JP2000110638A - Vehicular engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the discharge of an unburnt component even when an engine is in a no-load condition and even before the completion of engine warming up without excessively restricting the performance of the engine, and to prevent the abrasion of an engine sliding part caused by the overspeed of the engine, in a vehicular engine control device. SOLUTION: Normally, a control means 12a controls an engine speed not to exceed the maximum engine speed by restricting fuel supply to an engine 20 based on engine speed information, and when the engine 20 is in a no-load condition, the control means 12a controls the engine speed within a first limit engine speed lower than the maximum engine speed based on information from no-load condition judging means 11a, warming up condition judging means 11b and engine speed detecting means, and also when the engine 20 is in the no-load condition and before the completion of the engine 20 warming up, the control means 12a controls the engine speed within a second limit engine speed lower than the first limit engine speed. Therefore, the excessive increase of the engine speed is suppressed according to the warming up condition of the engine 20 when the engine 20 is no-load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle engine control device capable of limiting an engine speed (rotation speed), and more particularly to a vehicle engine control device suitable for use in a gasoline direct injection engine for an automobile. .

[0002]

2. Description of the Related Art Conventionally, for the purpose of preventing an overspeed of a vehicle engine, when the engine speed (rotation speed) exceeds a predetermined limit speed, a fuel supply is stopped (fuel cut). Engine control devices (hereinafter sometimes simply referred to as engine control devices) have been developed. In such an engine control device, generally, the limit rotational speed is set to a constant value regardless of the load state of the engine.

[0003]

However, the above-mentioned conventional vehicle engine control apparatus has the following problems. That is, the shift position of the automatic transmission (A / T) is in the N range or the P range, or the shift position of the manual transmission (M / M) is different from the state in which the engine and the drive system of the vehicle are connected (load state). In a state where the shift position of T) is the neutral position or the drive system of the vehicle is separated from the engine (no load state), the load on the engine is remarkably limited to internal friction of the engine and the transmission. small. Therefore, when the accelerator pedal is depressed deeply in a no-load (no-load) state (at the time of N / L (no-load) racing), there is almost no load on the engine, so the intake air amount is small, and the fuel is increased according to the intake air amount. The injection amount is also small.

In such a state, since the amount of intake air is small, the variation in measurement of the amount of intake air by the sensor is large.
Since the fuel injection amount is small, the variation in the fuel injection amount by the injector also becomes large. In addition, since the engine load is small, the engine speed is easily increased and decreased, and the engine speed is easily fluctuated rapidly. . When the engine speed fluctuates rapidly in this way, the fuel injection amount necessary for one cylinder to explode at one time is accurately calculated and injected from the measured intake air amount and engine speed. It is the most difficult state to control the air-fuel ratio as expected due to the nature of the control. Therefore,
Since the air-fuel ratio becomes richer or leaner than expected, the combustion becomes unstable, and the emission of hydrocarbons (HC) and black smoke during combustion increases.

Particularly, in the case of a gasoline direct injection engine in which fuel is directly injected into a cylinder and combustion is performed by spark ignition, a multipoint injection engine in which fuel is injected directly into an intake port to inject fuel into an intake port. Fuel is less likely to evaporate. For this reason,
There is a tendency for hydrocarbon (HC) and black smoke contained in the exhaust gas to increase.

In order to cope with this, it is conceivable to suppress the fluctuation of the engine speed by previously setting a lower limit engine speed at which the fuel cut is performed. Engine load)
This limits the inherent performance of the engine. In order to solve such a problem, a means for determining whether the engine is in a no-load state or a load state is provided, and the limit speed for performing the fuel cut in the no-load state and the load state is separately set, Japanese Patent Application Laid-Open No. Hei 5-44551 discloses an engine control method for setting the speed limit in the no-load state lower than the speed limit in the load state.

