensor 21 is used as the intake pipe corresponding temperature detecting means. Further, the water temperature THW of the engine 1 corresponds to a temperature corresponding to the temperature of the intake pipe 10.

Next, of the processing executed by the ECU 30, the fuel injection amount (fuel injection time) by the injector 5
The process for calculating is described with reference to FIG. First, at step 100, the ECU 30 uses the water temperature sensor 21 and the intake air temperature sensor 22 to take in the water temperature THW and the intake air temperature THA. Then, in step 101, the ECU 30 calculates the intake air temperature correction coefficient FTHA from a table using the intake air temperature THA as a parameter as shown in FIG.
Ask for o. In FIG. 3, as the intake air temperature THA increases, the intake air temperature correction coefficient FTHAo decreases, and the intake air temperature THA increases.
When A = 20 ° C., the intake air temperature correction coefficient FTHAo = 1. The lower the intake air temperature THA in the air cleaner 9, the lower the intake air temperature when the intake air passes through the intake pipe 10 and reaches the inside of the surge tank 25, so that the density of the intake air increases. Accordingly, since the fuel injection amount is increased as the intake air temperature THA is lower, the intake air temperature correction coefficient FTHAo is increased.

Then, in step 102, the ECU 30 obtains a correction coefficient Kthw from a table using the water temperature THW as a parameter as shown in FIG. In FIG. 4, there is a relation that the correction coefficient Kthw becomes smaller as the water temperature THW becomes higher.
It becomes 1. Correction coefficient Kthw when water temperature THW = 80 ° C.
= 1 because the water temperature THW = 8 which is controlled to be substantially constant by the thermostat after the engine 1 is warmed up
This is because the temperature at 0 ° C. is used as a reference. Water temperature THW is 80
C., the wall temperature of the intake pipe 10 is also low,
Since the rise in the intake air temperature when passing through 0 is small, the intake air temperature in the surge tank 25 becomes lower than when the warm-up of the intake system is completed (complete warm-up). Therefore, in order to increase the fuel injection amount as the water temperature THW is lower, the correction coefficient Kthw is increased.

In step 103, the ECU 30 takes in the intake pipe pressure PM and the engine speed NE by using the pressure sensor 26 and the crank angle sensor 20. And
The ECU 30 determines in step 104 that the intake pipe pressure PM
And a basic injection time (basic fuel injection amount) T according to the intake air amount from a map using the engine speed NE as a parameter.
Calculate P. In the map for obtaining the basic injection time TP, values are set in a warm-up completion state in which the state of the engine 1 is stable.

Thereafter, in step 105, the ECU 30 determines whether or not the warm-up of the intake system has been completed. Here, completion of warm-up is determined by elapse of a predetermined time T from when the water temperature THW reaches 80 ° C. That is, the water temperature THW is
The temperature of the intake system of the engine 1 is controlled to be 80 ° C. by the thermostat.
, The temperature continues to rise to a predetermined saturation temperature. Therefore, the time at which this temperature is saturated is predicted by the predetermined time T. The predetermined time T becomes longer as the intake air temperature THA becomes lower as shown in FIG. Further, the lower the intake air temperature THA, the larger the change rate of the predetermined time T with respect to the change of the intake air temperature THA. In this manner, in the present embodiment, a complete warm-up state in which the temperature rise of the intake system of the engine 1, that is, the intake pipe 10 downstream of the air cleaner 9 is saturated is determined.

If the ECU 30 determines in step 105 that the engine is being warmed up, the process proceeds to step 106 to calculate a basic fuel injection amount per time. here,
The basic fuel injection amount per time is a value (TP × NE) calculated by multiplying the basic injection time TP by the engine speed NE.
/ 2), which is a parameter corresponding to the intake air amount. Then, the correction coefficient Ktp is calculated from the table shown in FIG. 6 using the basic fuel injection amount per time as a parameter. In FIG. 6, the correction coefficient Ktp increases as the basic fuel injection amount per time decreases. Further, the smaller the basic fuel injection amount per time is, the larger the change rate of the correction coefficient Ktp with respect to the change in the basic fuel injection amount per time is.

In this case, as the basic fuel injection amount per hour is smaller, the amount of intake air passing through the intake pipe 10 is reduced, and as the amount of intake air is smaller, the intake air is discharged from the surge tank 2.
The degree of temperature rise until the temperature reaches 5 increases. Therefore,
The correction coefficient Ktp is set to be larger than 1 in order to increase the fuel injection amount as the intake air amount decreases.

