JPH11200870A - Turbo compound engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbo compound engine wherein the case of having a turbo compound mode recovering power from an exhaust turbo supercharger, its sufficient rotation is obtained even in a low or intermediate speed region and output torque of the engine can be high sufficiently maintained. SOLUTION: An engine 1 and an exhaust turbo supercharger 12 are connected by a hear train 13 through an on/off clutch 14, also the exhaust turbo supercharger 12 is formed as a variable nozzle type supercharger, an opening of a variable nozzle 12d is adjusted, so as to synchronize rotation of an intermediate shaft 16 in both sides of the on/off clutch 14 based on a rotational speed of the engine 1 and a rotational speed of the exhaust turbo supercharger 12, and also timing of connection of the exhaust turbo supercharger 12 and the engine 1 by the on/off clutch 14 is arbitrarily controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbo compound engine, and more particularly to a two-cycle or four-cycle internal combustion engine used for general vehicles, cargo handling machines, construction machines, special vehicles, and ships. And useful.

[0002]

2. Description of the Related Art A turbo compound engine utilizes the exhaust energy of the engine to supercharge the air supply. As one type of the turbo compound engine, a crankshaft of the engine and a rotating shaft of an exhaust turbocharger are turned on / off. The power from the exhaust turbocharger side to the engine side is provided in the middle of the gear train so that the engine can be rotated by the exhaust turbocharger while being mechanically connected via a gear train with an OFF clutch interposed. In some cases, a one-way clutch that allows only transmission is interposed. FIG. 4 shows such a turbo compound engine according to the prior art.

As shown in FIG. 4, the turbo compound engine guides exhaust gas from the exhaust pipe of the engine 1 to a turbine 2a of an exhaust turbocharger 2 to rotate the turbine 2a, thereby coaxially with the turbine 2a. The compressor 2b mounted above is driven to pressurize the intake air to the engine 1. At this time, the crankshaft 1a of the engine 1 and the exhaust turbocharger 2
Is mechanically connected to the rotary shaft 2c by a gear train 3, and an ON / OFF clutch 4 and a one-way clutch 5 are interposed in the middle of the gear train 3. More specifically, the gear train 3 includes a crank gear 3a fixed to the crankshaft 1a, gears 3b and 3c fixed to the first intermediate shaft 6, and a second
Gears 3d, 3e, 3f fixed to intermediate shaft 7 and rotating shaft 2
c, and gears 3b, 3c
Between the ON / OFF clutch 4 and the gears 3d, 3e
One-way clutches 5 are interposed therebetween. Here, the ON / OFF clutch 4 is interrupted by a control signal from the control unit 7, and the one-way clutch 5 transmits the rotation of the exhaust turbocharger 2 to the engine 1 when the rotation speed of the exhaust turbocharger 2 is high. Works like that.

The control unit 7 processes a signal sent from the sensor 8 and turns ON / OFF based on a map or the like stored in advance based on information on the number of revolutions of the engine 1 detected by the revolution detection unit 9.
The on / off of the clutch 4 is controlled.

FIG. 5 shows an example of an engine speed / load (engine output torque) characteristic of a turbo compound engine according to the prior art as described above. As shown in the figure, the turbo compound engine has an MD (mechanical drive) mode, an FT (free turbo) mode, and a TCP.
(Turbo compound) mode. The MD mode is a mode in which the power of the engine 1 is transmitted to the exhaust turbocharger 2 via the gear train 3, and the control unit 7
The mode is set by connecting the ON / OFF clutch 4 in response to a control signal from the CPU. In this MD mode,
The exhaust turbocharger 2 is driven not only by the exhaust gas but also by the engine 1, and the output torque of the engine 1 can be increased. Therefore, it is used to increase the transient output torque of the engine 1 during acceleration of the vehicle in order to improve the transient response of the vehicle. Here, the transient response of the vehicle refers to the length of time from when the driver steps on the accelerator to when the vehicle reaches an arbitrary speed. The FT mode is a normal operation mode of the exhaust turbocharger 2, which is set by disengaging the ON / OFF clutch 4 by a control signal from the control unit 7. The TCP mode is a mode in which a part of the power of the exhaust turbocharger 2 is used as the power of the engine 1, and the fuel efficiency is improved accordingly. The mode is O
With the N / OFF clutch 4 disconnected, the rotation speed of the one-way clutch 5 on the exhaust turbocharger 2 side based on the rotation of the exhaust turbocharger 2 is changed to the rotation speed of the engine 1 based on the rotation of the engine 1. When it becomes larger, the one-way clutch 5 automatically realizes it.

