JP2000356152A - Start timing control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve startability of internal combustion engine even when a voltage of a battery is reduced and even when a carbon is jammed into an intake/exhaust valve. SOLUTION: When a number of rotation of a real cranking enesm is low (step 103, No) or a real cranking time ecstart is short (step 104, No), control moves to the normal control of a throttle valve to terminate a processing (step 108). When the real cranking enesm is high (step 103, Yes) or the real cranking time ecstart is long (step 104, Yes), this control device determines that an engine can not be normally operated due to compression failure by a carbon jamming into an intake/exhaust valve, and carries out a valve opening control of the throttle valve by a throttle actuator (step 105). Accordingly, startability of the engine can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine start control device for improving the startability of an internal combustion engine.

[0002]

2. Description of the Related Art An apparatus of this type is disclosed in, for example,
Japanese Patent Application Publication No. 240080/1990. In the device described in this publication, it is difficult to start the internal combustion engine when the temperature is extremely low, and the cranking time until the start is increased. Therefore, when the cranking time continues for a predetermined time, the intake throttle valve is opened. Thus, the amount of intake air is increased, so that plug fogging is avoided and the startability of the internal combustion engine is improved.

[0003]

The startability of the internal combustion engine is deteriorated not only by the temperature of the internal combustion engine but also by other factors. For example, when the cranking rotation speed is reduced due to a decrease in the voltage of the battery, or when carbon is trapped between the intake and exhaust valves and the valve seat, the airtightness of the combustion chamber in the compression process is reduced, and poor compression occurs. As a result, the startability of the internal combustion engine is reduced.

For this reason, merely increasing the amount of intake air when the cranking time is prolonged as in the apparatus described in the above-mentioned publication appropriately addresses various factors that deteriorate the startability of the internal combustion engine. I couldn't. For example, when the cranking rotation speed decreases due to a decrease in battery voltage, the cranking time increases. At this time, if the intake air amount is increased, the compression pressure of the combustion chamber is increased, and the atomization of the fuel is deteriorated. As a result, the startability of the internal combustion engine is further deteriorated. Conversely, in the case where carbon is trapped between the intake / exhaust valve and the valve seat and compression failure occurs, the startability of the internal combustion engine cannot be improved unless the intake air amount is sufficiently increased.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems, and improves the startability of an internal combustion engine even when the battery voltage drops or when carbon is trapped in an intake / exhaust valve. It is an object of the present invention to provide a start-up control device for an internal combustion engine that can perform the control.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention comprises an electronic control actuator for adjusting an intake air amount of an internal combustion engine, and the internal combustion engine is controlled by controlling the electronic control actuator. A start-up control device for an internal combustion engine that adjusts an intake air amount at start-up of the internal combustion engine; a rotational speed detecting means for detecting a cranking rotational speed at the time of starting the internal combustion engine; and a cranking detected by the rotational speed detecting means. And control means for controlling the electronic control actuator so that the intake air amount is increased when the rotation speed is higher than a predetermined rotation speed threshold value.

According to the present invention, when the cranking speed becomes high, the electronic control actuator is controlled to increase the intake air amount. For example, the airtightness of the combustion chamber in the compression process is reduced by the engagement of carbon in the intake and exhaust valves, and when poor compression occurs, the startability of the internal combustion engine is reduced. In this case, since the cranking speed increases due to a decrease in the compression pressure of the combustion chamber, if the intake air amount is increased by controlling the electronic control actuator at this time, poor compression is eliminated, and the startability of the internal combustion engine is improved. improves. In addition, when the cranking rotation speed decreases due to a decrease in the voltage of the battery, the intake air amount does not increase, so that the startability of the internal combustion engine is not further deteriorated as in the related art.

In one embodiment, there is provided a clocking means for clocking a cranking time until the internal combustion engine is started, and the control means controls the cranking time measured by the clocking means for a first time which is a predetermined time. If it is longer than the threshold value, the electronic control actuator is controlled so that the intake air amount is increased.

That is, when it is difficult to start the internal combustion engine, the cranking time becomes long. Therefore, the intake air amount is increased only when the cranking time becomes longer than the first time threshold value. As a result, the intake air amount does not increase unnecessarily.

In one embodiment, the rotation speed threshold is:
The temperature is set based on the temperature of the internal combustion engine or the voltage of a battery that supplies electric power for performing cranking at the time of starting the internal combustion engine.

The cranking speed changes depending on the temperature of the internal combustion engine and the voltage of the battery. For this reason, the rotation speed threshold value is also changed in accordance with the temperature of the internal combustion engine and the voltage of the battery. Going exactly.