On the other hand, if it is determined in step 105 that the warm-up has been completed, the ECU 30 proceeds to step 107.
In step 108, after setting the correction coefficient Ktp = 1,
Move to

Then, in step 108, the ECU 30 calculates a final intake air temperature correction coefficient FTHA by the following equation (1). FTHA = FTHAo × Kthw × Ktp (1) Next, in step 109, the ECU 30 calculates the final injection time TAU by the following equation (2). TAU = TP × FTHA × α + TV (2) Here, α is an increase / decrease correction coefficient calculated from the sum or product of various coefficients. The various correction coefficients include a post-start increase, an output increase, and a feedback correction coefficient for the air-fuel ratio. TV is the invalid injection time of the injector 5.

Thereafter, in step 110, the ECU 30 stores the calculated final injection time TAU in the RAM, and ends this processing. Then, a drive signal corresponding to the final injection time TAU is output to the injector 5 by the ECU 30, the valve opening time of the injector 5 is controlled, and a predetermined amount of fuel is injected.

In this embodiment, step 1 in FIG.
Step 05 corresponds to the warm-up determination means.
Reference numerals 8 and 109 correspond to load state correction means. As described above, according to the present embodiment, the following effects can be obtained.

(1) The basic injection time TP is set as a parameter corresponding to the load state, and the larger the basic fuel injection amount per time, the smaller the correction coefficient Ktp to the increase side is set, and the fuel injection is performed by the set correction coefficient Ktp. The amount is corrected. Therefore, even when the intake air amount changes at the time of starting the engine 1 at a low temperature, the degree of temperature rise of the intake air in the intake pipe 10 changes accordingly, and the intake air density changes, the injection amount according to the change in the intake air density also changes. Correction becomes possible. As a result, a desired amount of fuel can be injected into the engine 1 during warm-up of the engine 1. As a result, accurate fuel is supplied to the engine 1 so as to achieve an ideal air-fuel ratio, so that exhaust emission is improved.

(2) Intake temperature T at the upstream of intake pipe 10
The lower the HA, the more the fuel injection amount is corrected to the increasing side, and the lower the water temperature THW, the more the fuel injection amount is corrected to the increasing side. As a result, the density correction of the intake air supplied to the engine 1 is accurately performed. Incidentally, even when the engine 1 is restarted, the basic fuel injection amount per hour and the intake air temperature T
Final intake air temperature correction coefficient FTH based on HA and water temperature THW
Since the fuel injection amount is corrected by A, the desired fuel amount can be supplied.

(3) Completion of warm-up is determined when a predetermined time T has elapsed since the water temperature THW reached a predetermined temperature (80 ° C.). The lower the outside air temperature is, the longer it takes for the engine 1 to be in the warm-up completion state. Therefore, the predetermined time T for determining the completion of warm-up is set to a longer time as the intake air temperature THA is lower. As a result, completion of warm-up is accurately determined, so that injection amount correction can be accurately performed during warm-up.

(4) The basic injection time TP is calculated based on the completion of the warm-up of the engine 1, and the fuel injection amount is corrected based on the basic injection time TP. In other words, the basic injection time T
P is set. Therefore, a variation factor at the time of engine adaptation can be reduced, and the fuel injection amount can be controlled more accurately. Further, since the basic injection time TP is set on the basis of the completion of the warm-up, when the warm-up is completed, Step 10 in FIG.
It is not necessary to perform the calculation processing of the correction coefficient Ktp of No. 6, and the correction coefficient Ktp may be set to 1 in step 107. Therefore, the processing load on the ECU 30 after the warm-up is completed can be reduced.

(Second Embodiment) Next, a second embodiment which embodies a fuel injection amount control device for an internal combustion engine according to the present invention will be described. In the present embodiment, the calculation of the final intake air temperature correction coefficient FTHA is different from that of the first embodiment. The configuration of the engine system in the present embodiment is as follows.
The description is omitted because it is the same as that of the first embodiment.

FIG. 7 is a timing chart showing a change in the required correction amount and a temperature change when the engine 1 is started at a low temperature. FIG. 7 shows the water temperature THW and the intake air temperature in the surge tank 25 (hereinafter referred to as the surge tank). Temperatures called THAs)
And the change.

