The present invention relates to an oil pan apparatus for storing oil for lubricating a lubrication target mechanism (e.g., engine block or automatic transmission mechanism).
In general, an oil pan apparatus of the above type is fastened to the underside of a lubrication target mechanism, and is configured so as to store oil in the internal space of an oil pan cover, which constitutes an outer cover for the oil pan apparatus. An oil-pan-attached machine (e.g., engine or automatic transmission device), which is equipped with the oil pan apparatus, is configured so that an oil pump takes in the oil from an oil intake port of an oil strainer, which is positioned in the oil pan apparatus, and supplies the oil to lubrication target members (e.g., gear, camshaft, cylinder, and piston) in the lubrication target mechanism. Further, the oil-pan-attached machine is configured so that the oil, which is supplied to the lubrication target members as described above, lubricates the lubrication target members, absorbs heat, which is generated due, for instance, to friction, and flows back to the oil pan apparatus from the lubrication target mechanism by gravitation.
A two-tank oil pan structure, which is disclosed, for instance, by Patent Reference 1, is widely known as a conventional oil pan structure.
[Patent Reference 1] Japanese Patent JP-A No. 278519/2003
In an oil pan apparatus having the two-tank oil pan structure which is disclosed by Patent Reference 1 (hereinafter referred to as the conventional technology), a partition plate is positioned within the internal space of an outer board that corresponds to the oil pan cover. The partition plate divides the internal space into two sections: a first chamber in which the oil strainer is located, and a second chamber which is adjacent to the first chamber.
The partition plate is provided with communication paths that permit the interchange of oil between the first and second chambers. Each communication path is provided with an open/close valve for permitting the passage of oil in the communication path in accordance with the oil temperature. In other words, the open/close valve is configured so as to control the interchange of oil through the communication paths between the first and second chambers in accordance with the temperature of the oil stored in the oil pan apparatus. More specifically, the open/close valve closes the communication paths when the oil temperature is lower than a predetermined temperature, and opens the communication paths when the oil temperature is not lower than the predetermined temperature, thereby permitting the passage of oil in the communication paths.
When the above conventional technology is used, the open/close valve closes at engine startup or in other situations where the oil temperature is low. Then, only the oil in the first chamber is supplied to the lubrication target mechanism and circulated between the lubrication target mechanism and oil pan apparatus. This increases the speed of oil temperature rise in the first chamber so that a warm-up operation may terminate early. Further, the open/close valve opens when the oil temperature is high. The oil stored in the oil pan apparatus is then entirely supplied to the lubrication target mechanism and circulated between the lubrication target mechanism and oil pan apparatus. This ensures that lubrication and cooling operations are properly performed for the lubrication target mechanism, and prevents the oil durability from deteriorating.
When the open/close valve becomes defective, the oil-pan-attached machine is not properly lubricated. If, for instance, the valve is stuck open (this failure is hereinafter referred to as “open valve failure”), the open/close valve remains open immediately after engine startup during which the oil temperature is low (and the oil in the oil pan apparatus can be entirely circulated between the lubrication target mechanism and oil pan apparatus). Therefore, the oil temperature in the first chamber does not readily rise. As a result, the warm-up operation does not terminate early. If, on the other hand, the valve is stuck closed (this failure is hereinafter referred to as a closed valve failure), the open/close valve remains closed (and only the oil in the first chamber can be circulated between the lubrication target mechanism and oil pan apparatus) even when the oil temperature in the first chamber becomes high after completion of the warm-up operation. Therefore, the oil temperature in the first chamber rises excessively, thereby incurring early oil deterioration or other problems.
As described earlier, the open/close valve is provided for the partition plate that is positioned in the internal space of the outer board. That is, the open/close valve is positioned within the oil pan apparatus. Therefore, the conventional technology cannot detect a defect in the open/close valve from the outside of the oil pan apparatus.
The present invention has been made to solve the above problem. It is an object of the present invention to provide an oil pan apparatus having a two-tank oil pan structure, which uses a simple structure to detect a defect in a valve mechanism that is positioned in a communication path for communication between a first chamber and a second chamber to control the interchange of oil in the communication path in accordance with the oil temperature in the oil pan apparatus. To achieve the above object, the oil pan apparatus according to the present invention is configured as described below.
(1) The oil pan apparatus includes an oil pan cover, which has an internal space for storing lubricating oil for a lubrication target mechanism, and an oil pan separator, which is positioned in the internal space so as to form a first chamber and a second chamber within the internal space, the second chamber being adjacent to the first chamber. The oil pan separator is provided with an oil communication path, which permits the interchange of oil between the first and second chambers. The oil communication path is provided with a valve mechanism, which controls the interchange of oil in the oil communication path between the first and second chambers in accordance with the operation (warm-up status, warm-up time, etc.) of the lubrication target mechanism.
The present invention is characterized by the fact that the oil pan apparatus includes an oil temperature sensor, which outputs a signal in accordance with the oil temperature in the first chamber and/or second chamber, and a judgment section, which judges from an output generated by the oil temperature sensor whether any abnormality exists in the valve mechanism.
