JPH04353221A - Engine equipped with turbocharger and recovery turbine - Google Patents

Abstract

PURPOSE:To provide an engine equipped with a turbocharger and a recovery turbine which reduces the compression work of a piston. CONSTITUTION:As for an engine equipped with a turbocharger and a recovery turbine, the effective area of an exhaust passage is increased by forming an exhaust port 11 on a cylinder head 1 and forming an exhaust hole 4 in the lower part of a cylinder 10. In particular, the high pressure exhaust gas supplied from the exhaust hole 4 is sent into a turbocharger 5 in a short time, overwhelming the back pressure, and the exhaust work of a piston 7 is reduced, and the rest exhaust gas supplied from an exhaust port 3 is sent into the upstream side of an energy recovering turbine 6 having a low exhaust pressure. Accordingly, the exhaust energy can be sufficiently recovered by the turbocharger 5 and the energy recovering turbine 6, and the reduction of the engine efficiency can be prevented, and the stay gas left in the cylinder 10 is reduced, and the intake efficiency is improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an engine having a turbocharger and a recovery turbine driven by engine exhaust energy.

0002

2. Description of the Related Art In general, an engine operates by sequentially repeating an explosion stroke (that is, an expansion stroke), an exhaust stroke, an intake stroke, and a compression stroke. There are two methods. A 4-cycle engine has an intake and exhaust port formed in the cylinder head, and each intake and exhaust port is equipped with an intake and exhaust valve. Each stroke is performed by one stroke of the piston, and in the exhaust stroke, the exhaust valve opens as the piston rises. The exhaust gas inside the cylinder is then discharged. Conventionally, engines with a turbocharger and an energy recovery turbine that are driven by exhaust energy use a turbocharger, an energy recovery turbine, etc. connected downstream of an exhaust pipe such as an exhaust manifold connected to an exhaust port, and the exhaust energy generated by the engine is is recovered by a turbocharger, energy recovery turbine, etc. to drive a compressor, or stored in a battery as electrical energy by a generator or electric motor.

In addition, in a four-stroke engine, during the explosion stroke (that is, expansion stroke), exhaust stroke, intake stroke, and compression stroke, the cylinder internal pressure, the opening area of the exhaust valve and the intake valve, and the valve timing are as shown in FIG. The trajectory shown in is shown. FIG. 7 is a graph illustrating the cylinder pressure, the opening area of the exhaust valve and the intake valve, and the valve timing with respect to the engine operating cycle. In FIG. 7, the vertical axis represents the cylinder internal pressure, the exhaust valve opening area, and the intake valve opening area, and the horizontal axis represents the operating cycle. At this time, if the opening timing of the exhaust valve is, for example, the end of the explosion stroke, that is, the crank angle is 180°, then
The exhaust valve opening area is now indicated by the symbol EPS, and the intake valve opening area is now indicated by the symbol IPS. At this time, the cylinder internal pressure draws a locus of symbol P, as shown by the dotted line. The exhaust pressure generated within the manifold is designated by the symbol MP.

In a conventional engine in which exhaust gas is discharged through an exhaust port formed in the cylinder head, for example, if the exhaust valve opens at the end of the explosion stroke, that is, at a crank angle of 180°, the exhaust gas in the cylinder is discharged. is only through the exhaust port, and the effective exhaust passage area is the passage area due to the opening of the exhaust valve. Furthermore, in the above engine, for example, if the exhaust valve opens at the end of the explosion stroke, that is, at a crank angle of 180°, the cylinder pressure P will change as shown in FIG. When the piston is pushed down to perform work, the cylinder pressure P decreases, and when the exhaust valve is opened (for example, at a crank angle of 180°), the exhaust gas in the cylinder is exhausted through the exhaust port formed in the cylinder head. The cylinder pressure P decreases. Next, during the exhaust stroke, the piston rises and the exhaust is exhausted through the exhaust port, but at the end of the exhaust stroke, the exhaust pressure MP of the exhaust manifold increases due to the arrangement of a turbocharger, etc., and the cylinder internal pressure P increases to the manifold gas pressure, that is, the manifold gas pressure. There is no pressure difference between the pressure and the exhaust pressure MP, and the cylinder internal pressure P rapidly rises, as shown by HP near the end of the exhaust stroke (crank angle 360°).

