JP4840094B2 - engine - Google Patents

Description

  The present invention relates to an engine configured to recover mechanical energy from waste heat.

  As this type of engine, for example, those described in JP-A-6-88623, JP-A-2000-73753, and JP-A-2000-345835 are known. These engines are configured such that steam is generated from cooling water (cooling medium) by waste heat such as combustion heat and frictional heat, and mechanical energy can be recovered by expansion of the steam.

  These engines generally include a cylinder block, a supply pump, an inflow path, an outflow path, a heater (superheater), an expander (turbine), and a condenser.

  The cylinder block is provided with a water jacket that constitutes a part of the cooling water circulation path. The supply pump is configured to supply the cooling water to the water jacket via the inflow passage.

  The outflow passage communicates with the heater. This heater is configured to further heat (overheat) the steam flowing out of the water jacket using the heat of the exhaust gas as a heat source.

  The expander is configured to convert the expansion energy of superheated steam into mechanical energy. The condenser is configured to condense into a liquid by cooling the steam that has lost its energy and has become low pressure.

  In this configuration, the cooling water is supplied from the inflow path to the water jacket. Within the water jacket, steam is generated from the cooling water. The steam is further heated (overheated) by heat exchange with the exhaust gas by the heater.

Then, the heated (overheated) steam expands in the expander. Thereby, mechanical energy is recovered. Thereafter, the low-pressure steam that has lost its energy flows into the condenser and is condensed to become a liquid (the cooling water). The cooling water condensed by the condenser is supplied again to the water jacket by the supply pump.
JP-A-6-88623 JP 2000-73753 A JP 2000-345835 A

  In this type of engine, the cooling medium has two functions: (1) engine cooling to prevent overheating, and (2) mechanical energy recovery by absorbing and expanding waste heat. In this regard, the conventional engine of this type has room for improvement in the supply state of the cooling medium.

  For example, in the configurations described in JP-A-6-88623, JP-A-2000-73753, and JP-A-2000-345835, the cooling medium that has flowed into the water jacket is a wall surface of the water jacket. The cylinder block and the cylinder head are cooled, and the cooling medium is evaporated (steam is generated).

  In such a configuration, a film boiling phenomenon of the cooling medium often occurs on the wall surface of the water jacket. Due to this film boiling phenomenon, a thin layer is formed between the wall surface of the water jacket and the cooling medium by the vapor of the cooling medium. Since this thin gas layer acts as a heat insulating layer, the cooling efficiency of the cylinder block and the cylinder head is lowered, and at the same time, the heat absorption efficiency of the cooling medium is lowered. As this endothermic efficiency decreases, the mechanical energy recovery efficiency also decreases.

  That is, in this type of conventional engine, due to the film boiling phenomenon on the wall surface of the water jacket, (1) cooling of the engine to prevent overheating, and (2) recovery of mechanical energy by absorption and expansion of waste heat. For both of these functions, sufficient effects were not obtained.

  The present invention provides an engine excellent in both cooling efficiency and energy recovery efficiency.

Means for Solving the Problems and Effects of the Invention

  The engine of the present invention includes an engine block, a cooling medium injection unit, a steam outlet, a steam heater, an expander, and a condenser.

  The engine block is formed with a cylinder, an intake passage, and an exhaust passage. The intake passage and the exhaust passage communicate with the cylinder.

  The cooling medium injection unit is configured to inject a liquid cooling medium toward the engine block. One or more cooling medium injection units may be provided for each cylinder. The cooling medium ejecting unit may be constituted by, for example, a liquid ejecting device attached to the engine block. Alternatively, the cooling medium injection unit may be configured by a small-diameter nozzle at the end of the cooling medium passage provided in the engine block.

  The cooling medium injection unit may be configured to inject the cooling medium into droplets toward the engine block.

  In addition, the cooling medium injection unit may be configured to inject the liquid cooling medium to a part (the vicinity of the combustion chamber or the exhaust passage) of the engine block that has the highest temperature.

  The steam lead-out path is configured to lead out the steam of the cooling medium vaporized after being injected by the cooling medium injection unit to the outside of the engine block.

  The steam heater is interposed in the steam lead-out path. The steam heater is configured to heat the steam by heat exchange between the exhaust gas passing through the exhaust passage and the steam.

  The expander is interposed in the steam outlet path. The expander is configured to recover mechanical energy from the steam that has passed through the steam heater. A turbine may be used as the expander. Or the structure provided with the piston etc. may be used as said expander.

  The condenser is configured to condense the vapor that has passed through the expander.

  Here, the engine block includes a cylinder head and a cylinder block, and the cylinder head can be configured as follows.

  The cylinder head is formed with the intake passage and the exhaust passage. The cylinder block is formed with the cylinder and a water jacket.

  The water jacket is provided so as to surround the cylinder. The water jacket is formed so as to communicate with a space in the cylinder head where the cooling medium is ejected by the cooling medium ejecting section. The upper part in this space is connected to the steam outlet.

  An exhaust valve stem guide hole is formed in the cylinder head. The exhaust valve stem guide hole is a hole through which the exhaust valve stem passes. The exhaust valve stem is a rod-like member having an exhaust valve provided at the lower end. The exhaust valve is configured to be able to close the exhaust passage from the cylinder side.

  A stem seal member is attached to the cylinder head. The stem seal member is configured to seal a gap between the exhaust valve stem guide hole and the exhaust valve stem.

  In the engine of the present invention, the liquid coolant is injected into the engine block by the coolant injection unit. Thereby, the engine block is cooled. Further, the cooling medium absorbs heat as the engine block is cooled. As a result, steam of the cooling medium is generated.

  The steam is led out from the engine block via the steam lead-out path and reaches the steam heater. In this steam heater, the steam is heated (overheated) by heat exchange between the exhaust gas passing through the exhaust passage and the steam.

  The heated steam expands in the expander. Thereby, mechanical energy is recovered from the steam. The steam passing through the expander reaches the condenser. In this condenser, the steam is condensed. That is, the cooling medium becomes a liquid in the condenser. The cooling medium that has become liquid can be supplied again to the cooling medium ejection unit.

  According to the engine of the present invention, the liquid cooling medium is injected into the engine block. Thereby, generation | occurrence | production of the film boiling phenomenon in the wall surface in which the said cooling medium of the said engine block was injected can be relieve | moderated or suppressed.

  Therefore, the engine block can be efficiently cooled. At the same time, heat transfer from the engine block to the cooling medium, that is, heat absorption of the cooling medium can be performed efficiently. Therefore, the high energy steam can be generated efficiently.

  Thus, according to the present invention, both the cooling efficiency of the engine block and the energy recovery efficiency from the waste heat generated in the engine block can be made higher.

