JPS6030424Y2 - Exhaust turbo supercharging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust turbocharging device, and more particularly to an exhaust turbocharging device equipped with an exhaust bypass device or an exhaust switching device.

The biggest problem when combining an exhaust turbo supercharging device with an engine is that the exhaust pressure does not increase when the engine is rotating at low speed, so the compressor rotation may also increase because the turbine cannot rotate at high speed. However, sufficient boost pressure is not generated.

What is even more inconvenient in this case is that engines equipped with the above-mentioned exhaust turbo supercharging system inevitably have greater intake and exhaust resistance, resulting in even lower output than engines without this. It is a point.

Therefore, we tried to solve this problem by selecting a turbine that could rotate at high speeds even when the engine was running at low speeds, but when the engine was running at high speeds, the exhaust pressure rose too much and the boost pressure became abnormally high. A situation may occur in which the maximum allowable explosion pressure of the engine is exceeded and the engine may be destroyed.

In order to solve such problems, exhaust bypass devices have been developed.

As mentioned above, in an exhaust turbo supercharging system that uses a turbine that can obtain high boost pressure even when the engine rotates at low speed, the boost pressure does not fall below the set value when the engine rotates at high speed. In this case, the exhaust gas is to be released in a detour without being supplied to the turbine.
As shown in FIG. 1, the exhaust duct 12 connected to the inlet 11 of the turbine 10 and the outlet 13 are provided with a detour 14 connecting the exhaust duct 12 and the outlet 13, and a control valve 15 is disposed therebetween to control the boost pressure P in the intake duct 16. When the value exceeds a set value, the actuator 17 responds and opens the control valve to bypass the exhaust gas from the turbine 10.

In the figure, 18 is a compressor directly connected to the turbine 10, 19 is an air cleaner, 20 is an engine, and 21 is a compressor directly connected to the turbine 10.
22 is an exhaust valve, 23 is a piston, and 24 is a combustion chamber.

By the way, since the control valve 15 in the exhaust bypass device is a normally closed valve and is exposed to exhaust gas, it may become stuck due to the heat and carbon particles contained therein, and the opening operation may be prevented. There is a possibility that it will not be possible.

If the control valve 15 is not opened in this way, when the boost pressure rises abnormally, it will not be possible to bypass the exhaust gas, which may prevent the boost pressure from rising, which may lead to engine destruction. .

Therefore, this kind of thing must be avoided at all costs.

Furthermore, Japanese Patent Application Laid-Open No. 54-137514 discloses an output control device for an exhaust turbocharger for an internal combustion engine in which the downstream side and upstream side of a compressor are connected by a return passage having an on-off valve. In this case, installing an exhaust turbocharger, providing an exhaust bypass passage, and furthermore providing the above-mentioned return passage would not only require a large-scale supercharging device but also complicate the structure around the engine. There is a risk that the product may become damaged.

Further, Japanese Utility Model Publication No. 54-37721 discloses a valve mechanism that opens and closes the EGR passage in conjunction with the exhaust brake valve, but since both valves close or open at the same time, the boost It cannot be used as a means to prevent an abnormal rise in pressure.

The present invention was devised in view of the above-mentioned points, and is an exhaust turbo supercharging system equipped with an exhaust bypass device as a first boost pressure abnormality prevention device, without making the supercharging system large-scale. The purpose is to provide a second boost pressure abnormality prevention device that does not complicate the structure around the engine, and its gist is to install a control valve that detects the set boost pressure and operates in the exhaust bypass device. The present invention also provides an exhaust turbo supercharging device comprising an exhaust shutter that closes an exhaust pipe on the outlet side of the turbine when a boost pressure higher than the set boost pressure is generated.

An embodiment of the exhaust turbocharging device of the present invention will be described below. In FIG. 2, reference numeral 10 is a turbine;
1 is the inlet, 13 is the outlet, 12 is the exhaust duct, 14
1 is a detour connecting the inlet and the outlet; 15 is a control valve for an exhaust bypass device disposed therebetween; 16 is an intake duct; 17 is an actuator for operating the control valve;
8 is a compressor, 19 is an air cleaner, 20 is an engine, 21 is an intake valve, 22 is an exhaust valve, and 24 is a combustion chamber, which is connected to the intake duct 16 in the same way as the exhaust turbocharger shown in FIG. 1 shows an engine with an exhaust turbo supercharging device equipped with an exhaust bypass device in which a control valve 15 opens a detour 14 in response to boost pressure P in the engine.

