JPS6088817A - Exhaust device - Google Patents

Abstract

PURPOSE:To make pressure inside an exhaust pipe keel in a proper value as well as to aim at a reduction in output loss due to exhaust resistance, by letting a valve, which makes a sectional area of the exhaust pipe variable, operate in response to the said pressure inside the exhaust pipe. CONSTITUTION:A part of an exhaust pipe 1 is made up of double cylinders in type by means of a cylinder 4 held by a stay 9 inside, and a rear end frontage of the cylinder 4 is so designed to be free of opening or closing at one end of a swing valve 3 supported by a shaft 16. The swing valve 3 is driven by an actuator 5 serving as a pressure detecting part, and exhaust gas pressure is made so as to act on one of surfaces of the actuator 5 in design. With this constitution, when the exhaust gas pressure becomes higher, the actuator 5 moves against energizing force in a spring 7 whereby the swing valve 3 is opened in consequence.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an exhaust system for an internal combustion engine, in particular an exhaust system for an internal combustion engine of a motor vehicle.

[Background Art] Among internal combustion engines, those used in automobiles and the like are subject to large variations in load and rotational speed.

The exhaust system connected to such an internal combustion engine is one with a small diameter and slightly longer when the internal combustion engine is a low-speed engine, a slightly thicker and slightly shorter exhaust system when the internal combustion engine is a high-speed engine, and a medium-speed exhaust system. When , it is said that an intermediate between the above two is preferable. This is because the exhaust pipe internal pressure fluctuates greatly depending on the rotational speed of the internal combustion engine, so the exhaust resistance is not always constant.For this reason, the exhaust resistance is small only at a certain rotational speed, and the load due to this exhaust resistance is small. However, there has been no conventional exhaust system that can reduce exhaust resistance and improve internal combustion engine output at all rotational speeds of an internal combustion engine.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to constantly reduce exhaust resistance since the cross-sectional area of the exhaust pipe changes depending on the internal pressure of the exhaust pipe. The present invention provides an exhaust system for an internal combustion engine.

[Disclosure of the Invention 1 The present invention includes a valve that changes the cross-sectional area of the exhaust pipe, and a pressure detection unit that drives the valve to change the cross-sectional area of the exhaust pipe in response to changes in the internal pressure of the exhaust pipe. When the exhaust pipe internal pressure increases and the exhaust resistance increases, the cross-sectional area of the exhaust pipe increases according to the internal pressure, preventing the exhaust pipe internal pressure from rising and reducing the exhaust resistance. This is to prevent it from getting too big.

The present invention will be explained below based on the illustrated embodiment. E in the figure is an internal combustion engine, and its exhaust manifold 10
The exhaust system connected to the engine is composed of a front pipe 11, a catalytic converter 12, a tail pipe 13, and a rear pipe 14. The cooling fins 15 provided between the catalytic converter 12 and the tail vibe 13 are provided to protect from the heat transmitted from the front pipe 11 and the catalytic converter 12 when the tail pipe 13 and subsequent parts are made of aluminum. It is.

Here, the cross-sectional area of the exhaust pipes 1 such as the front pipe 11, tail vibe 13, or 77 roller 14 is set to be thick so that the exhaust resistance is minimized when the rotational speed of the internal combustion engine E becomes high. This exhaust pipe 1
The valve 2 that is installed at any position to narrow down the cross-sectional area is provided with a stay 9 inside the exhaust pipe 1 so that a part of the exhaust pipe 1 becomes a double cylinder as shown in FIGS. 2 and 3. The rear end opening of the held cylinder 4 is formed by making it freely openable and closable by one end of the swing valve 3 supported by the shaft 16.

The swing valve 3 is driven by an actuator 5 serving as a pressure detection section, and the actuator 5 is slidable within a cylinder 6 whose one end communicates with a portion of the exhaust pipe 1 on the side closer to the internal combustion engine E than the cylinder 4. The swing valve 3 is biased by a spring 7 in the direction of closing the rear end opening of the cylinder 4, and when the internal pressure of the exhaust pipe 1 is low, the swing valve 3 is moved by the pressure of the spring 7 to close the rear end opening of the cylinder 4. 4 is closed to reduce the effective cross-sectional area of the exhaust pipe 1.

When the rotational speed of the internal combustion engine E increases and the internal pressure of the exhaust pipe 1 increases, this internal pressure acts on one surface of the actuator 5 in the cylinder 〇, causing the actuator 5 to spring 7.
Since the swing valve 3 is driven against the pressure, the swing valve 3 rotates and opens the rear end opening of the cylinder 4, thereby greatly increasing the effective cross-sectional area of the exhaust pipe 1. The amount by which the rear end opening of the cylinder 4 is opened increases as the internal pressure increases, and the opening amount is increased by one in order to allow a large amount of exhaust gas to flow. In other words, it acts so that the internal pressure of the exhaust pipe 1 is always at a value suitable for the internal combustion engine E.

In the embodiment shown here, the actuator 5 constitutes the pressure detection section, but the structure of the pressure detection section is not limited to this. In other words, the valve 2 may also serve as a pressure detection section, or the pressure detection section may be composed of a pressure sensor that outputs an electrical output, and the valve 2 may be composed of an electromagnetic valve operated by the output of the pressure sensor. can be,
The structure of the valve 2 itself is not limited to the illustrated example, but any structure that can change the cross-sectional area of the exhaust pipe 1 is preferable so that the flow of exhaust gas is not obstructed when the cross-sectional area is narrowed. It is good if there is no such thing.

[Effects of the Invention] As described above, in the present invention, since the cross-sectional area of the exhaust pipe changes depending on the internal pressure of the exhaust pipe, the internal pressure is adjusted to The output loss of the internal combustion engine caused by the exhaust resistance t can be kept small at all times.
There is no need to provide a different exhaust system for each type of internal combustion engine.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the exhaust system, Fig. 2 is a vertical cross-sectional view of the civil engineering invention-embodiment, and Fig. 3 is a cross-sectional view of the same. y) Actuator as a pressure detection part, E indicates an internal combustion engine. Agent Patent Attorney Ishi 1) Chief 7 Figure 1 f S 2 Figure 3

Claims (1)

[Claims] (1) Internal combustion (exhaust system for engine use, with a valve that changes the cross-sectional area of the exhaust pipe, and pressure that drives the valve to change the cross-sectional area of the exhaust pipe in response to changes in the internal pressure of the exhaust pipe) An exhaust device characterized by comprising a detection section.