JP2019100298A - Cooling controller - Google Patents

Abstract

To provide a cooling controller capable of appropriately controlling a cooler of an internal combustion engine to suppress an increase of a fuel pressure in the internal combustion engine.SOLUTION: A cooling controller (50) controls a cooler (60) for cooling a direct-injection internal combustion engine (10), which directly injects, into a cylinder, high-pressure fuel stored in a pressure accumulation container (13). The cooling controller comprises: a fuel temperature acquisition unit (51) configured to acquire a temperature of the high-pressure fuel; a temperature information acquisition unit (53) configured to acquire temperature information related to a temperature in an engine room where the internal combustion engine is installed; an estimation unit (55) configured to, based on the temperature of the high-pressure fuel and the temperature information in a stop of the internal combustion engine, estimate a maximum fuel pressure which is a maximum value of a fuel pressure of the high-pressure fuel after the stop of the internal combustion engine; and a control unit (58) configured to, on condition that the maximum fuel pressure exceeds a threshold, operate the cooler.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cooling control device that controls a cooling device that cools a direct injection type internal combustion engine.

  In an internal combustion engine mounted on a vehicle or the like, the internal combustion engine is cooled by an electric fan or the like after the internal combustion engine is stopped. For example, in Patent Document 1, when the engine of the vehicle is stopped, the engine heat release amount and the engine temperature are predicted, the coolant temperature returned from the engine is detected, and the engine temperature and the coolant temperature are set for each. The technology of operating the cooling fan and cooling the engine is described when it is determined that the threshold of the above is exceeded.

Unexamined-Japanese-Patent No. 2006-97648

  In a direct injection type internal combustion engine, if the fuel present in the fuel pump becomes too hot while the internal combustion engine is stopped, bubbles are generated in the fuel and the pressure (fuel pressure) of the fuel rises, and the internal combustion engine is started next time May not be able to supply enough fuel to the In addition, when the fuel pressure increases, the minimum injection amount at the time of fuel ejection increases, which may cause a decrease in combustion efficiency due to the enrichment of the air-fuel ratio and an increase in energy consumption at the time of fuel ejection.

  For example, even if the engine temperature or the fuel temperature (fuel temperature) is low when the vehicle is stopped, the fuel temperature may increase and the fuel pressure may increase thereafter if the temperature in the engine room is high. In such a case, as in the technology of Patent Document 1, when it is determined whether to operate the cooling fan based on the engine water temperature detected at the time of engine stop and the predicted engine temperature, the cooling fan does not operate.

  In view of the above, the present invention provides a cooling control device that can appropriately control a cooling device of an internal combustion engine to suppress an increase in fuel combustion pressure in the internal combustion engine.

  The present invention provides a cooling control device that controls a cooling device that cools a direct injection type internal combustion engine that directly injects high pressure fuel stored in a pressure accumulation container into a cylinder. The cooling control device includes a fuel temperature acquisition unit for acquiring the temperature of the high pressure fuel, a temperature information acquisition unit for acquiring temperature information related to the temperature of the engine chamber in which the internal combustion engine is installed, and the stop time of the internal combustion engine An estimation unit for estimating a maximum fuel pressure which is a maximum value of the fuel pressure of the high pressure fuel after the internal combustion engine is stopped based on the temperature of the high pressure fuel and the temperature information; and a condition that the maximum fuel pressure exceeds a threshold And a control unit for operating the cooling device.

  According to the present invention, the maximum fuel pressure of the high pressure fuel is estimated based on the temperature of the high pressure fuel and the temperature information related to the temperature of the engine chamber in which the internal combustion engine is installed. Then, the cooling device is operated to cool the internal combustion engine on condition that the maximum fuel pressure exceeds the threshold. In order to estimate the maximum fuel pressure of the high pressure fuel by using the temperature of the high pressure fuel and the temperature information of the engine room, not only when the fuel temperature is high at present, but also the temperature of the fuel is low from the temperature information of the engine room The cooling device can also be operated if the fuel temperature can rise. Therefore, the fuel pressure of the high pressure fuel can be reliably prevented from becoming excessively high.

