JP2000274288A - Electronic fuel injection engine with mechanical governor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure certain start-up an electronic fuel injection engine using a mechanical governor. SOLUTION: This electronic fuel injection engine with a mechanical governor 6 for adjusting an opening of a throttle valve 5 by unbalance between a governor force and a tensile force of a governor spring 16 has a starting throttle valve opening set part 22 for setting the opening of the throttle valve 5 to a start proper opening at the time of start-up of the engine, and a control part 10 for controlling a fuel injection device 4 to inject a start-increased fuel for a prescribed period from the operation time of a starter switch 21. By providing the starting throttle valve opening set part 22, the opening of the throttle valve 5 can be set to the start proper opening at the time of the start-up of the engine, so that an air amount taken into a combustion chamber 1 by starting of the starter switch 21 can be set to an amount suitable for the start-up to secure the certain start-up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic fuel injection engine, and more particularly, to an electronic fuel injection engine with improved startability.

[0002]

2. Description of the Related Art Generally, an electronic fuel injection engine controls an injection amount by setting an injection time of a fuel injection valve in a fuel injection device. In such an engine, the cooling water temperature is detected at the time of starting, and when the cooling water temperature is low, the fuel injection time is set longer to increase the fuel injection amount, thereby improving the startability.

[0003]

Further, the applicant of the present invention has disclosed in Japanese Patent Application No. 9-255864 an electronic fuel injection system in which the opening of a throttle valve for controlling the amount of supplied air is adjusted by a mechanical governor. Propose an engine. The mechanical governor of this electronic fuel injection engine has a throttle valve and a governor lever interlockingly connected to each other, a governor force generated by a flyweight is applied to the governor lever to bias the throttle valve in a valve closing direction, and a governor connected to the governor lever. The throttle valve is urged in the valve opening direction by the tension of the spring, and the opening degree of the throttle valve is adjusted based on the imbalance between the governor force and the governor spring tension.

In the configuration employing the mechanical governor, since no governor force is generated at the time of starting, the throttle valve is fully opened due to the tension of the governor spring. Therefore, the control unit of the electronic fuel injection engine has a problem in that even if the fuel is increased at the time of starting, the intake air amount becomes too large, the starting performance is poor, and the engine cannot be started properly.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic fuel injection engine which can solve the above problems. An example of a specific purpose is as follows. (a) In an electronic fuel injection engine using a mechanical governor, secure starting is ensured. (b) In an electronic fuel injection engine using a mechanical governor, the operation of the engine does not become unstable during the transition from the start of the engine start to the steady operation,
Enable smooth and stable transition to normal operation. (c) Even if the mechanical governor is used, extra work performed by the engine operator is reduced as much as possible. It should be noted that the problems of the invention other than those described above and the means for solving the problems will be described in detail in the description in the following specification.

[0006]

The present invention will be described below with reference to, for example, FIG. 1 showing an embodiment of the present invention. The first invention includes a fuel injection device 4, a throttle valve 5 for adjusting the amount of air flowing into the combustion chamber 1 of the engine, a governor force and a governor spring 16.
A mechanical governor 6 for adjusting the opening of the throttle valve 5 in an unbalanced state with the tension of the engine; and a starting throttle valve opening setting means 2 for setting the throttle valve 5 to a suitable opening 49 for starting the engine when the engine is started.
2, and a control means 10 for injecting the fuel which has been started and increased into the fuel injection device 4 for a predetermined period starting from the time when the starter switch 21 is operated. The second invention is characterized in that the amount of the fuel to be started and increased is determined based on a liquid temperature related to the engine. The third invention is characterized in that the end of the predetermined period is set when the first explosion of the engine is detected. A fourth invention is characterized in that the detection of the first engine explosion is detected based on at least one of the engine speed and the rate of change of the engine speed.