As the valve mechanism, a solenoid valve mechanism, a hydraulically-operated valve mechanism, a pneumatic valve mechanism, a thermostat valve mechanism, a bimetal mechanism, or the like may be used.
In the configuration according to the present invention, which is described above, the valve mechanism controls the interchange of oil in the oil communication path between the first and second chambers in accordance with the operation of the lubrication target mechanism. The status of the interchange of oil in the oil communication path between the first and second chambers, which occurs in accordance with the operation of the lubrication target mechanism, may vary depending on whether an abnormality exists in the valve mechanism. Thus, oil temperature changes in the first chamber and/or second chamber may also vary depending on whether an abnormality exists in the valve mechanism. Therefore, the judgment section can judge from an output generated by the oil temperature sensor, which is based on the oil temperature in the first chamber and/or second chamber, whether an abnormality exists in the valve mechanism.
(2) The oil pan apparatus is characterized by the fact that it has the same configuration as described under (1) above. It is also characterized by the fact that an oil strainer is located at a bottom of the first chamber, and that the first chamber is open toward the lubrication target mechanism. The oil strainer constitutes an oil intake port from which an oil pump takes in oil to supply oil to the lubrication target mechanism.
In the configuration according to the present invention, which is described above, the oil pump runs during lubrication target mechanism operation so that the oil at the bottom of the first chamber is taken in from the oil strainer and supplied to the lubrication target mechanism. The oil supplied to the lubrication target mechanism lubricates the lubrication target mechanism and then flows back to the first chamber due to the configuration described under (2).
Further, as is the case with the configuration described under (1), the valve mechanism controls the interchange of oil in the oil communication path. Therefore, the oil in the second chamber may flow into the first chamber and be taken in by the oil strainer depending on the oil interchange control operation that the valve mechanism performs in accordance with the operation of the lubrication target mechanism. Furthermore, the oil flow from the first chamber to the second chamber may also vary with the oil interchange control operation that is performed by the valve mechanism.
As such being the case, the oil temperature change in the first chamber and/or second chamber may vary depending on whether an abnormality exists in the valve mechanism. Therefore, the judgment section can judge from an oil temperature sensor output, which is based on the oil temperature in the first chamber and/or second chamber, whether an abnormality exists in the valve mechanism.
(3) The oil pan apparatus is characterized by the fact that it includes the same oil pan cover and oil pan separator as described under (2) above. The oil pan apparatus is also characterized by the fact that it includes an oil temperature sensor, which is positioned in the second chamber to generate a signal in accordance with the oil temperature in the second chamber, and a judgment section, which judges from the output of the oil temperature sensor whether any abnormality exists in the valve mechanism.
In the configuration described above, the oil temperature sensor, which is used to check for an abnormality in the valve mechanism, may be mounted on the oil pan cover, which constitutes an outer cover of the oil pan apparatus, while the valve mechanism is positioned inside the oil pan apparatus. Thus, the valve mechanism can be checked for an abnormality while an extremely simple apparatus configuration is employed.
(4) Another feature of the present invention is that the following configuration is employed in addition to the configuration described under (3) above. The oil pan separator is open toward the lubrication target mechanism and provided with a concave section that forms the first chamber. A gap for forming a space that constitutes the second chamber is provided between a bottom plate of the oil pan separator and a bottom plate of the oil pan cover, which forms the bottom surface of the second chamber. A side plate for constituting the concave section together with the bottom plate of the oil pan separator is located above and connected to the bottom plate of the oil pan separator. A side plate of the oil pan cover that encloses the side plate of the oil pan separator is located above and connected to the bottom plate of the oil pan cover. A gap for forming a space that constitutes the second chamber is provided between the side plate of the oil pan separator and the side plate of the oil pan cover. The oil temperature sensor is mounted on the side plate or bottom plate of the oil pan cover.
In the configuration described above, the side plate and bottom plate of the oil pan separator on which the valve mechanism is mounted are positioned inside of and a predetermined distance away from the side plate and bottom plate of the oil pan cover, which constitutes the outer cover of the oil pan apparatus. It means that, in the configuration described above, the valve mechanism is positioned inside of and a predetermined distance away from the outer surface of the oil pan apparatus. Meanwhile, the oil temperature sensor, which is used to check for an abnormality in the valve mechanism positioned as described above, may be mounted on the oil pan cover, which constitutes the outer cover of the oil pan apparatus. Thus, the valve mechanism can be checked for an abnormality while an extremely simple apparatus configuration is employed.
(5) Another feature of the present invention is that the configuration described under (1) to (4) includes a thermosensitive transformation section, which is configured so as to vary its shape in accordance with the oil temperature. A wax-based thermostat, bimetal, shape-memory alloy, or the like that changes its shape due, for instance, to thermal expansion/contraction or phase transformation may be used as the thermosensitive transformation section.
