JP4563876B2 - Engine oil level detector - Google Patents

Description

  The present invention relates to an engine oil level detection device.

The engine is configured to lubricate each sliding portion with lubricating oil stored in a crankcase. Various oil level detection devices that detect the level of such lubricating oil are known (see, for example, Patent Document 1-2).
Utility Model Registration No. 2532891 Japanese Patent Publication No. 55-45733

The conventional oil level detection device for an engine according to Patent Document 1 is to stop the engine when the level of the lubricating oil has dropped below a certain level.
The conventional oil level detection device for an engine according to Patent Document 2 is to turn on an indicator lamp and issue an alarm when the level of lubricating oil has fallen above a certain level.

A conventional engine oil level detection device according to Patent Document 1 will be described with reference to FIG. 11 (a) and 11 (b) are block diagrams of a conventional engine oil level detection device.
FIG. 11A shows a cross-sectional structure of the engine 100. A conventional engine 100 is a general-purpose engine in which lubricating oil 102 is stored at the bottom of a crankcase 101. The lubricating oil 102 is scraped up and supplied to each sliding portion in the crankcase 101 as the crankshaft 103 rotates. An oil scooping unit 104 and a float type oil level detector 111 for detecting the level of the lubricating oil 102 are provided.
Regarding the level of the lubricating oil 102, the upper limit level L1 is set at the highest level, the lower limit level L2 is set below the upper limit level L1, and the lower limit level L3 is set below the lower limit level L2.

  FIG. 11B shows the oil level detection device 110 when the lubricating oil 102 is accumulated up to the upper limit level L1. The oil level detection device 110 is configured to notify or stop the engine 100 according to the levels L1 to L3 detected by the float type oil level detector 111. Specifically, the float type oil level detector 111 includes a float 113 in a case 112 and a conductive vertical bar 114 fixed to the float 113.

  Assume that engine 100 is now operating. When the lubricating oil 102 is lowered to the lower limit level L2, the vertical bar 114 is lowered together with the float 113, and the lower end thereof contacts the bottom surface 101a of the crankcase 101. As a result, the battery 115 → the warning lamp 116 → the conductive ring 112a of the case 112 → the vertical bar 114 → the passage through the path of the bottom surface 101a of the crankcase 101. The warning lamp 116 is turned on to notify that it is the lower limit level L2.

  Furthermore, when the lubricating oil 102 is lowered to the lowest limit level L3, the movable contact 117 provided on the lower surface of the float 113 comes into contact with the fixed contacts 118 and 118. As a result, the ignition device 119 stops the engine 100 by stopping the ignition operation.

Now, consider the case where the engine 100 is mounted on various working machines. The work machine is divided into a stationary type and a mobile type (portable type).
The engine 100 mounted on a stationary work machine such as a generator or a high-pressure washing machine does not shake because the work machine itself does not shake. For this reason, the oil level of the lubricating oil 102 hardly changes. Therefore, the engine 100 can be automatically stopped when the level of the lubricating oil has fallen above a certain level.

On the other hand, the engine 100 mounted on a mobile work machine such as a field cultivator can swing greatly when moved together with the mobile work machine. For this reason, compared with the case where it is mounted on a stationary work machine, the oil level of the lubricating oil 102 is greatly shaken. Moreover, since the lubricating oil 102 is scooped up by the oil scooping unit 104, the fluctuation of the oil level is large.
As the float 113 moves up and down according to the oil level fluctuation, the movable contact 117 also moves up and down. If the movable contact 117 moves up and down greatly in a state where the lubricating oil 102 is lowered, it may be detected that the actual level has dropped to the lower limit level L3 even though the actual level has not dropped to the lower limit level L3. As a result, the engine 100 stops.
For this reason, in the case of the engine 100 mounted on the mobile work machine, the engine 100 cannot be automatically stopped when the level of the lubricating oil decreases by a certain level or more.

  Therefore, (1) when the engine 100 is mounted on a stationary work machine, an oil level detection device 110 capable of automatically stopping the engine 100 is prepared, and (2) when the engine 100 is mounted on a mobile work machine. Therefore, an oil level detection device 110 that does not automatically stop the engine 100 is prepared. In this case, it is necessary to prepare two types of oil level detection devices 110 according to the type of load such as a work machine, which increases the number of man-hours for management and the manufacturing cost, so there is room for improvement.

  The present invention is a technique that can cope with both a case where the engine is automatically stopped and a case where the engine is not stopped when the level of the lubricating oil in the crankcase is lowered by a certain level using one kind of oil level detection device. It is an issue to provide.

