JP2016098663A - On-vehicle internal combustion engine additive residual amount calculation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle internal combustion engine additive residual amount calculation apparatus capable of calculating a residual amount of an additive using a detection value of a level sensor appropriately even if the residual amount of the additive reserved in a tank changes.SOLUTION: An on-vehicle internal combustion engine additive residual amount calculation apparatus includes a calculation part for: setting (S310), in accordance with a level sensor value L, an execution range being a range of acceleration with which to execute calculation processing (S340) for a residual amount by referring to the same level sensor value L detected by a level sensor; and executing, if acceleration detected by an acceleration sensor is within an execution range (S320 and Yes for S330), calculation processing for a residual amount to refer to the same level sensor value L (S340).SELECTED DRAWING: Figure 6

Description

  This invention relates to the addition of an on-vehicle internal combustion engine that calculates the remaining amount of additive added to the exhaust flowing through the exhaust passage in order to purify the exhaust of the on-vehicle internal combustion engine, that is, the remaining amount of additive stored in the tank. The present invention relates to an agent remaining amount calculation device.

  2. Description of the Related Art An exhaust gas purification device that adds an additive to exhaust gas flowing through an exhaust passage in order to purify exhaust gas from an in-vehicle internal combustion engine is known. A vehicle equipped with such an exhaust purification device is provided with a tank for storing a liquid additive, and the additive stored in the tank is added to the exhaust flowing through the exhaust passage. Here, in the exhaust emission control device described in Patent Document 1, the remaining amount of the additive is calculated by detecting the liquid level, which is the height of the liquid level of the additive stored in the tank, by the level sensor. doing.

  In addition, when the vehicle is traveling on a slope or during acceleration / deceleration, the additive is biased in the tank, and the liquid level detected by the level sensor is not a value commensurate with the actual remaining amount of additive. End up. On the other hand, Patent Document 1 discloses a configuration in which a liquid level is detected by a level sensor only when the vehicle is in an operation state in which the vehicle inclination angle with respect to a horizontal plane is smaller than an allowable angle. Patent Document 1 also discloses a configuration in which the liquid level is detected only when the acceleration and deceleration of the vehicle are equal to or less than allowable values.

JP 2008-291828 A

  By the way, when the remaining amount of the additive stored in the tank is small, when the additive is biased to one side in the tank due to the inclination of the vehicle, there is almost no additive at the position where it touches the level sensor. It is easy to become. Therefore, the detected value of the liquid level may become a value indicating that the height of the liquid level is the lowest even though the additive remains in the tank. On the other hand, when a lot of additives are stored in the tank and the tank is almost filled with additives, even if the vehicle tilts in the same way, add it to the position where it touches the level sensor. The agent does not disappear, and the detection value of the liquid level does not become a value indicating that the height of the liquid level is the lowest.

  In the additive remaining amount calculation device that calculates the remaining amount of the additive using the detection value of the level sensor, it is necessary to consider the influence of the inclination of the vehicle on the detection value of the level sensor as disclosed in Patent Document 1. There is. However, the magnitude of the influence of the vehicle inclination on the detection value of the level sensor varies depending on the remaining amount of the additive stored in the tank as described above.

  The present invention has been made in view of such circumstances, and the purpose of the present invention is to appropriately use the detection value of the level sensor even if the remaining amount of the additive stored in the tank changes. An object of the present invention is to provide an additive remaining amount calculating device for an in-vehicle internal combustion engine capable of calculating the remaining amount.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
An onboard internal combustion engine additive remaining amount calculation device for solving the above-mentioned problems is provided in a tank storing liquid additive and detects a liquid level indicating the height of the additive liquid level. A level sensor, an acceleration sensor, and a calculation unit that executes a calculation process for calculating the remaining amount of the additive with reference to the liquid level detected by the level sensor. In this additive remaining amount calculation device for an in-vehicle internal combustion engine, the calculation unit sets an execution range, which is an acceleration range for executing the calculation process, according to the liquid level detected by the level sensor.

  When the vehicle tilts, the tilt of the acceleration sensor with respect to the vertical direction also changes. For this reason, the direction of gravity acting on the acceleration sensor changes according to the inclination of the vehicle, and the acceleration detected by the acceleration sensor changes according to the inclination of the vehicle. Therefore, the inclination of the vehicle, that is, the inclination of the tank storing the additive can be grasped by referring to the magnitude of the acceleration detected by the acceleration sensor.

  In the above configuration using such a relationship, an execution range using acceleration as an index is set, and when the acceleration detected by the acceleration sensor is within the execution range, the liquid level detected by the level sensor is referred to. A calculation process for calculating the remaining amount of the additive is executed. As a result, the bias of the additive in the tank has a large effect on the detection value of the level sensor, and the liquid level is referenced in a situation where the remaining amount of additive cannot be calculated appropriately based on the detected liquid level. It can suppress that the calculation process to perform is performed.

  In order to calculate the remaining amount with high accuracy, a calculation process that refers to the liquid level is performed only when the difference between the remaining amount calculated from the liquid level and the actual remaining amount is very small. If a narrow execution range is set, the calculation process becomes difficult to execute. On the other hand, if a wide execution range is set in order to secure an execution opportunity for the calculation process, the liquid level is referenced even when the difference between the remaining amount calculated from the liquid level and the actual remaining amount is large. As a result, the calculation accuracy of the remaining amount is lowered. Therefore, when setting the execution range, it is necessary to set an execution range having an appropriate width in accordance with the degree of influence of the vehicle inclination on the liquid level that is the detection value of the level sensor.

  However, the influence of the inclination of the vehicle on the liquid level, which is the detection value of the level sensor, changes according to the remaining amount. For this reason, even if the optimized execution range is set so that it becomes the optimum size when the remaining amount is the predetermined amount, if the remaining amount changes after the additive is consumed, the range of the execution range is not appropriate. End up.

  On the other hand, according to the above configuration, the execution range is set according to the liquid level detected by the level sensor. For this reason, even if the additive is consumed and the remaining amount of the additive changes, the execution range taking into account the change in the remaining amount is set each time. Therefore, according to the above configuration, it is possible to suppress the execution range from becoming inappropriate due to a change in the remaining amount of the additive. That is, according to the above configuration, even when the remaining amount of the additive stored in the tank changes, the remaining amount of the additive can be calculated suitably using the detection value of the level sensor. .

  Further, in one aspect of the additive remaining amount calculation device for an in-vehicle internal combustion engine, when the liquid level detected by the level sensor is equal to or higher than a first level threshold, the calculation unit determines that the liquid level is the first level. The execution range is set wider than when the second level threshold is smaller than the first level threshold.

  If the remaining amount of additive is low, when the additive is biased to one side of the tank due to the inclination of the vehicle, there will be almost no additive at the position touching the level sensor, and the additive will remain in the tank. Nevertheless, there is a possibility that the detected value of the liquid level becomes a value indicating that the height of the liquid level is the lowest. On the other hand, when a lot of additives are stored in the tank and the tank is almost filled with additives, even if the vehicle tilts in the same way, add it to the position where it touches the level sensor. The agent will not disappear.

  On the other hand, according to the above configuration, the execution range is made wider when the level is equal to or higher than the first level threshold than when the level is lower than the second level threshold. Therefore, based on the fact that the liquid level is equal to or higher than the first level threshold value, when it is considered that the remaining amount of the additive is larger than when the liquid level is less than the second level threshold value, the liquid level is It is possible to increase the execution chance of the remaining amount calculation process that refers to the liquid level compared to when the level is less than the second level threshold.

  Therefore, according to the above configuration, the remaining amount of the additive stored in the tank is small, and the detected value of the liquid level is the highest when the liquid level is the highest even though the additive remains in the tank. It is possible to prevent the remaining amount from being calculated with reference to the detected value when there is a possibility that the value will be low. On the other hand, even if the amount of the additive stored in the tank is large and the vehicle is tilted, the level of the additive is considered to be present at the position where it touches the level sensor. An opportunity to calculate the remaining amount with reference to the level can be secured.

