Engine rotational speed controller of high-pressure washer

The present invention relates to an engine speed control device for a high pressure washer.

Conventionally, in a high pressure washer, a technique is known in which a pump is driven by an on-board engine and water pressurized by the pump is discharged. In such a high pressure washer, the engine speed is generally adjusted by a mechanical governor. Therefore, when the operator adjusts the engine speed, the lever (rotation speed adjustment lever) attached to the mechanical governor via a wire is manually operated.

Therefore, in the work where the water discharge work is often temporarily stopped, it is troublesome for the operator to adjust the engine speed each time the water discharge work is stopped or restarted. As a result, even though the water discharge work is stopped, the engine speed is often maintained at the speed during the water discharge work (higher than when the water discharge work is stopped), and the fuel consumption is increased accordingly. There was a problem that the noise became louder as well as worsening.

Therefore, for example, in the technique described in Patent Document 1, when the hand cock attached to the nozzle is closed by the operator (when the operator stops the water discharge operation), the no-load valve (unloading) is performed. The valve) is activated to put the high-pressure pump into no-load operation (no-load state of the pump), and the governor lever of the engine is rotated in conjunction with the movement of the valve body of the no-load valve. This rotation pushes the governor rod connected to the governor lever, and the throttle lever connected to the governor rod is rotated in the closing direction to close the throttle valve, so that the engine speed is automatically reduced. There is.

<patcit num="1"><text>Jikkenhei 6-77869 (paragraphs 0011, 0012, etc.)</text></patcit>

<p> However, in the configuration in which the governor lever is operated according to the displacement of the no-load valve as described in Patent Document 1, a spindle linked to the movement of the valve body of the no-load valve is provided, and a wire is provided between the spindle and the governor lever. It was necessary to route around, and the configuration was complicated.</p><p> Therefore, an object of the present invention is to solve the above-mentioned problems, and to improve (stabilize) workability and improve fuel efficiency by controlling the engine speed according to the execution and stop of the water discharge work with a simpler configuration. An object of the present invention is to provide an engine speed control device for a high pressure washer that is designed to improve and reduce noise.</p>

<p> In order to solve the above problem, in claim 1, the engine speed control device of a high-pressure washer that drives a pump with an mounted engine to pressurize and discharge water from a water discharge unit for cleaning is described above. The water discharge work is executed by the actuator for adjusting the opening degree of the throttle valve provided in the intake passage of the engine, the work execution determination means for determining whether or not the water discharge work is being executed, and the work execution determination means. When it is determined that the engine rotation speed is increased to the working rotation speed, when it is determined that the water discharge work is not executed, the engine rotation speed is decreased to the working rotation speed. It is configured to include an engine speed control means for controlling the drive of the actuator.</p><p> Further, in claim 2, the engine rotation speed detecting means for detecting the engine rotation speed, the throttle opening degree detecting means for detecting the opening degree of the throttle valve, and the detected engine rotation speed are further provided. And an engine output estimating means for estimating whether or not the output of the engine is equal to or higher than the threshold value based on the throttle opening degree, and the work execution determining means estimates that the output of the engine is equal to or higher than the threshold value. When this is done, it is configured to determine that the water discharge operation is being carried out.</p><p> Further, according to claim 3, when the output of the engine is estimated to be equal to or higher than the threshold value continuously for a predetermined time or longer, the work execution determining means determines that the water discharge work is being executed. It was configured as follows.</p><p> Further, in claim 4, a water discharge execution means attached to the water discharge unit and operated by an operator and a water discharge execution signal when the operator operates the water discharge execution means are output. In addition to being provided with a water discharge execution signal output means, the work execution determination means is configured to determine that the water discharge operation is being executed when the water discharge execution signal is input from the water discharge execution signal output means.</p><p> Further, in claim 5, the engine speed change instruction input means attached to the water discharge unit and operated by the operator is provided, and the engine speed control means is the engine speed change instruction. When an instruction from the input means is input, the working rotation speed is changed.</p>

