JP2008274913A - Method for adjusting engine characteristics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for adjusting engine characteristics easily reducing individual difference of background noise of machine bodies. <P>SOLUTION: Background noise value of the machine body is measured by a noise meter and is defined as a background noise measured value. If the background noise measured value is not less than noise regulation value, the background noise measured value is input to a controller from a monitor. The controller determines whether load of an engine is in a light load zone or in a heavy load zone, based on load zone determination signal detected by a load determination signal detection means. If engine load is in the light load zone, the controller automatically adjusts an engine accelerator value in the light load zone to noise adjustment accelerator position to provide engine rotation speed for keeping background noise measurement value not greater than noise regulation value from set accelerator position set by an accelerator position setting apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine characteristic adjustment method that reduces individual differences in ambient noise of a fuselage.

  In construction machinery, the engine rotational speed (hereinafter referred to as “rotational speed”) is detected, and the ambient noise level measured before the engine is started is compared with the total noise level measured after the engine is started. When the noise level is higher than the ambient noise level, the lowest engine speed (higher than the idle speed, for example, about 1500 rpm) stored in the storage unit is output to the control means, and the total noise level is output. There is a noise suppression device in a construction machine that reduces the noise that the construction machine gives to the surrounding environment as close as possible to the ambient noise level (see, for example, Patent Document 1).

  The noise suppression device for a construction machine disclosed in Patent Document 1 can reduce ambient noise by suppressing the engine speed and also reduce the engine output, so that the required engine output may not be obtained. .

That is, the engine speed-output characteristics in the mode in which the maximum output and the maximum speed to be measured at the time of ambient noise measurement are generally 100% shown by the solid line in FIG. To reduce ambient noise from among multiple engine speed-output characteristics indicated by multiple straight lines, using an accelerator position setter (so-called accelerator dial) that allows the engine speed to be selected from multiple levels of accelerator position. If a low accelerator position such as 80% or 70% is simply selected, the rated output cannot be obtained. As engine characteristics that can be controlled by the governor, a plus droop characteristic in which the engine speed decreases as the power increases is common, and the load fluctuates during actual work. The engine speed changes.
Japanese Patent Laying-Open No. 2004-301028 (first page, FIG. 1)

  As described above, when the engine speed is adjusted by the accelerator position setting device, the rated output cannot be generated. Therefore, the ambient noise cannot be adjusted only by the accelerator position setting device. Therefore, as shown in FIG. 8, it is necessary to design the aircraft with a large margin with respect to the noise regulation value so that the ambient noise value does not exceed the noise regulation value.

  That is, the ambient noise (acoustic power level), which is a standard for obtaining certification of the low noise construction machine and the ultra low noise construction machine of the Ministry of Land, Infrastructure, Transport and Tourism, varies to some extent due to individual differences in the aircraft. Therefore, at present, considering the variation, it is necessary to design with a margin so that the largest noise value satisfies the noise regulation value.

  For example, in the example shown in FIG. 8, a margin of 0.5 dB is taken as an average value with respect to the noise regulation value, but it is not easy to secure such a large margin in the aircraft design. There are problems such as high costs for reduction measures.

  The present invention has been made in view of these points, and an object of the present invention is to provide an engine characteristic adjustment method that can easily reduce individual differences in ambient noise due to the aircraft.

  The invention described in claim 1 measures the ambient noise value of the aircraft equipped with the engine, and in the case of the aircraft whose ambient noise value exceeds the noise regulation value, the engine load is in a low load range. This is an engine characteristic adjustment method in which the engine output characteristic curve is changed and adjusted to the engine speed reduction side according to the ambient noise value.

  The invention described in claim 2 is a method of changing and adjusting the engine accelerator value in the low load range according to the ambient noise value as the change adjustment of the engine output characteristic curve in the engine characteristic adjusting method according to claim 1.

  The invention described in claim 3 is a method of changing and adjusting the slope of the droop curve according to the ambient noise value as the adjustment adjustment of the engine output characteristic curve in the engine characteristic adjusting method according to claim 1.

  According to the first aspect of the present invention, the required sufficient engine power can be obtained without affecting the rated output in the high load range, and the engine output characteristic curve in the low load range. By adjusting the engine to the engine speed reduction side according to the ambient noise value, the engine noise can be reduced and the ambient noise can be reduced while suppressing the effect on the machine performance. It is not necessary to take a large margin in the airframe design so as to cope with it, the margin for the noise regulation value can be reduced, and individual differences in ambient noise due to the airframe can be easily reduced.