  Moreover, in this additive remaining amount calculation apparatus for an in-vehicle internal combustion engine, a configuration including a storage unit that stores the remaining amount calculated by the calculation unit may be employed. When such a configuration is adopted, the calculation unit calculates an addition amount integrated value obtained by integrating the addition amount of the additive from the calculation of the remaining amount of the additive to the next calculation of the remaining amount. At the same time, when the acceleration detected by the acceleration sensor is out of the execution range, the remaining amount is calculated by subtracting the added amount integrated value from the previously calculated remaining amount stored in the storage unit.

  According to the above configuration, even when the acceleration detected by the acceleration sensor is outside the execution range, that is, when the remaining amount calculation process referring to the liquid level detected by the level sensor is not executed, The remaining amount can be calculated by subtracting the added amount integrated value from the additive remaining amount.

  Further, in one aspect of the additive remaining amount calculation device for an in-vehicle internal combustion engine, the calculation unit has a constant divergence between the remaining amount calculated through the calculation process and the actual additive remaining amount as the execution range. Set the acceleration range that falls within the range.

  According to the above configuration, when the difference between the remaining amount calculated through the calculation process referring to the liquid level and the actual remaining amount of the additive falls within a certain range, that is, the calculated remaining amount error is constant. When the value falls within the range, the calculation process referring to the liquid level is performed. For this reason, it is possible to prevent the remaining amount including a large error exceeding a certain range from being calculated through the calculation process that refers to the liquid level. In other words, an error in the remaining amount calculated through the calculation process that refers to the liquid level can be suppressed within a certain range.

  Further, in one aspect of the additive remaining amount calculation device for an in-vehicle internal combustion engine, the calculation unit includes, as the execution range, a first execution range for acceleration in the vehicle longitudinal direction and a second execution range for acceleration in the vehicle lateral direction. Set the execution range. In the calculation unit, the vehicle longitudinal acceleration detected by the acceleration sensor is within the first execution range, and the vehicle lateral acceleration detected by the acceleration sensor is the second execution range. If it is within the range, the calculation process is executed.

  According to the above configuration, the acceleration sensor can detect the pitching and rolling of the vehicle. Therefore, as compared with the case where whether or not to execute the remaining amount calculation process that refers to the detected liquid level is determined based on the acceleration in one direction, the inclination of the vehicle is given to the liquid level detected by the level sensor. The remaining amount of the additive can be calculated in consideration of the influence more accurately.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the structure of an internal combustion engine provided with the exhaust gas purification device with which this apparatus is applied, and this exhaust gas purification device about one Embodiment of the additive residual amount calculation apparatus of a vehicle-mounted internal combustion engine. It is the schematic which showed the state (solid line) and the state (dashed line) which the liquid level of the urea water in a tank is not inclined, (a) shows the state with little residual amount of urea water, (b ) Shows a state where the tank is almost filled with urea water. It is a schematic diagram which shows the shape of a tank, (a) shows typically the shape of the tank seen from upper direction, (b) shows typically the shape of the tank seen from the left side, (c) is front The shape of the tank seen from is schematically shown. It is the graph which showed the relationship between the actual residual amount of the stored urea water, and the liquid level detected by the level sensor for each inclination angle of the vehicle, (a) (B) shows the relationship at the time of rearward rising inclination. It is the graph which showed the relationship between the actual residual amount of the urea water stored for every inclination-angle of a vehicle, and the liquid level detected by a level sensor, (a) is the said relationship at the time of a left-up inclination. (B) shows the relationship at the time of the upward slope. The flowchart which shows a series of process procedures for the control apparatus concerning the embodiment to calculate the residual amount of urea water, and to perform alerting | reporting process. FIG. 4 is an arithmetic map for calculating an acceleration determination value, (a) is an arithmetic map for calculating an acceleration determination value B, and (b) is an arithmetic map for calculating an acceleration determination value C. FIG. An arithmetic map for calculating an acceleration determination value is shown. (A) is an arithmetic map for calculating an acceleration determination value X, and (b) is an arithmetic map for calculating an acceleration determination value Y. An arithmetic map for determining acceleration determination values B, C, Y, and X in the modified example.

  Hereinafter, an embodiment in which an additive remaining amount calculating device for an in-vehicle internal combustion engine is embodied in a vehicle equipped with an internal combustion engine equipped with a purification device that purifies exhaust gas by adding an additive to the exhaust flowing through the exhaust passage, A description will be given with reference to FIGS. The internal combustion engine in the present embodiment is a diesel engine, and is simply referred to as “engine” below.

  As shown in FIG. 1, the engine 1 is provided with four cylinders # 1 to # 4. Four fuel injection valves 4 a to 4 d are attached to the cylinder head 2. These fuel injection valves 4a to 4d inject fuel into the combustion chambers of the corresponding cylinders # 1 to # 4. Also, the cylinder head 2 is provided with intake ports for introducing fresh air into the cylinders and exhaust ports 6a to 6d for discharging combustion gas to the outside of the cylinders corresponding to the respective cylinders # 1 to # 4. It has been.

  The fuel injection valves 4a to 4d are connected to a common rail 9 that accumulates high-pressure fuel. The common rail 9 is connected to the supply pump 10. The supply pump 10 sucks fuel in the fuel tank and supplies high-pressure fuel to the common rail 9. The high-pressure fuel supplied to the common rail 9 is injected into the cylinders # 1 to # 4 from the fuel injection valves 4a to 4d when the fuel injection valves 4a to 4d are opened.

  An intake manifold 7 is connected to the intake port. The intake manifold 7 is connected to the intake passage 3. An intake throttle valve 16 for adjusting the intake air amount is provided in the intake passage 3.

An exhaust manifold 8 is connected to the exhaust ports 6a to 6d. The exhaust manifold 8 is connected to the exhaust passage 26.
In the middle of the exhaust passage 26, there is provided a turbocharger 11 that supercharges intake air introduced into the cylinder using exhaust pressure. An intercooler 18 is provided in the intake passage 3 between the intake side compressor of the turbocharger 11 and the intake throttle valve 16. The intercooler 18 cools the intake air whose temperature has risen due to supercharging of the turbocharger 11.

  A first purification member 30 that purifies the exhaust gas is provided in the middle of the exhaust passage 26 and downstream of the exhaust side turbine of the turbocharger 11. Inside the first purification member 30, an oxidation catalyst 31 and a DPF catalyst 32 are arranged in series with respect to the flow direction of the exhaust gas.

  The oxidation catalyst 31 carries a catalyst for oxidizing HC in the exhaust. The DPF catalyst 32 is a filter that collects PM (particulate matter) in the exhaust gas and is made of a porous ceramic, and further supports a catalyst for promoting the oxidation of PM. . The PM in the exhaust gas is collected when it passes through the porous wall of the DPF catalyst 32.

  A fuel addition valve 5 for injecting fuel and supplying the fuel to the oxidation catalyst 31 and the DPF catalyst 32 is provided in the vicinity of the collecting portion of the exhaust manifold 8. The fuel addition valve 5 is connected to the supply pump 10 through a fuel supply pipe 27. The position of the fuel addition valve 5 may be changed as appropriate as long as it is in the exhaust system and upstream of the first purification member 30.

  A second purification member 40 that purifies the exhaust gas is provided in the middle of the exhaust passage 26 and downstream of the first purification member 30. Inside the second purification member 40, a selective reduction type NOx catalyst (hereinafter referred to as an SCR catalyst) 41 as an exhaust purification catalyst that reduces and purifies NOx in exhaust using ammonia as a reducing agent is disposed. .