<p> The engine rotation speed control device of the high-pressure washing machine according to claim 1 is provided with an actuator for adjusting the opening degree of the throttle valve provided in the intake passage of the engine, and determines whether or not the water discharge work is being executed. , When it is judged that the water discharge work is being executed, the engine speed is increased to the working speed, while when it is judged that the water discharge work is not being performed, the engine speed is lowered to the working speed. Since it is configured to control the drive of the actuator, it is possible to eliminate the need for the operator to adjust the engine speed, that is, the engine speed is automatically controlled according to the execution and stop of the water discharge work. Therefore, workability can be improved (stable). Furthermore, by lowering the engine speed when the work is stopped, it is possible to improve fuel efficiency and reduce noise.</p><p> Further, in claim 2, the engine speed and the opening degree of the throttle valve are detected, and whether or not the engine output is equal to or higher than the threshold value is estimated based on the detected engine speed and the throttle opening. However, since it is configured to judge that the water discharge work is being executed when the engine output is equal to or higher than the threshold value, it is possible to more accurately judge whether or not the water discharge work is being carried out. The effect described in 1 can be further obtained.</p><p> Further, in claim 3, when the output of the engine is estimated to be equal to or higher than the threshold value continuously for a predetermined time or longer, it is determined that the water discharge operation is being executed. In addition to the effect, the load acting on the engine can be accurately determined (without erroneously determining temporary fluctuations in engine output (accidental fluctuations due to fuel pools, etc.) as load fluctuations). Therefore, it is possible to more accurately switch the engine speed according to the execution and stop of the water discharge work. Furthermore, it is possible to prevent the engine speed from being frequently switched (hunting occurs).</p><p> Further, in claim 4, the water discharge execution means attached to the water discharge unit and operated by the operator, and the water discharge execution signal output means for outputting the water discharge execution signal when the water discharge execution means is operated by the operator. In addition to the above, when the water discharge execution signal is input from the water discharge execution signal output means, it is determined that the water discharge work is being executed. Therefore, the effect described in claim 1 can be obtained with a simple configuration. Can be done.</p><p> Further, in claim 5, when the engine speed change instruction input means attached to the water discharge unit and operated by the operator is provided and the instruction from the engine speed change instruction input means is input, the above-mentioned. Since it is configured to change the rotation speed during work, in addition to the above effects, the operator can change the rotation speed during work (change to the desired amount of water (water pressure)) while performing the water discharge work. The sex can be further improved. Furthermore, since the throttle opening is adjusted by the actuator as described above, the engine speed can be accurately matched with the working speed input via the engine speed change instruction input means. Therefore, it is possible to finely adjust the rotation speed (water amount (water pressure)) during work as compared with the conventional example using the mechanical governor, and the workability can be further improved.</p>

Hereinafter, the best mode for implementing the engine speed control device of the high pressure washer according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view of the main body of the high pressure washer on which the engine speed control device for the high pressure washer according to this embodiment is mounted. Further, FIG. 2 is a left side view of the main body of the high pressure washer shown in FIG.

In FIGS. 1 and 2, reference numeral 10 indicates a high pressure washer. The high-pressure washer 10 includes a frame 12, a handle 14 attached to the frame 12, and wheels 16R, 16L attached to the left and right sides of the frame 12 (left and right when the direction of the arrow is the direction of travel in FIGS. 1 and 2). And.

The engine 18 (internal combustion engine, which will be described later) is mounted near the tip of the frame 12 of the high pressure washer 10, and the pump 20 is mounted near the rear end. The engine 18 includes a recoil starter 22 and is manually started by an operator.

As shown in FIG. 1, the crankshaft 18S of the engine 18 is connected to the pump-side pulley 28 attached to the drive shaft 20S of the pump 20 via a belt 26 wound around the engine-side pulley 24. Therefore, the pump 20 is driven by transmitting the rotational output of the engine 18 to the drive shaft 20S by the belt 26.

A water supply pipe 30 is connected to the pump 20. One end of the water supply pipe 30 is connected to the water inlet 32 of the pump 20, and the other end is connected to a water source (not shown) such as a water supply. Therefore, the water supply pipe 30 serves as a flow path for water supplied to the pump 20.

