JPS6296716A - Detecting device for engine oil shortage - Google Patents

Abstract

PURPOSE:To detect an engine oil shortage properly by giving an alarm when an engine oil level is below a predetermined value immediately after turning an ignition switch 'ON', or when engine oil pressure is below a predetermined value after engine start. CONSTITUTION:When engine oil has decreased down to a lower standard level, a head switch 5 comes to be located within a float 3 in an oil level sensor 1 provided within an oil pan, and a magnet 4 turns the lead switch 5 'OFF'. And one end of the lead switch 5 is earthed and the other end thereof is connected to a control circuit 7. And the control switch 7 is connected with an ignition device 12, a hydraulic pressure switch 9 to be turned 'ON' when pressure within an engine oil feed pipe is lower than a predetermined value, and an alarm lamp 10. Said connection is so made that the hydraulic pressure switch 9 will be turned 'ON' in a shortage of hydraulic pressure and the alarm lamp 10 will be lit. Also, an output terminal for an output level changing with said switch 9 turned 'ON' and 'OFF' is connected to the control circuit 7.

Description

[Detailed description of the invention] Flame Blood 1 The present invention relates to an engine oil shortage detection device.

1. In general, an engine mounted on a vehicle such as an automobile includes a large number of sliding parts. Friction occurs in each of these sliding parts, which causes power loss, wear, and engine seizure due to frictional heat. Engine oil is supplied to each sliding part in order to reduce frictional resistance in the sliding part and ensure smooth operation. In addition to the lubrication effect on the sliding parts, there is also a cooling effect on the sliding parts, a corrosion prevention effect, and an effect on keeping the combustion chamber airtight.

Engine oil is normally injected into an oil pan provided within the crankcase, and is supplied to each sliding part by an oil pump. The engine oil in the oil pan burns or leaks as the engine operates.
The amount of oil gradually decreases through vaporization. The lack of engine oil due to this reduction seriously impedes the above-mentioned lubricating and other functions, and paralyzes the engine's functions.

Therefore, it is extremely important to accurately detect whether or not the amount of engine oil is insufficient in order to maintain good engine operation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an engine oil shortage detection device that can accurately detect whether the amount of engine oil is insufficient.

The engine oil shortage detection device of the present invention detects that the engine oil level is below a first predetermined value immediately after turning on the ignition switch, or when it detects that the engine oil pressure is below a second predetermined value after starting the engine. It is characterized by generating an alarm at certain times.

1-x-1 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an engine oil shortage detection device for an on-vehicle internal combustion engine according to the present invention. In this device, an oil level sensor 1 is provided within an oil pan (not shown). The oil level sensor 1 consists of a magnet 4 installed in the center of an annular float 3 floating on the engine oil 2 surface, and a reed switch 5 fixed at a position corresponding to the reference level of engine oil in the oil pan. . When the engine oil decreases to the lower limit standard level, float 3
A reed switch 5 is located inside, and the magnet 4 turns off the reed switch 5. One end of the reed switch 5 is grounded, and the other end is connected to the control circuit 7.

The control circuit 7 is connected to an ignition device 12, an oil pressure switch 9 that is turned on when the pressure in the engine oil supply pipe is below a second predetermined value, and an alarm lamp 10. Further, a voltage Ve is supplied via the ignition switch 11. The oil pressure switch 9 is connected in such a way that it is turned on when there is insufficient oil pressure, and turns on the alarm lamp 10 when turned on. Further, the oil pressure switch 9 has an output end whose output level changes depending on whether it is turned on or off, and the output end is connected to the control circuit 7.

As shown in FIG. 2, the control circuit 7 includes a waveform shaping circuit 21 that shapes the waveform of the electric signal obtained from the primary coil 8 of the ignition coil of the ignition device 12, and a generation interval of the pulse signal output from the waveform shaping circuit 21. a counter 22 that measures the output level of the oil level sensor 1, the ignition switch 11, and the oil pressure switch 9, a level conversion circuit 23 that converts the output levels of the oil level sensor 1, the ignition switch 11, and the oil pressure switch 9; It consists of an input camosulator 24, a drive circuit 25 that drives the alarm lamp 10 to blink, a CPU 26 that performs digital calculations according to a program, a ROM 27 in which various programs and data are written in advance, and a RAM 28. counter 22, digital input camosulator 24,
Drive circuit 25, CPLI26, ROM27 and RAM2
8 are connected to each other by two input/output buses.

