WO2015005213A1

WO2015005213A1 - Engine control device

Info

Publication number: WO2015005213A1
Application number: PCT/JP2014/067784
Authority: WO
Inventors: 吉田　哲
Original assignee: 株式会社デンソー
Priority date: 2013-07-10
Filing date: 2014-07-03
Publication date: 2015-01-15
Also published as: CN105392980A; JP2015017530A; JP6127787B2; CN105392980B

Abstract

When starting an engine (10), if the opening degree of a throttle valve (14) is determined to be greater than a prescribed degree on the basis of changes in intake pressure detected by an intake pressure sensor (16), an ECU (40) limits the operation of the engine (10). Also, the ECU (40) determines the occurrence of the initial combustion after the starting of the engine (10) is initiated, monitors changes of increase in engine speed after the initial combustion, and limits the operation of the engine (10) when the opening degree of the throttle valve (14) is determined to be greater than the prescribed degree on the basis of the changes of increase in engine speed.

Description

Engine control device

The present invention relates to an engine control device that controls the operation of an engine mounted on a vehicle.

For example, in a two-wheeled vehicle, when the engine is started by holding the handle, the throttle grip may be opened unintentionally, and there is a concern that the vehicle may start erroneously immediately after the engine starts due to the opening of the throttle. The Therefore, a throttle opening sensor for detecting the throttle opening is provided, and it is determined that the throttle valve is opened when the engine is started based on the detected value of the throttle opening sensor. When the throttle valve is opened, the engine is started. There has been proposed a technique for performing prohibition and alerting (see, for example, Patent Document 1).

JP 2013-35430 A

By the way, in recent years, it has been considered to reduce the number of sensors due to cost restrictions and the like. For example, omitting the throttle opening sensor has been studied. In this case, omitting the throttle opening sensor makes it impossible to grasp the opening state of the throttle valve. For this reason, there still remains a concern that the vehicle will start erroneously.

The main object of the present invention is to provide an engine control device that can suppress erroneous start of the vehicle without using the detection result of the throttle opening sensor.

Hereinafter, the means for solving the above-mentioned problems and the effects thereof will be described.

The present invention relates to an engine control device (40) applied to an engine (10) in which a pressure sensor (16) for detecting intake pressure and a throttle valve (14) are provided in an intake section (11). And a first determination means for determining whether or not an opening of the throttle valve is greater than or equal to a predetermined value based on a change in the intake pressure detected by the pressure sensor at the time of starting the engine; Means for limiting the operation of the engine when it is determined by the means that the opening of the throttle valve is greater than or equal to a predetermined value.

In the above configuration, when the engine is started, the throttle opening state is grasped using the relationship between the throttle valve opening and the intake pressure, and the engine is operated when it is determined that the opening of the throttle valve is greater than or equal to a predetermined value. Limit. In this case, the opening degree of the throttle valve can be grasped without directly detecting the opening degree of the throttle valve by a sensor. Thereby, it is possible to suppress the erroneous start of the vehicle without using the detection result of the throttle opening sensor.

Further, in addition to the above configuration, the monitoring means for monitoring the engine rotation speed after the initial explosion has occurred after the start of the engine, and the opening of the throttle valve based on the engine rotation speed after the first explosion has occurred Second determining means for determining whether or not the engine is greater than or equal to a predetermined value; and a second determining means for restricting the engine operation when the second determining means determines that the opening of the throttle valve is equal to or greater than the predetermined value. And a control means.

In the above configuration, as means for suppressing erroneous start of the vehicle due to opening of the throttle valve at the time of starting the engine, means for limiting engine operation based on the detection result of the pressure sensor (first control means), and initial explosion Means (second control means) for limiting the operation of the engine based on the engine rotation speed after birth. Thereby, it is possible to suppress erroneous start at the time of engine start without using the detection result of the throttle opening sensor, and also to suppress erroneous start at the time of engine start even when the pressure sensor is abnormal.

