JPH0315805Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is an exhaust gas recirculation system for engines equipped with pressure wave superchargers that transmits the pressure wave energy of exhaust gas to the intake air, compresses the intake air, and performs supercharging. Regarding a control device.

(Prior art) The above-mentioned pressure wave supercharging utilizes the pressure of exhaust gas and uses the pressure wave energy to compress intake air to perform supercharging. Although the exhaust gas and intake air interfere with each other, conventional was used solely for the purpose of supercharging (for example, the
Publication No. 1153).

Therefore, when attempting to perform exhaust gas recirculation control in an engine equipped with a pressure wave supercharger, it has been necessary to provide a new exhaust gas recirculation device.

(Purpose of the invention) The purpose of this invention is to economically and efficiently control exhaust gas recirculation using a pressure wave supercharger without using a new exhaust gas recirculation device, and to use two unique valves. An object of the present invention is to provide an exhaust gas recirculation control device for an engine equipped with a pressure wave supercharger, which can adjust the EGR amount to suit the operating conditions by properly using these two valves.

(Structure of the device) This device is rotatably supported within a case,
A rotor in which a number of partition walls forming a number of small chambers are arranged radially, an intake inlet and an intake outlet formed in a case at one end of the rotor, and an exhaust outlet formed in a case at the other end of the rotor. An engine with a pressure wave supercharger, which has an inlet and an exhaust discharge port, and supercharges the intake air by transmitting the pressure wave energy of the exhaust gas to the intake air as the rotor rotates, and the engine has an intake port upstream of the intake inlet port. A bypass passage is provided that communicates the passage with an intake passage downstream of the intake discharge port by bypassing the supercharger, and when the engine is started, the intake passage downstream of the intake discharge is closed and the bypass passage is opened. In the pressure wave supercharged engine, the valve opens and closes the bypass passage separately from the valve that closes the intake passage downstream of the intake discharge port, and the valve is operated according to the operating state when exhaust gas recirculation is requested;
The present invention is characterized in that the exhaust gas recirculation control device for an engine equipped with a pressure wave supercharger is provided with a control means that opens and closes so as to control according to the required amount of exhaust gas recirculation.

(Effect of the invention) According to this invention, if the valve provided in the bypass passage mentioned above is opened and the supercharged air from the pressure wave supercharger is controlled to be relieved, the output of the engine can be maintained. However, the pressure of the exhaust gas supplied to the pressure wave supercharger is also reduced. With a pressure wave supercharger, the pressure difference between the intake and exhaust air is reduced, and the exhaust gas is mixed with the intake air. By supplying this exhaust gas mixture air to the engine, exhaust gas recirculation is possible. , the exhaust gas is reburned. the result,
Exhaust gas recirculation is achieved by a pressure wave supercharger, which eliminates the need for special equipment, making it economical and effective.

Further, since the valve provided in the bypass passage described above is used as a starting valve when starting the engine, the structure is also simplified.

Moreover, since the above-mentioned valves are provided in both the above-mentioned bypass passage and the turbocharger discharge downstream, in the region where the supercharging capacity is low (at the time of starting), the supercharger with high inflow resistance is deliberately not allowed to pass through. In addition, the amount of internal EGR is adjusted by closing the turbocharger discharge valve to prevent combustion from worsening, while operating the bypass passage valve during normal driving.

By selectively using the two valves described above, it is possible to adjust the EGR amount to suit the operating conditions.

(Example) An example of this invention will be described in detail below based on the drawings.

The drawings show an exhaust gas recirculation control device for a diesel engine equipped with a pressure wave supercharger. In FIGS. 1 and 2, a pressure wave supercharger 1 has a rotor 3 rotatably supported within a case 2. , this rotor 3 has a large number of partition walls 5 arranged radially around a rotating shaft 4 to form a large number of small chambers 6..., and one end of the rotating shaft 4 extends outside from the case 2, A pulley 7 is fixed to the extending end, and a belt 10 is stretched between the pulley 7 and a pulley 9 fixed to the end of the crankshaft 8. is driven by.

An intake inlet 11 and an intake outlet 12 are formed in the side surface of the case 2 corresponding to one end of the rotor 3, and an exhaust inlet 13 and an exhaust outlet 14 are formed in the other side.

The above-mentioned intake inlet 11 is connected to the atmosphere via a primary intake passage 15 and an air cleaner 16, and the intake outlet 12 is connected to an intake port 18 of the engine 17 via a secondary intake passage 19, and is further connected to an exhaust inlet. 13 is connected to an exhaust port 20 of the engine 17 via a primary exhaust passage 21, and the exhaust discharge port 14 is connected to a secondary exhaust passage 22 and a muffler (not shown).
connected to the atmosphere via.

Note that a surge tank 23 is provided in the above-mentioned primary exhaust passage 21 to buffer exhaust pulsation. In the figure, 24 is an intake valve, 25 is an exhaust valve, 26 is a combustion chamber, and 27 is a piston.

A bypass passage 28 that bypasses the pressure wave supercharger 1 is formed between the primary intake passage 15 and the secondary intake passage 19 .

A closing valve 29 for closing the secondary intake passage 19 when the engine 17 is started is provided in the secondary intake passage 19 at a position upstream of the confluence with the bypass passage 28. The valve 29 is normally biased in the closing direction by a suitable biasing means, and an electromagnet 30 linked to a key switch is disposed outside the passage on the open side of the closing valve 29. When the closing valve 29 is opened by this intake pressure, the closing valve 29 is attracted to keep the passage 19 open.

An on-off valve 31 for opening and closing the bypass passage 28 is provided in the bypass passage 28, and the on-off valve 31 is driven to open and close by an actuator 32, and the actuator 32 is controlled to open and close by a computer 33. Ru.