  According to the second aspect of the present invention, since the engine accelerator value in the low load range is changed and adjusted according to the ambient noise value, the engine noise can be reduced and the ambient noise can be reduced. Individual differences can be easily reduced.

  According to the third aspect of the present invention, by changing and adjusting the slope of the droop curve according to the ambient noise value, the engine speed can be effectively reduced while suppressing the influence on the airframe performance in the low load range. Since ambient noise can be reduced by lowering, individual differences in ambient noise due to the aircraft can be easily reduced.

  Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS. 1 to 5 and another embodiment shown in FIG.

  FIG. 2 shows an outline of an engine accelerator control device. In a construction machine such as a hydraulic excavator, a hydraulic pump that is a hydraulic power source of a hydraulic circuit that operates a hydraulic actuator is connected to an engine 12 mounted on a body 11 as an engine load. Has been. This engine load varies depending on the work situation.

  The engine 12 is provided with a speed control governor 13 such as an electronic governor or a mechanical governor that can be electrically controlled by a control motor, and an engine controller 14 for fuel injection control is connected to the governor 13, The engine controller 14 is connected to a machine controller 15 for calculating a command value of the engine rotation speed (hereinafter referred to as “rotation speed”). The engine controller 14 and the body controller 15 form a controller 16.

  The engine 12 is provided with a speed sensor 17A for detecting the engine speed for fuel injection control and a speed sensor 17B for detecting the engine speed for calculating the engine speed command value. These speed sensors 17A, 17B However, the engine controller 14 and the body controller 15 are connected.

  A monitor 18 installed in the cab of the hydraulic excavator is connected to the controller 16. The monitor 18 is an output device that displays the airframe operating state, and is also an input device that inputs numerical values and the like to the controller 16. The monitor 18 receives a value related to the noise around the machine body, which is measured by the sound level meter 19 and further calculated.

  That is, as shown in FIGS. 3 (a) and 3 (b), the sound level meters 19 are installed at four places around the machine body 11 of the construction machine such as a hydraulic excavator and at two places on the upper side. One ambient noise measurement value is calculated from each measurement value, and the value is input to the monitor 18.

  Returning to FIG. 2, the controller 16 includes an accelerator position setting device 21 such as an accelerator dial for setting a plurality of engine speed-output characteristics with different engine speeds at no load at a plurality of accelerator positions, an engine 12 A load region determination signal detecting means 22 for detecting a load region determination signal for determining whether the load is in a high load region or a low load region is connected.

  As the load region determination signal detection means 22, for example, a pressure sensor that determines the engine load region by detecting the pump discharge pressure of the hydraulic oil discharged from the hydraulic pump driven by the engine 12 is used. In this case, the controller 16 determines that the load of the engine 12 is in the high load region when the pump discharge pressure detected by the pressure sensor or the moving average thereof is equal to or greater than the threshold value.

  The controller 16 detects the set accelerator position set by the accelerator position setting device 21, and based on the load range determination signal detected by the load range determination signal detection means 22, determines whether the load of the engine 12 is in the low load range or high level. If the engine load is in a low load range as shown in FIG. 4, the engine accelerator value to be actually used is set to an accelerator position lower than a set accelerator position, for example, 100%, for example, a reference accelerator position. It has a control function to automatically change to an engine output characteristic curve such as 80% and to return the engine accelerator value to a set accelerator position, for example, an engine output characteristic curve of 100% when the engine load is in a high load range. .

  Further, even if the controller 16 automatically changes the engine accelerator value to a reference accelerator position, for example, an engine output characteristic curve of 80%, the ambient noise measurement value of the airframe 11 measured by the sound level meter 19 becomes equal to or greater than the noise regulation value. In some cases, the engine accelerator value can be changed and adjusted to a plurality of noise adjustment accelerator positions such as 79%, 78%, etc., at which the engine speed at which the ambient noise measurement value does not reach the noise regulation value is obtained. Yes.

  Next, a control example in which the controller 16 changes and adjusts the engine accelerator value on the low load side will be described with reference to the flowchart shown in FIG. 1 and the engine output characteristic curve shown in FIG.

(Step S1)
The ambient noise value of the airframe 11 is measured by a plurality of sound level meters 19 to obtain the ambient noise measurement value.

