JPH05163923A - Abnormality detecting device for oil level sensor - Google Patents

Abstract

PURPOSE:To accurately and speedily detect abnormality of a sensor based on running distance and number of stopping. CONSTITUTION:A liquid level sensor 34 is provided with a switch MSW which is set ON when a liquid level is normal while switched OFF when oil is decreased, and a switch LSW which is switched ON when the liquid level is lowered than a lower limit, while switched OFF when the level is upper than the lower limit. Abnormality judgment of the liquid level is executed every one second. A counter C is arranged for performing count-up (steps 104, 108, 112) under a condition that both the LSW and MSW are switched OFF. A counter D is arranged for performing count-up (step 128) when a vehicle is stopped (SPD=0). When the vehicle runs under a condition that both the LSW and MSW are switched OFF (Yes in step 116), and number of stoppings is not less than a specified number (Yes in step 116), the LSW and MSW are seemed to be not operated irrespective of oscillations of the oil level, and abnormality treatment is carried out (step 120).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting an abnormality in a liquid level sensor in an oil supply system for an internal combustion engine.

[0002]

2. Description of the Related Art In an oil supply system for automatically supplying oil to an internal combustion engine, an oil pump is provided in an oil passage between a reserve tank and an oil pan, and a liquid level sensor is provided in the oil pan and the reserve tank. By controlling the drive of the oil pump by the sensor in the pan, the oil liquid level in the oil pan is properly maintained. Then, in order to monitor the liquid level, two switches that are turned on and off at different liquid level positions are provided. The first switch is for detecting the upper liquid level, and the second switch is for detecting the lower liquid level. Then, for the abnormality diagnosis of the switches, it is determined whether or not the two switches have not detected the liquid surface for a predetermined traveling distance. That is, if the refueling device is normal, it is considered that at least one of the upper and lower liquid level detection switches will change due to the fluctuation of the liquid level after traveling a certain distance. It is determined to be abnormal when the predetermined traveling distance continues without detection of. See JP-A-3-130519.

[0003]

The predetermined traveling distance for determining the state in which the two switches do not change is set to, for example, 500 km, but the state of liquid level swaying the switches changes depending on the running state of the vehicle. To do. For example, when cruising on a highway, there is little fluctuation in the liquid surface, so the state of the switch may not change over a long distance.Therefore, if the predetermined value is not large, there is a possibility that it will be erroneously determined to be abnormal although it is normal. .. On the other hand, when driving in urban areas where there is a lot of acceleration and deceleration, the level of the switch should change immediately without traveling for a long distance because the level of the liquid sways significantly. Will take time.

An object of the present invention is to make it possible to accurately and quickly determine an abnormality regardless of the running state of a vehicle.

[0005]

According to the present invention, there is provided an abnormality detecting device for an oil supply device for an internal combustion engine for a vehicle, comprising: a first liquid level detecting means A for detecting a first liquid level position of oil;
Second liquid level detecting means B for detecting a second liquid level position having a liquid level different from that of the second liquid level, and the first liquid level detecting means A for not detecting the first liquid level position and the second liquid level. The first determination means C for determining the state in which the second liquid surface position is not detected by the surface detection means B, the means D for integrating the traveling distance of the vehicle during the determination of the state, and the means for integrating the vehicle being integrated. It comprises a means E for detecting the number of stops and a second discriminating means F for making an abnormality determination when the traveling distance is larger than a predetermined value and the number of stops is larger than the predetermined value.

[0006]

The first liquid level detecting means A detects the first liquid level position of the oil, and the second liquid level detecting means B detects the second liquid level position having a different liquid level from the first position. To do. First discriminating means C
Determines a state in which the first liquid level detection unit A does not detect the first liquid level position and the second liquid level detection unit B does not detect the second liquid level position. The mileage accumulating means D is
The traveling distance of the vehicle is integrated while it is determined that the first liquid level detection unit A has not detected the first liquid level position and the second liquid level detection unit B has not detected the second liquid level position. To do. The stop count detection means E detects the number of stoppages of the vehicle during the integration of the travel distance by the integration means D.

The second discriminating means F discriminates an abnormality when the traveling distance is larger than a predetermined value and the number of stops is larger than a predetermined value.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 2, reference numeral 10 denotes a main body of an internal combustion engine, 1
2 is an oil pan provided at the bottom of the oil pan. A strainer 14 is arranged in the oil pan 12. 16 is an oil gauge. Oil inlet 20 on the side wall of the oil pan 12
Is provided, and the oil introduction port 20 is connected to a discharge port 26-1 of an electric oil replenishment pump 26 via an oil supply pipe 22 and a check valve 24. 28 is a reserve tank, the bottom of which is connected to the suction port 26-2 of the oil supply pump 26.