The block diagram of a drive system. The block diagram of a cooling control apparatus. Flow chart of cooling control. 6 is a flowchart of correction value calculation processing.

  FIG. 1 shows a drive system 1 of an internal combustion engine 10 mounted on a vehicle. The drive system 1 controls the drive of a cylinder injection (direct injection) internal combustion engine 10. The drive system 1 includes an internal combustion engine 10, a fuel tank 11, a high pressure pump 12, a delivery pipe 13, an injector 14, a low pressure side pipe 15, a low pressure pump 16, a high pressure side pipe 17, sensors 40 and the like. , And a control device 50, and a cooling device 60. In FIG. 1, a fuel supply system is configured by a fuel tank 11, a high pressure pump 12, a delivery pipe 13, an injector 14, a low pressure side pipe 15, a low pressure pump 16 and a high pressure side pipe 17. The delivery pipe 13 corresponds to a pressure accumulation container, and the injector 14 corresponds to a fuel injection valve. The control device 50 functions as a cooling control device that controls the cooling device 60 and also has a function of controlling the internal combustion engine 10.

  In the present embodiment, the internal combustion engine 10 is a four-cylinder internal combustion engine, and each cylinder of the internal combustion engine 10 is provided with an injector 14 for injecting fuel into each cylinder. In addition, an ignition plug is attached to each cylinder of the cylinder head of the internal combustion engine 10, and the mixture in the cylinder is ignited by spark discharge of the ignition plug.

  The high pressure pump 12 and the fuel tank 11 are connected by a low pressure side pipe 15. A low pressure pump 16 and a low pressure fuel temperature sensor 41 are installed in the low pressure side pipe 15. The low pressure pump 16 sucks the fuel in the fuel tank 11 and discharges it after pressurizing it. The pressure of the fuel discharged by the low pressure pump 16 is regulated by a regulator (not shown) or the like. In addition, the low pressure side pipe 15 is provided with a low pressure fuel temperature sensor 41.

  The high pressure pump 12 pumps the fuel from the low pressure pump 16, further increases the pressure and discharges it. The high pressure pump 12 pressurizes the fuel in the pressure chamber by a plunger and discharges the fuel from the discharge valve to the high pressure side pipe 17. The high pressure pump 12 is provided with a control valve for adjusting the discharge amount from the discharge valve, and the amount of fuel supplied to the delivery pipe 13 is controlled by the control device 50 controlling the opening amount of the control valve. Is adjusted.

  The delivery pipe 13 stores the fuel discharged to the high pressure side pipe 17 by the high pressure pump 12 in a pressurized state. The delivery pipe 13 is provided with a high pressure fuel temperature sensor 42 for detecting the temperature of the fuel in the delivery pipe 13 and a fuel pressure sensor 43 for detecting the pressure. The high pressure fuel temperature sensor 42 is installed at the tip of the delivery pipe 13 (the distal end with respect to the high pressure pump 12 side).

  An injector 14 is in communication with the delivery pipe 13. The high pressure side pipe 17 may be provided with a relief valve for reducing the pressure of the fuel in the delivery pipe 13. The injector 14 directly injects the fuel in the delivery pipe 13 into the cylinder of the internal combustion engine 10. The fuel injection control of the injector 14 and the ignition control of the spark plug are performed by the controller 50.

  The control device 50 is an electronic control unit (ECU) mainly composed of a microcomputer including a known CPU, ROM, RAM and the like, and controls the operation of the internal combustion engine 10 using detection signals of the sensors 40. The control device 50 controls a drive system of the internal combustion engine 10 or the like and also controls a cooling device 60 for cooling the internal combustion engine 10.