Abnormalities in the valve mechanism described above differ from abnormalities in a solenoid valve mechanism, hydraulic valve mechanism, or other valve mechanism that is operated by using an external electrical signal or fluid pressure (the latter abnormalities can easily be judged directly from the outside when an abnormality in the electrical signal or pressure is detected), and cannot readily be judged directly from the outside. However, when the configuration according to the present invention is employed, abnormalities in the valve mechanism can easily be judged in accordance with the output from the oil temperature sensor.
(6) Another feature of the present invention is that the judgment section included in the configuration described under (1) to (5) checks the valve mechanism for an abnormality by examining an output signal generated by the oil temperature sensor and an output signal generated by a water temperature sensor. The water temperature sensor is provided in the lubrication target mechanism to output a signal in accordance with the temperature of cooling water for cooling the lubrication target mechanism.
The output signal generated by the water temperature sensor faithfully represents the operation of the lubrication target mechanism. When the valve mechanism is checked for an abnormality in accordance with the output signal from the water temperature sensor and the output signal from the oil temperature sensor, it is possible to formulate accurate abnormality judgment.
Embodiments of the present invention (embodiments that are considered to be the best by the applicant at the time of application of the present invention) will now be described with reference to the accompanying drawings.
<Engine Configuration Overview>
The engine block 20 contains a plurality of lubrication target members, including a piston 21, a crankshaft 22, and a camshaft 23. The lower end of the engine block 20 is connected to the oil pan apparatus 30, which stores the oil to be supplied to the above lubrication target members.
The lubrication system 40 is configured as described below so that the oil stored inside the oil pan apparatus 30 can be supplied to the lubrication target members.
An oil strainer 41, which includes an intake port 41a, is positioned within an internal space of the oil pan apparatus 30. The intake port 41a is used to take in oil that is stored in the internal space of the oil pan apparatus 30. The oil strainer 41 is connected by means of an oil pump 42 and a strainer flow path 43, which are provided in the engine block 20.
The oil pump 42 comprises a well-known rotary pump. Its rotor 42a is coupled to the crankshaft 22 so that the rotor 42a rotates together with the crankshaft 22. The oil pump 42 is connected via an oil transport channel 45 to the oil inlet of an oil filter 44, which is provided outside the engine block 20. The oil outlet of the oil filter 44 is connected to an oil supply channel 46, which is provided as an oil flow path toward the lubrication target members.
An oil pan cover 31 is a bathtub-shaped (concave) member that constitutes an outer cover of the oil pan apparatus 30. It is formed by pressing a steel plate and constructed of one piece. The oil pan cover 31 includes an oil storage section 31a, which is shaped like a bathtub to store oil in the internal space. At a peripheral border of a bottom plate 31a1 of the oil pan cover 31, which constitutes the bottom surface of the oil storage section 31a, a side plate 31a2 is provided and oriented obliquely upward as indicated in
An oil pan separator 32 is a member for partitioning the internal space of the oil storage section 31a into a first chamber 30a and a second chamber 30b. The first chamber 30a contains the oil strainer 41 and communicates with the cylinder block 20a. The second chamber 30b is adjacent to the first chamber 30a. The oil pan separator 32 is formed by injecting synthetic resin into a mold and constructed of one piece.
The oil pan separator 32 includes a bathtub-shaped oil storage section 32a, and is configured so that oil can be stored in an internal space of the oil storage section 32a. The intake port 41a of the oil strainer 41 is positioned at a predetermined short distance (e.g., approximately 10 mm) from a bottom plate 32a1 of the oil pan separator 32, which represents the lowest position in the oil storage section 32a. (The term “lowest position” refers to the lowest position that prevails in the direction of gravity when a predefined apparatus containing the engine 10 is placed on level ground and laterally viewed.) In other words, the internal space of the oil storage section 32a in the oil pan separator 32 forms the first chamber 30a in which the oil strainer 41 is positioned.
At a peripheral border of the bottom plate 32a1, a side plate 32a2 is provided and oriented obliquely upward as indicated in
The upper to middle area of the side plate 32a2 is provided with a plurality of upper communication holes 32c (e.g., circular holes approximately 8 to 10 mm in diameter or polygonal or oval holes similar in area to the circular holes) through which low-temperature, high-viscosity oil readily passes during a warm-up operation. The upper communication holes 32c are provided to adjust the oil levels in the first chamber 30a and second chamber 30b when the engine 10 shown in
The bottom section of the side plate 32a2 is provided with a thermostat valve apparatus 34. The thermostat valve apparatus 34 is through the side plate 32a2 and positioned nearly at the same height as the upper end of the intake port 41a of the oil strainer 41. The configuration of the thermostat valve apparatus 34 will now be described with reference to
<<Thermostat Valve Apparatus Configuration>>
The thermostat valve apparatus 34 includes a valve body 34b that is made of metal and filled with wax 34a. The valve body 34b includes: a valve disc 34b1, which has a through-hole at the center and substantially shaped like a circular disc; a main body section 34b2, which is substantially shaped like a cylindrical column and provided with a cavity that is filled with wax 34a; and a connection section 34b3, which is substantially shaped like a cylinder and used to connect the valve disc 34b1 to the main body section 34b2. A rod 34c is positioned inside the cylinder that is formed by the connection section 34b3. One end of the rod 34c is exposed to the cavity filled with wax 34a, and the other end is exposed to the outside of the valve body 34b from the through-hole at the center of the valve disc 34b1. The wax 34a, valve body 34b, and rod 34c are used to form a thermosensitive transformation section that can vary its shape in accordance with the oil temperature. The wax 34a, which constitutes a thermosensitive section of the thermosensitive transformation section, and the main body section 34b2, which is filled with the wax 34a, are enclosed by a housing 34d, which is a metallic member that is substantially shaped like a cylinder. The thermostat valve apparatus 34 is positioned in such a manner that the main body section 34b2 and housing 34d are positioned toward the first chamber 30a. A sealant 34e is inserted into the through-hole in the valve disc 34b1 for sealing purposes so that the wax 34a, which is filled into the valve body 34b, does not leak out of the valve body 34b.
