JP7296056B2 - engine oil level detector - Google Patents

Description

The present invention relates to an engine oil level detection device for detecting the level of oil stored in an oil pan of an engine mounted on a vehicle.

Patent Document 1 discloses a diesel engine having a DPF that collects soot in exhaust gas, in which fuel is post-injected into a combustion chamber in an expansion stroke for regeneration of the DPF.

When post-injection is performed, the fuel adhering to the inner wall surface of the cylinder mixes with the oil in the oil pan. If the driving cycle is completed before the engine is warmed up, and if the vehicle is operated repeatedly for short periods of time, the oil temperature is low, so the fuel mixed in the lubricating oil does not evaporate, and the oil is diluted. , the oil level (oil surface level) increases. If the oil level continues to increase in this manner, it can affect the drivability of the engine.

Therefore, when it is determined that the oil level in the oil pan (height of the oil level) is equal to or higher than the upper limit value (permissible upper limit level), it is preferable to notify the effect and prompt oil replacement.

In Patent Document 1, an ultrasonic oil level sensor arranged in an oil pan of an engine mounted on a vehicle detects the level of oil (lubricating oil) stored in the oil pan (oil surface level). What does is disclosed. In addition, in Patent Document 1, when the upper limit value exceeds the detection limit of the oil level sensor, the detection limit of the oil level sensor is determined based on the driving characteristics of the vehicle that affect the change in the oil level. It is disclosed to estimate the oil level over a range exceeding .

JP 2014-227941 A

By the way, the oil level detected by the oil level sensor is affected by air mixed in the oil and thermal expansion of the oil, making it difficult to improve the robustness of the oil level detection value. Therefore, it is likely that the oil level detected by the oil level sensor is erroneously determined to have reached the upper limit, and an alarm is erroneously issued.

Specifically, when the temperature is low, the viscosity of the oil increases (the fluidity of the oil deteriorates), making it difficult for the air mixed in the oil to escape. Therefore, at low temperatures, the robustness is reduced due to the influence of air mixed in the oil. In other words, it is likely to be erroneously determined that the detected oil level has reached the upper limit even though the upper limit has not been reached if air is not mixed.

On the other hand, when the temperature of the oil is high, the viscosity of the oil is low (the fluidity of the oil is improved), so the degree of influence caused by mixing of air into the oil is low. However, when the temperature is high, the oil thermally expands to some extent and the fluidity improves, so that the oil level tends to rise and fluctuate easily. For this reason, even at high temperatures, it is likely that the detected oil level will be erroneously determined to have reached the upper limit even though the oil level has not actually reached the allowable limit. Become.

Therefore, if the engine is repeatedly stopped after being started for a short period of time, the oil level will not be detected correctly due to the influence of the air, and there is a possibility that the oil level will be misjudged. . On the other hand, if the oil remains hot for a long time, such as during long-distance driving, the oil level may not be detected correctly due to the thermal expansion of the oil and the decrease in oil viscosity, resulting in an erroneous judgment. be. In particular, erroneously judging that the oil level is above the upper limit even though the oil level has not reached the upper limit is undesirably prompted to change the oil unnecessarily.

The present invention has been made in consideration of the circumstances described above, and its object is to prevent the oil level sensor from repetitively operating at a low oil temperature or operating at a high temperature for a long period of time. To provide an engine oil level detection device capable of suppressing a situation in which an erroneous determination that the oil level detected by a is above an upper limit value is suppressed.

In order to achieve the above object, the present invention adopts the following solutions. That is, as described in claim 1,
An engine oil level detection device for detecting the level of oil stored in an oil pan of an engine mounted on a vehicle,
an oil level sensor provided in the oil pan for detecting the oil level in the oil pan;
a temperature sensor that detects the temperature of the oil in the oil pan;
a first determination means for determining whether or not the oil level detected by the oil level sensor is equal to or higher than a predetermined upper limit when the temperature detected by the temperature sensor is lower than or equal to a predetermined temperature;
second determination means for determining whether or not the oil level detected by the oil level sensor is equal to or higher than the upper limit when the temperature detected by the temperature sensor is higher than the predetermined temperature;
Notification for announcing an oil level warning when the first determining means determines that the oil level is equal to or higher than the upper limit value and the second determining means determines that the oil level is equal to or higher than the upper limit value. means and
It seems to be equipped with

According to the above-described solution method, when both the oil level when the oil temperature is low and the oil level when the oil temperature is high are equal to or higher than the upper limit value, an alarm regarding the oil level is issued. can suppress erroneous determinations due to the influence of air, and can suppress erroneous determinations due to expansion of oil and low viscosity at high temperatures.

A preferred embodiment based on the above solution method is as follows.
further comprising acceleration detection means for detecting acceleration acting on the vehicle;
The first determination means determines using the oil level detected by the oil level sensor when the acceleration detected by the acceleration detection means is equal to or less than a predetermined value.
(corresponding to claim 2). In this case, the oil level is detected in a state where the oil surface is not wavy, which is preferable in terms of performing the determination by the first determination means with high accuracy.

The first determination means may use an average value of a plurality of detection values detected by the oil level sensor (corresponding to claim 3). In this case, by using the average value of the oil levels acquired a plurality of times, it is preferable to reduce the influence of sudden large fluctuations in the oil level and to accurately perform the determination by the first determination means. become a thing.

further comprising acceleration detection means for detecting acceleration acting on the vehicle;
The second determination means determines using the oil level detected by the oil level sensor when the acceleration detected by the acceleration detection means is equal to or less than a predetermined value.
(corresponding to claim 4). In this case, the oil level is detected in a state where the oil surface is not wavy, which is preferable in terms of accurately performing determination by the second determining means.

The second determination means may use an average value of a plurality of detection values detected by the oil level sensor (corresponding to claim 5). In this case, the effect of abrupt and large fluctuations in the oil level is reduced, and this is preferable in terms of accurately performing determination by the second determining means.

According to the present invention, the oil level detected by the oil level sensor is equal to or higher than the upper limit when the oil temperature is repeatedly operated at a low temperature or when the oil temperature is high for a long time. It is possible to suppress a situation in which an erroneous determination is made.

