JP4735434B2 - Supercharging system for internal combustion engines - Google Patents

Description

  The present invention relates to a technical field of a supercharging system for internal combustion such as a turbocharger mounted on an engine, for example.

  For the purpose of improving engine output, a technique for installing a turbocharger (supercharger) in the engine is known. Furthermore, in order to improve the responsiveness of the turbocharger, in addition to the exhaust gas supplied from the exhaust manifold, the auxiliary air stored in the pressure accumulation tank is supplied to the exhaust gas of the turbocharger. A technique is known in which unburned components are burned to raise the exhaust gas temperature and increase the flow rate of the exhaust gas, thereby increasing the rotational speed of the exhaust turbine (see Patent Documents 1 and 2). Auxiliary air is supplied to the exhaust turbine as necessary by opening and closing a valve provided in a pipe connecting the pressure accumulating tank and the exhaust turbine according to the engine speed (see Patent Documents 3 and 4). .

Japanese Patent Laid-Open No. 62-276221 Japanese Utility Model Publication No. 56-169422 Japanese Utility Model Publication No. 58-152522 Japanese Utility Model Publication No. 58-144030

  However, if the diameter when the valve is opened is relatively large, a large amount of auxiliary air is supplied (that is, sprayed) to the exhaust turbine in a short period of time, so the rotational speed of the exhaust turbine increases rapidly. As a result, the rotational speed of the exhaust turbine becomes excessively large. Furthermore, since the consumption amount of auxiliary air is large, the energy for increasing the rotational speed of the exhaust turbine decreases with the passage of time, and as a result, the rotational speed of the exhaust turbine decreases. That is, it becomes difficult or impossible to stabilize the rotational speed of the exhaust turbine or to smoothly increase it to the steady rotational speed, resulting in a technical problem that the transient performance of the turbocharger deteriorates. On the other hand, when the diameter when the valve is opened is relatively small, the energy for increasing the rotational speed of the exhaust turbine is small, resulting in a technical problem that turbo lag occurs.

  The present invention has been made in view of, for example, the above-described conventional problems, and provides a supercharging system for an internal combustion engine that can improve the stability of a turbocharger, for example, when supplying auxiliary air. The task is to do.

The supercharging system for an internal combustion engine of the present invention includes a supercharger including an exhaust turbine, a pressure accumulation tank that supplies auxiliary air to the exhaust turbine, and a flow rate of the auxiliary air that is supplied from the pressure accumulation tank to the exhaust turbine. The adjusting means for adjusting and the predetermined period after the vehicle starts accelerating, the flow rate in the middle period of the predetermined period is greater than 0 and less than the flow rate in the initial and late periods of the predetermined period. And a control means for controlling the adjusting means.

  According to the supercharging system for an internal combustion engine of the present invention, the exhaust gas discharged from the internal combustion engine rotates the exhaust turbine, and the compressor connected to the exhaust turbine compresses the intake air accordingly. By supplying this compressed intake air to the internal combustion engine, the output of the internal combustion engine can be improved. Furthermore, in addition to the exhaust gas, auxiliary air (for example, compressed air) is supplied (in other words, blown) from the pressure accumulation tank to the exhaust turbine, so that the rotation of the exhaust turbine can be further promoted. In addition to improving the output of the internal combustion engine, the time lag (that is, turbo lag) for improving the output can be improved.

  In the present invention, in particular, the predetermined period after the vehicle starts to accelerate is compared with the flow rate of the auxiliary air in the initial period (or early acceleration period) and the later period (late acceleration period) of the predetermined period. The flow rate of the auxiliary air in the middle period (or in the middle period of acceleration) decreases. That is, during a predetermined period after the vehicle starts accelerating, a first predetermined amount of auxiliary air is first supplied from the pressure accumulator tank to the exhaust turbine, and then a second predetermined amount of auxiliary air that is smaller than the first predetermined amount. Air is supplied from the pressure accumulation tank to the exhaust turbine, and then a third predetermined amount of auxiliary air, which is greater than the second predetermined amount, is supplied from the pressure accumulation tank to the exhaust turbine. Alternatively, during a predetermined period after the vehicle starts accelerating, first, the maximum flow amount of auxiliary air is supplied from the pressure accumulation tank to the exhaust turbine, and then the flow rate is suppressed and auxiliary air is supplied from the pressure accumulation tank to the exhaust turbine. The auxiliary air with the maximum flow rate is again supplied from the accumulator tank to the exhaust turbine.