In such a configuration, information representing the engine speed is also transmitted from the counter 22 to the digital input camosulator 2.
4 supplies on/off information for each of the reed switch 5, ignition switch 11, and oil pressure switch 9 of the oil level sensor 1 to the CPU 26 via the input/output bus 29. Based on this information, the CPU 26 performs operations described below in accordance with clock pulses output from a clock generation circuit (not shown). The drive circuit 25 has a multivibrator (not shown) with an oscillation frequency of 1l-IZ, and operates the alarm lamp 1 at the oscillation frequency of the multivibrator in response to a blinking drive command output from the CPU 26.
The alarm lamp 10 is caused to blink by lighting up 0, and the blinking of the alarm lamp 10 is stopped in response to a blinking drive stop command.

Next, the operation of the above configuration will be explained using the CPLI2 shown in FIG.
This will be explained according to the operation flowchart of No. 6.

In the CPU 26, first, "O11" is set to the flag PIINT, which indicates the end of the oil pressure check when starting the engine, and the flag Alarll, which indicates the engine oil oil pressure abnormality.
is set and initialization is performed (step 51), and a blinking drive stop command is issued to the drive circuit 25 to turn off the lamp 10 (step 52).

Next, it is determined whether the ignition switch 11 is on or not (step 53), and when the ignition switch 11 is off, the flag FM is set to "1" and it is stored that the operating mode is the alarm mode (step 53). 54). When the ignition switch 11 is in the on state, it is determined whether the flag FM is equal to 1'' (step 55).

When FM=1, the flag FA for representing the elapsed state of the operating time and the flag Fs for representing the elapsed state of the stopped operation time are set to 1'' (step 56), and the ignition switch 11 is turned on. From 801
It is determined whether sec has elapsed (step 57).

When 801 seconds have elapsed, the variable n1 is made equal to O (step 58), the on/off status of the reed switch 5 of the oil level sensor 1 is read, and it is determined whether the reed switch 5 is on or not (step 59).

When the reed switch 5 is turned on, the value obtained by adding 1 to the variable n1 is set as a new variable n1 (step 60), and the value obtained by adding 1 to the variable n1 is set as the new variable n1.
It is determined whether or not is equal to 10 (step 61).

If n1≠10, it is determined whether 1011 seconds have elapsed since the previous on/off reading of the reed switch 5 (step 62). When 10 m5ec has passed, step 59 is executed again and the on/off status of the reed switch 5 is read.

When the reed switch 5 of the oil level sensor 1 is turned off, the oil level is below the reference level and there is a lack of oil, so the flag FM is set to "1" and the operation mode is memorized as the alarm mode (step 64), which flashes. A drive command is generated to drive circuit 25 (step 65). The drive circuit 25 causes the lamp 10 to blink at a frequency of 1H2 in response to the blinking drive command. After the blinking drive command is generated, it is determined whether the ignition switch 11 is on or not (step 66), and if the ignition switch 11 is off, a blinking drive stop command is issued to the drive circuit 25 (step 67).

If the ignition switch 11 is turned on, the lamp 10 continues to blink until the ignition switch 11 is turned off.

If FM=O in step 55, the operating mode is a non-alarm mode, so it is determined whether the flags FA, Fa are equal to O'' (steps 68 and 69>. In the steps described later, the engine operation time When the elapsed time is equal to or greater than the first predetermined time T+ (e.g. 1Qmin), the flag FA is set to 1'', and the elapsed time of the engine operation stop time is equal to or greater than the second predetermined time T2 (e.g. 1Qmin).
5m1n) or more, the flag Fs is set to "1". In this way, each time has elapsed, and if FA=1 and Fe=1, it is determined whether 3QIllSeC have elapsed since the ignition switch 11 was turned on (step 70). If B□m5ec has elapsed, the variable 02 is set equal to O (step 71), the on/off status of the reed switch 5 of the oil level sensor 1 is read, and it is determined whether the reed switch 5 is off or not (step 72).
. When the reed switch 5 is off, the value obtained by adding 1 to the variable n2 is set as a new variable 02 (step 73), and the value obtained by adding 1 to the variable n2 is set as a new variable 02 (step 73).
It is determined whether 2 is equal to 10 (step 74).
. If n2≠10, it is determined whether 10 m5ec has elapsed since the previous on/off reading of the reed switch 5 (step 75). When 101 seconds have elapsed, step 72 is executed again and the on/off status of the reed switch 5 is read.

