JP6152737B2 - Engine cooling system - Google Patents

Description

  The present invention relates to an engine cooling system, and more particularly to an engine cooling system capable of improving engine cooling performance without deteriorating fuel consumption of a large vehicle.

  The engine cooling system mounted on the vehicle dissipates heat from the engine cooling water using the vehicle speed wind from the radiator and the cooling air from the cooling fan. When the load becomes high, it is necessary to increase the cooling air in order to improve the cooling performance.

  However, when the cooling air is increased in this way, in a large vehicle such as a truck, the cooling fan is rotationally driven by an engine located behind, so that the fuel consumption is greatly deteriorated compared to a passenger vehicle using an electric fan. (For example, refer to Patent Document 1).

  Therefore, in large vehicles, it is required to improve the cooling performance of the engine without deteriorating fuel consumption.

JP 2001-248596 A

  An object of the present invention is to provide an engine cooling system capable of improving engine cooling performance without deteriorating the fuel consumption of a large vehicle.

  The engine cooling system of the present invention that achieves the above object comprises a sub radiator through which cooling water for an intercooler flows, a radiator through which cooling water for an engine body flows, and a cooling fan, which are arranged in this order from the front of the vehicle. In an engine cooling system, a refrigerant pump, an evaporator, an expander connected to a generator, and a Rankine cycle in which refrigerant is circulated in order are provided, and an electric fan is used as the cooling fan, and an inlet side of the radiator A part of the cooling water is used as a heating source for the evaporator, and a part of the cooling water on the outlet side of the sub radiator is used as a cooling source for the condenser. And supplying the electric power to the electric fan, cooling water that has passed through the evaporator, and cooling water that has passed through the condenser, It is characterized in that for combining the outlet side cooling water in the radiator.

  According to the engine cooling system of the present invention, since the Rankine cycle operated by utilizing the temperature difference between the high-temperature cooling water circulating through the radiator and the low-temperature cooling water circulating through the sub-radiator is installed, Since a part of the cooling water is cooled by the Rankine cycle, which has a higher thermal efficiency than air cooling, the cooling performance is improved.

  In addition, since a margin is generated by improving the cooling performance, an electric fan driven by electric power generated in the Rankine cycle can be used instead of a conventional mechanical fan in a large vehicle, so that a diesel engine or an alternator can be used. Since the burden is reduced, the fuel efficiency will not deteriorate.

1 is a configuration diagram of an engine cooling system according to a first embodiment of the present invention. It is a block diagram of the engine cooling system which consists of a 2nd Embodiment of this invention. It is a flowchart explaining the 1st control content in the 2nd Embodiment of this invention. It is a flowchart explaining the 2nd control content in the 2nd Embodiment of this invention. It is a block diagram of the engine cooling system which consists of the 3rd Embodiment of this invention. It is a flowchart explaining the control content in the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an engine cooling system according to a first embodiment of the present invention.

  The engine cooling system 1A includes a sub-radiator 2, a radiator 3, and a cooling fan 4 arranged in order from the front of a large vehicle. The sub-radiator 2 and the radiator 3 cool the cooling water by air cooling using vehicle speed air or cooling air from a cooling fan.

  In the diesel engine 5 to be cooled by the engine cooling system 1A, the air A drawn into the intake passage 6 becomes the intake air 7 and is compressed by the compressor 9 of the turbocharger 8 after passing through an air cleaner (not shown). After being cooled by the water-cooled intercooler 10, it is supplied to the engine body 12 through the intake manifold 11.

  The intercooler cooling water 13 used for cooling in the intercooler 10 is forcibly circulated with the sub-radiator 2 by the water pump 15 while the temperature is adjusted by the intercooler thermostat 14.

  The intake air 7 supplied to the engine body 12 is mixed with fuel and combusted to generate thermal energy, then becomes combustion gas 16 and is exhausted from the exhaust manifold 17 to the exhaust passage 18, and the turbine of the turbocharger 8. After 19 is rotated, it becomes exhaust gas G and is released into the atmosphere.

  The engine main body cooling water 20 for cooling the engine main body 12 is forcibly circulated by the water pump 15 with the radiator 3 while the flow rate is adjusted by the thermostat 21. On the other hand, the cooling water 22 diverted from the thermostat 21 circulates without passing through the radiator 3.

  In such an engine cooling system 1A, the cooling fan 4 uses an electric fan that is rotationally driven not by the engine body 12 but by the electric motor 23.

  Further, a Rankine cycle 31 in which a refrigerant 30 circulates in order through a refrigerant pump 24, an evaporator 25, an expander 28 (turbine) connected to a generator 27 connected to a battery 26, and a condenser 29 includes a sub-radiator 2 and It is provided in parallel with a conventional engine cooling system composed of the radiator 3.