BRIEF DESCRIPTION OF THE DRAWINGS The whole system diagram which shows embodiment of this invention and which shows schematic structure of an engine. FIG. 2 is a block diagram illustrating an example control system associated with oil level detection; FIG. 4 is a partial cross-sectional view showing how the oil level sensor is provided in the oil pan; FIG. 2 is a longitudinal sectional view showing a schematic configuration of an oil level sensor; A cross-sectional view taken along line VV in FIG. 4 . 4 is a time chart showing a control example of the present invention; 4 is a flowchart showing a control example of the present invention; FIG. 8 is a flow chart showing the contents of control in step Q3 shown in FIG. 7; FIG. FIG. 8 is a flow chart showing the contents of control in step Q4 shown in FIG. 7; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications or uses.

FIG. 1 shows a schematic configuration of an engine (engine body) 1 according to an embodiment. This engine 1 is a diesel engine that is transversely mounted in the front part of a vehicle and supplied with fuel containing light oil as a main component. The engine 1 includes a cylinder block 11 provided with a plurality of cylinders 11a (only one is shown), a cylinder head 12 arranged on the cylinder block 11, and a lubrication system arranged below the cylinder block 11. It has an oil pan 13 in which oil (hereinafter referred to as oil) is stored. A piston 14 is fitted in each cylinder 11a of the engine 1 so as to reciprocate, and a cavity defining a reentrant combustion chamber 14a is formed on the top surface of the piston 14. As shown in FIG. The piston 14 is connected to the crankshaft 15 via a connecting rod 14b.

The cylinder head 12 is provided with an injector 18 (fuel injection valve) for injecting fuel, and a glow plug 19 for warming the intake air when the engine 1 is cold to enhance the ignitability of the fuel. The injector 18 is arranged such that its fuel injection port faces the combustion chamber 14a from the ceiling surface of the combustion chamber 14a. The injector 18 basically injects fuel directly into the combustion chamber 14a near the top dead center of the compression stroke.

An intake passage 30 is connected to one side surface of the engine 1 so as to communicate with the intake port 16 of each cylinder 11a. On the other hand, the other side surface of the engine 1 is connected with an exhaust passage 40 for discharging burned gas (exhaust gas) from the combustion chamber 14a of each cylinder 11a. The intake passage 30 and the exhaust passage 40 are provided with a large turbocharger 61 and a small turbocharger 62 for supercharging intake air, which will be described later in detail.

An air cleaner 31 for filtering intake air is provided at the upstream end of the intake passage 30 . On the other hand, a surge tank 33 is arranged near the downstream end of the intake passage 30 . The intake passage 30 on the downstream side of the surge tank 33 is an independent passage that branches for each cylinder 11a, and the downstream end of each independent passage is connected to the intake port 16 of each cylinder 11a.

Between the air cleaner 31 and the surge tank 33 in the intake passage 30 are compressors 61a and 62a of the large and small turbochargers 61 and 62, and an intercooler 35 for cooling the air compressed by the compressors 61a and 62a. , and a throttle valve 36 for adjusting the intake air amount to the combustion chamber 14a of each cylinder 11a. The throttle valve 36 is basically fully opened, but is fully closed when the engine is stopped so as not to cause a shock.

The upstream portion of the exhaust passage 40 is constituted by an exhaust manifold having an independent passage branched for each cylinder 11a and connected to the outer end of the exhaust port 17, and a gathering portion where the independent passages gather. there is

On the downstream side of the exhaust manifold in the exhaust passage 40, a turbine 62b of the small turbocharger 62, a turbine 61b of the large turbocharger 61, and an exhaust gas for purifying harmful components in the exhaust gas are arranged in this order from the upstream side. A purification device 41 and a silencer 42 are provided.

This exhaust purification device 41 has an oxidation catalyst 41a and a DPF 41b, which are arranged in this order from the upstream side. The oxidation catalyst 41a and DPF 41b are housed in one case. The oxidation catalyst 41a has an oxidation catalyst supporting platinum or platinum added with palladium, etc., and promotes a reaction in which CO and HC in the exhaust gas are oxidized to produce CO2 and H2O. . This oxidation catalyst 41a constitutes a catalyst having an oxidation function. The DPF 41b collects PM such as soot contained in the exhaust gas of the engine 1. As shown in FIG. The DPF 41b is, for example, a wall-flow filter made of a heat-resistant ceramic material such as silicon carbide (SiC) or cordierite, or a three-dimensional mesh filter made of heat-resistant ceramic fibers. Incidentally, the DPF 41b may be coated with an oxidation catalyst.

The intake passage 30 and the exhaust passage 40 are connected by an EGR passage 51 . A downstream end of the EGR passage 51 opens to a portion of the intake passage 30 between the surge tank 33 and the throttle valve 36 . Further, the upstream end of the EGR passage 51 is opened to a portion of the exhaust passage 40 between the exhaust manifold and the small turbine 62 b of the small turbocharger 62 . The EGR passage 51 is provided with an EGR valve 51a for adjusting the amount of exhaust gas recirculated to the intake passage 30, and an EGR cooler 52 for cooling the exhaust gas with engine cooling water.

The large turbocharger 61 has a large compressor 61 a arranged in the intake passage 30 and a large turbine 61 b arranged in the exhaust passage 40 . The large compressor 61 a is arranged between the air cleaner 31 and the intercooler 35 in the intake passage 30 . On the other hand, the large turbine 61b is arranged in the exhaust passage 40 between the exhaust manifold and the oxidation catalyst 41a.

The small turbocharger 62 has a small compressor 62 a arranged in the intake passage 30 and a small turbine 62 b arranged in the exhaust passage 40 . The small compressor 62a is arranged in the intake passage 30 downstream of the large compressor 61a. On the other hand, the small turbine 62b is arranged upstream of the large turbine 61b in the exhaust passage 40 .

That is, in the intake passage 30, a large compressor 61a and a small compressor 62a are arranged in series from the upstream side. In the exhaust passage 40, a small turbine 62b and a large turbine 61b are arranged in series from the upstream side. These large and small turbines 61b, 62b are rotated by the exhaust gas flow. The large and small turbines 61b, 62b that are rotated operate the large and small compressors 61a, 62a connected thereto, respectively.

The small turbocharger 62 is relatively small, and the large turbocharger 61 is relatively large. That is, the inertia of the large turbine 61b of the large turbocharger 61 is greater than that of the small turbine 62b of the small turbocharger 62 .