One end of a water discharge pipe 34, which is a flow path for water pressurized by the pump, is connected to the discharge port of the pump 20 (not visible in FIGS. 1 and 2). A high-pressure hose 36 is connected to the other end of the water discharge pipe 34, and a cleaning gun (water discharge portion) (not shown in FIGS. 1 and 2) is attached to the tip of the high-pressure hose 36.

One end of the reflux pipe 42 is connected to the middle of the water discharge pipe 34 via an unload valve 40 having a pressure regulating function, and the other end is connected to the middle of the water supply pipe 30. That is, the reflux pipe 42 is branched from the water discharge pipe 34 and connected to the water supply pipe 30.

FIG. 3 is a left side view of the washing gun (water discharge part) of the high pressure washer.

In FIG. 3, reference numeral 44 indicates a cleaning gun. The cleaning gun 44 comprises a grip 46, a foregrip 48 and a discharge 50 from which water is discharged. The grip portion 46 includes a grip 52 that is gripped by an operator, and also includes a trigger 54 that is movable with respect to the grip 52. Further, a high-pressure hose connection port 56 is provided at the end (bottom surface) of the grip 52, and is connected to the tip of the high-pressure hose 36 described above. Further, the rotation speed of the engine 18 (the rotation speed during work set higher than the idling rotation speed) is changed (adjusted) at an appropriate position of the grip portion 46, specifically, in the vicinity of the upper part in the gravity direction of the grip 52. Volume 58 (engine speed change instruction input means) is provided. A volume sensor 60 is arranged near the volume 58, and outputs a signal according to the engine speed (working speed) input by the operator via the volume 58.

Further, the discharge portion 50 includes a barrel 62 having a flow path for pumping pressurized water inside, one end of which is connected to the grip portion 46 and the other end of which water is ejected (released). Nozzle 64 is attached. Further, the foregrip 48 described above is attached downward at an appropriate position of the barrel 62.

Here, the operation of the cleaning gun 44 will be briefly described. Inside the cleaning gun 44, a flow path for communicating the high-pressure hose connection port 56 and the nozzle 64 is provided, and the trigger 54 is provided in the flow path. A needle valve (not shown) that opens and closes the flow path mechanically interlocked with the operation is provided. The needle valve opens when the trigger 54 is operated in the direction of the arrow in FIG. 3 by the operator to communicate the flow path with the outside (atmosphere), while it closes when the trigger 54 is not operated. Then, the flow path is sealed (sealed).

Next, the flow of water during the water discharge operation and when the water discharge operation is stopped will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic diagram showing the flow of water during the water discharge work, and FIG. 5 is the one when the work is stopped.

When the operator operates the trigger 54 of the wash gun to perform the water discharge operation, the water is supplied to the water supply pipe 30, the pump 20, the first water discharge pipe 34a, the unload valve 40, and the second, as shown in FIG. It is pumped to the cleaning gun via the water discharge pipe 34b and the high-pressure hose 36 of the above, and water is discharged (injected) from the nozzle 64 of the cleaning gun. That is, the pump 18 is in a state in which a load acts (pump load state). The water pipe 34 from the pump 20 to the unload valve 40 was designated as the first water pipe 34a, and the water pipe 34 from the unload valve 40 to the connection position with the high pressure hose 36 was designated as the second water pipe 34b.

On the other hand, when the water discharge operation is stopped (that is, when the trigger 54 of the cleaning gun is not operated by the operator), the flow path is sealed by the needle valve in the cleaning gun as described above, and thus the water pressure in the flow path (that is, when the water pressure in the flow path is not operated). The pressure of water between the flow path and the unload valve 40) rises sharply. Due to this increase in water pressure, the unload valve 40 operates (specifically, the check valve (not shown) inside the unload valve closes, and the piston inside the unload valve is connected to the relief valve. (Not shown) is pushed up) to communicate the first water discharge pipe 34a and the return pipe 42, and close the flow path that communicates the first water discharge pipe 34a and the second water discharge pipe 34b. As a result, water is circulated through the water supply pipe 30, the pump 20, the first water discharge pipe 34a, the unload valve 40, and the return pipe 42, as shown in FIG. That is, there is almost no load acting on the pump 20 (pump no load state).

FIG. 6 is an explanatory cross-sectional view of the engine 18.