According to the first aspect of the present invention, an oil scooping portion that scoops up lubricating oil and supplies it to each sliding portion as the crankshaft rotates in the crankcase, and a float type oil level detection that detects the level of the lubricating oil. The float type oil level detector has a movable contact point that contacts the fixed contact when the lubricating oil level drops to a preset lower limit level. Thus, in the engine oil level detection device that issues a detection signal for level drop,
The engine oil level detection device operates a first mode in which the alarm is activated and the engine is stopped in response to the detection signal, and a second mode in which the alarm is activated in accordance with the detection signal and the operation state of the engine is continued. in, comprising a switching means for switching in accordance with the kind of the working machine, and a first determining means and the second determining means determines the level reduction of the real said lubricating oil, said first determining means, the engine When the two conditions of the condition that the detection signal is stopped and the condition that the time during which the detection signal lasts has reached a preset first reference time are satisfied, The second determining means is configured to determine that the level has decreased to the lower limit level, and the second determining means for a period shorter than a condition that the engine is operating and a preset second reference time. It is determined that the actual level of the lubricating oil has decreased to the lower limit level when the two conditions, the condition that the number of detection signals received in step S1 has reached a preset reference number, are satisfied. It is configured as described above.

  The invention according to claim 2 is characterized in that, in claim 1, the switching means is constituted by a manual operation switch, and the manual operation switch is attached to an operation panel attached to the engine.

  According to a third aspect of the present invention, in the first aspect, the switching means includes a memory that is provided in the engine and stores the mode switching data, and a switching unit that switches between the first mode and the second mode based on the mode switching data. The memory is configured such that mode switching data can be written by an external communication means.

  In the invention according to claim 1, in the oil level detection device for an engine employing a float type oil level detector that generates a detection signal for level reduction when the movable contact provided on the float contacts the fixed contact, the level reduction Switching means between a first mode for operating the alarm and stopping the engine in response to the detection signal, and a second mode for operating the alarm and continuing the engine operating state in response to the level-down detection signal. Can be switched.

That is, in the invention according to claim 1, when one level of the oil level detection device is used and when the level of the lubricating oil in the crankcase is lowered by a certain level, the engine is automatically stopped or not stopped. In addition, it can be switched by switching means.
Therefore, it is possible to easily cope with both the case where the engine is automatically stopped and the case where the engine is not stopped with only one type of oil level detection device. Since only one type of oil level detection device needs to be prepared, the man-hours for managing the oil level detection device can be reduced, and the manufacturing cost can be reduced. In addition, all kinds of loads (for example, working machines in all working forms) can be handled with one kind of oil level detection device.
Further, the invention according to claim 1 is characterized in that the oil level detection device includes two determination means, a first determination means and a second determination means, for determining an actual level drop of the lubricating oil. And
The first judging means judges that the level is actually lowered when the engine is stopped and the level lowering detection signal (contact of the movable contact) continues for a certain period of time. Ideal for level detection inside.
On the other hand, when the number of detection signals for level reduction received at an interval shorter than a preset second reference time during engine operation reaches a certain number, the second judgment means actually reduces the level. Since it is determined that there is, it is most suitable for level detection during engine operation.
In this way, the oil level detection device can detect the engine oil level more accurately and reliably both when the engine is stopped and with a simple configuration having only two judgment means. Can do.

  In the invention according to claim 2, since the switching means is constituted by a manual operation switch, and this manual operation switch is attached to the operation panel of the engine, the user can easily operate the switching means to switch between the first mode and the first mode. Two modes can be switched.

  In the invention according to claim 3, the mode switching data is written in the memory provided in the engine by an external communication means, so that the switching unit switches between the first mode and the second mode based on the mode switching data. Switch automatically. Therefore, the user does not need to switch to the first mode or the second mode.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. Note that “front”, “rear”, “left”, and “right” follow directions viewed from the power take-out side of the crankshaft.
FIG. 1 is a cross-sectional view of an engine according to the present invention as seen from the front, and shows the engine as seen from the power take-out portion side of the crankshaft 14. The engine 10 is an inclined cylinder type OHC air-cooled single cylinder internal combustion engine in which a cylinder 21 is inclined with respect to a substantially horizontal crankshaft 14 when viewed from the front as shown in FIG. Hereinafter, the engine 10 will be described in detail.

The crankcase 11 of the engine 10 is an integrated case in which a crank chamber 12 and a cylinder block 13 are integrally formed. The crank chamber 12 is configured to house the crankshaft 14 and rotatably support it.
The crankshaft 14 is obtained by connecting a connecting rod 16 to a crankpin 15 in the crank chamber 12 and connecting a piston 17 to the connecting rod 16.
The cylinder block 13 has a cylinder 21 formed therein, and a cylinder head 22 is bolted to the tip, and a combustion chamber 23 is formed between the tip of the cylinder 21 and the cylinder head 22. An intake port (not shown) and an exhaust port 25 are formed. The piston 17 can reciprocate in the cylinder 21.

