JPH0246782B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic governor for an internal combustion engine, and more specifically, to an electronic governor for an internal combustion engine that can switch between high-low speed governor characteristics and all-speed governor characteristics.

For example, as a fuel regulating governor for a fuel injection pump for a diesel engine, it can be controlled to maintain a constant rotational speed at any rotational speed.
Therefore, we have developed two types of governors, one with all-speed governor characteristics that is particularly suitable for use in working machines, and the other with high-low speed governor characteristics that are suitable for driving vehicles, where the vehicle speed can be controlled with good feeling depending on how much the accelerator pedal is pressed. It is broadly divided into things that are prepared. Therefore, 1
When one diesel engine is used for both driving and work purposes, it is desirable to be able to selectively switch the governor characteristics to desired characteristics. As a device that satisfies such requirements, an electric governor for internal combustion engines has already been proposed, for example, as disclosed in Japanese Patent Laid-Open No. 148635/1983. However, in this proposed conventional device, the conditions for switching between the all-speed governor characteristic and the high-low speed governor characteristic are not determined, so if the switching is performed carelessly while driving or working, for example, the rotational speed of the internal combustion engine will increase. This has the disadvantage that there is a risk that the vehicle speed may suddenly change, resulting in an extremely dangerous driving situation.

Therefore, an object of the present invention is to provide an electronic governor for an internal combustion engine that can prevent the engine from falling into a dangerous operating state when switching between all-speed governor characteristics and high-low speed governor injection. It is about providing.

The present invention provides an electronic governor for an internal combustion engine in which an actuator for adjusting the injection amount of a fuel injection pump for an internal combustion engine is driven in response to an electrical signal indicating operating conditions of the internal combustion engine. means for outputting a first signal for all-speed characteristic control when the internal combustion engine is in a predetermined switchable operating state; a determining means for determining whether or not the signal is present, a specifying means for specifying either the first signal or the second signal, and the determining means detects that the predetermined switchable operating state exists; According to the above specified means, the above first
or a second signal, and means for driving the actuator in response to the signal output from the selection means.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an embodiment of a fuel injection pump for an internal combustion engine using an electronic governor according to the present invention. The fuel injection pump 1 is coupled to be driven by an internal combustion engine 2.
Fuel injected from the engine is supplied into each cylinder of the internal combustion engine 2 via the injection pipe 3. In the illustrated embodiment,
The internal combustion injection pump 1 is configured as a distribution type fuel injection pump, and in FIG.
Only the mechanical structure of the main part is partially shown in cross section, and illustration of other known mechanical structures is omitted.

The fuel injection pump 1 is provided with a control sleeve 5 fitted into a plunger 4 as an injection amount adjusting member.
is connected to an electromagnetic actuator 7 via a continuous rod 6. The electromagnetic actuator 7 is driven in accordance with a drive current supplied from the control unit 8 as described below, thereby positioning the control sleeve 5 along the axis of the plunger 4 and adjusting the injection amount. . Control sleeve 5 defined by electromagnetic actuator 7
A sensor coil 9 is attached to the electromagnetic actuator 7 for the purpose of detecting the position of the electromagnetic actuator 7. The sensor coil 9 is a variable inductance element configured so that its inductance value changes according to the amount of operation of the electromagnetic actuator 7, and the position detection circuit 10 to which the sensor coil 9 is connected is connected to the control sleeve 5. A position signal R, which is a DC voltage signal at a level corresponding to the adjustment position, is output.

A speed signal N indicating the engine speed of the engine 2 and an accelerator signal A indicating the operation amount of an accelerator pedal (not shown) are supplied to the control unit 8 from a rotational speed detector 11 and an accelerator detector 12, respectively. . The control unit 8 controls the drive current I supplied to the electromagnetic actuator 7 according to the signals A, N and the position signal R indicating the operating state of the engine, and increases the drive current I according to the operating state of the engine 2. The position of the control sleeve 5 is controlled so that low-speed governor characteristics or all-speed governor characteristics are obtained.

FIG. 2 shows a block diagram showing the control system of the apparatus shown in FIG. In response to the speed signal N and the accelerator signal A, the control data generation circuit 20 generates a first target data D ₁ indicating the current target injection amount necessary to obtain desired fuel governor characteristics.
A first target data generation circuit 13 that outputs the same, and second target data D that indicates the current target injection amount necessary to obtain the desired high and low speed governor characteristics in response to the speed signal N and the accelerator signal A. The _second target data generation circuit 14 outputs the second target data.
The first target data D ₁ and the first target data D ₂ are input from the discrimination circuit 15 to a changeover switch 16 operated by a changeover control signal C, and only one of the data is the target injection amount data. It is selected as D ₀ and is input to the sleeve position control circuit 17 to which the position signal R from the position detection circuit 10 is input.