An intake bypass passage 63 that bypasses the small compressor 62a is connected to the intake passage 30. As shown in FIG. The intake bypass passage 63 is provided with an intake bypass valve 63 a for adjusting the amount of air flowing through the intake bypass passage 63 . The intake bypass valve 63a is configured to be in a fully closed state (normally closed) when no power is supplied.

On the other hand, the exhaust passage 40 is connected to a small exhaust bypass passage 64 that bypasses the small turbine 62b and a large exhaust bypass passage 65 that bypasses the large turbine 61b. The small exhaust bypass passage 64 is provided with a regulating valve 64 a for adjusting the amount of exhaust gas flowing to the small exhaust bypass passage 64 . The large exhaust bypass passage 65 is provided with a waste gate valve 65 a for adjusting the amount of exhaust gas flowing to the large exhaust bypass passage 65 . Both the regulation valve 64a and the wastegate valve 65a are configured to be fully open (normally open) when no power is supplied.

The diesel engine 1 configured in this way is controlled by an electronic control unit (hereinafter referred to as ECU) 10 . The ECU 10 is composed of a CPU, a memory, a counter timer group, an interface, and a microprocessor having paths connecting these units. Signals from various sensors SW1 to SW8 are input to the ECU 10 in order to operate the engine 1 . SW1 is a water temperature sensor that detects the temperature of engine cooling water. SW2 is a boost pressure sensor that is attached to the surge tank 33 and detects the pressure of air supplied to the combustion chamber 14a. SW3 is an intake air temperature sensor that detects the temperature of intake air. SW4 is a crank angle sensor that detects the rotation angle of the crankshaft 15 . SW5 is an accelerator opening sensor that detects the accelerator opening corresponding to the amount of operation of an accelerator pedal (not shown) of the vehicle. SW6 is an upstream exhaust pressure sensor that detects the exhaust pressure on the upstream side of the DPF 41b. SW7 is a downstream side exhaust pressure sensor that detects the downstream side exhaust pressure of the DPF 41b. SW8 is a catalyst temperature sensor for detecting the temperature of the oxidation catalyst 41a.

The ECU 10 determines the state of the engine 1 and the vehicle by performing various calculations based on the detection signals from the sensors SW1 to SW8. ), and outputs control signals to the actuators of the various valves 36, 51a, 63a, 64a, 65a.

Thus, the engine 1 is configured to have a relatively low geometric compression ratio of 12 or more and 15 or less, thereby improving exhaust emission performance and thermal efficiency. I'm trying On the other hand, in this engine 1, torque is increased by the large and small turbochargers 61 and 62 described above to compensate for the low geometric compression ratio.

As a basic control of the engine 1, the ECU 10 determines a target torque (target load) mainly based on the engine speed and accelerator opening, and controls compression top dead center so as to generate this target torque. Fuel injection (main injection) is performed by the injector 18 in the vicinity. However, when the engine 1 is in a decelerating state, the ECU 10 executes fuel cut control to stop (prohibit) the main injection of fuel near the compression top dead center. The engine speed is determined by calculation based on the detection signal from the crank angle sensor SW4.

Furthermore, when the DPF regeneration condition is satisfied, the ECU 10 performs post injection that does not contribute to combustion (does not generate torque) by the injector 18 in the expansion stroke of the cylinder 11a in order to regenerate the DPF 41b. The post-injected fuel is supplied to the oxidation catalyst 41a together with the exhaust gas to cause an oxidation reaction. The oxidation reaction heat generated at this time raises the temperature of the exhaust gas supplied to the DPF 41b. The PM deposited on is burned off (the DPF 41b is regenerated).

Here, the DPF regeneration condition is a predetermined condition under which it can be determined that regeneration of the DPF 41b is necessary. In this embodiment, the amount of PM accumulated in the DPF 41b is evaluated (estimated) by the differential pressure ΔP between the exhaust pressure on the upstream side and the exhaust pressure on the downstream side of the DPF 41b. It is assumed that the regeneration condition for the DPF 41b is established. This DPF regeneration ends when the differential pressure ΔP falls below a predetermined lower limit value Y (<X) smaller than a predetermined value X as a regeneration condition. Therefore, when the PM accumulation amount M of the DPF 41b becomes equal to or greater than the predetermined value X and the DPF regeneration control is started, the DPF regeneration condition is established, the control is continued.

Next, an oil level detection device for the engine 1 that detects the oil level (oil level height) stored in the oil pan 13 of the engine 1 will be described.

The oil pan 13 is provided with an ultrasonic oil level sensor (hereinafter simply referred to as an oil level sensor) SW9 (not shown in FIG. 1) and an oil pump 72 (only shown in FIG. 2). The oil level sensor SW9 detects the oil level in the oil pan 13 by ultrasonically detecting the oil level in a detection tube 86, which will be described later. This detection is performed every predetermined cycle (for example, every second).

As shown in FIG. 3, the oil level sensor SW9 is arranged in the vehicle front-rear direction central portion in the oil pan 13, near one side in the vehicle lateral direction (left-right direction). The oil level sensor SW9 has an oil containing portion 81 and a base portion 82, as shown in FIGS.

The oil storage portion 81 stores oil that has flowed in from a first oil opening 83a, which will be described later. The oil containing portion 81 has a first labyrinth chamber dividing portion 83 , a second labyrinth chamber dividing portion 84 , a transmitter/receiver housing portion 85 , a detection pipe 86 and an air vent pipe 87 .

The first labyrinth chamber partitioning portion 83 and the second labyrinth chamber partitioning portion 84 are formed in a lidded cylindrical shape. The second labyrinth chamber partition 84 has a larger diameter than the first labyrinth chamber partition 83 . The transmitter/receiver housing portion 85 is formed in a lidded cylindrical shape. The transmitter/receiver accommodating portion 85 has a larger diameter than the second labyrinth chamber partitioning portion 84 . The first labyrinth chamber partitioning portion 83, the second labyrinth chamber partitioning portion 84, and the transmitter/receiver accommodating portion 85 are arranged in this order from above such that their axes are aligned with each other.

