JP2015101960A - Cooling device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply cooling water at a suitable temperature to each portion of an internal combustion engine while reducing the number of pumps and radiators.SOLUTION: A cooling device 5 of an internal combustion engine includes: one cooling water pump 53; one radiator 513 for radiating heat of cooling water; a first cooling water passage 51 having flow control valves 511 and 512 on an inlet side and an outlet side respectively and passing through a cylinder block 61, the radiator 513, and a portion 515 in the vicinity of an exhaust port in a cylinder head; a second cooling water passage 52 having flow control valves 521 and 522 on an inlet side and an outlet side respectively and passing through a heater 523 and a portion 524 in the vicinity of an intake port in the cylinder head; a heat exchanger 54 for exchanging heat between cooling water in the second cooling water passage 52 and the cooling water in the first cooling water passage 51; and a change-over valve 525 for switching between a state for exchanging and a state for not exchanging heat between the cooling water in the second cooling water passage 52 and the cooling water in the first cooling water passage 51.

Description

  The present invention relates to a cooling device for a water-cooled (liquid-cooled) internal combustion engine.

  2. Description of the Related Art In a water-cooled internal combustion engine mounted on a vehicle, a cylinder block, an intake port and an exhaust port of a cylinder head, an EGR (Exhaust Gas Recirculation) cooler, and the like are cooled by circulating cooling water (coolant). Cooling water that has received heat from various parts of the internal combustion engine and has been heated to heat is radiated by the radiator. It is also common to use this cooling water to heat heaters for interior heating, transmission fluids, and the like.

  Originally, the optimum temperature of the cooling water to be supplied to various parts of the internal combustion engine is not uniform. For example, the temperature difference between the intake port and the exhaust port is very large. Nevertheless, if cooling water having the same temperature is supplied to both the intake ports, there is a concern that the intake ports will rise in temperature and cause a reduction in the charging efficiency of the intake air.

  Therefore, as disclosed in the following patent document, it is conceivable to divide the cooling water path of the internal combustion engine into a plurality of parts. Then, the temperature of the cooling water flowing through each path can be made different, and it becomes easy to distribute the cooling water having a suitable temperature to each part of the internal combustion engine. That is, it is possible to provide cooling water from the path through which relatively low-temperature cooling water flows to the intake port side, and supply cooling water from the path through which relatively high-temperature cooling water flows to the exhaust port side. Become.

  However, by disposing a pump and a radiator in each cooling water path, the cooling device becomes large as a whole, and it becomes difficult to accommodate it in a limited engine room. Of course, we cannot overlook the increase in weight and cost. In addition, as a result of the plurality of radiators being scattered in the engine room, there is also a side effect that the temperature of the engine room increases as a whole, the temperature of the intake air flowing through the intake passage rises, and the charging efficiency decreases.

JP 2013-133747 A

  An object of the present invention is to make it possible to supply cooling water having a suitable temperature to various parts of an internal combustion engine while reducing the number of pumps and radiators.

  In order to solve the above-described problems, in the present invention, one pump that discharges and pumps cooling water, one radiator that dissipates the cooling water, an inlet side that is connected to the discharge port of the pump, and an outlet side that is connected to the suction port Each of which is provided with a flow control valve, each of a first cooling water path passing through the vicinity of an exhaust port in the cylinder block, the radiator and the cylinder head, an inlet side connected to the discharge port of the pump, and an outlet side connected to the suction port Is provided with a flow control valve for exchanging heat between the cooling water in the second cooling water path and the second cooling water path passing through the vicinity of the intake port in the heater and cylinder head and the cooling water in the first cooling water path. Switching for switching between a state in which heat is exchanged and a state in which heat is not exchanged between the cooling water in the second cooling water path and the cooling water in the first cooling water path To constitute a cooling apparatus for an internal combustion engine provided and.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to supply the cooling water of the suitable temperature to each place of an internal combustion engine, reducing the number of pumps and radiators.

The figure which shows schematic structure of the internal combustion engine in one Embodiment of this invention. The figure which shows the structure of the drive system of the vehicle in the embodiment. The figure which shows the structure of the cooling device of the internal combustion engine of the embodiment.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an internal combustion engine for a vehicle in the present embodiment. The internal combustion engine in the present embodiment is a spark ignition type four-stroke engine and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel is provided. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode. The ignition coil is integrally incorporated in a coil case together with an igniter that is a semiconductor switching element.

