JP2006307865A - Small ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small ship equipped with an engine cooling structure with which dispersion of temperature and temperature distribution are hardly produced at a time of start and in a time of continuous operation under a full throttle open condition or a condition close to the same. <P>SOLUTION: In the small ship constructed to inject water pressurized and accelerated by a water jet pump P driven by an engine E from a rear injection port and to propel by reaction force thereof, a cylinder block Cb part of the engine E is constructed as an indirect cooling structure and an exhaust system part such as a cylinder head Ch and an exhaust manifold Em is constructed as a direct cooling structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a small boat such as a personal watercraft (also referred to as PWC) that jets a water flow backward and sails on the water by reaction thereof, and particularly relates to a cooling structure of the engine or the like.

  2. Description of the Related Art Small ships, for example, a jet propulsion type personal watercraft, which is one type thereof, have been frequently used in recent years for leisure, sports or rescue. This jet propulsion type personal watercraft generally propels a hull by injecting water sucked from a water inlet provided on the bottom of the boat under pressure by a water jet pump and accelerating it backwards.

And in the case of this jet propulsion type personal watercraft, the steering nozzle arranged behind the water jet pump injection port is swung left and right by operating the bar type steering handle left and right, Change the water injection direction to the left and right and steer the boat to the right or left. There are the following patent documents as prior art documents of this type.
JP 2000-110558 A

By the way, in a small vessel including the jet propulsion type personal watercraft, the propulsion engine has a temperature of each part of the engine and a temperature distribution state when the engine is started and during continuous operation in a state where the engine is fully opened or close thereto. Different.
As described above, if the temperature of each part of the engine and the temperature distribution state are different between when the engine is started and when the engine is fully opened or close to it, subtle deformation may occur in the engine. In particular, the subtle deformation of the cylinder bore causes noise, etc., because the clearance between the piston and cylinder is made as small as possible in the case of an engine that reduces the amount of lubricating oil consumption or measures against piston wrap noise. May appear.

  The present invention has been made in view of such a situation, and has a cooling structure for an engine that does not easily cause "variation" in temperature and temperature distribution during start-up and during continuous operation in a fully open state or a state close thereto. The purpose is to provide a small ship.

The said subject can be solved by the small ship which consists of the following structures. That is,
A small boat according to the first invention is a small boat configured to be propelled by a water jet pump driven by an engine.
The cylinder block portion of the engine has an indirect cooling structure, and the exhaust system portion has a direct cooling structure.

  Thus, according to the small vessel configured as described above, the cylinder block portion of the engine has an indirect cooling structure. The “variation” of the temperature distribution is reduced, and the deformation of the cylinder bore can be reduced. As a result, the clearance between the piston and the cylinder can be made as small as possible, and it becomes easy to reduce the amount of lubricating oil consumption or take measures against piston wrap noise. Further, since the exhaust system portion employs a direct cooling structure to increase the cooling capacity, it is possible to effectively cool the exhaust system whose temperature increases.

  Further, in the small vessel, when the cylinder head portion of the engine has a direct cooling structure, the cylinder head portion that becomes high temperature due to passage of exhaust gas can be effectively cooled.

  Further, in the small vessel, when the primary cooling liquid of the indirect cooling structure is oil and the oil is circulated in the closed circuit by the oil pump, the temperature distribution of each part of the cylinder block is “variation” due to the oil cooling. This is an effective configuration for reducing the amount of noise.

  In the small vessel, the primary cooling liquid of the indirect cooling structure may be cooling water, and the cooling water may be circulated in a closed circuit by a cooling water circulation pump. In such a case, inexpensive water can be used as the coolant.

  Further, in the small vessel, an engine lubrication circuit is used as the closed circuit, and is supplied from the oil tank to the cylinder block via the feed pump, and then the lubrication part of the engine is lubricated. When configured to recirculate into the oil tank via the scavenge pump, it is possible to realize a configuration in which the oil pump for oil circulation can be omitted.

  Further, in the small vessel, the small vessel is a jet propulsion type small vessel, and a heat exchanger is provided in a part of the closed circuit, and the heat exchanger is used as a water jet pump for jet propulsion. If it arrange | positions so that it may adhere to (attach) the casing of this, while exchanging heat effectively by the water which flows in the water jet pump, it becomes a heat exchanger which can reduce a number of parts and can be implemented cheaply.

  Further, in the small vessel, when the heat exchanger is attached (mounted) to the bottom surface of the water jet pump casing, the heat exchanger can be approached from the outside of the boat, that is, from the bottom surface side of the boat. The liquid can be easily exchanged.

  Further, in the small vessel, when a heat exchanging fin is protruded from a casing of a water jet pump to which the heat exchanger is attached (mounted), a heat exchanger having a higher heat exchanging capability can be easily realized. be able to.

