JP2525106Y2 - Injection amount control device at engine start - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a device for controlling an injection amount when starting an engine.

<Conventional technology> As a two-stroke engine used for motorcycles and snowmobiles, which employs a fuel supply system using a carburetor, the exhaust port is opened during the scavenging process. The air-fuel mixture (fresh air) passes through the cylinder together with the combustion gas, and has the disadvantage of poor fuel economy.

For this reason, an electronically controlled fuel injection system using a fuel injection valve has been adopted from a conventional fuel supply system using a carburetor (see Japanese Patent Application Laid-Open No. 63-255543). For example, fuel is supplied to an intake manifold section for each cylinder. There is an injection valve provided with an injection valve so that all cylinders are simultaneously injected.

The starting injection amount control in the two-cycle engine using the electronic control fuel injection system is performed as follows.

That is, in order to improve the startability, the fuel injection amount is determined so as to be slightly larger than the normal fuel injection at the time of starting.

For example, at the start of the ignition switch, that is, at the time of cranking, a value calculated by the following equation is output.

_{Ti = T cs × K 1 ×} K 2 where, Ti: starting injection pulse width T _cs: startup basic injection amount K _1: rotational speed correction coefficient K _2: time correction coefficient the startup basic injection quantity, engine temperature In this case, the injection amount and the rotation speed correction coefficient stored in advance change according to the cranking rotation speed, and the time correction coefficient changes according to the cranking time.

<Problems to be Solved by the Invention> By the way, in such a two-stroke engine and other engines, fuel is injected after the engine is rotated as described above. It took a long time to reach it and a long time before the engine started.

For this reason, there is a type in which fuel is injected when the engine is not rotating (key switch ON, that is, a method in which a single injection is performed when the power is turned on). Irrespective of the key switch is turned on.

For example, even when the key switch is turned on and the engine is not started, or when the key switch is repeatedly turned on and off, the fuel is injected, and the control method is not always appropriate.

Therefore, the present invention has been made in view of the above-mentioned conventional problems,
In order to reflect the driver's intention when the engine key switch is turned on, the conventional problem is solved by pre-injecting the fuel determined by the engine temperature etc. only when certain predetermined conditions are met. It is an object of the present invention to provide an engine start-time injection amount control device with improved operability.

<Means for Solving the Problems> For this reason, the engine start-time injection amount control device of the present invention has a fuel injection valve as shown in FIG. Means for setting a pre-stored basic pre-injection amount based on the cooling water temperature of the engine when the opening of the throttle valve changes to a predetermined change state within a predetermined time at a predetermined engine speed or less; And a means for correcting according to the number of injections.

<Operation> In such a configuration, when the engine key switch is turned ON, only when certain predetermined conditions are met, that is, when the throttle valve is in a predetermined change state within a predetermined time at a predetermined engine speed or less, the water temperature at that time is changed. The fuel determined by the intake air temperature and the number of injections is pre-injected. As a result, the pre-injection can be executed according to the intention of the human being to start, and as a result, the optimal pre-injection can be performed, so that the startability can be improved.

The condition setting of "when the opening degree of the throttle valve changes to a predetermined change state within a predetermined time" is set to a certain rapid change of the throttle valve opening degree in order to reflect the driver's intention to start the engine. The pre-injection is performed based on the driver's intention, and the startability can be further improved.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 shows a control system diagram of a two-cycle engine as one embodiment of the present invention.

That is, in the drawing, air is drawn into the main body 11 of the two-stroke engine from an air cleaner (not shown) via a throttle valve 12 linked to an accelerator, and further via an intake manifold 13.

A fuel injection valve 14 is provided for each cylinder in a branch portion of the intake manifold 13. Each fuel injection valve 14 is an electromagnetic fuel injection valve that is energized by a solenoid, opens, is deenergized, and closes, and is energized by a drive pulse signal from a control unit 15 to open,
The fuel pumped from a fuel pump (not shown) and adjusted to a predetermined pressure by a pressure regulator is supplied to the engine body 11.
To be injected.

The control unit 15 receives output signals from various sensors, performs arithmetic processing by a built-in microcomputer, determines a fuel injection amount (injection time) Ti and an injection timing (injection method), and outputs a drive pulse signal according to the fuel injection amount (injection method). Output to the injection valve 14.

As the various sensors, an air flow meter 16 is provided upstream of the throttle valve 12, and outputs a signal corresponding to the intake air amount Q. Further, a crank angle sensor 17 is provided so as to be built in a distributor (not shown).
A reference signal is output every 0 °. Here, the engine speed N can be detected by measuring the period of the reference signal.

The throttle valve is provided with a potentiometer type throttle sensor 18 and outputs a signal corresponding to the opening α of the throttle valve 12. Further, a water temperature sensor 19 is provided on a water jacket of the engine body 11, and outputs a signal corresponding to a cooling water temperature Tw as an example of the engine temperature.

In the case of a two-cycle engine, fresh air is supplied to the combustion chamber via the crankcase chamber, and thus is directly affected by the crankcase temperature. Therefore, a crankcase temperature may be used instead of the cooling water temperature as the engine temperature.

Further, the voltage of the battery 20 is applied to the control unit 15 as its operation power supply for detecting the power supply voltage VB.

Next, the fuel injection control at the time of starting by the microcomputer in the control unit 15 will be described based on the flowchart of FIG.

That is, step (hereinafter abbreviated as S as in the figure) 1
It is determined whether or not is at the time of starting (at the time of starting the ignition switch).

At the time of starting, the basic injection amount at startup Tcs is searched from the cooling water temperature Tw detected by the water temperature sensor 19 as an example of the engine temperature in S2. Then, to find the rotational speed correction coefficient K ₁ which are predetermined in accordance with this the rotational speed N of the engine in S3.