  The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. On the intake passage 3, an air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream.

  The exhaust passage 4 for discharging the exhaust guides the exhaust generated by burning the fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and an exhaust purification three-way catalyst 41 are disposed on the exhaust passage 4.

  An external EGR device 2 is attached to the internal combustion engine of the present embodiment. The EGR device 2 realizes a so-called high-pressure loop EGR, and an EGR passage 21 that connects the upstream side of the catalyst 41 in the exhaust passage 4 and the downstream side of the throttle valve 32 in the intake passage 3, and the EGR passage 21 The EGR cooler 22 provided and the EGR valve 23 that opens and closes the EGR passage 21 and controls the flow rate of the EGR gas flowing through the EGR passage 21 are used as elements. The inlet of the EGR passage 21 is connected to the exhaust manifold 42 in the exhaust passage 4 or a predetermined location downstream thereof. The outlet of the EGR passage 21 is connected to a predetermined location downstream of the throttle valve 32 in the intake passage 3, specifically to a surge tank 33. The EGR cooler 22 cools the EGR gas using the cooling water of the internal combustion engine, and thereby suppresses the temperature of the intake air mixed with the EGR gas.

  FIG. 2 shows an example of a drive system provided in the vehicle. This drive system includes a torque converter 7 and automatic transmissions 8 and 9. As components of the automatic transmissions 8 and 9, a forward / reverse switching device 8 using a planetary gear mechanism and a belt type CVT (Continuously Variable Transmission) 9 which is a type of continuously variable transmission are adopted.

  The rotational torque output from the internal combustion engine is input from the crankshaft of the internal combustion engine to the pump impeller 71 on the input side of the torque converter 7 and transmitted to the turbine runner 72 on the output side. The rotation of the turbine runner 72 is transmitted to the drive shaft 94 of the CVT 9 via the forward / reverse switching device 8 and rotates the driven shaft 95 through a shift in the CVT 9. The rotation of the driven shaft 95 is transmitted to the output gear 101. The output gear 101 meshes with the ring gear 102 of the differential device, and rotates the axle 103 and the drive wheels (not shown) via the differential device.

  The hydraulic fluid (hydraulic fluid) supplied to the forward brake 84 or the reverse clutch 85 to switch the travel range (ie, forward, reverse, or neutral) and the hydraulic servos 913 and 923 to operate the gear ratio A hydraulic pump (not shown) that discharges and pumps the supplied hydraulic fluid is a known mechanical (non-electric) type that operates by receiving torque transmitted from a crankshaft of an internal combustion engine. This hydraulic fluid is a transmission fluid (CVT fluid) common to the fluid used in the torque converter 7. The transmission fluid is warmed using a cooling water of the internal combustion engine in a fluid warmer (CVT warmer) 514 at the time of cold start.

  FIG. 3 schematically shows the configuration of the cooling device 5 for an internal combustion engine in the present embodiment. The cooling device 5 according to the present embodiment includes one cooling water pump 53 that discharges and pumps cooling water, one radiator 513 that radiates the cooling water, and a first cooling water path that distributes relatively high-temperature cooling water. 51, heat exchange between the cooling water flowing through the first cooling water path 51 and the cooling water flowing through the second cooling water path 52 and the second cooling water path 52 through which the relatively low-temperature cooling water flows. And a switching valve 525 for switching between a state of performing heat exchange by the heat exchanger 54 and a state of not performing the heat exchange.

  The pump 53 is a known mechanical (non-electric) type that operates by receiving torque from the crankshaft of the internal combustion engine. The radiator 513 is arranged behind the front grille in the engine room of the vehicle, and naturally cools the cooling water by using running wind blown into the engine room, or forcibly cools the cooling water by using the wind generated by the electric fan. To do.