  According to the small vessel according to the present invention, the “variation” of the temperature and the temperature distribution is unlikely to occur during start-up and continuous operation with the throttle fully open or close to it. Therefore, it becomes a small ship with low fuel consumption and oil consumption and low piston slap.

  Hereinafter, a small vessel according to an embodiment of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a schematic diagram conceptually showing a cooling structure for an engine of a small boat according to the first embodiment of the present invention, FIG. 7 is an overall side view of the small boat according to the embodiment of the present invention, and FIG. 7 is a plan view of FIG.

  7 and 8, A is a hull, and this hull A is composed of a hull H and a deck D covering the hull H. A connection line connecting the hull H and the deck D on the entire circumference is called a gunnel line G. In this embodiment, the Gunnel line G is located above the draft line L of the small vessel.

  As shown in FIG. 8, a substantially rectangular opening 16 is formed in the upper surface of the hull A in a plan view extending in the longitudinal direction slightly behind the center of the deck D, and is shown in FIGS. Thus, a seat S for riding is disposed above the opening 16.

The engine E is disposed in a space 20 having a “convex” cross section surrounded by the hull H and the deck D below the seat S.
In this embodiment, the engine E is a multi-cylinder (four cylinders in this embodiment) four-cycle engine E, and the crankshaft 26 of the engine E extends along the longitudinal direction of the hull A as shown in FIG. The output end of the crankshaft 26 is integrally rotatable to the pump shaft 21S side of the water jet pump P to which the impeller 21 is attached via the propeller shaft 27. It is connected. The outer periphery of the impeller 21 is covered with a pump casing 21 </ b> C, takes in water taken from a water inlet 17 provided on the bottom surface of the small ship through a water absorption passage, and is pressurized with a water jet pump P. -It is configured to obtain a propulsive force by accelerating and discharging from the rear end injection port 21K through the pump nozzle (spout part) 21R whose water passage cross-sectional area has become smaller as it goes backward.

  In FIG. 7, 21V is a stationary blade for rectifying water passing through the water jet pump P. 7 and 8, reference numeral 24 denotes a bar-type steering handle. By operating the handle 24 to the left and right, the steering wheel behind the pump nozzle 21 </ b> R is connected via a cable 25 indicated by a dashed line in FIG. 8. The nozzle 18 is swung left and right so that the boat can be steered in a desired direction when the water jet pump P is in operation.

  Further, as shown in FIG. 7, a bowl-shaped reverse deflector 19 is disposed above and behind the steering nozzle 18 so as to be swingable downward about a horizontally disposed swing shaft 19a. The deflector 19 is configured to swing backward to a lower position behind the steering nozzle 18 so that water discharged rearward from the steering nozzle 18 can be turned forward to move backward.

  7 and 8, reference numeral 22 denotes a rear deck. The rear deck 22 is provided with an openable / closable hatch cover 29, and a small-capacity storage box is formed below the hatch cover 29. 7 or 8, reference numeral 23 denotes a front hatch cover, and a box (not shown) for storing equipment and the like is provided below the hatch cover 23. In FIG. 8, Lt is a throttle lever for operating the engine speed, and Ep is an exhaust pipe for exhausting exhaust gas from the exhaust manifold Em side to the outside.

By the way, a small planing boat which is a small boat according to an embodiment of the present invention includes a cooling structure as shown in FIG. That means
As schematically shown in FIG. 1, the cooling jacket in the cylinder block Cb of the engine E is supplied to an oil pump Pm from an oil tank To provided separately from the engine E through an oil pipe P1. Therefore, the oil having a low temperature is pumped. Then, the oil whose temperature has been increased by cooling the cylinder block Cb is returned to the oil tank To via the oil pipe P2. The oil pipe P2 is provided with a thermostat type valve V that opens above a predetermined temperature.

  Further, to the cylinder head Ch of the engine E, low temperature water taken from the water jet pump P is supplied as cooling water from the water jet pump P for propulsion through the cooling passage in the exhaust manifold Em. The exhaust manifold Em and the cylinder head Ch are supplied and cooled. And the cooling water which cooled these exhaust manifold Em and cylinder head Ch is comprised so that it may be discharged | emitted out of a ship.

  Further, from the oil tank To, the oil pump P3 is used to feed the lubricated portion Ea of the engine E through the oil pipe P3, specifically, for example, a plurality of bearings of the crankshaft, a cylinder liner below the piston, and the like. The oil is configured to be lubricated. And the oil which lubricated the lubrication required part Ea of the engine E is comprised so that it may return to the said oil tank To via the oil pipe P4 by the scavenge pump Ps.