The engine 18 includes one cylinder (cylinder) 70, and the piston 72 is housed in the cylinder 70 so as to be reciprocating. A combustion chamber 74 is formed between the head of the piston 72 and the wall surface of the cylinder, and an intake valve 76 and an exhaust valve 78 are arranged on the wall surface of the cylinder, and between the combustion chamber 74 and the intake passage 80 or the exhaust passage 82. Open and close. Specifically, the engine 18 is an air-cooled 4-cycle single-cylinder OHV type internal combustion engine, and has a displacement of 163 cc.

The piston 72 is connected to the crankshaft 18S described above, and the crankshaft 18S is connected to the camshaft 86 via a gear. A flywheel 88 is attached to one end of the crankshaft 18S, and the recoil starter 22 described above is attached to the tip side of the flywheel 88. Although not shown, the engine-side pulley 24 is attached to the other end of the crankshaft 18S.

A power generation coil (alternator) 90 is arranged inside the flywheel 88 to generate alternating current. The alternating current generated by the power generation coil 90 is converted into a direct current through a processing circuit (not shown), and then supplied to an ECU (described later), an ignition circuit (not shown), or the like as an operating power source.

A throttle body 92 is arranged upstream of the intake passage 80. A throttle valve 94 is housed in the throttle body 92, and the throttle valve 94 is connected to an electric motor 96 (actuator, specifically, a stepping motor) via a throttle shaft and a reduction gear mechanism (both not shown). Further, in the throttle body 92, a carburetor asy (not shown) is provided on the upstream side of the throttle valve 94. The carburetor asy is connected to a fuel tank (not shown) and injects gasoline fuel into the intake air according to the opening degree of the throttle valve 94 to generate an air-fuel mixture. The generated air-fuel mixture is sucked into the combustion chamber 74 of the cylinder 70 through the throttle valve 94, the intake passage 80 and the intake valve 76.

A throttle opening sensor 98 is arranged near the electric motor 96, and outputs a signal corresponding to the opening θTH (hereinafter referred to as throttle opening) of the throttle valve 94. Further, a crank angle sensor 100 composed of an electromagnetic pickup is arranged near the flywheel 88, and a pulse signal is output for each predetermined crank angle.

The outputs of the throttle opening sensor 98, the crank angle sensor 100, and the volume sensor 60 are input to the ECU (electronic control unit) 102. The ECU 102 consists of a microcomputer equipped with a CPU, ROM, RAM and a counter, and is arranged at an appropriate position of the high pressure washer 10.

Here, the engine speed control in the ECU 102 will be described with reference to FIG. FIG. 7 is a block diagram functionally showing the configuration of engine speed control of the high pressure washer.

As shown in FIG. 7, the ECU 102 counts the output pulse of the crank angle sensor 100 to detect (calculate) the engine speed NE. Further, the ECU 102 has an energization command value of the electric motor 96 so that the engine speed NE matches the target speed NED based on the detected engine speed NE and the throttle opening θTH output from the throttle opening sensor 98. Is calculated, and the calculated energization command value is output to the electric motor 96 to control its drive.

Further, the engine speed (working speed NEDa) desired by the operator is input to the ECU 102 via the volume 58 (volume sensor 60) by the operator.

In this way, the high-pressure washer 10 according to this embodiment opens and closes the throttle valve 94 by an electronically controlled throttle device (electronic governor) including a throttle body 92, an ECU 102, various sensors, and the like, and the intake air amount of the engine 18. The engine speed NE is controlled by adjusting the amount, and the engine speed NE (working speed NEDa) can be input by the operator.

Next, the operation of the engine speed control device of the high pressure washer according to this embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing the operation. The illustrated program is executed in the ECU 102 every predetermined period (for example, 20 [msec]).

Before going into the description of FIG. 8, it is outlined to determine whether or not the water discharge operation in this embodiment is being performed, in other words, whether the pump is in a pump-loaded state or a pump-free state. FIG. 9 is a graph showing the characteristics of the engine output OP with respect to the engine speed NE during the water discharge work (pump load state) and when the water discharge work is stopped (pump no load state). The engine output OP is a value (parameter) representing the engine load.