  The first cooling water passage 51 is connected to the cylinder block 61, the radiator 513 and / or the fluid warmer 514, the heat exchanger 54, and the cylinder head 62 containing the plurality of cylinders 1 from the inlet side connected to the discharge port of the pump 53. The exhaust head 515 which is a part near the exhaust port is sequentially passed to the outlet side connected to the suction port of the pump 53. Flow rate control valves 511 and 512 such as linear solenoid valves are provided on the inlet side and the outlet side of the second cooling water passage 52, respectively.

  Downstream of the cylinder block 61, the flow branches to a flow path that passes through the radiator 513 toward the heat exchanger 54 and a flow path that passes through the fluid warmer 514 toward the heat exchanger 54. Thermostat valves 516 and 517 are provided upstream of the radiator 513 and upstream of the fluid warmer 514, respectively. The thermostat valves 516 and 517 are both opened when the temperature of the surrounding cooling water exceeds the threshold value and closed when the temperature does not exceed the threshold value, but the thermostat valve 517 located upstream of the fluid warmer 514. Open at a lower water temperature than the thermostat valve 516 located upstream of the radiator 513.

  In addition, downstream from the cylinder block 61, a flow path that bypasses the radiator 513, the fluid warmer 514, and the heat exchanger 54 toward the exhaust head 515 is separately laid. When both the thermostat valves 516 and 517 are closed, the cooling water flows from the cylinder block 61 into the flow path and reaches the exhaust head 515 directly.

  Accordingly, the first water temperature sensor 518 for detecting the temperature of the cooling water flowing through the first cooling water path 51 is installed on the flow path from the exhaust head 515 toward the outlet side in the first cooling water path 51.

  The second cooling water path 52 extends from the inlet side connected to the discharge port of the pump 53 to a heater (heater core) 523 for heating a vehicle interior, a heat exchanger 54, and an intake head that is a part near the intake port of the cylinder head 62. 524 and the EGR cooler 22 are sequentially passed to the outlet side connected to the suction port of the pump 53. Flow rate control valves 521 and 522 such as linear solenoid valves are also provided on the inlet side and the outlet side of the second cooling water passage 52, respectively.

  Downstream of the heater 523, the flow branches to a flow path that passes through the heat exchanger 54 and goes to the intake head 524 and a flow path that bypasses the heat exchanger 54 and goes to the intake head 524. And the switching valve 525 is provided in the branch location. The switching valve 525 causes the cooling water flowing down from the heater 523 to flow into the heat exchanger 54 or to flow into a flow path that bypasses the heat exchanger 54 (that is, does not flow into the heat exchanger 54 and bypasses it). For example, a directional switching valve using a solenoid can be selectively switched.

  Accordingly, the second water temperature sensor 526 that detects the temperature of the cooling water flowing through the second cooling water path 52 is installed on the flow path from the EGR cooler 22 toward the outlet side in the second cooling water path 52.

  An ECU (Electronic Control Unit) 0 that controls operation of the internal combustion engine is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like.

  The input interface includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal b output from an engine rotation sensor that detects the rotation angle and engine speed of the crankshaft, and depression of an accelerator pedal. The accelerator opening signal c output from the sensor that detects the amount or the opening of the throttle valve 32 as the accelerator opening (so-called required load), the intake air temperature and the intake pressure in the intake passage 3 (particularly, the surge tank 33). Intake air temperature / intake pressure signal d output from the temperature / pressure sensor to be detected, cooling water temperature signal e output from the first water temperature sensor 518 for detecting the cooling water temperature on the first cooling water path 51, and the second cooling water path The cooling water temperature signal f output from the second water temperature sensor 526 that detects the cooling water temperature on 52, and the vibration of the cylinder block 61 that encloses each cylinder 1 Vibration signal g output from a knock sensor for detecting the cam angle signal h or the like to be output from the cam angle sensor is input in a plurality of cam angle of the intake camshaft or an exhaust camshaft.

  From the output interface, an ignition signal i for the igniter of the spark plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and an opening operation signal l for the EGR valve 23. The opening operation signals m, n, o, and p are output to the flow control valves 511, 512, 521, and 522 of the cooling device 5, and the direction switching signal q is output to the switching valve 525.