The cylinder head 22 has a valve operating chamber 27 formed by closing the tip portion with a head cover 26. The valve mechanism 30 is arranged in the valve chamber 27.
The valve operating mechanism 30 includes a cam shaft 31, a rocker shaft 32, an intake valve rocker arm 33, an intake valve 34, an exhaust valve rocker arm 35, and an exhaust valve 36, which are attached to the cylinder head 22 as main components. It is.

The cam shaft 31 is rotatably supported by the cylinder head 22 and is driven by a crankshaft 14 via a power transmission mechanism (not shown), and further includes an intake valve driving cam 37 and an exhaust valve. A drive cam 38 is provided.
As the camshaft 31 rotates, the intake valve drive cam 37 and the exhaust valve drive cam 38 are displaced to swing the intake / exhaust valve rocker arms 33, 35. As a result, the intake / exhaust valve 34, 36 opens and closes at a predetermined opening and closing timing.

  Further, the engine 10 detects the level of the lubricating oil Lu in the crankcase 11 and the oil scraping section 40 (oil dipper 40) that scrapes the lubricating oil Lu along with the rotation of the crankshaft 14 and supplies it to each sliding portion. And a float type oil level detector 50 (oil alert 50).

  More specifically, the connecting rod 16 includes an oil scraping portion 40 for scraping the lubricating oil Lu in the lower portion (oil pan) of the crank chamber 12. By rotating the oil scraping portion 40, the lubricating oil Lu accumulated in the lower portion of the crank chamber 12 can be scraped up and scattered in the crank chamber 12 and the cylinder 21. The scattered lubricating oil Lu enters the sliding portions of the members in the crank chamber 12 and the cylinder 21 and lubricates them.

  2 (a) and 2 (b) are main part configuration diagrams and operation diagrams of the float type oil level detector according to the present invention. (A) shows the cross-sectional structure of the principal part of the float type oil level detector 50 in a state where the lubricating oil Lu is sufficiently accumulated up to the upper limit level L11. (B) shows the cross-sectional structure of the principal part of the float type oil level detector 50 in a state where the lubricating oil is lowered to the lower limit level L12.

  As shown in FIGS. 1 and 2, the float-type oil level detector 50 is configured such that when the actual level Lr of the lubricating oil Lu (the oil level Lr) decreases to a preset lower limit level L12, This is a sensor that generates a detection signal for level reduction when the movable contact 55 provided on the float 54 contacts the fixed contacts 56, 56.

  More specifically, as shown in FIG. 2A, the float type oil level detector 50 includes a bottomed cylindrical case body 51 having an open upper end and a lid that covers the upper end opening of the case body 51. 52, a float chamber 53 formed by surrounding the case body 51 and the lid 52, a float 54 accommodated in the float chamber 53 so as to be movable up and down, a movable contact 55 provided on the bottom surface of the float 54, a movable contact It is composed of a pair of fixed contacts 56, 56 provided on the bottom plate 51 a of the case main body 51 so as to oppose 55.

The bottom plate 51 a and the lid 52 of the case body 51 have passage holes 51 b and 52 a through which the lubricating oil Lu passes inside and outside the float chamber 53. The bottom plate 51a of the case body 51 is covered with a cover 57 with a certain gap. The cover 57 has a rear opening 57a and a lower passage hole 57b through which the lubricating oil Lu passes.
The rear opening 57a is open on the side surface of the cover 57 opposite to the rotation direction of the oil scraping portion 40 (see FIG. 1). For this reason, the influence of the fluctuation | variation of the oil level by scooping up the lubricating oil Lu by the oil scooping part 40 can be suppressed as much as possible.

  The float 54 is an electrically insulating, generally donut-shaped float that floats on the oil surface and moves up and down following the oil surface. The movable contact 55 is a conductive flat horizontal disk. The pair of fixed contacts 56, 56 are conductive members that rise upward from the bottom plate 51a. The combined structure of the movable contact 55 and the pair of fixed contacts 56, 56 constitutes an oil level switch 58.

Next, the operation of the float type oil level detector 50 will be described.
As shown in FIG. 2A, in a state where the lubricating oil Lu is sufficiently accumulated up to the upper limit level L11, the float 54 floats on the oil surface. In this state, the movable contact 55 is separated from the pair of fixed contacts 56 and 56. As a result, the oil level switch 58 is in an off state.
Thereafter, as shown in FIG. 2 (b), the float 54 descends to the lowest part of the float chamber 53 in a state where the oil level of the lubricating oil Lu is lowered to the lower limit level L 12. In this state, the movable contact 55 is in contact with the pair of fixed contacts 56 and 56. As a result, the oil level switch 58 is inverted to an ON state, and a level drop detection signal is issued.