The housing 34d is provided with a first chamber side opening 34d1, which is a through-hole. The first chamber side opening 34d1 permits the internal space of the housing 34d to communicate with an external space (first chamber 30a). One end of the housing 34d is provided with a through-hole 34d2. This through-hole 34d2 is positioned so that the main body section 34b2 of the valve body 34b, which is filled with the wax 34a, is exposed to the first chamber 30a. Further, the main body section 34b2 of the valve body 34b can move (slide) inside this through-hole 34d2.
The other end of the housing 34d is provided with a flange section 34f, which is shaped like a circular disc and extended outward. When bolts 35a and nuts 35b are tightened with the flange section 34f placed over the side plate 32a2 of the oil pan separator 32, the thermostat valve apparatus 34 is fastened to the side plate 32a2.
The inside of the flange section 34f is connected to a second chamber facing cover 34g, which is made of a plated member that is exposed toward the second chamber 30b. The second chamber facing cover 34g is provided with a second chamber side opening 34g1, which is a through-hole. The other end of the rod 34c, which was mentioned earlier, is fastened to the second chamber facing cover 34g. The second chamber facing cover 34g (and valve disc 34b1) are shaped so that the valve disc 34b1 cuts off the communication between the internal space of the housing 34d and the internal space of the second chamber facing cover 34g when the second chamber facing cover 34g comes into contact with the valve disc 34b1.
The internal space of the housing 34d is provided with a coil spring 34h that is positioned to surround the valve body 34b. One end of the coil spring 34h is in contact with the valve disc 34b1, and the other end is in contact with the aforementioned one end of the housing 34d.
The thermostat valve apparatus 34 is such that if the oil temperature in the first chamber 30a, which is in contact with the main body section 34b2 of the valve body 34b, is lower than a predetermined valve opening temperature, the communication between the first chamber 30a and second chamber 30b breaks when the second chamber facing cover 34g comes into contact with the valve disc 34b1 as indicated in
Due to the configuration described above, the thermostat valve apparatus 34 increases its valve opening ratio (the ratio of the current flow path cross-sectional area to the maximum flow path cross-sectional area of the oil communication path) in accordance with a temperature rise. The wax 34a expands in accordance with the oil temperature in the first chamber 30a that prevails near the thermostat valve apparatus 34. When the valve body 34b is placed at a position at which the force for pushing the valve body 34b toward the first chamber 30a due to wax expansion balances with the pushing force generated by the coil spring 34h, the status of the interchange of oil in the oil communication path varies with the oil temperature.
<Control System Configuration>
The crank position sensor 63 generates a narrow-width pulse each time the crankshaft 22 rotates 10°, and generates a wide pulse each time the crankshaft 22 rotates 360°. The water temperature sensor 64 detects the temperature of cooling water for cooling the engine 10, and outputs a signal that represents the cooling water temperature Tw. The oil temperature sensor 65a is mounted on the side plate 31a2 of the oil pan cover 31 from the outside and secured as indicated in
Referring again to
The operations performed by the oil pan apparatus 30 according to the present embodiment, which is configured as described above, will now be described.
Due to a negative pressure that is generated at the intake port 41a of the oil strainer 41 in the first chamber 30a during an operation of the oil pump 42 (see
After completion of the warm-up operation, the thermostat valve apparatus 34 opens as indicated in
As described earlier, the thermostat valve apparatus 34 is configured so that the valve opening ratio gradually increases with an increase in the temperature. Therefore, the valve opening ratio of the thermostat valve apparatus 34 is low and the inflow amount of low-temperature oil stored in the lower part of the second chamber is small immediately after the valve opening temperature is reached by the oil around the thermostat valve apparatus 34 with the warm-up operation terminated. Consequently, the low-temperature oil does not flow into the first chamber 30a in large quantities and become taken in via the intake port 41a of the oil strainer 41. As a result, it is possible to prevent the low-temperature oil from being supplied in large quantities to the lubrication target members to rapidly cool the lubrication target members.