  Further, a third purification member 50 for purifying exhaust gas is provided in the middle of the exhaust passage 26 and downstream of the second purification member 40. Inside the third purification member 50, an ammonia oxidation catalyst 51 for purifying ammonia in the exhaust is disposed.

  The engine 1 is provided with a urea water supply mechanism 200 that injects urea water into the exhaust passage 26 in order to supply ammonia as a reducing agent to the SCR catalyst 41. The urea water supply mechanism 200 includes a tank 210 for storing urea water, a urea addition valve 230 for injecting urea water into the exhaust passage 26, a supply passage 240 for connecting the urea addition valve 230 and the tank 210, and a tank for urea water. The pump 220 is sent from the 210 to the urea addition valve 230, and the level sensor 250 detects the remaining amount of urea water stored in the tank 210. The level sensor 250 is a detector that detects the remaining amount of urea water in the tank 210 by detecting a liquid level indicating the level of the level of urea water stored in the tank 210. Hereinafter, the sensor value of 250 is referred to as a level sensor value L. Further, the level sensor 250, the control device 80 and an acceleration sensor described later constitute an additive remaining amount calculating device.

  The urea addition valve 230 is provided in the exhaust passage 26 between the first purification member 30 and the second purification member 40, and its injection hole is directed to the SCR catalyst 41. When the urea addition valve 230 is opened, urea water is injected and supplied into the exhaust passage 26 via the supply passage 240. That is, urea water is added to the exhaust gas flowing through the exhaust passage 26 as an additive.

  The pump 220 is an electric pump, and at the time of forward rotation, the urea water is fed from the tank 210 toward the urea addition valve 230. On the other hand, during reverse rotation, urea water is sent from the urea addition valve 230 toward the tank 210. In other words, during the reverse rotation of the pump 220, urea water is recovered from the urea addition valve 230 and the supply passage 240 and returned to the tank 210.

  A dispersion plate 60 is provided in the exhaust passage 26 between the urea addition valve 230 and the SCR catalyst 41 to promote atomization of the urea water by dispersing the urea water injected from the urea addition valve 230. It has been.

  The urea water added from the urea addition valve 230 is changed into ammonia by hydrolysis using exhaust heat. This ammonia is adsorbed by the SCR catalyst 41. Then, NOx is reduced and purified by the ammonia adsorbed on the SCR catalyst 41.

  In addition, the engine 1 is provided with an exhaust gas recirculation device (hereinafter referred to as an EGR device). This EGR device is a device that reduces the combustion temperature in the cylinder by introducing a part of the exhaust gas into the intake air, thereby reducing the amount of NOx generated. The EGR device includes an EGR passage 13 that connects the intake passage 3 and the exhaust manifold 8, an EGR valve 15 provided in the EGR passage 13, an EGR cooler 14, and the like. By adjusting the opening degree of the EGR valve 15, the exhaust gas recirculation amount introduced into the intake passage 3 from the exhaust passage 26, that is, the so-called external EGR amount is adjusted. Further, the temperature of the exhaust gas flowing through the EGR passage 13 is lowered by the EGR cooler 14.

  Various sensors and switches for detecting the engine operating state are attached to the engine 1. For example, the air flow meter 19 detects the intake air amount GA in the intake passage 3. The throttle valve opening sensor 20 detects the opening of the intake throttle valve 16. The engine rotation speed sensor 21 detects the rotation speed of the crankshaft, that is, the engine rotation speed NE. The accelerator operation amount sensor 22 detects an accelerator pedal depression amount, that is, an accelerator operation amount ACCP. The outside air temperature sensor 23 detects the outside air temperature THout. The vehicle speed sensor 24 detects the vehicle speed SPD of the vehicle on which the engine 1 is mounted. The acceleration sensor outputs a signal corresponding to the acceleration of the vehicle and the inclination angle of the road surface, and the acceleration of the vehicle and the inclination state of the road surface are calculated based on the signal.

  In the present embodiment, two acceleration sensors, an acceleration sensor 25a that detects acceleration in the vehicle longitudinal direction and an acceleration sensor 25b that detects acceleration in the vehicle lateral direction, are provided. The acceleration sensor 25a outputs a positive value as a signal (hereinafter referred to as an acceleration sensor value GSa) when the vehicle is accelerating or when the traveling road surface is uphill. On the other hand, the acceleration sensor 25a outputs a negative value as the acceleration sensor value GSa when the vehicle is decelerating or when the traveling road surface is on a downward slope. The acceleration sensor 25b is positive as a signal (hereinafter referred to as an acceleration sensor value GSb) when the vehicle is turning to the left or when the road surface is inclined so that the left side of the vehicle is high and the right side of the vehicle is low. Output the value. On the other hand, when the vehicle is turning right, or when the traveling road surface is tilted so that the right side of the vehicle is high and the left side of the vehicle is low, a negative value is output as the acceleration sensor value GSb. Therefore, when the vehicle is traveling on a flat road with almost no gradient at a constant speed, or when the vehicle is stopped on a flat road with little gradient, the acceleration sensor values GSa and GSb are both values near “0”. become.

  The first exhaust temperature sensor 100 provided upstream of the oxidation catalyst 31 detects the first exhaust temperature TH1 that is the exhaust temperature before flowing into the oxidation catalyst 31. The differential pressure sensor 110 detects the pressure difference ΔP between the exhaust pressure upstream and downstream of the DPF catalyst 32.

  A second exhaust temperature sensor 120 and a first NOx sensor 130 are provided in the exhaust passage 26 between the first purification member 30 and the second purification member 40 and upstream of the urea addition valve 230. The second exhaust temperature sensor 120 detects a second exhaust temperature TH2, which is the exhaust temperature before flowing into the SCR catalyst 41. The first NOx sensor 130 detects a first NOx concentration N1, which is the NOx concentration in the exhaust before flowing into the SCR catalyst 41.

  The exhaust passage 26 downstream of the third purification member 50 is provided with a second NOx sensor 140 that detects a second NOx concentration N2 that is the NOx concentration in the exhaust gas that has passed through the SCR catalyst 41.

  Outputs from these various sensors are input to the control device 80. The control device 80 includes a central processing control device (CPU), a read-only memory (ROM) that stores various programs and calculation maps in advance, a random access memory (RAM) that temporarily stores calculation results of the CPU, a timer counter, The microcomputer is mainly configured with an input interface, an output interface, and the like.

  Then, the controller 80 controls, for example, the fuel injection amount control / fuel injection timing control of the fuel injection valves 4a to 4d and the fuel addition valve 5, the discharge pressure control of the supply pump 10, and the drive amount of the actuator 17 that opens and closes the intake throttle valve 16. Various controls of the engine 1 such as control and opening control of the EGR valve 15 are performed.

  The control device 80 performs urea water addition control by the urea addition valve 230 as one of exhaust purification control. In this addition control, a target addition amount QE that is a target value of the urea addition amount necessary for reducing the NOx discharged from the engine 1 is calculated based on the engine operating state and the like. Then, the valve opening state of the urea addition valve 230 is controlled so that urea water corresponding to the target addition amount QE is injected from the urea addition valve 230.

In addition, the control device 80 calculates the remaining amount of urea water stored in the tank 210, and notifies the remaining amount of urea water based on the calculated remaining amount.
Here, it is the alarm device 12 connected to the control device 80 that executes this notification. The notification device 12 receives a notification processing execution command from the control device 80, and performs notification such as a warning for urging the driver to replenish urea water through sound, light, or display on a meter panel. To do.

  Incidentally, as described above, the level sensor 250 for detecting the liquid level of the urea water is provided in the tank 210. The level sensor value L is determined based on the bias of the urea water in the tank 210, the inclination of the liquid level, and the like. Affected by.

