JPH1162632A - Exhaust device of internal combustion engine with turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine with turbocharger, which does not cause defective engine running even if defective operation is caused in an exhaust throttle valve. SOLUTION: An exhaust throttle valve 40 is arranged in an exhaust manifold 31 upper-stream of a turbocharger 10 and is supplied with negative pressure when a negative pressure control valve 70 is opened when the temperature of the cooling water of an engine is lower than the specified value previously set to throttle the flow passage in the exhaust manifold 31. When a flow passage is throttled to the opening value previously set or less, and back pressure increases much enough to overcame the energizing force of the spring in a bypass flow control valve 50, the bypass flow control valve openes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exhaust system for a turbocharged internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine equipped with a turbocharger, there is known an engine in which an exhaust throttle valve is disposed upstream of a turbocharger in order to improve engine warm-up properties (see Japanese Utility Model Application Laid-Open No. 56-139830). . By arranging the exhaust throttle valve on the upstream side of the turbocharger in this way, the back pressure of the turbocharger cannot be increased, so that it is possible to prevent exhaust leakage from the turbocharger and each joint. However, since the exhaust throttle valve is disposed upstream of the turbocharger, the exhaust throttle valve is exposed to high-temperature exhaust gas as compared with the case where the exhaust throttle valve is provided downstream of the turbocharger, and the exhaust throttle valve is subject to sludge accumulation, seizure, and thermal deformation. When an operation failure occurs, there is a problem that a desired output cannot be obtained.

[0003]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an exhaust device for a turbocharged internal combustion engine which does not cause a malfunction of the engine even if a malfunction of an exhaust throttle valve occurs. Aim.

[0004]

According to the first aspect of the present invention, there is provided an exhaust system for a turbocharged internal combustion engine having a turbocharger disposed in an engine exhaust pipe, wherein operating state detecting means detects an operating state. And an exhaust arranged in the exhaust pipe on the upstream side of the turbocharger and, when the operating state is in a predetermined state, is operated to restrict the flow path of the exhaust pipe to a predetermined opening degree. A throttle valve, a bypass passage for bypassing the exhaust throttle valve, and a bypass flow control valve disposed in the bypass passage, wherein a predetermined flow path of the exhaust pipe is predetermined when the exhaust throttle valve is throttled. An exhaust system is provided in which the bypass flow control valve is opened so as to compensate for the insufficient opening of the exhaust throttle valve when the throttle valve is throttled to the opening degree or less. In the exhaust device for an internal combustion engine with a turbocharger configured as described above, when the exhaust throttle valve is throttled and the flow path of the exhaust pipe is reduced to a predetermined opening degree or less, the bypass flow rate control is performed. The valve opens so as to compensate for the insufficient opening of the exhaust throttle valve.

According to a second aspect of the present invention, in the first aspect of the present invention, when the temperature of the engine is equal to or lower than a predetermined temperature,
An exhaust device is provided in which an exhaust throttle valve is operated to restrict the flow path of the exhaust pipe to a predetermined opening degree. In the exhaust device for an internal combustion engine with a turbocharger configured as described above, when the engine is at or below a predetermined temperature, the exhaust throttle valve narrows the flow path of the exhaust pipe to a predetermined opening. When the throttle is operated and the flow path of the exhaust pipe is reduced to a predetermined opening degree or less at that time, the bypass flow control valve opens so as to compensate for the insufficient opening degree of the exhaust throttle valve.

According to a third aspect of the present invention, in the first aspect of the invention, the bypass flow control valve is opened when the exhaust pressure upstream of the exhaust throttle valve becomes larger than a predetermined value. An exhaust system is provided. In the exhaust device configured as described above, the bypass flow control valve opens when the exhaust pressure upstream of the exhaust throttle valve becomes larger than a predetermined value.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing the overall structure of a turbocharged internal combustion engine equipped with the exhaust device of the present invention. In FIG. 1, reference numeral 1 denotes the body of the engine,
0 is a turbocharger. Turbocharger 1
The intake pipe 21 is connected to the inlet side of the compressor 20, and the intake manifold 22 is connected to the outlet side. An air cleaner 23 and an air flow meter 24 are disposed in the intake pipe 21 from the upstream side. Intake manifold 2
2 is provided with a throttle valve 25.

On the other hand, an exhaust manifold 31 is connected to the inlet side of the turbine 30 of the turbocharger 10, and an exhaust pipe 32 is connected to the outlet side. An exhaust throttle valve 40 is provided in the exhaust manifold 31, and a portion of the exhaust manifold 31 on the upstream side of the exhaust throttle valve 40 and an exhaust pipe 32.
Are communicated by a bypass passage 33. A bypass flow control valve 50 is provided in the bypass passage 33. Numeral 60 denotes a so-called waste gate valve, which discharges exhaust gas when the supercharging pressure becomes too high.
To flow through the exhaust pipe 32 without passing through the turbine 30.

Since the exhaust throttle valve 40 is driven by the suction pipe negative pressure as described later, the exhaust throttle valve 40 is connected to the intake manifold 22 downstream of the throttle valve 25 through the negative pressure introduction line 26, and in the middle of the negative pressure introduction line 26. Is provided with a negative pressure control valve 60 for controlling the introduction of a negative pressure to the exhaust throttle valve 40. The opening and closing of the negative pressure control valve 70 is controlled by an electronic control unit (ECU) 100.

The ECU 100 is composed of a digital computer and has an input interface circuit 1
01, CPU (microprocessor) 102, RAM
(Random access memory) 103, ROM (read only memory) 104, output interface circuit 105
Consists of The CPU 103 controls the engine 1 according to the present invention.
Cooling water temperature sensor 110 and throttle valve 25
A signal for opening and closing the negative pressure control valve 70 based on a signal from the throttle opening sensor 120 attached to the
In addition, signals from various sensors are input via the input interface circuit 101, and various control signals such as fuel injection amount are sent out.

