JPH0612070B2 - Turbo Compound Organization - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a turbo compound engine.

[Prior Art] In the turbo compound engine disclosed in Japanese Utility Model Laid-Open No. 60-157941, the bypass valve provided in the middle of the pipe connecting the turbocharger and the power turbine is closed only when the accelerator pedal is depressed. Supply the exhaust to the power turbine,
When the accelerator pedal is released, the bypass valve is opened and the exhaust gas from the turbocharger is discharged directly to the outside.

According to the turbo compound engine described above, the power turbine can be effectively driven in partial load operation and full load operation, and exhaust energy can be absorbed as power. Also,
In no-load operation with small exhaust energy, it is possible to avoid waste of driving the power turbine.

[Problems to be Solved by the Invention] However, in the case of a turbo compound engine mounted on a vehicle, not only the response delay of the turbocharger but also the response delay of the power turbine are overlapped during the rapid acceleration operation. A shaft output loss occurs as shown by the broken line.

On the other hand, in the rapid deceleration operation, the output of the power turbine continues to be generated, while the crankshaft of the engine decreases in rotation speed, so excessive reverse torque acts on the output of the power turbine,
It may damage the fluid clutch or transmission.

An object of the present invention is to provide a turbo compound engine that stops driving of a power turbine at the time of sudden acceleration / deceleration in order to solve the above problems.

[Means for Solving the Problem] In order to achieve the above object, the structure of the present invention connects a turbocharger and a power turbine in sequence to an exhaust pipe of an engine, and connects the turbocharger and a power turbine. A bypass valve that discharges exhaust gas from the turbocharger when the valve is open is installed in the middle of the pipe, and the rotational fluctuation rate of the engine is calculated based on the signal from the engine speed sensor that is installed on the crankshaft of the engine. Equipped with an electronic control unit, the bypass valve is closed by output to the electronic control unit when the engine rotation fluctuation rate is smaller than a predetermined value, and the bypass valve is output by output to the electronic control unit when the engine rotation fluctuation rate is larger than the predetermined value. It was opened.

[Operation] The engine speed fluctuation rate is calculated by the electronic control unit from the signal from the engine speed sensor. When the rotational fluctuation rate of the engine is smaller than a predetermined value (determined in consideration of the strength of the fluid clutch, transmission, etc.), the bypass valve is closed by the output of the electronic control unit. Exhaust gas from the turbocharger turbine is introduced into the power turbine through a bypass valve, and the exhaust energy is recovered as power by the engine.

When the rotational fluctuation rate of the engine is larger than the predetermined value, the bypass valve is opened by the output of the electronic control unit. Exhaust gas emitted from the turbine of the turbocharger is discharged to the outside through the connecting pipe and the bypass valve, and the power turbine does not introduce the exhaust gas. The power turbine is not driven, avoiding damage to the fluid clutch and transmission.

Embodiment of the Invention As shown in FIG. 1, an exhaust pipe 4 connected to an exhaust manifold 3 of an engine 2 is connected to an inlet of a turbine 8 of a turbocharger 5, and an outlet of the turbine 8 is connected to a connecting pipe 9. Connected to the inlet of the power turbine 12. Power turbine 12
Is connected to the exhaust pipe 26 and is opened to the outside through a silencer. In the turbocharger 5, an impeller of a turbine 8 and an impeller of a blower 6 are connected by a shaft 7, and intake air is pressurized by the blower 6 and supplied to the engine 2.

The shaft 13 of the power turbine 12 is connected to the sun gear of the planetary gear reducer 14, while the shaft 15 of the ring gear is connected to the input side of the fluid clutch 16. The output side of the fluid clutch 16 is connected to the input gear 21 of the speed reducer 18 via the shaft 17, and the output gear 24 of the speed reducer 18 is connected to the crankshaft 19 of the engine 2.

Note that the fluid clutch 16 is supplied with lubricating oil that lubricates the engine 2 as operating oil, and passes through the check valve 39 to the oil pan 4
Returned to 0.