  -The cooling medium supply path which supplies the said cooling medium to the said cooling medium injection part may be formed in the said cylinder head so that the vicinity of the said stem seal member may be passed.

  In such a configuration, the liquid coolant is injected to the engine block by the coolant injection unit. At this time, the cooling medium supplied to the cooling medium injection unit passes through a portion of the cylinder head in the vicinity of the stem seal member. Then, the part is cooled by the liquid cooling medium.

  According to such a configuration, deterioration of the stem seal member due to heat can be suppressed.

  The cooling medium injection unit may be configured to inject the cooling medium in the vicinity of the stem seal member.

  In such a configuration, the cooling medium spraying unit ejects the liquid cooling medium in the vicinity of the stem seal member in the cylinder head. Then, the vicinity of the stem seal member in the cylinder head is cooled by the liquid cooling medium.

  According to such a configuration, deterioration of the stem seal member due to heat can be suppressed.

  The engine may further include a cooling medium storage unit and a cooling medium delivery pump. Here, the cooling medium storage unit is configured to store the liquid cooling medium condensed by the condenser. The cooling medium delivery pump is configured to deliver the liquid cooling medium from the cooling medium reservoir to the cooling medium ejection unit.

  In this configuration, the liquid cooling medium condensed in the condenser is stored in the cooling medium storage unit. The liquid cooling medium stored in the cooling medium storage part is sent out toward the cooling medium injection part by the cooling medium delivery pump.

  According to such a configuration, a sufficient amount of the liquid cooling medium is stored in the cooling medium storage unit, so that the supply of the liquid cooling medium to the cooling medium injection unit is stably performed. obtain.

  A supply pump and a circulation pump as the cooling medium delivery pump may be provided in the engine. Here, the supply pump is configured to deliver the cooling medium from the cooling medium reservoir to the water jacket. The circulation pump is configured to send the cooling medium from the bottom of the water jacket to the cooling medium injection unit.

  In this configuration, the liquid cooling medium is delivered from the cooling medium reservoir to the water jacket by the supply pump. Further, the liquid cooling medium is sent out from the bottom of the water jacket to the cooling medium injection section by the circulation pump.

  Here, the liquid cooling medium delivered to the cooling medium injection unit by the circulation pump was not vaporized (not vaporized) of those injected by the cooling medium injection unit. And that delivered from the cooling medium reservoir by the supply pump.

  That is, the liquid cooling medium that has been heated to some extent is sent to the cooling medium injection unit by the circulation pump, and is injected to the engine block by the cooling medium injection unit.

  With this configuration, excessive cooling of the engine block can be prevented. Therefore, the generation of friction loss can be effectively suppressed. Also, the temperature of the steam can be increased. Therefore, the energy recovery efficiency from the waste heat generated in the engine block can be further increased.

  The connection state between the bottom portion of the water jacket and the circulation pump is set so that only the liquid material from the liquid cooling medium and the vapor in the water jacket is supplied to the circulation pump. It is suitable.

  That is, it is preferable that the water jacket and the circulation pump are configured so that only the liquid can be extracted from the mixture of the liquid and the vapor and supplied to the cooling medium ejection unit. For example, at the lowest part of the water jacket, a liquid discharge passage for the cooling medium toward the circulation pump may be formed.

  Thereby, reliable injection of the liquid cooling medium by the cooling medium injection unit and appropriate and reliable cooling of the engine block can be achieved.

  In addition to the cooling medium injection unit connected to the circulation pump, the cooling medium injection unit connected to the supply pump may be provided. That is, the supply pump is configured to supply the cooling medium to the water jacket by injecting the liquid cooling medium to the engine block via another cooling medium injection unit. Also good.

  In this configuration, the liquid cooling medium supplied from the circulation pump is injected to the engine block by the cooling medium injection unit.

  Further, the liquid cooling medium supplied from the supply pump is injected into the engine block by another cooling medium injection unit. And the thing which was not vaporized (it did not turn into steam) among what was injected is supplied to the bottom of the water jacket, and is supplied to the circulation pump.

  According to this configuration, reliable injection of the liquid cooling medium into the engine block and proper and reliable cooling of the engine block can be achieved.

  The circulation pump may be configured to send the cooling medium also to a heater configured to heat a predetermined heating target.

  In such a configuration, the liquid cooling medium is sent from the bottom of the water jacket to the cooling medium injection unit and the heater by the circulation pump. That is, the liquid cooling medium that has been heated to some extent is sent out to the cooling medium injection section and the heater by the circulation pump. And this heater heats predetermined | prescribed warming object (air etc. in a driver's room).

  According to this configuration, the warming up of the heater can be performed at an early stage.

  The cooling medium injection unit may be configured to inject the cooling medium toward a steam discharge path that connects the engine block and the steam outlet path.

  In this case, the engine may be configured as follows: the engine block is arranged to be inclined to the first side with respect to the vertical direction. In addition, the cooling medium injection unit is provided on the first side of the engine block. Further, the steam discharge path is provided on the second side opposite to the first side, above the engine block.

  In such a configuration, the liquid coolant is injected to the engine block by the coolant injection unit. The steam of the cooling medium generated by absorbing heat from the engine block flows into the steam outlet path through the steam discharge path.

  At this time, the liquid cooling medium is injected toward the vapor discharge path by the cooling medium injection unit. As a result, an air flow is formed from the cooling medium injection section toward the steam discharge path. By this flow, the steam is introduced into the steam outlet path via the steam discharge path.

  According to such a configuration, the generated steam can be efficiently introduced into the heating unit.

  Hereinafter, embodiments of the present invention (embodiments that the applicant considers best at the time of filing of the present application) will be described with reference to the drawings.

<Engine block configuration>
FIG. 1 is a schematic configuration diagram of an engine 100 according to an embodiment of the present invention. The engine 100 in the present embodiment is configured as an in-line multi-cylinder gasoline engine.

  Referring to FIG. 1, the engine 100 includes an engine block 110. The engine block 110 is a member that constitutes the main body of the engine 100. FIG. 1 shows a side sectional view of the engine block 110 perpendicular to the cylinder arrangement direction.

<< Cylinder block configuration >>
The engine block 110 includes a cylinder block 120. The cylinder block 120 is formed with a cylinder 121 that is a substantially cylindrical through hole. A piston 122 is accommodated in the cylinder 121 so as to be capable of reciprocating along the height direction (vertical direction in the drawing) of the cylinder 121.

  That is, FIG. 1 shows a side sectional view of the engine block 110 by a plane passing through the axial center of one cylinder 121. The engine 100 of the present embodiment is assumed to have the following configuration corresponding to all the cylinders 121.

