JPS60256529A - Control device in internal combustion engine - Google Patents

Abstract

PURPOSE:To enhance the feeling of operation, by selecting one of a plurality of speed variation rate characteristics which show the required relationship between a set value of the rotational speed of an engine and an actual value of the engine rotational speed in association with variations in load, necessarily in accordance with the content of working. CONSTITUTION:In a Diesel-engine, a rack actuator 3 controls the amount of fuel injection from a fuel injection pump 2, and a timer actuator 4 controls the timing of fuel injection, and a control section 20 controls the actuators 3, 4. In this arrangement, the control section 20 is provided with a data ROM25 storing therein set values of the rotational speed of the engine which are set in accordance with the position of an accelerator 9 and speed variation rate characteristics which indicate the trends of the actual rotational speed of the engine in accordance with loads which are prepared for each of working operations having different required speed variation rate characteristics. Further, a desired fuel supply amount is determined in accordance with a speed variation rate characteristic in accordance with the operation of a mode selecting switch 27 to control the rack actuator 3.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a control device for an internal combustion engine that changes the speed fluctuation rate of the internal combustion engine according to the content of work.

,, <Prior Art> In agricultural machinery, construction machinery, etc., it is common practice to use the same working machine for various types of work by attaching various peripheral devices. In this case, the work styles are diverse and the speed fluctuation rates required of the engine are often not the same. For example, in a tractor, sudden accelerator operation is performed when driving on the road or when working with a front loader, smooth acceleration and deceleration is required when driving on a road, and sudden loads are required when driving on a road. Due to the added fluctuations, different speed fluctuation rate characteristics are required depending on each work, while rotary and plow.

In the case of plowing work such as digging potatoes, constant speed, constant plowing depth, constant movement speed, etc. are required, so constant speed characteristics are required.

However, conventional mechanical or electronically controlled governors
Generally, so-called all-speed governors have a moderate speed fluctuation rate, and the speed fluctuation rate is constant and cannot be changed freely. However, the operating feeling, work efficiency, fuel efficiency, etc. had to be sacrificed to some extent.

<Problems to be Solved by the Invention> The present invention focuses on the above-mentioned problems and makes it possible to switch the speed fluctuation rate characteristics according to the purpose of the work. The object of this invention is to provide a control device for an internal combustion engine that can improve operational feeling and workability.

<Means for Solving the Problems> In order to achieve the above object, the present invention includes an engine speed detecting means for detecting the actual value of the engine speed, and a set value of the engine speed based on the accelerator position. A memory that stores the possible relationship between the accelerator position detection means to be detected, the set value of the engine speed, and the actual value of the engine speed due to load fluctuation, for each of a plurality of speed fluctuation rate characteristics that differ depending on the work content. means, characteristic selection means for arbitrarily selecting a predetermined speed fluctuation rate characteristic from the plurality of speed fluctuation rate characteristics, and a characteristic selection means for arbitrarily selecting a predetermined speed fluctuation rate characteristic from the plurality of speed fluctuation rate characteristics; The present invention is characterized by comprising a calculation means for determining a target fuel supply amount for obtaining a value and outputting a control output, and a fuel control means for adjusting the fuel supply amount based on the control output of the one calculation means.

<Operation> The internal combustion engine control device of the present invention is configured as described above, and by selecting the speed fluctuation rate characteristic according to the content of one work using the characteristic selection means, the engine can be adapted to various uses. This allows the same work equipment to be used for a wide range of tasks without any problems.

<Example> Hereinafter, the present invention will be specifically described with reference to an example relating to control of the illustrated diesel engine.

In the conceptual system diagram in Figure 1, (1) is the engine, (2) is the fuel injection pump, (3) is the rack actuator, (
4) is the timer actuator, (5) (6) is the position sensor for each actuator, (7) is the rotation speed sensor,
(8) is an accelerator position sensor, and (9) is an accelerator.

The engine output and torque of the engine (1) are determined by the injection amount and injection timing of the fuel injection pump (2) and the engine rotation speed. The fuel injection amount is adjusted by moving a fuel rank (not shown in FIG. 1) via an injection amount adjustment lever (10) by an actuator (3) using a linear solenoid, stepping motor, or the like. Injection timing is also adjusted by changing the prestroke and cam phase.

These changes can be made mechanically or hydraulically, using actuators (such as linear solenoids, stepping motors, solenoid valves, etc.) via the timing adjustment lever (11).
4). The engine speed is detected, for example, by detecting the movement of a groove (13) in a magnetic rotating body (12) attached to a camshaft with a rotation speed sensor (7) consisting of an electromagnetic pickup, and also by detecting the amount of fuel injection. By measuring the injection amount based on the rack position and engine speed in advance, the operating position of the actuator (3) can be detected by a position sensor (5) such as a differential transformer, and the engine speed can be detected at the same time. You can know by (]4) indicates a nozzle.