[0007] The first to fourth inventions will be further described. Throttle valve opening setting means 2 at start-up in the first invention
No. 2 may be a manual type or an automatic type. The predetermined period may be a method in which a predetermined period is stored in advance in the storage unit of the control unit, and the length of the predetermined period is changed based on a temperature relating to the engine, for example, a liquid temperature of the engine or an intake air temperature. You can also do so. In this case, if the temperature relating to the engine is low, the predetermined time may be lengthened.

As an example of the setting in the second invention, when the liquid temperature is low, the fuel injection amount is increased, and when the liquid temperature is high, the fuel injection amount is decreased. Therefore, assuming that the basic injection time at the start of the start is T _s0 and the correction coefficient K _{s0 of the} fuel increase at the start of the start based on the engine coolant temperature, the injection time T _s at the start of the start is at least T _s = T There is a method of obtaining the equation including the equation of _s0 · _Ks0 .

[0009]

According to the first aspect of the present invention, even in an electronic fuel injection engine using a mechanical governor, the throttle valve is set to a suitable opening at the start of the engine by the starting throttle valve opening setting means. Therefore, the amount of air taken into the combustion chamber by starting the starter can be set to a small amount suitable for starting. Further, the control means causes the fuel injection device to inject the fuel increased in starting amount for a predetermined period starting from the start of the operation of the starter switch. Failure can be reduced. That is, according to the first invention, the above-mentioned problem can be solved. Further, unnecessary fuel injection can be eliminated by injecting the fuel that has been increased in the predetermined time by a period necessary for starting.

According to the second aspect of the present invention, the amount of fuel to be increased in starting is determined based on the liquid temperature relating to the engine. Therefore, the amount of fuel to be increased in starting based on the temperature of the engine is set to a suitable amount for starting. Can be set. Third
According to the present invention, after the engine explodes for the first time, the fuel whose starting amount is increased is not supplied. Therefore, by supplying a large amount of fuel set for the first explosion even after the first explosion, it is possible to prevent the ignition plug from being covered, the harmful components of the exhaust gas from increasing, and the generation of smoke. The present invention is based on the fact that the fuel injection amount required at the start of engine start is much larger than the fuel injection amount set at the time of transient engine start or at the time of steady operation.

According to the fourth aspect of the invention, when the engine first explodes, the rotation of the engine increases and the rate of change of the engine speed increases. Therefore, the first explosion of the engine can be confirmed by detecting the rate of change of the engine speed. . Further, by detecting the rate of change of the engine speed, there is an advantage that the time delay in detecting the engine speed is small. Further, since the engine speed can also be detected by a normally provided crank angle sensor, the configuration can be simplified and at low cost.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of a general-purpose electronic fuel injection engine of the present invention. The general-purpose electronic fuel injection engine E includes a fuel spark plug 2 provided facing a combustion chamber 1 of the engine, a fuel injection device 4 provided in an intake pipe 3, and an amount of air flowing into the combustion chamber 1. , A mechanical governor 6 for controlling the opening of the throttle valve 5, a pressure sensor 7 for detecting the pressure p in the intake pipe 3, and an engine rotation by detecting a crank angle signal for a certain period. A rotational speed sensor 9 for detecting the number n, an intake air temperature sensor 18 for detecting the intake air temperature of the intake pipe 3, and an engine liquid temperature sensor 19 for detecting the temperature t of the engine coolant.
And a valve opening sensor 8 for detecting the opening of the throttle valve 5. Further, a start-time throttle valve opening degree setting unit 22 and a start-time throttle valve opening degree release unit 28 are provided so as to be connected to the throttle valve 5. When the start-time throttle valve opening setting means 22 and the start-time throttle valve opening canceling unit 28 are set to be automatic, an actuator 23 (see FIG. 6) is provided in addition to the throttle valve 5 and the starter switch 21 is turned on. Is detected, the actuator 23 sets the throttle valve 5 to the start appropriate opening degree 49 (see FIG. 6), and in response to the detection of the first explosion of the engine, the actuator 23 sets the throttle valve 5 to It is configured to set to the starting release posture.