  The cylinder block 120 is formed with a lower jacket 123 as a water jacket of the present invention. The lower jacket 123 is provided so as to surround the cylinder 121. The lower jacket 123 is a substantially ring-shaped space in plan view. The lower jacket 123 is configured so that the cooling water and the steam can pass therethrough.

  A cooling water discharge path 124 is provided at the lowest part of the lower jacket 123. The cooling water discharge path 124 is configured so that liquid cooling water stored at the bottom of the lower jacket 123 can be discharged to the outside. That is, the cooling water discharge path 124 is configured so that only the liquid liquid at the bottom of the cooling water in the lower jacket 123 can be discharged to the outside.

  A cooling water injection path 125 is provided at the bottom of the lower jacket 123. The cooling water injection path 125 is configured such that liquid cooling water can be injected into the bottom of the lower jacket 123. The cooling water injection path 125 is provided above the cooling water discharge path 124 so that a predetermined amount of cooling water can be stored in the lower jacket 123.

<< Cylinder head configuration >>
The engine block 110 includes a cylinder head 130. The lower end surface of the cylinder head 130 is joined to the upper end surface of the cylinder block 120.

  The cylinder head 130 is formed with an intake port 131 constituting the intake passage of the present invention and an exhaust port 132 constituting the exhaust passage of the present invention. The intake port 131 and the exhaust port 132 are provided so as to communicate with the upper end portion of the cylinder 121.

  In the present embodiment, two intake ports 131 are provided along the cylinder arrangement direction. The pair of intake ports 131 are formed substantially symmetrically across a plane passing through the axial center of the cylinder 121. Similarly, two exhaust ports 132 are provided along the cylinder arrangement direction.

  A spark plug 133 is provided between the intake port 131 and the exhaust port 132. The spark plug 133 is disposed near the axial center of the cylinder 121.

  FIG. 2A is an enlarged view of the cylinder head 130 shown in FIG. FIG. 2A is a side sectional view of the cylinder head 130 shown in FIG. 1 by a plane passing through the axial center of the cylinder 121 and perpendicular to the cylinder arrangement direction. 2B is a side cross-sectional view of the cylinder head 130 shown in FIG. 1 in a plane different from FIG. 2A. That is, FIG. 2B is a side cross-sectional view of the cylinder head 130 shown in FIG.

  Referring to FIG. 1, FIG. 2A, and FIG. 2B, the cylinder head 130 is provided with an intake portion 134. The intake section 134 is configured as follows so that the gas before combustion can be introduced into the cylinder 121 (combustion chamber).

  The intake part 134 includes an intake valve 134a. The intake valve 134a is configured to be able to close the intake port 131 from the cylinder 121 side (from the piston 122 side).

  The intake valve 134a is provided at the lower end of the intake valve stem 134b. The intake valve stem 134b is a rod-like member and is formed integrally with the intake valve 134a.

  The intake valve stem 134b is disposed so as to penetrate the intake valve stem guide hole 134c. The intake valve stem guide hole 134 c is a through hole formed in the cylinder head 130. The intake valve stem guide hole 134c is configured to guide the vertical movement of the intake valve stem 134b.

  An intake valve stem seal member 134d is mounted at a position corresponding to the gap between the intake valve stem 134b and the intake valve stem guide hole 134c. The intake valve stem seal member 134d is configured to seal the gap described above.

  The cylinder head 130 is provided with an exhaust part 135. The exhaust part 135 is provided at a position substantially symmetrical to the intake part 134 with a plane passing through the axial center of the cylinder 121 and parallel to the cylinder arrangement direction. The exhaust part 135 is configured so that the burned gas in the cylinder 121 (combustion chamber) can be discharged out of the cylinder 121. The exhaust part 135 has the same structure as the intake part 134, and is configured as follows.

  The exhaust valve 135a is configured to be able to close the exhaust port 132 from the cylinder 121 side (from the piston 122 side). The exhaust valve 135a is provided at the lower end of a rod-shaped exhaust valve stem 135b. The exhaust valve stem 135b is formed integrally with the exhaust valve 135a.

  The exhaust valve stem 135b is disposed so as to penetrate the exhaust valve stem guide hole 135c. The exhaust valve stem guide hole 135 c is a through hole formed in the cylinder head 130. The exhaust valve stem guide hole 135c is configured to guide the vertical movement of the exhaust valve stem 135b.

  Further, an exhaust valve stem seal member 135d is mounted at a position corresponding to the gap between the exhaust valve stem 135b and the exhaust valve stem guide hole 135c. The exhaust valve stem seal member 135d is formed of a synthetic resin having heat resistance. The exhaust valve stem seal member 135d is configured to seal the gap described above.

<<< Configuration around the cooling water injection section >>>
An upper jacket 136 is formed inside and below the cylinder head 130. The upper jacket 136 is a space configured to allow liquid cooling water and its vapor to pass therethrough. The upper jacket 136 is provided between the pair of intake ports 131, between the pair of exhaust ports 132, and between the intake port 131 and the exhaust port 132.

  The upper jacket 136 is provided so as to communicate with the upper end portion of the lower jacket 123. That is, the liquid cooling water can flow down from the upper jacket 136 to the lower jacket 123 by the action of gravity. Further, the steam of the cooling water generated in the lower jacket 123 can flow into the upper jacket 136 above it.

  A cooling water injection unit 137 is provided at a position corresponding to the upper jacket 136 provided between the pair of exhaust ports 132. The cooling water injection unit 137 is configured and arranged so that liquid cooling water can be injected toward the inner wall surface of the cylinder head 130.

  Specifically, in the present embodiment, the cooling water injection unit 137 is configured and arranged so that it can be injected toward a position on the inner wall surface of the upper jacket 136 and in the vicinity of the exhaust valve 135a. The cooling water injection unit 137 has the same structure as the fuel injection nozzle, and is configured so that the cooling water can be jetted vigorously in the form of fine droplets.

  A cooling water supply path 138 is provided inside the cylinder head 130. The cooling water supply path 138 is configured to be able to supply liquid cooling water to the cooling water injection unit 137. The cooling water supply path 138 includes an internal passage 138a and a connection passage 138b.

  The internal passage 138 a is a cooling water passage formed inside the wall material that constitutes the main body of the cylinder head 130. The internal passage 138a is provided so as to pass in the vicinity of the exhaust valve stem seal member 135d. The connection passage 138b is composed of a piping member that connects the end of the internal passage 138a and the cooling water injection unit 137.

  A steam discharge path 139 is formed in the upper part of the cylinder head 130. Specifically, the steam discharge path 139 is provided so as to extend obliquely upward from the uppermost portion of the upper jacket 136. The steam discharge path 139 is connected to the uppermost part of the upper jacket 136. The steam discharge path 139 is configured to discharge the steam in the upper jacket 136 to the outside of the upper jacket 136.

