JP2016188607A - Internal combustion engine and supercharging method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine and a supercharging method for the same capable of: executing supercharging assistance when a vehicle is started or accelerated by using compressed air accumulated while the vehicle is decelerated; curbing degradation of fuel efficiency, output performance and exhaust gas performance of the engine due to the deterioration in a combustion state caused by insufficient air when the vehicle is started or accelerated; improving the fuel efficiency; and reducing a harmful component in exhaust gas.SOLUTION: An internal combustion engine comprises: a compressed air storage system which stores compressed air Ap in an air tank 22 by driving an air compressor 21 when a vehicle is in a decelerating state; and a supercharging assist system. The supercharging assist system has: a supercharging assist supercharger 24 which is installed in an intake passage 12 where a compressor 16a of a turbocharger 16 is arranged with an air motor 23, connected to the supercharging assist supercharger 24 through a shaft, driven by the compressed air Ap from the air tank 22; a bypass passage 25 which bypasses the supercharging assist supercharger 24; and a passage on-off valve 26 which directs an intake flow to either the supercharging assist supercharger 24 or the bypass passage 25.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle equipped with an internal combustion engine having a turbo-type supercharging system, wherein a supercharging auxiliary device additionally arranged in series with the turbo is operated by effectively using compressed air produced at the time of deceleration of the vehicle. The present invention relates to an internal combustion engine and a supercharging method for an internal combustion engine that contribute to the improvement of exhaust gas.

  In recent years, exhaust gas regulations for internal combustion engines such as diesel engines mounted on vehicles such as trucks and buses have become stricter year by year. In order to cope with this, the technology of downsizing by the equipment of the turbo-type supercharging system or the reduction of the displacement of the internal combustion engine has been adopted.

  In this turbo-type supercharging system, one or two or more turbo-type superchargers are attached, and the turbocharger turbine is rotationally driven using the energy of the exhaust gas of the internal combustion engine. A compressor driven by a turbine compresses the intake air to increase the amount of air supplied into the cylinder. As a result, engine performance is improved. Further, in the high output by reducing the displacement of the internal combustion engine, the fuel consumption is improved by reducing the friction per unit output.

  However, the exhaust gas performance evaluation method of the internal combustion engine has been changed from the conventional steady test mode to the transient test mode in which rapid start and acceleration are repeated, and the exhaust gas performance at the time of transition has become important. . On the other hand, in an internal combustion engine with high engine output and small displacement, it is not possible to demonstrate sufficient exhaust gas performance or engine performance due to a delay in the response of the turbo, etc. during transient exhaust gas performance tests or at the start of the engine. There is a problem that the target performance may not be achieved.

  In this connection, the mass inertial energy during braking is stored in the inertial rotation of the flywheel, or the braking force during braking is generated using a compressor other than the turbocharger. In order to improve the turbocharger operation delay when the vehicle starts acceleration or acceleration from low speed, the compressed air is injected into the auxiliary turbine blade with compressed air to assist the rotation of the turbo. There has been proposed a regenerative brake that obtains a rapid rotation increase of a turbocharger by, for example, jetting and pressurizing air into an intake pipe (for example, see Patent Document 1).

  However, in this regenerative brake configuration, the compressor is operated with the inertial force at the time of deceleration, but there is a problem that the reduction ratio is very large and it is difficult to establish the structure, and an auxiliary turbine is attached to the turbo. For the purpose of improving, the installation of an auxiliary turbine significantly reduces the normal turbo efficiency that does not use the auxiliary turbine, and this is also difficult to establish as a performance and structure.

  Also, the main air flow path with the main impeller (compressor) of the turbocharger and the sub air flow path with the sub impeller (compressor) driven by the air motor are arranged in parallel by branching the intake passage In addition, a supercharger for an automobile engine has been proposed in which an air charge cooler is disposed in the intake passage after merging and the air motor is driven by high-pressure refrigerant gas discharged from a compressor of a vapor compression refrigerator (for example, Patent Document 2). reference).