Reference numeral 18 indicates first target data D ₁
or the first target data _D2 , and when selecting the all-speed governor characteristic, the switch 18 is switched as shown by the solid line; When selecting the high/low speed governor characteristic, it is switched as shown by the dotted line.

The switch 18 determines whether or not the engine 2 is in a predetermined operating state so that the switching operation of the changeover switch 16 is performed in response to the operation of the switch 18 only when the engine 2 is in a predetermined operating state. It is connected to a discrimination circuit 15 having functions. A speed signal N and an accelerator signal A are applied to the determination circuit 15, and based on these signals N and A, it is determined whether or not the engine 2 is in an idling operating state. That is, when it is determined from the accelerator signal A that the amount of depression of the accelerator pedal is zero, and it is determined from the speed signal N that the engine speed is below a predetermined value, it is determined that the engine 2 is in the idling operating state. Only when it is thus determined that the engine 2 is in the idle operating state, the control signal C according to the operating state of the switch 18 is output, and the changeover switch 16 performs the switching according to the operating state of the switch 18. state.

The sleeve position control circuit 17 converts the target injection amount data _D0 into a target sleeve position signal indicating the position of the control sleeve 5 necessary to obtain the injection amount indicated by the target injection amount data _D0 ,
The electromagnetic actuator 7 is driven and controlled so that the difference between the separately input position signal R and the target sleeve position signal becomes zero. As a result, the position of the control sleeve 5 (see FIG. 1) is controlled so that the injection amount indicated by the target injection amount data D ₀ is obtained. Therefore, the all-speed governor characteristic according to the data pattern of the first target data D ₁ outputted from the first target data generation circuit 13 or the second target data outputted from the second target data generation circuit 14 is determined.
The fuel injection amount can be controlled using any of the high and low speed governor characteristics according to the data pattern of the target data _D2 .

Each idling control characteristic in the above-mentioned all-speed governor characteristic and high-low speed governor characteristic is set to be substantially the same characteristic.

Therefore, according to such a configuration, the discrimination circuit 1
5, the changeover switch 16 is activated in response to the operation of the switch 18 only when the engine 2 is in an idling operating state. Therefore, the governor characteristics can be changed from one idling control characteristic curve to the other. The idling control injection pipe curve will be shifted. However, as described above, since both idling control characteristics are set to be substantially the same, it is possible to reliably prevent problems such as a significant change in the operating state of the engine 2 when changing the characteristics.

This will be explained with reference to FIG. FIG. 3 shows the idling control characteristic curve A, the partial load characteristic curve B when the accelerator operation amount is _A1 , and the second target data among the all-speed governor characteristics determined in the first target data generation circuit 13. Of the high and low speed governor characteristics determined in the generating circuit 14, an idling control characteristic curve c and a partial load characteristic curve d when the accelerator operation amount is the same as _A1 are shown, respectively. Here, the horizontal axis is the engine speed V, and the vertical axis is the control sleeve position P. As already explained, the idling control characteristic curves A and C are set to have substantially the same characteristics, so they are shown as the same characteristic curve in FIG. 3. Now, assuming that the load line of engine 2 is in the state shown by the dotted line in the diagram,
When the accelerator operation amount is A ₁ , the operating point when the engine 2 is controlled by the all-speed governor characteristic based on the first target data D ₁ is point A; on the other hand, when the accelerator operation is also A ₁ , the engine 2 2 is controlled by the high-low speed governor characteristic based on the first target data _D2 , the operating point is point B. Therefore, if the governor characteristics are changed by switching the switch 16 under the above-mentioned load condition, the operating point will move from point A to point B or from point B to point A. , the rotational speed of the engine 2 will change rapidly, which is extremely dangerous and also causes the problem of giving a large mechanical shock to the engine 2. Changes in the operating point due to differences in governor characteristics vary depending on the operating state of the engine 2 at that time, but in any case, large fluctuations in rotational speed are generally involved.

On the other hand, during idling, the operating point is at point C regardless of which governor characteristic is used, so even if the governor characteristic is switched, there will be no change in the operating state of the engine 2, as described above. This inconvenience will not occur at all.