FIG. 3 is a rear view of the engine according to the present invention, and shows the engine 10 viewed from the side opposite to FIG. As shown in FIG. 3, the engine 10 includes a main switch 62, a notification device 63, and a changeover switch 64 on an operation panel 61 provided on the back surface.
The main switch 62 is a manual operation switch that switches between starting and stopping of the engine 10 by turning a knob. The alarm device 63 includes a display device such as a display lamp, and a sound alarm device such as a buzzer. The changeover switch 64 is a manually operated switch such as a swing switch or a push button switch that can be manually operated. Further, as shown in FIG. 3, the engine 10 includes a control unit 65 at the operation panel 61 or at an arbitrary position.

Next, an oil level detection device 60 using the float type oil level detector 50 will be described with reference to FIG.
FIG. 4 is a circuit diagram of an engine oil level detection device according to the present invention. The oil level detection device 60 includes a float type oil level detector 50, a main switch 62, a notification device 63, a changeover switch 64, a control unit 65, a trigger pulse generation unit 66, an ignition device 67 of the engine 10, and a rotation sensor 68.

The control unit 65 receives signals from the float type oil level detector 50, the main switch 62, the changeover switch 64, the trigger pulse generation unit 66, and the rotation sensor 68, and issues a control signal to the alarm device 63 and the ignition device 67. is there.
The trigger pulse generator 66 generates a trigger pulse signal based on the detection signal of the float type oil level detector 50. The trigger pulse generator 66 generates, for example, one pulse signal each time an ON signal is received from the oil level switch 58, that is, every time the oil level switch 58 is "inverted from OFF to ON". It consists of a stable multivibrator.
The ignition device 67 emits high-voltage electricity to an ignition plug (not shown) of the engine 10. The rotation sensor 68 detects the rotation speed of the engine 10.

  Next, a control flow when the control unit 65 shown in FIG. 4 is a microcomputer will be described with reference to FIGS. This control flow starts when the main switch 62 is turned on, for example, and ends when the main switch 62 is turned off. In the figure, STxx indicates a step number. Step numbers that are not specifically described proceed in numerical order. Hereinafter, a description will be given with reference to FIGS.

FIG. 5 is a control flowchart (No. 1) of the control unit according to the present invention, and shows the first half of the control flow. In addition, the control part 65 incorporates the 1st timer 71, as shown in FIG.
ST01: Initial setting is performed. Specifically, the count time Tc1 = 0 of the first timer 71, the count time Tc2 = 0 of the second timer 73 (see FIG. 6), and the pulse count number Cs = 0 are set.
ST02: Various signals are read.

ST03: Check whether the engine 10 is stopped. If YES, the process proceeds to ST04. If NO, the engine 10 is determined to be operating and the process proceeds to ST21 in FIG. ST21 will be described later. For example, when the rotation speed of the engine 10 detected by the rotation sensor 68 is lower than a predetermined reference rotation speed (a minute rotation speed close to the stop state), the engine 10 is stopped. to decide.
ST04: It is checked whether the oil level switch 58 is on. If YES, the process proceeds to ST05, and if NO, the process proceeds to ST10. ST10 will be described later.

ST05: Check whether the count time Tc1 of the first timer 71 is 0. If YES, it is determined that the first timer 71 is in a stopped state, and the process proceeds to ST06. If NO, ST07 is determined to be counting. Proceed to
ST06: The first timer 71 is started.

  ST07: Check whether the count time Tc1 (elapsed time Tc1) has passed a predetermined first reference time Ts1. If YES, the process proceeds to ST08, and if NO, the process returns to ST02. When the time Tc1 during which the oil level switch 58 is kept on satisfies the condition that the first reference time Ts1 has elapsed, the determination is YES.

ST08: The first timer 71 is stopped.
ST09: After operating the alarm 63, the control by the controller 65 is terminated. The notification device 63 notifies that the actual level Lr of the lubricating oil Lu shown in FIG. 2B has decreased to the lower limit level L12.

ST10: Stop the first timer 71 or maintain the stopped state.
ST11: After resetting the count time Tc1 = 0, the process returns to ST02.

FIG. 6 is a control flowchart (No. 2) of the control unit according to the present invention, and shows the latter half of the control flow. The control unit 65 includes a counter 72 and a second timer 73 as shown in FIG.
ST21: Since the engine 10 is operating, it is checked whether or not there is a trigger pulse signal from the trigger pulse generator 66. If YES, the process proceeds to ST22, and if NO, the process proceeds to ST28. ST28 will be described later.
ST22: Since there is a trigger pulse signal, one pulse count number Cu is added.
ST23: It is checked whether or not the pulse count number Cu has reached a predetermined reference pulse number Cs. If YES, the process proceeds to ST24, and if NO, the process proceeds to ST33. ST33 will be described later.