  However, since this supercharger for an automobile engine selects and uses either the main air flow path or the sub air flow path, the sub air flow path is selected when the amount of exhaust gas rotating at a low speed is small. When the air motor is activated, if the damper (switching valve) arranged at the junction is switched to switch the flow path, the outlet side of the main impeller (compressor) is completely closed, so the turbocharger is in a surge state There is a problem that the turbocharger is damaged. Moreover, since the turbo and the air motor are parallel circuits, the driving force of the air motor becomes larger than when the turbo motor and the air motor are arranged in series, and there is a problem that it is difficult to obtain an effective fuel efficiency improvement effect. Further, since this compressor operation does not operate by effectively utilizing the time of deceleration or the like, it is expected that the fuel consumption will not be improved depending on the driving loss amount.

  On the other hand, the present inventor obtains the actual fuel injection amount to be injected into the cylinder of the internal combustion engine. When the actual fuel injection amount increases, it is determined that the engine is in the acceleration state, and when it is constant, the engine steady state. It is determined that the engine is in the engine deceleration state, and when it is reduced or zero, the combination of these three engine states and the pressure state in the air tank allows the production and stop of production of compressed air by the air compressor. The optimization of the air compressor control of the internal combustion engine to control is proposed (for example, refer patent document 3). In this internal combustion engine, high-pressure air is accumulated with high efficiency by operating the air compressor mainly when decelerating. Electric power and engine power are not used for accumulating compressed air. It has no effect of deterioration.

  In addition to the turbocharger system, the inventor provides a mechanical supercharger that is driven by the power of the internal combustion engine via a clutch in the air supply passage to allow the air flow to the intake manifold side. In an internal combustion engine having a stop valve and having a bypass passage that bypasses the mechanical supercharger, each target value calculated based on the engine speed and the fuel injection amount of the internal combustion engine at the supercharging pressure and the intake air amount An internal combustion engine has been proposed in which a clutch is connected to perform supercharging with a mechanical supercharger so that each measured value becomes each target value when the value is small (see, for example, Patent Document 4). This internal combustion engine has a system structure for detecting an engine supercharging amount deficiency and various states at the time of start and acceleration, and a system structure for operating a mechanical supercharger efficiently.

Japanese Patent Laid-Open No. 08-175216 Japanese Utility Model Publication No. 63-112228 JP 2012-1032 A JP 2011-111929 A

  In recent years, there is a tendency to adopt a technology that aims to improve fuel efficiency by reducing friction per unit output by increasing engine power by reducing the engine size (displacement) aiming at improving fuel efficiency. At the same time, however, fuel consumption and exhaust gas have deteriorated due to a decrease in engine displacement at the time of severe start and acceleration. Adopting a turbocharging system using a turbo to counter this is a trend, but there are problems due to a delay in the response of the turbo Remains.

  In view of the above, the inventor of the present invention has a compressed air storage system that does not use electric power or engine power for an internal combustion engine including a turbocharger system having at least one turbocharger, Combining a system that detects engine supercharging amount and various conditions during start-up and acceleration and an air motor-driven supercharger that is provided in series with the turbocharger compressor on the intake line. When starting or accelerating a vehicle equipped with an engine, the turbocharger is driven by compressed air from the compressed air accumulation system to assist supercharging, i.e., supercharging assist, thereby reducing air shortage at the time of starting or accelerating. It has been found that the output performance and exhaust gas performance can be prevented from deteriorating due to the deterioration of combustion due to the combustion deterioration, and that exhaust gas components can be reduced and fuel consumption can be improved.

  An object of the present invention is to provide an auxiliary supercharger that operates using compressed air accumulated during deceleration when starting and accelerating a vehicle equipped with an internal combustion engine having a turbocharger system. By arranging and operating in series, the engine is supercharged to help prevent engine output performance deterioration and exhaust gas performance deterioration due to deterioration of the combustion state due to air shortage at the time of vehicle start and acceleration Therefore, it is possible to provide an internal combustion engine and a supercharging method for the internal combustion engine that can improve fuel consumption and reduce exhaust gas components.

