JP2018025179A - Vehicular cooling system and control method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular cooling system capable of shortening warming-up time while using a heater during warming-up and a control method for the vehicular cooling system.SOLUTION: A water pump 31, a water jacket 32, a radiator 33 and a heater core 34 form a radiator flow passage 35, a heater flow passage 36 and a bypass passage 38. A vehicular cooling system includes a flow control section 40, a rotational speed sensor 41, a temperature sensor 42 and a control device 43. When a temperature Tx of cooling water W1 is below a threshold value Ta, the flow control section 40 is controlled by the control device 43 so that a heater flow rate Qy of the cooling water W1 flowing in the heater core 34 is set to a limit flow rate Qa or lower and so that a jacket flow rate Qx of cooling water W1 flowing in the water jacket 32 is set to the heater flow rate Qy or lower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling system for a vehicle and a control method thereof, and more particularly to a cooling system for a vehicle that shortens a warm-up time and a control method thereof.

  As a cooling system for vehicles, when the engine speed is below a predetermined speed and the temperature of the cooling water is below a predetermined temperature, the electronic control valve is closed and the engine speed exceeds the predetermined speed. In some cases, an electronic control valve is opened (for example, see Patent Document 1). This cooling system avoids an increase in the pressure of the cooling water accompanying an increase in the engine speed by opening and closing the electronic control valve based on the engine speed so that the water pressure of the cooling water does not exceed the threshold value. ing.

JP 2013-234605 A

  By the way, the heater for vehicles uses the cooling water as a heat source. The heater cools the cooling water by heat exchange with the heater core, and blows hot air generated by the heat exchange to various parts of the vehicle with a fan.

  However, in the above apparatus, the electronic control valve is closed when the engine speed is equal to or lower than the predetermined speed and the coolant temperature is equal to or lower than the predetermined temperature. Therefore, when such control is performed, there is a problem that the cooling water does not flow to the heater core and the heater becomes ineffective.

  The present invention has been made in view of the above, and an object of the present invention is to provide a vehicle cooling system capable of shortening the warm-up time while flowing cooling water through the heater core during warm-up, and a control method thereof. Is to provide.

The vehicle cooling system of the present invention that achieves the above object includes a water pump driven by rotational power output from an engine, a water jacket formed inside the engine, and cooling water flowing through the water jacket. A radiator passage and a heater core, the water pump, the water jacket, and a radiator flow path in which the radiator is annularly connected with respect to the flow of cooling water by piping, the water pump, the water jacket, and the A heater flow path in which the heater core is annularly connected with respect to the flow of the cooling water, and a bypass path that is provided in the radiator flow path and branches from the upstream side of the radiator with respect to the flow of the cooling water and merges on the downstream side. In the formed vehicle cooling system, the radiator A flow rate adjusting unit for adjusting the flow rate of the cooling water flowing through each of the heater core, the heater core, and the bypass path, a temperature acquisition device for acquiring the temperature of the cooling water after passing through the water jacket, and a signal line for each of them. And when the temperature of the cooling water acquired by the temperature acquisition device is lower than a preset threshold, the control device adjusts the flow rate adjustment unit, and The heater flow rate for cooling water flowing through the heater core is set to a preset limit flow rate, and the jacket flow rate for cooling water flowing through the water jacket is set to be equal to or less than the heater flow rate.

  In the vehicle cooling system control method of the present invention that achieves the above object, the water pump is driven by the rotational power output from the engine, and the cooling water discharged from the water pump is fed into the engine. For a vehicle that maintains the temperature of the cooling water that has passed through the water jacket within a predetermined range by flowing through the formed water jacket and then passing through a radiator or bypassing the radiator and passing through a heater core. In the cooling system control method, the temperature of the cooling water after passing through the water jacket is acquired, and when the acquired temperature falls below a preset threshold, the heater flow rate for the cooling water flowing through the heater core is preset. And a jacket of cooling water flowing through the water jacket. A method characterized in that, characterized in that the use flow rate to the heater flow below.

  According to the present invention, when the temperature of the cooling water is lower than the threshold value, the jacket flow rate is limited in accordance with the limited flow rate for the heater. Therefore, when the engine is warmed up, The flow rate of the cooling water in the water jacket can be reduced by limiting the flow rate of the cooling water flowing through the water jacket. Thereby, it becomes advantageous for the temperature rise of the early cooling water in a water jacket, and warming-up time can be shortened. Along with this, the time for which the heater can be used can be shortened.