As shown in FIG. 9, the characteristics of the engine output OP with respect to the engine speed NE are significantly different (polarized) between the water discharge work (pump load state) and the water discharge work stop (pump no load state). Based on this characteristic, it is judged whether or not the engine output OP is equal to or higher than the threshold value OP1 (for example, 1.0 [PS]), and whether or not it is during water discharge work (pump is under load or no pump). Changed to judge which of the load states).

FIG. 10 shows the throttle opening θTH with respect to the engine speed NE from the engine speed NEDi (idling speed) to NEDmax (maximum value that the work speed NEDa can take) when the engine output OP is the threshold OP1. It is a graph which shows the characteristic of.

As shown in FIG. 10, the throttle opening θTH with respect to the engine speed NE when the engine output OP is a constant value (predetermined value, for example, the threshold value OP1) can be mapped in advance through experiments. That is, the throttle opening when the engine output OP is the threshold value OP1 can be obtained from the current engine speed NE. For example, the throttle opening when the engine speed NE is the work stop speed NEDi (idling speed) is θTHref (hereinafter referred to as throttle opening threshold θTHref).

Therefore, in this embodiment, the current throttle opening θTH and the throttle opening threshold θTHref are compared, and if the throttle opening θTH is equal to or greater than the throttle opening threshold θTHref, the current engine output OP is thresholded. It is estimated that the value is OP1 or more. On the other hand, if it is less than the throttle opening threshold value θTHref, it is estimated that the current engine output OP is less than the threshold value OP1. Similarly, when the engine speed NE is the working speed NEDa, the throttle opening threshold value θTHref can be obtained from the characteristics shown in the figure.

Returning to the explanation of FIG. 8, first, in S10, the engine speed NE is detected and the detected engine speed NE is stored in the RAM of the ECU 102. Next, the process proceeds to S12, and it is determined whether or not the detected value of the engine speed NE has been saved for a predetermined cycle (for example, 10 cycles). If it is denied by S12, the subsequent processing is skipped, while if it is affirmed by S12, the process proceeds to S14 and the average engine speed NEavg is calculated. The average engine speed NEavg is the average value of the engine speed NE for a predetermined stored cycle (10 cycles).

Next, proceed to S16, detect the current value of the throttle opening θTH, and further proceed to S18 to set the target rotation speed NED of the engine 18 to the rotation speed NEDi (idling rotation speed, for example, 2000 [rpm]) when the work is stopped. Determine if it is set. The target rotation speed NED is set to the rotation speed NEDi when the work is stopped when the ECU 102 is started.

If it is affirmed in S18, then proceed to S20 and estimate whether the engine output OP is equal to or higher than the threshold OP1. Specifically, as described above, it is estimated whether or not the engine output OP is the threshold OP1 or more based on the average engine speed NEavg (generally, the engine speed NE) and the throttle opening θTH. Therefore, it is determined whether or not the water discharge work is being carried out.

When it is denied by S20 (when it is judged that the engine output OP is less than the threshold OP1 (water discharge work is not executed)), the subsequent processing is skipped and the target rotation speed NED is the rotation speed NEDi when the work is stopped. When it is affirmed at S20 (when it is judged that the engine output OP is equal to or higher than the threshold OP1 (water discharge work is being executed)), the process proceeds to S22 and over the first predetermined time t1 ( (Continued) Determine if the engine output OP is greater than or equal to the threshold OP1. To make this judgment, start the counter with another program (not shown) when it is affirmed in S20, and check whether the counter value has reached the first predetermined time t1 (for example, 1 [sec]). Is done by.

If it is denied by S22, the subsequent processing is skipped and the target rotation speed NED is maintained at the rotation speed NEDi when the work is stopped, while if it is affirmed by S22, it proceeds to S24 and is operated by the operator via volume 58. Read the set working speed NEDa (for example, 3600 [rpm]).

Next, proceed to S26 and change (increase) the target rotation speed NED to the working rotation speed NEDa read in S24. As a result, the ECU 102 controls the electric motor 96 so that the engine speed NE matches the changed target speed NED, and thus the engine speed NE increases.

