JP7108496B2 - INTERNAL COMBUSTION ENGINE START CONTROL METHOD AND INTERNAL COMBUSTION ENGINE DRIVE CONTROL APPARATUS - Google Patents

Description

TECHNICAL FIELD The present invention relates to a drive control device for an internal combustion engine, and more particularly to a device intended to improve the reliability and stability of low-temperature starting when a crank sensor fails.

In an internal combustion engine having a plurality of cylinders, a crank sensor signal corresponding to the rotation of the crank wheel obtained by a crank sensor and a cam sensor signal corresponding to the rotation of the cam wheel obtained by a cam sensor are used to determine the relative value of these two signals. As is well known, it is well known that the cylinders are discriminated based on the relationship, the appearance pattern, and the like, and the drive control of the internal combustion engine is performed.

In such an internal combustion engine, from the viewpoint of ensuring the safety and reliability of the device, a configuration that can execute emergency control in the event of an abnormal control state caused by a part failure or the like should be adopted. There are many.
For example, if the crank sensor used to acquire the crank sensor signal fails, an increment signal corresponding to one tooth of the crank sensor signal can be artificially generated based on the cam sensor signal detected by the cam sensor. A number of technologies and the like that enable driving have been proposed and put into practical use (see, for example, Patent Document 1).

JP-A-5-240102

However, when starting the internal combustion engine in a low-temperature environment, the cam sensor signal may not be obtained normally, so the increment signal, which is a pseudo signal of the crank signal based on the cam sensor signal, may not be updated normally. In the worst case, the engine cannot be started due to misfiring.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned actual situation, and an internal combustion engine start control method and an internal combustion engine that can ensure reliable engine start even when a cam sensor signal cannot be properly acquired at low temperature start. A drive control device is provided.

In order to achieve the object of the present invention, an internal combustion engine start control method according to the present invention comprises:
An internal combustion engine start control method for assisting starting of an internal combustion engine when a crank sensor fails, comprising:
A cam sensor signal period, which is a period of a cam sensor signal detected by a cam sensor, is measured, and a TDC signal period, which is a period of a TDC signal which is a top dead center detection signal of a piston arranged in a cylinder of the internal combustion engine, is measured. death,
calculating a cycle of an increment signal as a pseudo signal of the crank sensor signal detected by the crank sensor by a predetermined arithmetic expression using the cam sensor signal cycle and the TDC signal cycle;
By providing the rotational speed of the internal combustion engine calculated based on the cycle of the increment signal for start control of the internal combustion engine, the start of the internal combustion engine is ensured.
Further, in order to achieve the object of the present invention, an internal combustion engine drive control device according to the present invention includes:
An internal combustion engine drive control device comprising an electronic control unit capable of controlling the operation of the internal combustion engine based on a crank sensor signal and a cam sensor signal,
The electronic control unit is
A cam sensor signal period, which is a period of a cam sensor signal detected by a cam sensor, is measured, and a TDC signal period, which is a period of a TDC signal which is a top dead center detection signal of a piston arranged in a cylinder of the internal combustion engine, is measured. death,
calculating a cycle of an increment signal as a pseudo signal of the crank sensor signal detected by the crank sensor by a predetermined arithmetic expression using the cam sensor signal cycle and the TDC signal cycle;
Starting control of the internal combustion engine can be executed using the rotational speed of the internal combustion engine calculated based on the period of the increment signal.

According to the present invention, even if the cam sensor signal period is not measured for some reason, the increment signal is updated according to the TDC signal period. It is possible to ensure more reliable injection timing than in the prior art at the time of low-temperature start-up when the injection timing deviation is likely to occur, and it is possible to provide a vehicle with high reliability and stability. is.