  As shown in FIG. 2, as the sensors 40 for outputting a detection signal to the control device 50, in addition to the low pressure fuel temperature sensor 41, the high pressure fuel temperature sensor 42, and the fuel pressure sensor 43 described above, the temperature of engine cooling water is detected. Water temperature sensor 44, oil temperature sensor 45 for detecting the oil temperature of engine oil, outside air temperature sensor 46 for detecting the outside air temperature, exhaust temperature sensor 47 for detecting exhaust temperature, intake air temperature sensor 48 for detecting intake temperature, internal combustion engine The ignition sensor 49 which detects the starting state of 10 is mentioned. Although not illustrated in FIG. 2, the sensors 40 may further include a sensor that detects information on the driving history of the vehicle, the rotational speed of the internal combustion engine 10, and the load, and the like. The control device 50 outputs a signal to the electric pump 61 as the cooling device 60 and the electric fan 62. By operating the electric pump 61, cooling water can be circulated to the internal combustion engine 10 to cool the internal combustion engine 10. The electric fan 62 can be operated by energizing the drive motor to cool the internal combustion engine 10.

  The control device 50 includes a fuel temperature acquisition unit 51, a fuel pressure acquisition unit 52, a temperature information acquisition unit 53, a fuel temperature estimation unit 54, a fuel pressure estimation unit 55, a correction value calculation unit 56, and a determination unit 57. A cooling control unit 58 and a storage unit 59 are provided.

  The fuel temperature acquisition unit 51 acquires the temperature of the fuel detected by the low pressure fuel temperature sensor 41 and the high pressure fuel temperature sensor 42. The fuel pressure acquisition unit 52 acquires the pressure of the fuel detected by the fuel pressure sensor 43.

  The temperature information acquisition unit 53 acquires temperature information related to the temperature in the engine chamber in which the internal combustion engine 10 is installed. The temperature information may be a detected value or an estimated value of the temperature in the engine room, or may be a detected value of a parameter related to the temperature in the engine room (a parameter other than the temperature in the engine room). For example, detection values of the water temperature sensor 44, the oil temperature sensor 45, the outside air temperature sensor 46, the exhaust temperature sensor 47, the intake temperature sensor 48 and the like can be used as the temperature information of the engine room. Furthermore, the temperature information acquisition unit 53 may acquire information related to the operation history of the internal combustion engine 10, for example, the vehicle speed, the rotation speed, the load, and the like from the start to the stop of the internal combustion engine 10.

  The stop of the internal combustion engine 10 can be detected by the ignition sensor 49 which detects the on / off of the ignition switch of the vehicle. When it is detected that the internal combustion engine 10 has stopped, the fuel temperature estimation unit 54 calculates the fuel temperature of the high pressure system (the high pressure side pipe 17 or the delivery pipe 13) while the internal combustion engine 10 is stopping, and its maximum value And estimate the maximum fuel temperature Tp. Further, the fuel pressure estimation unit 55 calculates the fuel pressure of the high pressure system while the internal combustion engine 10 is stopped, and estimates the maximum fuel pressure Pp which is the maximum value thereof.

  The correction value calculation unit 56 calculates the difference between the estimated value and the detected value of the fuel temperature and the fuel pressure of the high pressure system while the internal combustion engine 10 is stopped, and stores it as the leak amount VL. The leak amount VL indicates the amount of fuel leaking in the high pressure system, and is used when the fuel pressure estimation unit 55 estimates the fuel pressure. The determination unit 57 determines the necessity of the cooling control based on the value of the maximum fuel pressure Pp estimated by the fuel pressure estimation unit 55. If the determination unit 57 determines that the cooling control is necessary, the condition for the cooling control may be calculated based on the value of the maximum fuel pressure Pp.