The block diagram which shows the outline of the engine control system in embodiment of invention. The flowchart which shows the procedure of engine starting control. The figure which shows the stroke of an engine, and intake pressure change. The figure which shows the relationship between a throttle opening and the raise change of an engine speed. The flowchart which shows the procedure of engine starting control in another form.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an engine control system is constructed for a single-cylinder gasoline engine mounted on a two-wheeled vehicle such as a scooter as a vehicle. In the control system, an electronic control unit (hereinafter referred to as an ECU) is used as a central fuel. Control of injection amount and ignition timing are to be implemented. First, the overall schematic configuration of the engine control system will be described with reference to FIG.

In the engine 10 shown in FIG. 1, an air cleaner 12 is provided at the most upstream portion of the intake pipe 11, and a throttle valve 14 is provided downstream thereof. The throttle valve 14 opens and closes in response to a turning operation of a throttle grip (not shown) provided on the vehicle handle. In this system, a throttle opening sensor for detecting the throttle opening is omitted for simplification of the configuration. An intake pressure sensor 16 for detecting intake pressure is provided on the downstream side of the throttle valve 14. Further, an electromagnetically driven fuel injection valve 17 is attached near the intake port of the intake pipe 11, and fuel is supplied to the fuel injection valve 17 from a fuel supply system (not shown).

An intake valve 21 and an exhaust valve 22 are provided in the intake port and the exhaust port of the engine 10, respectively, and an air-fuel mixture is introduced into the combustion chamber 23 by the opening operation of the intake valve 21, and the exhaust valve 22. The exhaust after combustion is discharged to the exhaust pipe 24 by the opening operation. A spark plug 25 is attached to the cylinder head of the engine 10 for each cylinder, and a high voltage is applied to the spark plug 25 at a desired ignition timing through an ignition device 26 including an ignition coil. By applying this high voltage, a spark discharge is generated between the opposing electrodes of each spark plug 25, and the air-fuel mixture introduced into the combustion chamber 23 is ignited and used for combustion.

The exhaust pipe 24 is provided with a catalyst 31 such as a three-way catalyst, and an upstream side of the catalyst 31 is provided with an O2 sensor 32 for detecting the air-fuel ratio of the air-fuel mixture with exhaust as a detection target. Further, the engine 10 receives a water temperature sensor 33 for detecting the temperature of the engine cooling water (engine water temperature), and a rectangular crank angle signal for every predetermined crank angle (for example, at a cycle of 30 ° CA) as the engine 10 rotates. An output rotation sensor 34 is provided.

In addition, a starter 36 (starting device) is mounted on the vehicle. When the user performs a predetermined start operation, the starter 36 is driven, and initial rotation is applied to the crankshaft of the engine 10. Although not shown, the vehicle has a continuously variable transmission (CVT) as a power transmission device for transmitting the power generated by the engine 10 to the wheels, and between the engine 10 and the continuously variable transmission. The centrifugal clutch provided is mounted.

The ECU 40 is mainly composed of a microcomputer including a CPU, a ROM, a RAM, and the like, and detection signals of the various sensors described above are input to the ECU 40. The ECU 40 executes various control programs stored in the ROM, thereby controlling the fuel injection amount of the fuel injection valve 17 and the ignition timing by the spark plug 25 based on the engine operating state. In this case, the fuel injection amount and ignition timing are controlled based on the intake pressure PM (engine load) detected by the intake pressure sensor 16 and the engine rotational speed NE detected by the rotation sensor 34.

By the way, when the engine 10 is started, if the throttle valve 14 is opened, it is considered that the vehicle may unintentionally start. For example, when the user unconsciously rotates the throttle grip, there is a concern about the occurrence of such inconvenience. That is, when the engine 10 is started and the engine rotational speed increases to be higher than the connection rotational speed of the centrifugal clutch so that the vehicle can be driven, there is a possibility that a false start unintended by the user, that is, a so-called pop-out occurs.