ST24: It is checked whether or not the changeover switch 64 is on. If YES, the first mode is determined and the process proceeds to ST25. If NO, the second mode is determined and the process proceeds to ST27.
ST25: The alarm 63 is activated. The notification device 63 notifies that the actual level Lr of the lubricating oil Lu shown in FIG. 2B has decreased to the lower limit level L12.
ST26: After the ignition device 67 is stopped, the control by the control unit 65 is terminated. As a result, since high voltage electricity is not applied from the ignition device 67 to the ignition plug (not shown), the engine 10 stops.
ST27: After operating the alarm 63, the control by the controller 65 is terminated. The notification device 63 notifies that the actual level Lr of the lubricating oil Lu shown in FIG. 2B has decreased to the lower limit level L12.

ST28: Check whether the count time Tc2 of the second timer 73 is 0 or not. If YES, it is determined that the second timer 73 is in a stopped state, and the process proceeds to ST29. If NO, ST30 is determined to be counting. Proceed to
ST29: The second timer 73 is started.

  ST30: Check whether the count time Tc2 (elapsed time Tc2) has passed a predetermined second reference time Ts2 or not. If YES, the process proceeds to ST31, and if NO, the process returns to ST02 in FIG. The time Tc2 from when the trigger pulse generator 66 issues the first trigger pulse signal to the time when the next trigger pulse signal is issued (that is, the time interval Tc2 for receiving the trigger pulse signal) has passed the second reference time Ts2. When the condition of having been satisfied is satisfied, the determination is YES.

ST31: The second timer 73 is stopped.
ST32: After resetting the pulse count number Cu = 0, the process returns to ST02 in FIG.
ST33: The second timer 73 is stopped or kept in the stopped state.
ST34: After resetting the count time Tc2 = 0, the process returns to ST02 in FIG.

Here, the above description is summarized as follows.
The first timer 71 shown in FIG. 5 has a combined structure of ST05 to ST08, ST10, and ST11. The counter 72 shown in FIG. 6 has a combined structure of ST22 and ST23. The second timer 73 shown in FIG. 6 has a combined structure of ST28 to ST31, ST33, and ST34. ST03 shown in FIG. 5 constitutes engine operation determining means 74 for determining whether the engine 10 is stopped or operating.

  The oil level detection method by the oil level detection device 60 is characterized in that the first determination criterion and the second determination criterion for determining the actual level decrease of the lubricating oil Lu are set.

  The first judgment criteria are a condition that the engine 10 is stopped (ST03) and a condition that the time Tc1 in which the level decrease detection signal lasts reaches a preset first reference time Ts1 (ST04 and This is a criterion for determining that the actual level Lr of the lubricating oil Lu has decreased to the lower limit level L12 when the two conditions of ST07) are satisfied.

  The second determination criteria are a condition that the engine 10 is in operation (ST03) and a condition that the number of times Cu that has received the level decrease detection signal has reached a preset reference number Cs (ST21 to ST23). This is a criterion for determining that the actual level Lr of the lubricating oil Lu has decreased to the lower limit level L12 when the two conditions are satisfied.

  The oil level detection device 60 includes first determination means 75 (see FIG. 5) for determining the actual level decrease of the lubricating oil Lu based on the first determination criterion, and the lubricating oil Lu based on the second determination criterion. The second judgment means 76 (see FIG. 6) for judging the actual level decrease is provided.

First determination means 75 has a combined structure of ST03 and ST04 and first timer 71 (particularly ST07) shown in FIG.
That is, the first determination means 75 satisfies two conditions: a condition that the engine 10 is stopped and a condition that the time Tc1 in which the detection signal lasts reaches a preset reference time Ts1. The actual level Lr of the lubricating oil Lu is determined to have decreased to the lower limit level L12.

The second judging means 76 has a combined structure of ST03, ST21, counter 72 and second timer 73 shown in FIGS. The counter 72 has a combined structure of ST22 and ST23.
In other words, the second determination means 76 satisfies two conditions: a condition that the engine 10 is in operation, and a condition that the number of times Cu that has received the level decrease detection signal has reached a preset reference number Cs. When the condition is satisfied, it is determined that the actual level Lr of the lubricating oil Lu has decreased to the lower limit level L12.

Further, the second determination means 76 includes a reset means 77 having a combined structure of the second timer 73 (particularly ST30) and ST32 shown in FIG. Reset means 77, when the time interval Tc2 receiving the detection signal of the level reduction has reached the time interval Ts2 of a preset reference (second reference time Ts2), and resets the number of times Cu that has received the detection signal It is configured as follows.

  The combination structure of the changeover switch 64 shown in FIG. 4 and ST24 shown in FIG. 6 constitutes a switching means 78 for switching to the next first mode and second mode.

In the first mode, when the second determination means 76 determines that the actual level of the lubricating oil Lu has dropped (ST23), the alarm 63 is activated (ST25) and the engine 10 is stopped according to the determination (ST25). ST26), the control mode.
In the second mode, when the second determination means 76 determines that the actual level of the lubricating oil Lu has decreased (ST23), the alarm 63 is activated and the engine 10 is operating (operating state) according to the determination. Is a control mode in which the alarm 63 is operated (ST27).