(20) is a control unit, which controls the operating state of the engine according to instructions from the operator. A microcomputer is used as this control unit, and the A/V of various input/output signals is
I10 control ROM (21) that performs D and D/A conversion, pulse counting, conversion to pulse output, etc., CPU (22) that provides control calculations and input/output instructions, and CPII (22).
) used for control calculations (23), a program ROM (24) that stores control programs, and a data ROM (25) that stores various data necessary for control calculations such as speed fluctuation characteristics described later. It is made up of etc.

FIG. 2 shows an example of a specific configuration of the governor section including the above-mentioned rack actuator (3), etc.
A linear solenoid type rack actuator (3) is connected to one end of a fuel rack (32) protruding into the governor case (31) of the fuel injection pump (2) via a connecting portion (33).
) and a differential transformer type position sensor (5) are coaxially connected, and a magnetic rotating body (12) is attached to the camshaft (34), and a plurality of concave grooves ( 13) is formed. The actuator (3) has an actuation coil (
35), a fixed core (36), a movable core (38) attached to a shaft (37), etc., and a position sensor (5)
consists of a detection coil (39) consisting of a plurality of coils, a movable bore (40) attached to a shaft (37), etc. The rotation speed sensor (7) is an electromagnetic pickup and is close to the magnetic rotating body (12)! placed in a concave groove (
13) The number of rotations is detected from the number of changes in magnetism as the magnetic field passes through.

The data ROM (25) contains the set value of the engine speed, which is arbitrarily set by the position of the accelerator operated by the operator's own will, and the speed that shows how the actual speed (actual value) changes depending on the load. The variation rate characteristics are stored in the form of arithmetic expressions or numerical tables for each work content that requires different speed variation rate characteristics. The case of the numerical table will be explained below. Table 1 is an example of the i-th numerical table (hereinafter referred to as droop rate map), where the set value N5et and the actual value Na
Di at the intersection of ct indicates the droop coefficient in each case.

In addition, b at no load corresponding to the set value N5et
l The no-load equivalent rack position map shown in Table 2 which defines the relationship between the idling speed N1dl and the rack position relative to this, that is, the no-load equivalent rack position [Ridl], and the no-load equivalent rack position map determined to limit the maximum injection amount at each rotation speed. The maximum rack position map shown in Table 3 is also stored in the data ROM.
(25).

Note that Nj and dl in Table 2 above are N set,
Furthermore, even if Nmax in Table 3 is replaced with N'act, they are substantially the same.

As mentioned above, the droop rate map is created for each of a plurality of control modes having different speed fluctuation rate characteristics, but for the sake of simplifying the explanation below.

i=1 and i=2. That is, a case will be described in which two maps, control mode 1 and control mode 2, are used. In Fig. 1, (27) is a mode selection switch for selecting a predetermined one from among these multiple modes, and the 1 selection instruction is recognized by the on/off state of the switch and executed by logical judgment on the control program. It has the ability to always select one mode.

FIG. 3 shows an example of the relationship between engine speed, rack position, and engine shaft output based on these maps, and intermediate values not shown in the table can be determined by interpolation. In FIG. 3, A and A2 are the characteristics according to Tables 1 and 2, respectively, and show an example where control mode 2 shown by a broken line has a larger speed fluctuation rate. Further, B indicates the rack position corresponding to no load according to Table 2, and C indicates the maximum rack position according to Table 3.

Further, other control data such as timing characteristics for determining injection timing are also stored in the data ROM (25), but since they have no direct bearing on the present invention, their explanation will be omitted.

Next, the operation will be explained with reference to the control flowchart shown in FIG.

Various signals for recognizing engine status are controlled by I10 control R.
It is managed by the OM (21), converted into a recognizable signal, and input to the CI"U (22). Then, the CPII (22
) performs control calculations according to a predetermined program and outputs various control signals.

Regarding the speed fluctuation rate, as shown in Fig. 4, first the set value N set and actual value N act of the engine speed are recognized, and the no-load equivalent rack position Ridl is read from Table 2, and then the mode set by the operator is Selection switch (
27) and calculates the target rack position Rset to be set using the droop rate map of i=1 or i=2 depending on the mode.

This target rack position [Rset is the set value N of the engine speed
In order to obtain a predetermined actual value Nact for 5et, the detected N
Using the loop coefficient D1 determined from Table 1 from set and Nact and Table 2, the following calculation formula Rset,
= (Nset - Nact)X Di+ Ridl.