  As a result, the flow rate of the auxiliary air in the initial stage is not unnecessarily reduced, and the turbo lag immediately after the start of acceleration of the vehicle can be improved. Further, after a while after the vehicle starts to be accelerated, the flow rate of the auxiliary air decreases, so that there is little or no possibility that the rotational speed of the exhaust turbine excessively increases. Further, after a while after the flow rate of the auxiliary air is decreased, the flow rate of the auxiliary air is increased again, so that it is possible to prevent, for example, a decrease in the rotational speed of the exhaust turbine in the late stage of acceleration. Thus, by controlling the flow rate of the auxiliary air by dividing the predetermined period after the vehicle starts acceleration into three stages, the rotational speed of the exhaust turbine can be increased smoothly or stably. The rotational speed of the exhaust turbine can be stabilized. In other words, the stability of the supercharging system for an internal combustion engine can be improved.

  In one aspect of the supercharging system for an internal combustion engine of the present invention, the adjusting means is a valve having a variable opening area provided in a pipe connecting the exhaust turbine and the accumulator tank.

  According to this aspect, the flow rate of the auxiliary air supplied from the pressure accumulation tank to the exhaust turbine can be adjusted relatively easily according to the open / closed state of the valve and the degree of opening when the valve is open. it can.

  Specifically, for example, during a predetermined period after the vehicle starts accelerating, the valve opening area in the middle period of the predetermined period is smaller than the valve opening area in the initial period and the latter period of the predetermined period. Become. That is, during a predetermined period after the vehicle starts accelerating, auxiliary air is first supplied from the accumulator tank to the exhaust turbine with the valve opening area set to the first size, and then the valve opening area is increased. Auxiliary air is supplied from the pressure accumulator tank to the exhaust turbine in a state where the second size is smaller than the first size, and then the opening area of the valve is set to a third size larger than the second size. In this state, auxiliary air is supplied from the pressure accumulation tank to the exhaust turbine. Alternatively, for a predetermined period after the vehicle starts accelerating, the valve opening area is initially set to the maximum (that is, the valve opening area is the same as the cross-sectional area of the pipe, Fully open state) Auxiliary air is supplied from the accumulator tank to the exhaust turbine, then the valve is throttled, auxiliary air is supplied from the accumulator tank to the exhaust turbine, and then the valve opening area is set to the maximum again. Air is supplied from the accumulator tank to the exhaust turbine.

  In another aspect of the supercharging system for an internal combustion engine of the present invention, the control means maintains the state in which the rotational speed of the exhaust turbine is equal to or lower than a predetermined rotational speed at least in a middle period of the predetermined period. Control the adjusting means.

  According to this aspect, it is possible to suitably prevent an excessive increase in the rotational speed of the exhaust turbine.

  More specifically, when it is determined that the rotational speed of the exhaust turbine may exceed the predetermined rotational speed at an early stage of the predetermined period, the rotational speed of the exhaust turbine is equal to or lower than the predetermined rotational speed. The flow rate of the auxiliary air is decreased so as to maintain the above state. In other words, after it is determined that the speed of the exhaust turbine can exceed the predetermined rotational speed after the acceleration of the vehicle is started, the subsequent period can be the middle period of the predetermined period ( That is, it can be the initial period of the predetermined period). Then, when there is no possibility that the rotational speed of the exhaust turbine exceeds the predetermined rotational speed, the flow rate of the auxiliary air is increased again. In other words, after the flow rate of the auxiliary air is once reduced, if there is no possibility that the rotational speed of the exhaust turbine exceeds the predetermined rotational speed, the subsequent period can be the latter part of the predetermined period (that is, until then) Can be the middle of a given period). That is, the distinction between the initial period, the middle period, and the latter period of the predetermined period in the present invention is not necessarily defined directly by the unit of “time”, but may be performed based on, for example, the rotational speed of the exhaust turbine.