  For example, as shown in FIGS. 2A and 2B, the level sensor 250 includes a float 251 that moves in accordance with a change in the liquid level. The level sensor 250 detects the height of the liquid level based on the position of the float 251. As shown by the solid line in FIG. 2A, when the remaining amount of urea water in the tank 210 is small, the float 251 is at a low position, and the level sensor value L becomes a small value. Further, as shown by a broken line in FIG. 2A, urea water is biased to one side in the tank 210 due to acceleration / deceleration of the vehicle or inclination of the vehicle, and when the liquid level is inclined, the urea sensor is placed at a position touching the level sensor 250. Water disappears. At this time, since the float 251 is at the lowest position, the level sensor value L is a value indicating that the height of the liquid level is the lowest, that is, “0” even though urea water remains in the tank 210. "Become.

  On the other hand, when a large amount of urea water is stored in the tank 210 as shown by a solid line in FIG. 2B and the tank 210 is almost filled with urea water, the position of the float 251 is high. The level sensor value L is at a large value. At this time, even if the urea water is biased to one side in the tank 210 due to acceleration / deceleration of the vehicle or the inclination of the vehicle, as shown by a broken line in FIG. Is kept in contact with the level sensor 250, and the urea water does not disappear at the position where the level sensor 250 is touched. This is because when the tank 210 is filled with urea water, the urea water is hardly biased even if the liquid level is inclined. In this way, since the urea water is hardly biased, the level sensor value L continues to maintain a large value at this time.

  As described above, the magnitude of the influence of the bias of urea water or the inclination of the liquid level in the tank 210 on the level sensor value L, which is the liquid level detected by the level sensor 250, is stored in the tank 210. It changes depending on the remaining amount of urea water. Moreover, the mode of the change depends on the shape of the tank 210 storing the urea water.

Next, the shape of the tank 210 will be described with reference to FIG.
FIG. 3A schematically shows the shape of the tank 210 as viewed from above the vehicle. Note that the directions of the arrow Fr, arrow Rr, arrow Rh, and arrow Lh in FIG. 3A indicate four directions of the vehicle front, the vehicle rear, the vehicle right side, and the vehicle left side, respectively. When viewed from above the vehicle, the tank 210 has an asymmetric shape both in the longitudinal direction of the vehicle and in the lateral direction of the vehicle. The reason why the tank 210 is asymmetrical in this way is that there is a limit to the mounting space in the vehicle, and the shape is restricted when attempting to secure the capacity of the tank 210. The level sensor 250 is also installed at a position slightly deviated from the center of the tank 210 due to restrictions on mounting.

  FIG. 3B schematically shows the shape of the tank 210 viewed from the left side of the vehicle. Note that the directions of the arrow Fr, the arrow Rr, the arrow Up, and the arrow Lo in FIG. 3B indicate four directions of the vehicle front, the vehicle rear, the vehicle upper, and the vehicle lower, respectively. When viewed from the left side of the vehicle, the tank 210 is a thin tank that is long in the vehicle front-rear direction and low in height. It can also be seen that the tank 210 has an asymmetric shape in the vehicle longitudinal direction.

  FIG. 3C schematically shows the shape of the tank 210 as viewed from the front of the vehicle. Note that the directions of the arrow Rh, the arrow Lh, the arrow Up, and the arrow Lo in FIG. 3C indicate four directions of the vehicle right side, the vehicle left side, the vehicle upper side, and the vehicle lower side, respectively. As can be seen from FIG. 3C, the level sensor 250 is installed at a position slightly deviated from the center of the tank 210.

  Next, the relationship among the vehicle inclination angle (horizontal, 20 degrees, 10 degrees, and 5 degrees), the level sensor value L, and the actual remaining amount of urea water will be described with reference to FIGS. Here, FIG. 4A shows the relationship when the vehicle is leaning forward (inclined state where the front of the vehicle is higher than the rear of the vehicle), and FIG. 4B is the graph when FIG. The above relationship is shown in an inclined state where the height is higher than that. FIG. 5 (a) shows the above relationship when the vehicle is tilted upward to the left (inclined state where the left side of the vehicle is higher than the right side of the vehicle), and FIG. 5 (b) is the graph when FIG. The relationship is shown in an inclined state that is higher than that on the left side. 4 and 5, the level sensor values L are “2”, “4”, “6”, “8”, and “10” in a state where the vehicle is stopped at each inclination angle. When urea water is put into the tank 210 until the value is reached, the amount of urea water actually entered, that is, the tank storage amount in the tank 210 is plotted as an actual remaining amount. The graphs of FIGS. 4 and 5 merely show the characteristics of the tank 210. Naturally, the characteristics differ depending on the shape of the tank.

  As shown in FIG. 4A, at the time of forward ascending, the actual remaining amount corresponding to each level sensor value L tends to increase as the inclination angle increases, and as the inclination angle increases, the actual remaining amount in the horizontal state increases. Deviation from quantity. Further, in a region where the actual remaining amount is relatively large, the difference between the actual remaining amount when horizontal and the actual remaining amount when tilting is small. In addition, when the level sensor value L becomes each value of “2” to “10” at the time of forward tilt, the actual remaining amount at the time of inclination is always the actual remaining amount at the time of leveling. It has characteristics that exceed. The reason for this is that, as shown in FIG. 3, the tank 210 has an asymmetric shape in the front-rear direction, and in particular, the capacity behind the level sensor 250 in the tank 210 is greater than the capacity ahead of the level sensor 250. This is because many are formed. That is, the urea water is biased toward the rear of the level sensor 250 when the vehicle is tilted forward, and the urea water that touches the level sensor 250 is reduced. Since this tendency becomes more prominent as the inclination angle increases, the characteristic is as shown in FIG.

  As shown in FIG. 4 (b), the actual remaining amount corresponding to each level sensor value L tends to increase as the tilt angle increases, and the level increases as the tilt angle increases. Deviate from the actual remaining amount. However, unlike the case of forward tilting, the actual remaining amount at the time of tilting does not always exceed the actual remaining amount at the time of leveling. Specifically, when the level sensor value L is “8”, the actual remaining amount is almost the same at the time of leveling and tilting, and when the level sensor value L is “10”, the actual remaining amount at the time of tilting is level. Less than the actual remaining amount. This is because the portion of the tank 210 in front of the level sensor 250 has a smaller capacity than the portion behind the level sensor 250. As a result, in the case of a slope that rises backward, when the actual remaining amount of urea water is small, the urea water that touches the level sensor 250 is reduced if the urea water is biased to a portion in front of the level sensor 250 of the tank 210. However, when the actual remaining amount of urea water is large, the portion ahead of the level sensor 250 is filled with urea water, and the amount of urea water that touches the level sensor 250 increases. Since such a tendency becomes more prominent as the inclination angle increases, the characteristics shown in FIG. 4B are obtained.

  As shown in FIG. 5 (a), the same tendency as that of the rearward rising slope is shown during the upward slope. That is, when the level sensor value L is “2”, the actual remaining amount when tilting exceeds the actual remaining amount when leveling, whereas the level sensor value L is “6”, “8”, “10”. In the case of, the actual remaining amount when tilting is lower than the actual remaining amount when leveling. This is because the tank 210 is formed such that the left side of the level sensor 250 has a smaller capacity than the right side of the level sensor 250.

  As shown in FIG. 5 (b), the same tendency as that of the forward rising inclination is shown during the upward rising inclination. That is, the actual remaining amount corresponding to each level sensor value L tends to increase as the tilt angle increases, and deviates from the actual remaining amount in the horizontal direction as the tilt angle increases. The reason is that the tank 210 is formed with a smaller capacity in the portion located on the right side of the level sensor 250 than in the portion located on the left side of the level sensor 250, as in the case of the upward slope.

  The control device 80 considers the change in the magnitude of the influence of the bias of urea water in the tank 210 on the level sensor value L due to the difference in the remaining amount of urea water, and the remaining urea water amount NR in the tank 210. Update. When the urea water remaining amount NR is small, the vehicle driver is notified of the urea water remaining amount. Hereinafter, the process of performing the update of the urea water remaining amount NR and the notification regarding the remaining amount will be described. This process is executed by the control device 80 at predetermined intervals.

