JP3202153B2 - Electronic governor type low noise tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for reducing engine noise generated when there is no load in a tractor of the type in which an engine speed is controlled by an electronic governor.

[0002]

2. Description of the Related Art Conventionally, in a tractor, it has been proposed that the vehicle be actually open.
As shown in 5-46007, it is required to travel at a substantially constant speed that is efficient for the work in accordance with various works. Therefore, it is desired that the engine speed be kept constant. On the other hand, the load fluctuates greatly during work, especially when high-speed work is performed, and in such a situation, control for maintaining the engine speed is desired. As described above, a tractor equipped with a diesel engine has conventionally been provided with a governor, i.e., a governing mechanism, as a structure for maintaining the engine speed, which includes a mechanical governor and an electronic governor. . In both cases, the position of an actuator for adjusting the fuel injection amount in the fuel injection pump is controlled, but the former is controlled by the movement of a governor weight attached to a plunger drive cam shaft of the fuel injection pump synchronized with the engine speed. In contrast to driving an actuator, the latter controls a solenoid valve or the like by a control signal based on detection of an accelerator position and an engine speed, for example, as disclosed in Japanese Patent Application Laid-Open No. 6-141606, and drives the actuator. You do it.

[0003] Due to such a structural difference, in the mechanical governor, the engine speed necessarily varies with the adjustment of the fuel injection amount to adjust the output in response to the load variation. That is, the horsepower curve with respect to the engine speed is a droop curve as shown in FIG. In this regard, in the case of the electronic governor control, it is possible to adjust the output by adjusting the fuel injection amount while maintaining the engine speed with respect to load fluctuation (isochronous control). Also,
Conversely, droop control that varies the number of revolutions in accordance with the adjustment of the fuel injection amount is also possible. For these reasons, tractors having an engine control mechanism using an electronic governor have been increasing in recent years, particularly when high-speed work is required.

[0004]

The working speed of the tractor is set as the rated speed at which the engine produces the maximum output. In this situation, if the tractor working at the rated speed suddenly goes into a non-working state,
No load is applied, and the governor attempts to reduce and adjust the fuel injection amount to maintain the rotation speed. In the case of a mechanical governor, due to the structure as described above, the engine speed also increases as the fuel injection amount decreases, and when the engine reaches the no-load maximum speed, the engine speed is considerably higher than the rated speed. Due to the number, there is a problem that the gear pump and the engine emit extremely high noise. In the case of an electronic governor, as described above, there is a degree of freedom in controlling the number of revolutions associated with the adjustment of the fuel injection amount, and in particular, since isochronous control is possible, the electronic governor can be used to control the rating of such an engine in a no-load state. It is an object to reduce high noise in a no-load state where the rotation speed is higher than the rotation speed.

[0005]

The present invention uses the following means in order to solve the above-mentioned problems. The engine that sets the rated speed to the maximum output speed
Equipped with a gin, the engine speed is controlled by an electronic governor
For tractors that can be controlled,
Tillage control of a rotary tiller
Tillage control based on detection of rear cover sensor CS of device R
If the rear cover sensor CS does not work,
That is, when the rear cover Ra is located in the dead zone
Only to perform load tillage control based on engine load detection
In the configuration, when there is no load at the rated speed
The maximum rotation speed is increased by a certain rotation speed from the rated rotation speed.
Speed, and reduce engine noise generated when there is no load.
It is a well-constructed one.

[0006]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view of a tractor, FIG. 2 is a block diagram of an engine control and tillage depth control mechanism of an electronic governor, FIG. 3 is an engine control block diagram of an electronic governor mechanism,
FIG. 4 is a graph showing a horsepower curve and a torque curve with respect to the engine speed by the electronic governor control when the maximum no-load speed and the rated speed are matched, and FIG. 5 is a diagram showing the engine with respect to the accelerator sensor value corresponding to the case of FIG. FIG. 6 is a flow chart showing rack control of the electronic governor corresponding to the case of FIG. 4, and FIG. 7 is an electronic governor control in the case where the maximum no-load rotational speed is set at a fixed value higher than the rated rotational speed. FIG. 8 is a graph showing the displacement of the engine speed with respect to the accelerator sensor value corresponding to the case of FIG. 7, and FIG. 9 is the electronic governor also corresponding to the case of FIG. FIG. 10 is a graph showing a horsepower curve and a torque curve with respect to the engine speed by the mechanical governor control. That.