  In order to achieve the above object, an internal combustion engine of the present invention is an internal combustion engine having a turbocharging system, which includes an air compressor and drives the air compressor in a decelerating state so that the compressed air is supplied to an air tank. It has a compressed air storage system for storing and a supercharging system for supercharging assistance, and the supercharging assistance supercharger of the supercharging assistance supercharging system is provided in an intake passage in which a compressor of a turbo type supercharging system is arranged. And an air motor driven by compressed air from the air tank, a detour bypassing the supercharge assisting supercharger, a flow of passing an intake air flow to the supercharge assist supercharger, and the detour A supercharging assist system having a flow path switching mechanism for switching to a flow through the air flow.

  According to this configuration, when there is a possibility that turbo lag may occur in the turbo-type supercharging system, supercharging assistance can be performed with the supercharging assist supercharger driven by compressed air, so that turbo lag can be avoided. Therefore, it is possible to prevent deterioration of engine output performance due to deterioration of the combustion state caused by air shortage at the time of start or acceleration of a vehicle equipped with this internal combustion engine, improve fuel efficiency, and reduce exhaust gas components.

  Furthermore, since the supercharger for supercharging assistance is driven by an air motor that rotates using the compressed air obtained by the charge operation at the time of deceleration, supercharging assistance is performed without consuming electric power or fuel and adversely affecting fuel consumption. Can do. This supercharging assistance is a supercharging assistance for a very short time to avoid turbo lag, for example, between 0 seconds and 3 seconds, the consumption flow rate of compressed air is very small, and the compressed air consumption balance is also established during vehicle operation. doing.

The proposed system is provided with a detour having a flow path switching mechanism. Air boost from normal operation Turbo not operate the supercharging assisting turbocharger prevents deterioration in fuel efficiency due to pressure loss in passing through the bypass passage without passing through the supercharger auxiliary supercharger. On the other hand, in the state where the supercharger for supercharging assistance is activated, the intake air supercharged by the supercharger for supercharging assistance flows back to the upstream side of the supercharger for supercharging assistance via this bypass. In order to prevent this, a switching mechanism (check valve) is provided on the way.

The detour has proposed two types of arrangement methods. Supercharging assisting supercharger and the detour having a switching mechanism constituting provided on the downstream side of the compressor of the supercharging auxiliary supercharger intake air supercharged by the supercharger auxiliary turbocharger engine direct Good supercharging response can be ensured by entering the cylinder. On the other hand, the case of providing a bypass passage supercharging auxiliary supercharger with a supercharged auxiliary supercharger and switching mechanism on the upstream side of the compressor of the supercharging assisting turbocharger, slightly to the former arrangement Although there is a delay in the supercharging response, the effect of supercharging assistance can be obtained, so both systems are proposed.

  Note that an air compressor (air compressor) used to obtain compressed air is generally operated by a driving force extracted from an output shaft of an internal combustion engine by a gear, a belt, or the like, but is operated by other methods. However, the deceleration charge system shown in the previous report (see Patent Document 3) is required.

  As a control system algorithm, when the control device for controlling the internal combustion engine determines that the operating state of the internal combustion engine is in a deceleration state, the air compressor is actively operated to accumulate compressed air in the air tank, On the contrary, when it is determined that the vehicle equipped with the internal combustion engine starts or accelerates, the supercharger auxiliary turbocharger is driven by the compressed air accumulated in the air tank, and a predetermined supply time or experimental data is used. The driving of the supercharger for supercharging assistance is stopped by a control stop instruction transmitted by the constructed control program system (see Patent Document 4), and an effective effect for improving fuel efficiency is obtained.

