JP2010096139A - Cooling device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device for an engine efficiently cooling an exhaust manifold. <P>SOLUTION: This device includes a manifold bypass path 25 connecting a cooling liquid jacket 17 of the exhaust manifold to a downstream side of a heater 16 in a heater path 24 and bypassing the cooling liquid jacket 17 of the exhaust manifold. A valve means 18 operating to make cooling liquid flow to the cooling liquid jacket 17 at least when cooling of the exhaust manifold is demanded is disposed between an outlet of the heater 16 and an inlet of the cooling liquid jacket 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling device that cools an engine by circulating a coolant.

Conventionally, as a cooling device for this type of engine, for example, Patent Document 1 discloses a cooling device that circulates a coolant between an engine body and a radiator. In the cooling device disclosed in Patent Document 1, the exhaust manifold is a so-called water-cooled exhaust manifold in which a coolant jacket is formed, and a coolant passage branched from the middle of the engine body is used to cool the exhaust manifold. By connecting to the liquid jacket, the exhaust manifold is cooled by flowing the cooling liquid through the cooling liquid jacket. Here, the cooling device disclosed in Patent Document 1 is configured such that the coolant is always supplied to the coolant jacket in the exhaust manifold during the operation of the engine.
JP-A-6-241044

  However, it is desirable to cool the exhaust manifold when the engine is at full load, for example. However, when the engine is cold started, the exhaust temperature must be increased early in order to increase the catalyst temperature early. desirable. For this reason, it is preferable not to cool the exhaust manifold. However, in the cooling device disclosed in Patent Document 1, as described above, during the operation of the engine, the coolant is always supplied to the coolant jacket of the exhaust manifold. Since it is supplied, there is a disadvantage that the exhaust manifold is cooled even during cold start.

  The present invention has been made in view of such a point, and an object of the present invention is to efficiently cool the exhaust manifold.

  The present invention provides an exhaust manifold coolant jacket on the downstream side of the heater in the heater path provided on the outlet side of the engine body, and when the exhaust manifold cooling is required, the coolant jacket is provided. The valve means that operates to circulate the coolant is arranged between the heater outlet and the coolant jacket inlet.

  Specifically, according to one aspect of the present invention, an engine cooling device includes an engine body formed therein so that a flow path through which a coolant flows is connected between an inlet and an outlet, and the engine A pump that is provided on the inlet side of the main body and that discharges the cooling liquid sucked from the suction port by its drive from the discharge port, and a path that connects the outlet port of the engine body and the suction port of the pump to each other A radiator passage in which a radiator is interposed, a radiator bypass passage for connecting the outlet of the engine body and the suction port of the pump to each other, and bypassing the radiator; and the radiator In the route, it is provided in parallel with the high-temperature side flow path from the engine body to the radiator, and in the middle of the route, air conditioning for the passenger compartment Comprises a heater path that data is interposed, an exhaust manifold is attached to an exhaust side of the engine body.

  A cooling fluid jacket through which the cooling fluid flows so as to cool the exhaust manifold is formed inside the exhaust manifold, and the cooling fluid jacket of the exhaust manifold is disposed downstream of the heater on the heater path. It arranges in.

  The cooling device further includes a manifold bypass path that bypasses the coolant jacket in the heater path, and at least cooling of the exhaust manifold is required between the outlet of the heater and the inlet of the coolant jacket. Sometimes, a valve means is provided which operates to circulate the coolant through the coolant jacket.

  According to this configuration, a relatively low-temperature coolant after heat exchange in the heater flows to the coolant jacket of the exhaust manifold, and the exhaust manifold is effectively cooled.

  In particular, a valve means is interposed between the outlet of the heater and the inlet of the coolant jacket, and the coolant flows through the coolant jacket when the exhaust manifold is required to be cooled by the valve means. By doing so, the exhaust manifold is cooled when necessary.

  The valve means is preferably configured to limit the flow of the coolant to the coolant jacket when cooling of the exhaust manifold is not required.

  Here, the restriction on the flow of the coolant includes reducing the flow rate of the coolant in addition to blocking the flow of the coolant.

  By doing so, for example, when cooling of the exhaust manifold is not required, such as during cold start, the flow of the coolant to the coolant jacket is limited by the valve means, so that the exhaust manifold is cooled wastefully. For example, the catalyst temperature can be increased early by suppressing a decrease in the exhaust gas temperature.

  The cooling device further includes a thermostat valve interposed between the suction port side of the pump, a downstream end of the radiator path, and a downstream end of the radiator bypass path, and the thermostat valve When the temperature is equal to or lower than a predetermined temperature, the radiator bypass path side is opened and the radiator path is closed, and when the coolant temperature is higher than the predetermined temperature, the radiator bypass path side is closed. In addition, the radiator path may be configured to be opened, and the valve means may operate so as to circulate the coolant through the coolant jacket of the exhaust manifold at a temperature lower than the predetermined temperature.