In one embodiment, the rotation speed threshold is:
When the start time of the internal combustion engine is shorter than a predetermined second time threshold, the start time is updated based on the rotation speed of the internal combustion engine.

[0013] Since the cranking speed becomes lower or higher due to variations in the power characteristics of the internal combustion engine or changes over time, the rotation speed of the internal combustion engine when the internal combustion engine starts normally is regarded as the power characteristics. The rotation speed threshold value is updated according to the rotation speed, and the threshold value is matched with the power characteristics. As a result, it is accurately determined whether or not the cranking rotation speed is higher than the rotation speed threshold value, that is, the compression failure determination.

In one embodiment, when controlling the electronic control actuator such that the intake air amount is increased, the control means controls the intake control in accordance with the cranking rotation speed detected by the rotation speed detection means. The amount of increase in air volume is adjusted.

When the intake air amount is increased, the compression pressure of the combustion chamber of the internal combustion engine increases, and the load on the internal combustion engine increases. For this reason, the amount of increase in the amount of intake air is adjusted according to the cranking rotational speed, thereby appropriately increasing the amount of intake air.

In one embodiment, when controlling the electronic control actuator such that the intake air amount is increased, the control means adjusts the increase amount of the intake air amount according to the temperature of the internal combustion engine. ing.

When the amount of intake air increases and the compression pressure of the combustion chamber of the internal combustion engine increases or the temperature of the internal combustion engine decreases, atomization of fuel in the combustion chamber deteriorates. For this reason, the amount of increase in the amount of intake air is adjusted according to the temperature of the internal combustion engine, thereby preventing deterioration of the atomization of the fuel in the combustion chamber.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of the starting control device of the present invention. In FIG. 1, an internal combustion engine (hereinafter referred to as an engine) 1 is provided with a throttle valve 4. The opening degree of the throttle valve 4 is adjusted by a throttle actuator 5 as an electronic control actuator, whereby the amount of air taken into the engine 1 is adjusted.

A piston 9 which reciprocates in the vertical direction in the figure is disposed in a cylinder 8 constituting a cylinder of the engine 1, and the piston 9 is connected to a crankshaft 11 via a connecting rod 10. Above the piston 9, a combustion chamber 13 defined by the cylinder 8 and the cylinder head 12 is formed. The combustion chamber 13 communicates with the intake pipe 2 and the exhaust pipe 3 via the intake valve 14 and the exhaust valve 15.

An intake port 17 of the engine 1 is provided with an electromagnetically driven injector 18, and fuel (gasoline) is supplied to the injector 18 from a fuel tank (not shown). In this case, the air supplied from the upstream of the intake pipe 2 and the injected fuel supplied by the injector 18 are mixed at the intake port 17, and the air-fuel mixture is mixed in the combustion chamber 13 (cylinder) with the opening operation of the intake valve 14. 8). The air-fuel mixture that has flowed into the combustion chamber 13 is compressed therein, and is ignited by an ignition spark emitted from a spark plug 19 to explode. Engine 1
Will get rotational torque by this explosion. The gas after combustion is discharged to the exhaust pipe 3 via the exhaust valve 15 as exhaust gas.

The cylinder 8 (water jacket)
Is provided with a water temperature sensor 21 for detecting the temperature of the cooling water. Further, the crankshaft 11 outputs a pulse signal at every 720 ° CA (crank angle) according to the rotation state, and outputs a pulse signal at every constant crank angle (for example, 30 ° CA). A rotation speed sensor 23 is provided.

Further, an air flow meter 24 for detecting the amount of intake air is provided upstream of the intake pipe 2. Accelerator pedal 2 depressed by driver
5 is provided with an accelerator sensor 26 for detecting the amount of depression of the accelerator pedal 25. A transmission (not shown) is provided with a shift sensor 28 for detecting a shift position of the transmission.

On the other hand, the ECU 30 has a well-known CPU, RO
It is mainly configured by a microcomputer including an M, a RAM, an I / O circuit, and the like. The ECU 30 includes a water temperature sensor 21, a reference position sensor 22, a rotation speed sensor 2,
3. Input detection signals from the air flow meter 24, the accelerator sensor 26, and the shift sensor 28, and detect the engine water temperature, crank angle, engine speed, intake air amount, accelerator opening, and shift position based on these various detection signals. I do.

The ECU 30 calculates a fuel injection amount (or fuel injection time), an ignition timing, a target throttle opening, and the like based on various detection outputs from the sensor group.
The fuel injection by the injector 18, the ignition by the spark plug 19, and the opening of the throttle valve 4 by the throttle actuator 5 are controlled.