Therefore, in this embodiment, immediately after the start of the engine 10, the throttle opening state is determined based on the intake pressure PM detected by the intake pressure sensor 16. When it is determined that the throttle valve 14 is in the predetermined opening state, the operation of the engine 10 is restricted by stopping the operation of the engine 10 (that is, not permitting the engine operation). . For example, when it is determined that the throttle valve 14 is in an opening state that reaches the engine speed at which the vehicle will be driven, the operation of the engine 10 is stopped. If the intake pressure sensor 16 is abnormal, the throttle opening degree determination based on the detection result of the intake pressure sensor 16 becomes impossible. Therefore, as a preparation for when the intake pressure sensor 16 is abnormal, an increase change in the engine rotational speed NE after the first explosion of the engine 10 is monitored. When the throttle opening state is detected based on the monitored change in the engine rotational speed NE and it is determined that the throttle valve 14 is in an opening state that is equal to or higher than the engine rotational speed at which the vehicle can be driven. The operation of the engine 10 is restricted by stopping the operation of the engine 10.

FIG. 2 is a flowchart showing a procedure of engine start control, and this process is repeatedly performed by the ECU 40 at a predetermined cycle.

In FIG. 2, in step S <b> 11, it is determined whether or not the engine 10 is being started. For example, the start flag is set at the beginning of the engine start, and step S11 is affirmed on the condition that the start flag is set. If step S11 is affirmed, the process proceeds to step S12. Note that the start flag is reset when the engine speed increases and becomes stable after the engine is started.

In step S12, it is determined whether or not a predetermined negative pressure change of the intake pressure PM has occurred immediately after the starter 36 is started (immediately after the start of cranking). In this case, if the intake pressure sensor 16 is normal and the throttle opening is less than a predetermined value, a predetermined negative pressure change occurs in the intake pressure PM, and an affirmative determination is made in step S12. On the other hand, if the intake pressure sensor 16 is abnormal or the throttle opening is greater than or equal to a predetermined value, a predetermined negative pressure change does not occur in the intake pressure PM, and a negative determination is made in step S12.

Supplementally, as shown in FIG. 3, when the crankshaft is rotated by driving the starter 36, the intake pipe 11 has a negative pressure in the intake stroke and the compression stroke of the engine 10, and the level of the negative pressure is the throttle. It depends on the opening of the valve 14. At this time, if the throttle valve 14 is in a closed state (throttle opening <predetermined value), the negative pressure level is relatively large, and if the throttle valve 14 is in an open state (throttle opening ≧ predetermined value). The negative pressure level is relatively small. If the negative pressure change amount is equal to or greater than the predetermined value as indicated by the solid line in the figure, an affirmative determination is made in step S12. If the negative pressure change amount is less than the predetermined value as indicated by the broken line, a negative determination is made in step S12. .

Further, when an abnormality occurs in the intake pressure sensor 16, it is assumed that the detection signal is in an invariable state (for example, a state where the detection signal is stuck to the maximum value or the minimum value). Also in such a case, step S12 is performed.

If step S12 is affirmed, the process proceeds to step S13, and normal operation of the engine 10 is permitted. That is, fuel injection by the fuel injection valve 17 and ignition by the spark plug 25 are started.

If step S12 has been performed, the process proceeds to step S14 to determine whether or not the intake pressure sensor 16 is normal. Although the method for determining abnormality of the intake pressure sensor 16 is arbitrary, for example, when the sensor output is constantly held at a value different from the output value when atmospheric pressure is detected, it may be determined that there is an abnormality.

When step S14 is performed, the process proceeds to step S15, and the operation of the engine 10 is stopped. That is, fuel injection by the fuel injection valve 17 and ignition by the spark plug 25 are prohibited. When step S14 is performed, it can be determined that no negative pressure change has actually occurred in the intake pipe 11 and the throttle valve 14 is in an open state. Therefore, the operation of the engine 10 is stopped in order to suppress erroneous start of the vehicle.