  As shown in FIG. 6, when this process is started, it is determined whether or not the level sensor value L is stable (S100). Here, it is determined that the level sensor value L is stable when the state in which the fluctuation range of the level sensor value L is smaller than the predetermined value H1 continues for the predetermined time T1 or longer. The predetermined value H1 and the predetermined time T1 are set in advance to determine whether the level sensor value L is stable.

  When the level sensor value L is not stable (S100: NO), the current level sensor value L is smoothed to calculate the post-smoothing level sensor value LN (S200).

  After calculating the level sensor value LN after the annealing process, the urea water remaining amount NR is calculated with reference to the level sensor value LN after the annealing process (S210). Here, the level sensor value LN after the annealing process may be used as the urea water remaining amount NR as it is, or a value obtained by adding various corrections to the level sensor value LN after the annealing process is used. NR may be used.

  On the other hand, when the level sensor value L is stable (S100: YES), it is determined whether or not the acceleration sensors 25a and 25b are functioning normally (S110). This determination is performed by normal acceleration sensor normal determination means such as disconnection determination or detection of an abnormal signal.

  When it is determined that the acceleration sensors 25a and 25b are functioning normally (S110: YES), it is determined whether the vehicle is rapidly accelerating or decelerating (S300). In step S300, it is determined whether the vehicle is rapidly accelerating or decelerating using, for example, the change amount of the accelerator operation amount ACCP, the brake depression amount, the change amount of the vehicle speed SPD, or the like.

  When it is determined that neither rapid acceleration nor rapid deceleration is performed (S300: NO), acceleration determination values B, C, X, and Y are calculated based on the level sensor value L (S310). The acceleration determination values B, C, X, and Y correspond to accelerations detected when the vehicle is tilted forward, backward, tilted to the left, and tilted to the right, respectively, and the level sensor value L is used as an argument. Calculated. It should be noted that the acceleration range defined in steps S320 and S330, which will be described later, using these acceleration determination values B, C, X, and Y is calculated with reference to the level sensor value L. This is the execution range to be executed.

  Here, FIGS. 7A and 7B show calculation maps showing the relationship between the acceleration determination values B and C and the level sensor value L as an argument. The acceleration determination values Y and X and the level sensor value as an argument are shown in FIGS. The calculation maps showing the relationship with L are shown in FIGS. 8 (a) and 8 (b). 7A and 7B is based on the relationship shown in FIGS. 4A and 4B, and the operation maps in FIGS. 8A and 8B are those shown in FIG. , (B) are calculated based on the relationship shown in FIG.

Here, a specific calculation method will be described with reference to FIGS. 4 (a) and 7 (a).
First, as shown by a broken line in FIG. 4A, an allowable range of the actual remaining amount error is set around a line indicating the relationship between the level sensor value L of the urea water in the horizontal state and the actual remaining amount. Next, the actual remaining amount of urea water with respect to the level sensor value L plotted at each inclination angle is referred to, and the inclination angle at which the actual remaining amount falls within the allowable range of the actual remaining amount error is determined for each level sensor value L. In this embodiment, since there are only three types of inclination angles of 20 degrees, 10 degrees, and 5 degrees, the distance on the graph between the boundary value of the allowable range of the actual remaining amount error and the actual remaining amount at the inclination angle. In consideration of the above, an inclination angle that falls within an allowable range of the actual remaining amount error is determined. However, the present invention is not limited to this, for example, the relationship between the level sensor value L and the actual remaining amount is measured based on the above three or more types of inclination angles, and the actual remaining amount calculated by referring to each level sensor value L is An inclination angle that falls within an allowable range of the actual remaining amount error may be determined. By determining the inclination angle that falls within the allowable range of the actual remaining amount error by such means, the condition can be set with higher accuracy.

  After calculating the inclination angle at which the actual remaining amount corresponding to the level sensor value L falls within the allowable range of the actual remaining amount error, this is converted into an acceleration determination value. Assuming a constant speed running or a vehicle stop state, the relationship between the vehicle inclination angle and the acceleration in each direction component detected by the acceleration sensors 25a and 25b is uniquely determined using a trigonometric function. Therefore, in this embodiment, the value which converted the inclination angle into the acceleration determination value from the relationship is employ | adopted.

  After converting the inclination angle at which the actual remaining amount corresponding to the level sensor value L falls within the allowable range of the actual remaining amount error into the acceleration determination value, this is plotted as shown in FIG. An arithmetic map showing the relationship between the acceleration determination value B and the level sensor value L as an argument is completed by connecting the points. The calculation maps of FIGS. 7B, 8A, and 8B can be calculated based on FIGS. 4B, 5A, and 5B, respectively, by a similar procedure. In both of the calculation maps shown in FIG. 7 and FIG. 8, when the level sensor value L is less than “2” and is in the vicinity of “0” which is the lowest value, the level sensor value L is “8” or more. Compared to the case of, the acceleration judgment value is a small absolute value. That is, when it is considered that the remaining amount of urea water in the tank 210 is small, the acceleration determination value is set to a small absolute value as compared with the case where a large amount of urea water is stored in the tank 210. This is because, when the urea water remaining amount is small, if the urea water is biased to one side in the tank 210 due to the inclination of the liquid level, the urea water hardly exists at a position where the level sensor 250 is touched, and the urea is not contained in the tank. This is because the level sensor value L may be detected at the lowest value even though water remains.

  If “8” is the first level threshold and “2” is the second level threshold, setting the acceleration determination value in this way means that the level sensor value L is greater than or equal to the first level threshold. Sometimes, the execution range is set wider than when the level sensor value L is less than the second level threshold.

  After the acceleration determination values B, C, X, and Y are calculated, whether or not the acceleration sensor value GSa that is the acceleration detection value in the vehicle longitudinal direction is greater than the acceleration determination value C and smaller than the acceleration determination value B. Is determined (S320). The acceleration determination value C is set as a negative value and the acceleration determination value B is set as a positive value in accordance with the acceleration direction of the vehicle.

  When the acceleration sensor value GSa is larger than the acceleration determination value C and smaller than the acceleration determination value B (S320: YES), the acceleration sensor value GSb that is an acceleration detection value in the vehicle lateral direction is greater than the acceleration determination value Y. It is determined whether it is larger and smaller than the acceleration determination value X (S330). The acceleration determination value Y is set as a negative value and the acceleration determination value X is set as a positive value in accordance with the acceleration direction of the vehicle. Here, an execution range in which the calculation process for calculating the remaining amount is performed with reference to the level sensor value L in the present embodiment will be described. The execution range means that the acceleration sensor value GSa is larger than the acceleration determination value C and smaller than the acceleration determination value B, and the acceleration sensor value GSb is larger than the acceleration determination value Y and larger than the acceleration determination value X. This is a small acceleration range and is defined by acceleration judgment values B, C, X, and Y.

  When the acceleration sensor value GSb is larger than the acceleration determination value Y and smaller than the acceleration determination value X (S330: YES), a calculation process for calculating the urea water remaining amount NR with reference to the level sensor value L is executed. By doing so, the urea water remaining amount NR is updated (S340). In this calculation process, a configuration may be employed in which the urea water remaining amount NR is calculated by multiplying the level sensor value L by a coefficient, or by reading the urea water remaining amount from the map using the level sensor value L as an argument. . Further, the urea water remaining amount NR may be calculated by adding various corrections to the urea water remaining amount calculated from the detected level sensor value L. Further, after determining whether the urea water remaining amount calculated with reference to the level sensor value L is used for calculating the urea water remaining amount NR based on another condition, the urea water remaining amount NR is calculated. This calculation process is included. The calculation process executed with reference to the level sensor value L corresponds to the remaining amount calculation process referring to the liquid level detected by the level sensor in the present embodiment.