If n2=10, the oil level is definitely below the reference level and there is a lack of oil, so step 64 is executed.

When the reed switch 5 of the oil level sensor 1 is turned on, the oil level is above the reference level and there is an appropriate amount of oil, so the flag FM is set to 0'' and it is stored that the operating mode is the non-alarm mode (step 77).

Further, when it is determined in step 61 that n+=10 by continuously detecting the ON state of the reed switch 5 10 times, in step 68 the flag FA is set to +i because the elapsed engine operating time is less than the first predetermined time T1. 0
When it is determined that it is equal to rr, further step 69
When it is determined that the flag Fs is equal to ``0'' because the elapsed engine stop time is less than the second predetermined time T2, step 77 is executed to set FM=O.
It is said that After that, it is determined whether the ignition switch 11 is on or not (step 78), and when the ignition switch 11 is on, the count value Ta of the time counter B (not shown) in the CPU 26 is counted down by a predetermined value. It is determined whether it is equal to (step 79).

Note that the count value TB of the time counter B is initially set to a second predetermined time T2 each time the ignition switch 11 is turned on. If day T≠O, engine speed Ne is 401', l), +11. It is determined whether it is smaller (step 80). If Te=o, flag Fa
is set to "1", and it is stored that the engine operation stop time has elapsed for a second predetermined time or more (step 81), and step 80 is executed. Ne<4Or, tl,
■ In the case of , it is assumed that the engine has stalled and step 78
is executed, and the time during which engine operation is stopped due to engine stalling is measured. In the case of Ne≧40 r, p, m, the flag FA1FB is set to “0”, the pressure detection flag Fp is set to “OII”, and the evening time counter A (not shown) in the CPU 26 is set to “0”. A first predetermined time T1 is set as a numerical value T^, and a time counter B
A second predetermined time T2 is set as the count value T days (
Step 82).

Next, it is determined whether the pressure detection flag Fp is equal to "OII" (step 83). If Fp = O, it is assumed that the oil pressure detection by the oil pressure switch 9 is impossible, and the flag PIINT is "1'' is determined (step 84), and if PIINT = O, it is determined whether the oil pressure switch 9 is on or not because the oil pressure check at the time of starting the engine has not been completed (step 85).

When the oil pressure is normal and the oil pressure switch 9 is off, a blinking drive command is issued to the drive circuit 25 (step 86).
A time counter C (not shown) in the CPU 26 determines whether a time period T3 during which the lamp 10 blinks three times has elapsed since the generation of the blinking drive command (step 87). If the time T3 has elapsed, a blinking drive stop command is issued to the drive circuit 25 (step 88), and the flag PIINT is set to "1", and it is stored that the oil pressure check at the time of engine startup has been completed. (
Step 89). The alarm lamp 10 flashes three times to indicate that the oil pressure at engine startup is normal.

Then, the engine speed Ne is 750 r, p, +e,
It is determined whether or not the state of being larger continues for 5 seconds or more (step 90). PIINT because the oil pressure check at engine startup has been completed in step 84.
When it is determined that = 1, or when it is determined in step 85 that the oil pressure switch 9 is on due to insufficient oil pressure, step 90 is immediately executed. Ne＞
If the states 750r, p, and m continue for 5 seconds or more, the pressure detection flag FP is set to 1'' and it is stored that the oil pressure can be detected (step 91).N
If the state of e〉750r, p, m, does not continue for more than 5 seconds, the engine speed Ne is 750r, p, m,
It is determined whether or not (step 92), Ne≦
750r, p, m, pressure detection flag Fp
is set to "0", and it is stored that the oil pressure cannot be detected (step 93). And flag A1
It is determined whether arm is equal to “1” (step 9
4) If Alarm = 1, it means that the engine oil pressure is abnormal, and a blinking drive command is issued to the drive circuit 25 (step 95). If Alarm=O, it is determined whether the count value TA of the time counter A is counted down by a predetermined value and is equal to "0" (step 96). That is, it is determined whether or not a first predetermined time T1 has elapsed since the start of operation of the engine. When TA=O, it is assumed that the first predetermined time T1 has elapsed since the start of engine operation, and the flag FA is set to "1" (step 97), and it is determined whether the engine rotation speed Ne is smaller than 4Or, p, m, or not. (Step 98).