It is a block diagram which illustrates the time of warming-up of 1st embodiment of the cooling system for vehicles of this invention. It is a block diagram which illustrates other than the time of warming-up of 1st embodiment of the cooling system for vehicles of this invention. FIG. 2 is a perspective view illustrating the rotary valve of FIG. 1. It is explanatory drawing which developed each opening part of FIG. 3 in the circumferential direction, and arranged based on the opening degree. FIG. 2 is a relationship diagram illustrating each opening area based on the opening degree of the rotary valve of FIG. 1. It is a flowchart which illustrates the control method of the cooling system for vehicles of this invention. FIG. 5 is a relationship diagram illustrating the relationship between the engine speed and the opening of the rotary valve when the temperature is lower than a threshold value. FIG. 6 is a relationship diagram illustrating the relationship between the engine rotation speed and the heater flow rate when the temperature falls below a threshold value. It is a relationship diagram which illustrated the relationship between temperature and the opening degree of a rotary valve | bulb when temperature is more than a threshold value. It is explanatory drawing which illustrates the state of the heat transfer in the water jacket of FIG. It is a block diagram which illustrates the time of warming-up of 2nd embodiment of the cooling system for vehicles of this invention. FIG. 6 is a relationship diagram illustrating the relationship between engine load and rotation speed and heater flow rate.

  Embodiments of the present invention will be described below with reference to the drawings. In the figure, W1 is the cooling water, A1 is the intake air, G1 is the exhaust gas, and G2 is the EGR gas.

  As illustrated in FIGS. 1 to 4, the vehicle cooling system 30 of the first embodiment is a system that cools the engine 10.

As illustrated in FIGS. 1 and 2, the engine 10 is a vehicle diesel engine or gasoline engine. In the engine 10, the intake air A <b> 1 sucked into the intake passage 11 is compressed by the compressor 13 of the turbocharger 12 and becomes high temperature, and is cooled by the intercooler 14. Thereafter, the intake air A <b> 1 is supplied to the cylinder 16 through the intake manifold 15.

  The intake air A1 supplied to the cylinder 16 is mixed with fuel injected from an injector (not shown) and burned to generate heat energy, and then becomes exhaust gas G1. Further, the heat energy generated at this time rotates the crankshaft 17, and the rotational power is transmitted to the drive wheels.

  The exhaust gas G1 is exhausted to the exhaust passage 19 via the exhaust manifold 18, and after being purified by an exhaust gas purification device (not shown) after driving the turbine 20 of the turbocharger 12, it is discharged into the atmosphere. Further, a part of the exhaust gas G1 is diverted to the EGR passage 21 branched from the exhaust passage 19 and cooled by the EGR cooler 22, and then the flow rate is adjusted by the EGR valve 23 and supplied to the intake passage 11.

  The cooling system 30 includes a water pump 31, a water jacket 32, a radiator 33, and a heater core 34, and a radiator flow path 35, a heater flow path 36, an intake cooling flow path 37, and a bypass path 38 are formed.

  The water pump 31 is connected to the crankshaft 17 via a power transmission mechanism 24 such as an endless belt or chain, and is driven by rotational power output from the engine 10.

  The water jacket 32 is formed inside the engine 10 so as to surround the cylinder 16 and an exhaust port (not shown).

  The radiator 33 is disposed on the front side of the vehicle, and a cooling fan 25 that is connected to and driven by the crankshaft 17 is disposed behind the radiator 33. The radiator 33 cools the cooling water W <b> 1 passing through the inside by using the vehicle speed wind and the cooling air from the subsequent cooling fan 25.

  The heater core 34 is arranged inside a dashboard (not shown) and constitutes a part of the heater 26, and an electric fan 27 is arranged in front of the heater core 34. In the heater 26, the heater core 34 cools the cooling water W <b> 1 passing through the inside using the wind generated by the electric fan 27, while the warm air warmed by the heat exchange of the heater core 34 is transmitted to various places in the vehicle by the electric fan 27. I am blowing.

  In the radiator flow path 35, the water pump 31, the water jacket 32, and the radiator 33 are annularly connected with respect to the flow of the cooling water W <b> 1 by piping.

