JP5482674B2 - Oil consumption reduction control device - Google Patents

Description

  The present invention relates to an oil consumption reduction control device.

  A technique is disclosed in which the control valve is controlled by managing the cooling water temperature on both the inlet side and the outlet side of the internal combustion engine in the cooling water passage (see, for example, Patent Document 1). According to this, since the control temperature of the cooling water is set based on the engine load, the ideal cooling state of the internal combustion engine can be properly maintained for each operation region, and the operation performance, fuel consumption, etc. of the internal combustion engine can be maintained. improves.

JP 05-332136 A Japanese Patent Application Laid-Open No. 62-237023 JP-A-07-091251 JP 2001-152851 A

  By the way, in recent years, with a demand for lowering the friction of an internal combustion engine, lowering of piston ring tension and lowering of oil viscosity have been promoted. However, when the viscosity of the oil is reduced, the oil consumption increases as a contradiction. Therefore, it is desired to reduce the oil consumption while reducing the friction of the internal combustion engine. Here, the viscosity of the oil changes according to the temperature, and when the temperature decreases, the viscosity of the oil increases. Therefore, in order to reduce the oil consumption while reducing the friction of the internal combustion engine, the temperature of the cooling water of the internal combustion engine is controlled by applying the technique of the above-mentioned Patent Document 1, and the temperature of the oil in the internal combustion engine is reduced. Control is also conceivable. However, in the technique of Patent Document 1 described above, the temperature of the cooling water is controlled based on the engine load. Therefore, even if the amount of oil consumption is actually low, the temperature of the cooling water is lowered to reduce the oil temperature. In some cases, the viscosity of the oil was increased and the evaporability of the oil was decreased. When the amount of oil consumption is originally low, the fuel consumption deterioration due to the temperature drop of the cooling water becomes a big problem.

  An object of the present invention is to provide a technique for reducing oil consumption while minimizing deterioration in fuel consumption due to a decrease in cooling water temperature by optimally controlling the temperature of cooling water.

In the present invention, the following configuration is adopted. That is, the present invention
An adjustment mechanism for adjusting the temperature of the cooling water circulating in the internal combustion engine;
Oil consumption calculation means for calculating the consumption of oil used in the internal combustion engine;
When the oil consumption calculated by the oil consumption calculation means is greater than or equal to a predetermined amount, control means for reducing the temperature of the cooling water using the adjustment mechanism;
An oil consumption reduction control device comprising:

  Here, if the consumption amount of the predetermined amount of oil is more than that, it is an amount that requires a decrease in the temperature of the cooling water in order to increase the viscosity of the oil and decrease the evaporation property. That is, the predetermined amount is a threshold value as to whether or not the temperature of the cooling water needs to be decreased in order to increase the viscosity of the oil and decrease the evaporation property.

  According to the present invention, the temperature of the cooling water is decreased using the adjusting mechanism based on the oil consumption only when the temperature of the cooling water is required to increase the viscosity of the oil and decrease the evaporability. , Oil consumption can be reduced. Thereby, when the oil consumption is originally small, the temperature of the cooling water is not lowered, and the deterioration of the fuel consumption due to the temperature drop of the cooling water can be avoided. Therefore, by controlling the temperature of the cooling water optimally based on the oil consumption, the oil consumption can be reduced while minimizing the deterioration in fuel consumption caused by the temperature drop of the cooling water.

In the present invention, the following configuration is adopted. That is, the present invention
An adjustment mechanism for adjusting the temperature of the cooling water circulating in the internal combustion engine;
Oil viscosity detecting means for detecting the viscosity of oil used in the internal combustion engine;
When the viscosity of the oil detected by the oil viscosity detection means is equal to or lower than a predetermined viscosity, control means for lowering the temperature of the cooling water using the adjustment mechanism;
An oil consumption reduction control device comprising:

  Here, the viscosity of the oil having a predetermined viscosity is a viscosity that requires a temperature drop of the cooling water in order to increase the viscosity of the oil and decrease the evaporability when it is less than that. That is, the predetermined viscosity is a threshold value as to whether or not the temperature of the cooling water needs to be lowered in order to increase the viscosity of the oil and decrease the evaporability.