In such a configuration, when the ignition key 27 is operated to turn on the starter motor, a power supply path from the battery 31 to the starter motor (not shown) is formed, and the starter motor is turned on. Electric power is supplied, the starter motor operates, the crankshaft 11 rotates, the piston 9 reciprocates, the air-fuel mixture flows into the combustion chamber 13, an ignition spark is emitted from a spark plug 19, and the engine 1 starts operating. Operate.

As described above, when the cranking speed decreases due to the voltage drop of the battery 31, and when the carbon gets into between the valves 14, 15 and the valve seat, the airtightness of the combustion chamber 13 in the compression step is reduced. When the compression failure occurs, and when the water temperature of the engine 1 extremely decreases, the startability of the engine 1 decreases.
For this reason, in the control device of the present embodiment, when starting the engine 1, the processes of the flowcharts shown in FIGS. 2, 3, and 4 are performed, thereby preventing the startability of the engine 1 from deteriorating.

First, the outline of the processing by the control device of the present embodiment will be described with reference to the flowchart of FIG. The process of the flowchart in FIG. 2 is repeated, for example, every 8 msec.

The ECU 30 determines whether or not the starter motor is turned on and the starter motor is operating (step 101). When the starter motor is turned on (step 101, Yes), the engine 1 is in the start mode. This is determined based on whether the engine speed is equal to or lower than a predetermined speed (step 102).

When the engine 1 is in the start mode (step 102, Yes), the ECU 30 sets the engine rotational speed detected by the rotational speed sensor 23 as the cranking rotational speed enesm and the actual cranking rotational speed enesm and the first rotational speed enesm. The rotation speed threshold enesmgx is compared (step 103). Here, the first rotation speed threshold enesmgx is determined in steps 201 and 202 described later.
Of the cooling water THW and the battery 3
It is determined based on one voltage BaT.

Then, the ECU 30 determines that the actual cranking rotational speed enesm is equal to the first rotational speed threshold enesmg.
If it is higher than x (Step 103, Yes), carbon is trapped between each of the valves 14, 15 and the valve seat, and the airtightness of the combustion chamber 13 in the compression stroke is reduced. The actual cranking time ecstartx is compared with the first time threshold ecstartx (step 104). Note that the cranking time ecstart is controlled by the starter motor and the crankshaft 1.
The ECU 30 counts a cranking time ecstart by counting a period in which the starter motor is on by a counter, where 1 is a rotating period. Also, the first time threshold value ecstartx
Is obtained on the basis of the first rotation speed threshold enesmgx and the temperature THW of the cooling water, similarly to the processing of step 203 described later.

Thereafter, the ECU 30 determines that the actual cranking time ecstart is equal to the first time threshold ecstar.
If it is longer than tx (Step 104, Yes), it is considered that the engine 1 has not started to operate normally, and the throttle actuator 5 controls the opening of the throttle valve 4 (Step 105).
To improve the startability of the vehicle.

If the starter motor is off (step 101, No) or the engine 1 is not in the start mode (step 102, No),
Alternatively, the starter motor is on and the engine 1
Is in the start mode, the cranking speed enes
If m is low (step 103, No) or the cranking time ecstart is short (step 104, N
o), it is determined whether the engine 1 is in the previous start mode (step 106).

When the engine 1 is not in the start mode (step 102, No) and is in the previous start mode (step 106, Yes), that is, when the engine 1 has shifted from the start mode to the post-start mode,
The learning of the first rotational speed threshold enesmgx is performed (step 107), and thereafter, the routine shifts to the normal control of the throttle valve 4 (step 108), and the processing in FIG.

That is, in the process of FIG. 2, it is determined whether or not compression failure has occurred using the cranking rotation speed enesm and whether or not the engine 1 has started normally using the cranking time ecstart. Judge,
When the operation is not started normally due to poor compression, the opening control of the throttle valve 4 is performed to improve the startability of the engine 1.

FIG. 3 is a flowchart showing the processing of step 107 in FIG. 2 in more detail.

As described above, when the engine 1 has shifted from the start mode to the post-start mode, first in the flowchart of FIG.
First rotation speed threshold enesm in AM as shown in FIG.
Reference is made to the data table 51 in which gx is learned and stored. In the data table 51, a plurality of learning areas j corresponding to the coolant temperature THW and the voltage BaT of the battery 31 are set, and the first rotation speed threshold enesmgx is learned and stored for each learning area j. are doing.
When the battery 31 is removed, for example, the first rotation speed threshold enesm learned and stored for each learning region j.
gx, that is, learning value enesmgxj for each learning region j
Is set to an initial value. Here, the initial value of each learning region j is an average value set in advance on the assumption that the engine 1 has an average power characteristic.

The ECU 30 calculates the coolant temperature THW detected by the coolant temperature sensor 21 and the voltage detector 3
2 corresponds to the learning area j corresponding to the voltage BaT of the battery 31 detected by the
(Step 201).