1 is a configuration diagram showing a configuration example of an internal combustion engine drive control device according to an embodiment of the present invention; FIG. 4 is a subroutine flowchart showing the overall procedure of internal combustion engine start control processing according to the embodiment of the present invention; 4 is a subroutine flowchart showing a specific procedure of low temperature engine start backup processing executed in internal combustion engine start control processing in the embodiment of the present invention; 4 is a subroutine flow chart showing a specific procedure of a process for detecting the lowest point of battery voltage, which is executed in the low temperature engine start backup process in the embodiment of the present invention; 5(A) is a timing chart showing the generation timing of an increment signal generated by the low-temperature engine start backup process according to the embodiment of the present invention, FIG. 5(A) being a timing chart showing the generation timing of a cam sensor signal; FIG. 5(B); 5C is a timing chart showing the generation timing of the TDC signal, FIG. 5C is a timing chart showing the generation timing of the increment signal, and FIG. 5D is a timing chart showing the change in the engine speed acquired by the increment signal. . FIG. 4 is a schematic diagram schematically showing an example of change in battery voltage during execution of minimum point detection processing for detecting the minimum voltage point executed in low-temperature engine start backup processing according to the embodiment of the present invention; FIG. 4 is a schematic diagram schematically showing an example of change in engine speed when internal combustion engine start control processing is executed in the embodiment of the present invention; FIG. 5 is a schematic diagram schematically showing an example of change in engine speed when the engine speed is obtained based on an increment signal generated using a conventional technique;

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. FIG.
The members, arrangement, etc., described below do not limit the present invention, and can be modified in various ways within the spirit and scope of the present invention.
First, an example configuration of an internal combustion engine drive control system according to an embodiment of the present invention will be described with reference to FIG.
An internal combustion engine drive control system according to the embodiment of the present invention is configured with an electronic control unit 100 mounted on an automobile, a cam sensor 1 and a crank sensor 2 as main components.

The electronic control unit 100 is configured to be able to execute various control processes necessary for driving an automobile, such as fuel injection control, and is itself installed in a conventional automobile capable of electronic control. It has basically the same configuration as the one.
The electronic control unit 100 includes, for example, a microcomputer (not shown) having a well-known configuration, volatile memory elements such as RAM and ROM, and non-volatile memory elements (not shown). (not shown)) and an input/output interface circuit (not shown) as a main component.

In the electronic control unit 100, along with detection signals from the cam sensor 1 and the detection signals from the crank sensor 2, engine operation control such as engine speed, vehicle speed, cooling water temperature of the engine (not shown) detected by sensors (not shown), etc. Various detection signals and the like necessary for are input to the , and are provided for fuel injection control processing, internal combustion engine start control processing, etc., which will be described later.

In the embodiment of the present invention, the engine (not shown) as an internal combustion engine has a four-cylinder configuration, and the cam wheel 3 rotates once (720 degrees) for two rotations (720 degrees) of the crank wheel 4 described below. 360 degrees).
During two revolutions of the crank wheel 4, one engine cycle of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke is executed in each of the four cylinders (not shown).

A cam wheel 3 attached to a camshaft (not shown) has four cam teeth 3a to 3d radially outwardly provided at 90-degree intervals on its periphery, and one cam tooth 3a, as in the conventional art. It has a reference cam tooth 3e provided at a predetermined angle.

The cam sensor 1 is provided at an appropriate position where the four cam teeth 3a to 3d and the reference cam tooth 3e pass nearby. The cam sensor 1 outputs a cam sensor signal, which is a pulse signal, corresponding to each of the four cam teeth 3a to 3d and the reference cam tooth 3e passing near the cam sensor 1, as in the conventional art. .

A crank wheel 4 attached to a crank shaft (not shown) is provided with a plurality of crank teeth 4a extending radially outward at predetermined angular intervals on its periphery, as in the conventional art. For example, it has a configuration in which two consecutive crank teeth are missing.
The crank sensor 2 is provided at an appropriate position where the crank tooth 4a passes by, and outputs a crank signal, which is a pulse signal, corresponding to the passage of the crank tooth 4a.