[0005] Further, as a turbo compound engine, there is one disclosed in Japanese Patent Application Laid-Open No. 63-9617. The turbo compound engine has a turbocharger and a turbine connected in series to a main exhaust passage of the engine, and a auxiliary exhaust passage that opens later than the main exhaust passage is connected to the main exhaust passage between the turbocharger and the turbine. ,
The auxiliary exhaust passage is provided with an on-off valve whose opening degree is adjusted based on the operating state of the engine.

[0006]

[Problems to be Solved by the Invention] However, in an engine having a turbocharger and an energy recovery turbine, since a load is applied to rotate the turbocharger turbine and the energy recovery turbine, the exhaust gas such as the exhaust manifold connected to the exhaust port is The exhaust pressure MP within the pipe increases, and the back pressure that opposes the discharge of exhaust gas increases. Therefore, as the piston rises, the pressure difference between the combustion gas pressure P in the cylinder and the gas pressure in the manifold becomes smaller, and a phenomenon occurs in which the combustion gas is not completely exhausted from the cylinder to the manifold. In particular, in engines that discharge exhaust gas from the cylinder by opening an exhaust valve from an exhaust port formed in the cylinder head, if the exhaust gas is discharged as the piston rises, the presence of a turbocharger, energy recovery turbine, etc. The exhaust pressure MP in the manifold increases, and the back pressure that opposes the discharge of exhaust gas into the exhaust manifold increases, causing an increase in the exhaust work of the piston, and reducing the amount of outflow per hour through the exhaust valve. There is a problem in that the cylinder pressure, that is, the cylinder pressure P increases, and the engine efficiency decreases.

Furthermore, near the top dead center of the exhaust stroke, the lift of the exhaust valve becomes smaller, so the flow rate of combustion gas that can be discharged through the exhaust valve decreases in response to the decrease in cylinder internal volume as the piston rises. becomes smaller, and the cylinder internal pressure P rises rapidly, as shown by the symbol HP in FIG. As a result, the piston performs compression work at a pressure higher than the exhaust pressure of the engine, resulting in a decrease in engine efficiency and a decrease in suction efficiency due to an increase in residual gas remaining in the cylinder. Further, the outflow speed of exhaust gas is proportional to the ratio of cylinder internal pressure/exhaust pressure, and when the exhaust pressure is high, the outflow speed of exhaust gas decreases. In particular, in engines such as adiabatic engines and high-output diesel engines, when the boost is increased and the amount of working gas is large, the exhaust gas is not sufficiently exhausted through the normal exhaust valve.

The turbo compound engine disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 63-9617 discharges exhaust gas through the sub-exhaust passage by adjusting the opening degree of the on-off valve according to the operating condition of the engine. In the vicinity of the top dead center of the piston, the pressure inside the cylinder increases as described above, and as a result, the piston performs compression work, making it impossible to solve the above problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems by providing an exhaust port in the cylinder head and an exhaust hole in the lower part of the cylinder to increase the effective area of the exhaust passage. Most of the sufficiently high-speed and high-pressure exhaust gas exhausted from the exhaust hole formed at the bottom of the cylinder is sent to the turbocharger to reduce the amount of exhaust gas in the cylinder, and the subsequent exhaust stroke, that is, the piston rises. To provide an engine having a turbocharger and a recovery turbine that reduce the compression work of a piston during a stroke, prevent a decrease in engine efficiency, and improve suction efficiency by reducing residual gas remaining in a cylinder.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention is constructed as follows. That is,
This invention relates to an exhaust port formed in a cylinder head and provided with an exhaust valve, an exhaust hole formed in the lower part of the cylinder that opens near the bottom dead center of the piston, a turbocharger in which the exhaust hole is communicated through a first exhaust pipe, and the turbocharger. An engine having a turbocharger and a recovery turbine driven by engine exhaust energy, the engine having an energy recovery turbine communicating downstream of the charger through a second exhaust pipe, and a third exhaust pipe communicating the exhaust port with the second exhaust pipe. Regarding.

[0011] Furthermore, in this engine having a turbocharger and a recovery turbine, the timing at which the exhaust valve disposed at the exhaust port opens is delayed from the opening of the exhaust hole.

[0012] Furthermore, this engine having the turbocharger and the recovery turbine is provided with an opening/closing valve that closes the exhaust hole during the intake stroke.