<Configuration of waste heat recovery unit>
Referring to FIG. 1 again, the engine 100 includes a waste heat recovery unit 140. The waste heat recovery unit 140 is configured as follows so that mechanical energy can be recovered from the waste heat generated in the engine block 110.

  A steam outlet path 141 is connected to the steam discharge path 139. The steam lead-out path 141 is configured to be able to lead out the steam of the cooling water vaporized after being injected by the cooling water injection unit 137 to the outside of the engine block 110. That is, the uppermost part of the upper jacket 136 is connected to the steam outlet path 141 through the steam discharge path 139.

  A superheater 142, a turbine 143, and a condenser 144 are interposed in the steam outlet path 141.

  The superheater 142 as a steam heater according to the present invention is connected to an exhaust passage that is a passage for exhaust gas discharged from the exhaust port 132. The superheater 142 is configured to heat the steam by heat exchange between the exhaust gas and the steam. That is, the superheater 142 is configured to be able to generate superheated steam by heating the steam discharged from the steam discharge path 139 with the exhaust gas.

  The turbine 143 as an expander of the present invention is configured to recover mechanical energy from superheated steam generated via the superheater 142. In other words, the turbine 143 includes rotating blades, and the rotating blades are configured to rotate by the expansion of superheated steam introduced from the superheater 142.

  The condenser 144 is configured to be able to condense by cooling the steam that has passed through the turbine 143 by heat exchange with the outside air. The capacitor 144 has a structure similar to that of the radiator.

  The capacitor 144 is connected to a catch tank 145 as a cooling medium storage unit of the present invention. The catch tank 145 is configured to store an amount of cooling water that can satisfy both the lower jacket 123 and the upper jacket 136.

  A cooling water recovery port 145 a as a cooling water inlet is provided at the upper end of the catch tank 145. The cooling water recovery port 145a is configured to be able to introduce liquid cooling water obtained by the condenser 144 into the catch tank 145. The catch tank 145 is provided with a lower cooling water supply port 145b and an upper cooling water supply port 145c as cooling water outlets.

  The lower cooling water supply port 145b is configured to discharge the cooling water from the lowest part of the catch tank 145 to the outside. The upper cooling water supply port 145c is provided above the catch tank 145 and below the cooling water recovery port 145a. The upper cooling water supply port 145c is configured so that cooling water can be discharged from the upper portion of the catch tank 145 to the outside.

  The lower cooling water supply port 145b and the upper cooling water supply port 145c are respectively connected to the first and second inflow ports of the control valve 146 formed of a three-way valve. The outflow side port of the control valve 146 is connected to the supply pump 147.

  The supply pump 147 as the cooling medium delivery pump of the present invention is connected to a cooling water injection path 125 provided at the bottom of the lower jacket 123. The supply pump 147 is configured to be able to send liquid cooling water from the catch tank 145 to the bottom of the lower jacket 123.

<Configuration of hot water circulation section>
The engine 100 includes a hot water circulation unit 150. The hot water circulation unit 150 is configured as follows so as to form a (relatively high temperature) cooling water circulation path starting from the lower jacket 123.

  The hot water circulation unit 150 includes a circulation pump 151 as a cooling medium delivery pump of the present invention. An inflow port of the circulation pump 151 is connected to the cooling water discharge path 124. The outflow side port of the circulation pump 151 is connected to an internal passage 138a in the cooling water supply passage 138 via a water jet circulation passage 152 which is a cooling water passage.

  In other words, from the bottom of the lower jacket 123, the liquid pump returns to the bottom of the lower jacket 123 through the circulation pump 151, the water jet circulation path 152, the cooling water supply path 138, the cooling water injection section 137, and the upper jacket 136. A cooling water circulation path is formed.

  A heater 154 is interposed in a heater circulation path 153 that is a cooling water path branched from the water jet circulation path 152. The heater circulation path 153 is provided downstream of the heater 154 so as to merge with the cooling water discharge path 124. The heater 154 in the present embodiment is configured to heat the air in the automobile interior.

  That is, in the present embodiment, the circulation pump 151 is configured to send liquid cooling water from the lowest portion of the lower jacket 123 to the cooling water injection unit 137 and the heater 154.

<Operation of Engine of Embodiment>
Hereinafter, the operation of the engine 100 of the present embodiment having the above-described configuration will be described with reference to the drawings.

  Referring to FIG. 1, when the engine 100 is started, a relatively small amount of liquid cooling water (much smaller than the capacity of the lower jacket 123) is stored at the bottom of the lower jacket 123.

  After engine 100 is started, circulation pump 151 is started. Then, the liquid cooling water at the bottom of the lower jacket 123 is sent to the water jet circulation path 152 and the heater circulation path 153.

  The liquid cooling water sent to the water jet circulation path 152 passes through the internal passage 138 a in the cooling water supply path 138. Thereby, a portion of the cylinder head 130 in the vicinity of the exhaust valve stem seal member 135d is cooled. In other words, the liquid coolant is heated by the portion of the cylinder head 130 near the exhaust valve stem seal member 135d.

  Then, the liquid cooling water that has passed through the internal passage 138 a in the cooling water supply passage 138 reaches the cooling water injection unit 137. Then, the cooling water injection unit 137 jets the liquid cooling water vigorously toward the inner wall surface of the cylinder head 130. That is, droplet-shaped cooling water is jetted onto the inner wall surface of the upper jacket 136 and in the vicinity of the exhaust valve 135a. Thereby, the upper jacket 136 is cooled. In other words, the droplet-shaped cooling water is further heated by the heat absorption from the upper jacket 136.

  A part of the heated droplet-like cooling water becomes saturated steam, and is led out from the upper jacket 136 to the steam outlet path 141 through the steam discharge path 139. The cooling water that has been heated without being vaporized is returned to the lower jacket 123 below. Even in the middle from the upper jacket 136 toward the bottom of the lower jacket 123, the liquid cooling water can be transformed into steam due to heat absorption from the cylinder block 120. The steam reaches the upper jacket 136 and is led to the steam lead-out path 141.

  The steam led out from the upper jacket 136 to the outside of the cylinder head 130 is heated by the heat exchange with the exhaust gas in the superheater 142 to become superheated steam. The superheated steam generated in the superheater 142 rotates the rotating blades by expansion in the turbine 143. As a result, the thermal energy of the superheated steam is converted into the movement (rotation) energy of the rotating blades of the turbine 143. That is, mechanical energy is recovered from the superheated steam.