In FIG. 1, at a predetermined position in the exhaust passage,
A three-way catalyst 11 is provided, and an air-fuel ratio λ of the engine is provided at an upstream position or a downstream position based on the oxygen concentration in the exhaust gas.
Is provided. FIG. 1 shows a configuration in which an air-fuel ratio detection sensor 20 is provided at a downstream position. Although FIG. 1 shows only the injection valve, the fuel injection device 4 actually includes a fuel tank, a fuel pump for pumping fuel to the injection valve, and the like.

The general-purpose electronic fuel injection engine E includes:
A control unit 10 composed of a microcomputer for performing general control is provided. The control unit 10 includes a detection pressure p of the pressure sensor 7, an engine speed n from the speed sensor 9, and intake air from the intake temperature sensor. Temperature t, the temperature t of the engine coolant from the engine liquid temperature sensor 19, the air-fuel ratio λ from the air-fuel ratio detection sensor 20, the valve opening θ from the valve opening sensor,
A starter operation signal of the starter switch 21 is input. The injection pulse signal of the control unit 10 is output to the fuel injection device 4 to open the valve, and the injection amount is set based on the calculation of the control unit 10 according to the length of the injection time.

In the case of a multi-cylinder engine, it is general that each intake pipe is connected to each cylinder via a surge tank chamber 12, and each fuel injection device 4 is provided for each intake pipe. . The mechanical governor 6 includes, for example, a governor lever 14 swingably supported on a governor shaft 13 and a governing lever 1 for setting an engine rotation speed by an operator.
5, the governor spring 16 is connected, the operating rod 17 of the throttle valve 5 is connected to one end of the governor lever 14, the governor spring 16 is connected to the other end of the governor lever 14, and the governor spring 16 is regulated. It is operatively connected to the lever 15. By applying governor force (GF) to the governor lever 14, the throttle valve 5 is driven in a direction to close, and the governor spring 16 is driven to open the throttle valve 5 in tension. That is, the opening degree of the throttle valve 5 is controlled based on an imbalance between the governor force (GF) and the tension of the governor spring 16.

The valve opening sensor 8 is configured to detect the rotation of the governor shaft 13. With this configuration, the valve opening sensor 8 can be stably supported, and the governor lever 14 and the throttle valve 5 can be supported. The effect of the operation delay of the connecting rod 17 and the like can be reduced. However, it is also possible to provide a valve opening sensor 8 at the position of the throttle valve 5.

FIG. 2 shows a control unit 10 according to this embodiment.
6 is a control flowchart performed by the control unit. Referring to FIG.
The flow of FIG. 2 will be described. First, in step SP1, it is determined whether or not the starter switch 21 is on,
If it is determined that the starter switch 21 is turned on, the intake negative pressure p, the engine speed n, the engine fluid temperature t, etc. are detected in step SP2, and in step 3, based on at least the engine fluid temperature t. calculates the beginning of startup-time fuel injection time T _s and injection speed change rate whether or engine speed of the engine whether or not initial combustion has become a value that exceeds the rotational speed of the starter motor in step SP4 (dn / dt) is determined to be greater than or equal to a predetermined value. If it is determined that the first explosion has occurred, step SP5
In step (1), the injection time during transition _Tk is set based on the injection amount map during startup transition, and the injection is performed by setting the injection amount until the idle rotation speed is reached. On the other hand, when the initial combustion of the engine is not detected at step SP4, the flow returns to step SP2, to continue the process of injecting in the startup transient injection time T _k including at least a liquid temperature correction step SP3. Then, in step SP6, it is determined whether or not the engine speed has reached the idle speed, and if it is determined that the engine speed has not reached the idle speed, the process proceeds to step SP6.
Injection is continued according to the startup transient injection amount map of No. 5, and when it is determined that the idling engine speed has been reached, injection is performed according to the normal operation injection time _{Tc according} to the normal operation map.

