JP2017078396A - Vehicle supercharging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle supercharging system capable of achieving superior energy management for a vehicle mounted with a plurality of superchargers.SOLUTION: A vehicle supercharging system comprises a first supercharger which is an electric supercharger and a second supercharger which is a turbocharger. The vehicle supercharging system is adapted to allow: exhaust gas of an engine to be supplied to a first compressor by exhaust gas supply amount control means; and an electric motor to be regenerated with the first compressor driven by the exhaust gas.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a supercharging system for a vehicle including a supercharger having a compressor configured to be driven by an electric motor.

  Some vehicles equipped with an engine as a driving power source use a supercharger for the purpose of improving output and fuel efficiency. For example, a turbocharger, which is a type of supercharger, includes a turbine provided in an exhaust passage and a compressor provided in an intake passage so as to be driven in conjunction with the turbine, and the turbine is driven by exhaust gas. If it does, supercharging will be performed by the compressor of an intake passage being driven in conjunction. There is also known an electric supercharger that can rotate a compressor provided in an intake passage by using an electric motor that can drive, for example, electric power stored in a battery.

  Patent Document 1 discloses an example of a supercharging system including both a turbocharger and an electric supercharger, and particularly describes that the turbocharger and the electric supercharger are controlled based on the speed of the vehicle. ing.

JP 2004-316558 A

  Since the supercharging efficiency of the turbocharger depends on the flow rate of the exhaust gas, the supercharging efficiency is reduced when the exhaust gas flow rate is small. On the other hand, the electric supercharger can stably achieve good supercharging efficiency by driving electric power without depending on the flow rate of exhaust gas. Therefore, in a supercharging system including a turbocharger and an electric supercharger as in Patent Document 1, in an operating state where the flow rate of exhaust gas is low, the turbocharger whose supercharging efficiency is reduced is stopped, and the electric supercharger By driving, it is possible to prevent a decrease in supercharging efficiency. Thus, the control of the supercharger is important from the viewpoint of vehicle energy management, and further improvement in efficiency is required.

  At least one embodiment of the present invention has been made in view of the above-described problems, and an object thereof is to provide a vehicle supercharging system capable of achieving excellent energy management in a vehicle equipped with a plurality of superchargers. To do.

  In order to solve the above-described problem, a supercharging system for a vehicle according to at least one embodiment of the present invention includes a first supercharger having a first compressor that is provided in an intake passage of an engine and configured to be driven by an electric motor. A second supercharger having a compressor, a turbine provided in an exhaust passage of the engine, and a second compressor provided in the intake passage and configured to be driven in conjunction with the turbine; An exhaust gas supply amount adjusting means capable of adjusting an exhaust gas supply amount of the engine to the first compressor and the turbine, respectively, and driving the first compressor by the exhaust gas supplied by the exhaust gas supply amount adjusting means By doing so, the electric motor is regenerated.

  According to the above configuration, for example, when the first supercharger is in a stopped state, the stopped first compressor is driven by supplying the exhaust gas to the first compressor by the exhaust gas supply amount adjusting means. be able to. Then, when the electric motor connected to the rotating shaft of the first compressor is regeneratively driven, the energy contained in the exhaust gas can be recovered as electric energy, and the energy efficiency of the vehicle can be further improved.

1 is a schematic diagram illustrating an overall configuration of a supercharging system for a vehicle according to at least one embodiment of the present invention. FIG. 2 is a schematic diagram schematically showing intake and exhaust flow paths when the first supercharger is in a stopped state in FIG. 1.

  Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.

  FIG. 1 is a schematic diagram showing an overall configuration of a vehicle supercharging system 1 according to at least one embodiment of the present invention, and FIG. 2 is a flow chart of intake and exhaust when the engine 2 is stopped in FIG. It is a schematic diagram which shows schematically.

  In FIG. 1 and FIG. 2, the flow of intake air is indicated by thin hatching, and the flow of exhaust gas is indicated by dark hatching. In particular, in FIG. 1, in order to show a typical intake air flow of the supercharging system 1, the intake air is branched and introduced into a first intake passage 12 and a second intake passage 14 which will be described later. The flow path when both the supercharger 24 and the second supercharger 26 are driven is shown.

  A vehicle equipped with a supercharging system 1 is provided with an engine 2 as a driving power source. The engine 2 is an internal combustion engine capable of outputting power by burning fossil fuel, and in particular, a four-cylinder diesel engine is illustrated in FIG. The engine 2 mixes fuel supplied from a fuel injection device (not shown) with the intake air taken in from the intake passage 4 and burns it, and discharges exhaust gas from the exhaust passage 6.

The intake passage 4 has an intake port 8 for taking in outside air, and is branched into a first intake passage 12 and a second intake passage 14 starting from a branch point 10 provided on the downstream side thereof. Yes. A valve 18 is provided at the branch point 10, and according to the switching state of the valve 18, intake air introduced from the intake port 8 is one of the first intake passage 12 and the second intake passage 14. Or it is comprised so that inflow into both is possible. The first intake passage 12 and the second intake passage 14 are connected to an intake manifold 16 of the engine 2 after merging at a merging point 15 on the downstream side.
In the example of FIG. 1, the first intake passage 12 and the second intake passage 14 are configured to have a single (common) intake port 8, but the first intake passage 12 and the second intake passage 14 The two intake passages 14 may be provided with independent intake ports.