The transmitter/receiver housing portion 85 houses a transmitter/receiver 88 . This transmitter/receiver 88 is arranged to correspond to the detection tube 86 . The transmitter/receiver 88 transmits ultrasonic pulses toward the oil surface of the oil in the detection tube 86 and receives reflected waves reflected from the oil surface. The time from when the ultrasonic pulse is transmitted from the transmitter/receiver 88 toward the oil surface in the detection tube 86 to when the reflected wave reflected from the oil surface is received by the transmitter/receiver 88 is measured.

The detection tube 86 is formed in an elongated cylindrical shape. The detection tube 86 is arranged so that its lower end opening faces the inside of the transmitter/receiver accommodating portion 85 . The detection tube 86 projects upward from a portion of the ceiling wall of the transmitter/receiver housing portion 85 (also referred to as the “bottom wall of the second labyrinth chamber division portion 84”) slightly displaced from the center thereof. The detection tube 86 penetrates the ceiling wall of the first labyrinth chamber division 83 and the ceiling wall of the second labyrinth chamber division 84 (also referred to as "bottom wall of the first labyrinth chamber division 83").

A space defined by the ceiling walls of the first labyrinth chamber partition 83 and the second labyrinth chamber partition 84 and the detection tube 86 constitutes a first labyrinth chamber 89 . A space defined by the second labyrinth chamber dividing portion 84 , the ceiling wall of the transmitter/receiver housing portion 85 , and the detection tube 86 constitutes a second labyrinth chamber 90 . The first labyrinth chamber 89 and the second labyrinth chamber 90 constitute damping means for suppressing fluctuations in the oil level in the oil level sensor SW9.

A first oil opening 83 a is formed near the lower end of the portion of the peripheral wall of the first labyrinth chamber partition 83 opposite to the detection tube 86 . The oil in the oil pan 13 can flow into and out of the first labyrinth chamber 89 through the first oil opening 83a.

A partition plate 91 is provided between the first labyrinth chamber partition 83 and the detection tube 86 in the vicinity of the first oil opening 83a. The partition plate 91 partitions the inside of the first labyrinth chamber 89 together with the first labyrinth chamber partition 83 and the detection tube 86 . The partition plate 91 is in contact with the ceiling wall of the first labyrinth chamber partition 83 and the ceiling wall of the second labyrinth chamber partition 84 .

A second oil opening 84a is formed in a portion of the ceiling wall of the second labyrinth chamber partition 84 near the partition plate 91 and on the opposite side of the partition plate 91 to the first oil opening 83a. there is The oil in the first labyrinth chamber 89 can flow into and out of the second labyrinth chamber 90 through the second oil opening 84a.

A plurality of first resistance plates 92 extending radially inward are arranged at intervals on the inner peripheral surface of the peripheral wall of the first labyrinth chamber partition 83 . Each first resistance plate 92 is in contact with the ceiling wall of the first labyrinth chamber partition 83 and the ceiling wall of the second labyrinth chamber partition 84 . A gap is formed between each first resistance plate 92 and the detection tube 86 .

A plurality of second resistance plates 93 extending radially outward are arranged at intervals on the outer peripheral surface of the detection tube 86 . Each second resistance plate 93 is arranged between the circumferentially adjacent first resistance plates 92 . Each second resistance plate 93 is in contact with the ceiling wall of the first labyrinth chamber partition 83 and the ceiling wall of the second labyrinth chamber partition 84 . A gap is formed between each second resistance plate 93 and the peripheral wall of the first labyrinth chamber partition 83 .

The oil flowing into the first labyrinth chamber 89 from the first oil opening 83a meanders toward the second oil opening 84a through the labyrinth formed by the first resistance plate 92 and the second resistance plate 93. and flow. The oil in the first labyrinth chamber 89 flows into the second labyrinth chamber 90 through the second oil opening 84a. At this time, the oil flowing into the first labyrinth chamber 89 is resisted by the first resistance plate 92 and the second resistance plate 93 . As a result, high-frequency fluctuations in the oil level within the detection tube 86 are suppressed, and fluctuations in the oil level within the detection tube 86 are suppressed.

The configuration and action of the second labyrinth chamber 90 are substantially the same as those of the first labyrinth chamber 89 . That is, the oil that has flowed into the second labyrinth chamber 90 through the second oil opening 84a meanders through a labyrinth formed by resistance plates (not shown) in the second labyrinth chamber 90, and then flows into the transmitter/receiver housing. The oil flows into the transmitter/receiver accommodating portion 85 through a third oil opening 85 a formed in the ceiling wall of the portion 85 . At this time, the oil flowing into the second labyrinth chamber 90 is resisted by the resistance plate.

Also, the oil that has flowed into the oil containing portion 81 through the first oil opening 83 a passes through the first labyrinth chamber 89 , the second labyrinth chamber 90 , and the transmitter/receiver containing portion 85 and flows into the detection tube 86 . At this time, the oil level in the detection tube 86 fluctuates corresponding to the fluctuation in the oil level in the oil pan 13 . The oil level within the detection tube 86 substantially matches the oil level within the oil pan 13 .

The air vent pipe 87 is formed in an elongated cylindrical shape. The air vent tube 87 has a smaller diameter than the detection tube 86 . The air vent pipe 87 protrudes upward from the center of the ceiling wall of the first labyrinth chamber partition 83 to the opposite side of the detection pipe 86 so that its lower end opening faces the inside of the first labyrinth chamber 89 . is set.

A first cap member 94 is provided at the upper end of the air vent pipe 87 so as to cover the upper end. The first cap member 94 is formed in a closed cylindrical shape.

The oil that has flowed into the oil storage portion 81 through the first oil opening 83a passes through the first labyrinth chamber 89 and flows into the air vent pipe 87 . At this time, the oil level in the air vent pipe 87 fluctuates in accordance with the fluctuation in the oil level in the oil pan 13 . The oil level in the air vent pipe 87 substantially matches the oil level in the oil pan 13 .

Air contained in the oil that has flowed into the oil containing portion 81 passes through the air vent pipe 87 and is discharged from the lower end opening of the first cap member 94 to the outside of the oil containing portion 81 . The reason why the air contained in the oil is discharged to the outside of the oil containing portion 81 in this way is that when the air contains the oil, the ultrasonic pulse is diffusely reflected and the detection accuracy of the oil level sensor SW9 is lowered.