  According to the present invention, the temperature of the cooling water is lowered using the adjusting mechanism based on the viscosity of the oil only when the temperature of the cooling water needs to be lowered in order to increase the viscosity of the oil and reduce the evaporation property. Oil consumption can be reduced. Thereby, when the oil consumption is originally small, the temperature of the cooling water is not lowered, and the deterioration of the fuel consumption due to the temperature drop of the cooling water can be avoided. Therefore, by controlling the temperature of the cooling water optimally based on the viscosity of the oil, it is possible to reduce the amount of oil consumed while minimizing the deterioration in fuel consumption caused by the temperature drop of the cooling water.

  According to the present invention, by controlling the temperature of the cooling water optimally, it is possible to reduce the amount of oil consumed while minimizing the deterioration of fuel consumption caused by the temperature reduction of the cooling water.

1 is a diagram illustrating a schematic configuration of an internal combustion engine according to Embodiment 1 of the present invention. It is a figure which shows the relationship between the viscosity of the oil which concerns on Example 1, and the consumption of oil. 3 is a flowchart illustrating an oil consumption reduction control routine 1 according to the first embodiment. FIG. 3 is a diagram illustrating a schematic configuration of an internal combustion engine according to a second embodiment. 7 is a flowchart illustrating an oil consumption reduction control routine 2 according to a second embodiment.

  Specific examples of the present invention will be described below.

<Example 1>
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine to which an oil consumption reduction control device according to Embodiment 1 of the present invention is applied. In the internal combustion engine 1 shown in FIG. 1, oil stored in an oil pan is supplied to components that require lubrication, such as a cylinder block and a cylinder head. In the oil pan, an oil level sensor 2 for detecting the height of the oil level to be stored is disposed.

  Further, the internal combustion engine 1 is provided with a cooling water passage 4 for cooling water circulating through the radiator 3 in the water jacket. In the cooling water passage 4, the cooling water of the internal combustion engine 1 flows into the radiator 3 through the radiator passage 5, thereby lowering the temperature of the cooling water and lowering the temperature of the internal combustion engine 1. The cooling water passage 4 is provided with a bypass passage 6 that bypasses the radiator 3. The bypass passage 6 prevents the cooling water temperature from being lowered by bypassing the radiator 3. In addition, a heater 7 is provided in the bypass passage 6, and the temperature of the cooling water can be warmed by the heater 7 to warm up the internal combustion engine 1. A control valve 8 for switching the passage through which the cooling water flows between the radiator passage 5 and the bypass passage 6 is disposed at the connection portion between the radiator passage 5 and the bypass passage 6. By opening the control valve 8, the cooling water can be circulated through the radiator passage 5, and the temperature of the internal combustion engine 1 can be lowered by lowering the temperature of the cooling water. On the other hand, by closing the control valve 8, the cooling water can be circulated through the bypass passage 6, and the temperature of the cooling water can be maintained or raised. The control valve 8 is controlled to open and close by the temperature of the cooling water detected by the water temperature sensor 9 disposed in the cooling water passage 4. That is, if the temperature of the cooling water detected by the water temperature sensor 9 is high, the control valve 8 is opened, and the cooling water is passed through the radiator passage 5 to cool the internal combustion engine 1. On the other hand, if the temperature of the cooling water detected by the water temperature sensor 9 is low, the control valve 8 is closed and the cooling water is circulated through the bypass passage 6 so that the internal combustion engine 1 is not cooled. Such a configuration including the radiator 3, the cooling water passage 4, the heater 7, the control valve 8, the water temperature sensor 9 and the like corresponds to the adjusting mechanism of the present invention.

  The internal combustion engine 1 is provided with an ECU (electronic control unit) 10. Various sensors such as the oil level sensor 2 and the water temperature sensor 9 are connected to the ECU 10 via electric wiring, and output signals of these various sensors are input to the ECU 10. On the other hand, a heater 7 and a control valve 8 are connected to the ECU 10 via electric wiring, and these devices are controlled by the ECU 10.

(Oil consumption reduction control)
By the way, in recent years, with a demand for lower friction of the internal combustion engine 1, lowering of the piston ring tension and lowering of the viscosity of the oil have been promoted. However, when the viscosity of the oil is reduced, the oil consumption increases as a contradiction. FIG. 2 is a diagram showing the relationship between oil viscosity and oil consumption. As shown in FIG. 2, when the viscosity of the oil decreases, the oil evaporability increases and the oil consumption increases. Therefore, it is desired to reduce oil consumption while lowering the friction of the internal combustion engine 1.