Next, the ECU 30 sets the selected learning area j
Is read out. When the detected coolant temperature THW indicates the median of the selected learning region j and the median of the median values of the learning regions j adjacent to the selected learning region j, the respective coolant temperatures THW are adjacent. The learning value enesmgxj in the learning area j is read. Similarly, when the detected voltage BaT of the battery 31 indicates the median value of each voltage BaT of the median value of the selected learning region j and the median value of the learning region j adjacent to the selected learning region j, The learning value enes in this adjacent learning area j
Read mgxj.

The learning values e thus read out
Using nesmgxj, the detected coolant temperature TH
A first rotation speed threshold enesmgx corresponding to W and the detected voltage BaT of the battery 31 is obtained (step 202). Here, each learning value ene is obtained by interpolation.
One first rotational speed threshold enesmg from smgxj
Seeking x. However, in step 202, 1
When only the learning values enesmgxj in one learning region j are read, it is not necessary to use the interpolation method, and the learning value enesmgxj in the learning region j is equal to the first rotation speed threshold e.
nesmgx.

Further, the ECU 30 uses the first rotation speed threshold enesmgx and the detected coolant temperature THW to set a function f ₃ (enesmgx, TH
A first time threshold value ecstartx is obtained based on W) (step 203).

The ECU 30 determines the cranking rotational speed enesm in the start mode and the first rotational speed threshold enesmg.
1.3 times the value of x, and the actual cranking time ecstart, ie, the starting time e of the engine 1
cstart is compared with a value 0.9 times the second time threshold ecstartx (second time threshold) (step 204).

Then, the cranking speed enesm in the start mode is larger than 1.3 times the first speed threshold enesmgx, and the engine 1 is started normally and the start time ecstart is set to the first time. If the time threshold value ecstartx is smaller than 0.9 times (second time threshold value) (step 204, Yes),
The power characteristics of Engine 1 are out of average,
Since the crankshaft 11 is easy to rotate and the friction of the engine 1 is small, the process proceeds to step 205 for updating the learning value enesmgx to match the power characteristic of the engine 1.

In step 205, the ECU 30
A preset value Ks is added to the learning value enesmgxj in the selected learning region j, and the learning value enesmgxj in the selected learning region j is updated.

Further, the cranking rotation speed enesm in the start mode is equal to the first rotation speed threshold enesmgx equal to 1.
If the value is not more than three times, or the actual start time ecstart is not more than 0.9 times the second time threshold value ecstartx (second time threshold value) (step 204, N
o) The ECU 30 compares the cranking rotational speed enesm in the start mode with a value 0.7 times the first rotational speed threshold enesmgx, and also calculates the actual start time ecs.
start and the first time threshold ecstartx of 0.9
Compare the doubled value (second time threshold) (Step 20)
6).

The cranking speed enes in the start mode
m is smaller than 0.7 times the first rotation speed threshold enesmgx, and the engine 1 is started normally and the start time ecstart is set to the first time threshold ecsta.
If it is smaller than 0.9 times rtx (second time threshold) (Yes in step 206), the power characteristic of the engine 1 is out of the average, and the crankshaft 11
Is difficult to rotate, and the friction of the engine 1 is large.
The process proceeds to step 207 for updating the learned value enesmgxj to match the power characteristic of the engine 1.

In step 207, the ECU 30
A preset value Ks is subtracted from the learning value enesmgxj in the selected learning area j, and the selected learning area j
Is updated.

As described above, in the process of the flowchart of FIG. 3 (the process of step 107 in FIG. 2), the cranking speed enesm in the starting mode is compared with the first speed threshold enesmgx, and the starting mode is compared. The cranking speed enesm is the first speed threshold enesmgx
If it is too high or too low, the first rotational speed threshold value en
Learning value enes of each learning area j for deriving esmgx
mgxj is updated so that each learning value enesmgxj matches the power characteristic of the engine 1. For example, Engine 1
Is small, the learning value enesmgxj of each learning region j is gradually increased each time the engine 1 is started, so that the first rotation speed threshold enesmgx increases and the actual cranking rotation speed enesmx increases. , That is, the first rotational speed threshold enesmgx matches the power characteristic of the engine 1. Each learning value en
When esmgxj becomes sufficiently large, the cranking rotation speed enesm in the start mode becomes the first rotation speed threshold value en.
Since it is determined that the value is less than or equal to 1.3 times esmgx (No at Step 204), the learning value enesm of each learning area j is determined.
gxj does not become unnecessarily large. Further, when the friction of the engine 1 is large, the learning value enesmgxj of each learning region j is gradually reduced every time the engine 1 is started.
Becomes smaller and approaches the actual cranking rotation speed enesm. When each learning value enesmgxj becomes sufficiently small, the cranking rotation speed enesm in the start mode is determined to be equal to or more than 0.7 times the first rotation speed threshold enesmgx (step 206, No). The learning value enesmgxj of the area j does not become unnecessarily small.