However, such an engine control method also has a problem because the engine speed limit in a no-load state is set constant without considering the warm-up state of the engine. That is, as described above, when the engine speed is increased with no load, as in N / L racing, the emission of HC and black smoke during combustion increases.
In particular, since the inside of the cylinder is still low in temperature and the fuel is unlikely to evaporate before the warm-up of the engine is completed, such as at the time of a cold start, the engine speed is reduced under no load at such a cold state. If it is raised, the fuel in the liquid state that does not evaporate cannot complete combustion in the engine,
And the emission of black smoke is even greater. For this reason, in the no-load state before the completion of the warm-up of the engine, it is necessary to further suppress the variation in the air-fuel ratio and perform stable combustion compared to the no-load state after the completion of the warm-up of the engine. .

In the case where the engine speed limit is set to be constant as in the above-described engine control method, the engine speed is set to be limited when the engine speed limit is set based on the no-load state after engine warm-up. For the previous no-load condition, the emission of HC and black smoke during combustion cannot be sufficiently suppressed.
Since the temperature of the lubricating oil is low, sufficient lubrication performance cannot be obtained, causing unnecessary wear of the sliding portion inside the engine. Conversely, if the speed limit is set based on the no-load state before the completion of the warm-up of the engine, the performance of the engine may be excessively limited in the no-load state after the completion of the warm-up of the engine. .

[0009] The present invention has been made in view of such problems, and without excessively restricting the performance of an engine.
Even in the no-load state of the engine and before the completion of warm-up, it is possible to sufficiently suppress the emission of unburned components such as HC and black smoke during combustion, and to eliminate the need for a sliding portion inside the engine due to overspeed of the engine. An object of the present invention is to provide a vehicle engine control device capable of preventing excessive wear.

[0010]

Therefore, in the vehicle engine control apparatus according to the first aspect of the present invention, the control means includes:
By limiting the fuel supply to the engine based on the engine speed information detected by the engine speed detecting means, the engine speed is controlled so as not to exceed a preset maximum speed. The control means includes: determination information from a no-load state determination means for determining whether the engine is in a no-load state; determination information from a warm-up state determination means for determining a warm-up state of the engine; When the engine is in a no-load state, the engine speed is controlled within a first limit rotational speed smaller than the maximum rotational speed based on the detection information from the engine, and when the engine is in a no-load state and the engine is warmed up. Before completing the above, the engine speed is controlled within a second limit speed that is even smaller than the first limit speed.
Therefore, an excessive increase in the engine speed when the engine is not loaded is appropriately suppressed according to the warm-up state of the engine.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a vehicle engine control apparatus according to an embodiment of the present invention. FIG. 1 is a schematic block diagram thereof, FIG. 2 is a flowchart showing a control sequence thereof, and FIG. It is a flowchart which shows the rotation speed limit setting subroutine of a modification.

The vehicle engine control device (EC) of the present invention
U) 10 is mounted on an automobile and includes, as shown in FIG. 1, a no-load state determination unit 11 a, a warm-up state determination unit 11 b, a rotation speed calculation unit 13, and a combustion control unit 12. The part 12 is an injector 21 of the engine 20.
Speed control unit (control means) that outputs a fuel cut command to the engine
12a.

A vehicle speed V from the vehicle speed sensor 1 and a shift position detection signal (hereinafter simply referred to as a position signal) P from the shift position switch 2 are input to the no-load state determination means 11a. The no-load state determining means 11a determines whether the engine is in a no-load state based on the vehicle speed V and the position signal P,
The result is output to the rotation speed control unit 12a.

Here, the shift position switch 2 is
It detects information that can determine whether the engine and the drive system of the vehicle are disconnected or connected. In the case of the present embodiment, an automatic transmission (A / T) is provided between the engine and the drive system, and the shift position switch 2 is configured such that the A / T select lever is set to the neutral position (N
Range) or the parking position (P range), and turns on, and the other position, that is, the drive position (D
Range), reverse position (R range), 3rd speed position (3 range), 2nd speed position (2 range), 1st speed position (1 range)
Is a switch that is turned off when it is at of course,
The shift position switch 2 can be applied to a switch that generates an ON / OFF signal for each range, that is, a switch that generates an ON signal only for a selected range.