The engine (not shown) is started by the starter 5 as in the conventional art.
That is, by inserting the ignition key 6 into the keyhole and turning it to the engine start position, power supply voltage from the battery 8 is supplied to the starter 5 via the relay 7 . As a result, the starter 5 starts rotating, and the engine is started.

Next, the internal combustion engine start control process according to the embodiment of the present invention executed by the electronic control unit 100 will be described with reference to FIGS. 2 to 7. FIG.
First, referring to FIG. 2, the general procedure of the internal combustion engine starting control process according to the embodiment of the present invention will be described.
When the processing by the electronic control unit 100 is started, cranking is started and the engine is started (see step S100 in FIG. 2), and then it is determined whether the crank sensor signal is normal (see FIG. 2). 2, step S200).

If it is determined that the crank sensor signal is normal (YES), the process proceeds to step S300. If it is determined that the crank sensor signal is not normal (NO), the process proceeds to step S500. will proceed to
Whether or not the crank sensor signal is normal can be determined, for example, by determining whether or not the integrated value of the crank sensor signal acquired during a certain period of time exceeds a predetermined threshold value.

That is, in this case, if the integrated value of the crank sensor signal for a predetermined period of time is below a predetermined threshold value, it is determined that the crank sensor signal is faulty, that is, the crank sensor 2 is faulty. be able to.
The determination method itself may be one that has been used conventionally, and does not need to be limited to a specific method.

In step S300, in response to the fact that the crank sensor signal is normal, acquisition of the engine speed based on the crank sensor signal is performed by executing normal processing similar to the conventional one.
Next, it is determined whether or not the engine has been started normally (see step S400 in FIG. 2). The process returns to the main routine (not shown).
On the other hand, if it is determined in step S400 that the engine has not been started normally (in the case of NO), the process returns to step S200 to repeat the series of processes.

In step S500, it is determined whether or not it is a low temperature start.
The judgment as to whether or not it corresponds to the low temperature start depends on the outside air temperature, the engine cooling water temperature, the capacity of the battery 8, the specifications of the engine, etc., and is not limited to specific judgment conditions.
Therefore, it is preferable to determine the specific conditions for judging whether or not the low-temperature start is applicable, based on the test results and simulation results, taking into consideration the above-described judgment factors. It should be noted that the outside air temperature, which is one of the factors for judging low-temperature starting, is approximately 0°C.

In step S500, if it is determined to be a low temperature start (YES), the process proceeds to step S600, and if it is determined not to be a low temperature start (NO), the process proceeds to step S700. will proceed to

First, in step S700, a conventional engine start backup process (normal engine start backup process) is executed.
That is, this normal engine start backup process is a control that allows the engine to start when the crank sensor signal is in a failed state and the engine is not started at a low temperature.

Specifically, for example, there is a method of starting the engine using a pseudo-generated crank sensor signal based on the cam sensor signal. This normal engine start backup process does not need to be limited to a specific method, and it is optional to use any of various conventionally known methods.

On the other hand, in step S600, a low temperature engine start backup process is executed as the internal combustion engine start control process in the embodiment of the present invention.
This low-temperature engine start backup process is a control that enables the engine to start more reliably than before when the crank sensor signal fails and in the case of a low-temperature start (details will be described later). ).
After executing the process of step S600 or step S700, the process proceeds to the process of step S400 described above.

Next, the specific procedure of the low-temperature engine start backup process will be described with reference to the subroutine flow charts shown in FIGS. 3 and 4, the timing chart shown in FIG. 5, and the characteristic diagram shown in FIG. do.
First, the low temperature engine start backup process in the embodiment of the present invention will be generally described.

The low-temperature engine start backup process according to the embodiment of the present invention is characterized in that an increment signal, which is a pseudo signal instead of a crank signal, is generated based on the period of the cam sensor signal and the period of the TDC signal. is.

Here, the TDC signal is a top dead center detection signal of a piston arranged in a cylinder (not shown). In the embodiment of the present invention, the TDC signal is detected based on variations in battery voltage (details will be described later).