[0006]

In the prior art as described above, as shown in FIG. 5, sufficient transient torque in the low speed range of the engine 1 can be obtained by using the MD mode. When the one-way clutch 5 is connected to automatically switch to the TCP mode, there is a problem that steady torque in a low-speed / high-load region is limited to a low level. While the one-way clutch 5 is automatically turned on and off due to a difference in the relative rotation speed between the exhaust turbocharger 2 and the engine 1, when the one-way clutch 5 is connected in the low-speed range of the engine 1, This is because the rotation speed of the exhaust turbocharger 2 is limited to a low value in accordance with the rotation speed of the engine 1, and the supercharging function of the exhaust turbocharger 2 is reduced.

The present invention has been made in view of the above prior art, and in the case where a turbo compound mode for recovering power from an exhaust turbocharger is provided, sufficient rotation of the exhaust turbocharger can be obtained even in a low speed range or a medium speed range. Provided is a turbo compound engine capable of maintaining a sufficiently high output torque of the engine.

[0008]

According to the present invention, there is provided a turbo compound engine configured to utilize exhaust energy of an internal combustion engine for supercharging and mechanically recover the exhaust gas. A variable nozzle type exhaust turbocharger having a variable nozzle that adjusts the turbine nozzle area of the inlet so as to be able to control the number of revolutions, and a rotating shaft of the exhaust turbocharger is used as a crankshaft of an engine. A gear train connected to the gear train, a clutch interposed in the middle of the gear train to intermittently transmit power to the crankshaft, and a rotation speed detection unit for detecting the rotation speed of the exhaust turbocharger and the rotation speed of the engine. And controlling the on / off of the clutch based on each piece of information on the number of revolutions from the number of revolutions detecting section, and the rotation based on the exhaust turbocharger and the rotation based on the rotation of the engine in one and the other of the clutches. And having a control unit which adjusts the degree of opening of the variable nozzle control the rotational speed of the exhaust turbocharger as sake.

According to the present invention as described above, the clutch connection timing can be arbitrarily set under the control of the control unit, and the clutch opening can be adjusted by adjusting the opening of the variable nozzle prior to the clutch connection. The rotation of the side and the exhaust turbocharger side can be synchronized. Therefore, not only the MD mode but also the timing of entering the TCP mode can be freely adjusted, and the TCP mode can be selectively set in a high-speed / high-torque range where a sufficiently high torque can be obtained. In the load region, a steady high output torque is secured by controlling the rotation speed of the exhaust turbocharger by adjusting the variable nozzle in the FT mode.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a turbo compound engine according to an embodiment of the present invention. As shown in the figure, an exhaust turbocharger 12 according to the present embodiment includes a turbine 12a that is driven to rotate by exhaust gas from an exhaust pipe, a compressor 12b that is driven by the turbine 12a to pressurize intake air to the engine 1, and A variable nozzle type having a rotary shaft 12c shared by the turbine 12a and the compressor 12b, and having a variable nozzle 12d for adjusting the turbine nozzle area of the exhaust gas inlet so as to be able to control the number of rotations. is there. This exhaust turbocharger 12
Is mechanically connected to the crankshaft of the engine 1 via a gear train 13 with an ON / OFF clutch 14 interposed. The gear train 13 includes a crank gear 13 a fixed to the crankshaft of the engine 1 and a crank gear 1 a fixed to one end of the intermediate shaft 16.
3a, a gear 13c fixed to the other end of the intermediate shaft 16, a rotating shaft 12c of the exhaust turbocharger 12.
And a gear 13d fixedly engaged with the gear 13c.