  Specifically, on the heating side of the evaporator 25 in the Rankine cycle 31, a part of the inlet side cooling water 32 (heated engine main body cooling water 20) of the radiator 3 is diverted from the upstream side of the thermostat 21. The cooling water 33 after passing through the evaporator 25 merges with the outlet side cooling water 34 (cooled engine body cooling water 20 after cooling) of the radiator 3. Further, on the cooling side of the condenser 29, a part of the outlet side cooling water 35 of the sub radiator 2 (cooled intercooler cooling water 13) is diverted from the vicinity of the inlet of the intercooler 10 and passes through the condenser 29. The subsequent cooling water 36 merges into the outlet side cooling water 34 of the radiator 3.

  The refrigerant 30 circulating in the Rankine cycle 31 is compressed by the refrigerant pump 24, is heated at a constant pressure by the inlet side cooling water 32 of the radiator 3 in the evaporator 25, becomes high-pressure superheated steam, and is adiabatically expanded by the expander 28. After the generator 27 is rotationally driven to generate electric power, the condenser 29 is cooled at a constant pressure by the outlet side cooling water 35 of the sub radiator 2 and returns to the liquid. The electric power generated by the generator 27 is charged in the battery 26 and then supplied to the electric motor 23 of the cooling fan 4 through an electric wire (shown by a dotted line).

  As described above, the Rankine cycle 31 operated by utilizing the temperature difference between the high-temperature cooling water circulating through the radiator 3 and the low-temperature cooling water circulating through the sub-radiator 2 is installed. Since a part of the cooling water 20 is cooled by the Rankine cycle 31 having higher thermal efficiency than air cooling, the cooling performance is improved. In addition, since a margin is generated by improving the cooling performance, an electric fan driven by electric power generated in the Rankine cycle can be used for the cooling fan 4 instead of the conventional mechanical fan in a large vehicle. Since driving of the fan by the main body 12 becomes unnecessary and power generation by the alternator is reduced, the load on the engine main body 12 is reduced and fuel consumption can be improved.

  FIG. 2 shows an engine cooling system according to a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same part as FIG. 1, and description is abbreviate | omitted.

  In the engine cooling system 1B, the cooling water 33 after passing through the evaporator 25 and the cooling water 36 after passing through the condenser 29 in the Rankine cycle 31 are sent to the outlet side cooling water 34 of the radiator 3 via the electromagnetic valve 37. I try to merge. Further, a water temperature meter 38 for measuring the temperature of the inlet side cooling water 32 of the radiator 3 is installed. The electromagnetic valve 37 and the water temperature gauge 38 are connected to the ECU 40 serving as a control unit together with the refrigerant pump 24 through a signal line (indicated by a one-dot chain line).

  The first control content by the ECU 40 will be described below with reference to FIG.

  The ECU 40 inputs the measured value of the water temperature gauge 38 (S10), and determines whether the measured value is equal to or higher than the temperature T1 at which the thermostat 21 is opened (S11). The temperature T1 is set in advance according to the specification of the vehicle, and for example, a value of about 80 ° C. is exemplified.

  If the measured value is equal to or higher than the temperature T1, it is determined that the cooling water 32 needs to be cooled, the electromagnetic valve 37 is opened (S12), and the refrigerant pump 24 is started (S13), thereby Rankine. The operation of cycle 31 is started (S14).

  By such control, the cooling water 32 can be cooled by the Rankine cycle 31 at an appropriate timing, so that the cooling performance of the engine cooling system 1B can be made efficient.

  On the other hand, when the measured value of the water temperature gauge 38 is lower than the temperature T1, it is determined that the engine body 12 is in the warm-up operation, and the electromagnetic valve 37 is closed until the measured value becomes equal to or higher than the temperature T1. Then, the operation of the Rankine cycle 31 is stopped (S17) by stopping the refrigerant pump 24 (S16).

  By such control, the warm-up operation of the engine body 12 is not hindered by the Rankine cycle 31, so that the warm-up of the engine body 12 can be completed at an early stage.

  The second control content by the ECU 40 will be described below based on FIG.

  The ECU 40 inputs a measured value of the storage rate (SOC) of the battery 26 (S20), and determines whether the storage rate is equal to or higher than a preset threshold value S (for example, 70 to 90%) (S21). ). When the storage rate is equal to or greater than the threshold value S, the operation of the Rankine cycle 31 is stopped by closing the solenoid valve 37 (S22) and stopping the refrigerant pump 24 (S23) (S24). The ECU 40 repeatedly executes these steps 20 to 24.

  By this second control, the operation of the Rankine cycle 31 is stopped while electric power sufficient to rotationally drive the cooling fan 4 is supplied. On the other hand, when the electric power is insufficient, the Rankine cycle 31 starts operation again. Therefore, the engine cooling system 1B can be efficiently operated.

  Note that the above first and second control contents may be performed simultaneously or sequentially in any order.

  FIG. 5 shows an engine cooling system according to a third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same part as FIGS. 1, 2, and description is abbreviate | omitted.