Also, the first rotational speed threshold enesmgx
And the detected cooling water temperature THW is used to determine the first time threshold value ecstartx, so that the first time threshold value ecstartx is also updated with the update of the learning value enesmgxj of each learning region j. become.

Thus, the learning value enesm of each learning area j is obtained.
If gxj is matched to the power characteristics of the engine 1, the first rotation speed threshold enesmgx matched to the power characteristics
And a first time threshold ecstartx. As a result, in steps 103 and 104 in FIG. 1, it is accurately determined whether or not the engine 1 has been started normally based on the first rotation speed threshold enesmgx and the first time threshold ecstartx. Becomes possible.

FIG. 4 is a flowchart showing the processing of step 105 in FIG. 2 in more detail.

As described above, the actual cranking rotation speed enesm is high and the actual cranking time ecst
art is long (each step 104, Yes, 106, Y
es) If it is determined that the engine 1 has not started to operate normally due to poor compression, control for opening the throttle valve 4 by the throttle actuator 5 is started to improve the startability of the engine 1 (step 105).

The flowchart of FIG. 4 (step 1 in FIG. 2)
At 05), the ECU 30 first determines whether or not the previous control was in the normal mode, that is, the state in which the valve opening control of the throttle valve 4 has not been started (step 30).
1). Since the valve opening control of the throttle valve 4 has not been started at first (step 301, Yes), the ECU 30
Initializes the valve opening control elapsed time ccarbon to 0 and stores the actual cranking rotation speed enesm as the valve opening control immediately preceding rotation speed enesmb (step 30).
2).

Then, the ECU 30 calculates the coolant temperature TH.
Using W, a preset function f _Four(THW) based
The carbon correction opening dcarbon is obtained (step 3
03). Further, the ECU 30 determines the base opening degree dg and the water temperature compensation.
The normal opening dsta and the carbon correction opening dcarbon
And add the sum to the target opening TA of the throttle valve 4.
tg (step 304), and set the throttle
By controlling the drive of the tutor 5, the throttle
Adjust the opening of the valve 4 to the target throttle opening TAtg
You.

The graph of FIG. 6 shows the characteristic of the target throttle opening TAtg at the time of starting with respect to the coolant temperature THW. The target throttle opening TAtg is the base opening d
g, water temperature correction opening dsta and carbon correction opening dca
This is the sum of rbon.

The base opening dg is a predetermined constant value.

The water temperature correction opening dsta is a value that varies according to the water temperature THW of the cooling water as described above, and is obtained based on a preset function. As the water temperature THW is lower, the water temperature correction opening dsta is increased, and accordingly, the target throttle opening TAtg is increased, the intake air amount is increased, and the startability is improved.

The carbon correction opening degree dcarbon is a value that varies according to the coolant temperature THW, and is obtained based on a preset function. The higher the water temperature THW,
The carbon correction opening dcarbon is increased, and accordingly, the target throttle opening TAtg is increased, the intake air amount is increased, and the startability is improved. In other words, when carbon is trapped between the valves 14 and 15 and the valve seat, the airtightness of the combustion chamber 13 in the compression process is reduced, and when poor compression occurs, the startability deteriorates. In addition, the target throttle opening TAtg is increased, and the intake air amount is increased to compensate for a decrease in the compression pressure in the combustion chamber 13, thereby improving the startability.

Unless the process of the flowchart of FIG. 4 (the process of step 105 in FIG. 2) is performed, the control is shifted to the normal control of the throttle valve 4 (step 108 in FIG. 2), and the base opening dg and the water temperature correction opening are set. The sum of dsta is obtained as a target throttle opening TAtg, and the opening of the throttle valve 4 is adjusted to the target throttle opening TAtg.

Thereafter, the processing of the flowchart of FIG. 2 is repeated, and when returning to step 105, the ECU 30 has already started the opening control of the throttle valve 4, so that
It is determined that the previous control is not in the normal mode (step 30).
1, No), the valve opening control elapsed time ccarbon is incremented (step 305), and the valve opening control elapsed time ccar
It is confirmed that the bonus has not reached 1 second (step 306, No), and the process returns to the step 101 in FIG.

Here, when the engine 1 operates and exits the start mode while repeating the processing of the flowchart of FIG. 2, the routine shifts to the normal control of the throttle valve 4 (step 1).
08), and the processing in FIG. 2 ends.