(Step S2)
It is determined whether or not the ambient noise measurement value is equal to or greater than a target or reference noise regulation value (hereinafter referred to as a reference noise value). If the ambient noise measurement value is not equal to or greater than the reference noise value, there is no need for noise adjustment, and the noise adjustment process is terminated.

(Step S3)
If it is determined in step S2 that the ambient noise measurement value is equal to or greater than the reference noise value, the ambient noise measurement value is input from the monitor 18 to the controller 16.

(Step S4)
For the Aircraft 11 whose ambient noise measurement value exceeds the reference noise value, the controller 16 sets the engine output characteristic curve to the low load side according to the largest ambient noise measurement value on condition that the engine load is in the low load range. Change and adjust the accelerator setting to reduce the engine speed.

  That is, based on the load region determination signal detected from the load region determination signal detection means 22, it is determined whether the load of the engine 12 is in the low load region or the high load region, and the engine load is in the low load region For the purpose of low fuel consumption and low noise, even if the set accelerator position set by the accelerator position setting device 21 is, for example, a 100% engine output characteristic curve shown by a thin solid line in FIG. As in the engine output characteristic curve indicated by the thick two-dot chain line, the engine accelerator value in the low load range is automatically changed to the engine output characteristic curve of the reference accelerator position, for example, 80%. For the aircraft 11 whose measured value exceeds the reference noise value, for the purpose of further noise reduction, as shown in the engine output characteristic curve shown by the thick solid line in FIG. The engine accelerator value in the load range is automatically adjusted to a lower noise adjustment accelerator position, for example, an engine output characteristic curve such as 79%, 78%, etc., and the engine speed in the low load range is lowered to reduce engine noise and engine direct connection fan Try to further reduce the sound.

  Further, when the engine load is in a high load range, as shown in FIG. 4, the rated output can be obtained by returning the engine accelerator value to the engine output characteristic curve of the set accelerator position, for example, 100%.

(Step S5)
Again, the noise level of the airframe 11 is measured by the sound level meter 19.

(Step S6)
Again, determine whether the ambient noise measurement value is equal to or higher than the target or reference standard noise value. If the ambient noise measurement value is not equal to or higher than the reference noise value, no noise adjustment is necessary and the noise adjustment process ends. To do.

(Step S7)
If the ambient noise measurement value is equal to or higher than the reference noise value, it is determined that the noise characteristics of the airframe 11 are abnormal, and the airframe 11 is inspected using a checklist. Thereafter, the process returns to step S1, and the ambient noise value of the body 11 is measured.

  Next, the function and effect of the illustrated embodiment will be described.

  When the set accelerator position set by the accelerator position setter 21 is 100%, for example, when the engine load detected from the load range determination signal detection means 22 is in the high load range, the engine operates at the rated output and is in the low load range. If it is, the vehicle is operated at the reference accelerator position, for example, 80%.

  Since the ambient noise of the airframe 11 measured by the sound level meter 19 is measured in a low load range, in the case of the airframe 11 whose ambient noise value is larger than the reference noise value, the reference accelerator position, for example, 80% is set according to the ambient noise. By adjusting the noise adjustment accelerator position to 79% or 78%, the ambient noise can be adjusted within the reference noise value. When the engine load enters a high load range, the set accelerator position is returned to, for example, 100%.

  The change control from the set accelerator position to the reference accelerator position is applicable when the engine speed at no load is a high set accelerator position (for example, 80% or more) that is higher than the rated engine speed. In the case of the low set accelerator position, it is not applicable, and the low load range and the high load range are operated only with the set accelerator position set by the accelerator position setter 21.

  In this engine characteristic adjustment method, different engine output characteristic curves are used for different accelerator positions in the high load range and low load range, and in the high load range, the engine output characteristic curve of the high accelerator position is used, which affects the rated output. The sufficient engine power required can be obtained without this. Also, in the low load range, the engine output characteristic curve that is automatically adjusted to the engine speed reduction side according to the ambient noise measurement value is used, so the engine performance is reduced for each aircraft 11 while minimizing the impact on the aircraft performance. Ambient noise can be reduced by lowering the rotational speed, and individual differences in ambient noise due to the airframe 11 can be easily reduced. The ambient noise is large at low loads when the engine speed is high, and it is effective for reducing noise to keep the rotational speed at low loads low.