  The oil tank To is provided with a cooler (oil cooler) Co to which cooling water is supplied, and cools the cylinder block Cb of the engine E as described above. Ea is lubricated to cool the heated oil. Cooling water is supplied to the cooler Co from the water jet pump P described above, and the cooler Co can be cooled. In the case of this embodiment, the cooler Co is configured to be supplied with cooling water that is being sent to the cooling passage of the exhaust manifold Em described above. Such a configuration is a preferred embodiment in that less cooling water piping is required.

  Thus, in the case of a small planing boat having a cooling structure configured as described above, the operation is as follows. That is, when the engine E is started, the thermostat type valve V is “closed”, so that the cylinder block Cb quickly rises in temperature and rises to a predetermined temperature, for example, 90 ° C. The valve V is “open”, and low temperature oil is supplied from the oil tank To, and cooling of the cylinder block Cb is started by this oil. Further, the oil in the oil tank To is effectively cooled by the cooler Co.

  On the other hand, when the engine E is started, the exhaust manifold Em and the cylinder head Ch are immediately supplied with cooling water from the water jet pump P, and the exhaust manifold Em and cylinder are about to rise in temperature in a short time by the combustion gas. The head Ch is effectively cooled.

According to the present cooling structure that is cooled as described above, the cylinder block Cb portion of the engine E has a closed circuit (closed loop) type indirect cooling structure in which oil is used as a primary coolant, so that the engine is started. The temperature of each part of the engine E and the “variation” of each temperature distribution during the continuous operation with the time fully opened or close to the throttle are reduced.
Therefore, the deformation of the cylinder bore can be reduced, and as a result, the clearance between the piston and the cylinder can be made as small as possible. As a result, it becomes easy to reduce lubricating oil consumption or to take measures against piston wrap noise. In addition, the exhaust system parts such as the cylinder head Ch and the exhaust manifold Em of the engine E adopt an open-loop direct cooling structure using cooling water from the water jet pump P, and the cooling water used for cooling is outside the ship. Since it is configured to be discharged, it is possible to effectively cool the exhaust system such as the cylinder head Ch and the exhaust manifold Em, which has a large cooling capacity and whose temperature is higher than other parts.

(Embodiment 2)
In the embodiment (Embodiment 1), the cooler Co is arranged in the oil tank To to cool the oil as the primary coolant, but instead, it is shown in FIG. Thus, the oil cooler Co may be arranged in the middle of the oil pipe P3 that feeds oil from the oil tank To to the cooling jacket side of the cylinder block Cb of the engine E by the oil pump Pm. Specifically, as shown in FIGS. 5 and 6, the oil cooler Co is provided so as to be in contact with the outer peripheral wall of the water jet pump P, and the cooling capacity of the water jet pump P is used. It becomes an organic configuration with little waste. In addition, in the oil cooler Co, in order to increase the contact area, increase the residence time, and increase the cooling capacity, as shown in FIG. 5 and FIG. It is preferable to make the structure meander.
In such a case, if the oil cooler Co is disposed at the bottom of the water jet pump P, in the case of a small planing boat, the oil cooler Co can be easily moved out of the ship by removing the pump cover disposed on the bottom of the hull. It is exposed and becomes a preferable configuration for oil replacement or cooler Co inspection.
By the way, as shown in FIG. 2, in this embodiment, the oil to the lubrication required portion Ea of the engine E is not so high in temperature, so that the oil does not pass through the cooler Co. A closed circuit between the tank To and the engine E is circulated. Further, the cooling structure by the cooling water from the water jet pump P to the cylinder head Ch and the exhaust manifold Em is configured in the same manner as in the first embodiment. In FIG. 2, the same or corresponding components as those in FIG.

(Embodiment 3)
Further, as another embodiment (Embodiment 3), it may be configured as illustrated in FIG. That is, a permanent cooler fluid may be used as the primary coolant for the cylinder block Cb of the engine E. In such a case, only the cooling jacket of the cylinder block Cb becomes a cooling system that independently cools. In this case, the permanent cooler liquid is brought into contact with the outer peripheral wall of the water jet pump P as in the second embodiment. A configuration in which the cooling is performed by the cooler Co provided as described above is a configuration that effectively uses the cooling capacity of the water jet pump P. In this case as well, Embodiments 1 and 2 are provided in that the cooling system is provided with a pump Pm for circulating the permanent cooler liquid and a thermostat type valve V for turning on and off the circulation of the cooling liquid. It is the same as the case of. Further, the configuration of the cooler Co is configured as shown in FIGS. 5 and 6 as in the case of the embodiment.
As in the case of the first embodiment, the lubrication required part Ea of the engine E is supplied from the oil tank To by the feed pump Pf and returned from the engine E side to the oil tank To side by the scavenge pump Ps. Yes.
In addition, the cylinder head Ch and the exhaust manifold Em of the engine E are cooled by water supplied from the water jet pump P. The oil tank To is provided with a cooler Co configured to cool the water supplied from the water jet pump P by passing through the oil tank To. In FIG. 3, the same or corresponding components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