A specific description will be given below with reference to the subroutine flow chart shown in FIG.
When the processing by the electronic control unit 100 is started, input signal discrimination is first performed (see step S610 in FIG. 3).
That is, it is determined whether either the cam sensor signal or the TDC signal has been input.

If it is determined in step S610 that the cam sensor signal has been input, the process proceeds to step S620. If it is determined that the TDC signal has been input, the process proceeds to step S640.

In step S620, the time between cam sensor signals, ie, period measurement is performed.
In the embodiment of the present invention, the cam wheel 3 has four cam teeth 3a-3d and one reference cam tooth 3e as described above.
When the four cam teeth 3a to 3d and the reference cam tooth 3e pass near the cam sensor 1, the cam sensor 1 generates one pulse signal as shown in FIG. is output as a crank sensor signal.

In FIG. 5A, for example, the cam sensor signal labeled 5Fa corresponds to the passage of the cam tooth 3a, and the cam sensor signal labeled 5Fe immediately after that corresponds to the passage of the reference cam tooth 3e. Yes. The cam sensor signal labeled 5Fb corresponds to the passage of the cam tooth 3b, the cam sensor signal labeled 5Fc corresponds to the cam tooth 3c, and the cam sensor signal labeled 5Fd corresponds to the cam tooth 3d. there is

The period measurement of the cam sensor signal in step S620 measures the time from the detection of one cam sensor signal to the detection of the next cam sensor signal.
A well-known method can be used for such period measurement of the input signal. Specifically, it is preferable to use a counter that measures time by software.

Next, an increment signal as a pseudo signal of the crank sensor signal is calculated based on the cam sensor signal period measured as described above (see step S630 in FIG. 3). Such an increment signal is a signal corresponding to one tooth of the crank sensor signal.
For convenience of explanation, the increment signal calculated based on the latest cam sensor signal period will be referred to as a "sensor increment signal".

Calculation of the increment signal will be specifically described below.
First, in the embodiment of the present invention, as described above, the cam wheel 3 rotates once (360 degrees) while the crank wheel 4 rotates twice (720 degrees).
Since the cam teeth 3a to 3d of the cam wheel 3 in the embodiment of the present invention are provided at intervals of 90 degrees, the time of one cycle of the cam sensor signal measured in step S620 is equivalent to 90 degrees rotation of the cam wheel 3. correspond to time.

In other words, a 90 degree rotation of the cam wheel 3 corresponds to a 180 degree rotation of the crank wheel 4 . Therefore, if the time of one cycle of the cam sensor signal measured in step S620 is Tcas(n), and the number of crank teeth (the number of crank signals) of the crank wheel 4 between 180 degrees is Nsim, the conventional increment signal S( n) was calculated as S(n)=Tcas(n)/Nsim.

In contrast, in the embodiment of the present invention, the increment signal calculated immediately after one period of the cam sensor signal is measured is the measurement result of the n-th cam sensor signal period, and Tcas(n) is calculated by the following arithmetic expression (first expression).

Scas(n)={a*Tcas(n)+b*Tbat(n-1)}/Nsim Equation 1

Here, Scas(n) is the period of the increment signal, and after this period is calculated, the increment signal is generated successively in this period.
In the above formula, Tbat(n-1) is measured before the cam sensor signal period Tcas(n) is measured, as shown in FIGS. 5(A) and 5(B). It is the value of one period of the most recent TDC signal.
Also, Nsim is the number of crank teeth between 180 degrees of the crank wheel 4 as described above.

Further, a and b are weighting coefficients and are determined so that a+b=1.
The increment signal is inherently updated each time a new cycle of the cam sensor signal is measured.
However, if a new period of the cam sensor signal cannot be measured due to a cold start, the increment signal is conventionally maintained based on the most recently measured period of the cam sensor signal. rice field.