Next, the operation of the oil level detection device 60 will be described in accordance with the control flow of FIGS. The operation will be described based on FIGS. 7 and 8 with reference to FIGS.
FIG. 7 is an operation diagram of the oil level detection device when the engine is stopped according to the present invention, and shows the operation of each part in a time chart with the horizontal axis as the elapsed time.

When the engine 10 is stopped and the oil level switch 58 is in the OFF state, the oil level is determined to be an allowable level (a level that has exceeded the lower limit level L12). For this reason, the alarm 63 is off (stopped).
Thereafter, when the oil level switch 58 is turned on, the first timer 71 is turned on and the timer count is started. When the time Tc1 (count time Tc1) during which the oil level switch 58 is kept on does not reach the preset reference time Ts1, the determination of the oil level remains at the allowable level.

  On the other hand, when the time Tc1 during which the oil level switch 58 is kept on reaches the reference time Ts1, the determination of the oil level is reversed to the lower limit level L12. For this reason, the notification device 63 is turned on (actuated) to notify that the actual level Lr of the lubricating oil Lu shown in FIG. 2B has decreased to the lower limit level L12. Note that the engine 10 remains stopped.

FIG. 8 is an operation diagram of the oil level detection device during engine operation according to the present invention, and shows the operation of each part in a time chart with the horizontal axis as elapsed time.
The changeover switch 64 is in the on state, and the engine 10 is operating. In this state, the oil level of the lubricating oil Lu is shaken by the engine vibration, so that the oil level switch 58 is repeatedly turned on and off. Only when the oil level switch 58 is turned on, the trigger pulse generator 66 generates a trigger pulse signal having a very small pulse width.

  After the oil level switch 58 is turned on only once, the oil level switch 58 is turned on again before the reference time interval Ts2 (second reference time Ts2) preset by the second timer 73 elapses. If not, the oil level determination remains at an acceptable level. For this reason, the alarm 63 is off (stopped), and the engine 10 remains operating.

  When the oil level switch 58 repeats the on / off operation for a shorter time Tc2 (counting time Tc2) than the reference time interval Ts2, the number of times of on operation Cu is counted and the number of times Cu is preset. When the reference number Cs is reached, the oil level determination is reversed to the lower limit level L12. For this reason, the notification device 63 is turned on (actuated) to notify that the actual level Lr of the lubricating oil Lu shown in FIG. 2B has decreased to the lower limit level L12. Moreover, the engine 10 stops.

As is clear from the above description, the operation of the oil level detection device 60 and the oil level detection method are summarized as follows.
As shown in FIGS. 1 and 2, the state of the oil surface of the lubricating oil Lu differs between when the engine 10 is stopped and when it is operating, and accordingly, the behavior of the float 54 is also different. That is, the oil level does not fluctuate while the engine 10 is stopped, and the vertical movement of the oil level is large while the engine 10 is operating.

  On the other hand, the oil level detection device 60 includes two determination means, that is, a first determination means 75 and a second determination means 76 shown in FIGS. 5 and 6 for determining the actual level decrease of the lubricating oil Lu. Prepared.

The first determination means 75 determines that the level actually falls when the engine 10 is stopped and the level drop detection signal (contact of the movable contact 55) continues for a certain time Ts1. Therefore, it is optimal for level detection while the engine 10 is stopped.
On the other hand, the second judging means 76 judges that the level is actually lowered when the engine 10 is in operation and receives a level lowering detection signal Cs a certain number of times (Cu ≧ Cs). Ideal for level detection during 10 operations.

  As described above, the actual level Lr of the lubricating oil Lu can be obtained by the simple configuration in which the oil level detection device 60 includes only the two determination means 75 and 76, both when the engine 10 is stopped and during operation. More accurate and reliable detection is possible.

In other words, in order to determine the actual level drop of the lubricating oil Lu, two determination criteria, ie, a first determination criterion and a second determination criterion are set.
The first criterion is that when the engine 10 is stopped and the level lowering detection signal (contact of the movable contact 55) continues for a certain time Ts1, it is determined that the level is actually lowering. It is most suitable for level detection while the engine 10 is stopped.
On the other hand, the second determination criterion is that when the engine 10 is in operation and the level decrease detection signal is received Cs a certain number of times (Cu ≧ Cs), it is determined that the level is actually decreased. Ideal for level detection during operation.

  As described above, since two determination criteria are set for the oil level detection method of the engine 10 so that the stop / operation of the engine 10 is used as a criterion, actual lubrication is performed both when the engine 10 is stopped and during operation. The level Lr of the oil Lu can be detected more accurately and reliably without malfunctioning.