As shown in FIG. 1, in a tractor, an engine E is provided in a bonnet 1 and a fuel injection pump P is attached to the engine E. The fuel injection pump P is provided with an engine speed sensor ES and a rack position sensor RS. In the front column 2 behind the hood 1, an accelerator lever AL is provided, and an accelerator sensor AS for detecting the amount of tilting of the lever is provided inside the front column 2. An engine control controller EC that issues an engine control signal based on the detection values of these sensors is provided at the front end of the hood 1.

Next, the arrangement and linkage structure of each part for controlling the tillage depth will be described with reference to FIGS. At the rear of the tractor, a hydraulic lift L which is raised and lowered by electromagnetic valve control is projected rearward, and pulls a working machine such as a rotary tilling device R shown in FIG. As a controller for transmitting a control signal to this electromagnetic valve to control the lifting and lowering of the hydraulic lift L, a hydraulic lift controller LC is installed in the tractor body beside the driver's seat separately from the engine control controller EC. ing. In addition to the electromagnetic valve for raising and lowering the hydraulic lift L, an electromagnetic valve for controlling the left-right inclination of the hydraulic lift L is also provided, and this can be used to control the working machine horizontally. This is also controlled by the hydraulic lift controller LC, and therefore, the hydraulic lift controller LC can perform lifting / lowering control and horizontal control of the working machine.

[0009] In addition to the plowing depth control according to the present invention, the lifting mode is controlled by raising the work implement during turning (turning on the turning mode switch SW4, this control is performed). There is a control to raise the work implement during reverse movement (this control is performed when the back switch SW5 is turned on). As an input means in the reverse control according to the present invention, first, a tillage setting dial D for setting a tillage depth is provided.

[0010] As a detecting means relating to the tillage depth control,
Lift angle sensor LS for detecting the angle of hydraulic lift L
Is provided in the vicinity of the rotation axis of the hydraulic lift L, and the rear cover Ra of the rotary tilling device R is provided with detection means synchronized with the inclination of the rear cover Ra, and detects the movement of this detection means. Cover sensor CS that detects the inclination angle of the rear cover Ra
Is provided at the rear inside the tractor body.

Further, a position sensor PS for detecting the height of the rotary in the rotary tiller R, that is, the actual tillage depth, is provided in the tractor body. In connection with the detecting means provided, the tillage depth can be detected. And in the tillage depth control of the present embodiment,
Assuming that the rear cover sensor CS does not work, a plowing depth control mechanism based on engine load detection is provided.

That is, an accelerator sensor AS which is a sensor for detecting an electronic governor, an engine speed sensor ES, a rack position sensor RS, and a hydraulic lift angle sensor L
This is a plowing depth control in which the lift of the hydraulic lift L is controlled by using S as a detection unit. In order to select to perform the tillage depth control (load tillage depth control) by the electronic governor, a load tillage depth control setting switch SW2 is provided, and the tillage depth control based on the detection of the rear cover sensor CS is provided. In order to select the load tillage depth control only when the rear cover Ra is located in the area where the rear cover sensor CS does not work, that is, when the rear cover Ra is located in the dead zone, the mix tillage depth control SW is selected.
3 are provided.

As described above, although the plowing depth control mechanism using the electronic governor is provided, as shown in FIGS. 1 and 2, the engine control controller EC and the hydraulic lift controller LS are separate. When a failure occurs in the control mechanism related to the hydraulic lift system, only the hydraulic lift controller LC needs to be replaced, and the failure does not affect the engine control system. Also,
Conversely, even if a failure occurs in the engine control system, the hydraulic lift controller LC can be left as it is. That is, one of the failures does not reach one side between the engine control system and the hydraulic lift control system, thereby contributing to improvement in maintenance and cost reduction.

Thus, the engine controller E
In a configuration in which C and the hydraulic lift controller LC are separated, control signals transmitted from the engine control controller EC to the hydraulic lift controller LC include electronic governor detection means (accelerator sensor AS, engine The load ratio (the ratio of the actual engine speed to the set speed detected by the accelerator sensor AS) V _L obtained from the speed sensor ES and the rack position sensor RS is transmitted as a load factor signal. It is used for the plowing depth control according to the present embodiment.

In addition to the plowing depth control, the traveling along with the raising and lowering of the hydraulic lift L, such as the deceleration at the time of turning, the deceleration at the plowing depth, or the speed control in accordance with the operation of the hydraulic lifting switch SW1. It is adapted to control the speed, and hydraulic lift pivot from the control controller LS signal S _S, back signal S _B also, the engine rotational speed change signal S _UD and the like based on the operation of the hydraulic lift switch SW1 is transmitted .