<<Oil Temperature Changes>>
Changes in the oil temperature in the first chamber 30a (hereinafter referred to as the first chamber oil temperature) and changes in the oil temperature in the second chamber 30b (hereinafter referred to as the second chamber oil temperature) will now be described with reference to
(Normal State)
As indicated in
When the first chamber oil temperature subsequently reaches the valve opening temperature To_open of the thermostat valve apparatus 34 (it is assumed that the resulting elapsed time is to_open), the thermostat valve apparatus 34 begins to open, thereby invoking the interchange of oil in the oil communication path between the first chamber 30a and second chamber 30b. Consequently, the second chamber oil temperature begins to rise greatly as indicated by solid lines in
(Closed Valve Failure)
If, for instance, the sealant 34e for the thermostat valve apparatus 34 deteriorates so that the wax 34a, which is filled into the valve body 34b, leaks out of the valve body 34b, the thermostat valve apparatus 34, which is closed as indicated in
(Open Valve Failure)
If, for instance, any foreign matter is caught between the second chamber facing cover 34g and valve disc 34b1 of the thermostat valve apparatus 34 after termination of a warm-up operation during the operation of the engine 10, the thermostat valve apparatus 34 is left open as indicated in
<<Typical Failure Judgment Process>>
A concrete example of the above failure judgment process will now be described with reference to a flowchart in
First of all, the CPU 71 performs step 605 to acquire the initial oil temperature Too0, which is the second chamber oil temperature prevailing immediately after engine startup, in accordance with the output from the oil temperature sensor 65a.
Next, the CPU 71 performs step 610 to reset the count reached by a timer t and let the timer t start counting.
Next, the CPU 71 proceeds to step 615 and judges whether the initial oil temperature Too0 is lower than a predetermined temperature that is lower by a predetermined value ΔT0 than the valve opening temperature To_open of the thermostat valve apparatus 34 (Too0<To_open−ΔT0). As the predetermined value ΔT0, a numerical value greater than zero (e.g., a value between 0 and 20) can be selected as appropriate.
(A) If the initial oil temperature Too0 is lower than the predetermined temperature (when the query in step 615 is answered “Yes”), the engine 10 is cold started and being warmed up. Therefore, the CPU 71 proceeds to step 620 and waits until the elapsed time (the count reached by the timer t) reaches a predetermined value t1. As the predetermined value t1, an appropriate value is set in accordance with the initial oil temperature Too0 and a predefined table stored in the ROM 72 (see
When the elapsed time from engine startup is equal to the predetermined value t1 (when the query in step 620 is answered “Yes”), the CPU 71 proceeds to step 625 and acquires the second chamber oil temperature rise ΔT=Too−Too0 immediately after engine startup. Next, the CPU 71 proceeds to step 630 and judges whether the temperature rise ΔT is smaller than a predetermined value ΔT1.
If the temperature rise ΔT is not smaller than the predetermined value ΔT1 (if the query in step 630 is answered “No”), it is judged that the second chamber oil temperature Too is higher than the initial oil temperature Too0 by more than the predetermined value ΔT1 although the elapsed time has not reached the thermostat valve opening time to_open. In other words, it is judged that an open valve failure has occurred. The CPU 71 then proceeds to step 635 and illuminates the warning lamp 83 to indicate the occurrence of the open valve failure. Next, the CPU proceeds to step 695 and terminates the routine.
If, on the other hand, the temperature rise ΔT is smaller than the predetermined value ΔT1 (if the query in step 630 is answered “Yes”), no open valve failure has occurred. Therefore, the CPU 71 proceeds to step 640 and waits until the elapsed time reaches a predetermined value t2. As the predetermined value t2, an appropriate value is set in accordance with the initial oil temperature Too0 and a predefined table stored in the ROM 72. This appropriate value should be such that when a predetermined period of time elapses after the thermostat valve apparatus 34 opens with the first chamber oil temperature rendered higher than the valve opening temperature To_open of the thermostat valve apparatus 34, the interchange of oil may occur between the first chamber 30a and second chamber 30b to make the second chamber oil temperature Too sufficiently higher than the initial oil temperature Too0 (that is, the elapsed time has exceeded the thermostat valve opening time to_open). When the elapsed time is equal to the predetermined value t2 (when the query in step 640 is answered “Yes”), the CPU 71 proceeds to step 645, acquires the aforementioned temperature rise ΔT=Too−Too0 in accordance with the current second chamber oil temperature Too, and judges whether the temperature rise ΔT is not smaller than a predetermined value ΔT2.
If the temperature rise ΔT is not smaller than the predetermined value ΔT2 (if the query in step 650 is answered “Yes”), the CPU 71 proceeds to step 655 and judges that the second chamber oil temperature Too is raised by more than a predetermined value after the thermostat valve opening time to_open is exceeded by the elapsed time (that is, no closed valve failure has occurred in the thermostat valve apparatus 34). The CPU 71 then proceeds to step 695 and terminates the routine.