  During the warming-up of the engine body whose cooling liquid temperature is equal to or lower than the predetermined temperature, the coolant flows by bypassing the radiator by the thermostat valve, so that the engine can be warmed up quickly while the temperature of the cooling liquid During normal operation of the engine body higher than the predetermined temperature, the engine body is effectively cooled by circulating the coolant between the engine body and the radiator by the thermostat valve.

  On the other hand, since the exhaust manifold has a relatively poor heat dissipation to the outside, the exhaust manifold may be hotter than the engine body, so the valve means is used at a temperature lower than a predetermined temperature at which the thermostat valve operates. Then, supply the coolant to the coolant jacket. By doing so, it is possible to prevent the coolant from boiling in the coolant jacket in the exhaust manifold.

  The valve means is a valve interposed between the outlet side of the heater, the inlet side of the coolant jacket, and the upstream end of the manifold bypass path, and the temperature of the coolant flowing out of the heater It is good also as being the 2nd thermostat valve which opens and closes according to this.

  By doing so, the cooling fluid is supplied to the exhaust manifold with a simple configuration when cooling is necessary.

  Alternatively, the valve means may be a control valve that operates based on a detection value of a liquid temperature sensor that detects the temperature of the coolant in the coolant jacket.

  By doing so, the coolant is supplied to the exhaust manifold more accurately and when cooling is necessary.

  As described above, according to the present invention, when at least cooling of the exhaust manifold is required by the valve means interposed between the outlet of the heater and the inlet of the coolant jacket, the coolant jacket is passed through the coolant jacket. Since the later relatively low-temperature coolant is supplied, the exhaust manifold can be effectively cooled when cooling is required.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 is a block diagram showing a configuration of an engine cooling device 1 according to an embodiment of the present invention, in which 11 is a cylinder block, and 12 is a cylinder head disposed above the cylinder block 11. The engine body 10 includes the cylinder block 11 and the cylinder head 12.

  Although not shown, a passage (coolant jacket) through which coolant flows is formed inside the engine body 10. The inlet of the coolant jacket is provided in the cylinder block 11. A pump (water pump) 13 is disposed on the inlet side of the coolant jacket, and the discharge port of the pump 13 is connected to the inlet of the coolant jacket. The pump 13 is drivingly connected to a crankshaft (not shown) and is driven by the crankshaft. By driving the pump 13, the coolant is supplied to the coolant jacket of the engine body 10 through the inlet.

  The coolant jacket of the engine body 10 is connected from the cylinder block 12 to the cylinder head 12 inside, and the outlet of the coolant jacket is provided in the cylinder head 12. The outlet of the coolant jacket is connected to the radiator 14 via a high-temperature channel 21 through which a relatively high-temperature coolant flows after passing through the engine body 10, and the downstream side of the radiator 14 is connected to the radiator 14. The refrigerant is connected to the suction port of the pump 13 via a low-temperature side passage 22 through which a relatively low-temperature coolant flows after passing through.

  Thus, a thermostat valve 15 is interposed between the radiator 14 and the pump 13. The radiator 14 is connected to the first inflow port of the thermostat valve 15, and the pump 13 is connected to the outflow port of the thermostat valve 15. It is connected.

  A high-temperature channel 21 and a low-temperature channel 22 connect the outlet of the engine body 10 and the suction port of the pump 13 to each other, and a radiator channel 20 is provided in which a radiator 14 is interposed. Will be.

  The high temperature side channel 21 is branched on the upstream side of the radiator 14, and the branched channel is connected to the second inflow port of the thermostat valve 15. The branch flow path forms a radiator bypass path 23 that connects the outlet of the engine body 10 and the suction port of the pump 13 to each other and bypasses the radiator 14.

  Although not shown, the thermostat valve 15 is a known wax type. When the cooling water temperature is equal to or lower than a predetermined temperature, the wax contracts, and the urging force of the spring moves the valve body in the axial direction of the spring. The first inflow port is closed and the second inflow port is opened. Thus, the radiator bypass path 23 side is communicated with the pump 13. On the other hand, when the cooling water temperature becomes higher than a predetermined temperature, the valve body moves in the axial direction of the spring due to the expansion of the wax to open the first inflow port and close the second inflow port. Thus, the radiator path 20 side is communicated with the pump 13. Thus, the thermostat valve 15 selectively opens the first and second inflow ports according to the coolant temperature.

  In addition, a heater path 24 is provided in parallel to the high temperature side flow path 21, and a heater 16 for vehicle compartment air conditioning is interposed in the heater path 24.