Furthermore, as shown in FIG. 6, the second determination unit 76 includes a reset unit 77. Therefore, when the level determination during the operation of the engine 10 is performed by the second determination means 76, if the time interval Tc2 for receiving the detection signal is large, this detection signal is accompanied by the normal vertical movement of the oil level. It is determined that the signal is not a detection signal (for example, temporary noise), and the number Cu of times the detection signal is received can be reset.
By resetting in this way, the level Lr of the lubricating oil Lu during operation of the engine 10 can be detected more accurately and reliably.

  Furthermore, since the switching means 78 is provided, the alarm 63 is operated according to the level decrease detection signal and the engine 10 is stopped, and the alarm 63 is operated according to the level decrease detection signal. At the same time, the switching means 78 can switch to the second mode in which the operating state of the engine 10 is continued.

  That is, the switching means between the case where the engine 10 is automatically stopped and the case where the engine 10 is not automatically stopped when the level of the lubricating oil Lu in the crankcase 11 is lowered by a certain level or less using one type of oil level detection device 60. It can be switched at 78.

  Therefore, both the case where the engine 10 is automatically stopped and the case where the engine 10 is not stopped can be easily handled by only one type of oil level detection device 60. Since only one type of oil level detection device 60 needs to be prepared, the man-hours for managing the oil level detection device 60 can be reduced, and the manufacturing cost can be reduced. In addition, it is possible to cope with all types of loads (for example, working machines in all working forms) with one type of oil level detection device 60.

  Further, a part of the switching means 78 is constituted by a changeover switch 64 including a manual operation switch, and this changeover switch 64 is attached to the operation panel 61 of the engine 10. That is, the switching means 78 is configured by the manual operation switch 64. Therefore, the user can easily switch the first mode and the second mode by operating the switching means 78.

  Next, a modified example of the switching unit 78 will be described with reference to FIGS. In addition, about the engine 10 and the oil level detection apparatus 60 which are shown in the said FIGS. 1-8, it is the same structure, The same code | symbol is attached | subjected and the description is abbreviate | omitted.

FIG. 9 is a conceptual diagram of an engine and communication means provided with a switching means of a modification according to the present invention.
FIG. 10 is a control flowchart in the control unit provided with the switching means of the modification according to the present invention. The control flow shown in FIG. 10 is obtained by replacing ST24 of FIG. 6 with ST24A and ST24B of modifications.

As shown in FIG. 9, the switching means 80 of the modification includes a memory 81 for storing the mode switching data SW (see FIG. 10) provided in the engine 10, and the first mode and the second mode based on the mode switching data SW. And a switching unit 82 (see FIG. 10).
The memory 81 has a configuration in which the mode switching data SW can be written by an external communication unit, that is, the first communication unit 83 and the second communication unit 84, and includes, for example, a RAM (random access memory). More specifically, the control unit 65 includes a memory 81.

The first communication means 83 is an inspection / management machine used in the process of completion inspection and factory shipment after the manufacture of the engine 10 and the working machine equipped with the engine 10 is completed. For example, from a computer called a desktop computer Become.
The second communication means 84 is a sales management machine used in the market for the engine 10 and a work machine on which the engine 10 is mounted, and includes, for example, a computer called a notebook personal computer.

The mode switching data SW can be written in the memory 81 by the communication means 83 and 84 by the following procedure.
First, the cord 83a of the first communication means 83 or the cord 84a of the second communication means 84 is inserted and connected to the terminal 85 of the engine 10.
Next, the first communication unit 83 or the second communication unit 84 is operated, and the mode switching data SW is transmitted to the memory 81 via the control unit 65 in a predetermined communication mode. As a result, the mode switching data SW can be written and stored in the memory 81.

  Here, “mode switching data SW” is, for example, a flag used in the control flow of FIG. Hereinafter, the mode switching data SW is appropriately referred to as a flag SW. If the flag SW is “ON”, the first mode is selected. If the flag SW is “OFF”, the second mode is selected.

As shown in FIG. 10, switching unit 82 has a combined structure of steps ST24A and ST24B. The control flow of the control part 65 is demonstrated based on FIG.
ST23: It is checked whether or not the pulse count number Cu has reached a predetermined reference pulse number Cs. If YES, the process proceeds to ST24A, and if NO, the process proceeds to ST33 (see FIG. 6).
ST24A: The contents of the flag SW (mode switching data SW) are read from the memory 81.
ST24B: It is checked whether or not the flag SW is “ON”. If YES, the first mode is determined and the process proceeds to ST25. If NO, the second mode is determined and the process proceeds to ST27.

ST25: The alarm 63 is activated.
ST26: After the ignition device 67 is stopped, the control by the control unit 65 is terminated.
ST27: After operating the alarm 63, the control by the controller 65 is terminated.

  As described above, according to the modified example, the mode switching data SW is written in the memory 81 provided in the engine 10 by the external communication means 83 and 84, so that the mode switching data SW is based on the mode switching data SW. The switching unit 82 can automatically switch between the first mode and the second mode. For this reason, the user does not need to switch to the first mode and the second mode.