If, on the other hand, the temperature rise ΔT is smaller than the predetermined value ΔT2 (if the query in step 650 is answered “No”), it is judged that the second chamber oil temperature is hardly raised although the thermostat valve opening time to_open is exceeded by the elapsed time, that is, a closed valve failure has occurred. Therefore, the CPU 71 proceeds to step 660 and illuminates the warning lamp 83 to indicate the occurrence of the closed valve failure. Next, the CPU proceeds to step 695 and terminates the routine.
(B) If the initial oil temperature Too0 is not lower than the predetermined temperature (when the query in step 615 is answered “No”), the current engine startup operation is a hot start, which does not require any warm-up operation. Therefore, the thermostat valve apparatus 34 opens immediately after engine startup so that the interchange of oil occurs in the oil communication path between the first chamber 30a and second chamber 30b. Consequently, an open valve failure judgment cannot be formulated. Therefore, the CPU 71 proceeds to step 640 and waits until the elapsed time reaches the predetermined value t2. As the predetermined value t2, an appropriate value, which may render the second chamber oil temperature Too sufficiently higher than the initial oil temperature Too0, is set in accordance with the initial oil temperature Too0 and a predefined table stored in the ROM 72. Subsequently, steps 640 to 695 are performed, as is the case with (A) above, to judge whether a closed valve failure has occurred.
As described above, the use of the configuration according to the present embodiment, that is, the use of a simple configuration in which the oil temperature sensor 65a that is mounted on the side plate 31a2 of the oil pan cover 31 from the outside and secured is used, makes it possible to judge easily whether an open valve failure or closed valve failure has occurred in the thermostat valve apparatus 34.
<<Another Typical Failure Judgment Process>>
Another concrete example of the failure judgment process will now be described with reference to
As indicated in
The CPU 71 executes a “thermostat failure judgment process” routine 800, which is indicated in the flowchart in
First of all, the CPU 71 proceeds to step 805 and acquires the initial oil temperature Too0 and initial water temperature Tw0 that prevail immediately after engine startup in accordance with the outputs from the oil temperature sensor 65a and water temperature sensor 64.
Next, the CPU 71 proceeds to step 810 and judges whether the initial water temperature Tw0 is lower than a predetermined value Tw_ref.
If the initial water temperature Tw0 is not lower than the predetermined value Tw_ref (if the query in step 810 is answered “No”), the CPU 71 proceeds to step 895 and terminates the routine. When the engine is hot started (when, for instance, the engine is warmed up completely, operated for a long period of time, shut down, and then restarted immediately after shutdown), the second chamber oil temperature may be as high as the first chamber oil temperature prior to startup. In such a situation, it is basically impossible to properly formulate an open valve failure/closed valve failure judgment. In this instance, the CPU 71 does not check for a failure in the thermostat valve apparatus 34. As the predetermined value Tw_ref, a predetermined temperature (e.g., To_open+10° C. or so) that is sufficiently higher than the valve opening temperature To_open of the thermostat valve apparatus 34 is used.
If, on the other hand, the initial water temperature Tw0 is lower than the predetermined value Tw_ref (if the query in step 810 is answered “Yes”), the CPU 71 proceeds to step 815. In step 815, the CPU 71 resets the count reached by the timer t, and causes the timer t to start counting.
Next, the CPU 71 proceeds to step 820 and judges whether the initial water temperature Tw0 is lower than a predetermined temperature that is lower by a predetermined value ΔTs (e.g., approximately 10° C.) than the valve opening temperature To_open of the thermostat valve apparatus 34.
If the initial water temperature Tw0 is not lower than the predetermined temperature (if the query in step 820 is answered “No”), the first chamber oil temperature may reach the valve opening temperature To_open of the thermostat valve apparatus 34 immediately after startup and allow the second chamber oil temperature to rise. In such a situation, an open valve failure judgment is not properly formulated (an open valve failure may be erroneously located although the thermostat valve apparatus 34 properly operates). In this instance, the CPU 71 proceeds to step 825 and waits until the elapsed time from startup reaches a predetermined time t3 (e.g., 10 minutes or so). When the predetermined time t3 elapses, the CPU 71 performs a closed valve failure judgment process 900 (see
If, on the other hand, the initial water temperature Tw0 is lower than the predetermined temperature (if the query in step 820 is answered “Yes”), the CPU 71 proceeds to step 830 and waits until the cooling water temperature Tw reaches the valve opening temperature To_open of the thermostat valve apparatus 34. When the cooling water temperature Tw reaches the valve opening temperature To_open of the thermostat valve apparatus 34 (when the query in step 830 is answered “Yes”), the CPU 71 proceeds to step 835 and judges whether an average oil temperature rise rate ΔT/t=(Too−Too0)/t is not higher than a predetermined value C.