  Thus, an exhaust manifold for discharging burned gas in each cylinder is attached to the exhaust side of the engine body 10. Although not shown in the drawing, the exhaust manifold is formed with a coolant jacket 17 through which coolant for cooling the exhaust manifold flows. That is, this exhaust manifold is a water-cooled exhaust manifold.

  The coolant jacket 17 is arranged on the downstream side of the heater 16 in the heater path 24. Further, the downstream side of the heater 16 in the heater path 24 is branched, and the branched path joins again at the outlet side of the coolant jacket 17 of the exhaust manifold, thereby forming a manifold bypass path 25 that bypasses the coolant jacket 17. It is composed. Thus, the second thermostat valve 18 is disposed at the branch position of the manifold bypass path 25. Specifically, the heater 16 is at the inflow port of the second thermostat valve 18, the coolant jacket 17 of the exhaust manifold is at the first outflow port of the second thermostat valve 18, and the manifold bypass path 25 is at the second The thermostat valve 18 is connected to a second outlet port.

  Although not shown, the second thermostat valve 18 is also a known wax type, and when the cooling water temperature is equal to or lower than the (second) predetermined temperature, the wax contracts and the valve body is biased by the biasing force of the spring. Moves in the axial direction of the spring to close the first outflow port and open the second outflow port. As a result, the coolant flows through the manifold bypass path 25 side. On the other hand, when the cooling water temperature becomes higher than the (second) predetermined temperature, the valve body moves in the axial direction of the spring due to the expansion of the wax to open the first outflow port and close the second outflow port. This causes the coolant to flow through the coolant jacket 17 of the exhaust manifold. Thus, the second thermostat valve 18 selectively opens the first and second outflow ports according to the coolant temperature.

  Here, the composition of the wax of the second thermostat valve 18 is different from the composition of the wax in the thermostat valve 15, whereby the second thermostat valve 18 has a predetermined temperature that is the operating temperature of the thermostat valve 15. The valve is controlled to open at a second predetermined temperature T2 lower than the temperature T1. The second predetermined temperature T2 may be appropriately set as a temperature at which the coolant does not boil in the coolant jacket 17 of the exhaust manifold.

  The operation of the engine cooling device 1 having the above configuration will be described. First, when the temperature of the coolant at the time of starting the engine body 10 is equal to or lower than a predetermined temperature, the radiator bypass path 23 is communicated with the pump 13 by the thermostat valve 15. Since the radiator path 20 side is cut off, the coolant flowing into the engine body 10 by driving the pump 13 returns to the pump 13 through the engine body 10, the radiator bypass path 23, and the thermostat valve 15 in order. Thus, since the coolant does not pass through the radiator 14, the temperature of the coolant rises quickly, and the engine body 10 warms up early.

  Further, since the temperature of the coolant in the coolant jacket 17 of the exhaust manifold is relatively low, the second thermostat valve 18 is closed, whereby a part of the coolant flowing out from the engine body 10 is heated by the heater. After passing 16, it flows to the engine body 10 through the manifold bypass path 25. Accordingly, the exhaust temperature is prevented from lowering by preventing the coolant from passing through the coolant jacket 17 of the exhaust manifold, and although not shown, the temperature of the catalyst provided on the exhaust side is increased early. Can do. Thereby, the emission property can be improved.

  Then, as the engine body 10 is warmed up, the temperature of the coolant gradually increases. Then, when the coolant after passing through the heater 16 becomes equal to or higher than the second predetermined temperature T2 described above, the second thermostat valve 18 is opened. As a result, the relatively low temperature coolant that has passed through the heater 16 flows to the coolant jacket 17 of the exhaust manifold. Thus, after cooling the exhaust manifold there, it flows to the engine body 10.

  When the temperature of the coolant further rises and becomes equal to or higher than the predetermined temperature T1 (predetermined temperature T1> second predetermined temperature T2), the thermostat valve 15 causes the radiator path 20 to communicate with the pump 13 and the radiator. The bypass path 23 side is blocked. Therefore, the coolant that has passed through the engine body 10 and the coolant jacket 17 of the exhaust manifold is supplied to the radiator 14, and the coolant whose temperature has been reduced by heat exchange there is supplied to the engine body 10. . Thus, the exhaust manifold and the engine body 10 are effectively cooled.

  Thus, in this cooling device 1, since the coolant having a relatively low temperature after passing through the heater 16 is supplied to the coolant jacket 17 of the exhaust manifold, the exhaust manifold can be efficiently cooled. become. In particular, although the exhaust manifold is not shown in the drawing, a fastening bolt is arranged in a staggered manner on the cylinder head 12 in, for example, a line arranged in a line, and is attached to the engine body 10. For each one, it is often difficult to provide the coolant jacket 17 so as to surround it, and there is a possibility that the cooling efficiency of the exhaust manifold may be lowered. By supplying to the jacket 17, the exhaust manifold can be efficiently cooled.