As shown in FIG. 7, the temperature T in the surge tank
HAs rises later than the water temperature THW. The reason is that the heat generated from the engine 1 is changed to the cooling water → the cylinder block 2 → the intake manifold 27 → the surge tank 25
It is to be transmitted to etc.

The solid line in FIG. 7 shows the case where the engine 1 is warmed up in the idle state, and the one-dot chain line shows the case where the engine 1 is warmed up with the throttle opening = 10 deg. Specifically, when the load (intake air amount) of the engine 1 is relatively large and the throttle opening is 10 deg, the calorific value of the engine 1 is larger than in the idle state where the load is small, so the engine water temperature THW rises faster. ing. When the time from when the water temperature THW reaches 80 ° C. to when the rise in the surge tank temperature THAs is saturated is defined as the delay time Ttp, the throttle opening = 10
The deg delay time Ttp1 is equal to the idle delay time T
It is shorter than tp2 (Ttp1 <Ttp2). That is,
The delay time Ttp becomes shorter as the calorific value of the engine 1 becomes larger. The reason for this is that the greater the load, the greater the amount of heat generated by the engine 1, which is affected. The timing at which the rise in the temperature THAs in the surge tank is saturated is a complete warm-up (warm-up completion) state, and the timing for determining the completion of warm-up is earlier as the load is larger. That is, the temperature THAs in the surge tank that is heated when the intake air passes through the intake pipe 10 can be predicted from the calorific value of the engine 1.

Here, a calculation process in which the fuel injection amount is corrected based on the heat generation amount of the engine 1 will be described with reference to FIG. FIG. 8 is a flowchart illustrating a process of calculating the fuel injection amount, which is executed by the ECU 30 as in the first embodiment. In FIG. 8, the common parts with the fuel injection time calculation processing (FIG. 2) described above are omitted, and only the changed parts are shown. Steps 200 to 205 in FIG. 8 are executed in place of the processing of steps 105 to 108 in FIG.

In step 200, the ECU 30 calculates the integrated value CTP by integrating the basic fuel injection amount per time calculated in step 106 in FIG. In the following step 201, the ECU 30 determines whether or not the warm-up is completed. In the present embodiment, the warm-up completion is determined when the water temperature THW becomes 80 ° C. and the integrated value CTP becomes a predetermined value or more.

If the ECU 30 determines in step 201 that the engine is being warmed up, it proceeds to step 202.
Then, the correction coefficient Ktp is calculated from the table shown in FIG. 6 using the basic fuel injection amount per time as a parameter. Thereafter, in step 203, the ECU 30 calculates the correction coefficient Kctp from the table using the integrated value CTP shown in FIG. 9 as a parameter. In FIG. 9, the correction coefficient Kctp increases as the integrated value CTP decreases. Further, the smaller the integrated value CTP is, the larger the change rate of the correction coefficient Kctp with respect to the change of the integrated value CTP becomes.

Integrated value CT of basic fuel injection amount per hour
P corresponds to the calorific value of the engine 1, and the integrated value CTP increases as the warm-up of the engine 1 progresses. Engine 1
Is cold, the integrated value CTP is small, and the surge tank temperature THAs is low. Accordingly, in order to increase the fuel injection amount as the integrated value CTP decreases, the correction coefficient Kctp is increased. At the timing when the warm-up of the engine 1 is completed (complete warm-up), the correction coefficient Kctp corresponding to the increase of the integrated value CTP becomes 1 with the increase of the integrated value CTP.

On the other hand, if it is determined in step 201 that the warm-up has been completed, the ECU 30 proceeds to step 204.
, The process proceeds to step 205 after setting the correction coefficients Ktp = 1 and Kctp = 1.

Then, in step 205, the ECU 30 calculates the final intake air temperature correction coefficient FTHA by the following equation (3). FTHA = FTHAo × Kthw × Ktp × Kctp (3) Next, in step 109 shown in FIG. 2, the ECU 30 calculates the final injection time TAU by the above-described equation (2). Thereafter, a drive signal corresponding to the final injection time TAU is output to the injector 5 by the ECU 30, the valve opening time of the injector 5 is controlled, and a predetermined amount of fuel is injected.