Next, the electronic governor mechanism will be described with reference to FIGS. The electronic governor is provided with an actuator section for slidingly driving a rack 11 for adjusting a fuel suction amount of a plunger in a fuel injection pump P by a solenoid S (or a motor M). A control signal. The input means includes an engine speed sensor ES for detecting the rotation speed of the camshaft synchronized with the engine speed, an accelerator sensor AS, and a rack position sensor RS for detecting the rack position. The control signal is issued based on the detection signals of these input means.

When the load fluctuates, what kind of fuel injection amount is used and what kind of engine speed is determined by the setting of the arithmetic circuit of the engine control controller EC.
Isochronous control can be used to adjust the fuel injection amount so that the rotation speed is kept constant even when the load fluctuates, and droop that adjusts the output to reduce the rotation speed to some extent when the load increases. Control can also be used.

Under these circumstances, in FIG. 4, when no load is applied at the rated engine speed FR,
Isochronous control for reducing the output to maintain the rated rotational speed FR is adopted. The solid line F is the maximum horsepower in each engine rotational speed N _E, a broken line F 'shows the variation in horsepower due to load fluctuation at rated speed FR. That is, as can be seen from the broken line F ', when there is a load change at the rated rotational speed FR, for example, when the load state is changed to no load, the horsepower, that is, the fuel injection amount, is maintained while the rated rotational speed FR is maintained. Can be adjusted.

Although T is a torque curve, in the case of electronic governor control, it is possible to extract a sufficient torque in the entire rotation speed range. In the case of FIG. 4, the engine speed _NE does not change at all in the non-working state, that is, when there is no load in a state where the work is being performed at the rated speed FR that generates the maximum output as the work output. Speed is kept constant,
The noise generated by the high engine speed is not generated. In addition, the graph of FIG. 5 shows the displacement of the engine rotation set value N _ES set by the accelerator sensor AS value. The accelerator sensor AS value is set to the maximum value MAX, and the engine speed is set to the rated speed FR. ing.

FIG. 6, corresponding to FIGS. 4 and 5, is a control flowchart relating to the rack position operation when the no-load maximum rotation speed MR is equal to or approximately equal to the rated rotation speed FR. That is, when the maximum value MAX of the accelerator sensor AS value, the engine speed N _E is the rated speed FR or approximations thereof, the maximum value MAX accelerator sensor AS value
Except when the is to match the engine speed N _E to the engine rotation set value N _ES to be set based on the accelerator sensor AS values, rack operation. Note that N _IDLE indicates the idle speed, and IDLE indicates that the accelerator sensor AS value is the idle set value.

In the case of FIG. 7, the no-load maximum rotational speed MR which becomes zero when the maximum output is generated at the rated rotational speed FR and the load is changed to the no-load state is smaller than the rated rotational speed FR. The rotational speed is set to be slightly higher (FR + ΔR). In the case of FIG. 4, although it is excellent in terms of noise reduction, since the maximum rotation speed and the rated rotation speed FR match,
If a load equal to or greater than the maximum load is applied while working at the rated rotational speed FR, the rotational speed falls immediately and the vehicle suddenly decelerates, making it difficult to drive.

In this regard, as shown in FIG. 7, if the no-load rotational speed MR is set at a position higher than the rated rotational speed FR by a constant rotational speed ΔR (about 50 rpm), for example, in the state of the no-load maximum rotational speed MR, When the load is applied and the maximum horsepower is reached, the rotational speed gradually decreases by ΔR and approaches the rated rotational speed FR, so that no sudden deceleration occurs, and It is possible to confirm that the load has been applied from the load state by moderate deceleration.
It is easier to drive than by the control of.
Further, ΔR is small, and there is not much difference between the no-load maximum rotation speed MR and the rated rotation speed FR. Therefore, the noise does not become so large even at the maximum no-load rotation speed MR. The goal of reducing noise has been fulfilled.

The graph of FIG. 8 shows the displacement of the engine rotation set value N _ES set by the accelerator sensor AS value, and the accelerator sensor AS value is set to the maximum value MA.
When X is reached, the engine speed is set to be higher by ΔR than the rated speed FR. FIG. 9 shows FIG.
10 is a control flowchart relating to rack position operation when the no-load maximum rotation speed MR is set to a rotation speed ΔR higher than the rated rotation speed FR, corresponding to FIG. That is, when the maximum value MAX of the accelerator sensor AS value is for the engine rotational speed N _E and FR + ΔR (= MR), except when the accelerator sensor AS value of the maximum value MAX is accelerator sensor AS value Engine set value N _ES set based on
In order to match the engine speed N _E, rack operation.

