JPS5857020A - Intake controller of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve combustion efficiency in a light load range, by constituting the captioned device, equipped with an exhaust turbosupercharger, in such a manner that a compressor, the supercharger, is stopped in the light load range and the like of an engine to feed air to the engine bypassing the compressor. CONSTITUTION:In a high load range of an engine 1, exhaust from the engine 1 reaches a turbine 4 in a supercharger 2 through an exhaust passage 9 to drive the turbine, and then is discharged, here air in an intake passage 6 is compressed by a compressor 3, connected to the turbine 4 by a shaft 5, and supercharged to the engine 1. While in a light load range of the engine 1, an exhaust control valve 16, provided in an exhaust bypass passage 13, is opened by output of a load sensor 18 through a controller 21, and the supercharger 2 is stopped. Then an intake control valve 14, provided in the downstream end of an intake bypass passage 12, is opened by a pressure difference between both the intake and feed air passages 6, 7, thus air can be supplied to the engine 1 through the intake bypass passage 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake control device for an internal combustion engine equipped with an exhaust turbocharger.

When an exhaust turbo supercharger is installed as a supercharging means for an internal combustion engine, although supercharging is not necessarily required in the no-load operating range and light-load operating range of the L1 engine, This may worsen the fuel consumption rate of the engine. In other words, regardless of whether the internal combustion engine is a diesel engine or a gasoline engine, in operating ranges where the fuel demand of the engine is small, such as in light load operating ranges including no-load, it is necessary to supply the minimum amount of air into the cylinders. If the exhaust turbo supercharger is operated in this range, the excess air ratio will become too high and the engine's pumping loss will increase, and the exhaust resistance will increase due to the turbine, resulting in high engine back pressure. As a result, the exhaust efficiency decreases and the combustion conditions deteriorate, resulting in a disadvantage that the fuel consumption rate becomes worse compared to a non-supercharged engine.

The present invention has been made in view of the above nine points, and is capable of improving the fuel consumption rate in the light load range including no load while maintaining high output performance and fuel consumption rate in the high load range. The present invention provides an intake control device with a simple configuration.

The present invention will be explained in detail below based on illustrated embodiments.

A compressor 8 of an exhaust turbo supercharger 2 is interposed in the intake system of the internal combustion engine 1, and a turbine 4 of the supercharger 2 is interposed in the exhaust system of the engine 1 to connect the compressor 8 and the turbine 4. They are interlocked via shaft 5 and 7. Reference numeral 6 denotes an intake passageway connecting the secondary side of the air cleaner (not shown) to the air inlet of the compressor 3, 7a an air supply passageway extending from the outlet of the compressor 3 to the intake manifold 8 of the engine 1;
#i An exhaust passage from the exhaust manifold 1° of the engine 1 to the exhaust inlet of the turbine 4. Reference numeral 11 denotes an exhaust passage leading from the exhaust outlet of the turbine 4 to the atmosphere via a muffler, etc. (not shown).

Here, in the present invention, an intake bypass passage 12 is provided which bypasses the compressor 8 and communicates the intake passage 6 and the air supply passage 7.
Bypassing the turbine 4, the exhaust passage 9 and the exhaust passage 1 are
1 is provided.

When the pressure in the intake passage 7 is higher than the pressure in the intake passage 6, such as when the exhaust turbo supercharger 2 is in operation, an intake bypass passage is provided at the connection between the intake bypass passage 12 and the intake passage 7. 1
An intake control valve 14 is provided which closes the intake bypass passage 12 and opens the intake bypass passage 12 when the pressure in the intake passage 6 becomes higher than the pressure in the intake passage 7, such as when the supercharger 2 is at rest. Further, an exhaust control valve 16 having the exhaust bypass passage 13Kti actuator 15 is provided, and a load sensor 18 provided on the fuel injection pump 17 of the engine 1 and a rotation sensor sensor for detecting the rotation speed of the crankshaft 19 of the engine 1 are provided. By supplying the output to the controller 221 of the actuator 15, the exhaust control valve 16 is opened in a light load operation range including no load and a high load high rotation range.

In the above configuration, when the engine 1 is operated, the exhaust gas discharged through the exhaust manifold 10 is introduced into the turbine 4 through the exhaust passage 9, and the turbine 4 is driven by the energy of this exhaust gas. Then, this driving force is transmitted to the compressor 3 via the shaft 5, so the compressor 8 compresses the air in the intake passage 6 and sends it to the air supply passage 7. Therefore, when the engine 1 is operating under normal conditions, the pressure in the intake passage 7 is maintained at a positive pressure even though the pressure in the intake passage 6 is in a negative pressure state close to atmospheric pressure. Supercharging is carried out during the period.

When it is sensed by the output of the load sensor 18 that the engine 1 is being operated in a light load range close to no load, a valve opening signal is sent from the controller 21 to the actuator 15 . Then, the exhaust control valve 16, which was in the fully closed state at the top, is switched to the fully open state, so that the exhaust manifold 1G
Most of the exhaust gas flowing into the exhaust passage 9 from the exhaust passage 9 flows into the exhaust passage 11 through the exhaust bypass passage 13 with low resistance.