  The bypass path 38 is provided in the radiator flow path 35. The bypass path 38 crosses the radiator flow path 35 so as to bypass the radiator 33, and is branched downstream from the branch point P1 disposed upstream of the radiator 33 with respect to the flow of the cooling water W1. It merges at the merge point P2.

  In the heater flow path 36, the water pump 31, the water jacket 32, and the heater core 34 are connected in an annular shape with respect to the flow of the cooling water W1. The heater flow path 36 shares the flow path from the junction P2 to the branch point P1 with the radiator flow path 35 with respect to the flow of the cooling water W1.

  In the intake cooling passage 37, the water pump 31, the intercooler 14, and the radiator 33 are connected in an annular shape with respect to the flow of the cooling water W1. The intake air cooling flow path 37 extends from a branch point P3 disposed between the water pump 31 and the water jacket 32 to a junction P4 disposed between the water jacket 32 and the radiator 33 with respect to the flow of the cooling water W1. Are shared with the radiator channel 35.

  The cooling system 30 includes a flow rate adjusting unit 40, a rotation speed sensor 41 as a flow rate acquisition device, a temperature sensor 42 as a temperature acquisition device, and a control device 43.

  The flow rate adjusting unit 40 is disposed at a branch point P1 where the cooling water W1 after passing through the water jacket 32 branches into the radiator flow path 35, the heater flow path 36, and the bypass path 38. The flow rate adjustment unit 40 includes an electric motor 44 and a rotary valve 45. The flow rate adjusting unit 40 adjusts the flow rate of the cooling water W <b> 1 flowing through each of the radiator 33, the heater core 34, and the bypass path 38 by adjusting the opening Ax of the rotary valve 45 by the electric motor 44.

  The rotational speed sensor 41 operates as a flow rate acquisition device, and is a sensor that acquires the rotational speed Nx of the crankshaft 17 of the engine 10. The discharge flow rate of the cooling water W1 discharged from the water pump 31 driven by the rotational power of the engine 10 is proportional to the rotational speed Nx of the engine 10. In this embodiment, the discharge flow rate is indirectly acquired from the rotation speed Nx using the relationship between the discharge flow rate and the rotation speed Nx.

  The temperature sensor 42 operates as a temperature acquisition device, and is a sensor that acquires the temperature Tx of the cooling water W1 after passing through the water jacket 32. The temperature sensor 42 is preferably arranged upstream of the radiator 33 and the heater core 34 with respect to the flow of the cooling water W1. In this embodiment, the temperature sensor 42 is interposed in the flow path from the outlet of the water jacket 32 to the branch point P1. doing.

  The control device 43 includes a CPU that performs various types of information processing, an internal storage device that can read and write programs and information processing results used to perform the various types of information processing, and various interfaces. The control device 43 is connected to the flow rate adjusting unit 40, the rotation speed sensor 41, and the temperature sensor 42 via a signal line (indicated by a one-dot chain line).

  When the temperature Tx of the cooling water W1 is lower than the threshold Ta, the control device 43 adjusts the opening Ax of the flow rate adjusting unit 40 so that the heater flow rate Qy of the cooling water W1 flowing through the heater core 34 becomes the limited flow rate Qa. Has functional elements. Further, the control device 43 has a functional element that makes the jacket flow rate Qx of the cooling water W1 flowing through the water jacket 32 equal to or less than the heater flow rate Qy. In addition, when the temperature Tx of the cooling water W1 is equal to or higher than the threshold Ta, the control device 43 adjusts the opening Ax of the flow rate adjustment unit 40 based on the temperature Tx, and sets the temperature Tx in advance. Have functional elements to maintain. In this embodiment, these functional elements are stored as programs in the internal storage device of the control device 43, but these functional elements may be configured by individual hardware. In addition, the control device 43 may include a functional element that controls various devices such as an injector of the engine 10.

  The threshold Ta is set in advance to a temperature at which it can be determined whether or not the engine 10 needs to be warmed up through experiments and tests. The threshold Ta may be corrected by the outside air temperature.