  The steam that has become low energy through the turbine 143 is condensed by being cooled by the condenser 144. The cooling water that has become liquid in the condenser 144 is recovered in the upper part of the catch tank 145 through the cooling water recovery port 145a.

  On the other hand, the liquid cooling water sent to the heater circulation path 153 by the circulation pump 151 returns to the circulation pump 151 again via the heater 154.

  Liquid cooling water is supplied from the catch tank 145 to the bottom of the lower jacket 123 by a supply pump 147.

  Here, during operation at low and medium loads, the control valve 146 connects the upper cooling water supply port 145c and the supply pump 147, and the lower cooling water supply port 145b and the supply pump 147 are connected. Blocked. As a result, the relatively high temperature cooling water in the upper part of the catch tank 145 is supplied to the lower jacket 123. In addition, the amount of liquid cooling water supplied to the lower jacket 123 is limited. Therefore, excessive cooling of the engine block 110 can be effectively prevented.

  On the other hand, during high load operation, the control valve 146 connects the lower cooling water supply port 145b and the supply pump 147, and disconnects the connection between the upper cooling water supply port 145c and the supply pump 147. Thereby, the relatively low-temperature cooling water at the bottom of the catch tank 145 is supplied to the lower jacket 123. In addition, a relatively large amount of liquid cooling water is supplied to the lower jacket 123. Therefore, the engine block 110 is cooled well.

<Effects of Configuration of Embodiment>
Hereinafter, effects of the configuration of the present embodiment as described above will be described.

  In the configuration of the present embodiment, the liquid cooling water is jetted vigorously onto the inner wall surface of the engine block 110, that is, the inner wall surface of the upper jacket 136, by the cooling water injection unit 137. That is, the liquid cooling water collides with the inner wall surface of the upper jacket 136 vigorously.

  Thereby, the bubble by the vapor | steam of the cooling water adhering to the inner wall surface of the upper jacket 136 is blown off favorably. Therefore, even when the cylinder head 130 (particularly in the vicinity of the exhaust port 132) becomes hot due to high load operation or the like and a large amount of bubbles are generated on the inner wall surface of the upper jacket 136, the film boiling phenomenon occurs. Can be mitigated or suppressed.

  Therefore, according to such a configuration, the cylinder head 130 (especially in the vicinity of the exhaust port 132) is cooled well.

  Further, the temperature of the cooling water is efficiently increased by the waste heat generated in the cylinder head 130. Therefore, the recovery efficiency of mechanical energy from waste heat becomes good.

  In the present embodiment, liquid cooling water is injected into the vicinity of the combustion chamber and the exhaust port 132, which is the hottest part of the engine block 110.

  According to such a configuration, the engine block 110 can be efficiently cooled by cooling the part well. Moreover, energy recovery efficiency from waste heat can be improved by obtaining higher temperature steam.

  In the configuration of the present embodiment, the cooling water jet unit 137 jets fine droplet-shaped cooling water onto the inner wall surface of the upper jacket 136.

  Thereby, the cooling efficiency in the inner wall surface of the upper jacket 136 and the vaporization efficiency of cooling water can be improved. Therefore, the cylinder head 130 (especially in the vicinity of the exhaust port 132) is cooled well. Further, generation of steam for waste heat recovery can be performed stably.

  In the configuration of the present embodiment, when the engine 100 is started, a relatively small amount of cooling water (much smaller than the capacity of the lower jacket 123) is stored at the bottom of the lower jacket 123, and the upper side of the lower jacket 123 is stored. Most of the water has no cooling water.

  Thereby, the warm-up property of the engine block 110 (especially the cylinder block 120) becomes favorable. Therefore, the friction loss in the engine block 110 (particularly the cylinder block 120) can be effectively reduced.

  In the configuration of the present embodiment, the upper end portion of the lower jacket 123 provided so as to surround the cylinder 121 and the upper jacket 136 (liquid cooling water is injected by the cooling water injection portion 137 in the cylinder head 130). The lower end of (space) communicates. The steam discharge path 139 is provided so that steam can be discharged from the uppermost part of the upper jacket 136.

  Therefore, the steam of the cooling water is sent toward the superheater 142 and the turbine 143 from the steam discharge path 139 provided at the uppermost part of the upper jacket 136. Further, the steam generated in the lower lower jacket 123 can also flow into the upper jacket 136 and be sent from the steam discharge path 139 toward the superheater 142 and the turbine 143.

  On the other hand, the liquid cooling water sprayed by the upper upper jacket 136 that has not been vaporized (not vaporized) can flow down to the lower lower jacket 123.

  Thus, according to the configuration of the present embodiment, the vapor separation and the liquid separation in the upper jacket 136 are favorably performed. Therefore, the inflow of liquid cooling water to the superheater 142 and the turbine 143 can be effectively suppressed. Therefore, a decrease in operating efficiency of the waste heat recovery unit 140 can be suppressed as much as possible.

  In the configuration of the present embodiment, liquid cooling water is led out from the lowest part of the lower jacket 123 via the cooling water discharge passage 124 and supplied to the cooling water injection unit 137. That is, in the present embodiment, the liquid cooling water and the steam are separated by the cooling water discharge passage 124 provided at the lowest part of the lower jacket 123. Then, the separated liquid cooling water is supplied to the cooling water injection unit 137.

  Thereby, reliable injection of liquid cooling water by the cooling water injection unit 137 and appropriate and reliable cooling of the engine block 110 can be achieved.

  In the configuration of the present embodiment, the internal passage 138a for supplying liquid cooling water to the cooling water injection unit 137 passes through the vicinity of the exhaust valve stem seal member 135d.

  Thereby, the part of the cylinder head 130 in the vicinity of the exhaust valve stem seal member 135d is satisfactorily cooled by the liquid cooling water. Therefore, deterioration of the exhaust valve stem seal member 135d due to heat can be suppressed.

  In the configuration of the present embodiment, liquid cooling water condensed by the condenser 144 is stored in the catch tank 145. In addition, liquid cooling water is sent to the bottom of the lower jacket 123 by a supply pump 147 from a catch tank 145 that stores a sufficiently large amount of liquid cooling water. Then, the liquid cooling water once stored at the bottom of the lower jacket 123 is sent to the cooling water injection unit 137 and the heater 154 by the circulation pump 151.

  Thereby, supply of the liquid cooling water to the cooling water injection part 137 can be performed stably.

  Here, the cooling water at the bottom of the lower jacket 123 is heated to some extent by heat absorption from the engine block 110.

  Therefore, excessive cooling of the engine block 110 can be prevented. Also, the temperature of the steam generated in the upper jacket 136 can be made relatively high. Thereby, the energy recovery efficiency from waste heat can further improve. Further, relatively high-temperature cooling water is supplied to the heater 154 at an early stage. Thereby, the warm-up property of the heater 154 is improved.