As described above, by controlling the fuel injection amount in accordance with the load fluctuation between the rated speed and the no-load speed by the electronic governor, the engine noise at the time of no load which cannot be fulfilled by the mechanical governor can be reduced. Can be realized. Here, the engine control by the mechanical governor will be described with reference to FIG. First, the torque T suddenly decreases as the rotational speed increases from the rated rotational speed FR at which the maximum horsepower is generated. When the load is reduced from the state where the maximum horsepower is generated at the rated rotational speed FR, the torque T is indicated by a broken line. As described above, the horsepower is reduced while the rotation speed is gradually increased, that is, the fuel injection amount is reduced.

Finally, the no-load maximum rotational speed MR is finally obtained. In this case, the rotational speed difference ΔR ′ between the no-load maximum rotational speed MR and the rated rotational speed FR is considerably large (FIG. 7).
ΔR ′> ΔR), the engine and the gear pump set at the rated rotation speed generate very loud noise at this rotation speed. The electrifying governor control described with reference to FIGS. 4 to 9 can solve this problem and provide a low-noise tractor.

[0026]

As described above, the present invention has the following advantages. The load fluctuations from the rated rotation speed are configured so as to accompany a slight increase in the rotation speed.However, when approaching the maximum horsepower from the no-load state to the load state, the rotation speed gradually decreases and the maximum It becomes the number of revolutions that generate horsepower, and the driver can perceive that a load has been applied, not a sudden deceleration, but a moderate deceleration, making driving easier . On the other hand, in the case of no load from the rated speed, the no-load maximum speed is not set to a significantly higher speed than the rated speed, so the noise is not so high even if the no-load maximum speed is reached. Rather, it is in line with the intent to provide low-noise tractors.

[Brief description of the drawings]

FIG. 1 is a plan view of a tractor.

FIG. 2 is a block diagram of an electronic governor engine control and plowing depth control mechanism.

FIG. 3 is an engine control block diagram of the electronic governor mechanism.

FIG. 4 is a graph showing a horsepower curve and a torque curve with respect to an engine speed by electronic governor control when the maximum no-load speed and the rated speed are matched.

FIG. 5 is a graph showing a change in engine speed with respect to an accelerator sensor value corresponding to the case of FIG. 4;

FIG. 6 is a rack control flowchart of the electronic governor corresponding to the case of FIG. 4;

FIG. 7 is a graph showing a maximum horsepower curve and a torque curve with respect to the engine speed by the electronic governor control when the no-load maximum speed is set to be a fixed number higher than the rated speed.

8 is a graph showing a change in engine speed with respect to an accelerator sensor value corresponding to the case of FIG. 7;

9 is a rack control flowchart of the electronic governor corresponding to the case of FIG. 7;

FIG. 10 is a graph showing a horsepower curve and a torque curve with respect to the engine speed under the mechanical governor control.

[Explanation of symbols]

E Engine P Fuel injection pump R Rotary tillage device S Solenoid ES Engine speed sensor AS Accel sensor RS Rack position sensor L Hydraulic lift Ra Rear cover EC Engine control controller LC Hydraulic lift controller CS Rear cover sensor D Tillage setting dial SW2 Load tillage control switch SW3 mix Kofuka control switch N _E engine speed (rpm) MR unloaded maximum speed (rpm) FR rated speed (rpm) engine speed setting value set by N _ES accelerator sensor aS (rpm) [Delta] R constant rotational speed 11 racks

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI F02D 41/04 380 F02D 41/04 380C // F02D 9/02 331 9/02 331D (58) Fields surveyed (Int. Cl. ⁷ , DB name) F02D 29/00-29/06 A01B 63/111 F02D 1/02 F02D 41/04

Claims (1)

(57) [Claims] (1) A rotation speed at which a maximum output is generated is defined as a rated rotation speed.
Electronic engine that controls the number of revolutions of the engine.
Tractor that can be controlled by
The tillage depth control of the rotary tiller attached to the
Based on the detection of the rear cover sensor CS of the Lee tiller R
Is the rear cover sensor CS working together with the till depth control?
The rear cover Ra is located in the dead zone.
Only when it stops, the load depth control based on engine load detection
No load at the rated speed
The maximum number of rotations in the case of
High engine speed and reduce engine noise generated when there is no load.
An electronic governor-type low-noise tractor, characterized in that it is configured to reduce the noise.