In contrast, in the embodiment of the present invention, as described above, the increment signal is obtained using the cam sensor signal period and the most recent TDC signal period. , the increment signal is updated by the amount corresponding to the weighting according to the TDC signal period. Therefore, the frequency of updating the increment signal is higher than in the prior art, and a more accurate increment signal can be obtained.

The weighting coefficients a and b may be of any value, but considering that the cam sensor signal cycle is newer than the TDC signal cycle, the weighting coefficient a is larger than the weighting coefficient b (a >b) is preferred. It is preferable to select specific values for the weighting coefficients a and b based on test results and simulation results in consideration of specific vehicle specifications and the like.

On the other hand, when the TDC signal is input, the cycle measurement of the TDC signal is executed in step S640.
As described above, the TDC signal is a signal for detecting the top dead center of a piston arranged in a cylinder (not shown), and is detected based on variations in battery voltage.
Here, the method of detecting the TDC signal based on the battery voltage variation will be described with reference to the subroutine flow chart shown in FIG. 4 and the schematic diagram schematically showing an example of battery voltage variation shown in FIG. do.

First, the detection of the TDC signal based on this variation in battery voltage is such that when the piston located in the cylinder is positioned at the top dead center, the electrical load rises, and the battery voltage is at its highest compared to before and after that. This is the one that takes advantage of the lowering.
A specific description will be given below.
First, as a premise, the battery voltage is measured at predetermined time intervals by the electronic control unit 100, and the measured voltages are successively and temporarily stored in an appropriate storage area within the electronic control unit 100. shall be

When the electronic control unit 100 starts the TDC signal detection process, the two battery voltages measured most recently are compared in magnitude (see step S680 in FIG. 4).
In step S680, the battery voltage Vbatt(t-1) is the latest measured voltage, and the battery voltage Vbatt(t-2) is the latest measured voltage before the latest measured voltage.

In step S680, it is determined whether the latest measured voltage Vbatt(t-1) is smaller than the latest measured voltage Vbatt(t-2).
This step S680 is repeated until it is determined (YES) that the latest measured voltage Vbatt(t-1) is smaller than the latest measured voltage Vbatt(t-2).

If it is determined in step S680 that the latest measured voltage Vbatt(t-1) is smaller than the latest measured voltage Vbatt(t-2), the process proceeds to step S682.
In step S682, a new measured voltage Vbatt(t) is read, and the previous measured voltage Vbatt(t-1) is compared with the measured voltage Vbatt(t) as the latest measured voltage.
That is, it is determined whether or not the new measured voltage Vbatt(t) is higher than the latest measured voltage Vbatt(t-1) {Vbatt(t)>Vbatt(t-1)}.

If it is determined in step S682 that the new measured voltage is greater than the most recent measured voltage, that is, Vbatt(t)>Vbatt(t-1) (if YES), the most recent measured voltage Vbatt(t- 1) is determined to be the minimum voltage in the fluctuation of the battery voltage accompanying the vertical movement of the piston.

On the other hand, if it is determined in step S682 that Vbatt(t) is not greater than Vbatt(t-1) (NO), the process returns to step S680 to repeat the series of processes.
FIG. 6 schematically shows an example of changes in battery voltage in this measurement example, and the notation of each battery voltage in the figure is the same as the notation of the battery voltage in FIG.

As a result, the time point (t-1) at which the minimum voltage Vbatt(t-1) is measured is determined as the top dead center (TDC position) (see step S684 in FIG. 4), and the TDC signal is generated inside the electronic control unit 100. It is generated, and a series of processing is terminated.

Here, let us return to the description of the processing procedure of FIG. 3 again.
In step S640, period measurement of the TDC signal generated as described above is performed.
Since this period measurement is basically the same as the period measurement of the cam sensor signal described in step S620, detailed description will be omitted here.

Next, based on the measured TDC signal period, an increment signal as a pseudo signal of the crank sensor signal is calculated (see step S650 in FIG. 3).
Here, the increment signal calculated based on the cycle of the TDC signal is hereinafter referred to as a "voltage increment signal" for convenience of explanation in order to distinguish it from the sensor increment signal.