  Here, the viscosity of the oil changes according to the temperature, and when the temperature decreases, the viscosity of the oil increases. Therefore, in order to reduce the oil consumption while reducing the friction of the internal combustion engine 1, it has been considered to control the temperature of the cooling water in the internal combustion engine 1 and the temperature of the oil in the internal combustion engine 1. For this reason, conventionally, it has been considered to control the temperature of the cooling water based on the engine load.

  In practice, however, even when the amount of oil consumption is low, the temperature of the cooling water is lowered, the viscosity of the oil is increased, and the evaporability of the oil is lowered. When the amount of oil consumption is originally low, the fuel consumption deterioration due to the temperature drop of the cooling water becomes a big problem.

  Therefore, in this embodiment, when the amount of oil consumed is equal to or greater than a predetermined amount that is a threshold value indicating whether or not the temperature of the cooling water needs to be decreased in order to increase the viscosity of the oil and decrease the evaporation property, The temperature was lowered.

Here, if the consumption amount of the predetermined amount of oil is more than that, it is an amount that requires a decrease in the temperature of the cooling water in order to increase the viscosity of the oil and decrease the evaporation property.

  Specifically, first, the oil level sensor 2 detects the oil level height before starting the internal combustion engine 1. Further, the ECU 10 stores the oil level before the previous engine start. As a result, the amount of oil per unit distance is determined based on the amount of oil used determined from the change in oil level between the previous engine start and the current engine start, and the previous travel distance of the internal combustion engine 1. The consumption (hereinafter referred to as oil consumption) is calculated. The amount of oil consumed can be calculated by dividing the amount of oil used by the distance traveled. The ECU 10 that calculates the oil consumption corresponds to the oil consumption calculation means of the present invention.

  When the calculated oil consumption is equal to or greater than a predetermined amount, the set valve opening temperature at which the control valve 8 is opened is lowered as compared with the case where the oil consumption is less than the predetermined amount. I made it. That is, the set valve opening temperature A ° C. for opening the control valve 8 when the oil consumption is equal to or higher than the predetermined amount and the set valve opening temperature B ° C. when the oil consumption is lower than the predetermined amount are A <B is set to have a relationship.

  As a result, when the oil consumption is greater than or equal to the predetermined amount, the control valve 8 is activated when the coolant temperature is A (<B) ° C., which is lower than when the oil consumption is less than the predetermined amount. Open the valve. Then, the cooling water flows through the radiator passage 5, the cooling water is cooled by the radiator 3, and the cooled cooling water flows into the internal combustion engine 1, whereby the temperature of the internal combustion engine 1 and hence the oil can be lowered. Therefore, when the temperature of the oil is lowered, the viscosity of the oil is increased and the evaporability is lowered, so that the oil consumption can be reduced.

  On the other hand, when the oil consumption is less than the predetermined amount, the control valve 8 is opened when the coolant temperature is B (> A) ° C., which is higher than when the oil consumption is the predetermined amount or more. I speak. For this reason, the cooling water does not flow through the radiator passage 5 and is cooled unless the temperature of the cooling water becomes high to some extent. Therefore, when the amount of oil consumption is originally low, the temperature of the cooling water is not lowered, and the amount of oil consumption is not reduced, so that the fuel consumption deterioration due to the temperature reduction of the cooling water can be avoided. .

  As described above, in this embodiment, the control valve 8 can be easily opened based on the oil consumption only when the temperature of the cooling water needs to be decreased in order to increase the viscosity of the oil and decrease the evaporation property. Thus, the temperature of the cooling water can be lowered and the oil consumption can be reduced. Thereby, when the oil consumption is originally small, the control valve 8 is not easily opened, the temperature of the cooling water is not decreased, and the deterioration of the fuel consumption due to the temperature decrease of the cooling water can be avoided. it can. Therefore, by controlling the temperature of the cooling water optimally based on the oil consumption, the oil consumption can be reduced while minimizing the deterioration in fuel consumption caused by the temperature drop of the cooling water.

(Oil consumption reduction control routine 1)
The oil consumption reduction control routine 1 in the ECU 10 will be described based on the flowchart shown in FIG. FIG. 3 is a flowchart showing the oil consumption reduction control routine 1. This routine is executed by the ECU 10. The ECU 10 that executes this routine corresponds to the control means of the present invention.