As illustrated in FIGS. 3 and 4, the rotary valve 45 includes a casing 46 and a rotor 47. The rotor 47 has three openings 48 a, 48 b, 48 c (formed on the back side in the drawing). Each of the opening portions 48c is omitted). In the drawing, x is the axial direction of the rotor 47, and y is the circumferential direction of the rotor 47.

  As illustrated in FIG. 3, the casing 46 is formed in a cylindrical shape with both ends opened, one end is connected to the flow path of the cooling water W <b> 1, and the other end is closed by the rotor 47. A radiator flow path 35, a heater flow path 36, and a bypass path 38 are connected to the outer peripheral surface of the casing 46.

  The rotor 47 is formed in a low and low cylindrical shape, and has an opening at one end communicating with the flow path of the cooling water W1 and a rotating shaft 49 at the bottom of the other end. Is directly connected to the electric motor 44. On the outer peripheral surface of the rotor 47, a radiator opening 48a, a heater opening 48b, and a bypass opening 48c are formed.

  As illustrated in FIG. 4, the outer peripheral surface of the rotor 47 is divided into a region I and a region II in the circumferential direction y. The opening Ax of the flow rate adjusting unit 40 in the figure is set from 0% to 100%, and the rotation angle of the rotor 47 is the initial position (zero degree), and each of the openings 48a, 48b, 48c is closed. The state in which the radiator is open is 0%, only the radiator opening 48a is fully open, and the other is closed in 100%.

  The region I is a region where the opening degree Ax of the flow rate adjusting unit 40 is adjusted based on the rotational speed Nx of the engine 10 when the engine 10 is warmed up, that is, when the temperature Tx is lower than the threshold value Ta. The region II is a region in which the opening degree Ax of the flow rate adjusting unit 40 is adjusted based on the temperature Tx when the temperature Tx is equal to or higher than the threshold value Ta. Aa is an opening that becomes a boundary between the region I and the region II.

  The opening shape of the heater opening 48b in the region I is set based on the discharge flow rate of the water pump 31, that is, the rotational speed Nx of the engine 10 in this embodiment. Each of the opening shapes of the openings 48a, 48b, and 48c in the region II is set based on the temperature Tx of the cooling water W1.

  The radiator opening 48a is a long hole arranged in the region II and extending in the circumferential direction y. The opening 48a for the radiator has an opening width in the axial direction x that increases from a midway position in the region II toward the opening 100%.

  The heater opening 48b is a long hole extending in the circumferential direction y across both the region I and the region II. The opening 48b for the heater has an opening width in the axial direction x that decreases from the opening degree 0% side toward the area II, and once expands from the boundary between the area I and the area II toward the opening degree 100% side. The diameter is reduced after the diameter.

  The bypass opening 48c is a long hole arranged in the region II and extending in the circumferential direction y. The opening 48c for bypass is reduced in diameter after the opening width in the axial direction x is once increased from the boundary between the region I and the region II toward the opening degree 100%.

  In the rotary valve 45, when the rotor 47 rotates inside the casing 46, the openings 48a, 48b, 48c move in the circumferential direction y. As a result, the opening areas Sa, Sb, and Sc communicating with the radiator flow path 35, the heater flow path 36, and the bypass path 38 change. In the figure, hatched portions indicate the opening areas Sa, Sb, and Sc.

As illustrated in FIG. 5, in the region I, the opening areas Sa and Sc in the radiator opening 48 a and the bypass opening 48 c are zero, and the opening Ax in the heater opening 48 b is zero. Except in the case of%, it becomes narrower as the opening degree Ax becomes larger.

  The opening area Sb in the region I is set so that the heater flow rate Qy becomes a constant limit flow rate Qa, except immediately after the engine 10 is started. This limited flow rate Qa is a minimum flow rate necessary for maintaining the heater performance of the heater 26, and is set based on the temperature sensitive characteristics such as the volume of the heater core 34 and the efficiency of heat exchange in the heater core 34. . The limited flow rate Qa is a control target value and is not completely constant, and the actual heater flow rate Qy may have a certain amount of fluctuation.

  From the above, in the region I, the flow of the cooling water W1 is stopped with respect to the radiator 33 and the bypass passage 38, and a certain amount of the cooling water W1 with the limited flow rate Qa flows to the heater core 34. It will be in a state. The water jacket 32 is in a state in which the cooling water W1 having a flow rate equal to or less than the limit flow rate Qa obtained by subtracting the intake air cooling flow rate Qz flowing through the intake air cooling passage 37 from the heater flow rate Qy.