The required correction amount in FIG. 7 is a correction amount based on the correction coefficients Kthw, Ktp, and Kctp described above. In this case, looking at the time of idling and the case where the throttle opening is 10 deg, when the throttle opening is 10 deg, the correction amount is smaller than that at the time of idling, but this is because the intake air amount becomes larger. This means that the lean amount differs depending on the intake air amount. This different lean amount can be corrected by performing the processing of steps 202 and 203 in FIG. That is, when fuel is injected without performing these corrections, the amount of fuel supplied to the engine 1 becomes insufficient, the air-fuel ratio shifts to the lean side, and the exhaust emission deteriorates.

Further, when idling and throttle opening = 10
In the case of deg, the timing of complete warm-up is different,
This is because the heat value of the engine 1 is different, and FIG.
, The timing of each complete warm-up can be determined.

In this embodiment, step 2 in FIG.
00 corresponds to the integrating means, and step 201 corresponds to the warm-up determining means. Steps 202, 203, 205
Corresponds to the load state correction means.

As described above, also in the present embodiment, the following effects can be obtained in addition to the effects similar to those of the first embodiment. (1) The temperature rise of the intake system of the engine 1 after the start is
It depends on the calorific value of the engine 1. Therefore, engine 1
Value C of basic fuel injection amount per hour from the start of fuel injection
TP is obtained, and the fuel injection amount is corrected according to the integrated value CTP. Therefore, an appropriate injection amount correction can be performed during a period from immediately after the start of the engine to the completion of the warm-up of the intake system.

(2) As shown in FIG. 7, the temperature THAs in the surge tank rises later than the water temperature THW, and even after the water temperature THW is maintained at a constant temperature (THW = 80 ° C.),
Continue rising until warm-up is complete. The timing of the completion of the warm-up depends on the calorific value of the engine 1. Therefore, the warm-up completion timing is variably set based on the integrated value CTP of the basic fuel injection amount per time. In other words, the timing of the completion of warm-up coincides with the timing of the correction coefficient Kctp = 1, and the correction is stopped at an appropriate timing.
Correction without excess or deficiency can be performed.

(Third Embodiment) Next, a description will be given of a third embodiment of the fuel injection amount control device for an internal combustion engine according to the present invention. In the present embodiment, the calculation of the final intake air temperature correction coefficient FTHA is different from the above embodiment. The configuration of the engine system in the present embodiment is as follows.
The description is omitted because it is the same as that of the first embodiment.

During traveling of the vehicle, the intake pipe 10 is cooled by the traveling wind flowing into the engine room. Therefore, the degree of temperature rise when the intake air passes through the intake pipe 10 varies depending on the strength of the traveling wind. That is, as the traveling wind increases, the intake pipe 10 is cooled, and the degree of temperature rise of the intake air decreases. In this case, the density of the intake air supplied to the engine 1 increases, so it is necessary to increase the fuel supplied to the engine 1.

Therefore, in the present embodiment, the fuel injection amount is corrected based on parameters relating to the traveling wind. FIG.
4 is a flowchart illustrating a process of calculating a fuel injection amount according to the present embodiment, in which common parts to the above-described fuel injection time calculation processing (FIG. 2) are omitted and only changed parts are shown. Steps 300 to 306 in FIG. 10 are executed in place of the processing of steps 105 to 108 in FIG.
In the present embodiment, as a parameter relating to the traveling wind, the ratio of the engine speed NE to the vehicle speed SPD, N /
The V ratio is used.

In step 300, the ECU 30 determines whether the warm-up is completed. In the present embodiment, the first
The determination is made based on the lapse of a predetermined time T after the water temperature reaches 80 ° C., as in the embodiment. The ECU 30 executes step 30
If it is determined in step 0 that warm-up is in progress, step 3
01, the correction coefficient Ktp is calculated from the table shown in FIG. 6 using the basic fuel injection amount per time as a parameter, and the routine proceeds to step 303. On the other hand, if it is determined in step 300 that the warm-up is completed, the ECU 30 sets the correction coefficient Ktp = 1 in step 302, and then proceeds to step 303.