  On the other hand, at the time of sudden acceleration or sudden deceleration (S300: YES), when the acceleration sensor value GSa is equal to or less than the acceleration determination value C, or when the acceleration sensor value GSa is equal to or greater than the acceleration determination value B (S320: NO), the acceleration sensor value GSb. Is not greater than the acceleration determination value Y, or when the acceleration sensor value GSb is not less than the acceleration determination value X (S330: NO), the process of step S420 is performed. In this step S420, a value obtained by subtracting the added amount integrated value NS from the urea water remaining amount NR (that is, the urea water remaining amount NR updated last time) before being updated by the current process execution is set as the urea water remaining amount NR. Thus, the urea water remaining amount NR is updated. The added amount integrated value NS is the total amount of urea water added from the last update of the urea water remaining amount NR until the current urea water remaining amount NR is updated. For example, the target added amount QE is integrated. It is calculated by doing. When the urea water remaining amount NR is updated, the addition amount integrated value NS is reset to “0”, and the urea water addition amount integration process is started again. The process of calculating a value obtained by subtracting the added amount integrated value NS from the urea water remaining amount NR updated last time is a process of calculating the remaining amount by subtracting the added amount integrated value from the previously calculated remaining amount. It corresponds to.

  When it is determined in step S110 that the acceleration sensors 25a and 25b are not functioning normally, that is, an abnormality has occurred in the acceleration sensors 25a and 25b, it is determined whether or not the vehicle is stopped (S400). ). In step S400, when the vehicle speed SPD is “0”, it is determined that the vehicle is stopped. In the stop determination in step S400, when the vehicle speed SPD is a very low speed near “0”, the vehicle may be regarded as being stopped.

When it is determined that the vehicle is stopped (S400: YES), the process of step S420 is executed, and the urea water remaining amount NR is updated.
On the other hand, when it is determined that the vehicle is traveling (S400: NO), it is determined whether or not the level sensor value L is stable for a long time (S410). In step S410, it is determined that the level sensor value L is stable for a long period of time when the fluctuation range of the level sensor value L is kept below the predetermined value H2 for a predetermined time T2 or longer. . The predetermined value H2 and the predetermined time T2 are used to determine that the level sensor value L is stable for a long time to such an extent that it can be determined that the vehicle is traveling on a flat road at a constant speed. Appropriate values are preset. In particular, for the predetermined time T2, a time longer than the predetermined time T1 is set.

When the level sensor value L is stable for a long time (S410: YES), the process of step S340 is executed, and the urea water remaining amount NR is updated.
On the other hand, when the level sensor value L has not been stable for a long time (S410: NO), the process of step S420 is executed, and the urea water remaining amount NR is updated.

  When the urea water remaining amount NR is updated in any of Step S210, Step S340, and Step S420, it is determined whether or not the latest urea water remaining amount NR after the update is equal to or less than the threshold value α ( S500). As the threshold value α, based on the fact that the remaining urea water amount NR is less than or equal to the threshold value α, the remaining urea water amount NR is reduced to such an extent that the driver must be notified of the remaining amount of urea water. A value that can be determined to be present is preset.

When the urea water remaining amount NR exceeds the threshold value α (S500: NO), this process is temporarily terminated.
On the other hand, when the urea water remaining amount NR is less than or equal to the threshold value α (S500: YES), a notification process for the driver or the like is executed (S510), and this process is temporarily terminated. When this notification process is executed, the notification device 12 gives a warning, such as prompting the urea water to be replenished.

  Through the series of processes as described above, the control device 80 functions as a calculation unit that calculates the remaining amount of additive in the tank 210 and also functions as a storage unit that stores the remaining amount of additive calculated by the calculation unit. .

Next, the operation of the above series of processes will be described.
In step S100, whether or not the level of the urea water stored in the tank 210 is stable without being greatly shaken by determining whether or not the level sensor value L is stable without greatly fluctuating. Is determined. When the level sensor value L is stable without largely fluctuating (S100: YES), the level sensor value L is in a state suitable for detection of the remaining urea water amount NR based on the level sensor value L. It is judged that

  On the other hand, if the level sensor value L fluctuates greatly and is not stable (S100: NO), the level sensor value L is subjected to an annealing process in step S200, and the level after the annealing process is performed. A sensor value LN is calculated. Thereafter, the urea water remaining amount NR is calculated based on the level sensor value LN after the annealing process in step S210, so that even if the level sensor value L varies greatly and is not stable, the urea water The remaining amount NR is calculated.

  By the way, the influence of the inclination of the vehicle on the level sensor value L varies depending on the remaining amount of urea water stored in the tank 210. Therefore, depending on the remaining amount of urea water stored in the tank 210, there is a possibility that an accurate value cannot be calculated even if the calculation process of the remaining urea water amount NR is executed with reference to the level sensor value L. .

  On the other hand, in this embodiment, acceleration determination values B, C, Y, and X are calculated based on the level sensor value L in step S310. When it is determined in steps S320 and S330 that the detected acceleration values in the vehicle longitudinal direction and the vehicle lateral direction are all within the execution range defined by the acceleration determination values B, C, X, and Y, Based on the level sensor value L, a urea water remaining amount NR calculation process is executed in step S340. That is, even if the remaining amount of urea water changes, it is possible to set an execution range that takes into account the change in the remaining amount, and the acceleration detected by the acceleration sensors 25a and 25b is within the set execution range. Whether or not to execute the remaining amount calculation process with reference to the detected level sensor value L is determined according to whether or not it is detected.

  Further, the acceleration determination values B, C, Y, and X in step S310 of the present embodiment are considered to be near “0” where the level sensor value L is the lowest, that is, the remaining amount of urea water in the tank 210 is small. In this case, the acceleration determination value is set to a small value as compared with the case where the level sensor value L is high, that is, when a large amount of urea water is stored in the tank 210. That is, the execution range is set wider when a large amount of urea water is stored as compared with a case where the urea water is considered to be small.

  Further, the acceleration determination values B, C, Y, and X in step S310 are tolerances for errors in which a deviation between the actual remaining amount of urea water in the horizontal state and the remaining amount of urea water NR calculated from the level sensor value L is set. An inclination angle that falls within the range is determined, and an acceleration determination value is calculated from the inclination angle. Since the calculation process with reference to the level sensor value L is to calculate the urea water remaining amount NR from the level sensor value L on the assumption that the level is horizontal, the urea water remaining amount NR calculated from the level sensor value L in the horizontal state. Corresponds to the actual remaining amount.

  Therefore, by setting the acceleration determination value in this way, the execution range in which the upper limit and the lower limit are set by the acceleration determination values B, C, Y, and X is calculated as the urea water remaining amount NR calculated through the calculation process. This is the acceleration range where the deviation from the actual remaining amount falls within a certain range, that is, the acceleration range where the error of the urea water remaining amount NR falls within the certain range.

  When it is determined through steps S320 and S330 that the error of the urea water remaining amount NR falls within a certain range, a remaining amount calculation process referring to the level sensor value L is performed in step S340.

  In step S420, when the urea water remaining amount NR is updated, the addition amount integrated value NS is subtracted from the urea water remaining amount NR updated last time. That is, the current level sensor value L is not involved in updating the urea water remaining amount NR. Therefore, even when the remaining amount calculation process referring to the level sensor value L is not executed (S300: YES, S320: NO, S330: NO), the added amount integrated value NS is calculated from the previous urea water remaining amount NR. The remaining amount is calculated by subtraction.

  In step S500, after the urea water remaining amount NR is updated in any of step S210, step S340, and step S420, it is determined whether or not the latest urea water remaining amount NR after the update is equal to or less than the threshold value α. When the determination is made and the urea water remaining amount NR is less than or equal to the threshold value α (S500: YES), a notification process for the driver or the like is executed. As a result, when the urea water remaining amount NR is reduced to the extent that the notification process regarding the remaining amount of urea water must be performed for the driver, the notification process is executed for the driver.