  In the region II, the opening area Sa of the radiator opening 48a increases as the opening degree Ax increases from the midway position. The opening area Sb in the heater opening 48b increases once and then gradually decreases as the opening Ax increases. The opening area Sc in the bypass opening 48c becomes narrower after becoming wider as the opening degree Ax increases to the midway position, and finally becomes zero at the midway position of the region II.

  As illustrated in FIG. 6, the control method of the cooling system 30 starts after the engine 10 starts and ends when the engine 10 stops.

  When started, the temperature sensor 42 acquires the temperature Tx of the cooling water W1 after passing through the water jacket 32 (S10). Next, it is determined whether or not the temperature Tx acquired by the control device 43 is lower than the threshold value Ta (S20).

  When it is determined that the temperature Tx is lower than the threshold Ta, that is, the engine 10 needs to be warmed up, the rotational speed sensor 41 acquires the rotational speed Nx of the engine 10 (S30). Next, the control device 43 adjusts the opening Ax within the range of the region I of the rotor 47 based on the acquired rotation speed Nx (S40).

  As illustrated in FIG. 7, in this step, the control device 43 adjusts the opening degree Ax with reference to a speed control map in which the opening degree Ax of the rotor 47 corresponding to the rotational speed Nx of the engine 10 is set. To do. The speed control map is created in advance by experiments and tests and is stored in the control device 43.

  The opening degree Ax of the rotor 47 is proportional to the rotational speed Nx of the engine 10. As the rotational speed Nx of the engine 10 increases, the discharge flow rate of the cooling water W1 discharged from the water pump 31 increases. On the other hand, when the opening Ax of the rotor 47 is increased as the rotational speed Nx of the engine 10 is increased, the opening area Sb in the heater opening 48b is reduced.

  As illustrated in FIG. 8, when the opening degree Ax is controlled according to the rotational speed Nx of the engine 10 using the speed control map, the heater flow Qy of the cooling water W1 flowing through the heater core 34 is immediately after the engine 10 is started. Except for this, the constant flow rate Qa is kept constant. Then, the jacket flow rate Qx of the cooling water W1 flowing through the water jacket 32 becomes equal to or less than the heater flow rate Qy. The above steps are repeated until the temperature Tx becomes equal to or higher than the threshold value Ta.

  Next, when it is determined that the temperature Tx is equal to or higher than the threshold value Ta, that is, it is not necessary to warm up the engine 10, the control device 43 determines the opening degree Ax within the range II of the rotor 47 based on the acquired temperature Tx. Is adjusted (S50). In this step, the control device 43 adjusts the opening Ax with reference to a map in which the opening Ax of the rotor 47 corresponding to the temperature Tx is set.

  As illustrated in FIG. 9, in this step, the control device 43 adjusts the opening degree Ax with reference to a temperature control map in which the opening degree Ax of the rotor 47 according to the temperature Tx is set. The temperature control map is created in advance by experiments and tests and stored in the control device 43. The temperature control map may be corrected according to the surrounding environment such as outside air temperature.

  The opening Ax of the rotor 47 in the region II is proportional to the temperature Tx. If the opening Ax of the rotor 47 is increased as the temperature Tx of the cooling water W1 is increased, the opening area Sa in the radiator opening 48a is widened, while the opening area Sc in the bypass opening 48c is narrowed. Or it becomes zero. Further, as the temperature Tx of the cooling water W1 becomes lower, when the opening Ax of the rotor 47 is reduced, the opening area Sa in the radiator opening 48a becomes narrower or becomes zero, while the opening in the bypass opening 48c. The opening area Sc is increased. In this way, when the opening degree Ax is controlled according to the temperature Tx using the temperature control map, the flow rate of the cooling water W1 flowing through the radiator 33 and the flow rate of the cooling water W1 flowing through the bypass passage 38 set the temperature Tx as a threshold value. It is adjusted so as to maintain a predetermined range higher than Ta. The above steps are repeated until the engine 10 is stopped.