Further, when step S14 is performed, the process proceeds to step S16, and it is determined whether or not the fail-safe operation of the engine 10 due to the abnormality of the intake pressure sensor 16 is being performed. And if fail safe driving | operation is not implemented, it will progress to step S17 and will drive | operate the engine 10 in order to start the said fail safe driving | operation. In the fail-safe operation, the fuel injection amount and the ignition timing are usually calculated using the intake pressure PM and the engine rotational speed NE as basic parameters, whereas the fuel injection amount and the ignition timing are calculated using only the engine rotational speed NE as basic parameters. The time is calculated. Further, for example, a predetermined limit vehicle speed (30 km / h) is determined, and the operation of the engine 10 is controlled so as not to exceed the limit vehicle speed (so-called low-speed fail-safe operation is performed).

After the fail-safe operation is started, an affirmative determination is made in step S16. In step S18, the engine speed NE after the first explosion is started after the operation of the engine 10 is started is acquired as the NE increase value. At this time, it is determined that the initial explosion has occurred based on the fact that the engine speed NE has reached the initial explosion determination value (for example, 1000 rpm) after the start of the engine 10, and a predetermined time has elapsed since the initial explosion (for example, 0) The engine speed NE at the time when (5 seconds have elapsed) is acquired as the NE increase value.

Thereafter, in step S19, it is determined whether or not the NE increase value acquired in step S18 is equal to or greater than a predetermined determination value K. The determination value K is determined on the basis of the rotational speed (for example, 3000 rpm) of the clutch connection in which the power of the engine 10 is transmitted to the transmission side through the centrifugal clutch in the vehicle. In the present embodiment, the determination value K is smaller than the rotational speed of the clutch connection, for example, K = 2500 rpm. At this time, since the change in NE after the occurrence of the first explosion depends on the throttle opening, it is possible to estimate the throttle opening for each time based on the NE increase value. If the NE increase value is larger than the determination value K corresponding to the allowable value of the throttle opening, it can be determined that the throttle opening is equal to or greater than a predetermined value and there is a risk of erroneous start of the vehicle due to opening of the throttle.

If an affirmative determination is made in step S19, the process proceeds to step S20, and the operation of the engine 10 (fail-safe operation) is stopped. If a negative determination is made in step S19, the process ends. Note that when a negative determination is made in step S19, the fail-safe operation has already been started, and when S19 = NO, the operation of the engine 10 (fail-safe operation) is continued.

In addition, when the operation of the engine 10 is forcibly stopped in steps S15 and S20, and then the start operation is performed again by the user, the process of FIG. 2 is performed again. If the throttle valve 14 is closed at that time (that is, if the determination in step S12 is YES or the determination in step S19 is NO), the vehicle is allowed to travel by allowing the engine 10 to operate. It becomes possible.

Next, the relationship between the throttle opening and the increase in engine speed NE will be described with reference to FIG. FIG. 4 shows NE changes at different throttle openings after the start of the engine 10, L1 shows NE changes at 0% throttle opening, L2 shows NE changes at 5% throttle opening, and L3. Indicates NE change at a throttle opening of 12.5%, and L4 indicates NE change at a throttle opening of 25%.

Now, the engine start (cranking) is started at the timing t1, and then the occurrence of the first explosion is determined at the timing t2. Here, there is almost no difference in the NE change from the start of the engine 10 until the first explosion occurrence timing or immediately after that, even if the throttle opening is different, but thereafter there is a difference in NE change depending on the throttle opening. Has occurred. At this time, the increase in the engine speed NE becomes steeper as the throttle opening increases.

At the timing t3 when the predetermined time ΔT has elapsed from the initial explosion determination (t2), the engine speed NE (NE increase value) differs depending on the throttle opening, for example, the throttle opening 12.5% (L3), When the throttle opening is 25% (L4), NE is equal to or greater than the determination value K. At this time, if the engine speed NE is greater than or equal to the determination value K at the timing t3, that is, if the throttle opening is at L3 or L4, there is a concern that the vehicle will start erroneously. Stop immediately. In the present embodiment, the engine 10 is forcibly stopped when the throttle opening is larger than about 12.5%.