Outlet of turbine 8 of turbocharger 5 and power turbine 1
A bypass valve 10 is provided in the middle of the connection pipe with the inlet of the second valve 2. When the bypass valve 10 is opened, the outlet side of the turbine 8 is communicated with the bypass pipe 20, and the exhaust gas is directly discharged to the outside and sent to the power turbine 12. I can't. The bypass valve 10 is opened during the sudden acceleration operation and the sudden deceleration operation of the engine, and is closed during the normal operation. That is, when the engine speed fluctuation rate is smaller than the predetermined value, the bypass valve 10 is closed by the output to the electronic control device, and when the engine speed fluctuation rate is larger than the predetermined value, the bypass valve 10 is bypassed by the output to the electronic control device. The valve 10 is opened.

In the illustrated embodiment, an engine speed sensor 35 is arranged on the crankshaft 19 of the engine 2, and a signal from the engine speed sensor 35 is input to an electronic control unit 36 composed of a microcomputer to change the engine speed with time. From this, the rotation fluctuation rate is calculated. The bypass valve 10 is opened and closed by the output of the electronic control unit 36 based on the rotation fluctuation rate. The bypass valve 10 is configured as an electromagnetic valve. For example, when the electromagnetic coil or the electromagnetic actuator is energized, the bypass valve 10 is opened, and conversely, when it is de-energized, the bypass valve 10 is closed.

FIG. 2 is a flow chart of the control program described above.
p15 is shown at each step. At p11, the engine speed based on the signal from the speed sensor 35 is sequentially input, and at p12, the rotational fluctuation rate is calculated from the engine speed input at every predetermined time. p
At 13, it is determined whether or not the rotation fluctuation rate is larger than the predetermined value α. When the rotation fluctuation rate is smaller than the predetermined value α, the bypass valve 10 is closed at p15. On the other hand, the rotation fluctuation rate is a predetermined value α
If it is larger than that, the bypass valve 10 is opened at p14.

[Advantages of the Invention] As described above, the present invention is configured to control the opening / closing of the bypass valve arranged between the turbocharger and the power turbine in relation to the rotational fluctuation rate. In rapid acceleration operation, the bypass valve is opened, only the turbocharger is operating, and the power turbine is stopped.Therefore, temporary loss / decrease in shaft output due to driving the power turbine and acceleration performance Deterioration is avoided.

In addition, even when the engine suddenly decelerates, the bypass valve is opened and the power turbine is not driven.Therefore, the fluid clutch due to the excessive reverse torque transmitted from the crankshaft of the engine to the output shaft of the power turbine through the transmission and the fluid clutch. And damage to gears in the gear transmission are avoided.

On the other hand, in normal operation, the bypass valve is closed and the power turbine is driven, so exhaust energy is effectively recovered as power, stable running is obtained, and shaft output and running fuel consumption are improved. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a turbo compound engine according to the present invention, FIG. 2 is a flow chart of a control program for operating a bypass valve in the turbo compound engine by a micro computer, and FIG. 3 is a transient during rapid acceleration of the turbo compound engine. It is a diagram showing characteristics. 2: internal combustion engine, 5: turbocharger, 9: connecting pipe, 10:
Bypass valve, 12: power turbine, 14: planetary gear reducer, 16: fluid clutch, 18: reducer, 19: crankshaft, 20: bypass pipe, 35: engine speed sensor,
36: Electronic control unit

Claims (1)

[Claims] 1. A turbocharger and a power turbine are sequentially connected to an exhaust pipe of an engine, and the exhaust gas from the turbocharger at the time of opening the valve is externally provided in the middle of a pipe connecting the turbocharger and the power turbine. Equipped with a bypass valve that discharges to the engine, equipped with an electronic control unit that obtains the engine speed fluctuation rate based on the signal from the engine speed sensor installed on the engine crankshaft, and the engine speed fluctuation rate is smaller than a specified value. A turbo compound engine, characterized in that the bypass valve is closed by output to the electronic control unit, and the bypass valve is opened by output to the electronic control unit when the rotational fluctuation rate of the engine is larger than a predetermined value.