  By performing the control as described above, the cooling system 30 limits the heater flow rate Qy to a fixed amount of the limited flow rate Qa when the temperature Tx of the cooling water W1 is lower than the threshold value Ta. Further, the jacket flow rate Qx is limited to the limit flow rate Qa or less in accordance with the heater flow rate Qy. Therefore, the flow rate of the cooling water W1 in the water jacket 32 can be reduced by restricting the flow rate of the cooling water W1 flowing through the water jacket 32 while flowing the cooling water W1 through the heater core 34 when the engine 10 is warmed up. Thereby, it becomes advantageous for the temperature rise of the early cooling water in a water jacket, and warming-up time can be shortened. Along with this, the time during which the heater 26 can be used can be shortened.

  As illustrated in FIG. 10, when the jacket flow rate Qx is limited to the limit flow rate Qa or less, the jacket flow rate Qx is smaller than when the cooling water W <b> 1 flows through the radiator 33 or the bypass path 38. Therefore, the flow rate of the cooling water W1 flowing through the water jacket 32 can be reduced. This is advantageous for increasing the amount of heat absorbed from the cylinder 16 or the exhaust port through the member (cylinder block, cylinder head) in the cooling water W1 flowing through the water jacket 32. The amount of heat released to the outside air via the air can be reduced. Along with this, the temperature Tx of the cooling water W1 rises early and the warm-up of the engine 10 is promoted.

  In the cooling system 30, the temperature of the cooling water W <b> 1 flowing through the heater flow path 36 is also raised at an early stage, so that various portions in the vehicle can be warmed up early by the heater 26.

  Further, along with the effect of increasing the temperature of the cooling water W1 flowing through the water jacket 32, the temperature of the oil inside the engine 10, the exhaust gas G1, and the temperature increasing time of the EGR cooler 22 can also be shortened. Thereby, shortening the temperature rise time of the oil temperature is advantageous for reducing friction, and the fuel efficiency during warm-up can be improved. Further, shortening the temperature rise time of the exhaust gas purification device (not shown) is advantageous because the heat emission time from the exhaust gas G1 at the exhaust port is reduced at an early stage to shorten the temperature rise time of the exhaust gas G1. The purification rate of the exhaust gas G1 at the time can be improved. Furthermore, since the temperature of the EGR cooler 22 can be quickly raised to a temperature at which condensed water is not generated by shortening the temperature rise time of the EGR cooler 22, it is advantageous for shortening the time during which the EGR gas G2 can be supplied to the intake air A1. The purification rate of the exhaust gas G1 can be improved.

  Conventionally, a thermostat is used to adjust the flow rate of the cooling water W <b> 1 flowing through the radiator 33 and the bypass passage 38. The thermostat adjusts the flow rate as the internal wax expands or contracts in accordance with the temperature Tx of the cooling water W1. Therefore, there is a possibility that a time lag occurs before the wax changes due to the temperature Tx, and the responsiveness is delayed.

  On the other hand, the rotary valve 45 only needs to adjust the opening degree Ax according to the temperature Tx, and is excellent in responsiveness. In this embodiment, since the rotary valve 45 is used as the flow rate adjusting unit 40, the control for maintaining the temperature Tx of the cooling water W1 within a predetermined temperature range is more linear than the conventional configuration using a thermostat. The flow rate of the cooling water W1 can be adjusted.

  Further, by dividing the outer peripheral surface of the rotor 47 of the rotary valve 45 into the region I and the region II, the control based on the rotational speed Nx of the engine 10 and the control based on the temperature Tx are performed by one valve. be able to. This is advantageous in reducing the number of parts required for the cooling system 30, and is advantageous in simplifying the control, thereby reducing the cost.

  The opening shape of each opening 48a, 48b, 48c of the rotor 47 is not limited to the above, and can be changed as needed. For example, the heater opening 48b includes two elongated holes, which are an elongated hole disposed in the region I and extending in the circumferential direction y, and an elongated hole disposed in the region II and extending in the circumferential direction y. May be. Further, the opening shape in the region II of the heater opening 48b may be a shape in which the opening width in the axial direction x is constant toward the opening degree of 100%. In addition, each of the openings 48a, 48b, and 48c is not limited to the long hole, and may be configured by a plurality of holes.

  As illustrated in FIG. 11, the cooling system 30 for a vehicle according to the second embodiment is different from the first embodiment in a flow rate adjusting unit 40. The flow rate adjustment unit 40 of this embodiment includes a thermostat 50, a bypass valve 51, and a heater valve 52.