If the target rotation speed NED is changed to the working rotation speed NEDa in S26, it will be denied in S18 and proceed to S28 at the next program loop, and whether the engine output OP is less than the threshold OP1 like S20, that is, , Judge whether the water discharge work has been stopped (not executed).

When it is denied by S28 (when it is judged that the engine output OP is equal to or higher than the predetermined value OP1 (water discharge work is being executed)), the subsequent processing is skipped and the target rotation speed NED is maintained at the work rotation speed NEDa. On the other hand, when it is affirmed in S28 (when it is judged that the engine output OP is less than the predetermined value OP1 (water discharge work is not executed)), the process proceeds to S30 and the second predetermined time t2 is continued (continuously). ) Judge whether the engine output OP is less than the predetermined value OP1. As with S22, when this judgment is affirmed in S28, the counter is started by another program (not shown), and it is confirmed whether the counter value reaches the second predetermined time t2 (for example, 1 [sec]). It is done by doing.

If it is denied by S30, the subsequent processing is skipped and the target rotation speed NED is maintained at the working rotation speed NEDa, while if it is affirmed by S30, it proceeds to S32 and the target rotation speed NED is rotated when the work is stopped. Change (lower) to the number NEDi. As a result, the ECU 102 controls the electric motor 96 so that the engine speed NE matches the changed target speed NED, and thus the engine speed NE decreases.

As described above, in this embodiment, the engine speed NE (engine speed NEavg) and the throttle opening θTH are detected (calculated), and the engine output OP is equal to or higher than the threshold OP1 based on these values. Estimate whether or not, and change the engine speed NE (target rotation speed NED) according to the result, specifically, the rotation speed NEDi (idling rotation speed) at work stop and set higher than that. Since it is configured to switch between the work speed and NEDa, it is possible to accurately determine whether or not the water discharge work is being executed, and it is not necessary for the operator to adjust the engine speed. it can. That is, the engine speed can be automatically controlled according to the execution and stop of the water discharge work, and the workability can be improved (stable). Furthermore, by lowering the engine speed when the work is stopped, it is possible to improve fuel efficiency and reduce noise.

When the target rotation speed NED is the rotation speed NEDi when the work is stopped and the engine output OP is estimated to be equal to or higher than the threshold OP1 over the first predetermined time t1, the engine rotation speed NE (target rotation speed NED) is worked. The stop rotation speed NEDi is changed (increased) from the work rotation speed NEDa set to a higher value, while the target rotation speed NED is the work rotation speed NEDa over the second predetermined time t2. When the engine output OP is estimated to be less than the threshold OP1, the engine speed NE (target speed NED) is changed (decreased) from the work speed NEDa to the work stop speed NEDi. , The load acting on the engine 18 can be accurately determined, and therefore the engine speed NE can be switched more accurately according to the execution and stop of the water discharge work. Furthermore, it is possible to prevent the engine speed NE from being frequently switched (hunting occurs).

In addition, since the operator can set the working speed NEDa via the volume 58 attached to the cleaning gun 44 to obtain the desired engine speed, the operator can perform the water discharge work. The number of rotations during work can be changed (changed to a desired amount of water (water pressure)), and thus workability can be further improved. Furthermore, since the throttle opening θTH is adjusted by the electric motor 96 (actuator), the engine speed NE can be accurately matched to the working speed NEDa input via the volume 58. Therefore, it is possible to finely adjust the rotation speed (water amount (water pressure)) during work as compared with the one using a mechanical governor, and the workability can be further improved.

Next, the engine speed control device of the high pressure washer according to the second embodiment of the present invention will be described with reference to FIGS. 11 and 11 and thereafter.

FIG. 11 is a left side view of the water discharge portion (washing gun) 442 according to the second embodiment. Further, FIG. 12 is a block diagram functionally showing the configuration of engine speed control of the high pressure washer according to the second embodiment. In the following description, the same reference numerals will be given to the configurations common to those of the first embodiment, and the description thereof will be omitted.

In the cleaning gun 442 according to the second embodiment, as shown in FIG. 11, the trigger sensor 104 is arranged in the vicinity of the trigger 54. When the trigger 54 is operated by the operator in the direction of the arrow in FIG. 11, the trigger sensor 104 outputs an on signal to the ECU 102 as shown in FIG. 12, and outputs an off signal when the trigger 54 is not operated. ..