  Of course, it is preferable to control the adjusting means not only in the middle period of the predetermined period but also in the initial stage and the latter period of the predetermined period so that the rotational speed of the exhaust turbine is not more than the predetermined rotational speed.

  In the aspect of the supercharging system for an internal combustion engine in which the adjusting means is controlled so that the rotational speed of the exhaust turbine is kept below the predetermined rotational speed as described above, the predetermined rotational speed is supplied by the auxiliary air. It may be configured to be the steady rotational speed of the exhaust turbine when not.

  If comprised in this way, since the rotation speed of an exhaust turbine can be maintained in the steady rotation speed or less, it can prevent suitably that the rotation speed of an exhaust turbine increases excessively. As a result, the stability of the internal combustion engine supercharging system can be improved.

  The operation and other advantages of the present invention will become more apparent from the embodiments described below.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(1) Basic Configuration First, a basic configuration of an embodiment according to the supercharging system for an internal combustion engine of the present invention will be described with reference to FIG. FIG. 1 is a block diagram conceptually showing the basic structure of the embodiment according to the supercharging system for an internal combustion engine according to this embodiment.

  As shown in FIG. 1, the supercharging system for an internal combustion engine according to this embodiment includes, for example, an exhaust turbine 11, a compressor 12, a rotor shaft 13, an air cleaner 14, an intercooler 15, an accumulator tank 21, a check valve 22, an auxiliary valve. A compressed air pipe 23, an auxiliary compressed air supply device 24, a flow rate adjusting electromagnetic valve 25, an air assist pipe 26, an ECU (Electric Control Unit) 30, and the like are configured.

  Exhaust gas discharged from the cylinder 2 of the engine 1 is sprayed to the exhaust turbine 11 via the exhaust manifold 3. The exhaust turbine 11 is rotated by the exhaust gas. As the exhaust turbine 11 rotates, the compressor 12 connected to the exhaust turbine 11 via the rotor shaft 13 also rotates in the same manner. At this time, the intake air supplied to the compressor 12 via the air cleaner 14 is compressed by the rotation of the compressor 12, and then passes through the intercooler 15 to lower its temperature. Thereafter, the compressed intake air is supplied into the cylinder 2 of the engine 1 through the intake manifold 4.

  Thereby, since a large amount of air can be supplied into the cylinder 2 of the engine 1, the output of the engine 1 can be improved.

  Further, in the supercharging system for an internal combustion engine according to the present embodiment, the exhaust turbine 11 includes auxiliary compressed air (auxiliary compression) accumulated in the accumulator tank 21 in addition to the exhaust gas discharged from the cylinder 2 of the engine 1. Air) is sprayed.

  Specifically, the auxiliary compressed air is generated by the operation of the auxiliary compressed air supply device 24 including, for example, a pump. The generated auxiliary compressed air is accumulated in the pressure accumulating tank 21 via the auxiliary compressed air pipe 23. At this time, in order to prevent the auxiliary compressed air accumulated in the pressure accumulating tank 21 from flowing back to the auxiliary compressed air supply device 24, the auxiliary compressed air pipe 23 has an auxiliary only from the auxiliary compressed air supply device 24 to the pressure accumulating tank 21 side. A check valve 22 is provided that allows compressed air to flow.