  That is, supercharging assistance can be performed without using electric power or fuel by storing the compressed air in the air tank with the regenerative energy of the internal combustion engine when in the deceleration state. Therefore, supercharging assistance can be performed without adversely affecting fuel consumption. In addition, when there is a possibility that turbo lag may occur in the turbo-type supercharging system, this supercharging assistance can avoid the turbo lag, and the deterioration of the engine output performance and the exhaust gas performance due to the deterioration of the combustion state due to air shortage Deterioration can be prevented.

According to the internal combustion engine and the supercharging method of the internal combustion engine of the present invention, a supercharging system for supercharging assistance that is operated using compressed air accumulated during deceleration of a vehicle equipped with the internal combustion engine is provided at the time of starting and acceleration of the vehicle. Sometimes a turbocharger for supercharging assistance is placed and operated in series with a compressor of a turbocharger to assist supercharging of the internal combustion engine, and the combustion state deteriorates due to air shortage at start-up or acceleration The engine output performance and the exhaust gas performance can be prevented from being deteriorated by reducing the exhaust gas component and improving the fuel consumption.

It is a figure showing composition of an internal-combustion engine of a 1st embodiment concerning the present invention. It is a figure which shows the structure of the internal combustion engine of 2nd Embodiment which concerns on this invention.

  Hereinafter, an internal combustion engine and a supercharging method for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIG. FIGS. 1 and 2 show the contents of the proposed supercharging assist system arranged upstream or downstream of the turbo provided in the internal combustion engine.

  The internal combustion engine 10A according to the first embodiment of the present invention includes an engine body 11, an intake passage 12, an exhaust passage 13, and an EGR passage 14.

  In the intake passage 12 connected to the intake manifold 11a of the engine body 11, an air cleaner 15, a compressor 16a of a turbocharger 16, and an air charge cooler 17 are provided in this order from the upstream side. Further, in the exhaust passage 13 connected to the exhaust manifold 11b of the engine body 11, a turbine 16b of the turbocharger 16 is provided in order from the upstream side. The EGR passage 14 is provided by connecting the intake manifold 11a and the exhaust manifold 11b, and the EGR passage 14 is provided with an EGR cooler 18 and an EGR valve 19 in order from the upstream side. Note that this order is reversed, and the EGR valve 19 and the EGR cooler 18 can be used in this order from the upstream side.

  In the present invention, a compressed air storage system having an air compressor (air compressor) 21 driven by the internal combustion engine 10A and an air tank 22 for storing the compressed air Ap compressed by the air compressor 21 is provided. Is done. The air compressor 21 is preferentially driven when the operating state of the internal combustion engine 10A is in a decelerating state. That is, during the deceleration state, the first on-off valve 22 a is opened, the second on-off valve 22 b is closed, and the air compressor 21 is driven to store the compressed air Ap in the air tank 22. In addition, the air compressor (air compressor) 21 is the content of the existing technique generally attached to the large commercial vehicle.

  Further, in the present invention, an air motor 23 driven by the compressed air Ap from the air tank 22, a supercharge assisting supercharger 24 driven by the air motor 23, and a bypass 25 having a passage opening / closing valve 26 disposed therein. It is comprised with the supercharging assistance system which has. The air motor 23 and the supercharger auxiliary supercharger 24 are connected by a shaft, and the air motor 23 is a motor that rotates with air having a plurality of wings inside and is currently mass-produced in a wide range. It is a thing. The passage opening / closing valve 26 functions as a flow path switching mechanism that switches the flow of intake air in the intake passage 12 between a flow through the auxiliary supercharger 24 and a flow through the bypass 25, and a mechanism that is electrically controlled, Even a butterfly type that operates by differential pressure without special control can be established. In the latter case, when the supercharge assisting supercharger 24 does not operate, the passage opening / closing valve 26 is automatically opened by the negative pressure from the compressor 16a of the engine 11 and the turbocharger 16, and conversely, the supercharge assisting supercharger. In a state where 24 is operated, it functions as a system that is mechanically closed by the pressure difference between the outlet pressure of the supercharger for supercharging assistance 24 and the pressure of the bypass 25.