If the start mode is continued, steps 301, 305 and 306 are repeated, and the valve opening control elapsed time ccarbon reaches 1 second (step 30).
6, Yes). Then, the ECU 30 initializes the valve opening control elapsed time ccarbon to 0 (step 30).
7), a function f ₅ (enesmb, THW) set in advance using the rotation speed enesmb just before the valve opening control and the coolant temperature THW stored in step 302.
The second rotation speed threshold enesmv is obtained based on Further, the ECU 30 obtains the third rotation speed threshold enesml based on the function f ₆ (THW) set in advance using the coolant temperature THW (step 308).

The graph of FIG. 7 shows the rotation speed en immediately before the valve opening control.
It shows the characteristics of the second rotation speed threshold enesmv with respect to esmb, and the respective characteristic curves are drawn for each water temperature THW. The slope of each characteristic curve is obtained by comparing the second rotation speed threshold enes with the rotation speed enesmb just before the valve opening control.
The ratio of mv is shown. In the calculation for obtaining the second rotational speed threshold enesmv in step 308, a characteristic curve corresponding to the detected coolant temperature THW is selected, and the rotational speed enes immediately before the valve opening control is selected based on the selected characteristic curve.
This is equivalent to obtaining the second rotation speed threshold enesmv for mb. When the characteristic curve corresponding to the detected coolant temperature THW is located in the middle of each characteristic curve, the characteristic curve at the intermediate position is obtained by interpolation, and the second rotation speed threshold enesmv is calculated based on this characteristic curve. Ask.

Here, if the degree of compression failure due to the biting of carbon is large, the carbon correction opening dcarb
Although the intake air amount has already been increased by adding on, the compression pressure in the combustion chamber 13 does not increase significantly. For this reason, the load on the engine 1 does not increase, the actual cranking rotational speed enes hardly decreases, and the actual cranking rotational speed enesm is reduced to the second rotational speed threshold enesm.
greatly exceeds v. Therefore, if the actual cranking rotation speed enesm greatly exceeds the second rotation speed threshold enesmv, it can be understood that the degree of compression failure due to the biting of carbon is large.

The graph of FIG. 8 shows the characteristics of the third rotation speed threshold enesml with respect to the coolant temperature THW. The third rotation speed threshold enesml indicates the minimum cranking rotation speed required to start the engine 1, and changes according to the water temperature THW. Step 3
The calculation for obtaining the third rotation speed threshold enesml in step 08 is performed based on the characteristic curve of FIG.
This is equivalent to obtaining the rotational speed threshold enesml.

Here, when the degree of compression failure due to the entrapment of carbon is small, the compression pressure in the combustion chamber 13 increases due to the already increased intake air amount, and the load on the engine 1 increases. Actual cranking speed en
esm becomes lower than the third rotation speed threshold enesml. At this time, atomization of the fuel in the combustion chamber 13 deteriorates, and it becomes extremely difficult to start the engine 1. Therefore, if the actual cranking rotation speed enesm is lower than the third rotation speed threshold enesml, the atomization of the fuel in the combustion chamber 13 is degraded.

In step 308, the second rotation speed threshold enesmv and the third rotation speed threshold enes are obtained.
After obtaining ml, the ECU 30 compares the actual cranking rotational speed enesm with a value 1.3 times the second rotational speed threshold enesmv (step 309). The actual cranking speed enesm is equal to the second speed threshold en
If it is larger than 1.3 times esmv (step 309, Yes), that is, as described above, the actual cranking speed enesm is equal to the second speed threshold enes.
It can be seen that when the value is much higher than mv, the degree of compression failure due to the engagement of carbon is large. For this reason, the ECU 30
Calculates the corrected opening based on a function f ₇ (THW) set in advance using the coolant temperature THW, adds the corrected opening to the carbon corrected opening dcarbon, and calculates the carbon corrected opening dcarbon. Update (step 31
0). Then, the ECU 30 updates the target opening TAtg of the throttle valve 4 (step 304) and opens the opening of the throttle valve 4 by the corrected opening. As a result,
The intake air amount is further increased, and the reduction in the compression pressure in the combustion chamber 13 is further compensated for, and the startability is improved.

If the actual cranking rotational speed enesm is equal to or less than 1.3 times the second rotational speed threshold enesmv (No in step 309), the ECU 30 determines that the actual cranking rotational speed enesm is equal to the third rotational speed enesm. Rotational speed threshold e
Nesml is compared (step 311). The actual cranking speed enesm is equal to the third speed threshold ene.
If it is lower than sml (step 311, Yes),
As described above, the degree of compression failure due to the entrapment of carbon is small, and the atomization of the fuel in the combustion chamber 13 is deteriorated. Therefore, the ECU 30 calculates the function f ₇ (THW)
Is calculated based on the following formula, and the corrected opening is subtracted from the carbon corrected opening dcarbon to obtain a carbon corrected opening dc.
Arbon is updated (step 312). And E
The CU 30 updates the target opening TAtg of the throttle valve 4 (step 304), and closes the opening of the throttle valve 4 by the correction opening. As a result, the intake air amount is reduced, the fuel in the combustion chamber 13 is atomized well, and the startability of the engine 1 is improved.