Next, calculate the maximum rack position Rmax from Table 3 and compare it with the Rset you just found, and if Rset > Rmax
Otherwise, a control signal for setting the actual rack position Racj to Rset is output from the CPU (22) to the rack actuator (3), and R set )
If Rmax, the CPU (22) sends a control signal to correct Rset=Rmax so that the rotational speed does not exceed the allowable value, and to set the actual rack position Ract to the corrected target rack position Rset. It is output to the rack actuator (3). In this way, the rack position of the fuel pump (2) is automatically adjusted, and operation is performed at a predetermined speed fluctuation rate.

The plurality of speed fluctuation rate characteristics in the above embodiments are selected depending on the content of the work, and one of them can be a constant speed characteristic corresponding to work requiring constant speed operation.

Figure 5 shows each map of the embodiment in such a case. Ah91. :os"c't d l□Mode 2 has a constant speed characteristic. In this way, when one of the control modes is set to a constant speed characteristic, one of the maps shown in Table 1 above is changed to a speed fluctuation characteristic. Although it is possible to use a constant velocity characteristic without a constant velocity characteristic, an example using a correction coefficient N5ift will be described here.

FIG. 6 shows the control mode selection procedure,
Constant speed control is based on the assumption that the operator is not operating the accelerator, so when the mode selection switch (27) is set to mode 2, it is first checked whether the accelerator is fixed, and the accelerator is fixed. mode 2 is selected only when the accelerator is being operated, and mode 1 droop control is selected regardless of the mode selection switch (27) if the accelerator is being accelerated or decelerated.

When mode 2 is selected, the set value Nset and the actual value Nac7 are first compared as shown in FIG.

The correction set value N5et' is determined by the following arithmetic expression %. The correction coefficient N5if is a value set in advance through preliminary experiments depending on the structure and rating of the engine. Next, the target rack position Rset is calculated in the same manner as in FIG. 4, but when N5et' is determined, this N5et' is used instead of the set value Nset set by the accelerator.

In this way, the rack is moved to the target rack position based on the corrected setting value, and constant speed control is performed.

Although the above embodiments are for a diesel engine, the control according to the present invention can be similarly implemented for, for example, a gasoline engine by making modifications according to the type of engine. In this case, the throttle opening corresponds to the rack position in the embodiment.

<Effects of the Invention> As is clear from the description of the embodiments above, the present invention allows the speed fluctuation rate characteristic to be arbitrarily selected depending on the work content and the engine to be operated in an appropriate state at all times. In addition to improving the operating feel of the machine and improving work efficiency, it is also relatively easy to correctly judge the load situation from the operating noise, which prevents forcing the machine to operate unreasonably, which has a negative impact on fuel efficiency and engine life. This has the effect of reducing the possibility of such occurrences and allowing one working machine to operate more efficiently.

[Brief explanation of drawings]

Figures 1 to 4 show one embodiment of the present invention.
The figure is a conceptual system diagram, Figures 2 (a) and (b) are partially cutaway side views and front and front views illustrating the configuration of the governor section, and Figure 3 is a diagram showing the position and output of the engine entrance rotation. A characteristic diagram showing the relationship, and FIG. 4 is a control flowchart. Figures 5 to 7
The figures show other embodiments, FIG. 5 is a characteristic diagram, and FIGS. 6 and 7 are control flow charts. (1)... Engine, (2)... Fuel injection pump, (3
)... Rack actuator, (7)... Rotation speed sensor, (8)... Accelerator position sensor, (9)...
Accelerator, (20)...control unit, (22)...cp
υ, (25)...Data ROM, (27)...Mode selection switch Patent applicant Yanmar Diesel Co., Ltd. Agent
Patent Attorney Shino 1) Actual Figure 1 Figure 3 En;

Claims (2)

[Claims] (1) An engine speed detection means for detecting the actual value of the engine speed; an accelerator position detection means for detecting the set value of the engine speed based on the accelerator position; and an engine speed detection means for detecting the set value of the engine speed based on the accelerator position; a storage means for storing a possible relationship with an actual value of the number for each of a plurality of speed fluctuation rate characteristics that differ depending on the work content, and arbitrarily selecting a predetermined speed fluctuation rate characteristic from the plurality of speed fluctuation rate characteristics. and a characteristic selection means for. a calculation means for determining a target fuel supply amount to obtain a predetermined actual value corresponding to a set value of the engine speed based on the selected speed fluctuation rate characteristic and outputting a control output; and a control output of the calculation means. A control device for an internal combustion engine, comprising: a fuel control means for adjusting a fuel supply amount; (2) The control device for an internal combustion engine according to claim 1, wherein one of the plurality of speed fluctuation rate characteristics that differ depending on the work content is a constant speed characteristic without speed fluctuation.