Further, BE is an exhaust brake device, and the turbine 1
Exhaust shutter ES disposed on the exhaust pipe 25 connected to the exit 13 of 0, and a power cylinder PC that controls opening and closing of the shutter.
1 A solenoid valve MV that controls the transmission of negative pressure as a power source in the vacuum tank vT to the power cylinder, a manual switch MS as a deceleration detection system, an accelerator switch AS, and a clutch for controlling the opening and closing of the solenoid valve. It is equipped with switches C3, etc., and when all of these switches MS, AS, and C3, which are wired in series, are turned on, it is determined that deceleration is occurring, and the power supply B and the above-mentioned solenoid valve MV are connected and opened. The negative pressure in the tank VT is introduced into the power cylinder PC, and the exhaust shutter ES closes the exhaust pipe 25.

The configuration of this exhaust brake device BE is the same as that of conventionally known devices.

In the present invention, in particular, the exhaust brake device B
The three switches MS, AS, of the deceleration detection system in E
Separately from the C3 system and in parallel with this system, the power source B and the solenoid valve MV can be connected via a pressure switch circle, and the switch is configured to prevent the boost pressure P from increasing abnormally. It is designed to turn on when the

Incidentally, the boost pressure P2 at which the pressure switch is turned on is greater than the boost pressure P1 at which the control valve 15 is opened.

In the exhaust turbocharging device of the present invention having the above configuration, when the boost pressure P is below P1, the exhaust bypass device and the pressure switch PS do not operate, so the control valve 15
The detour 14 is closed and the entire amount of exhaust gas is supplied to the turbine 10, and the exhaust brake device BE does not perform any other work than to function as a conventionally known exhaust brake.

When this boost pressure P reaches Pl, the actuator 17 is actuated to open the control valve 15, and part of the exhaust gas is bypassed to the detour path 14 to limit the rotation of the turbine 10. Rotation is suppressed and boost pressure is prevented from increasing.

In this state, the pressure switch PS is not turned on, so the exhaust brake device BE operates in the same manner as in the above state.

In this state, if the control valve 15 is not opened sufficiently due to a stick or the like and the boost pressure P becomes 12 or higher, the pressure switch PS senses this and turns on, and each switch MS, AS, C3, etc. The solenoid valve MV is opened and the exhaust pipe 25 is closed with the exhaust shutter ES, regardless of the state of the exhaust pipe 25.

As a result, the pressure difference (exhaust pressure) between the inlet 11 and outlet 13 of the turbine 10 is eliminated, the rotation of the turbine is restricted, and an increase in boost pressure is prevented.

As described above, the exhaust turbo supercharging device of the present invention is provided with a control valve that detects the set boost pressure in the exhaust bypass device and operates, and when a boost pressure higher than the set boost pressure is generated, the The exhaust bypass device is equipped with an exhaust shutter that closes the exhaust pipe on the exit side of the engine, and an exhaust shutter can be added as a second boost pressure abnormality prevention device to the exhaust bypass device, which is the first boost pressure abnormal rise prevention device. In addition to providing a more reliable exhaust turbo supercharging device, the device is simpler as it only requires installing an exhaust shutter on the exhaust pipe and operating it with an actuator, compared to the conventional system with a re-turn passage described above. Therefore, there is no need to increase the scale of the supercharging device, and there is no need to complicate the structure around the engine.

The present invention is based on the conventionally known exhaust brake system BE.
The above effect can be obtained by simply adding a pressure switch PS to the system, so it can be said that it is extremely practical.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an outline of a conventionally known exhaust turbo supercharging device, and FIG. 2 is a system diagram showing an outline of an exhaust turbo supercharging device according to the present invention. 10: Turbine, 12: Exhaust duct, 14: Detour, 1
5: Control valve, 16: Intake duct, 17: Actuator, 18: Compressor, 20: Engine, 25: Exhaust pipe, BE: Exhaust brake device, MV: Solenoid valve, PS: Pressure switch, ES: Exhaust shutter, B: power supply.

Claims (1)

[Scope of utility model registration request] An exhaust turbo comprising a control valve that detects and operates a set boost pressure in an exhaust bypass device, and an exhaust shutter that closes an exhaust pipe on the outlet side of the turbine when a boost pressure higher than the set boost pressure is generated. Supercharging device.