In the embodiment of the present invention, step ST21 shown in FIG. 6 may be configured so as to determine whether or not the oil level switch 58 is “inverted from off to on”. For this reason, the trigger pulse generator 66 is not necessarily required.
For example, every time the detection signal issued from the oil level switch 58 to the control unit 65 “inverts from an off signal to an on signal”, the control unit 65 executes an interrupt process. Can be determined.

Moreover, the structure which performs at least any one of step ST25 and step ST26 may be sufficient.
When ST25 is abolished, the engine 10 is only stopped at ST26.
When ST26 is abolished, only the alarm 63 is operated at ST25.
Whether or not to stop the engine 10 can be determined by the characteristics of the load on which the engine 10 is mounted, for example, the characteristics of various working machines.

As a configuration for notifying the fact that the actual level Lr of the lubricating oil Lu has decreased to the lower limit level L12 by the alarm 63, there are various types as described below.
(1) The alarm 63 comprising a display lamp is turned on.
(2) The indicator 63 composed of a display lamp is normally lit to indicate that the engine 10 is in a normal state, and when the actual level Lr decreases to the lower limit level L12, the indicator 63 is turned off or the display color is different. The light is emitted.
(3) An alarm 63 comprising an alarm such as a buzzer or a sound generator emits an alarm sound or an alarm message.

  According to the present invention, when the level of the lubricating oil Lu in the crankcase 11 is lowered more than a certain level using one type of oil level detection device 60, the engine 10 is automatically stopped and not stopped. The switching means 78 and 80 can be switched. Therefore, it is suitable for the engine 10 mounted on all kinds of loads (for example, working machines of all working forms).

It is sectional drawing which looked at the engine which concerns on this invention from the front. It is a principal part block diagram and action figure of the float type oil level detector which concern on this invention. It is a rear view of the engine which concerns on this invention. 1 is a circuit diagram of an oil level detection device for an engine according to the present invention. It is a control flowchart (the 1) of the control part concerning the present invention. It is a control flowchart (the 2) of the control part which concerns on this invention. It is an effect | action figure of the oil level detection apparatus in the engine stop which concerns on this invention. It is an operation view of the oil level detection device during engine operation according to the present invention. It is a conceptual diagram of the engine provided with the switching means of the modification concerning this invention, and a communication means. It is a control flowchart in the control part provided with the switching means of the modification which concerns on this invention. It is a block diagram of the oil level detection apparatus of the conventional engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Crankcase, 14 ... Crankshaft, 40 ... Oil scraping part, 50 ... Float type oil level detector, 54 ... Float, 55 ... Movable contact, 56 ... Fixed contact, 60 ... Oil level detection apparatus , 61 ... Operation panel, 62 ... Main switch, 63 ... Alarm, 64 ... Changeover switch, 75 ... First judgment means, 76 ... Second judgment means, 78 ... Switching means, 80 ... Switching means, 81 ... Memory, 82 ... switching unit, 83, 84 ... communication means from outside, Cs ... reference number (reference pulse number), Cu ... number of detection signals received (pulse count number), Lr ... actual level of lubricating oil, Lu ... lubrication Oil, L12 ... lower limit level, SW ... mode switching data (flag), Tc1 ... duration of detection signal, Ts1 ... reference time (first reference time).

Claims (3)

Work with an oil scooping part that scoops up the lubricating oil as the crankshaft rotates and supplies it to each sliding part in the crankcase, and a float type oil level detector that detects the level of the lubricating oil In the engine for a machine, the float type oil level detector is configured such that when the lubricating oil level is lowered to a preset lower limit level, the movable contact provided on the float comes into contact with the fixed contact, In the engine oil level detection device, which issues a detection signal for the decrease,
The engine oil level detection device operates a notification device in response to the detection signal and stops the engine, and operates the notification device in response to the detection signal and determines an operation state of the engine. provided in a second mode to proceed, and switching means for switching in accordance with the kind of the working machine, and a first determining means and the second determining means determines the level reduction of the real said lubricating oil,
The first determination means includes
A condition that the engine is stopped;
With the condition that the duration of the detection signal has reached a preset first reference time,
When the two conditions are satisfied, the actual level of the lubricant is determined to have decreased to the lower limit level,
The second determination means includes
A condition that the engine is operating;
With the condition that the number of detection signals received at an interval shorter than a preset second reference time has reached a preset reference number,
An engine oil level detection apparatus configured to determine that the actual level of the lubricating oil has decreased to the lower limit level when two conditions are satisfied.   2. The engine oil level detection device according to claim 1, wherein the switching means is a manual operation switch, and the manual operation switch is attached to an operation panel attached to the engine.   The switching means includes a memory for storing mode switching data in preparation for the engine and a switching unit for switching between the first mode and the second mode based on the mode switching data. 2. The engine oil level detection device according to claim 1, wherein said mode switching data can be written by said communication means.

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