The control circuit 30 is for automatically replenishing oil according to the present invention and is constructed as a microcomputer system. A water temperature sensor 32, a liquid level sensor 34, and a vehicle speed sensor 35 are connected to the control circuit 30 for performing oil supply control. The water temperature sensor 32 detects the temperature of the cooling water of the engine. The control circuit 30 is energized and operates when the ignition key switch 36 of the engine is on. The liquid level sensor 34 is a central sleeve 37.
And the annular float 3 fitted to the central sleeve 37
8 and an arm 40 that holds the central sleeve 37. In the central sleeve, as shown in the principle configuration of FIG. 3, a pair of switches (first liquid level detecting means) LSW and a switch (second liquid level detecting means) as reed switches are arranged along the height direction thereof. An MSW is provided while a magnet 42 is embedded within the annular float 38. The switch MSW located on the upper side is for controlling the liquid surface, and the magnet 42 faces the switch MSW in the normal liquid surface state. At this time, the position of the annular float 38 is determined by the upper stopper 43. When the oil level drops below the normal level, the magnet 42 in the annular float 38 switches the switch MS.
W is switched from on to off, which starts the oil supply. The switch LSW located on the lower side is for abnormality detection, and when the liquid level drops for some reason and the magnet 42 comes to the abnormal liquid level detection switch LSW, the switch LSW is turned on and the warning lamp 44 is turned on. .. The annular float 38 is prevented from descending below this position by the lower stopper 45. The liquid level sensor 34 is provided substantially at the center of the space inside the oil pan 12, and therefore, even if the liquid level is inclined due to the stopped state of the vehicle, the liquid level sensor 34 is installed at a location where the liquid level sensor 34 is installed. The influence of the tilt on the surface is reduced, and highly accurate measurement can be performed.

When the control circuit 30 determines that the oil supply condition has been satisfied, the oil supply pump 26 is intermittently driven a plurality of times as disclosed in Japanese Patent Laid-Open No. 3-130519 to supply oil, and an abnormality occurs according to the present invention. It is configured to make a diagnosis. For this reason, the control circuit 30 is connected on its output side to the oil supply pump 26 via the amplifier 48. Next, the operation of the control circuit 30 will be described with reference to the flowcharts of FIGS. FIG. 4 is a flowchart showing the outline of the oil pump supply operation in the main routine.
This routine is started when the ignition key switch 36 is turned on. In step 60, it is determined whether or not the crankshaft has made one revolution since the ignition key switch was turned on. When the crankshaft is rotating, the oil in the oil pan is agitated, so that the oil level cannot be accurately detected. In this embodiment, it is confirmed that the crankshaft has not made one revolution after the ignition key is turned on in order to judge the state in which the oil level capable of detecting the level is stationary. If cranking for one rotation is not performed, step 60 to step 62, 6
Then, the process proceeds to step 4, and it is determined whether or not the switches MSW and LSW are ON.
When the upper switch MSW for liquid level monitoring is ON, it is judged that the required amount of oil is present in the oil pan 12,
The following steps are bypassed. The upper switch MSW is OF
When the lower switch LSW is ON at F, the liquid level is lower than the lower limit liquid level, but this does not occur when refueling is performed normally. Therefore, at this time, step 66
Then, the abnormality processing such as lighting of the warning lamp 44 is performed.

When the liquid level is lower than the normal liquid level but higher than the lower limit liquid level, the upper switch MSW is OFF and the lower switch L
SW is also OFF, and the process proceeds to step 68, and
As in No. 30519, it is judged whether or not the liquid level is stable by means such as a difference between the water temperature at the time of the last stop and the current water temperature. If it is stable, the process proceeds to step 70 and the oil supply pump 26 Is operated for a predetermined time to refuel.
As described above, in this embodiment, the operation of the oil supply pump 26 is performed only once when the liquid level is insufficient when the engine is started.

Next, the diagnostic processing routine of the liquid level sensor 34, which is repeatedly performed every one second when the engine is operating, will be described. This diagnostic routine value is an abnormality when the traveling distance at which both switches LSW and MSW remain off during traveling of the vehicle is larger than a predetermined value. That is, since the liquid level fluctuates when the vehicle is running, the two switches LSW and MSW are turned on and off due to the fluctuation of the liquid level, and the two switches LSW and MSW do not remain off. So, when you run a predetermined distance, two switches
Since both LSW and MSW remain off, the switch LSW,
You can know the abnormality of MSW. FIG. 5 shows a routine executed at intervals of 1 second while the engine is operating. Step 1
At 00, it is determined whether the vehicle speed SPD is less than 70 km / h. When SPD> 70 km / h, the following routine is bypassed, and the mileage integration counter C in which both switches are OFF is not incremented. That is, SPD> 7
At 0 km / h, it is considered to be stable driving on highways, etc., and since the liquid level does not move, it is possible that both sensors remain OFF. In this case, do not move the counter C to make a diagnosis. It was designed to prevent the routine from working. As shown in FIG. 6, the ignition key switch 3
As long as 6 is ON, whether or not both switches are OFF is determined in the main routine that is repeatedly executed. Unless both switches LWS and MSW are OFF (that is, No in step 200 and in step 202). If not (No), the counter C is cleared at step 204. That is, the counter C represents the traveling distance when both the switches LWS and MSW remain OFF. When SPD ≦ 70 km / h, the routine proceeds to step 102, where the vehicle speed SPD measured by the vehicle speed sensor 35 is 60.
It is determined whether or not the range is up to 70 km / h. 60 ≦ SP
When D <70 km / h, the routine proceeds to step 104, where the counter increment is set to 4 × SPD. SPD <6
When it is 0 km / h, the routine proceeds to step 106, where the vehicle speed SPD is 5
It is determined whether or not the range is 0 to 60 km / h. 50 <S
When PD ≦ 60 km / h, the routine proceeds to step 108, where the counter increment is set to 7 × SPD. SPD ≦
When it is 50 km / h, the routine proceeds to step 110, where the vehicle speed SPD =
0, that is, it is determined whether or not the vehicle is stopped. When the vehicle is not stopped, the routine proceeds to step 112, where the counter increment is set to 10 × SPD. Steps 104, 108, 1
The process of 12 increases the increment of the mileage integration counter according to the vehicle speed and substitutes the mileage for the duration regardless of the change of the vehicle speed.