  When starting or accelerating a vehicle equipped with the internal combustion engine 10A, that is, when it is determined that supercharging assistance is necessary in a transient state involving a sudden increase in the engine load or engine speed of the internal combustion engine 10A. The first on-off valve 22a is closed, the second on-off valve 22b is opened, the compressed air Ap is supplied from the air tank 22 to drive the air motor 23, and the air motor 23 is used to supercharge the supercharge assist. The charger 24 is driven to perform supercharging assistance (supercharging assistance).

  In the internal combustion engine 10A of the first embodiment, as shown in FIG. 1, the supercharge assisting supercharger 24 and the bypass circuit 25 having the passage opening / closing valve 26 are provided on the downstream side of the compressor 16a. In the internal combustion engine 10B of the second embodiment, as shown in FIG. 2, the bypass 25 having the auxiliary supercharger 24 and the passage opening / closing valve 26 is provided on the upstream side of the compressor 16a.

  With this configuration, in the internal combustion engine 10A according to the first embodiment, the intake air supercharged by the supercharging assisting supercharger 24 enters the cylinder without passing through the compressor 16a, so that it can be supercharged quickly. The sucked intake air can be supplied into the engine cylinder. On the other hand, in the internal combustion engine 10B according to the second embodiment, the intake air supercharged by the supercharging assist supercharger 24 passes through the compressor 16a and then enters the engine cylinder. However, both of the advantages of the present invention can be ensured.

  The control device 40 for controlling the internal combustion engines 10A and 10B includes an intake air amount sensor (MAF) 31, a supercharging pressure sensor 32, an engine speed sensor 33, a tank air pressure sensor 34, a fuel injection nozzle disposed in the intake passage 12. (With control feedback) 35, etc., starting the control of the fuel injection nozzle, turbo type turbocharger 16, EGR valve 19, air compressor 21, first on-off valve 22a, second on-off valve 22b, the air motor 23, the supercharging assisting supercharger 24, the passage opening / closing valve 26, and the like are controlled.

  In the present invention, when it is determined that the vehicle on which the internal combustion engines 10A and 10B are mounted is in a decelerating state, the control device 40 operates the air compressor 21 to accumulate the compressed air Ap in the air tank 22 and When it is determined that a vehicle equipped with 10A and 10B starts or accelerates, the supercharger 24 for supercharging assistance is driven by the compressed air Ap accumulated in the air tank 22, and the operating state is programmed in advance (preset At the time of acceleration determination exceeding the engine load or the engine speed threshold value, and when the engine is separated from the target engine boost set in advance from the test result), or the pressure of the compressed air Ap is set in advance When the pressure becomes equal to or lower than the lower limit pressure, control is performed to stop the driving of the supercharging assisting supercharger 24 by the compressed air Ap. It is.

  The supercharging method for an internal combustion engine according to the embodiment of the present invention is a supercharging method for an internal combustion engine having a turbo-type supercharging system. The air compressor 21 is operated in a decelerating state to supply compressed air Ap to an air tank. 22, and when starting or accelerating a vehicle equipped with the internal combustion engines 10 </ b> A and 10 </ b> B, the supercharging assisting supercharger 24 disposed in the intake passage 12 in series with the compressor 16 a of the turbocharging system. Is driven by compressed air Ap from the air tank 22 to assist supercharging.

  According to the internal combustion engines 10A and 10B and the internal combustion engine supercharging method configured as described above, supercharging for supercharging assistance that is driven by the compressed air Ap when turbo lag may occur in the turbocharging system. Since the turbocharging can be avoided by this supercharging assistance, a turbo lag can be avoided by the supercharging assistance, and the engine output performance deteriorates due to the deterioration of combustion due to air shortage at the time of start or acceleration of a vehicle equipped with this internal combustion engine. Deterioration of exhaust gas performance can be prevented, fuel efficiency can be improved, and exhaust gas components can be reduced.