Further, the cooling water temperature (hereinafter simply referred to as water temperature) Tw is input to the warm-up state judging means 11b from the water temperature sensor 3, and the warm-up state judging means 11b is provided.
Determines the warm-up state from the water temperature Tw, and outputs the result to the rotation speed control unit 12a. From the crank angle sensor 5, an on / off signal (crank angle signal) θcr is output from the crank angle sensor 5 every time the crank rotates a predetermined crank angle.
Is input, and the rotation speed calculation unit 13 calculates the engine rotation speed based on the on / off signal θcr. The crank angle sensor 5 and the rotation speed calculating unit 13 constitute a rotation speed detecting means.

The combustion control unit 12 includes a determination result from the no-load state determination unit 11a and a warm-up state determination unit 1.
1b, the cam angle signal θca from the cam angle sensor 4, the crank angle signal θcr from the crank angle sensor 5, and the engine speed from the rotation speed calculation unit (rotation speed detection means) 13. The number Ne and the accelerator opening θa from the accelerator position sensor (APS) 6 are input, respectively.

In the combustion control unit 12, the cam angle signal θc detected by the cam angle sensor 4 and the crank angle sensor 5
a, the piston position of each cylinder is recognized based on the crank angle signal θcr, and the fuel injection amount corresponding to the engine rotation speed Ne from the rotation speed calculation unit 13 and the accelerator opening θa from the accelerator position sensor 6, The operation of the injector 21 and the ignition system 22 of the engine 20 is controlled so that the fuel injection timing and the ignition timing come.

However, in the rotation speed control unit 12a, the determination result of the no-load state determination unit 11a and the warm-up state determination unit 11b
And setting the rotational speed limit Nm based on the determination result
The limit engine speed Nm is compared with the actual engine engine speed Ne. When the actual engine engine speed Ne is higher than the engine speed limit Nm, the fuel cut command is sent to the injector 21 by the engine control unit 12a. Is output. The fuel cut command is to prevent a drive signal from being output to a driver (not shown) that drives the injector 21.

The vehicle engine control device according to one embodiment of the present invention is configured as described above.
The engine speed can be controlled by repeating the limit speed setting and the engine speed limit control as shown in FIGS. First, FIG.
In the main routine for setting the rotational speed limit in (a), the position signal P input from the shift position switch 2 is set.
(See FIG. 1), the shift position is in a position (N range, P range) corresponding to a no-load state or a position (D range, R range, 3 range) corresponding to a load state.
It is determined whether the engine is in a no-load state based on whether the engine is in the range, the second range, or the first range (step S10).
That is, if the position signal P is off (the shift position is any of the D range, the R range, the 3 range, the 2 range, and the 1 range), it is determined that the engine is not in a no-load state, and the process proceeds to step S25 to limit the engine. Revolution Nm
Is set to 7000 rpm (maximum rotation speed). on the other hand,
The position signal P is ON, that is, the shift position is N
If it is one of the range and the P range, the process proceeds to step S20, where it is determined again whether the engine is in a no-load state (whether the vehicle is running) based on the level of the vehicle speed V.

In step S20, the vehicle speed V is 10 km /
If it is greater than or equal to h, it is determined that the shift position has entered the N range for a moment during traveling, and the engine is determined to be in the load state, and the engine speed limit Nm is 7000 r.
pm (maximum rotation speed) (step S25).
On the other hand, if the vehicle speed is less than 10 km / h, it is determined that the vehicle is not running (the engine is not loaded), and the process proceeds to step S30.

In step S30, it is determined whether or not the engine has been completely warmed up based on the water temperature Tw. If the water temperature Tw is equal to or lower than 20 ° C., it is determined that the warm-up of the engine has not been completed, and the engine speed limit Nm is set to 2800 rpm (second
(The number of revolutions) (step S32). Also,
If the water temperature Tw is higher than 20 ° C. and lower than 80 ° C., it is either during warm-up or the warm-up is completed, and the process proceeds to step S40 to determine again the warm-up of the engine. If the water temperature Tw is equal to or higher than 80 ° C., it is determined that the warm-up of the engine has been completed, and the process proceeds to step S45, where the speed limit Nm is set to 3200 rpm (first speed limit).