A second cap member 95 is provided at the upper ends of the detection tube 86 and the air vent tube 87 so as to cover the upper ends. The second cap member 95 is formed in a cylindrical shape with a lid and a bottom. The second cap member 95 prevents the oil in the oil pan 13 from flowing into the detection pipe 86 through its upper end opening.

An air opening 95 a is formed in the ceiling wall of the second cap member 95 . The air in the detection tube 86 can flow in and out of the oil storage portion 81 through the air opening 95a. The detection tube 86 and the first cap member 94 pass through the bottom wall of the second cap member 95 .

The base portion 82 supports the oil storage portion 81 . The base portion 82 is fixed to the bottom wall of the oil pan 13 . The base portion 82 has a base body 82a and a connector portion 82b.

The base body 82a is hollow. The base body 82a accommodates the circuit board 96. As shown in FIG. This circuit board 96 is electrically connected to the transceiver 88 . The circuit board 96 calculates the distance between the transmitter/receiver 88 and the oil level in the detection tube 86 based on the time measured by the transmitter/receiver 88 between the transmission of the ultrasonic pulse and the reception of the reflected wave. (calculate). Thereby, the oil level in the detection tube 86 is detected.

The connector portion 82b protrudes outward from the side wall of the base body 82a. The connector portion 82b is hollow. The connector portion 82b accommodates the connector 97. As shown in FIG. This connector 97 electrically connects the circuit board 96 and the ECU 10 .

A plurality of ribs 98 are formed on the outside of the oil containing portion 81 .

The oil pump 72 supplies and circulates the oil stored in the oil pan 13 to the lubrication parts of the rotating and sliding parts of the engine 1 . The oil pump 72 is driven by a chain (not shown) by the crankshaft 15 to pump oil. The oil pump 72 configured in this way is controlled by the ECU 10 mainly based on the temperature of the engine cooling water, the engine speed and the engine load.

FIG. 2 shows an example of a control system for determining whether or not the oil level has reached or exceeded a predetermined upper limit value based on the detection result of the oil level. Of the various sensors and devices connected to the ECU 10, only those related to the oil level are shown in FIG. That is, in FIG. 2, the various sensors SW1 to SW8 connected to the ECU 10 are omitted, and the various devices (18, 19, 36, 51a, 63a, 64a, 65a and VVM 71) are omitted. be.

In FIG. 2, SW9 is the aforementioned ultrasonic oil level sensor. SW10 is a vehicle speed sensor that detects the vehicle speed. SW11 is an oil temperature sensor that detects the temperature of the oil in the oil pan 13, that is, the temperature of the oil. SW12 is a longitudinal G sensor that detects longitudinal acceleration acting on the vehicle (body). SW13 is a lateral G sensor that detects lateral acceleration acting on the vehicle (body). The ECU controls the oil pump 72 as well as the oil lamp 73 and the oil cooler 74 .

The oil lamp 73 is provided, for example, in a meter panel located in front of the driver's seat, and is lit when the amount of oil in the oil pan 13 reaches or exceeds an upper limit value, which will be described later. That is, the oil lamp 73 functions as warning means for prompting the driver to change the oil (functions as a warning lamp).

The oil cooler 74 is connected to the oil circulation path to prevent the temperature of the oil in the oil pan 13 from exceeding a predetermined temperature (80° C. in the embodiment). That is, when the oil temperature detected by the oil temperature sensor SW11 exceeds 80° C., the oil flow is controlled so that the oil pressure-fed by the oil pump 73 passes through the oil cooler 74, and the oil temperature reaches the predetermined temperature. It is controlled as follows. Such oil temperature control is performed by the oil temperature control section 10a of the ECU 10. FIG.

The ECU 10 determines whether or not the oil level has reached an upper limit value (whether or not the oil level has reached or exceeded the upper limit value) based on the result of detection of the oil level by the oil level sensor SW9. Then, when the oil level becomes equal to or higher than the upper limit, the oil lamp 73 is turned on.

The determination of whether the oil level has reached the upper limit will be described later, but basically, when it is determined that both the determination result for low temperature and the determination result for high temperature have reached the upper limit. Finally, it is determined that the oil level has reached the upper limit.

The detection of the oil level by the oil level sensor SW9 is always performed every predetermined cycle (for example, every second). On the other hand, among the detected oil levels, the oil level (sampling value) used to determine whether the oil level has reached the upper limit is when all of the following extraction execution conditions are satisfied: is limited to the value of The reason for setting each extraction execution condition is to stably detect the oil level.

The first extraction execution condition (1) is that the communication between the oil level sensor SW9 and the ECU 10 is normal. This is to prevent erroneous determination when the oil level sensor SW9 or the ECU 10 is in an abnormal state.

The second extraction execution condition (2) is that the oil supply pressure (discharge pressure, hereinafter referred to as oil pressure) from the oil pump 72 is under low control (low pressure control) to keep the oil pressure below a predetermined pressure. be. That is, when switching to low control or high control (high pressure control) for increasing the hydraulic pressure to a predetermined pressure or higher, the oil level fluctuates. Therefore, if the oil level average value is calculated for both the low control and the high control, the accuracy will be lowered and the calculation logic will be complicated. Also, on the high pressure side, the amount of oil circulated is large and the engine speed is mainly high, so the oil level fluctuates greatly and is not suitable for stable detection of the oil level.

A third extraction execution condition (3) is that the engine speed is 750 to 3000 rpm. That is, when the engine speed becomes high, aeration increases, and the oil level is disturbed by the rotation of the crankshaft and chain, which lowers the detection accuracy of the oil level. Note that the upper limit value (3000 rpm) of the engine speed is set based on the engine speed at the time of switching between the low control and the high control of the hydraulic pressure. On the other hand, the lower limit (750 rpm) is set based on the idle speed, for example.

A fourth extraction execution condition (4) is that the vehicle speed is 5 km/h or more. That is, if the oil level is detected when the vehicle is stopped, the accuracy of the oil level detection decreases when the vehicle is on an incline. On the other hand, when driving, the frequency of continuous driving on regular slopes is low, so the oil level detection accuracy does not decrease.