The control unit 17 processes the signal sent by the sensor 18 and detects the rotation speed information of the engine 1 detected by the rotation detecting unit 19, and processes the signal sent by the sensor 20 and detects by the rotation detecting unit 21. By inputting rotation speed information of the exhaust turbocharger 12 and performing predetermined information processing according to a predetermined procedure, the ON / OFF clutch 14 is controlled to be connected and disconnected, and the variable nozzle 1 is controlled via the actuator 22.
It is configured to adjust the opening of 2d. That is,
The control unit 17 stores, as map information, the interrelationship of the rotation speed of the engine 1, the output torque, the rotation speed of the exhaust turbocharger 12, the opening degree of the variable nozzle 12d, and the like as parameters. .

As shown in FIG. 2 in detail, the turbine section of the exhaust turbocharger 12 has a variable nozzle 12d, which is a variable stationary blade, disposed on the circumference of a turbine rotor blade 12e. A drive ring 12f is connected to 12d via a link, and by controlling the drive ring 12f, the opening degree of the variable nozzle 12d can be changed to change the nozzle area. Therefore, when the rotation speed of the engine 1 is low, the nozzle area can be reduced to increase the flow rate of the exhaust gas, and the responsiveness of the exhaust turbocharger 12 can be improved.

According to the present embodiment as described above, the connection timing of the ON / OFF clutch 14 can be arbitrarily set under the control of the control unit 17, and the variable nozzle 12d can be set prior to the connection of the ON / OFF clutch 14. By adjusting the opening, the rotation of the ON / OFF clutch 14 on the engine 1 side and the rotation of the exhaust turbocharger 12 side can be synchronized. Therefore, the timing for entering the TCP mode as well as the MD mode can be freely adjusted, and the TC mode can be selectively selected in a high-speed / high-torque range where a sufficiently high torque is obtained.
In the P mode, F
In the T mode, a steady high output torque can be secured by controlling the rotation speed of the exhaust turbocharger 12 by adjusting the variable nozzle. Incidentally, the MD mode is used to increase the transient torque of the engine 1 in order to improve the transient response of the vehicle when the vehicle is accelerating, and is realized by connecting the ON / OFF clutch 14. In the FT mode, the ON / OFF clutch 14 is controlled by the control unit 17.
Is realized by turning off the switch. The rotation speed of the exhaust turbocharger 12 in the FT mode can be controlled by controlling the actuator 22 by the control unit 17 and adjusting the opening of the variable nozzle 12d. The TCP mode is ON / OFF controlled by the control unit 17 under the condition that the rotational speeds of the ON / OFF clutch 14 on the engine 1 side and the exhaust turbocharger 12 side are the same in a high speed / high load range.
This is realized by connecting the clutch 14. ON / O
When connecting the FF clutch 14, this ON / OFF
Number of rotations of clutch 14 on engine 1 side and exhaust turbocharger 1
The rotation speed on the second side needs to be substantially the same, but the adjustment of the rotation speed can be changed by the control unit 17 by processing the rotation speed information of the engine 1 and the rotation speed information of the exhaust turbocharger 12. This is performed by adjusting the opening of the nozzle 12d.

FIG. 3 shows an example of the engine speed / load (engine output torque) characteristic of the turbo compound engine according to the above-described embodiment. As shown in the figure, the turbo compound engine can realize a steady high output torque state of the engine 1 in a low to medium to high torque range. The timing for entering the TCP mode as well as the MD mode can be set arbitrarily, and the rotation speed of the exhaust turbocharger 12 in the low to medium speed / high torque range is adjusted by adjusting the opening of the variable nozzle 12d. Thereby, the desired rotation can be maintained. According to the present embodiment, the switching to the TCP mode without the one-way clutch 5 (see FIG. 4) of the related art is performed by the ON / OFF clutch 14 and the exhaust turbocharger 1.
The adjustment can be performed by adjusting the opening of the second variable nozzle 12d. On the other hand, the transient torque in the low to medium speed range is ON / O
Sufficient output torque can be obtained in the MD mode by connecting the FF clutch 14 and the steady torque by adjusting the opening of the variable nozzle 12d in the FT mode in which the ON / OFF clutch 14 is disconnected. Further, in a high-speed and high-load range, the ON / OFF clutch 14 is connected by synchronizing the rotation of the engine 1 and the rotation of the exhaust turbocharger 12 by adjusting the opening of the variable nozzle 12d, and the TCP mode is set. After entering the variable nozzle 1
The fuel efficiency can be further improved by narrowing the opening of 2d to increase the collection work.