In step S40, it is determined whether the engine has been completely warmed up based on the elapsed time t after the water temperature Tw has reached 20 ° C. If the elapsed time t is 3 minutes or less, the engine is started. It is determined that the warm-up has not been completed, and the routine proceeds to step S50, where the rotational speed limit Nm is 2800 rpm.
(The second speed limit). On the other hand, if the elapsed time t is 3 minutes or longer, it is determined that the engine has been completely warmed up, and the routine proceeds to step S45, where the limit rotational speed Nm is 3200r.
pm (first limit rotational speed).

Here, the determination in step S40 will be described. Since the coolant temperature Tw changes more slowly than the temperature around the cylinder of the engine which directly receives the heat energy from the combustion, the temperature around the cylinder rises. However, there is a time delay in the rise of the water temperature Tw, and, for example, when the cold start is performed when the outside air temperature is low, the rise in the water temperature Tw may be delayed more than the rise in the temperature around the cylinder. Therefore, the water temperature Tw is a sufficient temperature (here, 80
° C), it can be said that the engine has been warmed up, but the water temperature Tw is lower than this (here, 20 ° C).
(° C. to 80 ° C.), the engine may have already been completely warmed up even if the water temperature Tw is low. Thus, in the present embodiment, if the water temperature Tw is within a certain temperature range (here, 20 ° C. to 80 ° C.) for a predetermined time (here, 3 minutes), it is determined that the warm-up of the engine has been completed. (Step S4
0).

The elapsed time t from when the water temperature Tw reaches 20 ° C. is the water temperature Tw input from the water temperature sensor 3.
(See FIG. 1) The warm-up state determining means 1 is based on the count value of a timer (not shown) which is started when the temperature reaches 20 ° C.
1b. As described above, one cycle of the setting of the number of revolutions is completed, and after a lapse of a predetermined time, the above-described processing is performed again.

In the engine speed limit control routine, as shown in FIG. 2B, in step R10, the above-described speed limit setting main routine (see FIG. 2A).
Rotation speed Nm set by
Of the actual engine speed Ne (see FIG. 1)
Is compared with. If the engine speed Ne is higher than the limit speed Nm, the fuel injection from the injector 21 is stopped to cut the fuel (step R20). On the other hand, if the engine speed Ne is lower than the limit speed Nm, the fuel is cut off. If the cut has been performed, the fuel cut is released and a predetermined fuel injection from injector 21 is performed (step R30).

As described above, one cycle of the engine speed control by the fuel cut is completed, and after a lapse of a predetermined time, the above-described processing is performed again. Thus, according to the vehicle engine control device, when the engine is in the load state,
The engine speed limit for the fuel cut is set stepwise by dividing the case where the engine is in a no-load state and before the completion of warm-up and the case where the engine is in a no-load state and after the completion of warm-up. Therefore, the following effects can be obtained.

Under the load condition of the engine, the rotational speed limit Nm is set to a sufficiently large value so that the inherent performance of the engine is not limited. In the no-load state of the engine, the engine speed limit Nm is set lower than when the engine is in the load state. In particular, even in the no-load state, the fuel is hardly burned before the warm-up of the engine is completed. Sets the limit rotation speed Nm even lower than after the completion of warm-up, and prevents a sudden change in the engine rotation speed Ne to always maintain a stable combustion by setting the air-fuel ratio to an appropriate value. Unburned components such as HC and black smoke in the exhaust gas can be suppressed. Accordingly, the engine speed limit Nm is changed in accordance with the load state of the engine and the warm-up state. Therefore, regardless of the load state of the engine and the warm-up state, the engine performance is not excessively limited and the exhaust gas is not limited. There is an advantage that unburned components therein can be suppressed. In addition, since the water temperature Tw and the rotation speed limit Nm are changed according to the elapsed time t after the water temperature Tw reaches 20 ° C., the engine performance is appropriately limited according to the degree of warm-up. There is also.

In particular, before the engine is warmed up, sufficient lubricating performance cannot be obtained due to the low temperature of the lubricating oil. However, since the engine speed limit Nm is set sufficiently low, the engine overspeeds. There is also an advantage that unnecessary wear of the sliding portion inside the engine due to the above can be prevented. Note that the vehicle engine control device of the present invention is not limited to the above-described embodiment, and can be implemented with various modifications.