If the average oil temperature rise rate ΔT/t is higher than the predetermined value C (if the query in step 835 is answered “No”), the CPU 71 proceeds to step 840 and judges that an open valve failure has occurred. The CPU 71 then proceeds to step 845 and illuminates the warning lamp 83 to indicate the occurrence of the open valve failure. Next, the CPU proceeds to step 895 and terminates the routine.
If, on the other hand, the average oil temperature rise rate ΔT/t is not higher than the predetermined value C (if the query in step 835 is answered “Yes”), it is judged that no open valve failure has occurred in the thermostat valve apparatus 34. In this instance, the CPU 71 proceeds to step 850 and waits until the current cooling water temperature Tw reaches the predetermined temperature Tw_ref, which is sufficiently higher than the valve opening temperature To_open of the thermostat valve apparatus 34. When the cooling water temperature Tw reaches the predetermined temperature Tw_ref (when the query in step 850 is answered “Yes”), the CPU 71 proceeds to step 855, resets the timer again, and causes the timer to start counting.
Next, the CPU 71 proceeds to steps 860 and 865, and judges whether the current second chamber oil temperature Too is higher than the initial oil temperature Too0 by more than a predetermined value ΔT3 (whether the rise value ΔT=Too−Too0≧ΔT3) before a predetermined time t4 elapses after a timer reset (when the query in step 860 is answered “Yes”).
If the second chamber oil temperature rise value ΔT is not smaller than ΔT3 before the elapse of the predetermined time (t<t4) (if the queries in steps 860 and 865 are both answered “Yes”), the CPU 71 proceeds to step 870 and judges that no closed valve failure has occurred in the thermostat valve apparatus 34 (that is, the thermostat valve apparatus 34 is normal). Next, the CPU 71 proceeds to step 895 and terminates the routine.
If, on the other hand, the predetermined time t4 elapses after a timer reset while the second chamber oil temperature rise Δt is smaller than ΔT3 (if the query in step 860 is answered “No”), the CPU 71 performs the closed valve failure judgment process 900 (see
As described above, the use of the configuration according to the present embodiment, that is, the use of a simple configuration in which the water temperature sensor 64 and oil temperature sensor 65a that may be mounted from the outside of the engine 10 and secured is used, makes it possible to judge properly and easily whether an open valve failure or closed valve failure has occurred in the thermostat valve apparatus 34.
The oil pan apparatus 30′ according to the second embodiment has the same configuration as the oil pan apparatus 30 according to the first embodiment, and includes an oil temperature sensor 65b that is mounted on the side plate 32a2 of the oil pan separator 32 to acquire the temperature of the oil in the first chamber 30a. In the configuration according to the second embodiment, oil temperature sensors 65a and 65b are used to determine the actual behavior of the oil temperatures in the first and second chambers shown in
<<Typical Failure Judgment Process>>
A concrete example of a failure judgment process that is performed by the thermostat valve apparatus 34 according to the second embodiment will now be described with reference to a flowchart in
The CPU 71 executes a “thermostat failure judgment process” routine 1100, which is indicated in the flowchart in
First of all, the CPU 71 proceeds to step 1105 and acquires the first chamber initial oil temperature Toi0 and second chamber initial oil temperature Too0, which prevail immediately after engine startup, in accordance with the outputs from the oil temperature sensors 65a and 65b.
Next, the CPU 71 proceeds to step 1110 and resets the count reached by the timer t and let the timer t start counting.
Next, the CPU 71 proceeds to step 1115 and judges whether the first chamber initial oil temperature Toi0 is lower than a predetermined temperature that is lower by a predetermined value ΔT0 than the valve opening temperature To_open of the thermostat valve apparatus 34 (Too0<To_open−ΔT0).
(A) If the initial oil temperature Toi0 is lower than the predetermined temperature (if the query in step 1115 is answered “Yes”), the engine 10 is cold started and being warmed up. Therefore, the CPU 71 proceeds to step 1120 and waits until the current first chamber oil temperature Toi is lower than the valve opening temperature To_open of the thermostat valve apparatus 34 but sufficiently higher than during a cold startup sequence (until the first chamber oil temperature Toi is equal to To_open−ΔT4). As the value ΔT4, a relatively small value, such as 10° C. or so, may be used. When the first chamber oil temperature Toi is equal to To_open−ΔT4 (when the query in step 1120 is answered “Yes”), the CPU 71 proceeds to step 1125 and judges whether the difference between the first chamber oil temperature Toi and second chamber oil temperature Too is greater than a predetermined value ΔT5. As the predetermined value ΔT5, a relatively small value, such as 5° C. or so, may be used.
If the difference between the first chamber oil temperature Toi and second chamber oil temperature Too is not greater than the predetermined value ΔT5 (if the query in step 1125 is answered “No”), the CPU 71 proceeds to step 1130 and judges that the second chamber oil temperature Too is raised to a level close to the first chamber oil temperature Toi although the current first chamber oil temperature Toi is lower than the valve opening temperature To_open of the thermostat valve apparatus 34, that is, an open valve failure has occurred. The CPU 71 then proceeds to step 1135 and illuminates the warning lamp 83 to indicate the occurrence of the open valve failure. Finally, the CPU 71 proceeds to step 1195 and terminates the routine.