  The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 acquires various information a, b, c, d, e, f, g, and h necessary for operation control of the internal combustion engine via the input interface, knows the engine speed, and is filled in the cylinder 1. Estimate the intake volume. Based on the engine speed, the intake air amount, and the like, various operating parameters such as required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, ignition timing, and the like are determined. . The ECU 0 applies various control signals i, j, k, l, m, n, o, p, q corresponding to the operation parameters via the output interface.

  In the present embodiment, the ECU 0 operates the opening degree of the flow control valves 511, 512, 521, and 522 of the cooling device 5 and operates the direction of the flow path of the cooling water by the switching valve 525. Cooling water having a suitable temperature is supplied to each part. Hereinafter, the control of the cooling device 5 will be described in detail.

<1. Before warming up internal combustion engine>
The cooling water temperature on the first cooling water path 51 indicated by the first water temperature sensor 518 is lower than a relatively low predetermined value, and / or the cooling water temperature on the second cooling water path 52 indicated by the second water temperature sensor 526 is compared. When the temperature is lower than a predetermined value (typically, immediately after the cold start), the flow control valves 511 and 512 are fully closed to stop the circulation of the cooling water in the first cooling water path 51, The internal combustion engine is warmed up, that is, the temperature of the cooling water is increased.
Since the cooling water temperature is low, the thermostat valves 516 and 517 on the first cooling water passage 51 are closed.
The cooling water discharged from the mechanical pump 53 is circulated in the second cooling water passage 52. Therefore, the flow control valves 521 and 522 are opened greatly.
Further, the switching valve 525 on the second cooling water path 52 is operated in a direction in which the cooling water flows into the heat exchanger 54, and the cooling water in the second cooling water path 52 and the cooling water in the first cooling water path 51 are Heat exchange is possible between the two.

<2. After warming up the internal combustion engine, high temperature and high load operating range>
The cooling water temperature on the first cooling water path 51 exceeds a relatively high predetermined value, and / or the cooling water temperature on the second cooling water path 52 exceeds a relatively high predetermined value, and the accelerator opening degree Is larger than a predetermined value (in particular, fully open or close to full open), all the flow control valves 511, 512, 521, 522 are opened widely, and cooling in the first cooling water passage 51 and the second cooling water passage 52 is performed. Strengthen water circulation and promote cooling water temperature drop.
Since the coolant temperature is high, the thermostat valves 516 and 517 on the first coolant passage 51 are open.
The switching valve 525 on the second cooling water path 52 is operated in a direction in which the cooling water flows into the heat exchanger 54, and between the cooling water in the second cooling water path 52 and the cooling water in the first cooling water path 51. Heat exchange is possible.

<3. After the internal combustion engine is warmed up, the operating region where there is no high temperature and high load, the coolant temperature on the second coolant passage 52 is relatively low>
None of the above-mentioned conditions of “1. Before warming up the internal combustion engine” or “2. After warming up the internal combustion engine and operating region of high temperature and high load” is satisfied, and the cooling water temperature on the second cooling water passage 52 Is lower than the cooling water temperature on the first cooling water passage 51, the flow control valves 521 and 522 are opened greatly, while the flow control valves 511 and 512 are throttled to a smaller opening.
The thermostat valves 516 and 517 on the first cooling water path 51 are opened and closed according to the temperature of the cooling water flowing through the first cooling water path 51.
The fact that the cooling water temperature on the second cooling water path 52 is lower than the cooling water temperature on the first cooling water path 51 means that relatively low-temperature cooling water can be supplied to the heater 523, the intake head 524, and the EGR cooler 22. It can be evaluated that the situation is desirable. In order to maintain this, the switching valve 525 on the second cooling water path 52 is operated in a direction in which the cooling water does not flow into the heat exchanger 54, so that the cooling water and the first cooling water path in the second cooling water path 52. The heat exchange with the 51 cooling water is impossible.