  The routine shown in FIG. 3 is started when the ignition SW is turned on. When this routine is started, oil consumption is calculated in S101. That is, the amount of oil used from the change in the oil level before the previous engine start stored in the ECU 10 and the oil level before the current engine start detected by the current oil level sensor 2. Ask for. Then, the oil consumption amount per unit distance is calculated by dividing the obtained oil usage amount by the previous travel distance of the internal combustion engine 1 stored in the ECU 10.

  In S102, it is determined whether or not the oil consumption calculated in S101 is a predetermined amount or more. If an affirmative determination is made in S102, the process proceeds to S103. On the other hand, if a negative determination is made in S102, the process proceeds to S104.

  In S103, since the amount of oil consumption is equal to or greater than the predetermined amount, the set valve opening temperature for opening the control valve 8 is lowered A (as compared to the case where the amount of oil consumption is less than the predetermined amount A ( <B) Set to ° C. After the processing of this step, this routine is once ended.

  In S104, since the oil consumption is less than the predetermined amount, the set valve opening temperature at which the control valve 8 is opened is increased as compared with the case where the oil consumption is the predetermined amount or more B ( > A) Set to ° C. After the processing of this step, this routine is once ended.

  In this routine, the control valve 8 is easily opened when the oil consumption is a predetermined amount or more, and the control valve 8 is easily opened when the oil consumption is small. Not. Thus, by controlling the temperature of the cooling water optimally based on the oil consumption, it is possible to reduce the oil consumption while minimizing the deterioration in fuel consumption caused by the temperature reduction of the cooling water.

<Example 2>
FIG. 4 is a diagram illustrating a schematic configuration of an internal combustion engine to which the oil consumption reduction control device according to the second embodiment of the present invention is applied. In the internal combustion engine 1 shown in FIG. 4, an oil viscosity sensor 11 that detects the viscosity of stored oil is disposed in the oil pan. The oil viscosity sensor 11 corresponds to the oil viscosity detecting means of the present invention. Since other configurations are the same as those in the above embodiment, the description thereof is omitted.

(Oil consumption reduction control)
In this embodiment, when the viscosity of the oil is equal to or lower than a predetermined viscosity that is a threshold value indicating whether or not the temperature of the cooling water needs to be lowered in order to increase the viscosity of the oil and reduce the evaporation property, Reduced.

  Here, the viscosity of the oil having a predetermined viscosity is a viscosity that requires a temperature drop of the cooling water in order to increase the viscosity of the oil and decrease the evaporability when it is less than that.

  Specifically, first, the oil viscosity sensor 11 detects the viscosity of the oil at every predetermined timing.

  When the detected oil viscosity is equal to or lower than the predetermined viscosity, the set valve opening temperature for opening the control valve 8 is decreased every time the oil viscosity is detected. That is, the set valve opening temperature for opening the control valve 8 when the oil viscosity is equal to or lower than the predetermined viscosity is decreased by T ° C. every time the oil viscosity is detected, and the set valve opening temperature when the oil viscosity is higher than the predetermined viscosity. The temperature was increased by T ° C. every time the oil viscosity was detected. An upper limit temperature is set for the set valve opening temperature.

  Thereby, when the viscosity of the oil is equal to or lower than the predetermined viscosity, the control valve 8 is opened when the temperature of the cooling water is lower than when the viscosity of the oil is higher than the predetermined viscosity. Then, the cooling water flows through the radiator passage 5, the cooling water is cooled by the radiator 3, and the cooled cooling water flows into the internal combustion engine 1, whereby the temperature of the internal combustion engine 1 and hence the oil can be lowered. Therefore, when the temperature of the oil is lowered, the viscosity of the oil is increased and the evaporability is lowered, so that the oil consumption can be reduced.

  On the other hand, when the viscosity of the oil is higher than the predetermined viscosity, the control valve 8 is opened when the temperature of the cooling water is higher than that when the viscosity of the oil is equal to or lower than the predetermined viscosity. For this reason, the cooling water does not flow through the radiator passage 5 and is cooled unless the temperature of the cooling water becomes high to some extent. Therefore, when the amount of oil consumption is originally low, the temperature of the cooling water is not lowered, and the amount of oil consumption is not reduced, so that the fuel consumption deterioration due to the temperature reduction of the cooling water can be avoided. .