The fifth extraction execution condition (5) is that the oil temperature in the oil pan 13 is 20 to 80°C. That is, the range is set to include the oil temperature during short-distance, short-time driving, in which the driving cycle is completed before the engine 1 is completely warmed up. Here, when short-distance and short-time driving is repeated, the oil temperature is low, so the fuel mixed in the oil does not evaporate, the oil is diluted, and the oil level increases. On the other hand, if the oil temperature is too low, the viscosity and circulation characteristics of the oil become unstable. Therefore, the lower limit of the oil temperature (20° C.) is set based on the characteristics of the oil temperature rise during short-distance, short-time running, the running time, and the above-mentioned adverse effects. On the other hand, the upper limit (80° C.) is set based on the oil temperature during high speed running including medium speed.

The sixth extraction execution condition (6) is that the longitudinal acceleration acting on the vehicle is 0.08 G or less. That is, when the acceleration in the longitudinal direction increases, the fluctuation of the oil level increases, which is not suitable for stable detection of the oil level. In addition, the reason why it was set to "0.08 G or less" is that when the vehicle is running, the rate of acceleration in the longitudinal direction being 0.08 G or less is considerably high, and it has a large effect on the calculation of the average oil level value and the securing of parameters. because there is no

A seventh extraction execution condition (7) is that the lateral acceleration is 0.08 G or less. That is, when the acceleration in the lateral direction increases, the fluctuation of the oil level increases, which is not suitable for stable detection of the oil level. In addition, the reason why it was set to "0.08 G or less" is that when the vehicle is running, the rate of lateral acceleration being 0.08 G or less is considerably high, and it has a large effect on securing the parameters for calculating the oil level average value. because it does not affect Since the engine 1 is laterally mounted in the front part of the vehicle and the oil level sensor SW9 is arranged in the center part of the oil pan 13 in the longitudinal direction of the vehicle and near one side in the lateral direction of the vehicle, Acceleration in the lateral direction has a greater effect on fluctuations in oil level than acceleration in the longitudinal direction.

The extraction unit 10b in the ECU 10 extracts the oil level value detected by the oil level sensor SW9 when all of the extraction execution conditions (1) to (7) described above are satisfied. That is, the extraction unit 10b selects and removes the detection value when the oil level is unstable and the detection value when the oil level sensor SW9 cannot detect from the detection values of the oil level sensor SW9, and extracts the other detection values. do.

However, when the acceleration in the lateral direction is 0.08 G or more while the vehicle is running (for example, when the duration of the state in which the acceleration in the lateral direction is 0.08 G or more is less than 5 seconds) , the detection value of the oil level sensor SW9 is not extracted for 7 seconds from the time when it becomes (returns) to less than 0.08 G again, even if the extraction condition is satisfied.

By the way, when the acceleration in the lateral direction becomes 0.08 G or more (for example, when the vehicle turns), the oil level in the oil level sensor SW9 fluctuates at a low frequency due to the unevenness of the oil in the oil pan 13, and the oil level The oil level in sensor SW9 fluctuates. Here, in the oil level sensor SW9, labyrinth chambers 89 and 90 (damping means) are provided to suppress high-frequency fluctuations of the oil level in the oil level sensor SW9. Although the oil in the SW9 does not flow out to the oil pan 13, a response delay of the oil level sensor SW9 occurs with respect to the low frequency fluctuation of the oil surface. Therefore, the lateral acceleration becomes less than 0.08 G again, and even if the oil in the oil pan 13 is no longer uneven, the oil level in the oil level sensor SW9 is almost stabilized (the oil level sensor SW9 is in a normal state). becomes). That is, even if the lateral acceleration becomes less than 0.08 G again, the detected value of the oil level sensor SW9 is affected by the lateral acceleration (low-frequency fluctuation of the oil level) for a while thereafter. Therefore, when the acceleration in the lateral direction becomes 0.08G or more while the vehicle is running, the detection value of the oil level sensor SW9 is not extracted for 7 seconds after it becomes less than 0.08G again. The reason why "7 seconds" is set is that the response delay time of the oil level sensor SW9 was about 7 seconds with respect to the low frequency fluctuation of the oil level when lateral acceleration was generated, when the experiment was conducted in advance. be.

Furthermore, when the lateral acceleration is 0.08 G or more and the direction is constant for 5 seconds or longer while the vehicle is running, the extraction unit 10b again becomes less than 0.08 G (recovered). For 30 seconds from time, even if the extraction condition is satisfied, the detection value of the oil level sensor SW9 is not extracted.

By the way, when the lateral acceleration is 0.08 G or more and the direction is constant for a relatively long period of time (for example, when the vehicle is turning in a constant direction for a relatively long period of time), in particular, When the oil level in the oil pan 13 approaches or reaches the L level, which will be described later, the oil level sensor SW9 is exposed from the oil due to the deviation of the oil in the oil pan 13, and the oil in the oil level sensor SW9 reaches the first opening. The air flows out from 83a to the oil pan 13 and flows into the oil level sensor SW9. At this time, the lateral acceleration becomes less than 0.08 G again, and even if the oil in the oil pan 13 is no longer uneven, the oil will flow into the oil level sensor SW9 again and the oil level will be almost stabilized (oil It takes time until the level sensor SW9 becomes normal. Therefore, when the vehicle is running and the lateral acceleration is 0.08 G or more and the direction is constant for 5 seconds or more, the oil level will be maintained for 30 seconds from the time when it becomes less than 0.08 G again. The detected value of sensor SW9 is not extracted. The reason why "30 seconds" was set is that, according to experiments conducted in advance, it took about 30 seconds for the oil level sensor SW9 to return to a normal state when all the oil in the oil level sensor SW9 had flowed out. be. Also, this "30 seconds" includes the response delay time (7 seconds) of the oil level sensor SW9.

As described above, when the extraction condition is satisfied, the extraction unit 10b detects that the detection value of the oil level sensor SW9 is less than 0.08 G when the lateral acceleration becomes 0.08 G or more. Detected within 7 seconds from the time the acceleration was turned on, and when the lateral acceleration was 0.08 G or more and the direction was constant for 5 seconds or more, it became less than 0.08 G again. Extract anything other than what is detected between time and 30 seconds.

The ECU 10 further includes a first averaging processing section 10c, a first determination section 10d, a second averaging processing section 10e, a second determination section 10f, and a final determination section 10g.