For this reason, in the first light load operating range, the driving force of the turbine 4 is almost exhausted tl, the compressor 8 is substantially stopped, and the supercharger 2 is stopped.

Then, the flow rate of air sent from the intake passage 6 to the air supply passage 7 through the compressor 8 becomes smaller than the required flow rate of the engine 1, so that the air supply passage 7 tends to have a negative pressure. However, when the pressure balance in the inner passage 6.7 is reversed (when the 1li4 feeder is stopped), the intake control valve 14 automatically opens due to the pressure difference, so the air passes through the intake bypass passage 12 with low resistance. Air flows into the air supply passage 7. Therefore, since the engine operates as a non-supercharged engine in a light load operating range including no load, the fuel consumption rate in this range can be improved to the same level as a non-supercharged engine even though it is a supercharged engine.

When the load on the engine l reaches a predetermined value, the valve opening signal flowing from the controller 21 to the actuator 15 disappears. Then, the exhaust control valve 16 returns to its closed state and closes the exhaust bypass passage 13, so that the exhaust from the exhaust passage 9 is poor and is guided to the turbine.

That is, in the middle cylinder load range where the exhaust energy is sufficiently large, the exhaust gas is guided to the turbine 4 and the compressor 8 is operated, so that supercharging is performed by the compression action of the compressor 8, improving combustion conditions and reducing the fuel consumption rate. In addition to improving the intake efficiency, the amount of fuel supplied can be increased, so the output per cylinder volume can be increased.

Note that even after the exhaust control valve 16 is closed, until the rotation speed of the supercharger 20 rises sufficiently and the pressure in the air supply passage 7 becomes higher than the pressure in the intake passage 6, in other words, supercharging is substantially stopped. Of course, the intake control valve 14 is open until the start of the engine to prevent a drop in intake efficiency, and the rise in the discharge air flow rate of the compressor 3, such as during sudden acceleration, is caused by the dispersion air flow lid of the engine 1. Even when there is a delay in start-up (when the start-up of the supercharger is delayed), the intake control valve 14 automatically opens and replenishes air to the air supply passage 7. Deterioration of exhaust gas is prevented.

Further, when the engine 1 is operated in a high-load, high-speed range, a valve opening signal flows from the controller 21 to the actuator 15 based on the output of the rotation sensor. Then, the exhaust control valve 16 provided in the exhaust bypass passage 13 opens, preventing the maximum cylinder pressure from rising excessively due to excessive supercharging, and reducing the i
Sound, vibration.

4 durability etc. is guaranteed.

In the above embodiment, pressure is applied directly to the intake control valve 14 to open and close it, but as shown in FIG. is configured to open and close the intake control valve 14 using a diaphragm actuator U or the like that guides the pressure in the air supply passage 7 to the other pressure chamber 23, and prevents the valve 14 from wobbling. You may also do so, and
The pressure in both passages 6.7 may be detected using a pressure sensor or the like, and the intake control valve 14 may be controlled to open or close using electromagnetic force or the like based on the result. The intake control valve 14 may be configured with the upper valve. Also, the exhaust control valve 16
does not necessarily have to be one; conventionally known wastegate pulp and an exhaust control valve that opens in the light load operating range may be installed in parallel as described above. It is best to provide only the exhaust control valve that opens.

As explained above, according to the present invention, in the light load range where the efficiency of the supercharger is significantly reduced, the exhaust control valve is opened to stop the supercharger, and then the When a drop in supply air pressure occurs, the intake control valve automatically opens, bypassing the compressor and supplying air to the engine, unlike conventional turbocharged engines. It is possible to prevent a decrease in fuel consumption in the light load range, insufficient output during acceleration operation, and worsening of smoke.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of one embodiment of the present invention, and FIG. 2 is a sectional view of essential parts showing another embodiment of the present invention. 1... Internal combustion engine 2... Exhaust turbo supercharger 8... Compressor 4... Turbine 12.
...Intake bypass path 13...Exhaust bypass path 1
4... Intake control valve 15... Actuator 1
6...Exhaust control valve 18...Load sensor addition...
・Rotation sensor 21...Controller Sae...Diaphragm actuator Patent applicant Hino Motors Co., Ltd.

Claims (1)

[Claims] In an internal combustion engine equipped with an exhaust turbo supercharger, an intake bypass passage that communicates between upstream and downstream of the compressor of the supercharger and an exhaust bypass passage that communicates between the upstream and downstream of the turbine of the supercharger are provided. An exhaust control valve that is opened when the load is low is provided in the exhaust bypass passage, and
An intake air control device for an internal furnace engine, characterized in that an intake bypass passage is provided with an intake control valve that opens when the pressure upstream of the compressor becomes higher than the pressure downstream of the compressor.