The control data generation circuit 20 shown in FIG. 2 can also be realized using a microcomputer, and FIG. 4 shows a flowchart of an example of a program in that case. To explain the program shown in FIG. 4, after starting, in step a, it is determined whether or not the engine 2 is in an idling operating state. This determination is made as described above based on the speed signal N and the accelerator signal A. If the vehicle is in an idling state, the process proceeds to step b, where it is determined whether the switch 18 is open or closed. If switch 18 is in the state shown by the solid line in FIG. 1, instructing selection of the all-speed governor characteristic, step c.
If the all-speed flag is set in step d, and on the other hand, if the switch 18 is in the state shown by the dotted line in FIG. . In step c, the high/low speed flag is reset, while in step d, the all speed flag is reset, so that only one of the flags is always set.

In step e, it is determined whether one of the two types of flags mentioned above is set, and if the all-speed flag is set, then in step f, flag 1 in FIG. All-speed governor characteristic calculation corresponding to the function of the target data generation circuit 13 is executed by map calculation, and first target data _D1 is obtained.
On the other hand, if the high/low speed flag is set,
Proceeding to step g, a high-low speed governor characteristic calculation corresponding to the function of the second target data generation circuit 14 shown in FIG. 1 is executed by map calculation, and the second target data is generated.
_D2 is obtained. Then, in step h, one of the data is output, and the process returns to step a.

As can be seen from the above explanation, the set state of each flag is allowed to be changed only when the engine is in an idling state, and the engine 2 has high/low speed governor characteristics or all speed governor characteristics according to the set state of the flags. The operation is controlled, and the same effect as shown in FIG. 1 can be obtained.

In the above embodiments, the governor characteristics can be changed only when the engine is in an idling state, but the present invention is not limited to these embodiments, and the governor characteristics can be changed only when the engine is in an idling state. An appropriate condition other than the idling operating state may be given as the condition that allows the characteristics to be changed.

Figure 5 shows the conditions that allow changing the governor characteristics.
An example of a program is shown in which the initialization state immediately after the power is turned on instead of the idle operating state is used. The flowchart shown in FIG. 5 is executed by a microcomputer instead of the flowchart shown in FIG. 4, and after the system is initialized at step i in response to turning on the power, Immediately, the state of the switch 18 is determined (step b), and thereafter, the governor characteristics are switched in the same steps as shown in FIG. 4, and the required data is output. Steps b to h in FIG. 5 are steps b to h shown in FIG.
Since they are the same as h to h, detailed explanation will be omitted.

If the program shown in FIG. 5 is followed, the governor characteristics can be switched only before the engine starts, and the governor characteristics can be switched even more safely.

According to the present invention, as described above, the configuration is such that the characteristics can be switched between the all-speed governor characteristic and the high-low speed governor characteristic only under predetermined conditions. It is possible to provide a highly safe electronic governor for an internal combustion engine that can reliably prevent malfunctions such as sudden changes in engine speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of an embodiment of the present invention, FIG. 2 is a circuit block diagram showing the control system of the device shown in FIG. 1, and FIG. 3 is a block diagram showing the operation of the control system shown in FIG. FIG. 4 is a flowchart of a program when the control data generation circuit shown in FIG. 1 is configured by a microcomputer, and FIG. 5 is a diagram showing a modification of the program shown in FIG. 4. This is a flowchart of the program. 1...Fuel injection pump, 2...Internal combustion engine, 5...
... Control sleeve, 7 ... Electromagnetic actuator, 8 ... Control unit, 9 ... Sensor coil, 10 ... Position detection circuit, 11 ... Rotation speed detector, 12 ... Accelerator detector, 13 ... First target Data generation circuit, 14... Second target data generation circuit, 15... Discrimination circuit, 16... Changeover switch, 18... Switch, 20... Control data generation circuit, D ₁ ... First target data, D ₂ ...Second target data, _D0 ...Target injection amount data, A...Accelerator signal, N...Speed signal.

Claims (1)

[Claims] 1. In an electronic governor for an internal combustion engine in which an actuator for adjusting the injection amount of a fuel injection pump for an internal combustion engine is driven in response to an electrical signal indicating operating conditions of the internal combustion engine, all-speed characteristic control is performed in response to the electrical signal. means for outputting a first signal for
a second one for controlling high and low speed characteristics in response to the electric signal;
a means for outputting a signal; a determining means for determining whether the internal combustion engine is in a predetermined switchable operating state; a specifying means for specifying either the first signal or the first signal; Therefore, selecting means selects either the first signal or the second signal according to the specifying means when it is detected that the predetermined switchable operating state is present; an electronic governor for an internal combustion engine, comprising means for driving the actuator in response to a signal.