As described above, in the process of the flowchart of FIG. 4 (the process of step 105 of FIG. 2), the target opening TAtg of the throttle valve 4 is changed to the carbon correction opening dcar.
bon, the intake air amount is once increased, and thereafter, after the valve opening control elapsed time ccarbon reaches 1 second, the actual cranking rotation speed enesm, the second rotation speed threshold enesmv, and the The degree of change in the actual cranking rotational speed enesm is determined by comparing the three rotational speed thresholds enesml, and the actual cranking rotational speed enesm is determined by the second rotational speed threshold en.
If the value is larger than 1.3 times the value of esmv, the degree of compression failure due to the engagement of carbon is large, and the carbon correction opening dcarbon is increased, and the target opening TAtg of the throttle valve 4 is increased. 4, the opening degree is further increased, the intake air amount is further increased, and the decrease in the compression pressure in the combustion chamber 13 is further compensated to improve the startability. Also, the actual cranking speed enes
When m becomes lower than the third rotation speed threshold enesml, the degree of compression failure due to the engagement of carbon is small, and the carbon correction opening dcarbon is reduced.
The target opening TAtg of the throttle valve 4 is reduced, the opening of the throttle valve 4 is reduced, the amount of intake air is reduced, and the fuel in the combustion chamber 13 is atomized satisfactorily.
Has improved the starting performance.

As described above, in this embodiment, each valve 14,
When carbon is trapped in 15 and compression failure occurs and the cranking speed increases, the intake air amount is increased to eliminate compression failure and improve the startability of the internal combustion engine. In addition, when the battery voltage decreases and the cranking speed decreases, the intake air amount does not increase, so that the startability of the internal combustion engine is not further deteriorated as in the related art.

Also, since the intake air amount is readjusted in accordance with the change in the cranking speed after the intake air amount is increased, the intake air amount can be further increased according to the degree of compression failure. The amount of intake air can be reduced.

Further, since each learning value in the ROM is matched with the power characteristic of the engine 1 and each learning value corresponding to the coolant temperature THW and the voltage BaT of the battery 31 is read from the ROM, these learning values are read. Based on the value, it can be accurately determined whether or not the operation of the engine 1 has started normally.

The present invention is not limited to the above embodiment, but can be variously modified. For example, it is preferable to change the contents of each function according to the power characteristics of the engine. Further, each threshold value may be appropriately increased or decreased.

[0074]

As described above, according to the present invention, when the cranking rotational speed becomes high, the electronic control actuator is controlled to increase the amount of intake air. For example, the airtightness of the combustion chamber in the compression process is reduced by the engagement of carbon in the intake and exhaust valves, and when poor compression occurs, the startability of the internal combustion engine is reduced. In this case, since the cranking speed increases due to a decrease in the compression pressure of the combustion chamber, if the intake air amount is increased by controlling the electronic control actuator at this time, poor compression is eliminated, and the startability of the internal combustion engine is improved. improves. In addition, when the cranking rotation speed decreases due to a decrease in the voltage of the battery, the intake air amount does not increase, so that the startability of the internal combustion engine is not further deteriorated as in the related art.

According to one embodiment, when the cranking time measured by the timer is longer than the first time threshold, the controller increases the intake air amount.
In other words, when it is difficult to start the internal combustion engine, the cranking time becomes longer. Therefore, the intake air amount is increased only when the cranking time becomes longer than the first time threshold value. As a result, the intake air amount does not increase unnecessarily.

According to one embodiment, the rotational speed threshold is:
It is set based on the temperature of the internal combustion engine or the voltage of the battery. The cranking speed changes depending on the temperature of the internal combustion engine and the voltage of the battery. For this reason, the rotation speed threshold value is also changed in accordance with the temperature of the internal combustion engine and the voltage of the battery. Going exactly.

According to one embodiment, the rotational speed threshold is:
If the start time of the internal combustion engine is shorter than the second time threshold, the update is performed based on the rotation speed of the internal combustion engine. Since the cranking speed becomes lower or higher due to variations in the power characteristics of the internal combustion engine or changes over time, the rotation speed of the internal combustion engine when the internal combustion engine starts normally is regarded as the power characteristics, and the rotation speed of this internal combustion engine is , The rotational speed threshold value is updated, and this threshold value is matched with the power characteristics. As a result, it is accurately determined whether or not the cranking rotation speed is higher than the rotation speed threshold value, that is, the compression failure determination.