<4. After the internal combustion engine is warmed up, the operating region where there is no high temperature and high load, the coolant temperature on the second coolant passage 52 is relatively low>
None of the above-mentioned conditions of “1. Before warming up the internal combustion engine” or “2. After warming up the internal combustion engine and operating region of high temperature and high load” is satisfied, and the cooling water temperature on the second cooling water passage 52 Is higher than or substantially equal to the cooling water temperature on the first cooling water passage 51, the flow control valves 511 and 512 are opened widely, while the flow control valves 521 and 522 are throttled to a smaller opening. .
The thermostat valves 516 and 517 on the first cooling water path 51 are opened and closed according to the temperature of the cooling water flowing through the first cooling water path 51.
The situation where the cooling water temperature on the second cooling water path 52 is higher than the cooling water temperature on the first cooling water path 51 needs to be corrected promptly. Therefore, the switching valve 525 on the second cooling water path 52 is operated in a direction in which the cooling water flows into the heat exchanger 54, and the cooling water in the second cooling water path 52 and the cooling water in the first cooling water path 51 are Heat exchange is possible between the two.

  In this embodiment, a flow rate is supplied to each of one pump 53 that discharges and pumps cooling water, one radiator 513 that dissipates the cooling water, and an outlet side that is connected to the discharge port of the pump 53 and an outlet side that is connected to the suction port. Control valves 511 and 512 are provided, and the first cooling water path 51 that passes through the vicinity of the exhaust port 515 in the cylinder block 61, the radiator 513, and the cylinder head 62, and the inlet side and the suction port connected to the discharge port of the pump 53 Flow rate control valves 521 and 522 are provided on each of the continuous outlet sides, and the second cooling water path 52 that passes through the vicinity of the intake port 524 in the heater 523 and the cylinder head 62, and the cooling water in the second cooling water path 52 are A heat exchanger 54 for exchanging heat with the cooling water in the first cooling water path 51; the cooling water in the second cooling water path 52; To constitute a cooling device 5 of the internal combustion engine and a switching valve 525 for switching between a state in which no state and heat exchanger for exchanging heat between the cooling water of 却水 path 51.

  According to the present embodiment, since only one pump 53 and one radiator 513 are required, it is possible to avoid an increase in size and weight of the cooling device 5 and to suppress an increase in cost.

  In addition, cooling water having a suitable temperature can be distributed to various parts of the internal combustion engine. In particular, it is possible to supply relatively low-temperature cooling water to the intake port vicinity 524 and the EGR cooler 22, and the EGR gas flowing in the intake port vicinity 524 and the EGR passage 21 is cooled well, and the intake air charged into the cylinder 1 is filled. The temperature rise is suppressed and the filling efficiency can be maintained high. Moreover, heat exchange between the cooling water in the second cooling water path 52 and the cooling water in the first cooling water path 51 is interrupted when it is desired to increase the actual compression ratio or when knocking is expected. And since it can prevent that the cooling water of the 2nd cooling water path 52 receives heat from the cooling water of the 1st cooling water path 51, it is effective in the improvement of an actual compression ratio, and prevention of knocking.

  The present invention is not limited to the embodiment described in detail above. The specific configuration of each part can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to an internal combustion engine mounted on a vehicle or the like.

0 ... Control unit (ECU)
DESCRIPTION OF SYMBOLS 5 ... Cooling device 51 ... 1st cooling water path 511, 512 ... Flow control valve 513 ... Radiator 515 ... Exhaust port vicinity (exhaust head)
52 ... Second cooling water path 521, 522 ... Flow rate control valve 523 ... Heater 524 ... Near intake port (intake head)
525 ... Switching valve 53 ... Pump 54 ... Heat exchanger 61 ... Cylinder block 62 ... Cylinder head

Claims (1)

One pump that discharges cooling water and pumps it,
One radiator that dissipates cooling water,
A flow rate control valve is provided on each of the inlet side connected to the discharge port of the pump and the outlet side connected to the suction port, and a first cooling water path passing through the vicinity of the exhaust port in the cylinder block, the radiator, and the cylinder head,
A flow rate control valve is provided on each of the inlet side connected to the discharge port of the pump and the outlet side connected to the suction port, and a second cooling water path passing through the vicinity of the intake port in the heater and the cylinder head,
A heat exchanger for exchanging heat of the cooling water of the second cooling water path with the cooling water of the first cooling water path;
A cooling device for an internal combustion engine, comprising: a switching valve for switching between a state in which heat is exchanged between the cooling water in the second cooling water path and the cooling water in the first cooling water path and a state in which heat is not exchanged.

Images