  The cooling control unit 58 controls the cooling device 60 to cool the internal combustion engine 10 when the determination unit 57 determines that the cooling control is necessary. The cooling control unit 58 may set the operating conditions (such as the output and the cooling period) of the cooling device 60 based on the estimated maximum fuel pressure Pp. The storage unit 59 stores the above-mentioned estimated value, detected value, and the like. The cooling control unit 58 may operate the cooling device 60 based on other than the estimated value of the maximum fuel pressure Pp. For example, the cooling control unit 58 may immediately operate the cooling device 60 only on the condition that the internal combustion engine 10 is stopped, or the cooling device on the condition that the internal combustion engine 10 is high temperature when the internal combustion engine 10 is stopped. You may drive 60. If the cooling device 60 is operated in advance regardless of the maximum fuel pressure Pp, then the output of the cooling device 60 and the operating period may be reset based on the maximum fuel pressure Pp. While it is possible to cool the internal combustion engine 10 immediately after it is stopped, as a result of estimating the maximum fuel pressure Pp, if the cooling is excessive or unnecessary, the operating condition of the cooling device 60 is promptly changed or stopped. Power consumption can be reduced.

The calculation of the fuel temperature of the high pressure system in the fuel temperature estimation unit 54 can be performed, for example, based on the following equation (1) that represents the heat balance of the high pressure pump 12 and the delivery pipe 13. In the following formula (1), Ts: fuel temperature of high pressure system at the time of stop, Tp: maximum fuel temperature of high pressure system after stop, Q1: heat receiving amount of high pressure pump 12, Q2: heat release amount of high pressure pump 12, Q3: The amount of heat received by the delivery pipe 13, C: specific heat capacity of fuel, Vh: high-pressure system volume.
C × Vh × (Tp−Ts) = Q1−Q2 + Q3 (1)

Here, as shown in the following equation (2), the heat reception amount Q3 in the delivery pipe 13 is proportional to the temperature gradient between the temperature Te in the engine chamber and the fuel temperature T2 at the outlet of the high pressure pump 12. Further, the heat quantity (Q2-Q1) is proportional to the difference between the outlet fuel temperature T2 of the high-pressure pump 12 and the inlet fuel temperature T1, as shown in the following equation (3). H: heat transfer coefficient, S: heat transfer area, Vp: fuel volume in the pump.
Q3 = S × h × (Te−T2) (2)
C × Vp × (T2-T1) = Q1-Q2 (3)

  The maximum fuel temperature Tp can be calculated by using the following formulas (2) and (3) for the above formula (1). As the inlet fuel temperature T1 of the high pressure pump 12, a detection value of the low pressure fuel temperature sensor 41 can be used. As the fuel temperature Ts, a detection value of the high pressure fuel temperature sensor 42 can be used. As the temperature Te of the engine room, detection values of sensors acquired by the temperature information acquisition unit 53 (for example, detection values of the water temperature sensor 44, oil temperature sensor 45, outside air temperature sensor 46, exhaust temperature sensor 47, intake temperature sensor 48, etc. Or the temperature in the engine room estimated based on the operation history of the internal combustion engine 10 or the like. Depending on the position where the high pressure fuel temperature sensor 42 is installed, the detected value of the high pressure fuel temperature sensor 42 may be used as the outlet temperature of the high pressure pump 12 when calculating the heat reception amount Q3 in the delivery pipe 13. In this case, the maximum fuel temperature Tp can be calculated without using the detection value of the low pressure fuel temperature sensor 41.

  As the fuel temperature Ts, a detection value of the high pressure fuel temperature sensor 42 at the time of stop of the internal combustion engine 10 can be used. Further, as the temperature Te, it is possible to use a value obtained based on temperature information such as detected values of the water temperature sensor 44, the oil temperature sensor 45, the outside air temperature sensor 46, the exhaust temperature sensor 47, the intake temperature sensor 48 and the like. Further, an operation history of the internal combustion engine 10 or the like may be used to estimate the temperature Te. More specifically, the vehicle speed, rotational speed, load and the like from the start to the stop of the internal combustion engine 10 may be stored by the storage unit 59 and read and used when estimating the fuel temperature and the like.