  The auxiliary compressed air accumulated in the pressure accumulating tank 21 is sprayed to the exhaust turbine 11 through the air assist pipe 26. At this time, the flow rate adjusting electromagnetic valve 25 constituting one specific example of the “adjusting means” in the present invention is injected into the exhaust turbine 11 under the control of the ECU 30 constituting one specific example of the “control means” in the present invention. Adjust the flow rate of auxiliary compressed air that is attached (ie, supplied). For example, when the flow regulating electromagnetic valve 25 is in a closed state, auxiliary compressed air is not sprayed onto the exhaust turbine 11. On the other hand, when the flow rate adjusting electromagnetic valve 25 is in an open state, auxiliary compressed air having a flow rate according to the degree of opening of the flow rate adjusting electromagnetic valve 25 (that is, the opening area) is sprayed onto the exhaust turbine 11. . The adjustment operation of the flow rate of the auxiliary compressed air sprayed from the pressure accumulation tank 21 to the exhaust turbine 11 will be described in detail later (see FIGS. 2 to 5).

  As a result, unburned components in the exhaust gas are burned to raise the exhaust gas temperature and increase the flow rate of the exhaust gas. As a result, the rotational speed of the exhaust turbine can be increased. In particular, even when the amount of exhaust gas emission is small, such as in the low-speed rotation range of the engine in the early stage of acceleration of the vehicle, the rotational speed of the exhaust turbine 11 can be suitably increased, and as a result, so-called turbo lag is improved. can do.

(2) Operation Principle Next, with reference to FIG. 2, the operation principle of the supercharging system for an internal combustion engine according to this embodiment (specifically, the auxiliary compressed air sprayed from the accumulator tank 21 to the exhaust turbine 11). The principle of the flow rate adjustment operation will be described. FIG. 2 shows the flow of the operation of the supercharging system for an internal combustion engine according to the present embodiment (specifically, the operation of adjusting the flow rate of the auxiliary compressed air sprayed from the pressure accumulation tank 21 to the exhaust turbine 11). It is a flowchart shown notionally.

  As shown in FIG. 2, it is determined whether or not the vehicle has started acceleration (step S101). For example, when the engine 1 is in a full load state by depressing the accelerator pedal from a state where the engine 1 is in a low-load steady operation of 2/5 load or less at an arbitrary low rotational speed between 1000 and 1500 rpm, It may be determined that the vehicle has started to accelerate. Alternatively, it may be determined whether the vehicle has started acceleration by directly detecting the longitudinal acceleration with a sensor or the like.

  As a result of the determination in step S101, the vehicle has not started acceleration (specifically, for example, the vehicle is stopped, the vehicle is traveling at a substantially constant speed, or the vehicle is decelerating). If it is determined (step S101: No), the operation of determining whether or not the vehicle has started acceleration is continued.

  On the other hand, as a result of the determination in step S101, when it is determined that the vehicle has started acceleration (step S101: Yes), first, under the control of the ECU 30, the opening area of the flow rate adjusting electromagnetic valve 25 is air. The opening area of the flow rate adjusting electromagnetic valve 25 is set so as to be the same or substantially the same as the pipe area of the assist pipe 26 (step S102). In other words, at the initial stage when the vehicle starts acceleration (that is, in the initial stage of acceleration), the opening area of the flow rate adjusting electromagnetic valve 25 is maximized under the control of the ECU 30 (that is, the flow rate adjusting electromagnetic valve 25 is fully opened). The opening area of the flow rate adjusting electromagnetic valve 25 is set. For this reason, the auxiliary compressed air accumulated in the pressure accumulating tank 21 is sprayed onto the exhaust turbine 11 while maintaining the maximum flow rate.

  Thereafter, after a predetermined time has elapsed, under the control of the ECU 30, the opening area of the flow rate adjusting solenoid valve 25 is set so that the opening area of the flow rate adjusting solenoid valve 25 is smaller than the pipe area of the air assist piping 26. (Step S103). In other words, the opening area of the flow rate adjusting solenoid valve 25 is set so that the opening area of the flow rate adjusting solenoid valve 25 is narrowed under the control of the ECU 30 during the middle period of acceleration after the initial acceleration period has elapsed.

  Specifically, the opening area of the flow regulating electromagnetic valve 25 will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a cross section of the flow rate adjusting electromagnetic valve 25 and the air assist pipe 26.

  As shown in FIG. 3A, when the opening area of the flow regulating solenoid valve 25 is the maximum, the opening area is the same as or substantially the same as the pipe area of the air assist pipe 26.