If, on the other hand, the difference between the first chamber oil temperature Toi and second chamber oil temperature Too is greater than the predetermined value ΔT5 (if the query in step 1125 is answered “Yes”), no open valve failure has occurred. Therefore, the CPU 71 proceeds to step 1140 and waits until the current first chamber oil temperature Toi is higher than the valve opening temperature To_open of the thermostat valve apparatus 34 by a value ΔT6. As the value ΔT6, a temperature of 10° C. or so may be used. More specifically, the value ΔT6 should make it possible to expect that the second chamber oil temperature Too will be considerably higher than the initial temperature Too0 if, as indicated in
When the first chamber oil temperature Toi is higher than the valve opening temperature To_open of the thermostat valve apparatus 34 by ΔT6 (when the query in step 1140 is answered “Yes”), the CPU 71 proceeds to step 1145 and acquires the second chamber oil temperature rise ΔT=Too−Too0 since engine startup, as is the case with step 645 in the aforementioned routine 600. Next, the CPU 72 proceeds to step 1150, which is similar to step 650 in the aforementioned routine 600, and judges whether the temperature rise ΔT is smaller than the predetermined value ΔT2.
If the temperature rise ΔT is not smaller than the predetermined value ΔT2 (if the query in step 1150 is answered “Yes”), the CPU 71 proceeds to step 1155 and judges that no closed valve failure has occurred in the thermostat valve apparatus 34. Next, the CPU 71 proceeds to step 1195 and terminates the routine.
If, on the other hand, the temperature rise ΔT is smaller than the predetermined value ΔT2 (if the query in step 1150 is answered “No”), the CPU 71 proceeds to step 1160 and judges that a closed valve failure has occurred. The CPU 71 then proceeds to step 1165 and illuminates the warning lamp 83 to indicate the occurrence of the closed valve failure. Finally, the CPU 71 proceeds to step 1195 and terminates the routine.
(B) If the initial oil temperature Toi0 is not lower than the predetermined temperature (if the query in step 1115 is answered “No”), the current engine startup operation is a hot start, which does not require any warm-up operation. Therefore, the thermostat valve apparatus 34 opens immediately after engine startup so that the interchange of oil may occur in the oil communication path between the first chamber 30a and second chamber 30b. Consequently, an open valve failure judgment cannot be formulated. Therefore, the CPU 71 proceeds to step 1140 and performs steps 1140 to 1165 to check for a closed valve failure. Finally, the CPU 71 proceeds to step 1195 and terminates the routine.
The foregoing embodiments and concrete examples are considered to be the best by the applicant at the time of application of the present invention, as mentioned earlier. They are to be considered in all respects only as illustrative and not restrictive. The present invention is not limited to the foregoing embodiments, but extends to various modifications that does not change the essential part of the present invention. Although some modified embodiments are described below, they are also to be considered only as illustrative and not restrictive.
The configuration of the oil pan apparatus according to the present invention can be applied not only to the aforementioned engine but also to an automatic transmission and various other apparatuses that are equipped with a lubrication device based on the oil pan apparatus.
Further, in addition to the thermostat valve apparatus 34, which has been described in conjunction with the foregoing concrete examples, a solenoid valve apparatus, a hydraulically-operated valve apparatus, a pneumatic valve apparatus, or other similar apparatuses may be used as the valve mechanism to be applied to the present invention. Valve open/close control may be exercised in accordance with the operating time or a cooling water temperature instead of the (first chamber) oil temperature, which is used in the foregoing concrete examples. As the valve mechanism to be applied to the present invention, it is possible to use a so-called open/close valve (which opens/closes upon power on/off) in addition to a flow control valve whose opening is variable.
The structure for fastening the oil pan separator and oil pan cover to the cylinder block is not limited to the use of the aforementioned bolts for simultaneous fastening. Various other fastening structures (e.g., a chuck-based fastening structure) may be used alternatively.
In the foregoing embodiments, the oil pan cover, which is substantially shaped like a bathtub, and the oil pan separator are stacked so that the second chamber is formed beneath the first chamber. However, the present invention is not limited to the use of such a configuration. For example, the oil pan separator may alternatively comprise a partition wall that extends vertically to divide the internal space of the oil pan cover in a horizontal direction.
Another alternative is to check, before the occurrence of a failure, for abnormalities, such as a degraded operation characteristic of the thermostat valve apparatus 34 (e.g., delayed follow-up of the valve opening ratio in relation to temperature changes). In other words, an abnormality may be located to issue a warning before an actual failure occurs.
Further, if the judgment result obtained in step 615 of the flowchart shown in
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2005-009822 | Jan 2005 | JP | national |
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PCT/JP2006/300905 | 1/16/2006 | WO | 00 | 6/8/2007 |
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WO2006/077996 | 7/27/2006 | WO | A |
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