The ECU 30 fetches the vehicle speed SPD in step 303 and proceeds to step 304 to
The N / V ratio is calculated based on the engine speed NE and the vehicle speed SPD taken in step 103. Then E
The CU 30 determines in step 305 the N /
The correction coefficient Knv is calculated from a table using the V ratio as a parameter. During high-speed traveling when traveling wind is strong, the shift position becomes the highest Hi gear position and the N / V ratio becomes the smallest. When the vehicle travels at low speed when the traveling wind is weak, the shift position is the low gear position and the N / V ratio is large. In FIG. 11, the correction coefficient Knv = 1 when the N / V ratio becomes the smallest, and the correction coefficient Knv becomes smaller as the N / V ratio increases. In other words, H at which the traveling wind becomes strong
The degree of temperature rise of the intake air in the intake pipe 10 decreases as the position of the i-gear increases, and the density of air supplied to the fuel chamber 3 of the engine 1 increases. Therefore, in order to increase the fuel injection amount as the N / V ratio decreases, the correction coefficient Knv is increased. However, when the vehicle speed SPD is 0 (when the vehicle is stopped), the correction coefficient Knv is calculated as the lowest Low gear.

Then, in step 306, the ECU 30 calculates a final intake air temperature correction coefficient FTHA by the following equation (4). FTHA = FTHAo × Kthw × Ktp × Knv (4) Next, in step 109 shown in FIG. 2, the ECU 30 calculates the final injection time TAU by the above-described equation (2). Thereafter, a drive signal corresponding to the final injection time TAU is output to the injector 5 by the ECU 30, the valve opening time of the injector 5 is controlled, and a predetermined amount of fuel is injected.

However, in the present embodiment, the basic injection time TP is calculated based on a map set at the Hi gear position where the traveling wind becomes strongest. The basic gear position is not limited to the Hi gear position as in the present embodiment, but may be the intermediate gear position or the Low gear position. In this case, the basic injection time TP may be calculated based on a map set at the intermediate gear position or the low gear position, and the correction coefficient Knv at the intermediate gear position or the low gear position may be set to 1.

In this embodiment, step 300 in FIG. 10 corresponds to the warm-up determination means, and steps 301 and 30 are performed.
Reference numeral 6 corresponds to the load state correction means. Step 30
4 corresponds to running wind determination means, and steps 305 and 306
Corresponds to the traveling wind correction means.

As described above, also in this embodiment, the following effects can be obtained in addition to the same effects as those of the above-described embodiment. (1) The fuel supplied to the engine 1 is corrected according to the strength of the traveling wind when the vehicle travels. Specifically, when the traveling wind is strong, the fuel supplied to the engine 1 is corrected to an increased amount. As a result, a desired amount of fuel can be supplied to the engine 1.

(Fourth Embodiment) Next, a description will be given of a fourth embodiment which embodies a fuel injection amount control device for an internal combustion engine according to the present invention. In the present embodiment, the calculation of the final intake air temperature correction coefficient FTHA is different from that of the above embodiment. The configuration of the engine system in the present embodiment is as follows.
The description is omitted because it is the same as that of the first embodiment.

The degree of cooling of the intake pipe 10 by the traveling wind differs depending on the temperature difference of the outside air. Therefore, in the present embodiment,
The fuel injection amount is corrected based on the parameters relating to the traveling wind and the intake air temperature THA. FIG. 12 is a flowchart showing a process for calculating the fuel injection amount in the present embodiment, in which the common parts with the above-described fuel injection time calculation process (FIG. 2) are omitted, and only the changed portions are shown. Steps 400 to 408 in FIG. 12 correspond to steps 105 to 108 in FIG.
The processing is executed in place of the above processing. In this embodiment, the vehicle speed SPD is used as a parameter related to the traveling wind, instead of the N / V ratio in the third embodiment.

In step 400, the ECU 30 calculates the integrated value CTP of the basic injection time TP in the same manner as in the second embodiment, and proceeds to step 401 to determine whether the warm-up is completed. In the present embodiment, the basic injection time TP
The completion of warm-up is determined based on whether or not the integrated value CTP has become equal to or greater than a predetermined value. If it is determined in step 401 that the engine is being warmed up, in step 402, the ECU 30 proceeds to step 402.
The correction coefficient Ktp is calculated from the table using the basic fuel injection amount per time as a parameter shown in FIG. Then, the ECU 30 calculates the correction coefficient Kctp from the table using the integrated value CTP of the basic fuel injection amount per time shown in FIG. 9 as a parameter, and proceeds to step 405. On the other hand, if it is determined in step 401 that the warm-up is completed, the ECU 30 proceeds to step 404
After setting the correction coefficients Ktp = 1 and Kctp = 1, step 4
Move to 05.