  On the other hand, as shown in FIG. 3B, when the opening area of the flow rate adjusting electromagnetic valve 25 is narrowed, a part of the pipe of the air assist pipe 26 is blocked by the flow rate adjusting electromagnetic valve. For this reason, the auxiliary compressed air accumulated in the accumulator tank 21 is sprayed onto the exhaust turbine 11 while maintaining a flow rate smaller than the maximum flow rate. That is, the flow rate of the auxiliary compressed air in the middle stage of acceleration is reduced as compared with the early stage of acceleration.

  Thereafter, after a predetermined time has elapsed, under the control of the ECU 30, the opening of the flow rate adjusting solenoid valve 25 is set so that the opening area of the flow rate adjusting solenoid valve 25 is the same as or substantially the same as the pipe area of the air assist piping 26. An area is set (step S104). In other words, the opening area of the flow rate adjusting solenoid valve 25 is set so that the opening area of the flow rate adjusting solenoid valve 25 is maximized under the control of the ECU 30 in the latter half of the acceleration period after the initial period of acceleration and the middle period of acceleration. Is done. For this reason, the auxiliary compressed air accumulated in the pressure accumulating tank 21 is sprayed onto the exhaust turbine 11 while maintaining the maximum flow rate. That is, the flow rate of the auxiliary compressed air in the latter half of acceleration is increased compared to the middle half of acceleration.

  In addition, the timing of the initial stage of acceleration, the middle period of acceleration, and the late stage of acceleration, the opening area of the flow rate adjusting electromagnetic valve 25 in the middle period of acceleration, etc. It is preferable that each vehicle is defined by a table or the like. Alternatively, an optimum value may be calculated each time under the control of the ECU 30 in accordance with the characteristics of the vehicle, the characteristics of the engine 1, and the characteristics of the supercharging system for the internal combustion engine. In this case, the correlation between the timing of the initial stage of acceleration, the middle period of acceleration and the late stage of acceleration, the opening area of the flow regulating electromagnetic valve 25 in the middle period of acceleration, and the like, the characteristics of the vehicle, the characteristics of the engine 1, and the characteristics of the supercharging system for the internal combustion engine For example, it may be calculated experimentally, empirically, mathematically or theoretically, or using a simulation. Based on this table and the calculated value, the ECU 30 sets the drive signal value of the flow rate adjusting electromagnetic valve 25 and supplies the drive signal to the flow rate adjusting electromagnetic valve 25.

  Further, when the flow rate of the auxiliary compressed air is reduced by making the opening area of the flow rate adjusting electromagnetic valve 25 smaller than the pipe area of the air assist pipe 26, the rotational speed of the exhaust turbine 11 (and further supercharging) It is preferable to reduce the opening area of the flow rate adjusting solenoid valve 25 so that the pressure does not overshoot. In other words, for example, the engine 1 is in an accelerated operation in which the engine is fully loaded by depressing the accelerator pedal strongly from a steady operation state of an arbitrarily low rotational speed between 1000 rpm and 1500 rpm and a low load of 2/5 or less. , The flow rate adjusting solenoid valve 25 is set so that the rotational speed of the exhaust turbine 11 does not exceed the steady rotational speed (that is, the steady turbo rotational speed) of the exhaust turbine 11 when the auxiliary compressed air is not sprayed onto the exhaust turbine 11. It is preferable to reduce the opening area.