(Embodiment 4)
Further, as another embodiment (Embodiment 4), it may be configured as illustrated in FIG. That is, the cooling jacket of the cylinder block Cb of the engine E and the lubrication required portion Ea of the engine E are connected in series by the oil pipe P5, and from the oil tank To by the oil pipe P6 by the feed pump Pf, Low temperature oil is supplied to the cooling jacket of the cylinder block Cb, and then this oil is supplied to the lubrication required part Ea of the engine E. The oil that has finished cooling the lubrication required portion Ea of the engine E is returned to the oil tank To side by the scavenge pump Ps through the oil pipe P7.
In addition, the cylinder head Ch and the exhaust manifold Em of the engine E are configured to be cooled with cooling water from the water jet pump P. The cooling water is used to cool the oil passing through the oil pipe P7 by the cooler Co. In FIG. 4, the same or corresponding components as those in FIGS. 1 to 3 are denoted by the same reference numerals.

And also in the case of above-mentioned Embodiments 2-4, there exists an effect similar to the case of Embodiment 1. FIG. That is, the cylinder block Cb portion of the engine E has a closed circuit (closed loop) type indirect cooling structure in which oil (permanent cooler liquid in the embodiment shown in FIG. 3) is the primary cooling liquid. The temperature and the “variation” of each temperature distribution during start-up and during continuous operation with the throttle fully open or close thereto are reduced.
Therefore, the deformation of the cylinder bore can be reduced, and as a result, the clearance between the piston and the cylinder can be made as small as possible. Therefore, it is possible to reduce the consumption of lubricating oil or take measures against piston wrap noise. It becomes easy. Further, the exhaust system portion such as the cylinder head Ch and the exhaust manifold Em of the engine E adopts an open-loop direct cooling structure using cooling water from the water jet pump P, so that the cooling capacity is large. It is possible to effectively cool the exhaust system such as the cylinder head Ch and the exhaust manifold Em whose temperature is higher than the portion.

  The present invention can be used for small ships and the like.

It is the schematic diagram which showed notionally the cooling structure of the engine of the small ship concerning the 1st Embodiment of this invention. It is the schematic diagram which showed notionally the cooling structure of the engine of the small ship concerning the 2nd Embodiment of this invention. It is the schematic diagram which showed notionally the cooling structure of the engine of the small ship concerning the 3rd Embodiment of this invention. It is the schematic diagram which showed notionally the cooling structure of the engine of the small ship concerning the 4th Embodiment of this invention. It is a figure which shows the structure of the cooler attached to the water jet pump used for Embodiment 2 and 3, (a) is the figure cut in the cross-sectional direction of the water jet pump, (b) is Vb-Vb of (a). An arrow view, (c) is a Vc-Vc arrow view of (a). FIG. 5 is a diagram showing a configuration of a cooler attached to a water jet pump according to an embodiment different from FIG. 5 used in the second and third embodiments, and (a) is a cross-sectional view taken along the transverse direction of the water jet pump. (b) is a VIb-VIb arrow view of (a), (c) is a VIc-VIc arrow view of (a). 1 is an overall side view of a jet propulsion-type small vessel according to an embodiment of the present invention. It is a whole top view of the small ship shown in FIG.

Explanation of symbols

E …… Engine
Cb ...... Cylinder block
Ch …… Cylinder head
Em …… Exhaust manifold

Claims (8)

In small vessels configured to be propelled by a water jet pump driven by an engine,
A small vessel characterized in that the cylinder block portion of the engine has an indirect cooling structure and the exhaust system portion has a direct cooling structure.   2. A small vessel according to claim 1, wherein a cylinder head portion of the engine is directly cooled.   The small ship according to claim 1 or 2, wherein the primary cooling liquid of the indirect cooling structure is oil, and the oil is circulated in a closed circuit by an oil pump.   The small vessel according to claim 1 or 2, wherein the primary cooling liquid of the indirect cooling structure is cooling water, and the cooling water is circulated in a closed circuit by a cooling water circulation pump.   As the closed circuit, the engine lubrication circuit is used, supplied from the oil tank to the cylinder block via the feed pump, and then lubricated the required lubrication part of the engine, and the oil is supplied via the scavenge pump. 4. The small vessel according to claim 3, wherein the small vessel is configured to recirculate in the tank.   The small vessel is a jet propulsion type small vessel, and a heat exchanger is provided in a part of the closed circuit, and the heat exchanger is arranged to be mounted on a casing of a water jet pump for jet propulsion. The small ship according to any one of claims 3 to 5, wherein the small ship is provided.   The small ship according to claim 6, wherein the heat exchanger is attached to a bottom surface of a casing of a water jet pump. The small vessel according to claim 6 or 7, wherein fins for heat exchange protrude from a casing of a water jet pump to which the heat exchanger is attached.

Images