In step 405, the ECU 30 fetches the vehicle speed SPD.
The correction coefficient Kspd is calculated from a table using the vehicle speed SPD as a parameter as shown in FIG. In FIG. 13, the vehicle speed SP
When D = 0, Kspd = 1, and as the vehicle speed SPD increases, the correction coefficient Kspd increases. That is, the vehicle speed SP
As D becomes faster and the traveling wind becomes stronger, the intake pipe 10 is cooled, so that the degree of temperature rise of the intake air in the intake pipe 10 becomes smaller and the density of the air supplied to the fuel chamber 3 of the engine 1 becomes higher. Accordingly, in order to increase the fuel injection amount as the vehicle speed SPD increases, the correction coefficient Kspd is increased.

Further, in step 407, the ECU 30 calculates a correction coefficient Ktha from a table using the intake air temperature THA as a parameter as shown in FIG. FIG.
4, the correction coefficient K is obtained when the intake air temperature THA = 20 ° C.
tha = 1, the correction coefficient Ktha increases as the intake air temperature THA decreases. That is, as the intake air temperature THA decreases, the intake pipe 10 is cooled, and the degree of temperature rise of the intake air decreases, so that the density of the intake air increases. Therefore,
The correction coefficient Ktha is increased in order to increase the fuel injection amount as the outside air temperature THA decreases. However, when the correction coefficient Kspd becomes 1 and the correction based on the traveling wind is not required, the correction coefficient Ktha is set to 1 and the process proceeds to step 408.

Then, in step 408, the ECU 30 calculates a final intake air temperature correction coefficient FTHA by the following equation (5). FTHA = FTHAo × Kthw × Ktp × Kctp × Kspd × Ktha (5) Next, in step 109 shown in FIG. 2, the ECU 30 calculates the final injection time TAU by the above-described equation (2). Thereafter, a drive signal corresponding to the final injection time TAU is output to the injector 5 by the ECU 30, the valve opening time of the injector 5 is controlled, and a predetermined amount of fuel is injected.

However, in the present embodiment, the basic injection time TP is calculated based on a map set when the intake air temperature THA is 20 ° C. and there is no running wind (SPD = 0).

In this embodiment, step 400 in FIG. 12 corresponds to the integrating means, and step 401 corresponds to the warm-up determining means. Steps 402, 403, 40
Reference numeral 8 corresponds to a load state correction unit. Step 4
05 corresponds to the traveling wind determination means, and steps 406 to 40
8 corresponds to the traveling wind correction means.

As described above, also in this embodiment, the following effects can be obtained in addition to the same effects as those of the above-described embodiment. (1) The fuel injection amount supplied to the engine 1 is corrected according to not only the strength of the traveling wind during traveling of the vehicle but also the intake air temperature THA substantially matching the outside air temperature. Specifically, when the intake air temperature THA (outside air temperature) is low, the amount of fuel supplied to the engine 1 is corrected to an increased amount. As a result, a desired amount of fuel can be supplied to the engine 1.

The present embodiment can be embodied with the following modifications. In the above embodiment, the basic injection time TP is used as a parameter corresponding to the load state of the engine 1. However, the present invention is not limited to this. For example, the intake air amount obtained from the intake pipe pressure PM and the engine speed NE May be used. In this case, in step 106 of FIG.
The correction coefficient Ktp may be obtained from a table in which the intake air amount obtained from M and the engine speed NE is used as a parameter. In addition, the integrated value of the intake air amount may be obtained in step 200 of FIG. 8, and the correction coefficient Kctp may be obtained in step 203 from a table using the integrated value of the intake air amount as a parameter.

Further, the throttle opening detected by the throttle sensor 24 may be used as a parameter corresponding to the load state of the engine. Also, the amount injected from the injector 5 (basic injection time TP × final intake air temperature correction coefficient FTHA)
X increase / decrease amount correction coefficient α) may be used as a parameter corresponding to the load state of the engine. In this case, the heat generation amount of the engine 1 may be estimated based on the integrated value of the amount injected from the injector 5 to correct the fuel injection amount.