The calculation of the fuel pressure of the high pressure system in the fuel pressure estimation unit 55 can be performed, for example, based on the following formulas (4) and (5). In the following formulas (4) and (5), Ps: fuel pressure at the inlet of the high pressure pump 12 at the time of stop, Pp: maximum fuel pressure at the inlet of the high pressure pump 12 after stop, Vh: volume of high pressure system, VL: leak amount, a: volumetric expansion coefficient of fuel b: volumetric elastic coefficient of fuel
Vc = a * (Tp-Ts) * Vh-VL (4)
Pp = Ps + b × Vc / Vh (5)

  The calculation of the leak amount VL is performed, for example, based on the measured value of the fuel temperature or the fuel pressure when the cooling control is not performed, as described below.

When cooling control is not performed, the fuel temperature of the high pressure system at the time of stop: Tso, and the maximum fuel temperature of the high pressure system after stop: Tpo are measured, and by using the detection values Tso and Tpo in the following equation (6), An estimated value Vco of the volume increase can be calculated. In addition, VL1 has shown the leak amount before the update memorize | stored in the memory | storage means of the control apparatus 50. FIG.
Vco = a × (Tpo−Tso) × Vh−VL1 (6)

Moreover, when cooling control is not performed, the fuel pressure of the high pressure system at the time of stop: Pso, and the maximum fuel pressure of the high pressure system after stop: Ppo are measured, and the detection values Pso and Ppo are used in the following formula (7). The calculated value Vro of the volume increase can be calculated.
Vro = (Ppo−Pso) × Vh / b (7)

The correction value VLd of the leak amount VL can be calculated by the following equation (8). The leak amount VL2 after update can be calculated based on the following equation (9) using the correction value VLd.
VLd = Vco-Vro (8)
VL2 = VL1-VLd (9)

  The cooling control unit 58 may operate the cooling device 60 regardless of the maximum fuel pressure after the internal combustion engine 10 is stopped. For example, after the internal combustion engine 10 is stopped, an operation request to operate the cooling device 60 may occur based on the temperature of the cooling water, and in such a case, the cooling control unit 58 reduces the temperature of the cooling water to a predetermined value. Control is performed to operate the cooling device 60 in the period until the predetermined time or the predetermined time elapses.

  When the cooling device 60 is operated in advance after the internal combustion engine 10 is stopped, the fuel pressure estimating unit 55 determines the maximum fuel pressure based on the temperature and temperature information of the high pressure fuel when the operation of the cooling device 60 is stopped. The determination unit 57 determines whether to operate the cooling device 60 based on the maximum fuel pressure. If the determination unit 57 determines that the cooling device 60 is to be operated, the cooling control unit 58 resumes the operation of the cooling device 60.

  When the cooling device 60 is operated in advance, it is conceivable that the temperature, the water temperature, the oil temperature and the like (temperature information) of the high pressure fuel decrease during the preliminary operation. In this case, the maximum fuel pressure may be estimated in consideration of changes in the temperature of the high-pressure fuel, changes in the water temperature, oil temperature, and the like during the preliminary operation. For example, the maximum fuel pressure may be estimated to be a smaller value as the decrease amount or decrease rate (slope) of the fuel temperature during the preliminary operation of the cooling device 60 is larger.

  Alternatively, as apparent from the equation (2), the larger the temperature difference between the temperature Te in the engine chamber and the outlet fuel temperature T2 of the high-pressure pump 12, the larger the amount of heat reception Q3. It may be determined whether traveling is performed such that the temperature difference between the indoor temperature Te and the outlet fuel temperature T2 of the high pressure pump 12 is large, and the necessity of the operation of the cooling device 60 may be determined. Specifically, the temperature information acquisition unit 53 is configured to be able to acquire information (vehicle speed, rotational speed, load, etc.) regarding the operation history of the internal combustion engine 10, and the internal combustion engine 10 is stopped based on the acquired operation history information. It may be determined in advance whether traveling has been performed such that the temperature difference between the temperature Te in the engine room and the outlet fuel temperature T2 of the high-pressure pump 12 tends to be large.