The operation of this embodiment will be further described. FIG. 3 (A) shows the change in the engine speed at the start of cold start and cold start, transition of start, and steady operation, with time on the horizontal axis.
FIG. 3 (B) shows the value of the air-fuel ratio on the horizontal axis on the same time axis, and FIG. 3 (C) shows the drive signal of the solenoid as the actuator. FIG. Note that, in this specification, at the start of starting 2
4 is the period from when the starter switch is turned on (t0) to the first explosion (t1).
Time to time (t2) from 1) reaches the idle speed n _a, the steady operation time 26 is used as a term indicating a period of stable operation condition of the idling rotation n _a subsequent. In FIG. 3 (A), by the rotation of the starter motor starter switch is turned on at t0, the engine speed gradually increases to rotate at a rotational speed n _s of predetermined starter motor, the initial explosion of the engine in the meantime Done.

In this embodiment, step SP3
Injection time T at start 24 indicated by _sTo T_s= T_s0・ K_s0・ K_v0 Including the formula. Where T_s0At the start of startup.
And start increasing when the starter switch is turned on.
This is the basic injection amount when This T_s0Is the intake negative pressure p and
Calculating the intake air amount Q from the gin rotation speed n,_s0= A · Q / n. Here, a is a constant. Also described later.
Basic injection amount consisting of intake negative pressure p and engine speed n
It may be set on the map. K_s0Is a star as shown in FIG.
When the data switch is operated, the
Is a coefficient for correcting the fuel increase. Increased volume when water temperature is low
If the water temperature is high, the weight loss ratio is low.

K_v0Is the correction factor for the battery voltage of the starter
The correction is made so that the correction coefficient increases as the temperature decreases.
You. In addition, besides these correction coefficients, the correction based on the intake air temperature
Coefficient K _aMultiply by 24, etc. at the start of final startup
Firing time T_sIs calculated. Detection of the first explosion in step SP4
Is a threshold value that determines whether the rotation speed of the starter motor has exceeded
May be detected by comparing
The rate of change of the number, that is, the rise of the rotation rate change curve in FIG.
The rising slope 27 is a predetermined threshold value set in advance.
When it exceeds, it may be detected that the first explosion occurred. First explosion detector
The stage is constituted by the comparator and the like.

In the transitional injection time T _k at the start of step SP5
Is calculated including the equation of T _k = T _k0 · K _k0 · K _v0 . Here, the setting of the basic injection amount T _k0 at the start transition time 25 is based on the start transition injection amount map that determines the basic injection amount T _k0 based on the values of the intake negative pressure p and the rotation speed n as shown in FIG. Done in Starting transient injection quantity map includes a rotational speed from the rotational speed n _s of at least a starter motor to idling speed n _a, as the intake negative pressure p parameter, the data of the basic injection amount lattice points . Incidentally, the rotation speed from the rotation 0 in FIG. 5 to the idle rotation speed n _a, are mapped having indicates the basic injection quantity data of the intake negative pressure p as a parameter. Data between each grid point is calculated by interpolation between adjacent grid points. After the first explosion, K _v0 becomes almost 1.

[0022] The newly provided because of the start-up transient injection amount map from the initial explosion to the idle speed n _a is as follows. If the mechanical governor is provided, at least the first explosion of the engine can be performed so that the governor force and the governor spring are unbalanced and the engine speed can be controlled to be stable. In this state, when shifting from the initial explosion speed to the idle speed, the fuel injection amount is set so that the shift operation can be performed stably and the fluctuation after reaching the idle speed is minimized. Is the above-described starting transient injection amount map. As described above, the values of the injection amount map during the transition to the start are set on the premise of the presence of the mechanical governor. It should be noted that the values of the transient injection amount map at the start-up transition time shown in FIG. Is set over a wide range in consideration of the amount of overrun due to transient phenomena beyond the range. K _k0 is a correction coefficient for increasing the fuel based on the cooling water temperature of the engine up to the idle speed after the initial explosion. When the water temperature is low, the weight is increased, and when the water temperature is high, the weight is reduced.
_Same as K _s0 . Incidentally, by multiplying the like correction coefficient K _a according to the intake air temperature in addition to these correction factors to calculate the injection time T _k of the final start-up transient 25.