  The thermostat 50 is disposed at a branch point of the bypass passage 38, and adjusts the flow rate of the cooling water W1 flowing through the radiator 33 and the bypass passage 38 by expansion or contraction according to the temperature Tx of a thermal expansion body such as wax. . In this embodiment, although arranged at the branch point P1 of the bypass path 38, it may be arranged at the junction P2 of the bypass path 38.

  The bypass valve 51 is a valve that is interposed in the bypass passage 38 and opens or shuts off the bypass valve 51.

  The heater valve 52 is a valve that is interposed in the heater flow path 36, adjusts the opening Ay, and adjusts the heater flow rate Qy of the cooling water W1 flowing through the heater flow path 36.

  When the temperature Tx of the cooling water W1 is lower than the threshold Ta, the cooling system 30 of this embodiment shuts off the radiator passage 35 by the thermostat 50 and shuts off the bypass passage 38 by fully closing the bypass valve 51. By adjusting the opening degree of the heater valve 52 based on the rotational speed Nx, the heater flow rate Qy of the cooling water W1 flowing through the heater core 34 is maintained at a constant limit flow rate Qa.

On the other hand, when the temperature Tx of the cooling water W1 is equal to or higher than the threshold Ta, the thermostat 50 adjusts the flow rates of the cooling water W1 in the radiator passage 35 and the bypass passage 38 by changing the opening degree based on the temperature Tx. Then, by opening the bypass valve 51 fully, the bypass passage 38 is opened, and by adjusting the opening degree of the heater valve 52 based on the rotational speed Nx, the heater flow rate Qy of the cooling water W1 flowing through the heater core 34 is set to a certain amount. Maintain at the limited flow rate Qa.

  By controlling in this way, the jacket flow rate Qx is limited in accordance with the heater flow rate Qy limited to a fixed amount of the limited flow rate Qa. Therefore, the flow rate of the cooling water W1 in the water jacket 32 can be reduced by restricting the flow rate of the cooling water W1 flowing through the water jacket 32 while flowing the cooling water W1 through the heater core 34 when the engine 10 is warmed up. Thereby, it becomes advantageous for the temperature rise of the early cooling water in a water jacket, and warming-up time can be shortened. Along with this, the time during which the heater 26 can be used can be shortened.

  This embodiment can be applied to a conventional configuration in which the flow rate of the cooling water W1 flowing through the radiator 33 and the bypass passage 38 is adjusted by the thermostat 50 by adding the bypass valve 51 and the heater valve 52.

  Further, the flow rate adjusting unit 40 includes a thermostat 50, a bypass valve 51, and a heater valve 52. Thereby, by adjusting the opening degree of the heater valve 52, the temperature Tx of the cooling water W1 becomes equal to or higher than the threshold Ta, and the flow rate of the cooling water W1 in each of the radiator flow path 35 and the bypass path 38 is adjusted by the thermostat 50. Even in such a case, the heater flow rate Qy can be maintained at a constant limit flow rate Qa.

  As illustrated in FIG. 12, the cooling system 30 according to the above-described embodiment may change the heater flow rate Qy when the temperature Tx of the cooling water W <b> 1 is equal to or lower than the threshold Ta in accordance with the load of the engine 10. The load of the engine 10 is obtained from the rotational speed Nx of the engine 10 and the fuel injection amount injected from an injector (not shown).

  The temperature Tx of the cooling water W1 is proportional to the load of the engine 10, and the pressure due to expansion accompanying the temperature rise of the cooling water W1 is also proportional to the load of the engine 10. Therefore, with a predetermined load of the engine 10 as a reference, the heater flow rate Qy is decreased when the load of the engine 10 is lower than the reference, and the heater flow rate Qy is increased when the load of the engine 10 is higher than the reference. Good. Thus, the load applied to the cooling system 30 due to the increase in the pressure of the cooling water W1 can be suppressed by adjusting the heater flow Qy to an amount that has a negative relationship with the load of the engine 10.

  In the embodiment described above, the rotational speed sensor 41 that acquires the rotational speed Nx of the engine 10 is used as the flow rate acquisition device. However, the sensor that acquires the rotational speed of the water pump 31 or the sensor that directly acquires the discharge flow rate. May be used.