<List of examples of modification>
Note that, as described above, the above-described embodiments are merely examples of typical embodiments of the present invention that the applicant has considered to be the best at the time of filing of the present application. Therefore, the present invention is not limited to the above-described embodiment. Therefore, it goes without saying that various modifications can be made to the above-described embodiment within the scope not changing the essential part of the present invention.

  Hereinafter, some typical modifications will be exemplified. In the following description of modifications, members having the same configuration and function as those described in the above-described embodiment are denoted by the same reference numerals as those in the above-described embodiment. Moreover, within the range which is not technically contradictory, description in the above-mentioned embodiment shall be used.

  However, it goes without saying that the modifications are not limited to those listed below. In addition, a plurality of modified examples can be applied in a composite manner as appropriate within a technically consistent range.

  The present invention (especially those expressed functionally and functionally in the constituent elements constituting the means for solving the problems of the present invention) is based on the above-described embodiment and the description of the following modifications. Should not be interpreted as limited. Such a limited interpretation is unacceptable and improper for imitators, while improperly harming the applicant's interests (rushing to file under a prior application principle).

  (A) The application target of the present invention is not limited to an inline engine. For example, the present invention can be suitably applied to any of V type, W type, and horizontally opposed type.

  Moreover, the application object of this invention is not limited to a gasoline engine. For example, the present invention can be applied to a diesel engine.

  (B) In the present invention, the number of valves is not limited. That is, the number of intake ports 131 and exhaust ports 132 is not limited.

  (C) Instead of the spark plug 133, a fuel injection valve may be provided. In this case, it can be either a gasoline engine or a diesel engine.

  (D) The rotational energy of the rotary blades provided in the turbine 143 may be converted into electricity, or may be used as a power source for other rotational drive systems.

  Further, instead of the turbine 143, a mechanism including a piston may be used.

  (E) There is no limitation on the driving method of the supply pump 147.

  For example, supply pump 147 may be configured to receive a driving force generated at the output shaft of engine 100 via a power transmission mechanism.

  Alternatively, the supply pump 147 may be configured to receive the driving force generated by the rotating blades of the turbine 143 via a power transmission mechanism.

  Alternatively, the supply pump 147 may be configured to be rotationally driven by an electric motor. Needless to say, the drive power of the electric motor may be electric energy recovered through the turbine 143.

  (F) The heater circulation path 153 may be provided so as to return to the lower jacket 123 via the heater 154.

  (G) FIG. 3 is a schematic configuration diagram of one modified example of the engine 100 shown in FIG.

  As shown in FIG. 3, separately from the catch tank 145, a cooling water tank 155 that can store liquid cooling water may be provided. The cooling water tank 155 is connected to the inflow side port of the circulation pump 151 of the circulation pump 151 by a water jet circulation path 152. The cooling water tank 155 is connected to the end of the heater circulation path 153. The cooling water tank 155 is connected to the outflow side port of the supply pump 147.

  In such a modification, liquid cooling water stored in the catch tank 145 is supplied from the catch tank 145 to the cooling water tank 155 by the supply pump 147.

  Further, liquid cooling water flows into the cooling water tank 155 from the bottom of the lower jacket 123. The cooling water flowing into the cooling water tank 155 from the bottom of the lower jacket 123 includes those stored at the bottom of the lower jacket 123 since the start of the engine 100 and the cooling water injected by the cooling water injection unit 137. And those that did not vaporize.

  According to this configuration, the supply of liquid cooling water to the cooling water injection unit 137 can be performed more stably.

  (H) FIG. 4 is a side sectional view showing the configuration of one modification of the cylinder head 130 shown in FIG.

  As shown in FIG. 4, the cooling water injection portion 137 in this modification is configured by a small-diameter nozzle at the end of the cooling water passage formed inside the wall material constituting the main body of the cylinder head 130. Yes. Also, the connection passage 138b is formed as a cooling water passage formed inside the wall material, similarly to the internal passage 138a. These coolant injection part 137 and connection passage 138b are also provided so as to pass in the vicinity of the exhaust valve stem seal member 135d.

  According to such a configuration, the portion of the cylinder head 130 in the vicinity of the exhaust valve stem seal member 135d is more satisfactorily cooled by the liquid cooling water. Therefore, deterioration of the exhaust valve stem seal member 135d due to heat can be suppressed.

  (I) FIG. 5 is a side sectional view showing the configuration of another modification of the cylinder head 130 shown in FIG.

  As shown in FIG. 5, in the configuration of this modified example, the cooling water injection unit 137 injects the cooling water in the vicinity of the exhaust valve stem seal member 135d and in the vicinity of the start end of the exhaust port 132. It is configured.

  In such a configuration, liquid cooling water is injected into a portion of the cylinder head 130 near the exhaust valve stem seal member 135d. Thereby, the said part is favorably cooled with liquid cooling water.

  Therefore, deterioration of the exhaust valve stem seal member 135d due to heat can be suppressed. Further, by obtaining higher temperature steam, the energy recovery efficiency from waste heat can be further improved.

  (J) FIG. 6 is a schematic configuration diagram of another modification of engine 100 shown in FIG.

  Referring to FIG. 6, in this modification, in addition to the cooling water injection unit 137 connected to the circulation pump 151, another cooling water injection unit 137 'is provided.

  The coolant injection unit 137 has the same structure as the fuel injection nozzle, as in the above-described embodiment. The cooling water injection portion 137 is an inner wall surface of the upper jacket 136 and supplies liquid cooling water to a position near the end portion of the intake port 131 and the start end portion of the exhaust port 132 (that is, near the combustion chamber). Constructed and arranged to inject.

  On the other hand, the cooling water injection portion 137 ′ is configured by a small-diameter nozzle at the end of the cooling water passage formed inside the wall material constituting the main body of the cylinder head 130, as in the above-described modification. The cooling water injection unit 137 ′ is configured and arranged to inject liquid cooling water to a portion of the cylinder head 130 in the vicinity of the exhaust valve stem seal member 135 d. That is, the supply pump 147 is configured to supply cooling water to the lower jacket 123 by injecting liquid cooling water to the cylinder head 130 via the cooling water injection unit 137 ′.

  And the outflow side port of the supply pump 147 is connected with the cooling water injection part 137 '. That is, in this modification, the supply pump 147 is configured to supply liquid cooling water to the cooling water injection unit 137 ′.

  In such a configuration, the liquid cooling water supplied from the circulation pump 151 is injected to the inner wall surface of the upper jacket 136 by the cooling water injection unit 137. As a result, the highest temperature portion of the cylinder head 130 is satisfactorily cooled, and high temperature steam is generated.