  Also, a second thermostat valve 18 is provided upstream of the exhaust manifold coolant jacket 17. When the exhaust manifold is required to be cooled by the second thermostat valve 18, the exhaust manifold coolant jacket 17 is provided. When cooling of the exhaust manifold is not required, the coolant is not supplied to the coolant jacket 17 of the exhaust manifold. For example, during cold start, the exhaust temperature is increased to increase the catalyst temperature. It can be raised early.

  In particular, although the temperature of the exhaust manifold is likely to be higher than that of the engine body 10, the exhaust manifold is set by setting the operating temperature of the second thermostat valve 18 to be lower than the operating temperature of the thermostat valve 15. Therefore, it is possible to prevent the coolant from boiling in the coolant jacket 17 of the exhaust manifold.

  In the above-described embodiment, the second thermostat valve 18 is provided at the branch position in the heater path 24. However, for example, as shown virtually in FIG. 1, the second thermostat valve 18 is used instead. The control on-off valve 18 ′ may be interposed on the coolant jacket 17 side of the exhaust manifold from the branch position of the manifold bypass path 25. The on-off valve 18 ′ may be configured to be controlled to open and close according to a detection value of a liquid temperature sensor 19 that detects the temperature of the coolant in the coolant jacket 17 of the exhaust manifold, for example. As described above, the on-off valve 18 'is preferably controlled to open at a second predetermined temperature T2 lower than the predetermined temperature T1, which is the operating temperature of the thermostat valve 15. By doing so, it is possible to prevent the coolant from boiling in the coolant jacket 17 of the exhaust manifold.

  As described above, the present invention can efficiently cool the exhaust manifold when cooling is necessary, and is therefore useful as a cooling device for an engine equipped with a so-called water-cooled exhaust manifold.

It is a block diagram which shows the structure of the cooling device of the engine which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling device 10 Engine main body 13 Pump 14 Radiator 15 Thermostat valve 16 Heater 17 Coolant jacket 18 of exhaust manifold Second thermostat valve (valve means)
18 'On-off valve (control valve)
19 Liquid temperature sensor 20 Radiator path 21 High temperature side path 23 Radiator bypass path 24 Heater path 25 Manifold bypass path

Claims (5)

An engine body formed therein so that a flow path through which the coolant flows connects the inlet and the outlet to each other;
A pump that is provided on the inlet side of the engine body and that discharges the cooling liquid sucked from the suction port by its drive;
A path connecting the outlet of the engine body and the suction port of the pump to each other, a radiator path having a radiator interposed in the middle thereof;
A radiator bypass path for connecting the outlet of the engine body and the suction port of the pump to each other and bypassing the radiator;
A heater path provided in parallel with the high-temperature side flow path from the engine body to the radiator in the radiator path;
An exhaust manifold attached to the exhaust side of the engine body,
Inside the exhaust manifold is formed a coolant jacket through which the coolant flows to cool the exhaust manifold,
The coolant jacket of the exhaust manifold is disposed downstream of the heater on the heater path,
A manifold bypass path that bypasses the coolant jacket in the heater path;
Between the outlet of the heater and the inlet of the coolant jacket, valve means is provided for operating the coolant to flow through the coolant jacket at least when cooling of the exhaust manifold is required. Engine cooling system. The engine cooling device according to claim 1,
The engine cooling device is configured to limit the flow of the coolant to the coolant jacket when the exhaust manifold is not required to be cooled. The engine cooling device according to claim 1 or 2,
A thermostat valve interposed between the suction port side of the pump, the downstream end of the radiator path, and the downstream end of the radiator bypass path;
The thermostat valve opens the radiator bypass path side and closes the radiator path when the temperature of the coolant is lower than a predetermined temperature, and when the temperature of the coolant becomes higher than the predetermined temperature. , Configured to close the radiator bypass path side and open the radiator path,
The engine is a cooling device for an engine that operates so as to circulate a coolant through a coolant jacket of the exhaust manifold at a temperature lower than the predetermined temperature. The engine cooling device according to claim 3.
The valve means is a valve interposed between the outlet side of the heater, the inlet side of the coolant jacket, and the upstream end of the manifold bypass path, and the temperature of the coolant flowing out of the heater A cooling device for the engine, which is a second thermostat valve that opens and closes in response to the above. The engine cooling device according to claim 3.
The engine cooling apparatus, wherein the valve means is a control valve that operates based on a detection value of a liquid temperature sensor that detects a temperature of a coolant in a coolant jacket of the exhaust manifold.

Images