  An oil cooler or the like may be added to the above-described embodiment, or a configuration in which the intake air cooling passage 37 is omitted from the above-described embodiment. Further, the heater flow path 36 may be branched at the outlet of the water jacket 32, or the intake cooling flow path 37 may be branched at the outlet of the water pump 31. During warm-up, by providing a flow path (for example, an intake air cooling flow path 37) that branches and merges at the inlet / outlet of the water jacket 32 other than the radiator flow path 35 and the heater flow path 36, the jacket flow rate Qx becomes the heater flow rate. Less than the flow rate Qy. On the other hand, when no other flow path is provided, the jacket flow rate Qx is equal to the heater flow rate Qy.

In the above-described embodiment, the configuration in which the cooling water W1 always flows through the heater core 34 has been described as an example. However, a valve interposed in the heater flow path 36 is provided, and this valve cools down when the heater 26 is used. The water W1 may flow through the heater core 34. However, this valve is preferably controlled so that it is fully open when warmed up.

DESCRIPTION OF SYMBOLS 10 Engine 30 Cooling system 31 Water pump 32 Water jacket 33 Radiator 34 Heater core 35 Radiator flow path 36 Heater flow path 38 Bypass path 40 Flow rate control part 41 Rotation speed sensor 42 Temperature sensor 43 Control device Qx Jacket flow rate Qy Heater flow rate

Claims (6)

A water pump driven by rotational power output from the engine; a water jacket formed inside the engine; and a radiator and a heater core through which the cooling water flowing through the water jacket passes, the water pump, the water A jacket, and a radiator flow path in which the radiator is annularly connected with respect to the flow of the cooling water by piping, and a heater flow path in which the water pump, the water jacket, and the heater core are annularly connected with respect to the flow of the cooling water And a bypass path that is provided in the radiator flow path and is branched from the upstream side of the radiator with respect to the flow of the cooling water and merges on the downstream side,
A flow rate adjusting unit that adjusts the flow rate of the cooling water flowing through each of the radiator, the heater core, and the bypass path, a temperature acquisition device that acquires the temperature of the cooling water after passing through the water jacket, and a signal to each of them. A control device connected via a line,
When the temperature of the cooling water acquired by the temperature acquisition device falls below a preset threshold value, the control device adjusts the flow rate adjusting unit to set a heater flow rate for cooling water flowing through the heater core in advance. A cooling system for a vehicle, characterized in that the flow rate for cooling water flowing through the water jacket is set to be equal to or less than the flow rate for the heater.   The vehicle cooling system according to claim 1, wherein the restricted flow rate is set based on heater performance by the heater core. A flow rate acquisition device that is connected to the control device via a signal line and indirectly or directly acquires the discharge flow rate of cooling water discharged from the water pump;
When the temperature of the cooling water is lower than the threshold value, the control device adjusts the flow rate control unit based on the discharge flow rate acquired by the flow rate acquisition device, thereby reducing the heater flow rate to a fixed amount. The cooling system for vehicles according to claim 1 or 2 constituted so that it may be maintained. The heater flow path shares the flow path from the junction of the bypass path to the branch point in the radiator flow path with the radiator flow path;
The flow rate adjustment unit is arranged at a branch point thereof, and is configured by a rotary valve connected to each of the radiator flow path, the heater flow path, and the bypass path. A cooling system for a vehicle according to item 1.   The flow rate adjusting unit is a thermostat disposed at either the junction or branch point of the bypass path in the radiator flow path, a bypass valve interposed in the bypass path, and a heater valve interposed in the heater flow path The cooling system for vehicles of any one of Claims 1-3 comprised from these. The water pump is driven by the rotational power output from the engine, and after cooling water discharged from the water pump flows through the water jacket formed inside the engine, the radiator is passed through or bypassed. In the method for controlling the cooling system for a vehicle, the temperature of the cooling water that has passed through the water jacket is maintained in a predetermined range by passing through the bypass path and the heater core.
Obtain the temperature of the cooling water after passing through the water jacket,
When the acquired temperature falls below a preset threshold value, the heater flow rate for the cooling water flowing through the heater core is set to a preset limit flow rate, and the jacket flow rate for the cooling water flowing through the water jacket is set to the heater flow rate. A method for controlling a cooling system for a vehicle, comprising:

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