  For example, when it is determined that the rotational speed of the exhaust turbine 11 can exceed the steady rotational speed after the vehicle starts accelerating, the rotational speed of the exhaust turbine 11 is equal to or lower than the steady rotational speed. The flow rate of the auxiliary compressed air is decreased so as to maintain the pressure. In other words, after it is determined that the rotation speed of the exhaust turbine 11 may exceed the steady rotation speed after the acceleration of the vehicle is started, it may be determined that the acceleration is in the middle period thereafter. Good (that is, it may be determined that the acceleration is in the early stage). And when there is no possibility that the rotation speed of the exhaust turbine 11 exceeds the steady rotation speed, the flow rate of the auxiliary compressed air is increased again. In other words, after once reducing the flow rate of the auxiliary compressed air, if there is no possibility that the rotational speed of the exhaust turbine 11 exceeds the steady rotational speed, it may be determined that the subsequent period is the later stage of acceleration (that is, Until then, it may be determined as the mid-acceleration). That is, the distinction between the initial period, the middle period, and the latter period of the predetermined period in the present invention is not necessarily defined directly by the unit of “time”, but may be performed based on, for example, the rotational speed of the exhaust turbine 11.

  Here, the actual rotational speed of the exhaust turbine 11 and the flow rate of the auxiliary compressed air will be described with reference to FIGS. 4 and 5. FIG. 4 is a graph conceptually showing the time change of the rotational speed of the exhaust turbine 11 and the flow rate of the auxiliary compressed air by the supercharging system for the internal combustion engine according to this embodiment, and FIG. 5 is a comparative example. The rotational speed of the exhaust turbine 11 and the auxiliary compression by the supercharging system for the internal combustion engine (that is, the supercharging system for the internal combustion engine in which the flow rate of the auxiliary compressed air is not adjusted in the early acceleration period, the middle acceleration period and the late acceleration period as described above) It is a graph which shows notionally the time change of the flow rate of air.

  As shown in the lower part of FIG. 4, the flow rate of the auxiliary compressed air is maintained at the maximum flow rate for a while after the vehicle starts acceleration (that is, during the initial stage of acceleration). Thereafter, the flow rate is less than the maximum flow rate during the middle acceleration period, and the maximum flow rate state is maintained in the later acceleration period.

  Corresponding to the flow rate of this auxiliary compressed air, as shown on the upper side of FIG. 4, the rotational speed of the exhaust turbine 11 increases smoothly at the same time as the acceleration of the vehicle is started. More specifically, the rotational speed of the exhaust turbine 11 increases smoothly while maintaining a state equal to or lower than the steady rotational speed of the exhaust turbine 11.

  On the other hand, as shown in the lower side of FIG. 5, in the internal combustion engine supercharging system according to the comparative example, it is assumed that the flow rate of the auxiliary compressed air is always constant. In this case, as indicated by the dotted line on the upper side of FIG. 5, the rotational speed of the exhaust turbine 11 is in a state exceeding the steady rotational speed of the exhaust turbine 11 (that is, an overshoot state) in the middle period of acceleration. This is not preferable from the viewpoint of the stability of the engine 1 or the supercharging system for the internal combustion engine.

  The lower graph in FIG. 5 shows a graph in which the flow rate of the auxiliary compressed air is constant even in the later stage of acceleration, but in reality, a large amount of auxiliary compressed air is injected into the exhaust turbine 11 from the initial stage of acceleration to the middle stage of acceleration. Therefore, the amount of auxiliary compressed air accumulated in the pressure accumulating tank 21 decreases, and as a result, the flow rate of auxiliary compressed air may inevitably decrease in the latter half of acceleration.

  However, in the present embodiment, first, the acceleration of the vehicle is started because the auxiliary compressed air flow rate immediately after the acceleration of the vehicle is started (that is, in the initial stage of acceleration) can be maintained at the maximum flow rate. The turbo lag immediately after being performed can be improved. Further, after a while after the acceleration of the vehicle is started (that is, during the middle period of acceleration), the flow rate of the auxiliary compressed air is decreased, so that there is little or no possibility that the rotational speed of the exhaust turbine 11 increases excessively. Further, after a while after the flow rate of the auxiliary compressed air is reduced (that is, in the latter half of the acceleration), the flow rate of the auxiliary compressed air is increased again. For example, the rotational speed of the exhaust turbine 11 in the latter half of the acceleration is increased. Can do. In particular, since the flow rate of the auxiliary compressed air is once decreased in the middle stage of acceleration, the possibility that the amount of the auxiliary compressed air accumulated in the pressure accumulating tank 21 is reduced in the late stage of acceleration can be suitably prevented. In this way, the predetermined period after the vehicle starts accelerating is divided into three stages, the initial stage of acceleration, the middle stage of acceleration, and the late stage of acceleration, and the flow rate of auxiliary compressed air in the middle stage of acceleration is subsidized in the early stage of acceleration and late stage of acceleration. By reducing the flow rate of compressed air, the rotational speed of the exhaust turbine 11 can be increased smoothly or stably, and the rotational speed of the exhaust turbine 11 can be stabilized. Furthermore, the auxiliary compressed air accumulated in the pressure accumulating tank 21 can be used efficiently and effectively. Thus, the stability of the internal combustion engine supercharging system can be improved.