  For example, when high load traveling is performed before the internal combustion engine 10 stops, the temperature of the internal combustion engine 10 tends to be high. On the other hand, the fuel consumption rate is high during high load traveling, and the fuel pressure-fed from the high pressure pump 12 is consumed without staying for a long period of time, so the high pressure pump is used during high load traveling. The outlet fuel temperature T2 at 12 hardly rises, and the temperature difference between the temperature Te in the engine chamber and the outlet fuel temperature T2 of the high-pressure pump 12 tends to be large immediately after the internal combustion engine 10 is stopped. Therefore, it is better to operate the cooling device 60 after the internal combustion engine 10 is stopped.

  Similarly, even if the temperature Te in the engine room is high, if the fuel temperature (for example, the fuel temperature T2) is also high, the received heat amount Q3 decreases and the fuel pressure hardly increases. For example, when light load operation with a low fuel consumption speed such as idling continues after high load traveling, the fuel temperature rises during light load operation, and when the internal combustion engine 10 is stopped, the temperature difference with the temperature Te in the engine chamber Becomes smaller. In such a case, it is better not to operate the cooling device 60.

  The flowchart of the cooling control which the control apparatus 50 performs in FIG. 3 is shown. First, in step S101, it is determined based on the input from the ignition sensor 49 whether or not the internal combustion engine 10 has stopped. When the internal combustion engine 10 is stopped (that is, when the ignition switch is in the OFF state), the process proceeds to step S102. Next, in step S102, it is determined whether the cooling device 60 has stopped. When the cooling device 60 is stopped, the process proceeds to step S103, and the fuel temperature Ts and the fuel pressure Ps at the time of stopping the internal combustion engine 10 are acquired and stored.

  Next, in step S104, the engine room temperature information is acquired. The temperature information is information related to the temperature of the engine room, and specifically, for measuring the water temperature, oil temperature, exhaust system temperature, intake system temperature, outside temperature, fuel temperature of low pressure system or high pressure system, etc. Acquire the detection value of the temperature sensor. In addition to the above, information on the operation history of the internal combustion engine 10 (vehicle speed, rotational speed, load, etc.) may be acquired as the temperature information.

  Next, in step S105, the maximum fuel temperature Tp is estimated based on the above formulas (1) to (3). Next, at step S106, the maximum fuel pressure Pp is estimated based on the above equations (4) and (5).

  Next, in step S107, it is determined whether the maximum fuel pressure Pp is higher than the threshold value X. If the maximum fuel pressure Pp exceeds the threshold value X, the process proceeds to step S108, and a process related to cooling control is performed. If the maximum fuel pressure Pp is equal to or less than the threshold value X, the process proceeds to step S112, and the correction value calculation process (step S113) for the leak amount VL is performed without performing the cooling process.

  Next, in step S108, the cooling condition is calculated based on the maximum fuel pressure Pp. Specifically, the cooling conditions such as the output of the electric pump 61 and the electric fan 62 as the cooling device 60 and the cooling period are calculated. Next, in step S109, the cooling device 60 is controlled based on the calculated cooling condition to start cooling. Thereafter, the internal combustion engine 10 is cooled by the cooling device 60 until it is determined in step S110 that the cooling period has ended, and the cooling is ended in step S111.

  FIG. 4 shows a flowchart of the correction value calculation process of the leak amount VL, which is performed in step S113. First, in step S201, the fuel temperature detected by the high pressure fuel temperature sensor 42 and the fuel pressure detected by the fuel pressure sensor 43 are acquired. The fuel temperature and the fuel pressure are periodically acquired and stored in the storage means. Next, in step S202, the maximum fuel temperature Tpo and the maximum fuel pressure Ppo are stored from the acquired detection values of the fuel temperature and the fuel pressure.