FIG. 2 is a view for explaining the structure and operation of the exhaust throttle valve. FIG. 2 (A) shows a state where the flow of exhaust gas is being throttled, and FIG. 2 (B) shows a state where the flow of exhaust gas is not throttled. . FIG.
4A and 4B, reference numeral 41 denotes a diaphragm chamber, and a diaphragm 42 is disposed inside the diaphragm chamber 41 with its periphery fixed. An actuation rod 43 is fixed to the diaphragm in a suitable manner. The operating rod 43 extends to the outside of the diaphragm chamber 41, and one end of a connecting rod 44 is rotatably attached to an end thereof. One end of a lever 45 is rotatably attached to the other end of the connecting rod 44. A shaft 46 is fixed to the other end of the lever 45. The shaft 46 extends into the exhaust manifold 31, and a valve body 47 is fixed to the shaft 46 in the exhaust manifold 31.

On the other hand, a spring 48 is disposed below the operating rod 43 in the figure, and the spring 48 constantly urges the operating rod 43 upward in the figure. A hole 49 for introducing a negative pressure is provided at the bottom of the diaphragm chamber 41, and the negative pressure introducing line 26 (see FIG. 1) is connected. In FIG. 2A, a negative pressure is introduced into a lower portion inside the diaphragm chamber 41, and the diaphragm 42 is moved to the diaphragm chamber 4.
2, the valve element 47 restricts the flow path of the exhaust manifold 31, and no negative pressure is introduced in FIG. The valve body 47 does not restrict the flow path of the exhaust manifold 31.

The exhaust throttle valve 40 is provided for improving the warm-up of the engine 1 and is provided with a cooling water temperature sensor 110.
The detected cooling water temperature is equal to or less than a predetermined value,
When the throttle opening detected by the throttle opening sensor 120 is equal to or less than a predetermined value, the negative pressure control valve 7
0 is opened, the negative pressure is supplied to the exhaust throttle valve 40, and the flow path of the exhaust manifold 31 is throttled as described above.

FIG. 3 is a view for explaining the structure and operation of the bypass flow control valve 50. FIG. 3A shows a closed state and FIG. 3B shows an open state. 3 (A),
Referring to (B), the valve support member 5 is provided in the bypass passage 33.
1, a spring 52 is attached to the valve support member 51 by an appropriate method, and a valve body 53 is attached to the spring 52 by an appropriate method.

When sludge accumulates on the valve body 47 of the exhaust throttle valve 40 and / or the exhaust manifold 31, when the exhaust throttle valve 40 is actuated, a gap between the valve body 47 of the exhaust throttle valve 40 and the exhaust manifold 31 is formed. The gap is reduced or the gap is eliminated. When the valve element 47 of the exhaust throttle valve 40 is fixed in the above state or further in the above state, the back pressure increases. Then, the force of pressing the valve body 53 of the bypass flow control valve 50 by the back pressure overcomes the urging force of the spring 53, opening the bypass passage 33 and preventing the engine from malfunctioning. Spring 5
3, the opening pressure of the bypass flow control valve 50 is set higher than the back pressure when the exhaust throttle valve 40 normally narrows the flow path of the exhaust manifold 31, and in such a case, , The bypass flow control valve 50 remains closed.

[0016]

According to the present invention, when the exhaust throttle valve narrows the flow path of the exhaust manifold to a predetermined opening degree or less, the bypass flow control valve opens, so that the engine is operated. Defects can be avoided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall structure of an embodiment of the present invention.

2A and 2B are diagrams illustrating the structure and operation of an exhaust throttle valve, wherein FIG. 2A shows a case where the exhaust throttle valve narrows a flow path of an exhaust manifold, and FIG. 3 shows a case where the flow path is not restricted.

3A and 3B are diagrams illustrating the structure and operation of a bypass flow control valve, wherein FIG. 3A shows a case where the bypass flow control valve closes a bypass passage, and FIG. Is open.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 10 ... Turbocharger 20 ... Compressor 30 ... Turbine 31 ... Exhaust manifold 32 ... Exhaust pipe 33 ... Bypass passage 40 ... Exhaust throttle valve 50 ... Bypass flow control valve 60 ... Waste gate valve 70 ... Negative pressure control valve 100 ... ECU 110 ... Cooling water temperature sensor

Claims (3)

[Claims] 1. An exhaust device for a turbocharged internal combustion engine having a turbocharger disposed in an engine exhaust pipe, comprising: operating state detecting means for detecting an operating state; and disposed in an exhaust pipe upstream of the turbocharger. When the operating state is in a predetermined state, an exhaust throttle valve that is operated to restrict the flow path of the exhaust pipe to a predetermined opening degree, and a bypass passage that bypasses the exhaust throttle valve. A bypass flow rate control valve disposed in the bypass passage, wherein when the exhaust throttle valve is throttled, the flow path of the exhaust pipe is reduced to a predetermined opening degree or less. An exhaust system wherein the control valve opens so as to compensate for the insufficient opening of the exhaust throttle valve. 2. An exhaust throttle valve is operated to throttle an exhaust pipe to a predetermined opening degree when the engine temperature is equal to or lower than a predetermined temperature. 2. The exhaust device according to 1. 3. The valve according to claim 1, wherein the bypass flow control valve is opened when an exhaust pressure upstream of the exhaust throttle valve becomes larger than a predetermined value.
The exhaust device according to claim 1.