[0013]

[Operation] The engine having a turbocharger and a recovery turbine according to the present invention is constructed as described above, and operates as follows. That is, in addition to an exhaust port formed in the cylinder head, this engine with a turbocharger and a recovery turbine has an exhaust port formed in the lower part of the cylinder that opens near the bottom dead center of the piston, and the exhaust port is connected through a third exhaust pipe. Since it communicates with the energy recovery turbine and the exhaust hole communicates with the turbocharger through the first exhaust pipe, the exhaust hole opens near the bottom dead center of the piston, thereby effectively discharging exhaust gas by the amount of the exhaust hole. As the area increases, the exhaust gas in the cylinder is exhausted to the upstream side of the turbine of the turbocharger through the exhaust hole, and even if the exhaust pressure is high, high-pressure gas from engine blowdown flows out of the exhaust hole in a short time. Therefore, the turbine of the turbocharger can be driven, the compressor can be driven, and if the turbocharger is provided with a generator/motor, the generator/motor can recover electrical energy.

Furthermore, the exhaust manifold, which is the third exhaust pipe, is connected to an energy recovery turbine, and the remaining exhaust gas exhausted from the exhaust port is sent to the energy recovery turbine, so that the remaining exhaust gas exhausted from the exhaust port is fed into the energy recovery turbine, and is discharged into the cylinder near the top dead center of the exhaust stroke. Even if the exhaust gas pressure decreases, the exhaust pressure is considerably low downstream of the turbocharger, that is, upstream of the energy recovery turbine, so the exhaust gas is sufficiently exhausted and the exhaust energy is sufficiently recovered by the energy recovery turbine. Therefore, a considerable amount, for example, 70% of the exhaust gas is discharged from the exhaust hole at the beginning of the exhaust stroke, so the amount of exhaust gas in the cylinder is reduced and the exhaust gas pressure is low, so that during the compression stroke of the piston, The combustion gas pressure has already decreased, and the compression work of the piston during the exhaust stroke, that is, when the piston rises, is reduced.

Furthermore, in this engine having a turbocharger and a recovery turbine, the exhaust valve disposed at the exhaust port opens later than the opening of the exhaust hole, so that the exhaust gas pressure in the cylinder is dispersed. The turbocharger can be driven satisfactorily while maintaining high pressure and high speed without any drop in pressure.

[0016] Furthermore, since the engine having this turbocharger and recovery turbine is provided with an opening/closing valve that closes the exhaust hole during the intake stroke, air flows from the first exhaust pipe through the exhaust hole into the cylinder during the intake stroke. Exhaust gas will not flow back.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an engine having a turbocharger and a recovery turbine according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing an embodiment of an engine having a turbocharger and a recovery turbine according to the present invention, FIG. 2 is an explanatory view showing a turbocharger installed in the engine of FIG. 1, and FIG. FIG. 4 is a sectional view showing details of the lower part of the cylinder formed in the cylinder block of the engine in FIG. 1, FIG. 5 is a sectional view taken along line A-A in FIG. 4, and FIG. 2 is a graph illustrating cylinder pressure, exhaust valve and intake valve opening areas, and valve timing for an operating cycle of an engine having a charger and a recovery turbine.

As shown in the figure, this engine having a turbocharger and a recovery turbine is a four-cycle engine, and includes a turbocharger 5 and an energy recovery turbine 6 that are driven by engine exhaust energy. This four-stroke engine consists of a cylinder block 2, a cylinder head 1 fixed to the cylinder block 2, and a cylinder head 1 fixed to the cylinder block 2.
, a cylinder 10 formed in a cylinder block 2, a piston 7 that reciprocates within the cylinder 10, and a connecting rod 27 and a crankshaft 18 that convert the reciprocating movement of the piston 7 into rotational movement. In FIG. 1, a cylinder 10 formed in a cylinder block 2 is schematically shown. An exhaust port 11 and an intake port 12 are formed in the cylinder head 1, an exhaust valve 9 is arranged in the exhaust port 11, and an intake valve 13 is arranged in the intake port 12. An exhaust port 11 formed in the cylinder head 1 is connected to an exhaust manifold 3, which is a third exhaust pipe, with a manifold gasket 19 interposed therebetween.