  Further, the liquid cooling water supplied from the supply pump 147 is injected by the cooling water injection unit 137 ′ into a portion of the cylinder head 130 near the exhaust valve stem seal member 135 d. Thereby, the said part is cooled favorably and high temperature steam is generated.

  Of the liquid cooling water jetted by the cooling water jetting units 137 and 137 ′, the liquid cooling water that has not been vaporized (not turned into steam) is supplied to the bottom of the lower lower jacket 123, and is supplied to the circulation pump 151. Will be supplied again.

  According to such a configuration, reliable injection of liquid coolant into the engine block 110 and proper and reliable cooling of the engine block 110 can be achieved.

  (K) The cooling water injection unit 137 and the cooling water injection unit 137 ′ in FIG. 6 may be configured to have the same structure. That is, the cooling water injection units 137 and 137 'can be configured in the same structure as the fuel injection nozzle. Alternatively, the cooling water injection units 137 and 137 ′ may be configured by a small-diameter nozzle at the end of the cooling water channel formed inside the wall material that constitutes the main body of the cylinder head 130.

  (L) In the configuration shown in FIG. 6, the cooling water tank 155 shown in FIG. 3 may be provided. In this case, a three-way valve is provided on the downstream side of the supply pump 147 so that the supply destination of the liquid cooling water by the supply pump 147 can be switched to either the cooling water injection unit 137 ′ or the cooling water tank 155. Also good.

  (M) FIG. 7 is a schematic configuration diagram of another modification of engine 100 shown in FIG.

  Referring to FIG. 7, in this modified example, the hot water circulation unit 150 and the cooling water injection unit 137 interposed in the hot water circulation unit 150 in FIG. 6 are omitted.

  That is, in this modified example, the liquid cooling water stored in the catch tank 145 is directly supplied to the cooling water injection unit 137 ′ via the supply pump 147.

  In this case, as shown in FIG. 7, it is preferable that the cylindrical felt member 161 is provided so as to be in contact with the inner wall surface of the lower jacket 123 on the side close to the cylinder 121. The felt member 161 is made of a fiber such as a glass fiber, and is configured so that liquid cooling water can be moved upward by surface tension (capillary phenomenon).

  In such a configuration, the liquid cooling water jetted by the cooling water jetting unit 137 ′ that has not been vaporized (does not become steam) flows down to the lower lower jacket 123. The liquid cooling water that has flowed into the lower jacket 123 penetrates the felt member 161 and rises toward the upper upper jacket 136. Then, the cooling water can become steam at the upper end (near the combustion chamber), which is the highest temperature portion in the cylinder 121. The steam flows into the upper jacket 136, is led to the outside through the steam discharge path 139 together with the steam generated in the upper jacket 136, and is introduced into the superheater 142 and the turbine 143.

  According to this configuration, the cylinder block 120 is appropriately cooled by the liquid cooling water that has flowed into the lower jacket 123. Further, steam can be efficiently generated from the liquid cooling water flowing into the lower jacket 123.

  (N) FIG. 8 is a schematic configuration diagram of another modification of the engine block 110 shown in FIG.

  Referring to FIG. 8, the engine block 110 is disposed so as to incline to the first side (left side in the figure) with respect to the vertical direction. The cooling water injection portions 137 and 137 ″ are provided on the first side of the engine block 110. The steam discharge passage 139 is provided on the first side of the cylinder head 130. It is provided on the second side (right side in the figure) opposite to.

  The coolant injection unit 137 is attached to the cylinder head 130. The cooling water injection unit 137 is configured and arranged so that liquid cooling water can be injected toward the start end of the exhaust port 132.

  An internal injection passage 126 is formed in the cylinder block 120. The internal injection passage 126 is a cooling water passage from the first side toward the steam discharge passage 139 in the upper part of the cylinder block 120. The internal injection passage 126 is provided perpendicular to the cylinder arrangement direction so as to extend obliquely upward.

  The cylinder block 120 and the cylinder head 130 are joined via a gasket 170.

  FIG. 9 is a plan view of the gasket 170 shown in FIG. FIG. 10 is a schematic configuration diagram of the engine block 110 of the modified example shown in FIG. 8 as viewed from above.

  Referring to FIG. 9, a communication hole 171 and an injection hole 172 are formed in the gasket 170.

  Referring to FIGS. 8 and 9, the communication hole 171 is provided at a position corresponding to the cylinder 121. The communication hole 171 is formed so that the upper jacket 136 and the lower jacket 123 communicate with each other along the (oblique) vertical direction.

  The injection hole 172 is provided between the adjacent cylinders 121 at a position corresponding to the end of the internal injection passage 126. Referring to FIG. 8, the internal injection passage 126 is provided so that the end thereof opens at the bottom of the upper jacket 136.

  Referring to FIG. 8, a cooling water injection unit 137 ″ is attached to the end portion on the first side of the internal injection passage 126. The cooling water injection unit 137 ″ is directed toward the steam discharge path 139. The cooling water can be injected.

  In such a configuration, liquid cooling water is injected onto the inner wall surface of the engine block 110 by the cooling water injection unit 137 and the cooling water injection unit 137 ″, and is generated by absorbing heat from the engine block 110. The steam of the cooled cooling water flows into the steam outlet path 141 through the steam discharge path 139.

  At this time, liquid cooling water is injected in the direction toward the steam discharge path 139 by the cooling water injection unit 137 and the cooling water injection unit 137 ″. Thereby, the cooling water injection unit 137 and the cooling water injection unit 137. ”Toward the steam discharge path 139, an air flow is formed. The steam of the cooling water generated in the engine block 110 is efficiently led to the steam lead-out path 141 by riding on this air flow.

  (O) In addition, in the elements constituting the means for solving the problems of the present invention, the elements expressed in terms of function and function are the specific structures disclosed in the above-described embodiments and modifications. In addition, any structure capable of realizing the operation / function is included.