  As described above, in this embodiment, the control valve 8 is made easy to open based on the viscosity of the oil only when the temperature of the cooling water needs to be decreased in order to increase the viscosity of the oil and decrease the evaporation property. The temperature of the cooling water can be lowered, and the amount of oil consumption can be reduced. Thereby, when the oil consumption is originally small, the control valve 8 is not easily opened, the temperature of the cooling water is not decreased, and the deterioration of the fuel consumption due to the temperature decrease of the cooling water can be avoided. it can. Therefore, by controlling the temperature of the cooling water optimally based on the viscosity of the oil, it is possible to reduce the amount of oil consumed while minimizing the deterioration in fuel consumption caused by the temperature drop of the cooling water.

(Oil consumption reduction control routine 2)
The oil consumption reduction control routine 2 in the ECU 10 will be described based on the flowchart shown in FIG. FIG. 5 is a flowchart showing the oil consumption reduction control routine 2. This routine is executed by the ECU 10. The ECU 10 that executes this routine corresponds to the control means of the present invention.

  The routine shown in FIG. 5 is started when the ignition SW is turned on. When this routine is started, the oil viscosity is detected by the oil viscosity sensor 11 in S201.

  In S202, it is determined whether or not the viscosity of the oil detected in S201 is equal to or lower than a predetermined viscosity. If an affirmative determination is made in S202, the process proceeds to S203. On the other hand, if a negative determination is made in S202, the process proceeds to S204.

  In S203, since the oil viscosity is equal to or lower than the predetermined viscosity, the set valve opening temperature for opening the control valve 8 is decreased by T ° C.

  In S204, since the oil viscosity is higher than the predetermined viscosity, the set valve opening temperature for opening the control valve 8 is increased by T ° C. An upper limit temperature is set for the set valve opening temperature.

  In S205, it is determined whether or not the internal combustion engine is operating. If a positive determination is made in S205, the process proceeds to S201. On the other hand, if a negative determination is made in S205, the routine is temporarily terminated after the processing of this step.

  In this routine, the control valve 8 is easily opened when the oil viscosity is equal to or lower than the predetermined viscosity, and the control valve 8 is not easily opened when the oil viscosity is high. . Thus, by controlling the temperature of the cooling water optimally based on the viscosity of the oil, it is possible to reduce the amount of oil consumed while minimizing the deterioration of fuel consumption caused by the temperature drop of the cooling water.

In particular, in Example 1, the set valve opening temperature can be changed only in a long span until one travel is completed, and the valve opening temperature has only two stages. However, according to the present embodiment, the set valve opening temperature can be changed in a short span during traveling, and the set valve opening temperature can be changed in multiple stages. Therefore, in this embodiment, when the oil is changed and the viscosity of the oil is changed, or when the oil deteriorates and the viscosity is lowered, the oil consumption reduction control is performed by changing the set valve opening temperature immediately. be able to.

<Others>
The oil consumption reduction control device according to the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the present invention.

1 Internal combustion engine 2 Oil level sensor 3 Radiator 4 Cooling water passage 5 Radiator passage 6 Bypass passage 7 Heater 8 Control valve 9 Water temperature sensor 10 ECU
11 Oil viscosity sensor

Claims (4)

An adjustment mechanism for adjusting the temperature of the cooling water circulating in the internal combustion engine;
Oil consumption calculation means for calculating the consumption of oil used in the internal combustion engine;
When the oil consumption calculated by the oil consumption calculation means is greater than or equal to a predetermined amount, control means for reducing the temperature of the cooling water using the adjustment mechanism;
An oil consumption reduction control device comprising:   2. The oil consumption reduction control device according to claim 1, wherein the predetermined amount is a threshold value indicating whether or not the temperature of the cooling water needs to be decreased in order to increase the viscosity of the oil and decrease the evaporability. An adjustment mechanism for adjusting the temperature of the cooling water circulating in the internal combustion engine;
Oil viscosity detecting means for detecting the viscosity of oil used in the internal combustion engine;
When the viscosity of the oil detected by the oil viscosity detection means is equal to or lower than a predetermined viscosity, control means for lowering the temperature of the cooling water using the adjustment mechanism;
An oil consumption reduction control device comprising:   4. The oil consumption reduction control device according to claim 3, wherein the predetermined viscosity is a threshold value indicating whether or not the temperature of the cooling water needs to be decreased in order to increase the viscosity of the oil and decrease the evaporation property.

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