  Further, when an abnormality occurs in the acceleration sensors 25a and 25b, the acceleration determination using the acceleration sensor values GSa and GSb executed in step S310 and step S320 cannot be performed. Therefore, when it is determined in step S110 that an abnormality has occurred in the acceleration sensors 25a and 25b (S110: NO), the urea water level is stabilized in a horizontal state by the determination process in step S400 or step S410. Judging whether or not. Thereby, even if abnormality has arisen in acceleration sensor 25a, 25b, urea water residual quantity NR is updated appropriately in step S340.

  Further, when the acceleration determination using the acceleration determination values B, C, Y, and X is executed in steps S320 and S330 while the vehicle is rapidly accelerating or decelerating, the acceleration determination values B and C in the present embodiment are used. , Y, and X are values that are set assuming a vehicle at the time of stoppage, and may cause erroneous determination. In this regard, in the present embodiment, when the vehicle is suddenly accelerated or decelerated in step S300, steps S320 and S330 are not executed.

According to the embodiment described above, the following effects can be obtained.
(1) When the vehicle tilts, the inclination of the acceleration sensors 25a and 25b with respect to the vertical direction also changes. Therefore, the direction of gravity acting on the acceleration sensors 25a, 25b changes according to the inclination of the vehicle, and the acceleration sensor values GSa, GSb detected by the acceleration sensors 25a, 25b change according to the inclination of the vehicle. Therefore, by referring to the magnitudes of the acceleration sensor values GSa and GSb, the inclination of the vehicle, that is, the inclination of the tank 210 storing the urea water can be grasped.

  In the above embodiment, using this relationship, an execution range using acceleration as an index is set, and when the acceleration sensor values GSa and GSb are within the execution range, the level sensor value L detected by the level sensor 250 is referred to. Then, a calculation process for calculating the remaining amount of urea water is executed. As a result, the bias of urea water in the tank 210 has a large influence on the detection value of the level sensor 250, and the level sensor value L is set in a situation where the remaining amount of urea water cannot be appropriately calculated by the level sensor value L. It can suppress that the calculation process to refer is performed.

  In order to calculate the remaining amount with high accuracy, the level sensor value L is referred only when the difference between the urea water remaining amount NR calculated from the level sensor value L and the actual remaining amount becomes very small. If a narrow execution range is set so that the calculation process to be performed is performed, the calculation process becomes difficult to execute. On the other hand, if a wide execution range is set in order to secure the execution opportunity of the calculation process, the level is also obtained when the difference between the urea water remaining amount NR calculated from the level sensor value L and the actual remaining amount becomes large. The calculation process referring to the sensor value L is executed, and the calculation accuracy of the urea water remaining amount NR is lowered. Therefore, when setting the execution range, it is necessary to set an execution range having an appropriate width in accordance with the degree of influence of the vehicle inclination on the level sensor value L that is the detection value of the level sensor 250.

  However, the influence of the vehicle inclination on the level sensor value L changes according to the remaining amount of urea water. Therefore, even if the optimized execution range is set so that it becomes the optimal size when the remaining amount is the predetermined amount, if the remaining amount changes due to the consumption of urea water, the execution range will not be appropriate. End up.

  On the other hand, in the above embodiment, the execution range is set according to the level sensor value L detected by the level sensor 250. Therefore, even if urea water is consumed and the remaining amount of urea water changes, an execution range that takes into account the change in the remaining amount is set each time. Therefore, it is possible to suppress the execution range from becoming inappropriate due to a change in the remaining amount of urea water.

  That is, according to the above embodiment, even if the remaining amount of urea water stored in the tank 210 changes, the remaining amount of urea water is preferably determined using the level sensor value L that is the detection value of the level sensor 250. Can be calculated.

  (2) In setting the acceleration determination values B, C, Y, and X, it is considered that the level sensor value L is in the vicinity of “0” which is the lowest value, that is, the remaining amount of urea water in the tank 210 is small. In this case, the acceleration determination value is set to a small value as compared with the case where the level sensor value L is high, that is, when a large amount of urea water is stored in the tank 210. As a result, when the level sensor value L is equal to or greater than “8”, which is the first level threshold value, the execution range is set wider than when the level sensor value L is less than “2”, which is the second level threshold value. Is done.

  Therefore, the remaining amount of the urea water stored in the tank 210 is small, and the level sensor value L is a value indicating that the liquid level is the lowest even though the urea water remains in the tank 210. It is possible to prevent the remaining amount from being calculated with reference to the level sensor value L in a state where there is a possibility of becoming “0”. On the other hand, even if the remaining amount of urea water stored in the tank is large and the vehicle is tilted, the level is considered to be present when the additive is present at the position touching the level sensor 250. An opportunity to calculate the remaining amount with reference to the sensor value L can be secured.

  (3) When the calculated latest urea water remaining amount NR is equal to or less than the threshold value α, a notification process for the driver or the like is executed. As a result, when the urea water remaining amount NR is reduced to the extent that the notification processing regarding the remaining amount of urea water must be performed for the driver, the notification processing can be executed for the driver. .

  (4) When the remaining amount calculation process referring to the level sensor value L is not executed, it is added during the period from the last update of the urea water remaining amount NR to the current update of the urea water remaining amount NR By subtracting the total amount of the additive from the urea water remaining amount NR updated last time, the urea water remaining amount NR is calculated. Thus, even when the remaining amount calculation process referring to the level sensor value L is not executed, the urea water remaining amount NR is calculated by subtracting the addition amount integrated value NS from the previous urea water remaining amount NR. be able to.

  (5) Acceleration determination values B, C, Y, and X are determined as tilt angles that fall within an allowable error range set with respect to the actual remaining amount of urea water in a horizontal state. The calculated value is set. Therefore, by setting the acceleration determination value in this way, when it is determined that the error of the urea water remaining amount NR falls within a certain range, a remaining amount calculation process that refers to the level sensor value L is performed. Thus, it is possible to suppress the calculation of the urea water remaining amount NR including a large error exceeding a certain range.

  (6) In addition, the acceleration determination values B, C, Y, and X are set by a calculation map that is read using the level sensor value L as an argument. Accordingly, when the acceleration determination value suitable for the detected level sensor value L is set from the calculation map, the level sensor value L is referred to when it is determined that the error of the urea water remaining amount NR falls within a certain range. The remaining amount calculation process can be performed.

  (7) Remaining amount referring to the level sensor value L based on the acceleration detection value in two directions of the acceleration sensor value GSa that is the acceleration detection value in the vehicle longitudinal direction and the acceleration sensor value GSb that is the acceleration detection value in the vehicle left-right direction. It is determined whether or not the calculation process can be executed. Therefore, the pitching and rolling of the vehicle can be detected by the acceleration sensors 25a and 25b.

  Therefore, as compared with the case of determining whether or not to execute the remaining amount calculation process that refers to the level sensor value L based on the acceleration in one direction, the influence of the inclination of the vehicle on the level sensor value L is more accurately considered. Thus, the remaining amount calculation process referring to the level sensor value L can be executed.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, the values calculated from the operation maps shown in FIGS. 7 and 8 are used as the acceleration determination values B, C, Y, and X in step S310 in FIG. May be adopted. As an example, the calculation map of FIG. 9 is shown.

The calculation map shown in FIG. 9 is a table showing acceleration determination values B, C, Y, and X with respect to the level sensor value L as an argument. 7 and 8 is that the level sensor value L is defined as a constant value for each numerical range. For example, when the level sensor value L that is an argument is in the numerical range of “2 ≦ L <4”, 1.00 m / s ² is calculated as the acceleration determination value B. Similar to the calculation maps of FIGS. 7 and 8, these numerical values are calculated from the inclination angles that fall within the allowable error range set for the actual remaining amount of urea water in the horizontal direction from FIGS. An acceleration determination value is calculated and set.

