JPS6132107Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a supercharged engine that improves re-acceleration responsiveness and prevents thermal deterioration of a catalyst device that purifies exhaust gas.

In an engine equipped with an exhaust turbo supercharger (for example, see Japanese Patent Application Laid-open No. 123366/1983),
When the throttle valve is closed rapidly from the high-speed operation state and deceleration operation begins, there is no place for the compressed air discharged from the turbocharger's supply air blower to escape, and this compressed air flows into the intake air between the throttle valve and the supply air blower. The air is trapped in the passage and further increases in pressure, causing the rotational speed of the intake air blower to drop rapidly.As a result, when the engine is re-accelerated, even if the throttle valve is opened, the specified amount of air cannot be immediately supplied. .

In order to improve these shortcomings, the Japanese Patent Application Publication No.
There is a prior art disclosed in Japanese Patent No. 55-66614.
In this prior art, an air passage that takes out air from an intake passage between an intake air blower and a throttle valve is opened in an exhaust passage or a muffler, and a control valve that opens when the engine decelerates is provided in this air passage. There is. In this way, by opening the control valve when the engine is decelerating, air in the intake passage is released, preventing the rotational speed of the intake blower from decreasing, and improving the re-acceleration performance of the engine.

By the way, the catalyst device installed in the exhaust passage is
It may be heated during high-speed operation and cause thermal deterioration. However, in this prior art, since the air passage is simply connected to the exhaust passage, the air from the air passage is not dispersed throughout the cross section of the exhaust passage. Therefore, relatively low-temperature air hits the catalyst device locally, making it impossible to prevent thermal deterioration of the catalyst device.

This invention was made in order to improve the above-mentioned drawbacks, and when the throttle valve is rapidly closed, the compressed air discharged from the air supply blower is used as a catalytic device to purify the exhaust gas in the exhaust passage. To provide a supercharged engine that improves re-acceleration responsiveness and prevents thermal deterioration of the catalyst device by flowing the exhaust gas toward the upstream side of the exhaust passage in the vicinity of the entrance of the exhaust passage. With the goal.

An embodiment of this invention will be described below based on the drawings.

In the figure, 1 is an engine, 2 is an intake passage provided with a throttle valve 3, 4 is an exhaust passage, and 5 is an exhaust turbo supercharger, and this supercharger 5 is installed upstream of the throttle valve in the intake passage 2. The turbine 7 is driven by the exhaust gas from the engine 1, so that the blower 6 rotates integrally with the exhaust gas from the engine 1. The engine 1 is subjected to intake supercharging. Reference numeral 8 denotes a catalyst device for purifying exhaust gas, which is installed in the exhaust passage 4 downstream of the turbine 7. Reference numeral 9 denotes an air passage, and an inlet 10 of the air passage 9 is located between the blower 6 and the throttle valve 3. The outlet portion 11 opens toward the upstream in the vicinity of the inlet of the catalyst device 8 . Reference numeral 12 designates an electromagnetic on-off valve that is provided in the air passage 9 and is activated when the deceleration switch 13 is turned on.

In the above configuration, when the throttle valve 3 is rapidly closed from a high-speed operation state and deceleration operation begins, the deceleration switch 13 is turned ON by the engine deceleration signal.
becomes. As a result, the on-off valve 12 is energized, and its valve body 14 is retracted by the electromagnetic attraction force. That is, the air passage 9 is opened, and the compressed air discharged from the blower 6 flows out into the exhaust passage 4 through the air passage 9, and the blower 6 of the intake passage 2 and the throttle valve 3
During this period, the pressure rise is suppressed, and the rotational speed of the blower 6 is prevented from rapidly decreasing. As a result, when the engine 1 is reaccelerated, the amount of air intake corresponding to the opening degree of the throttle valve 3 can be quickly obtained, and the responsiveness of the reacceleration is improved.

Further, the outflow air 15 from the air passage 9 to the exhaust passage 4 cools the exhaust gas 16 from the turbine 7 and flows through the vent hole 17 of the catalyst device 8, thereby preventing thermal deterioration of the catalyst device 8. By the way, exhaust gas 1
6 generally flows strongly locally to the catalyst device 8. For example, in this embodiment, the exhaust passage 4 faces the center of the cross section of the catalyst device 8;
Exhaust gas 16 flows strongly into the center of catalyst device 8.
Here, in this invention, the outflow air 15 becomes a flow opposite to the exhaust gas 16 at the outlet section 11 of the air passage 9, so that the exhaust gas 16 is dissipated around the outlet section 11. As a result, the exhaust gas 16 containing the unburned portion is effectively dispersed throughout the cross section of the exhaust passage 4, and thermal deterioration of the catalyst device 8 is more effectively prevented.

As can be seen from the above explanation, according to this invention, when the throttle valve is rapidly closed, the compressed air discharged from the air supply blower is transferred to the exhaust passage, which is the inlet of the catalyst device that purifies the exhaust gas. Since it flows out into the vicinity, the response of re-acceleration is improved, and
Since the above-mentioned outflow is made toward the upstream side of the exhaust passage, it becomes a counterflow with the exhaust gas, so that the exhaust gas is dispersed over the entire cross section of the exhaust passage, and the supercharging prevents thermal deterioration of the above-mentioned catalyst device. A built-in engine can be provided.

[Brief explanation of drawings]

The drawing is a schematic diagram of a supercharged engine according to an embodiment of the invention. 2...Intake passage, 3...Throttle valve, 4...
Exhaust passage, 5...Exhaust turbo supercharger, 6...Blower, 7...Turbine, 8...Catalyst device, 9...Air passage, 12...Opening/closing valve.

Claims (1)

[Scope of utility model registration request] It is equipped with an exhaust turbo supercharger that supercharges the intake air by driving a blower installed upstream of the throttle valve in the intake passage by a turbine installed in the exhaust passage, and a catalyst device is installed in the exhaust passage downstream of the turbine. In the supercharged engine, the air passage for taking out air from the intake passage between the blower and the throttle valve is an exhaust passage near the entrance of the catalyst device, and the air passage opens toward the upstream side of the exhaust passage. A supercharged engine characterized in that the air passage is provided with an on-off valve that opens during deceleration.