  The control system adjusted by this engine characteristic adjustment method does not need to be installed in all airframes 11, but is applied only to the airframe 11 with a large ambient noise value as an individual, and the reference accelerator position in the low load range is adjusted for noise. Change and adjust (lower) the accelerator position to meet the reference noise level. As a result, it is not necessary to provide a large margin in the airframe design so as to cope with variations in ambient noise between airframes, and the cost required for noise reduction measures can be suppressed.

  In this way, by mounting the control system having the engine output characteristics adjusted for the ambient noise value on each airframe 11, it becomes possible to reduce the noise with respect to the airframe 11 having a high ambient noise value as a solid, for example, Even the airframe 11 having the ambient noise characteristics shown in FIG. 5A can change the distribution of the ambient noise values as shown in FIG. 5B by this engine control system. The margin for the noise regulation value can be reduced, and individual differences in ambient noise due to the airframe 11 can be easily reduced.

  In the case of FIG. 8, the average noise margin is 0.5 dB relative to the noise regulation value, but in the case of FIG. 5, the average noise margin may be 0.1 dB relative to the noise regulation value. it can. That is, there is an effect of reducing the 0.4 dB margin, and the airframe design becomes easy.

  Next, another embodiment will be described with reference to FIG.

  In the engine characteristic adjustment method shown in FIG. 6, in the system configuration shown in FIG. 2, in the case of the airframe 11 in which the ambient noise measurement value exceeds the reference noise value, the controller 16 has the engine load in the low load range. 4 is common to the embodiment shown in FIG. 4 in that the engine output characteristic curve is changed and adjusted to the engine speed reduction side according to the ambient noise measurement value, but the engine characteristic shown in FIG. The adjustment method is different in that the slope of the droop curve in the engine output characteristic curve is changed and adjusted according to the ambient noise value.

The slope of the droop curve = (no-load rotation speed−rated rotation speed) / no-load rotation speed is generally set at, for example, 10%, which is set according to the ambient noise measurement value. % Or 8%. A reduction to about 5% is possible.

  Even if the slope of the droop curve is changed and adjusted, the same effect as the change and adjustment of the engine accelerator value in the low load range can be obtained. In other words, in the high load range, the required sufficient engine power can be obtained without affecting the rated output, and the droop curve slope can be changed and adjusted according to the ambient noise level. In the load range, it is possible to effectively reduce the engine speed and reduce the ambient noise while suppressing the effect on the aircraft performance, so there is no need to take a large margin in the aircraft design to cope with the variation of each aircraft. The margin for the noise regulation value can be reduced, and individual differences in ambient noise due to the aircraft can be easily reduced.

  As described above, the noise value is adjusted by changing and controlling the engine accelerator value and the droop curve gradient of the engine output characteristic curve having a large influence on the noise. Since this method is effective for both the sound of the engine alone and the cooling fan sound, the effect is particularly great in the airframe 11 having an engine direct connection fan or the like whose fan speed depends on the engine speed.

  The present invention is applicable to a machine body such as a construction machine in which the engine load varies.

It is a flowchart which shows one Embodiment of the engine characteristic adjustment method which concerns on this invention. It is a block diagram of the control system which implements the adjustment method same as the above. (A) is XZ coordinate explanatory drawing at the time of ambient noise measurement used as the premise of the adjustment method same as the above, (b) is XY coordinate explanatory drawing. It is a characteristic view which shows the engine output characteristic of the adjustment method same as the above. It is a characteristic view which shows the example of improvement of the ambient noise characteristic by an adjustment method same as the above, (a) is a characteristic figure before improvement, (b) is a characteristic figure after improvement. It is an engine output characteristic figure which shows other embodiment of the engine characteristic adjustment method which concerns on this invention. It is a characteristic view which shows the engine output characteristic used by the conventional engine control. It is a characteristic view which shows the ambient noise characteristic in the conventional engine control.

Explanation of symbols

11 Airframe
12 engine

Claims (3)

Measure the ambient noise level of the aircraft equipped with the engine,
In the case of an aircraft whose ambient noise value exceeds the noise regulation value, the engine output characteristic curve is changed and adjusted to the engine speed reduction side according to the ambient noise value on condition that the engine load is in the low load range. The engine characteristic adjustment method. To change and adjust the engine output characteristic curve,
The engine characteristic adjustment method according to claim 1, wherein the engine accelerator value in a low load range is changed and adjusted in accordance with an ambient noise value. To change and adjust the engine output characteristic curve,
Change and adjust the slope of the droop curve according to the ambient noise level.
2. The engine characteristic adjusting method according to claim 1, wherein

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