[0016]

As described in detail with the above embodiments, the present invention relates to a turbo compound engine configured to utilize exhaust energy of an internal combustion engine for supercharging of supply air and mechanically recover the exhaust gas. A variable nozzle type exhaust turbocharger having a variable nozzle that adjusts the turbine nozzle area of the inlet so as to be able to control the number of revolutions, and a rotating shaft of the exhaust turbocharger is used as a crankshaft of an engine. A gear train connected to the gear train, a clutch interposed in the middle of the gear train to intermittently transmit power to the crankshaft, and a rotation speed detection unit for detecting the rotation speed of the exhaust turbocharger and the rotation speed of the engine. And controls the on / off of the clutch based on the information on the number of revolutions from the number of revolutions detection unit, and the rotation based on the exhaust turbocharger and the rotation based on the rotation of the engine in one and the other of the clutches. And a control unit for controlling the rotation speed of the exhaust turbocharger by adjusting the opening of the variable nozzle so as to synchronize, so that the timing of clutch connection can be arbitrarily set by control of the control unit. The rotation of the clutch on the engine side and the rotation on the exhaust turbocharger side of the clutch can be synchronized by adjusting the opening of the variable nozzle prior to the connection of the clutch. Therefore, M
In addition to the D mode, the timing to enter the TCP mode can be freely adjusted, and the TCP mode can be selectively set in the high speed / high torque range where a sufficiently high torque can be obtained. In the FT mode, a steady high output torque is secured by controlling the rotation speed of the exhaust turbocharger by adjusting the variable nozzle. As a result, the operating range of each mode is arbitrarily selected so that the three modes of the MD mode, the FT mode, and the TCP mode exhibit the most features, and the steady torque is also reduced in all the ranges from the low speed range to the high speed range. Efficient operation of the engine can be performed in a state where the engine is kept sufficiently high.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a turbo compound engine according to an embodiment of the present invention.

FIG. 2 shows a variable nozzle 12 of the exhaust turbocharger 12 shown in FIG.
FIG. 3 is a partially enlarged view showing d and its vicinity.

FIG. 3 is a characteristic diagram showing an engine speed / torque characteristic of the turbo compound engine shown in FIG. 1;

FIG. 4 is a block diagram showing a turbo compound engine according to the related art.

FIG. 5 is a characteristic diagram showing an engine speed / torque characteristic of the turbo compound engine shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 12 Exhaust turbocharger 12a Turbine 12b Compressor 12c Rotating shaft 12d Variable nozzle 13 Gear train 14 ON / OFF clutch 17 Control unit 18 Sensor 19 Rotation detecting unit 20 Sensor 21 Rotation detecting unit

Claims (1)

[Claims] 1. A turbo compound engine configured to utilize exhaust energy of an internal combustion engine for supercharging air supply and to mechanically recover the air supply. The turbo compound engine includes a variable nozzle for adjusting a turbine nozzle area of an exhaust gas introduction port. A variable nozzle type exhaust turbocharger configured to control the number of revolutions, a gear train connecting a rotating shaft of the exhaust turbocharger to a crankshaft of an engine, and an intervening part in the gear train A clutch for interrupting the transmission of power to the crankshaft, a rotation speed detection unit for detecting the rotation speed of the exhaust turbocharger and the rotation speed of the engine, and a clutch based on each rotation speed information from the rotation speed detection unit. Of the variable nozzle so as to synchronize the rotation of one of the clutches based on the exhaust turbocharger with the rotation of the engine based on the rotation of the engine. Turbocompound engine and having a controller for controlling the rotational speed of the ball supercharger.