  In the engine cooling system 1 </ b> C, a part of the inlet side cooling water 35 of the radiator 3 is diverted from the downstream side of the thermostat 21 to the heating side of the evaporator 29 in the Rankine cycle 34. In addition, an electromagnetic valve 41 is provided at the outlet of the radiator 3 and is connected to the ECU 40 as a control means through a signal line (indicated by a one-dot chain line).

  The contents of control by the ECU 40 will be described below with reference to FIG.

  The ECU 40 inputs the measured value of the water temperature gauge 39 (S30), and determines whether the measured value is equal to or higher than the temperature T1 at which the thermostat 21 is opened (S31). When the measured value is equal to or higher than the temperature T1, the refrigerant pump 24 is activated (S32), and the operation of the Rankine cycle 31 is started (S33).

  On the other hand, when the measured value of the water temperature gauge 39 is lower than the temperature T1, the electromagnetic valve 41 is closed (S34), and the process returns to the start of control.

  Next, it is determined whether the measured value of the water thermometer 39 is equal to or higher than the temperature T2 at which the thermostat 21 is fully opened (S35). The temperature T2 is set in advance according to the specification of the vehicle. For example, a value of about 100 ° C. is exemplified.

  When the measured value is equal to or higher than the temperature T2, the solenoid valve 41 is opened (S36), and a part of the cooling water 32 is diverted to the radiator 3 (S37).

  On the other hand, when the measured value of the water temperature gauge 39 is equal to or higher than the temperature T1 and lower than the temperature T2, the electromagnetic valve 41 is closed (S34), and the process returns to the start of control.

  With such control, when the heat load of the engine body 12 is relatively low, while the cooling water 32 is cooled only by the Rankine cycle 31 having high thermal efficiency, the heat load of the engine body 12 becomes relatively high. Since the cooling water 32 is cooled even by air cooling by the radiator 3, the cooling performance of the engine cooling system 1C can be further improved.

1A, 1B, 1C Engine cooling system 2 Sub-radiator 3 Radiator 4 Cooling fan 10 Intercooler 12 Engine body 13 Intercooler cooling water 20 Engine body cooling water 21 Thermostat 24 Refrigerant pump 25 Evaporator 26 Battery 27 Generator 28 Expander 29 Condensation Unit 30 Refrigerant 31 Rankine cycle 32 Inlet side cooling water 34 (of the radiator) Outlet side cooling water 35 (of the radiator) Outlet side cooling water 38 (of the sub radiator) 38, 41 Solenoid valve 40 ECU

Claims (4)

In an engine cooling system in which a sub radiator through which cooling water for an intercooler flows, a radiator through which cooling water for an engine body flows, and a cooling fan are arranged in order from the front of the vehicle,
While providing a Rankine cycle in which refrigerant circulates in order through a refrigerant pump, an evaporator, an expander and a condenser connected to a generator, an electric fan is used as the cooling fan,
The Rankine cycle is operated by using a part of the cooling water on the inlet side of the radiator as a heating source for the evaporator and a part of the cooling water on the outlet side of the sub-radiator as a cooling source for the condenser. While generating electric power to the generator and supplying the electric power to the electric fan,
An engine cooling system characterized in that the cooling water that has passed through the evaporator and the cooling water that has passed through the condenser are merged with the outlet side cooling water of the radiator. A thermostat that adjusts the flow rate of cooling water flowing into the radiator, a water temperature meter that measures the temperature of cooling water that passes through the thermostat, cooling water that passes through the evaporator, and cooling water that passes through the condenser are A solenoid valve that adjusts the flow rate that merges with the outlet side cooling water of the radiator, and a control means;
The control means opens the solenoid valve when the measured value of the water thermometer is equal to or higher than the temperature T1 at which the thermostat is opened, while the measured value of the water thermometer is less than the temperature T1. 2. The engine cooling system according to claim 1, wherein the electromagnetic valve is closed until the measured value becomes equal to or higher than the temperature T <b> 1.   And a control means for controlling the Rankine cycle, wherein the control means supplies a part of the electric power generated by the generator to a battery connected to the electric fan, and the storage rate of the battery is preset. The engine cooling system according to claim 1, wherein the Rankine cycle is stopped when the threshold value is exceeded. A thermostat for adjusting the flow rate of the cooling water flowing into the radiator, a thermometer for measuring the temperature of the cooling water passing through the thermostat, an electromagnetic valve for adjusting the flow rate of the cooling water flowing out from the radiator, and a control means; With
The control means closes the electromagnetic valve when the measured value of the water thermometer is equal to or higher than a temperature T1 at which the thermostat is opened and is lower than a temperature T2 at which the thermostat is fully opened. The engine cooling system according to claim 1, wherein when the measured value of the meter is equal to or higher than the temperature T2, the electromagnetic valve is opened.