In the third and fourth embodiments, the correction based on the traveling wind is performed even after the completion of the warm-up. However, the correction may be performed at least during the warm-up. In particular,
If it is determined in step 300 of FIG. 10 that the warm-up is completed, the ECU 30 determines in step 302 that the correction coefficient Ktp
= 1, Knv = 1, and the routine proceeds to step 306. Alternatively, when it is determined in step 401 of FIG. 12 that the warm-up is completed, the ECU 30 sets the correction coefficients Ktp = 1, Kctp = 1, Kspd = 1, and Ktha = 1 in step 404, and proceeds to step 408. Also in this case, the intake air temperature correction during the warm-up of the engine 1 is accurately performed.

In step 109 of FIG. 2, the final intake air temperature correction coefficient FTHA may be calculated by using the following equation (6) instead of the above-described equation (1). FTHA = FTHAo × (1+ (Kthw−1) × Ktp) (6) However, when the water temperature THW becomes 80 ° C. (Kthw = 1), the warm-up completion determination in step 105 is performed, and step 1 is performed.
At 07, the correction coefficient Ktp = 1.

In this way, the fuel injection amount is corrected based on the basic injection time TP during the warm-up after the low temperature start, and the desired fuel injection amount can be supplied to the engine 1.

In the first embodiment, the predetermined time T for judging complete warm-up in step 105 in FIG. 2 depends on the intake air temperature THA as shown in FIG. To change. For example, a time Tx from when the engine 1 is started until the water temperature THW reaches 80 ° C. is measured, and the predetermined time T is changed based on the time Tx. In other words, if the time Tx is short, it is determined that the warm-up progress is fast and the time to complete the warm-up is short, and the predetermined time T is shortened. Conversely, if the time Tx is long, it is determined that the warm-up progress is slow and the time to complete the warm-up is long, and the predetermined time T is shortened. Even in this case, the warm-up state can be accurately determined.

In the above embodiment, the water temperature sensor 21 for detecting the temperature of the cooling water of the engine 1 is used as the temperature detection means for the intake pipe, but the temperature sensor for detecting the oil temperature or the cylinder block temperature is used. You may.

[0088]

According to the first aspect of the present invention, when the load state changes at the time of low temperature start of the internal combustion engine, the degree of temperature rise of the intake air when passing through the intake pipe changes and the intake air density changes. However, since the injection amount can be corrected in accordance with the change in the intake air density, a desired amount of fuel can be supplied to the internal combustion engine during warm-up.

According to the second aspect of the present invention, since the density correction of the intake air supplied to the engine is accurately performed, a desired amount of fuel can be supplied to the engine during warm-up.

According to the third aspect of the invention, as the basic fuel injection amount per time, that is, the intake air amount increases, the correction amount toward the increasing side is set smaller, and the fuel injection amount is set based on the set correction amount. Is corrected, a desired amount of fuel can be supplied to the engine during warm-up of the engine.

According to the fourth aspect of the present invention, a variation factor at the time of adaptation to the engine is reduced, so that more accurate injection amount control can be performed. According to the fifth aspect of the invention, the fuel injection amount is increased and corrected in accordance with the load integrated value, so that an appropriate injection amount correction can be performed in a period from immediately after the start of the engine to the completion of the warm-up of the intake system. .

According to the sixth aspect of the present invention, since the correction is canceled at an appropriate timing, the correction can be performed without excess or deficiency. According to the seventh aspect of the invention, the fuel injection amount is corrected based on the strength of the traveling wind, so that a desired fuel amount can be supplied to the engine.

According to the present invention, the completion of the warm-up of the engine intake system is determined when a predetermined time has elapsed after the temperature of the engine cooling water has reached the predetermined temperature. , The injection amount correction can be accurately performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an engine system according to a first embodiment.

FIG. 2 is a flowchart for calculating a fuel injection time.

FIG. 3 is a diagram showing a relationship between intake air temperature and an intake air temperature correction coefficient.

FIG. 4 is a diagram showing a relationship between a water temperature and a correction coefficient.

FIG. 5 is a diagram showing a relationship between an intake air temperature and a warm-up determination time.

FIG. 6 is a diagram showing a relationship between a basic fuel injection amount per time and a correction coefficient.

FIG. 7 is a timing chart showing a temperature transition from a low temperature start to a complete warm-up.

FIG. 8 is a flowchart showing a part of a process for calculating a fuel injection time in the second embodiment.