  In the upper graph of FIG. 5, for reference, the rotational speed of the exhaust turbine 11 when the auxiliary compressed air is not supplied is indicated by a one-dot chain line.

  In the above-described embodiment, the flow rate adjusting electromagnetic valve 25 has been described as a specific example of the “adjusting means”. However, it is not always necessary to be a solenoid valve, and the flow rate of the auxiliary compressed air can be adjusted. If it is, it can be used instead of the flow rate adjusting electromagnetic valve 25. Furthermore, if it is a structure which can adjust the flow volume of the auxiliary compressed air which flows through air assist piping even if it is not a valve, it can be used instead of the flow volume adjustment electromagnetic valve 25. FIG.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. The feeding system is also included in the technical scope of the present invention.

It is a block diagram which shows notionally the basic composition of the embodiment concerning the supercharging system for internal-combustion engines concerning this embodiment. It is a flowchart which shows notionally the flow of operation | movement of the supercharging system for internal combustion engines which concerns on this embodiment (specifically, adjustment operation | movement of the flow volume of the auxiliary compressed air sprayed from an accumulator tank to an exhaust turbine). It is sectional drawing which shows the cross section of a flow volume adjustment solenoid valve and air assist piping. It is a graph which shows notionally the time change of the number of rotations of an exhaust turbine by the supercharging system for internal combustion engines concerning this embodiment, and the flow volume of auxiliary compressed air. The number of revolutions of the exhaust turbine and the auxiliary compressed air by the supercharging system for the internal combustion engine according to the comparative example (that is, the supercharging system for the internal combustion engine in which the flow rate of the auxiliary compressed air is not adjusted separately in the early acceleration period, the middle acceleration period, and the late acceleration period) It is a graph which shows notionally the time change of the flow rate of.

Explanation of symbols

1 Engine 3 Exhaust Manifold 4 Intake Manifold 11 Exhaust Turbine 12 Compressor 13 Rotary Shaft 14 Air Cleaner 15 Intercooler 21 Accumulation Tank 22 Check Valve 23 Auxiliary Compressed Air Piping 24 Auxiliary Compressed Air Supply Device 25 Flow Control Solenoid Valve 26 Air Assist Piping 30 ECU

Claims (4)

A supercharger comprising an exhaust turbine;
An accumulator tank for supplying auxiliary air to the exhaust turbine;
Adjusting means for adjusting the flow rate of the auxiliary air supplied to the exhaust turbine from the pressure accumulation tank;
In the predetermined period after the vehicle starts accelerating, the adjusting means is configured so that the flow rate in the middle period of the predetermined period is greater than 0 and smaller than the flow rates in the initial period and the late period of the predetermined period. A supercharging system for an internal combustion engine, comprising: control means for controlling the engine.   The supercharging system for an internal combustion engine according to claim 1, wherein the adjusting means is a valve having a variable opening area provided in a pipe connecting the exhaust turbine and the pressure accumulating tank.   The said control means controls the said adjustment means so that the rotation speed of the said exhaust turbine may become below a predetermined rotation speed in the middle period of the said predetermined period at least. The supercharging system for internal combustion engines described in 1.   The supercharging system for an internal combustion engine according to claim 3, wherein the predetermined rotational speed is a steady rotational speed of the exhaust turbine when the auxiliary air is not supplied.

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