Note that Nx in the figure indicates a rotation speed at which the centrifugal clutch is in a power transmission state in the vehicle (for example, Nx = 3000 rpm). In the conventional configuration, when the throttle opening is L3 and L4, if the operation of the engine 10 is continued, the engine rotational speed NE reaches Nx early, and accordingly there is a high possibility of erroneous start of the vehicle. Become. In this regard, according to the configuration of the present embodiment described above, the engine operation is stopped when the throttle opening is L3 or L4, so that erroneous start of the vehicle is suppressed.

According to the embodiment described above in detail, the following excellent effects can be obtained.

A configuration that stops the operation of the engine 10 (limits the operation) when the opening of the throttle valve 14 is determined to be greater than or equal to a predetermined value based on the detected value of the intake pressure by the intake pressure sensor 16 at the time of starting the engine; did. In such a configuration, it is possible to grasp the opening state of the throttle valve 14 without directly detecting the opening degree of the throttle valve 14 by a sensor, and to suppress the erroneous start of the vehicle without using the detection result of the throttle opening sensor. Can be achieved.

The configuration for suppressing the erroneous start of the vehicle due to the opening of the throttle valve 14 at the time of starting the engine includes means for stopping the operation of the engine 10 based on the detection result of the intake pressure sensor 16, and the engine speed after the first explosion occurs. And a means for stopping the operation of the engine 10 based on a rise change in NE. Thereby, even if the throttle opening sensor is not provided, it is possible to suppress erroneous start at the time of engine start, and furthermore, it is possible to suppress erroneous start at the time of engine start even when the intake pressure sensor 16 is abnormal. As a result, it is possible to appropriately control the engine start and to suppress the erroneous start of the vehicle.

When the intake pressure sensor 16 is abnormal, the operation of the engine 10 is not disabled thereby, but the engine 10 is configured to perform fail-safe operation. As a result, the vehicle can be evacuated when a sensor abnormality occurs. And since it judges whether a fail safe driving | operation is stopped or continued according to the NE rise change after the first explosion, a fail safe driving | operation can be implemented safely and appropriately.

The determination value K for determining the throttle open state based on the NE increase value after the first explosion was set to a value lower than the rotational speed at which the centrifugal clutch is in the connected state (power transmission state). As a result, the engine 10 is stopped before the centrifugal clutch is in the connected state, and erroneous start of the vehicle can be reliably suppressed.

(Other embodiments)
You may change the said embodiment as follows, for example.

In the above embodiment, the monitoring means for monitoring the NE increase change after the first explosion of the engine 10 is realized by acquiring the engine rotational speed NE at the time when a predetermined time has elapsed from the first explosion as the NE increase value. However, this may be changed as follows. For example, the engine rotational speed NE after the first explosion may be monitored, and the time required to reach a predetermined rotational speed (for example, 2500 rpm lower than the clutch connection rotational speed) may be acquired. In this case, when the required time is shorter than the predetermined time, it is determined that the opening degree of the throttle valve 14 is equal to or greater than the predetermined time.

In the above embodiment, as a means for restricting the operation of the engine 10 when the throttle opening is equal to or greater than a predetermined value, a means for immediately stopping the operation of the engine 10 is adopted (see FIG. 2). A means for limiting the engine rotation speed by adjusting the injection amount and the ignition timing and thereby limiting the operation of the engine 10 may be employed. Even in this configuration, it is possible to suppress the erroneous start of the vehicle.

Specifically, a process including the process of FIG. 5 may be performed instead of the process of FIG. In FIG. 5, the process of the replacement part is shown about the process after step S16 of FIG. 2, and the same step number is attached | subjected about the process same as FIG. In FIG. 5, after the fail-safe operation of the engine 10 is started, the process proceeds from step S <b> 16 to step S <b> 31, and it is determined whether or not the operation restriction is performed during the fail-safe operation. And if the driving | running | working restriction | limiting is not implemented, while performing the process of above-mentioned step S18, S19, if the judgment of step S19 is further YES (if NE increase value> K), it will progress to step S32. Then, the fuel injection amount and the ignition timing are limited (operation limit of the engine 10) in order to suppress an increase in the engine speed. That is, operation control is performed while fail-safe operation is continued. At this point, the vehicle speed is limited by fail-safe driving, but in addition to that, driving limitation (rotational speed limitation) for suppressing erroneous start is performed.