  Furthermore, since the supercharger 24 for supercharging assistance is driven by the air motor 23 using compressed air Ap, supercharging assistance can be performed without using electric power or fuel, and supercharging without adversely affecting fuel consumption. Can assist. This supercharging assistance is a supercharging assistance for a very short time to avoid turbo lag, for example, between 0 seconds and 3 seconds, the consumption flow rate of compressed air is very small, and the compressed air consumption balance is also established during vehicle operation. doing.

  When the supercharging assistance is not performed by the bypass 25 and the passage opening / closing valve 26, the supercharging assistance is performed by making the flow of the intake air flow to the bypass 25 and bypassing the supercharging assisting supercharger 24. It is possible to prevent an increase in distribution resistance due to the turbocharger 24 for use. When supercharging assistance is performed, the bypass 25 is closed by closing the passage opening / closing valve 26, and the intake air supercharged by the supercharger 24 for supercharging assistance is supercharged via the bypass 25. Backflow to the upstream side of the auxiliary supercharger 24 can be prevented.

  Further, when the engine is in a deceleration state, the compressed air Ap is stored in the air tank 22 with the regenerative energy of the internal combustion engines 10A and 10B, so that supercharging assistance can be performed without using electric power or fuel, which adversely affects fuel consumption. Supercharging assistance can be done without affecting.

10A, 10B engine (internal combustion engine)
11 Engine body 11a Intake manifold 11b Exhaust manifold 12 Intake passage 13 Exhaust passage 14 EGR passage 15 Air cleaner 16 Turbocharger 16a Compressor 16b Turbine 17 Air charge cooler 18 EGR cooler 19 EGR valve 21 Air compressor 22 Air tank 22a First on-off valve 22b Second on-off Valve 23 Air motor 24 Supercharger for supercharging assistance 25 Detour circuit 26 Passage opening / closing valve 31 Intake amount sensor (MAF)
32 Supercharging pressure sensor 33 Engine speed sensor 34 Tank air pressure sensor 35 Fuel injection nozzle (with control feedback)
40 Controller Ap Compressed air

Claims (4)

  An internal combustion engine having a turbo-type supercharging system is provided with a compressed air storage system for storing the compressed air in an air tank by driving the air compressor when the vehicle is in a decelerated state and a supercharging system for supercharging assistance. A supercharging assisting supercharger of the supercharging assisting system is provided in an intake passage in which a compressor of the turbocharging supercharging system is disposed, and is driven by compressed air from the air tank; And a detour that bypasses the supercharger for supercharging assistance, and a flow path switching mechanism that switches a flow of intake air to a flow that passes through the supercharger for supercharging assistance and a flow that passes through the detour An internal combustion engine comprising the system.   The internal combustion engine according to claim 1, wherein the supercharge assisting supercharger, the bypass, and the flow path switching mechanism are provided on the downstream side of the compressor.   When the control device for controlling the internal combustion engine determines that the operating state of the internal combustion engine is in a deceleration state, the air compressor is operated to accumulate compressed air in the air tank, and the internal combustion engine is mounted. When it is determined that the vehicle is starting or accelerating, the turbocharger for supercharging assistance is driven by the compressed air accumulated in the air tank, and the acceleration determination exceeds a preset engine load or engine speed threshold value. In addition, when the state below the preset target engine boost is released, or when the pressure of the compressed air in the air tank falls below a preset lower limit pressure, the supercharging with the compressed air is performed. The internal combustion engine according to claim 1, wherein the internal combustion engine is configured to perform control to stop driving of the auxiliary supercharger.   In a supercharging method of an internal combustion engine having a turbocharging system, the air compressor is operated in a decelerated state to accumulate compressed air in an air tank, and when starting or accelerating a vehicle equipped with the internal combustion engine, A supercharging system for an internal combustion engine, wherein a supercharging assisting supercharger disposed in an intake passage in series with a compressor of a turbo charging system is driven by compressed air from the air tank to assist supercharging. Method.

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