The first averaging processing section 10c and the first determination section 10d are for determination at low temperatures. That is, when the oil temperature detected by the oil temperature sensor SW11 is below a predetermined temperature (50° C. in the embodiment), the first averaging processing unit 10c performs A plurality (for example, about 10) of oil level values are obtained and the average value thereof is obtained. The average value at low temperature is taken as the final oil level value for low temperature.

The first determination unit 10d compares the average value at the low temperature acquired by the first averaging processing unit 10c with a preset upper limit value. As a result of this comparison, when the average value at low temperature is equal to or higher than the upper limit value, the first determination unit 10d determines that the oil level is abnormal. In the embodiment, the first determination unit 10d determines that the oil level is abnormal when the average value at low temperature is equal to or higher than the upper limit even once. Although different from the embodiment, in order to further improve robustness, the first determination unit 10d sets the , it can also be determined that the oil level is abnormal for the first time.

The second averaging processing section 10e and the second determination section 10f are for determination at high temperatures. That is, when the oil temperature detected by the oil temperature sensor SW11 exceeds the predetermined temperature (50° C. in the embodiment), the second averaging processing unit 10e performs A plurality of (for example, about 10) oil level values are acquired, and the average value thereof is obtained. This average value at high temperature is used as the final oil level value for high temperature.

The second determination unit 10f compares the average value at high temperature acquired by the second averaging processing unit 10e with the upper limit value. As a result of this comparison, when the average value at high temperatures is equal to or higher than the upper limit, the second determination unit 10f determines that the oil level is abnormal. In the embodiment, the second determination unit 10f determines that the oil level is abnormal for the first time when the average value at high temperature is equal to or higher than the upper limit value a plurality of times (three times in the embodiment). I'm trying to do it.

The final determination unit 10g finally determines that the oil level is abnormal when the first determination unit 10d determines that the oil level is abnormal and the second determination unit 10f determines that the oil level is abnormal. Judge that the level is abnormal. That is, when either one or both of the first determination unit 10d and the second determination unit 10f determine that it is normal (not abnormal), the determination result of the final determination unit 10g is normal. be.

When the final determination unit 10g determines that the oil level is abnormal, the oil lamp 73 is turned on. Of course, when the final determination unit 10g does not finally determine that the oil level is abnormal, the oil lamp 73 is extinguished.

Next, an example of oil level control by the ECU 10 will be described with reference to the time chart shown in FIG. Note that the time chart shown in FIG. 6 is based on the premise that all of the oil level extraction execution conditions described above are satisfied. Further, the oil temperature that separates the determination for low temperature and the determination for high temperature is 50°C. Furthermore, in the determination for low temperature, if it is determined that the oil level has reached the upper limit even once, it is determined that the oil level is abnormal. On the other hand, in the determination for high temperature, it is determined that the oil level is abnormal only when it is determined three times that the oil level has reached the upper limit.

(a) of FIG. 6 shows changes in the flag indicating whether or not the oil lamp 73 should be lit. When the flag is 0, the oil lamp 73 is extinguished. Further, when the flag is 1, the oil lamp 73 is lit (that is, the oil level reaches the upper limit).

FIG. 6(b) shows changes in the detected oil level (mean value shown) over the entire temperature range. Of this (b), the oil level (average value thereof) in a high temperature range exceeding 50° C. is used for determination by the second determination section 10f.

(c) of FIG. 6 shows changes in the oil level (mean value) detected only in the low temperature range where the oil temperature is 50° C. or lower. (d) of FIG. 6 shows changes in oil temperature.
Of this (b), the oil level (average value thereof) in a high temperature range exceeding 50° C. is used for determination by the second determination section 10f.

In FIG. 6, in the state up to time t1, the determination result for high temperature is that the oil level has exceeded the upper limit three times or more. However, until time t1, the oil level has never exceeded the upper limit as a result of determination for low temperature, so the flag remains at 0.

At time t2, which is a short time after time t1, the low temperature determination result indicates that the oil level is equal to or higher than the upper limit. As a result, it is finally determined that the oil level has exceeded the upper limit value, and the flag is set to 1 (the oil lamp 73 is lit). Once the oil lamp 73 is turned on, the oil lamp 73 continues to be turned on while the engine 1 is in operation unless the oil in the oil pan 13 is replaced by maintenance or inspection later.

Next, an example of oil level control by the ECU 10 will be described with reference to flowcharts shown in FIGS. 7 to 9. FIG. Incidentally, in the following description, Q indicates a step.

First, the main flowchart shown in FIG. 7 will be described. In Q1, signals from various sensors shown in FIG. 2 are read. Next, in Q2, it is determined whether or not the oil temperature detected by the oil temperature sensor SW11 is equal to or lower than a predetermined temperature (50° C. in the embodiment). When the determination in Q2 is YES, determination of the first oil level for low temperature is performed in Q3, as will be described later. Further, when the determination in Q2 is NO, determination of the second oil level for high temperature is performed in Q4, as will be described later.

After Q3 or Q4, the process is shifted to Q5. In this Q5, it is determined whether or not the determination result in Q3 and the determination result in Q4 are each determined to be abnormal. If the determination in Q5 is YES, it is finally determined in Q6 that the oil level is abnormal. After this Q6, in Q7, the driver is notified that the oil level is abnormal (notification by turning on the oil lamp 73). After passing through Q7, the control is terminated as it is (the oil lamp 73 remains illuminated while the engine 1 is operated until the oil is changed).

When the determination in Q5 is NO, it is finally determined in Q8 that the oil level is normal. After passing through Q8, the oil lamp 73 is extinguished. Moreover, when Q8 is passed, the process returns to Q1, and the control described above is executed again. The processing of Q5 to Q8 described above corresponds to the processing of the final determination section 10g in FIG.

Next, the flowchart of FIG. 8 showing the contents of control in Q3 of FIG. 7 will be described. First, in Q11, the oil level is detected a predetermined number of times (NA times, for example, NA=10 times). After that, in Q12, the average value of the oil level for the predetermined number of times detected in Q11 is calculated. After that, in Q13, the oil level averaged in Q12 is set as the final oil level for judgment. The processing in Q11 corresponds to the processing of the extraction unit 10b in FIG. Further, the processing of Q12 and Q13 corresponds to the processing of the first averaging processing section 10d in FIG.