In particular, this engine having a turbocharger and a recovery turbine has an exhaust hole 4 that opens at the bottom of the cylinder 10 and near the bottom dead center of the piston.
is connected to the turbine scroll 14 of the turbine 20 in the turbocharger 5 through an exhaust pipe 8 which is a first exhaust pipe, and furthermore, the outlet 25 of the exhaust manifold 3 is connected to the turbine scroll 14 of the turbine 20 in the turbocharger 5.
It is characterized in that it is connected to the outlet 15 of 0. Also,
An outlet 15 of the turbine 20 in the turbocharger 5 is connected to a turbine scroll 17 of the energy recovery turbine 6 through an exhaust pipe 16 that is a second exhaust pipe. Therefore, the piston 7 descends inside the cylinder 10 and approaches the piston bottom dead center (in FIG. 6, the crank angle is 125 during the explosion stroke).
°), the exhaust hole 4 opens and the combustion gas in the cylinder 10 flows from the exhaust hole 4 to the exhaust pipe 8 and the turbine scroll 1.
4 to the turbine 20 of the turbocharger 5. The exhaust valve 9 opens later than the opening of the exhaust hole 4 (in FIG. 6, at the end of the explosion stroke, that is, at a crank angle of 180
°), exhaust gas flows from exhaust port 11 to exhaust manifold 3
a turbine scroll 17 downstream of the turbocharger 5 and upstream of the energy recovery turbine 6;
sent to.

Furthermore, the engine having this turbocharger and recovery turbine is provided with an opening/closing valve 29 that closes the exhaust hole 4 during the intake stroke, as shown in FIGS. 4 and 5. A cylinder liner 2L is fitted into a hole formed in the cylinder block 2.
A cylinder 10 is formed in L. cylinder liner 2
A plurality of (three in FIG. 4) exhaust holes 4 are formed in L, that is, in the lower part of the cylinder 10. The opening/closing valve 29 provided in the exhaust hole 4 can be composed of a reed valve, a rotary valve, etc., but here, an example of the opening/closing valve shown in the figure is shown. One end of a link 31 is fixed to the opening/closing valve 29, and the link 31 is attached to be pivotable at a pivot point 32. The other ends of these links 31 are pivotally connected to a link 30 attached to the actuator 28. Therefore, when the actuator 28 expands and contracts in the direction of the arrow, the opening/closing valve 29 pivots at the pivot point 32 and the exhaust hole 4
is opened and closed. By providing the opening/closing valve 29 in the exhaust hole 4, the actuator 28 can be actuated to close the exhaust hole 4 with the opening/closing valve 29 during the intake stroke. Therefore, the exhaust gas present in the exhaust pipe 8 during the intake stroke is prevented from flowing back into the cylinder 10 through the exhaust hole 4.

Therefore, in the engine having this turbocharger and recovery turbine, the exhaust hole 4 closes to the bottom dead center of the piston.
is opened, the combustion gas in the cylinder 10 is exhausted through the exhaust hole 4 to the upstream side of the turbine 20 of the turbocharger 5, and after the exhaust gas drives the turbine 20, energy is recovered from the outlet 15 of the turbine 20. The exhaust gas is sent to the turbine 23 of the turbine 6, and after driving the turbine 23, it is exhausted to the outside. Therefore, the effective exhaust area for discharging exhaust gas increases by 4 times the exhaust hole, and the exhaust gas in the cylinder 10 is exhausted to the upstream side of the turbine 20 of the turbocharger 5 through the exhaust hole 4.
Even if the exhaust pressure is high, high-pressure gas from engine blowdown flows out from the exhaust hole 4 in a short time, so the turbine 20 of the turbocharger 5 can be driven, and the compressor 22 can be driven, as well as the power generation installed in the turbocharger 5. - Can be recovered as electrical energy by the electric motor 21.

Further, since the exhaust manifold 3 communicates with the energy recovery turbine 6 through the exhaust pipe 16, the remaining exhaust gas exhausted from the exhaust port 11 is transferred to the exhaust pipe 1.
6 to the turbine scroll 17 of the turbine 23 in the energy recovery turbine 6 . Even if the combustion gas pressure in the cylinder 10 decreases near the top dead center of the exhaust stroke, the exhaust pressure is considerably low on the downstream side of the turbocharger 5, that is, on the upstream side of the energy recovery turbine 6, so the exhaust gas is sufficiently exhausted. The exhaust energy is sufficiently recovered by the energy recovery turbine 6. That is, since a considerable amount, for example, 70% of the exhaust gas is discharged from the exhaust hole 4 at the beginning of the exhaust stroke, the amount of exhaust gas in the cylinder 10 is reduced and the exhaust gas pressure is lowered, so that during the exhaust stroke of the piston 7. The combustion gas pressure has already decreased, and the compression work of the piston 7 on the exhaust gas is reduced.