For example, in this embodiment, the automatic transmission (A
/ T), but a manual transmission (M / T) may be used. In this case, the shift position switch 2 (FIG. 1)
2) is a switch for turning on the select lever at the neutral position. Step S10 of the main routine for setting the rotational speed limit in FIG. 2A determines whether the shift position is at the neutral position.

The warm-up state of the engine is determined by the intake air temperature Ta.
Steps S32 and S50 of the limit speed setting main routine of FIG. 2A so that the speed limit Nm can be set according to the warm-up state.
May be performed by a limit rotational speed setting subroutine as shown in FIGS. 3A and 3B, respectively.

That is, as shown in FIG. 3A, if the water temperature Tw is not higher than 20 ° C. as determined in step S30 (see FIG. 2A), the process proceeds to step S62.
At 62, the intake air temperature Ta is determined, and the intake air temperature Ta becomes 1
If the temperature is 0 ° C. or lower, the rotational speed limit Nm is set to 2500 rpm (step S70), and if the intake air temperature Ta is 10 ° C. or higher, the rotational speed limit Nm is set to 2800 rpm (step S75).

As shown in FIG. 3B, the water temperature Tw is set to 2 by the judgment in step S40 (see FIG. 2A).
If the elapsed time t after the temperature reaches 0 ° C. is 3 minutes or less, it is determined that the engine is not in the warm-up state, and step S80 is performed.
In step S80, the intake air temperature Ta is determined. If the intake air temperature Ta is equal to or lower than 10 ° C., the limit rotation speed Nm is set to 2600 rpm (step S85), and if the intake air temperature Ta is equal to or higher than 10 ° C. The rotational speed Nm is 2800r
pm (step S90).

In this case, the intake air temperature Ta is input from the intake air temperature sensor to the warm-up state determining means 11b (see FIG. 1).

[0034]

As described above in detail, according to the vehicle engine control apparatus of the present invention, when the engine is in a no-load state without excessively limiting the original performance of the engine,
Unburned components in exhaust gas can be reduced not only after the engine has been warmed up but also before the engine has been warmed up,
Before the warm-up of the engine is completed, there is an advantage that unnecessary wear of the sliding portion inside the engine due to excessive rotation can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a vehicle engine control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a control sequence of the vehicle engine control device according to one embodiment of the present invention, where (a) shows a main routine for setting a rotational speed limit;
(B) shows a rotation speed limit control routine.

FIG. 3 is a flowchart of a limit rotational speed setting subroutine showing a modified example of the control sequence of the vehicle engine control device according to one embodiment of the present invention, where (a) shows a case where the water temperature is 20 ° C. or less; (B) is when the water temperature is 20 ° C. to 8;
Shown is the case within 3 minutes after reaching 0 ° C.

[Explanation of symbols]

 Reference Signs List 5 crank angle sensor 10 vehicle engine control device 11a no-load state determination means 11b warm-up state determination means 12 combustion control unit 12a engine speed control unit (control means) 13 rotation speed calculation unit 20 engine 21 injector Ne engine rotation speed Nm Speed limit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G084 AA00 BA03 BA13 CA02 CA03 DA10 DA35 EA11 EB12 EB13 EB16 EC03 FA18 FA20 FA33 3G301 HA01 HA04 JA21 JA34 KA05 KA07 KB04 LB04 MA24 NA08 ND03 ND04 ND12 NE18 NE01 PE08Z PF01Z PF03Z PF08Z

Claims (1)

[Claims] A rotational speed detecting means for detecting a rotational speed of the engine; and a fuel supply to the engine is restricted based on detection information from the rotational speed detecting means. Control means for controlling the number of revolutions of the engine so as to prevent the engine from rotating, and no-load state determining means for determining whether the engine is in a no-load state; and a warm-up state for determining a warm-up state of the engine. When the engine is in a no-load state based on the detection information and the determination information from the rotation speed detecting means, the no-load state determining means, and the warm-up state determining means, Controlling the engine speed within a first speed limit less than the maximum speed, and setting the first speed limit in a no-load state and before the engine completes warm-up; Than The engine control device for a vehicle, wherein the engine speed is controlled within a second lower limit speed.