Assuming that the TDC signal period measured for the n-th time is Tbat(n), the voltage increment signal Sbat(n) in the embodiment of the present invention is calculated by the following arithmetic expression (second expression). ing.

Sbat(n)={c×Tcas(n)+d×Tbat(n)}/Nsim Equation 2

In the above formula, Tcas(n) is the cam sensor signal period measured immediately before the measurement of the TDC signal period Tbat(n) (see FIGS. 5A and 5B).

Also, Nsim is the number of crank teeth between 180 degrees of the crank wheel 4 as described above.
In addition, c and d are weighting coefficients determined so that c+d=1.

Since the voltage increment signal emphasizes the most recently measured TDC signal period, unlike the weighting factors a and b in the sensor increment signal Scas(n), the weighting factor d is larger than the weighting factor c (d>c ) is preferable.
It is preferable to select specific values for the weighting coefficients c and d based on test results and simulation results in consideration of specific vehicle specifications and the like.

When the sensor increment signal or voltage increment signal is calculated as described above, the increment signal (sensor increment signal or voltage increment signal) used until recently is discarded, and the newly calculated sensor increment signal is discarded. signal or voltage increment signal, and the increment signal is updated (see step S660 in FIG. 3).
Next, the engine speed is calculated based on the updated increment signal, and a new engine speed is obtained (see step S670 in FIG. 3).

Thus, in the embodiment of the present invention, the increment signal is generated using the cam sensor signal period and the TDC signal period, so not only is it updated when a new cam sensor signal period is measured, It is also updated when a new TDC signal period is measured.

Therefore, the engine speed calculated based on the increment signal is updated every time either a new cam sensor signal period or a new TDC signal period is measured ( (See FIGS. 5A to 5D).
Therefore, even when the crank sensor 2 fails and the engine is started at a low temperature, it is possible to support the start control by ensuring a highly reliable and stable engine start, unlike the conventional art.

FIG. 7 shows a characteristic line showing a simulation result of changes in engine speed with respect to updating the increment signal in the embodiment of the present invention, and FIG. 8 shows changes in engine speed with respect to updating the conventional increment signal. are shown, respectively, and the update of the increment signal in the embodiment of the present invention will be described in comparison with the conventional example with reference to the two figures.

7 and 8, the horizontal axis indicates the passage of time, and the vertical axis indicates the engine speed.
Further, in the two figures, the solid line is a characteristic line showing changes in the engine speed.
In FIG. 7, the point marked with an X on the characteristic line representing the change in the engine speed represented by the solid line is the point in time when the sensor increment signal is acquired, that is, the increment signal based on the first equation above. represents the time when was updated. In addition, the points marked with circles on the same characteristic line represent the points in time when the voltage increment signal is obtained, that is, the points in time when the increment signal is updated based on the second equation.

On the other hand, in FIG. 8, the cross-marked portions on the characteristic line representing the change in the engine speed represented by the solid line indicate the points in time when the increment signal is updated by the conventional method.

Comparing FIG. 8 with FIG. 7, it can be seen that in the case of the present invention, after the increment signal is updated a plurality of times, the engine speed steadily increases steadily.
In contrast, in the conventional case, after the increment signal is updated a plurality of times, the engine speed fluctuates up and down, and it can be understood that it is difficult to ensure a smooth increase in the engine speed.

It can be applied to vehicles where it is desired to ensure reliable engine starting at low temperature starting in the event of cam sensor failure.