Next, at S4, the search time correction factor K ₂ which is determined accordingly based on the cranking time T.

Then, in S5, the injection pulse width Ti at the time of starting is calculated based on the equation shown above, and control is performed based on this.

Except during start-up, the process proceeds from S1 to S6 to perform normal Ti control calculation.

Here, based on detection signals output from the key switch 21, the crank angle sensor 17, and the throttle sensor 18 of the engine, the control unit 15 is turned on when the key switch 21 is Means for setting a basic pre-injection amount stored in advance based on the cooling water temperature of the engine when the opening degree of the throttle valve 12 changes to a predetermined change state within a predetermined time, and setting the basic pre-injection amount to the intake air temperature. There are provided means for making a correction in accordance with the number of injections, and means for making a correction in accordance with the number of injections.

The operation of each means described above will be described based on the pre-injection control routine of FIG.

In S11, it is determined whether or not the key switch 21 of the engine is turned on. If the key switch 21 is not turned on, the process returns. If the key switch 21 is turned on, the process proceeds to S12 and the engine speed N is detected.
Proceed to. In S13, it is determined whether or not the engine speed N is equal to or less than a predetermined speed (for example, 10 rpm). If not, the process returns.
Proceed to. In S14, it is determined whether or not the throttle valve opening degree α has changed to a predetermined change state within a predetermined time. That is, the fifth
As shown in the time chart of FIG.
Is less than 5 ° for 1 second, and after the throttle valve opening α becomes 5 ° or more, the throttle valve opening α
Is determined to be 70 ° or more, and further reduced to 5 ° or less within 2 seconds.

If the throttle valve opening α does not change as described above, the process returns. If so, the process proceeds to S15.

In S15, the cooling water temperature T detected by the water temperature sensor 19
Based on w, a basic pre-injection amount T _PRE stored in advance is searched as shown in FIG. 6 (a).

Next, in S16, a predetermined intake air temperature correction coefficient _KTA is retrieved from the intake air temperature TA detected by an unillustrated intake air temperature sensor as shown in FIG. 6 (b).

Next, in S17, the number of injections after the power is turned on is counted, and in S18, the rotation correction coefficient K _n (injection) determined as shown in FIG. (The weight is reduced every time).

Then, in S19, based on the equation of Ti = T _PRE × K _TA × K _n ,
The pre-injection pulse width Ti is calculated, and in S20, the pre-injection pulse width T
Execute injection based on i.

Here, S15 is a means for setting the basic pre-injection amount of the present invention, S16 is a means for correcting the basic pre-injection amount according to the intake air temperature, and S18 is a means for correcting according to the number of injections. , Respectively.

With this configuration, when the engine key switch 21 is ON, only when certain predetermined conditions are met, that is, when the opening of the throttle valve 12 changes to a predetermined change state within a predetermined time at a predetermined engine speed or less, Since the fuel is determined by the pre-injection determined by the water temperature Tw, the intake air temperature TA, and the number of injections n, the pre-injection can be executed according to the intention of the human being to start, for example, the key switch 21 is turned on.
Even if you do not start the engine or turn on the key switch
-It is possible to prevent the fuel from being injected when the power is repeatedly turned off, and to perform the optimal pre-injection, thereby improving the startability.

That is, by setting the condition "when the opening degree of the throttle valve changes to a predetermined change state within a predetermined time", a certain rapid change of the throttle valve opening degree is reflected in order to reflect the driver's intention to start the engine. Can be confirmed, whereby the pre-injection based on the driver's intention is executed, and the startability can be further improved.

FIG. 7 is a time chart showing the operation of each element with the lapse of time from the time when the above-mentioned key switch is turned ON to the time after starting through pre-injection.

<Effects of the Invention> As described above, according to the engine start injection amount control device of the present invention, when the engine key switch is turned ON, the fuel determined by the engine temperature difference at that time only when certain predetermined conditions are met. Since the pre-injection is configured, the pre-injection can be executed by reflecting the intention of the person to start the engine, and the startability can be improved. By adding the condition setting when the opening changes to a predetermined change situation, it is possible to confirm a certain rapid change in the throttle valve opening to reflect the driver's intention to start the engine. Thus, the pre-injection based on the driver's intention is executed, and the practical effect that the startability can be further improved is increased.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a system diagram showing an embodiment of the present invention, FIG. 3 is a flowchart showing a fuel injection control routine at the time of starting, and FIG. FIG. 5 is a characteristic diagram for determining a change state of the throttle valve opening with respect to time,
6 (a) to 6 (c) are characteristic diagrams of a basic pre-injection amount, a correction coefficient according to the intake air temperature, and a correction coefficient according to the number of injections, respectively.
FIG. 7 is a time chart showing the operation of each element with the lapse of time from the time when the key switch is turned ON to the time after starting through pre-injection. 11 ... engine body, 14 ... fuel injection valve, 15 ... control unit, 17 ... crank angle sensor, 19 ... water temperature sensor, 21 ... key switch

Continuation of the front page (56) References JP-A-61-14440 (JP, A) JP-A-63-88240 (JP, A) JP-A-61-31635 (JP, A) JP-A-56-165966 (JP) , U)

Claims (1)

(57) [Scope of request for utility model registration] When a key switch of an engine is turned on and an opening degree of a throttle valve changes to a predetermined change state within a predetermined time while the engine is at a predetermined rotation speed or less, a fuel injection valve is provided.
Starting of an engine comprising: means for setting a basic fuel injection amount stored in advance based on engine temperature; means for correcting the basic fuel injection amount according to intake air temperature; and means for correcting the basic fuel injection amount according to the number of injections Time injection amount control device.