That is, as shown in FIG. 6, the engine having this turbocharger and recovery turbine has an effective exhaust area of the exhaust port 11 indicated by the symbol EPS, as well as an effective exhaust area of the exhaust port 11 indicated by the symbol EH.
The effective exhaust area increases by the effective exhaust area of 4 exhaust holes shown by S, and becomes the total effective exhaust area of the effective exhaust area EPS of the exhaust port 11 and the effective exhaust area EHS of the exhaust hole 4, and the effective exhaust area increases significantly. It will be increased to Moreover, the exhaust hole 4 provided at the bottom of the cylinder 10 is
A large number (three in FIG. 4) can be provided in the circumferential direction of the
A large amount of exhaust gas can be sent from the exhaust hole 4 through the exhaust pipe 8 to the turbine 20 of the turbocharger 5 in a short time.

Therefore, the engine with this turbocharger and recovery turbine has an exhaust port 11 formed in the cylinder head 1 and an exhaust hole 4 formed in the lower part of the cylinder 10.
By discharging the exhaust gas in the cylinder 10 through
As shown by dotted lines P and PX in FIG. 6, the combustion gas pressure in the cylinder 10 decreases, almost reaching the manifold exhaust pressure MP, and in the subsequent exhaust stroke, the combustion gas pressure in the cylinder has already decreased. Therefore, the cylinder pressure inside the cylinder 10 decreases from the cylinder pressure P to the cylinder pressure PX, and the compression work of the piston 7 during the exhaust stroke is indicated by the shaded symbol WX.
It will be reduced by that amount. That is, as shown in FIG. 7, in a conventional engine having a turbocharger and a recovery turbine, when only the exhaust port 11 is open, the cylinder pressure is P0. is exhaust port 11
When the exhaust hole 4 is opened, the cylinder pressure becomes PX, and in this four-stroke engine with a turbocharger, the compression work of the piston 7 is reduced by the shaded symbol WX.

Furthermore, in this engine having a turbocharger and a recovery turbine, the cylinder 10 is
The exhaust gas inside is sent to the turbine 20 of the turbocharger 5, so that the exhaust energy is recovered by the generator/motor 21 of the turbocharger 5 and also by operating the compressor 22. The exhaust gas that has passed through the turbine 20 of the turbocharger 5 and the exhaust gas that has been exhausted from the exhaust port 11 through the exhaust manifold 3 is subsequently sent to the energy recovery turbine 6 through the exhaust pipe 16 and the turbine scroll 17. The turbine 23 is driven.

That is, in this engine having a turbocharger and a recovery turbine, the turbocharger 5 sends exhaust gas from the engine to the turbine 20 through the exhaust hole 4, and rotates the turbine 20 to rotate the shaft 26. The compressor 22 is rotated to supercharge the engine with intake air, and the generator/motor 21 is rotated to operate the generator/motor 21 as a generator to regenerate energy. Also,
The exhaust gas sent to the turbine scroll 17 of the turbine 23 in the energy recovery turbine 6 drives the turbine 23, and the rotational movement of the turbine 23 is caused by the shaft 3.
3, the generator/motor 24 is operated, and the exhaust energy contained in the exhaust gas is sufficiently recovered as electrical energy by the generator/motor 24.

[0027]

Effects of the Invention The engine having a turbocharger and a recovery turbine according to the present invention is constructed as described above, and has the following effects. That is, an engine with this turbocharger and recovery turbine has an exhaust port formed in the cylinder head and equipped with an exhaust valve, an exhaust hole formed at the bottom of the cylinder that opens near the bottom dead center of the piston, and the exhaust hole connected to the first exhaust port. a turbocharger communicating through a pipe, an energy recovery turbine communicating downstream of the turbocharger through a second exhaust pipe, and a third exhaust pipe communicating the exhaust port with the second exhaust pipe;
When the exhaust hole opens near the bottom dead center of the piston, the effective exhaust area increases by the amount of the exhaust hole, and the exhaust gas in the cylinder is exhausted to the upstream side of the turbine of the turbocharger through the exhaust hole. The turbine is driven to drive the compressor, and the exhaust energy is recovered by the generator and electric motor. After the exhaust gas discharged from the exhaust hole drives the turbocharger, the exhaust gas is sent to the energy recovery turbine, and the remaining exhaust gas is exhausted from the exhaust port formed in the cylinder head through the exhaust valve. 3 exhaust pipes or exhaust manifolds downstream of the turbocharger and upstream of the energy recovery turbine, and the remaining exhaust gas drives the turbine of the energy recovery turbine and is exhausted to the outside.