  In step S310, different acceleration determination values B, C, Y, and X are adopted for the vehicle longitudinal acceleration and the vehicle lateral acceleration, respectively. However, the present invention is not limited to this. You may define execution ranges in all directions. As an example in which this modified example is adopted, the shape of the tank is formed symmetrically in the front-rear and left-right directions, and the level sensor is installed at the center position of the tank. A case where the influence of the tilt angle or acceleration does not depend, or a case where the influence degree is small is considered.

  -Moreover, although the calculation map of this embodiment was shown in FIG.7, 8, it is not necessarily required to employ | adopt the same calculation map. Various calculation maps can be used depending on the shape of the tank. In addition, when creating the calculation map, as shown in FIGS. 4 and 5, by appropriately measuring the characteristics according to the vehicle inclination angle, the calculation map in accordance with the shape of the tank can be obtained using the calculation method described above. It is possible to create.

  In step S300, it is determined whether or not sudden acceleration or sudden deceleration has occurred. However, this process need not necessarily be performed. For example, when a certain amount of acceleration / deceleration of the vehicle may be permitted, the process of step S300 may be omitted.

  The notification process for the driver or the like is executed when the calculated latest urea water remaining amount NR is equal to or less than the threshold value α. However, the notification process is not necessarily executed. For example, the urea water remaining amount NR is changed with reference to the calculated urea water remaining amount NR, the urea water remaining amount NR is judged from the urea water remaining amount NR, and the subsequent engine start is prohibited. Various modifications may be employed such as determining that the replenishment of urea water is completed from the NR, or canceling the notification process after the completion of replenishment.

  Calculation of the remaining amount referring to the level sensor value L based on the acceleration sensor value GSa which is the acceleration sensor value GSa which is the acceleration detection value in the vehicle longitudinal direction and the acceleration sensor value GSb which is the acceleration detection value in the vehicle left-right direction. Although it is determined whether or not the process can be executed, it is not always necessary to determine based on the acceleration sensor value in two directions. That is, whether or not the remaining amount calculation process referring to the level sensor value L can be executed may be determined based on only one of step S320 and step S330. In this case, only the necessary threshold value may be calculated as the acceleration determination value in step S310.

  -Although the direction of the acceleration to detect is two directions of the vehicle front-back direction and the left-right direction, it does not necessarily need to be restricted to that. For example, it may be configured to detect accelerations in two directions that are perpendicular to the vertical direction of the vehicle and are orthogonal to each other, and to calculate the front-rear and left-right accelerations from the accelerations in these two directions. Moreover, you may comprise so that the acceleration of a 2nd direction perpendicular | vertical with respect to a certain 1st direction and a 1st direction may be detected. In detecting the pitching or rolling of the vehicle, it is preferable to detect the acceleration in two directions that are perpendicular to the vertical direction of the vehicle and are orthogonal to each other.

  -Although the acceleration sensor in this embodiment showed two embodiment provided with the acceleration sensor 25a which detects the vehicle front-back direction, and the acceleration sensor 25b which detects a vehicle left-right direction, it is not restricted to this, For example, the acceleration of multiple directions is shown. You may change so that the acceleration sensor which can be detected is provided.

  When the first level threshold is set to “8”, the second level threshold is set to “2”, and the level sensor value L is greater than or equal to the first level threshold, the level sensor value L is less than the second level threshold. Compared to the above, the configuration in which the execution range is set wider is illustrated. On the other hand, the value of each level threshold value can be changed as appropriate. At least when the level sensor value L is greater than or equal to the first level threshold value, the execution range may be set wider than when the level sensor value L is less than the second level threshold value that is smaller than the first level threshold value. If such a configuration is adopted, the level sensor value L may become “0”, which is a value indicating that the liquid level is the lowest, even though urea water remains in the tank 210. It is possible to prevent the remaining amount from being calculated with reference to the level sensor value L in the state. On the other hand, even if the amount of urea water stored in the tank 210 is large and the vehicle is tilted, when the urea water is present at a position where it touches the level sensor 250, An opportunity to calculate the remaining amount with reference to the level sensor value L can be secured.

  Although the remaining amount of urea water stored in the tank 210 is detected, the remaining amount of other additives may be detected.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Cylinder head, 3 ... Intake passage, 4a-4d ... Fuel injection valve, 5 ... Fuel addition valve, 6a-6d ... Exhaust port, 7 ... Intake manifold, 8 ... Exhaust manifold, 9 ... Common rail, DESCRIPTION OF SYMBOLS 10 ... Supply pump, 11 ... Turbocharger, 12 ... Alarm, 13 ... EGR passage, 14 ... EGR cooler, 15 ... EGR valve, 16 ... Intake throttle valve, 17 ... Actuator, 18 ... Intercooler, 19 ... Air flow meter, DESCRIPTION OF SYMBOLS 20 ... Throttle valve opening sensor, 21 ... Engine rotational speed sensor, 22 ... Accelerator operation amount sensor, 23 ... Outside temperature sensor, 24 ... Vehicle speed sensor, 25a ... Acceleration sensor, 25b ... Acceleration sensor, 26 ... Exhaust passage, 27 ... Fuel supply pipe, 30 ... first purification member, 31 ... oxidation catalyst, 32 ... filter, 40 ... second purification member, 41 ... NOx purification Catalyst (selective reduction type NOx catalyst: SCR catalyst), 50 ... third purification member, 51 ... ammonia oxidation catalyst, 60 ... dispersion plate, 80 ... control device, 100 ... first exhaust temperature sensor, 110 ... differential pressure sensor, 120 2nd exhaust temperature sensor, 130 ... 1st NOx sensor, 140 ... 2nd NOx sensor, 200 ... Urea water supply mechanism, 210 ... Tank, 220 ... Pump, 230 ... Urea addition valve, 240 ... Supply passage, 250 ... Level sensor, 251 ... Float.

Claims (5)

A level sensor that is provided in a tank that stores liquid additive and detects a liquid level indicating the height of the liquid level of the additive;
An acceleration sensor;
An additive remaining amount calculating device for an in-vehicle internal combustion engine comprising: a calculation unit that executes a calculation process for calculating the remaining amount of the additive with reference to a liquid level detected by the level sensor;
The calculation unit sets an execution range, which is a range of acceleration for executing the calculation process, according to a liquid level detected by the level sensor. . When the liquid level detected by the level sensor is greater than or equal to a first level threshold, the calculation unit compares the liquid level with a level less than a second level threshold that is smaller than the first level threshold. The additive remaining amount calculation device for an in-vehicle internal combustion engine according to claim 1, wherein the execution range is set to be wide. A storage unit for storing the remaining amount calculated by the calculation unit;
The calculation unit calculates an addition amount integrated value obtained by integrating the addition amount of the additive from the calculation of the remaining amount of the additive to the next calculation of the remaining amount, and is detected by the acceleration sensor The in-vehicle internal combustion engine according to claim 1 or 2, wherein when the acceleration is out of the execution range, the remaining amount is calculated by subtracting the added amount integrated value from the previously calculated remaining amount stored in the storage unit. Engine additive remaining amount calculation device. The calculation unit sets, as the execution range, an acceleration range in which a difference between a remaining amount calculated through the calculation process and an actual additive remaining amount falls within a certain range. The additive remaining amount calculation device for an on-vehicle internal combustion engine according to claim 1. The calculation unit sets, as the execution range, a first execution range for vehicle longitudinal acceleration and a second execution range for vehicle lateral acceleration,
When the vehicle longitudinal acceleration detected by the acceleration sensor is within the first execution range, and the vehicle lateral acceleration detected by the acceleration sensor is within the second execution range, The additive remaining amount calculation device for an on-vehicle internal combustion engine according to any one of claims 1 to 4, wherein calculation processing is executed.