FIG. 9 is a diagram showing a relationship between an integrated value of a basic fuel injection amount per time and a correction coefficient.

FIG. 10 is a flowchart showing a part of a process for calculating a fuel injection time in a third embodiment.

FIG. 11 is a diagram showing a relationship between an N / V ratio and a correction coefficient.

FIG. 12 is a flowchart showing a part of a process for calculating a fuel injection time in a third embodiment.

FIG. 13 is a diagram showing a relationship between a vehicle speed and a correction coefficient.

FIG. 14 is a diagram showing a relationship between an intake air temperature and a correction coefficient.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 10 ... Intake pipe, 21 ...
A water temperature sensor as an intake pipe-corresponding temperature detecting means; 22 an intake air temperature sensor as an intake air temperature detecting means; 30 an ECU;

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 45/00 314 F02D 45/00 314B F-term (Reference) 3G084 BA13 CA01 CA02 CA04 CA09 DA04 DA25 EA07 EA11 EB08 EC03 FA02 FA05 FA07 FA11 FA18 FA20 FA29 FA33 FA36 3G301 KA01 KA05 KA09 KA25 MA13 NA04 NA08 NB02 NC02 NE01 NE06 NE23 PA01Z PA07Z PA10Z PA17Z PD03A PE01Z PE03Z PE08Z PF01Z PF07Z PF16Z

Claims (8)

[Claims] 1. A fuel injection amount control device for detecting an engine speed and an intake pipe pressure and controlling a fuel injection amount in accordance with the detected engine speed and an intake pipe pressure. Warm-up determining means for determining whether the intake system has been warmed up, and when it is determined by the warm-up determining means that the warm-up of the engine intake system has not yet been completed, the load state and the rotational speed of the internal combustion engine are determined. A fuel injection amount control device for an internal combustion engine, comprising: a load state correction unit configured to set a correction amount to the increasing side to be smaller as the load and the rotation speed increase, and to correct the fuel injection amount by the set correction amount. 2. An intake air temperature detecting means for detecting an intake air temperature in an upstream portion of an intake pipe, an intake pipe corresponding temperature detecting means for detecting a temperature corresponding to a temperature of the intake pipe, and a fuel injection amount as the intake air temperature decreases. 2. The fuel injection amount control device for an internal combustion engine according to claim 1, further comprising: intake correction means for correcting the fuel injection amount to the increase side as the intake pipe corresponding temperature is lower. 3. A basic fuel injection amount corresponding to an engine speed and an intake pipe pressure is set as a parameter corresponding to a load state, and the correction means sets a correction amount to an increasing side as the basic fuel injection amount per time increases. The fuel injection amount control device for an internal combustion engine according to claim 1 or 2, wherein the fuel injection amount is corrected by setting the correction amount to a small value. 4. The fuel injection amount control device for an internal combustion engine according to claim 3, wherein the basic fuel injection amount is an injection amount set based on a warm-up completion state of the engine intake system. 5. An accumulator for calculating an integrated value of a load from the start of the engine, wherein the load state correcting means corrects a fuel injection amount in accordance with the calculated integrated value of the load. The fuel injection amount control device for an internal combustion engine according to claim 4. 6. An integrated means for calculating an integrated value of a load from the start of the engine, wherein the load state correcting means increases and corrects a fuel injection amount in accordance with the calculated integrated value of the load, and The determination means is
5. The system according to claim 1, wherein when the calculated load integrated value reaches a predetermined value, it is determined that the warm-up of the engine intake system has been completed.
The fuel injection amount control device for an internal combustion engine according to any one of claims 1 to 3. 7. A traveling wind determining means applied to an internal combustion engine mounted on a vehicle, for determining a traveling wind intensity when the vehicle is traveling,
The fuel injection amount of the internal combustion engine according to any one of claims 1 to 6, further comprising a traveling wind correction unit that corrects a fuel injection amount based on a traveling wind intensity determined by the traveling wind determination unit. Control device. 8. The intake pipe-corresponding temperature detecting means is a water temperature sensor for detecting a temperature of engine cooling water, and the warm-up judging means is provided when a predetermined time has elapsed since the temperature of the cooling water reached a predetermined temperature. 3. The fuel injection amount control device for an internal combustion engine according to claim 2, wherein it is determined that the warm-up of the engine intake system has been completed.