Therefore, in the engine having this turbocharger and recovery turbine, the absolute amount of exhaust gas in the cylinder is reduced through the exhaust port and the exhaust hole at the end of the explosion stroke and at the beginning of the exhaust stroke, resulting in a low exhaust gas pressure. During the exhaust stroke when the piston rises, the amount of exhaust gas in the cylinder has already been reduced, so the compression work of the piston when the piston rises is reduced, and in particular, the pressure inside the cylinder at the end of the exhaust stroke is reduced. Since the residual exhaust gas is small, sufficient intake air is introduced into the cylinder during the subsequent intake stroke, making it possible to improve intake efficiency.

In particular, when a 4-cycle engine with a turbocharger is applied to an adiabatic engine or a high-output diesel engine, even when the boost of the engine is increased and the amount of working gas is increased, the cylinder Since the exhaust gas inside the cylinder is effectively discharged and the pressure inside the cylinder is lowered, the compression work of the piston can be reduced and the suction efficiency can also be improved. Furthermore, the exhaust energy discharged from the cylinder is sufficiently recovered by a turbocharger, an energy recovery turbine, etc. provided downstream of the exhaust manifold, increasing engine efficiency and reducing fuel consumption.

Furthermore, in this engine having a turbocharger and a recovery turbine, the exhaust valve disposed at the exhaust port opens later than the opening of the exhaust hole, so that the exhaust gas in the cylinder is released during the exhaust stroke. It is not exhausted through the exhaust valve until . Therefore,
The exhaust gas pressure in the cylinder is dispersed and does not decrease, and the exhaust gas in the cylinder is at high pressure and high speed near the end of the explosion stroke, and most of it is discharged to the first exhaust pipe through the exhaust hole, and the exhaust gas is at high pressure and high speed. In addition, the fuel is fed into the turbocharger from the first exhaust pipe while maintaining a high-speed state, and the turbine of the turbocharger can be favorably driven.

[0031] Furthermore, since the engine having this turbocharger and recovery turbine is provided with an opening/closing valve that closes the exhaust hole during the intake stroke, the exhaust gas is removed from the first exhaust pipe communicating with the turbocharger during the intake stroke. Exhaust gas does not flow back into the cylinder through the holes, and operating cycles can be repeated smoothly.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of an engine having a turbocharger and a recovery turbine according to the present invention.

FIG. 2 is an explanatory diagram showing a turbocharger provided in the engine of FIG. 1.

FIG. 3 is an explanatory diagram showing an energy recovery turbine provided in the engine of FIG. 1;

FIG. 4 is a sectional view showing details of a lower portion of a cylinder formed in the cylinder block of the engine shown in FIG. 1;

FIG. 5 is a sectional view taken along line AA in FIG. 4;

FIG. 6 is a graph illustrating the cylinder pressure, the opening area of the exhaust valve and the intake valve, and the valve timing for the operating cycle of the engine having the turbocharger and the recovery turbine.

FIG. 7 is a graph illustrating cylinder pressure, exhaust valve and intake valve opening areas, and valve timing with respect to the operating cycle of a conventional engine.

[Explanation of symbols]

1 Cylinder head 2 Cylinder block 3 Exhaust manifold (third exhaust pipe) 4 Exhaust hole 5 Turbocharger 6 Energy recovery turbine 7 Piston 8 Exhaust pipe (first exhaust pipe) 9 Exhaust valve 10 Cylinder 11 Exhaust port 16 Exhaust pipe (second exhaust pipe) Exhaust pipe) 20 Turbine 28 Actuator 29 Opening/closing valve

Claims (3)

[Claims] 1. An exhaust port formed in a cylinder head and provided with an exhaust valve, an exhaust hole formed in the lower part of the cylinder that opens near the bottom dead center of the piston, and a turbocharger in which the exhaust hole is communicated through a first exhaust pipe. an energy recovery turbine that communicates downstream of the turbocharger through a second exhaust pipe; and a third exhaust pipe that communicates the exhaust port with the second exhaust pipe; the turbocharger and recovery turbine are driven by the exhaust energy of the engine; engine. 2. The engine having a turbocharger and a recovery turbine according to claim 1, wherein the exhaust valve disposed at the exhaust port opens later than the opening of the exhaust hole. 3. The engine with a turbocharger and recovery turbine according to claim 1, further comprising an on-off valve that closes the exhaust hole during an intake stroke.