  In step S203, the stored leak amount VL1 is read. In step S204, an estimated value Vco of the volume increase amount is calculated based on the above equation (6). The stop fuel temperature Tso uses the detection value of the fuel temperature at the stop acquired in step S102, and the maximum fuel temperature Tpo uses the highest value of the detection value of the fuel temperature acquired in step S202. .

  Next, in step S205, the calculated value Vro of the volume increase is calculated based on the above equation (7). The stop fuel pressure Pso uses the detection value of the fuel pressure at the time of stop acquired in step S102, and the maximum fuel pressure Ppo uses the highest value of the detection value of the fuel pressure acquired in step S202.

  Next, in step S206, the correction value VLd of the leak amount VL is calculated based on the equation (8). Next, in step S207, the leak amount VL1 stored in the storage unit is corrected using the correction value VLd calculated in the above equation (9), updated as the leak amount VL2, and stored in the storage unit.

  According to the embodiment described above, the following effects can be obtained.

  Based on the fuel temperature of the high pressure fuel acquired by the fuel temperature acquisition unit 51 and the temperature information acquired by the temperature information acquisition unit 53, the fuel pressure estimation unit 55 determines the maximum value of the fuel pressure of the high pressure system after the internal combustion engine 10 is stopped. The maximum fuel pressure Pp is estimated. Then, the cooling control unit 58 operates the cooling device 60 when the maximum fuel pressure Pp exceeds the threshold value X. In order to estimate the maximum fuel pressure Pp using the fuel temperature of the high pressure system and the temperature information in the engine room, not only when the fuel temperature is high at the present time, but although the fuel temperature is low at present, the temperature environment of the engine room The operation of the cooling device 60 can also be started when the fuel temperature can be increased. Therefore, the high pressure fuel can be cooled quickly, and the fuel pressure can be reliably prevented from exceeding the maximum fuel pressure Pp.

  The control device 50 further includes a fuel pressure acquisition unit 52 for acquiring the fuel pressure, and the fuel pressure estimation unit 55 estimates the maximum fuel pressure Pp based on the temperature and fuel pressure of the high pressure fuel and the temperature information. Since the maximum fuel pressure Pp is estimated using the detection values of the fuel temperature and the fuel pressure for the state of the high pressure fuel, the maximum fuel pressure Pp can be estimated more accurately.

  The control device 50 includes a correction value calculation unit 56 that calculates the leak amount VL of the high pressure system. When the cooling control unit 58 does not operate the cooling device 60, the correction value calculation unit 56 detects a detection value of high pressure fuel acquired by the fuel temperature acquisition unit 51 and a detection value of fuel pressure of high pressure fuel acquired by the fuel pressure acquisition unit 52. And the leak amount VL is calculated as a correction value for correcting the maximum fuel pressure Pp. In the high pressure system, the estimated value of the maximum fuel pressure Pp may deviate from the actual value when a fuel leak occurs. However, the amount of leak is calculated by the correction value calculation unit 56 and appropriately updated. The maximum fuel pressure Pp can be appropriately corrected in consideration.

  The control device 50 may control the output or the operating period of the cooling device 60 based on the maximum fuel pressure Pp estimated by the fuel pressure estimation unit 55. The power consumption of the cooling device 60 can be appropriately controlled.

  When the temperature of the internal combustion engine 10 is high when the internal combustion engine 10 is stopped, the control device 50 may operate the cooling device 60 immediately when the internal combustion engine 10 is stopped regardless of the maximum fuel pressure. As described above, when the cooling device 60 is operated for a predetermined period after the internal combustion engine 10 is stopped and then stopped, the fuel pressure estimating unit 55 determines the temperature and temperature information of the high pressure fuel during operation of the cooling device 60 The maximum fuel pressure Pp may be estimated based on The maximum fuel pressure Pp can be estimated in consideration of the influence of the cooling control performed previously.