1... cam sensor 2-crank sensor 100... electronic control unit

Claims (8)

An internal combustion engine start control method for assisting starting of an internal combustion engine when a crank sensor fails, comprising:
A cam sensor signal period, which is a period of a cam sensor signal detected by a cam sensor, is measured, and a TDC signal period, which is a period of a TDC signal which is a top dead center detection signal of a piston arranged in a cylinder of the internal combustion engine, is measured. death,
calculating a cycle of an increment signal as a pseudo signal of the crank sensor signal detected by the crank sensor by a predetermined arithmetic expression using the cam sensor signal cycle and the TDC signal cycle;
A start control method for an internal combustion engine, wherein the number of revolutions of the internal combustion engine calculated based on the cycle of the increment signal is used for start control of the internal combustion engine to ensure start of the internal combustion engine. The predetermined arithmetic expression is
A first equation used when the latest value Tcas(n) of the cam sensor signal period is measured, and a second equation used when the latest value Tbat(n) of the TDC signal period is measured. Consists of
The first equation is defined as Scas(n)={a*Tcas(n)+b*Tbat(n-1)}/Nsim, where Scas(n) is the period of the increment signal to be calculated. In the first equation, Tbat(n-1) is the most recent TDC signal period measured immediately before Tcas(n) is measured, and a and b are weighted with a+b=1 relationship. The coefficient Nsim is the number of crank signals detected by the crank sensor during one period of the cam sensor signal,
The second equation is defined as Sbat(n)={c×Tcas(n)+d×Tbat(n)}/Nsim, where Sbat(n) is the period of the increment signal to be calculated. where Tcas(n) is the most recent cam sensor signal period measured immediately before Tbat(n) is measured, and c and d are weighting coefficients having a relationship of c+d=1, 2. A method according to claim 1, wherein said Nsim is the number of crank signals detected by said crank sensor during one period of said cam sensor signal. 3. The method of claim 2, wherein the weighting coefficients a and b satisfy a>b, and the weighting coefficients c and d satisfy d>c. 4. The internal combustion engine start control method according to claim 1, wherein said TDC signal is detected based on variations in battery voltage. An internal combustion engine drive control device comprising an electronic control unit capable of controlling the operation of the internal combustion engine based on a crank sensor signal and a cam sensor signal,
The electronic control unit is
A cam sensor signal period, which is a period of a cam sensor signal detected by a cam sensor, is measured, and a TDC signal period, which is a period of a TDC signal which is a top dead center detection signal of a piston arranged in a cylinder of the internal combustion engine, is measured. death,
calculating a cycle of an increment signal as a pseudo signal of the crank sensor signal detected by the crank sensor by a predetermined arithmetic expression using the cam sensor signal cycle and the TDC signal cycle;
A drive control apparatus for an internal combustion engine, wherein starting control of the internal combustion engine can be executed using the rotational speed of the internal combustion engine calculated based on the period of the increment signal. The electronic control unit is
As the predetermined arithmetic expression, the first expression is used when the latest value Tcas(n) of the cam sensor signal period is measured, and the first expression is used when the latest value Tbat(n) of the TDC signal period is measured. Using the second equation, calculate the period of each increment signal,
The first equation is defined as Scas(n)={a*Tcas(n)+b*Tbat(n-1)}/Nsim, where Scas(n) is the period of the increment signal to be calculated. In the first equation, Tbat(n-1) is the most recent TDC signal period measured immediately before Tcas(n) is measured, and a and b are weighted with a+b=1 relationship. The coefficient Nsim is the number of crank signals detected by the crank sensor during one period of the cam sensor signal,
The second equation is defined as Sbat(n)={c×Tcas(n)+d×Tbat(n)}/Nsim, where Sbat(n) is the period of the increment signal to be calculated. where Tcas(n) is the most recent cam sensor signal period measured immediately before measurement of Tbat(n), and c and d are weighting coefficients having a relationship of c+d=1. 6. The internal combustion engine drive control apparatus according to claim 5, wherein said Nsim is the number of crank signals detected by said crank sensor during one period of said cam sensor signal. 7. The internal combustion engine drive control system according to claim 6, wherein said weighting coefficients a and b satisfy a>b, and said weighting coefficients c and d satisfy d>c. 8. The internal combustion engine start control method according to claim 5, wherein said electronic control unit is configured to detect said TDC signal based on variations in battery voltage.

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