On the other hand, in the pressure wave supercharger 1 described above, pressure wave energy is originally generated by pushing exhaust gas into the small chamber 6 of the rotor 3, and energy is transferred to the intake air in front of this pressure wave. The transmitted air compresses the intake air, thereby obtaining supercharging. However, when the on-off valve 31 of the bypass passage 28 is opened, less air is supplied to the combustion chamber 26, so the supercharging decreases and the engine 17 The output of the engine decreases, and the pressure of exhaust gas also decreases.

As mentioned above, when the pressure of the exhaust gas decreases, the pressure wave energy generated in the small chamber 6 of the rotor 3 also decreases, and the pressure difference between the exhaust and intake air decreases, and a part of the exhaust gas mixes with the intake air and becomes the intake air. discharged to the side,
Exhaust gas recirculation (internal EGR) is performed.

As shown in FIG. 3A, the above-mentioned exhaust gas recirculation, that is, the demand for EGR, increases in low load regions and decreases in high load regions. Furthermore, in controlling EGR by controlling the opening and closing of the on-off valve 31 described above, as shown in FIG. In a high load region, the EGR% can be lowered by reducing the opening degree of the on-off valve 31.

As a result, as shown in Fig. 3, the on-off valve 3
By increasing the opening degree of 1 from low to high in the low load area and gradually opening it smaller in the high load area, as shown in Fig. 3 A,
Can meet EGR requirements.

Therefore, the above-mentioned computer 33 stores the opening degree of the on-off valve 31 corresponding to the load of the engine 17 and the EGR request (the state shown in FIG. 3) as a map. 1
7 rotational speed signal and accelerator lever opening signal are input.

The operation of the exhaust gas recirculation control device configured as described above will be explained with reference to the flowchart of FIG. 4. When the engine 17 is started, the closing valve 29 of the secondary intake passage 19 is in a closed state. ,
Further, the on-off valve 31 of the bypass passage 28 is open.

Therefore, when starting the engine 17, natural air is taken in through the bypass passage 28, and the closing valve 29 is closed to prevent combustion from worsening.
When the engine 17 starts, the closing valve 29 is opened by the intake pressure of the engine 17 and is attracted by the electromagnet 30, so that the secondary intake passage 19 is maintained in an open state.

When the secondary intake passage 19 mentioned above is opened, the pressure wave supercharger 1 is put into operation and the intake air is supercharged. When the engine 17 starts, in the first and second steps 41 and 42, the computer 32 determines the load range based on the rotational speed signal of the engine 17 and the opening degree signal of the accelerator lever, that is, the load signal. In step 43, the opening value of the on-off valve 31 corresponding to the load is read from the map, and in the fourth step 44, the actuator 32 is operated with the read opening value.
The opening and closing of the on-off valve 31 is controlled via the on-off valve 31. With this control, the on-off valve 31 opens the bypass passage 28 by a set amount.
is opened to relieve the supercharging air, whereby the pressure wave supercharger 1 performs the exhaust gas recirculation based on the above-described pressure drop of the exhaust gas.

By performing exhaust gas recirculation treatment in this manner, a special exhaust gas recirculation device is not required.

Moreover, since the above-mentioned valves 29 and 31 are provided both in the above-mentioned bypass passage 28 and downstream of the intake and discharge port 12 of the pressure wave supercharger 1, the The closing valve 29 on the discharge side of the supercharger is closed so as not to pass through the pressure wave supercharger 1, which has a large inflow resistance, and to prevent deterioration of combustion, while the on-off valve 31 of the bypass passage 28 is operated during normal running. By adjusting the amount of internal EGR.

By selectively using the two valves 29 and 31 as described above, it is possible to adjust the EGR amount to suit the operating conditions.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention; Fig. 1 is an explanatory diagram of the configuration of an exhaust gas recirculation control device, Fig. 2 is a partially cutaway perspective view of a pressure wave supercharger, and A in Fig. 3 indicates the requirements.
Graph showing EGR and load, B in Figure 3 is a graph showing the relationship between EGR, load, and opening of the on-off valve, C in Figure 3 is a graph showing the relationship between the required opening of the on-off valve and load, Figure 4 is a flowchart. DESCRIPTION OF SYMBOLS 1... Pressure wave supercharger, 2... Case, 3... Rotor, 5... Partition wall, 6... Small chamber, 11... Intake inlet, 12... Intake discharge port, 13... Exhaust inlet, 14...Exhaust outlet, 17...Engine, 2
8... Bypass passage, 29... Closing valve, 31...
Opening/closing valve, 32...actuator, 33...computer.

Claims (1)

[Claims for Utility Model Registration] A rotor that is rotatably supported within a case and has a number of radially arranged partition walls forming a number of small chambers, an air intake inlet formed in the case at one end of the rotor, and It has an intake outlet, an exhaust inlet and an exhaust outlet formed in the case on the other end of the rotor, and supercharges the intake by transmitting the pressure wave energy of the exhaust to the intake as the rotor rotates. The engine is equipped with a pressure wave supercharger, and includes a bypass passage that connects the intake passage upstream of the intake inlet and the intake passage downstream of the intake discharge port, bypassing the supercharger, and when starting the engine,
While closing the intake passage downstream of the intake and discharge,
In the pressure wave supercharged engine configured to open the bypass passage, there is provided a valve that opens and closes the bypass passage separately from a valve that closes the intake passage downstream of the intake and discharge port, and a valve that opens and closes the bypass passage according to the operating state. An exhaust gas recirculation control device for an engine equipped with a pressure wave supercharger, which is provided with a control means that opens and closes so as to control the exhaust gas recirculation according to the required amount of exhaust gas recirculation when the recirculation is requested.