Then, after the operation limitation (S32) of the engine 10 is started, the process proceeds from step S31 to step S33, and it is determined whether or not to cancel the operation limitation. For example, if a predetermined time has elapsed since the start of the operation restriction, or if a predetermined time has elapsed since the start of the fail safe operation, it is considered that the throttle opening state has been released, and the operation proceeds to step S34 to restrict the operation. To release. Or the structure which measures the time when the NE is restrict | limited based on the monitoring result of engine rotational speed NE, and cancel | releases an operation restriction | limiting when the limit time exceeds predetermined time may be sufficient.

It should be noted that immediately after the start of the engine, if the predetermined negative pressure change of the intake pressure PM has not occurred and the intake pressure sensor 16 is abnormal (the determination in step S12 in FIG. 2 is NO and the determination in step S14) If the determination is YES), the engine speed may be limited by adjusting the fuel injection amount and the ignition timing.

In the above embodiment, the throttle opening sensor is omitted. However, the present invention may be applied to a system having a throttle opening sensor by changing this system. In such a case, for example, when the ECU 40 determines that the throttle opening sensor is abnormal, as described above, the process of limiting the operation of the engine 10 based on the detection result of the intake pressure sensor 16 and the initial explosion are performed. A process of limiting the operation of the engine 10 based on the increase in the engine speed NE after birth may be performed. That is, an effective configuration can be realized when the throttle opening sensor is provided but cannot be used.

A means for restricting the operation of the engine 10 based on the detection result of the intake pressure sensor 16 at the time of starting the engine, and a means for restricting the operation of the engine 10 based on a change in the engine rotational speed NE after the first explosion occurs. Of these, only the former means may be used to control the engine at the time of engine start.

Other than motorcycles, the present invention can be applied to any vehicle in which there is a concern that the vehicle may start erroneously immediately after starting the engine due to unintended throttle opening.

DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Intake pipe, 14 ... Throttle valve, 16 ... Intake pressure sensor, 40 ... ECU (1st determination means, 1st control means).

Claims

An engine control device (40) applied to an engine (10) in which a pressure sensor (16) for detecting intake pressure and a throttle valve (14) are provided in an intake section (11),
First determination means for determining whether or not an opening of the throttle valve is greater than or equal to a predetermined value based on a change in intake pressure detected by the pressure sensor at the time of starting the engine;
First control means for limiting the operation of the engine when the first determination means determines that the opening of the throttle valve is greater than or equal to a predetermined value;
An engine control device comprising:
Monitoring means for monitoring the engine rotation speed after the first explosion after the start of the engine;
Second determination means for determining whether the opening degree of the throttle valve is greater than or equal to a predetermined value based on the engine speed after the first explosion occurs;
Second control means for limiting operation of the engine when the second determination means determines that the opening of the throttle valve is greater than or equal to a predetermined value;
The engine control device according to claim 1, further comprising:
An abnormality determining means for determining presence or absence of abnormality of the pressure sensor;
Fail safe operation execution means for permitting operation of the engine to perform the fail safe operation of the engine when the abnormality determination means determines that the pressure sensor is abnormal;
Further comprising
The monitoring means monitors the engine speed after occurrence of the first explosion under the condition where the fail-safe operation is performed,
The second control unit stops the fail-safe operation when the second determination unit determines that the opening degree of the throttle valve is greater than or equal to a predetermined value, and the opening degree of the throttle valve is less than the predetermined value. The engine control device according to claim 2, wherein the fail-safe operation is continued when it is assumed.
The engine control apparatus according to claim 2 or 3, wherein the monitoring means monitors an increase in engine rotational speed after the first explosion.