In step 114, the flag Y is cleared. That is, Y = 0 is set during traveling. This flag detects the transition time point of the vehicle from the running state (SPD> 0) to the stopped state (SPD = 0). In step 116, it is judged whether or not the counter value C ≧ 3,600,000 which is a substitute value of the traveling distance. Here, the predetermined value of C = 3,600,000 is converted to the traveled distance to be 200 to 500 km in steps 104 and 10.
The coefficient of increment of 8,112 is set appropriately. If C <3,600,000, bypass the error processing. C ≧
When it is 3,600,000, it is determined in step 118 whether or not the value of the counter D of the number of vehicle stops ≧ 5. Even if both switches MSW and LSW remain OFF and C ≧ 3,600,000 and D <5, no abnormality processing is performed. This is a simulation of the case where the liquid level does not sway, such as when driving on a highway, where the vehicle continues to run for a long time. In this case, even if both MSW and LSW remain off for a long time, the counter D Since it is not incremented and D ≧ 5 is not obtained in step 118, there is no erroneous determination as a switch failure.

When stopped, in step 110 SPD = 0
Therefore, the process proceeds to step 124 and whether Y = 0 or not, that is,
It is determined whether or not it is the time point when the traveling state is changed to the stop state. Y =
If it is 0, that is, SPD = 0 in the previous process, but SPD = 0 is determined this time, step 126
Then, Y = 1 is set and the counter D is incremented by 1 in step 128. In this way
If the number of stops reaches 5, if the counter value C ≧ 3,600,
If it is 000, Yes is determined in step 118 and step 12
The process proceeds to 0, and an abnormal process such as lighting of the warning lamp 44 is performed.

In the counter D, the switches MSW and LSW are both OFF
If not, it is cleared in step 204 of FIG. As a result, the counter D can be used to know the number of times the vehicle is stopped while the switches MSW and LSW remain off. In the above embodiment, the upper switch MSW is for oil supply control, and the lower switch LSW is for liquid level abnormality monitoring, but this is when the engine is a gasoline engine,
In case of diesel engine, the lower switch LSW is for oil supply control, and the upper switch MSW is for liquid level abnormality monitoring. This is because a diesel engine may overrun when the liquid level rises due to overfilling.

[0016]

According to the present invention, the state in which the respective liquid level detection positions by the detection means of both the first liquid level detection means and the second liquid level detection means are not continued is maintained for a predetermined distance, and the number of stops By determining whether the sensor is abnormal when the number of times is greater than or equal to a predetermined number of times, it is possible to prevent misjudgment when there is little fluctuation of the liquid surface and reduce the traveling time until it is determined to be abnormal as much as possible. Therefore, there is an effect that a quick and accurate abnormality diagnosis can be performed.

[Brief description of drawings]

FIG. 1 shows the configuration of the present invention.

FIG. 2 shows a configuration of an embodiment of the present invention.

FIG. 3 is a diagram showing a principle configuration of an oil level sensor.

FIG. 4 is a flowchart showing a refueling control routine.

FIG. 5 is a flowchart showing a switch abnormality diagnosis routine.

FIG. 6 is a flowchart showing a routine for clearing a counter.

[Explanation of symbols]

 10 ... Engine body 12 ... Oil pan 14 ... Strainer 22 ... Oil supply pipe 26 ... Oil supply pump 28 ... Reserve tank 30 ... Control circuit 36 ... Ignition key switch 34 ... Liquid level sensor 44 ... Warning lamp LSW, MSW ... Switch

Claims (1)

[Claims] 1. An oil supply device for an internal combustion engine for a vehicle, comprising: first liquid level detecting means for detecting a first liquid level position of oil;
A second position detecting second liquid level position different from the first position
First discriminating means for discriminating a state where the first liquid surface position is not detected by the liquid surface detecting means and the first liquid surface detecting means and the second liquid surface position is not detected by the second liquid surface detecting means. A means for accumulating the traveling distance of the vehicle during the determination of the state, a means for detecting the number of stops of the vehicle being accumulated, and a case where the traveling distance is greater than a predetermined value and the number of stops is greater than a predetermined value. An abnormality detecting device for an oil level sensor, which comprises a second determining means for performing abnormality determination.