Next, the operation of the engine speed control device of the high pressure washer according to the second embodiment will be described with reference to FIGS. 13 and 14. FIG. 13 is a flowchart showing the operation, which is executed in the ECU 102 every predetermined cycle (for example, 20 [msec]). Further, FIG. 14 is a time chart showing a change in the target rotation speed NED with respect to the output of the trigger sensor 104.

Explaining the following, in S100, it is determined whether or not the trigger sensor 104 outputs an on signal, that is, whether or not the water discharge operation is being executed. If the result is affirmed by S100, the process proceeds to S102, and the working rotation speed NEDa (for example, 3600 [rpm]) set by the operator via the volume 58 is read.

Then, the process proceeds to S104, and as shown in FIG. 14, the target rotation speed NED is immediately changed (increased) to the working rotation speed NEDa read by S102. As a result, the ECU 102 controls the electric motor 96 so that the engine speed NE matches the changed target speed NED, and thus the engine speed NE increases. While the ON signal is output, the engine speed NE is maintained at the working speed NEDa.

On the other hand, when it is denied by S100, that is, when the trigger sensor 104 is outputting an off signal, the process proceeds to S106, and as shown in FIG. 14, the target rotation speed NED is immediately set to the rotation speed NEDi when the work is stopped (for example, 2000). Change to [rpm]) (lower). As a result, the ECU 102 controls the electric motor 96 so that the engine speed NE matches the changed target speed NED, and thus the engine speed NE decreases. While the off signal is output, the rotation speed NE is maintained at the rotation speed NEDi when the work is stopped.

Since the remaining configuration is the same as that of the first embodiment, the description thereof will be omitted.

In this way, in the second embodiment, when the on signal is output from the trigger sensor 104 by operating the cleaning gun 442, the rotation speed NE (target rotation speed NED) of the engine 18 is stopped. While the rotation speed NEDi is changed to the work speed NEDa, when the off signal is output, the engine speed NE (target rotation speed NED) is changed from the work speed NEDa to the work stop speed NEDi. Since it is configured in this way, the engine speed can be set according to the execution and stop of the water discharge work with a simple configuration, and thus the workability can be improved (stable). Furthermore, since the engine speed is reduced when the work is stopped, it is possible to improve fuel efficiency and reduce noise.

As described above, in the first and second embodiments of the present invention, the pump (20) is driven by the mounted engine (18) to pressurize and discharge water from the water discharge unit (cleaning guns 44, 442) for cleaning. In the engine speed control device of the high-pressure washer (10), an actuator (electric motor 96) that adjusts the opening degree (θTH) of the throttle valve (94) provided in the intake passage (80) of the engine (18). The water discharge work is executed by the work execution determination means (ECU102; S20, S28 in the flowchart of FIG. 8 and S100 in the flowchart of FIG. 13) for determining whether or not the water discharge operation is being executed, and the work execution determination means. When it is determined that the engine speed (NE) is increased to the working speed (NEDa) (S26 in the flowchart of FIG. 8 and S104 in the flowchart of FIG. 13), on the other hand, it is determined that the water discharge operation is not executed. When the engine rotation speed (NE) is reduced to the rotation speed (NEDi) when the work is stopped (S32 in the flowchart of FIG. 8 and S106 in the flowchart of FIG. 13), the engine rotation that controls the drive of the actuator (96). It was configured to include a number control means (102).

In the first embodiment of the present invention, the engine rotation speed detecting means (crank angle sensor 100, S10, S14 in the flowchart of FIG. 8) for detecting the rotation speed (NE) of the engine (18), and the throttle valve. To the throttle opening detection means (throttle opening sensor 98, S16 in the flowchart of FIG. 8) for detecting the opening (θTH) of (94), and the detected engine rotation speed (NE) and throttle opening (θTH). It is equipped with an engine output estimation means (ECU102; S20, S28 in the flowchart of FIG. 8) for estimating whether or not the output (OP) of the engine (18) is equal to or higher than the threshold value (OP1). When the output (OP) of the engine (18) is estimated to be equal to or higher than the threshold value (OP1), the means determines that the water discharge operation is being executed (S20, S28 in the flowchart of FIG. 8). Configured.