The setting of the steady operation injection time _Tc in step SP7 is the same as the injection amount control that is normally performed from the idle rotation to the rated rotation. Normally, intake negative pressure p and engine speed n (from idle speed to maximum speed)
(MAP) for setting the basic injection amount based on the map data based on the map data. Alternatively, there is a method of setting a basic injection amount by a method of setting map data (TAP) based on the throttle valve opening θ and the engine speed n. When the feedback control based on the air-fuel ratio is adopted, the injection amount according to the state of the engine is obtained by multiplying the basic injection amount by the feedback correction coefficient based on the detected air-fuel ratio. On the other hand, in the state of the start 24 and the transition 25 of the start shown in FIG. 3, it is preferable to perform open control instead of feedback control in order to secure responsiveness.

Next, an automatic starting throttle valve opening setting section,
An example of the start-time throttle valve opening canceling unit will be described. In this embodiment, the starting throttle valve opening setting unit 22 and the starting throttle valve opening canceling unit 28 are configured by a mechanism including one actuator 23 provided in the throttle valve 5. FIG. 6 (A)
As shown in (1), the throttle valve 5 is provided in the intake passage 40, and the throttle valve input lever 43 is fixed to the valve shaft 42 of the throttle valve 5. The throttle valve input lever 43 is fixed to the outer end of the valve shaft 42.

The starting throttle valve opening setting unit 22 and the starting throttle valve opening canceling unit 28 are provided with a valve opening setting lever on the outside of the base body 44 in order to smoothly perform a cold start of the engine. 45, and the valve opening setting lever 45 is provided.
6A, a receiving portion 46 is provided.
As shown in FIG. 6 (B), the valve opening setting lever 45 can be switched between a start setting posture 47 and a start release posture 48, and as shown in FIG.
When the throttle valve 5 is switched to the start setting posture 47 and the receiving portion 46 receives the throttle valve input lever 43, the throttle valve 5 becomes the start setting posture 47 with the start appropriate opening degree 49, and as shown in FIG. Release the opening degree setting lever 45 to the starting release position 48
Is switched to, the receiving portion 46 is set to the throttle valve input lever 4
3 so as to retreat to a position where it does not interfere.

The receiving portion 46 is formed at the distal end of the valve opening setting lever 45, and the base end of the valve opening setting lever 45 is an input portion 50. To switch the valve opening setting lever 45, the input unit 50 of the valve opening setting lever 45 is connected to a push-pull rod 52 via a push-pull wire 51.
It is linked and linked. The push-pull rod 52 is integrated with the movable iron piece 54 of the solenoid 53. Then, as shown in FIG. 6A, the starter switch 2 shown in FIG.
When the switch 1 is turned on, the drive switch 55 of the sonolide 53 is turned on in conjunction therewith, the push-pull rod 52 is pulled, and the valve opening setting lever 45 is set in the starting setting posture 47.
It is made to switch to.

A tongue 56 is provided on the valve opening setting lever 45, and the tongue 56 comes into contact with a stopper 57 of the base body 44, and the posture in which the rotation stops is the starting setting posture of the valve opening setting lever 45. 47. The tongue 5 is attached to the throttle valve input lever 43.
When the valve opening degree setting lever 45 is in the starting setting posture 47 as shown in FIG.
When the tongue piece 58 comes into contact with 6 and the rotation stops, the throttle valve 5 has the start-appropriate opening degree 49.