According to one embodiment, the amount of increase of the intake air amount is adjusted according to the detected cranking speed. When the intake air amount is increased, the compression pressure of the combustion chamber of the internal combustion engine increases, and the load on the internal combustion engine increases. For this reason, the amount of increase in the amount of intake air is adjusted according to the cranking rotational speed, thereby appropriately increasing the amount of intake air.

According to one embodiment, the amount of increase in the amount of intake air is adjusted according to the temperature of the internal combustion engine. When the amount of intake air increases and the compression pressure of the combustion chamber of the internal combustion engine increases or the temperature of the internal combustion engine decreases, atomization of fuel in the combustion chamber deteriorates. For this reason, the amount of increase in the amount of intake air is adjusted according to the temperature of the internal combustion engine, thereby preventing deterioration of the atomization of the fuel in the combustion chamber.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a start-time control device according to the present invention.

FIG. 2 is a flowchart showing an outline of processing in the control device of FIG. 1;

FIG. 3 is a flowchart showing the processing of step 107 in FIG. 2 in more detail;

FIG. 4 is a flowchart showing the processing of step 105 in FIG. 2 in more detail;

FIG. 5 is a diagram showing a data table in the control device of FIG. 1;

FIG. 6 is a graph showing a characteristic of a target throttle opening TAtg at the time of starting with respect to a coolant temperature THW.

FIG. 7 is a graph showing the relationship between the rotation speed enesmb immediately before the valve opening control and the second rotation speed.
It is a graph which shows the characteristic of rotation speed threshold enesmv.

FIG. 8 is a graph showing characteristics of a third rotation speed threshold enesml with respect to a cooling water temperature THW.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine (engine) 2 Intake pipe 3 Exhaust pipe 4 Throttle valve 5 Throttle actuator 8 Cylinder 9 Piston 10 Connecting rod 11 Crankshaft 12 Cylinder head 13 Combustion chamber 14 Intake valve 15 Exhaust valve 17 Intake port 18 Injector 19 Spark plug 21 Water temperature sensor 22 Reference Position Sensor 23 Speed Sensor 24 Air Flow Meter 25 Accelerator Pedal 26 Accelerator Sensor 27 Ignition Key 28 Shift Sensor 30 ECU 31 Battery 32 Voltage Detector

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Naoto Kushi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G065 CA00 DA04 EA01 FA09 FA13 GA05 GA09 GA10 GA31 GA46 KA36 3G301 JA00 KA01 LA03 LC03 MA11 NA08 NB06 NC02 NC06 ND32 NE01 NE23 PA01Z PE01Z PE03Z PE04Z PE08Z PF03Z PF07Z PF16Z PG01Z

Claims (6)

[Claims] 1. An internal combustion engine start-up control device that includes an electronic control actuator that adjusts an intake air amount of an internal combustion engine, and that controls the electronic control actuator to adjust an intake air amount when the internal combustion engine is started. A rotational speed detecting means for detecting a cranking rotational speed at the time of starting the internal combustion engine, and if the cranking rotational speed detected by the rotational speed detecting device is higher than a predetermined rotational speed threshold value, A control unit for controlling the electronic control actuator so that the intake air amount is increased. 2. A time counting means for counting a cranking time until the internal combustion engine is started, wherein the control means includes a first time threshold value determined by the time counting means. 2. The start-up control device for an internal combustion engine according to claim 1, wherein the control unit controls the electronic control actuator so as to increase the intake air amount when the length is longer than the predetermined length. 3. The method according to claim 1, wherein the rotation speed threshold value is set based on a temperature of the internal combustion engine or a voltage of a battery that supplies electric power for performing cranking at the time of starting the internal combustion engine. A start-up control device for an internal combustion engine according to the above. 4. The engine according to claim 1, wherein the rotation speed threshold is updated based on the rotation speed of the internal combustion engine when a start time of the internal combustion engine is shorter than a predetermined second time threshold. 4. The control device for starting an internal combustion engine according to any one of claims 1 to 3. 5. The control means, when controlling the electronic control actuator so as to increase the intake air amount, adjusts the intake air amount according to a cranking rotation speed detected by the rotation speed detection means. 5. The starting control device for an internal combustion engine according to claim 1, wherein the increasing amount is adjusted. 6. The control unit according to claim 1, wherein when controlling the electronic control actuator such that the intake air amount is increased, the control unit adjusts the increase amount of the intake air amount according to a temperature of the internal combustion engine. 5. The start-up control device for an internal combustion engine according to any one of claims 1 to 4.