Further, when the output (OP) of the engine is estimated to be the threshold value (OP1) or more continuously for a predetermined time (t1) or more, the work execution determination means (ECU102) executes the water discharge work. It was configured to determine that it was present (S20, S22 in the flowchart of Fig. 8).

Further, in the second embodiment of the present invention, a water discharge executing means (trigger 54) attached to the water discharge unit (cleaning gun 442) and operated by the operator, and the water discharge execution means by the operator. A water discharge execution signal output means (trigger sensor 104) that outputs a water discharge execution signal when the means is operated is provided, and the work execution determination means (ECU102) receives the water discharge execution signal from the water discharge execution signal output means. When it is input, it is determined that the water discharge work is being executed (S100 in the flowchart of FIG. 13).

Further, the first and second embodiments of the present invention further include an engine speed change instruction input means (volume 58) attached to the water discharge unit (cleaning guns 44, 442) and operated by an operator. At the same time, the engine speed control means (ECU102) changes the work speed (NEDa) when an instruction from the engine speed change instruction input means is input (S24, FIG. 13 in the flowchart of FIG. 8). It was configured as shown in S102) of the flowchart.

In the above, the numerical values of the work rotation speed NEDa, the work stop rotation speed NEDi, the threshold value OP1, and the first and second predetermined times t1 and t2 are specifically shown, but the values are not limited to these values. Needless to say.

Further, although the stepping motor is used as the actuator for opening and closing the throttle valve 94, another actuator such as a DC motor or a rotary solenoid may be used.

Further, although water has been exemplified as the fluid used for cleaning, it is needless to say that the fluid is not limited to that, and may be a cleaning liquid or even a paint.

<figref num="1">It is a top view of the main body of the high pressure washer on which the engine speed control device of the high pressure washer which concerns on 1st Embodiment of this invention is mounted.</figref><figref num="2">It is a left side view of the main body of the high pressure washer shown in FIG.</figref><figref num="3">It is a left side view of the water discharge part (washing gun) of the high pressure washer which concerns on 1st Example.</figref><figref num="4">It is a schematic diagram which shows the flow of water at the time of the water discharge operation of the high pressure washer shown in FIG.</figref><figref num="5">It is a schematic diagram which shows the flow of water when the water discharge of a high pressure washer shown in FIG. 1 is stopped.</figref><figref num="6">It is explanatory sectional view of the engine shown in FIG.</figref><figref num="7">It is a block diagram which functionally shows the operation of the engine speed control device of the high pressure washer which concerns on 1st Example.</figref><figref num="8">It is a flowchart which shows the operation of the engine speed control device of the high pressure washer which concerns on 1st Example.</figref><figref num="9">It is a graph which shows the characteristic of the engine output with respect to the engine speed of the high pressure washer shown in FIG.</figref><figref num="10">It is a graph which shows the characteristic of the throttle opening with respect to the engine speed at the threshold OP1 that the engine output of the high pressure washer shown in FIG.</figref><figref num="11">It is a left side view of the water discharge part (washing gun) which concerns on 2nd Example.</figref><figref num="12">It is a block diagram which functionally shows the operation of the engine speed control device of the high pressure washer which concerns on 2nd Example.</figref><figref num="13">It is a flowchart which shows the operation of the engine speed control device of the high pressure washer which concerns on 2nd Example.</figref><figref num="14">It is a time chart which shows the change of the target rotation speed with respect to the output of the trigger sensor shown in FIG.</figref>

Code description

10 High-pressure washing machine 18 Engine 20 Pump 44,442 Cleaning gun (water discharge part) 54 Trigger (water discharge executing means) 58 Volume (engine speed change instruction input means) 94 Throttle valve 96 Electric motor (actuator) 98 Throttle opening sensor (throttle open) Degree detection means) 100 Crank angle sensor (engine speed detection means) 102 ECU (work execution judgment means, engine speed control means, engine output estimation means) 104 Trigger sensor (water discharge execution signal output means)