The start appropriate opening degree 49 of the throttle valve 4 is set according to the specifications of each electronic fuel injection engine. The valve opening setting lever 45 is urged by a return spring (not shown). As shown in FIG. 6B, when the push-pull rod 52 is pushed back by the OFF operation of the solenoid drive switch 55, the valve is opened. The degree setting lever 45 returns to the starting release posture 48. Valve opening setting lever 4
When the throttle valve 5 is in the starting release position 48, the throttle valve 5 can be opened and closed over the entire range 59 without causing interference between the throttle valve input lever 43 and the receiving portion 46.

The input portion 60 of the throttle valve input lever 43 is linked to the speed control lever 15 via the connecting rod 17 and the mechanical governor 6 in order to open and close the throttle valve 4.
The mechanical governor 16 includes a governor lever 14 and a governor spring 16, and includes a governing lever 15 and a governor lever 1.
A governor spring 17 is interposed between the throttle valve 4 and the biasing force 18 of the governor spring 17 to rotate the throttle valve input lever 6 in the direction in which the throttle valve 4 is fully opened. The provision of the automatic start-time throttle valve opening setting unit 22 and the start-time throttle valve opening release unit 28 reduces the burden on the operator as compared with a configuration in which the push-pull rod 52 is manually pulled. However, a configuration in which the push-pull rod 52 is manually pulled as needed can be adopted.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of an electronic fuel injection engine of the present invention.

FIG. 2 is a flowchart showing an outline of a basic process performed by a control unit.

FIG. 3 (A) is a diagram showing a change in the number of revolutions at the start of a start in cold and cold, during a start transition, and during a steady operation, and FIG. 3 (B).
FIG. 3 is a diagram showing an air-fuel ratio at that time, and FIG. 3C is a diagram showing an operation signal of a solenoid as the actuator.

FIG. 4 is a diagram showing a relationship between a cooling water temperature and a start-up start fuel increase correction coefficient K _s0 .

FIG. 5 is a diagram illustrating an example in which a basic injection amount is held as map data including an engine speed and an intake negative pressure.

FIGS. 6A and 6B are diagrams showing the configuration of an automatic start-time throttle valve opening setting unit and a start-time throttle valve opening release unit, respectively.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Combustion chamber, 4 ... Fuel injection device, 5 ... Throttle valve, 6 ... Mechanical governor, 10 ... Control unit, 16 ... Governor spring, 21 ... Starter switch, 22 ... Start-up throttle valve opening setting unit, 49 ... Start Suitable opening.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02D 31/00 301 F02D 31/00 301A 310 310C F term (reference) 3G065 CA00 CA22 DA07 DA08 EA01 FA07 GA09 GA10 GA27 GA41 HA21 HA22 KA05 3G301 HA01 JA00 JA23 JA24 KA01 KA11 LA03 LB02 LC01 LC09 MA13 MA14 NC02 ND14 NE01 NE06 NE23 PA07Z PA10Z PA11A PA11Z PD02Z PE01A PE01Z PE02Z PE03Z PE08Z PF16Z PG01Z

Claims (4)

[Claims] An imbalance between a fuel injection device (4), a throttle valve (5) for adjusting an amount of air flowing into a combustion chamber 1 of an engine, and a tension of a governor force and a governor spring (16). Mechanical governor (6) for adjusting the opening of the throttle valve (5)
When the engine is started, the throttle valve (5) is started at the appropriate opening.
Starting throttle valve opening setting means (22) set in (49);
Electronic fuel injection with a mechanical governor, characterized by comprising control means (10) for injecting the fuel which has been started and increased into the fuel injection device (4) for a predetermined period starting from the time of operation of the starter switch (21). engine. 2. An electronic fuel-injection engine with a mechanical governor according to claim 1, wherein the amount of fuel to be started and increased is determined based on a liquid temperature of the engine. Injection engine. 3. An electronic fuel injection engine with a mechanical governor according to claim 1, wherein the predetermined period is terminated when an initial explosion of the engine is detected. 4. An electronic fuel injection engine with a mechanical governor according to claim 3, wherein the detection of the first engine explosion is detected based on at least one of an engine speed and an engine speed change rate. , Electronic fuel injection engine with mechanical governor.