  In addition, the temperature information acquisition unit 53 may be configured to be capable of acquiring information (vehicle speed, rotational speed, load, and the like) regarding the operation history of the internal combustion engine 10. Furthermore, based on the acquired operation history information, the determination unit 57 performs traveling in which the temperature difference between the temperature Te in the engine chamber and the outlet fuel temperature T2 of the high-pressure pump 12 tends to be large before the internal combustion engine 10 stops. It may be determined whether or not the operation of the cooling device 60 is necessary. By referring to the operation history of the internal combustion engine 10 as well as the fuel temperature and fuel pressure when the internal combustion engine 10 is stopped, changes in the fuel temperature and fuel pressure after the internal combustion engine 10 is stopped are estimated more accurately It is possible to more accurately determine the necessity of the operation of 60.

  Further, based on the detection values of the fuel temperature acquisition unit 51 and the fuel pressure acquisition unit 52, the control device 50 stores the relationship between the fuel temperature and the fuel pressure as a mathematical expression or a table, and relates the stored fuel temperature to the fuel pressure. Based on the calculated maximum fuel temperature Tp, the maximum fuel pressure Pp may be calculated. In addition, the relationship between the fuel temperature and the fuel pressure may be derived using the detection values of the fuel temperature acquisition unit 51 and the fuel pressure acquisition unit 52 acquired when the cooling device 60 is not operated after the internal combustion engine 10 is stopped. preferable.

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 13 ... Delivery pipe, 50 ... Control apparatus, 51 ... Fuel temperature acquisition part, 53 ... Temperature information acquisition part, 55 ... Fuel pressure estimation part, 58 ... Cooling control part, 60 ... Cooling device

Claims (6)

A cooling control device (50) for controlling a cooling device (60) for cooling a direct injection type internal combustion engine (10) which directly injects high pressure fuel stored in a pressure accumulation container (13) into a cylinder,
A fuel temperature acquisition unit (51) for acquiring the temperature of the high pressure fuel;
A temperature information acquisition unit (53) for acquiring temperature information related to a temperature of an engine chamber in which the internal combustion engine is installed;
An estimation unit (55) for estimating a maximum fuel pressure, which is the maximum value of the fuel pressure of the high pressure fuel after the internal combustion engine is stopped, based on the temperature of the high pressure fuel and the temperature information when the internal combustion engine is stopped;
And a control unit (58) for operating the cooling device on condition that the maximum fuel pressure exceeds a threshold. It further comprises a fuel pressure acquisition unit (52) for acquiring the fuel pressure of the high pressure fuel,
The cooling control device according to claim 1, wherein the estimation unit estimates the maximum fuel pressure based on a temperature and a fuel pressure of the high pressure fuel and the temperature information.   The maximum fuel pressure is corrected based on the temperature of the high pressure fuel acquired by the fuel temperature acquisition unit and the fuel pressure of the high pressure fuel acquired by the fuel pressure acquisition unit when the control unit does not operate the cooling device. The cooling control device according to claim 2, further comprising a correction value calculation unit (56) that calculates a correction value for the image.   The cooling control device according to any one of claims 1 to 3, wherein the control unit controls an output or an operating period of the cooling device based on the maximum fuel pressure estimated by the estimation unit.   The estimation unit determines the temperature and the temperature information of the high-pressure fuel when the operation of the cooling device is stopped when the cooling device is operated in advance regardless of the maximum fuel pressure after the internal combustion engine is stopped. The cooling control device according to any one of claims 1 to 4, wherein the maximum fuel pressure is estimated based on.   The cooling control device according to claim 5, wherein the estimation unit estimates the maximum fuel pressure based on at least one of a change in the temperature of the high pressure fuel and a change in the temperature information during the preliminary operation of the cooling device.

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