After Q13, it is determined in Q14 whether the final oil level set in Q13 is equal to or higher than the upper limit value. If the determination in Q14 is YES, in Q15 whether or not the number of times the oil level exceeds the upper limit exceeds a predetermined number of times NB (in the embodiment, NB=1 time, but may be a plurality of times). is determined. If the determination in Q15 is YES, it is determined in Q16 that the oil level is abnormal at low temperatures.

When the determination in Q15 is NO, or when the determination in Q14 is NO, the process goes to Q17. At Q17, it is determined that the oil level at low temperature is normal. The determination results of Q16 and Q17 are used in the process of Q5 in FIG. Note that the processing of Q14 to Q17 corresponds to the processing of the first determination unit 10d in FIG.

Next, the flowchart of FIG. 9 showing the contents of control in Q4 of FIG. 7 will be described. First, in Q21, the oil level is detected a predetermined number of times (MA times, for example, MA=10 times). After that, in Q22, the average value of the oil level for the predetermined number of times detected in Q21 is calculated. After that, in Q23, the oil level averaged in Q22 is set as the final oil level for judgment. The processing in Q21 corresponds to the processing of the extraction unit 10b in FIG. Also, the processing of Q22 and Q23 above corresponds to the processing of the second averaging processing section 10e in FIG.

After Q23, it is determined in Q24 whether the final oil level set in Q23 is equal to or greater than the upper limit. When the determination in Q24 is YES, in Q25, the number of times the oil level reaches or exceeds the upper limit is a predetermined number of times MB (in the embodiment, MB=3 times, but the number of times may be 1, 2, or 4 or more). It is determined whether or not the limit (which may be present) has been exceeded. If the determination in Q25 is YES, it is determined in Q26 that the oil level is abnormal at high temperatures.

When the determination in Q25 is NO, or when the determination in Q24 is NO, the process goes to Q27. In Q27, it is determined that the oil level at high temperature is normal. The determination results of Q26 and Q27 are used in the process of Q5 in FIG. The processing of Q24 to Q27 corresponds to the processing of the second determination section 10f in FIG.

Here, by using the average value of a plurality of sampled oil levels as the oil level to be compared with the upper limit value, disturbances during running that fluctuate the oil level (for example, acceleration in the longitudinal direction, acceleration in the lateral direction, etc.) excludes the effects of In other words, after running for a certain period of time, the frequency of occurrence of forward acceleration and rearward acceleration, and the frequency of occurrence of leftward acceleration and rightward acceleration, become almost the same. Fluctuations in the oil level due to

Although the embodiment has been described above, the present invention is not limited to this and includes, for example, the following cases. The fuel of the engine 1 is not limited to a fuel mainly composed of light oil, and is not particularly limited to a fuel such as alcohol fuel (for example, ethanol fuel). Also, the engine may have a GPF (gasoline particulate filter) in the exhaust passage (the oil level may become abnormal when post-injection is performed to regenerate the GPF). The notification means for notifying that the oil level is abnormal is not limited to a lamp, but may be another visual appeal (for example, a character display) or an auditory appeal such as a buzzer.

The boundary temperature for dividing the oil level abnormality determination between low temperature and high temperature is not limited to a constant temperature such as 50° C., but may be set as a certain temperature range (eg, 45° C. to 60° C.). That is, the oil level detected when the temperature is lower than the lowest temperature (for example, 45°C) of the above temperature range is used for low temperature determination, and the oil level detected when the temperature is higher than the maximum temperature (for example, 60°C) of the above temperature range. can also be used as a judgment for high temperature. In this case, the oil level detected in the above temperature range (for example, 45° C. to 60° C.) is not used for judging abnormality of the oil level. Separating the low temperature and the high temperature with such a temperature range is preferable in order to sufficiently improve the robustness of the detected oil level. The objectives of the present invention are not limited to those expressly stated, but implicitly include those that are preferred or expressed as advantages.

INDUSTRIAL APPLICABILITY The present invention is suitably applied to, for example, a diesel engine having a DPF in the exhaust passage.

1: Engine 10: ECU
10a: Oil temperature control section 10b: Extraction section (extraction of oil level)
10c: First averaging processor (for low temperature)
10d: First judgment part (for low temperature)
10e: Second averaging unit (for high temperature)
10f: Second judgment part (for high temperature)
10g: final determination unit 13: oil pan 14a: combustion chamber 18: injector (fuel injection valve)
41b: DPF
73: Oil lamp (informing means)
SW9: Oil level sensor SW11: Oil temperature sensor

Claims (5)

An engine oil level detection device for detecting the level of oil stored in an oil pan of an engine mounted on a vehicle,
an oil level sensor provided in the oil pan for detecting the oil level in the oil pan;
a temperature sensor that detects the temperature of the oil in the oil pan;
a first determination means for determining whether or not the oil level detected by the oil level sensor is equal to or higher than a predetermined upper limit when the temperature detected by the temperature sensor is lower than or equal to a predetermined temperature;
second determination means for determining whether or not the oil level detected by the oil level sensor is equal to or higher than the upper limit when the temperature detected by the temperature sensor is higher than the predetermined temperature;
Notification for announcing an oil level warning when the first determining means determines that the oil level is equal to or higher than the upper limit value and the second determining means determines that the oil level is equal to or higher than the upper limit value. means and
An engine oil level detection device comprising: In claim 1,
further comprising acceleration detection means for detecting acceleration acting on the vehicle;
The first determination means determines using the oil level detected by the oil level sensor when the acceleration detected by the acceleration detection means is equal to or less than a predetermined value.
An engine oil level detection device characterized by: In claim 1 or claim 2,
The engine oil level detection device, wherein the first determination means uses an average value of a plurality of detection values detected by the oil level sensor. In any one of claims 1 to 3,
further comprising acceleration detection means for detecting acceleration acting on the vehicle;
The second determination means determines using the oil level detected by the oil level sensor when the acceleration detected by the acceleration detection means is equal to or less than a predetermined value.
An engine oil level detection device characterized by: In any one of claims 1 to 4,
The engine oil level detection device, wherein the second determination means uses an average value of a plurality of detection values detected by the oil level sensor.

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