1 is a schematic configuration diagram of an engine according to an embodiment of the present invention. FIG. 2 is an enlarged view of the cylinder head shown in FIG. 1, which is a side sectional view taken along a plane that passes through the center of the cylinder and is perpendicular to the cylinder arrangement direction. 2C is a side cross-sectional view of the cylinder head shown in FIG. 1 taken along a plane different from that of FIG. It is a schematic block diagram of one modification of the engine shown by FIG. It is a sectional side view which shows the structure of one modification of the cylinder head shown by FIG. FIG. 7 is a side sectional view showing a configuration of another modification of the cylinder head shown in FIG. 1. It is a schematic block diagram of the other modification of the engine shown by FIG. It is a schematic block diagram of the other modification of the engine shown by FIG. It is a schematic block diagram of the other modification of the engine block shown by FIG. It is a top view of the gasket shown by FIG. It is the schematic block diagram which looked at the engine block of the modification shown by FIG. 8 from upper direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Engine 110 ... Engine block 120 ... Cylinder block 121 ... Cylinder 123 ... Lower jacket (water jacket)
124 ... Cooling water discharge passage 125 ... Cooling water injection passage 126 ... Internal injection passage 130 ... Cylinder head 131 ... Intake port (intake passage)
132 ... Exhaust port (exhaust passage) 134 ... Intake part 135 ... Exhaust part 135a ... Exhaust valve 135b ... Exhaust valve stem 135c ... Exhaust valve stem guide hole 135d ... Exhaust valve stem seal member 136 ... Upper jacket 137 ... Cooling water injection part 137 '... Cooling water injection unit 137 "... Cooling water injection unit 138 ... Cooling water supply passage 138a ... Internal passage 138b ... Connection passage 139 ... Steam discharge passage 140 ... Waste heat recovery portion 141 ... Steam outlet passage 142 ... Superheater (steam heating) vessel)
143 ... Turbine (expander) 144 ... Condenser (condenser)
145 ... Catch tank (cooling medium storage part) 147 ... Supply pump 150 ... Hot water circulation part 151 ... Circulation pump 152 ... Water jet circulation path 153 ... Heater circulation path 154 ... Heater 155 ... Cooling water tank 161 ... Felt member 170 ... Gasket 171 ... Communication hole 172 ... Injection hole

Claims (9)

In an engine configured to recover mechanical energy from waste heat,
An engine block in which a cylinder and an intake passage and an exhaust passage communicating with the cylinder are formed;
A cooling medium injection unit configured to inject a liquid cooling medium toward the engine block;
A steam outlet path configured to lead out the steam of the cooling medium vaporized after being injected by the cooling medium injection section, out of the engine block;
A steam heater that is interposed in the steam lead-out path and configured to heat the steam by heat exchange between the exhaust gas passing through the exhaust passage and the steam;
An expander interposed in the steam outlet and configured to recover mechanical energy from the steam that has passed through the steam heater;
A condenser configured to condense the vapor through the expander;
With
The engine block is
A cylinder head in which the intake passage and the exhaust passage are formed;
A cylinder block formed with the cylinder and a water jacket surrounding the cylinder;
With
The water jacket is formed so as to communicate with a space in the cylinder head in which the cooling medium is ejected by the cooling medium ejection unit.
An upper portion of the cylinder head in the space is connected to the steam outlet path;
An exhaust valve stem guide hole through which an exhaust valve stem that is a rod-like member provided at the lower end with an exhaust valve capable of closing the exhaust passage from the cylinder side is formed in the cylinder head,
A stem seal member for sealing a gap between the exhaust valve stem guide hole and the exhaust valve stem is attached to the cylinder head,
An engine characterized in that a cooling medium supply path for supplying the cooling medium to the cooling medium injection section is formed in the cylinder head so as to pass in the vicinity of the stem seal member. In an engine configured to recover mechanical energy from waste heat,
An engine block in which a cylinder and an intake passage and an exhaust passage communicating with the cylinder are formed;
A cooling medium injection unit configured to inject a liquid cooling medium toward the engine block;
A steam outlet path configured to lead out the steam of the cooling medium vaporized after being injected by the cooling medium injection section, out of the engine block;
A steam heater that is interposed in the steam lead-out path and configured to heat the steam by heat exchange between the exhaust gas passing through the exhaust passage and the steam;
An expander interposed in the steam outlet and configured to recover mechanical energy from the steam that has passed through the steam heater;
A condenser configured to condense the vapor through the expander;
With
The engine block is
A cylinder head in which the intake passage and the exhaust passage are formed;
A cylinder block formed with the cylinder and a water jacket surrounding the cylinder;
With
The water jacket is formed so as to communicate with a space in the cylinder head in which the cooling medium is ejected by the cooling medium ejection unit.
An upper portion of the cylinder head in the space is connected to the steam outlet path;
An exhaust valve stem guide hole through which an exhaust valve stem that is a rod-like member provided at the lower end with an exhaust valve capable of closing the exhaust passage from the cylinder side is formed in the cylinder head,
A stem seal member for sealing a gap between the exhaust valve stem guide hole and the exhaust valve stem is attached to the cylinder head,
The engine, wherein the cooling medium injection unit is configured to inject the cooling medium in the vicinity of the stem seal member. The engine according to claim 2 ,
An engine characterized in that a cooling medium supply path for supplying the cooling medium to the cooling medium injection section is formed in the cylinder head so as to pass in the vicinity of the stem seal member. The engine according to any one of claims 1 to 3 ,
A cooling medium storage unit configured to store the liquid cooling medium condensed in the condenser; and
A cooling medium delivery pump configured to deliver the liquid cooling medium from the cooling medium reservoir to the cooling medium ejection unit;
An engine characterized by further comprising. The engine according to claim 4 ,
The cooling medium delivery pump is
A supply pump configured to deliver the cooling medium from the cooling medium reservoir to the water jacket;
A circulation pump configured to deliver the cooling medium from the bottom of the water jacket to the cooling medium injection unit;
An engine characterized by comprising The engine according to claim 5 ,
The engine, wherein the circulation pump is configured to send the cooling medium to a heater configured to heat a predetermined heating target. The engine according to any one of claims 1 to 6 ,
The engine, wherein the cooling medium injection unit is configured to inject the cooling medium toward a steam discharge path connecting the engine block and the steam outlet path.   In an engine configured to recover mechanical energy from waste heat,
  An engine block in which a cylinder and an intake passage and an exhaust passage communicating with the cylinder are formed;
  A cooling medium injection unit configured to inject a liquid cooling medium toward the engine block;
  A steam outlet path configured to lead out the steam of the cooling medium vaporized after being injected by the cooling medium injection section, out of the engine block;
  A steam heater that is interposed in the steam lead-out path and configured to heat the steam by heat exchange between the exhaust gas passing through the exhaust passage and the steam;
  An expander interposed in the steam outlet and configured to recover mechanical energy from the steam that has passed through the steam heater;
  A condenser configured to condense the vapor through the expander;
  With
  The engine, wherein the cooling medium injection unit is configured to inject the cooling medium toward a steam discharge path connecting the engine block and the steam outlet path. The engine according to claim 7 or claim 8 ,
The engine block is arranged so as to incline to the first side with respect to the vertical direction,
The coolant injection part is an upper part of the engine block and provided on the first side,
The engine is characterized in that the steam discharge path is provided on the second side opposite to the first side, above the engine block.

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