When TA f-0, step 98 is executed immediately. If N e < 4 Or, I), n+, the engine operation is stopped, so it is determined in step 78 whether or not the ignition switch 11 is on.

If Ne is 40r, p, m, then the engine is in operation, and the steps after step 82 are executed again.

If it is determined in step 83 that Fp=1, the oil pressure switch 9 is in a state where it is possible to detect the oil pressure, so it is determined whether the oil pressure switch 9 has been on for 50 On+sec or more (9 steps). Oil pressure switch 9
If the on state continues for 500m5ecJJ,
The flag Alarm is displayed because the engine oil pressure is insufficient.
is set to 1'' to memorize the lack of oil pressure (step 1).
00), then step 92 is executed. If the oil pressure switch 9 does not remain on for 500 m5ec or more, step 92 is immediately executed.

Meanwhile, in step 78, the ignition switch 1
When it is determined that 1 is off, the flag FA is set to 1"
It is determined whether or not it is equal to (step 101). F.A.
When =1, it is determined in step 96 that the engine operating time until the ignition switch 11 was turned off was longer than the first predetermined time T1, so the engine oil temperature has risen sufficiently. The viscosity of the engine oil decreases due to a sufficient rise in engine oil temperature, and the engine oil can return from each part of the engine into the oil pan after the second predetermined time T2 has passed after the engine is stopped. Therefore, if FA=1,
It is determined whether the counted value TB of the time counter B is counted down by a predetermined value and is equal to 0 (step 102).
, when TB=0, the flag FB is set to "1" and it is stored that the engine operation stop time has elapsed for a second predetermined time or more (step 103). Therefore, the next time this routine is executed, steps 68 to 75 are executed, and the quality of the oil level is detected by determining whether the reed switch 5 of the oil level sensor 1 is on or off.

In such a detection device, as shown in FIG.
．． The ignition switch 11 is turned on at
When the engine is cranking, most of the engine oil is in the oil pan during the cranking period, so the oil level is detected. When the engine starts at time t2, engine oil is supplied to each sliding part by the oil pump, and the oil level in the oil pan decreases and becomes stable over time. The first predetermined time T1 is set to a time until the oil level becomes stable. When the engine is stopped at time t3, the engine oil gradually returns to the oil pan, causing the oil level to gradually rise.

When the second predetermined time T2 has elapsed from time t3, the oil level reaches a level that can be accurately detected, and the oil level is detected by the oil level sensor 1 from then on. Therefore, if the oil level is above the reference level as shown by the solid line a in Figure 4, the amount of oil is considered to be sufficient, and if the oil level is below the reference level as shown by the broken line in Figure 4, there is an oil shortage. It is.

Further, when the oil pressure of the engine oil is equal to or higher than the second predetermined value when starting the engine, the lamp 10 blinks for a predetermined time T3 to indicate that the oil pressure is normal; Status is 5
If it continues for more than 00 m5ec, the lamp 10 will flash to indicate that the oil pressure is insufficient.

As described above, the engine oil shortage detection device of the present invention detects whether or not the engine oil level is below the first predetermined value immediately after the ignition switch is turned on. Since the oil is in a static state just before it is supplied to moving parts, it is possible to accurately detect engine oil shortage. Further, by detecting whether the engine oil pressure is below the second predetermined value after the engine is started, it is possible to detect engine oil shortage even in a so-called dynamic state where engine oil is supplied to the sliding parts of the engine.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an engine oil shortage detection device according to the present invention, FIG. 2 is a block diagram showing a specific configuration of the control circuit of the device in FIG. 1, FIG. 3 is a flow diagram showing the operation of the CPU, and FIG. FIG. 4 is a diagram showing the relationship between the engine operating progress and the engine oil level. Explanation of symbols of main parts 1... Oil level sensor 5... Reed switch 7... Control circuit 9... Oil pressure switch 10... alarm lamp

Claims (1)

[Claims] level detection means for detecting whether the engine oil level is below a first predetermined value; pressure detection means for detecting whether the pressure in the engine oil supply pipe is below a second predetermined value; An alarm is issued when the level detection means detects that the engine oil level is below the first predetermined value or when the pressure detection means detects that the engine oil pressure is below the second predetermined value after the engine is started. An engine oil shortage detection device comprising: warning generating means for generating an alarm.