The exhaust manifold 22 of the engine 2 is provided with an exhaust passage 6 for discharging exhaust gas generated in the engine 2 to the outside. The exhaust gas discharged from the engine 2 is purified by an exhaust purification device installed on the exhaust passage 6 and then discharged to the outside. In FIG. 1, as an exhaust purification device, a diesel particulate filter 42 for collecting particulate matter contained in exhaust gas, and a nitrogen oxide in the exhaust gas is purified by adding a reducing agent such as urea water to the exhaust gas. An SCR system 44 for doing so is illustrated.
In the case where the engine 2 is a gasoline engine, a three-way catalyst may be used as an exhaust purification device.

  The engine 2 includes a first supercharger 24 and a second supercharger 26 for the purpose of improving output and fuel efficiency. The first supercharger 24 is an electric supercharger having a first compressor 28 that can be driven by the electric motor 30. The first compressor 28 is provided in the first intake passage 12, and the first compressor 28 connected to the rotating shaft of the electric motor 30 when the electric motor 30 is driven by the electric power stored in the battery 29. Is configured to be driven.

  The second supercharger 26 is a turbocharger having a turbine 32 provided in the exhaust passage 6 and a second compressor 34 provided in the second intake passage 14. In the second supercharger 26, when the turbine 32 is driven by the exhaust gas of the engine 2, the second compressor 34 is driven in conjunction with the turbine 32 to perform supercharging.

  In the present embodiment, the first compressor 28 and the second compressor 34 are provided in parallel to the engine 2 in the intake passage 4 as described above, but may be configured to be provided in series. Good.

  The operating states of the first supercharger 24 and the second supercharger 26 are controlled based on a control signal from an ECU (Electric Control Unit) which is a control unit of the vehicle, for example. Here, a control example of the first supercharger 24 and the second supercharger 26 will be briefly described.

  Since the first supercharger 24 is an electric supercharger that can operate using the electric power supplied from the battery 29, it is not affected by the flow rate of exhaust gas, and is relatively good at low speeds. Efficiency is obtained. On the other hand, since the second supercharger 26 is a turbocharger that is driven by exhaust gas, the supercharging efficiency is reduced during low-speed traveling where the flow rate of the exhaust gas is relatively small. In view of the difference between the characteristics of the two superchargers, for example, the following control is performed.

  Since the flow rate of the exhaust gas from the engine 2 is relatively small when the vehicle is traveling at a low speed, the first supercharger that is not affected by the flow rate of the exhaust gas is stopped while the second supercharger 26 that has low supercharging efficiency is stopped. By performing supercharging with the device 24, the supercharging efficiency of the entire vehicle can be ensured satisfactorily. On the other hand, when the vehicle is traveling at a high speed, the flow rate of the exhaust gas from the engine 2 is relatively large, so that the second supercharger 26 can obtain good supercharging efficiency. Therefore, by using the second supercharger 26 during high speed traveling, the use of the first supercharger 24 with power consumption is refrained. Thereby, useless power consumption is suppressed and good energy efficiency can be achieved.

  As described above, in the supercharging system 1, there can be many timings at which the first supercharger 24 does not contribute to supercharging depending on the traveling state of the vehicle. While the first supercharger 24 does not contribute to supercharging, as shown in FIG. 2, all the intake air taken in from the intake port 8 by switching the valve 18 is introduced into the second intake passage 14. The At this time, introduction of intake air is prohibited in the first intake passage 12 and is isolated from the second intake passage 14. Under such circumstances, the supercharging system 1 according to the present embodiment achieves further improvement in energy efficiency by effectively utilizing the first supercharger 24 that does not contribute to supercharging with the configuration described below. be able to.

  The supercharging system 1 includes exhaust gas supply amount adjusting means capable of adjusting the exhaust gas supply amount of the engine 2 to the first compressor 28 and the turbine 32, respectively. In the present embodiment, examples of the exhaust gas supply amount adjusting means include a bypass passage 46, a return passage 48, and valves that can be switched to introduce intake air and exhaust gas into these passages.

  The bypass passage 46 is provided so as to connect between the exhaust passage 6 and the first intake passage 12. One end 46 a of the bypass passage 46 is connected to the exhaust passage 6 via the valve 19, and a part of the exhaust gas flowing through the exhaust passage 6 can be introduced by switching the open / close state of the valve 19. .

  Here, the installation position of the valve 19 on the exhaust passage 6 may be arbitrary, but in FIG. In the exhaust passage 6 on the upstream side of the turbine 32, the exhaust pressure is relatively high, so that the exhaust gas can be satisfactorily introduced into the bypass passage 46 as the valve 19 is opened and closed.

  On the other hand, the other end 46 b of the bypass passage 46 is connected to the upstream side of the first compressor 28 in the first intake passage 12. As a result, the exhaust gas introduced through the bypass passage 46 is supplied to the first compressor 28, whereby the first compressor 28 in a stopped state can be driven. When the first compressor 28 is driven, the electric motor 30 connected to the rotating shaft is driven to generate power. The electric power generated by the electric motor 30 is charged in a battery 29 installed in the vehicle. In this way, by introducing a part of the exhaust gas into the first supercharger 24 in the stopped state, the energy contained in the exhaust gas can be recovered as electric energy.

  Incidentally, the other end 46b of the bypass passage 46 is provided with a valve that can be controlled to open and close following the one end 46a, so that the switching of the flow path of the exhaust gas introduced through the bypass passage 46 is made more reliable. Good.

  The exhaust gas after driving the first compressor 28 is returned to the exhaust passage 6 through a return passage 48 provided on the downstream side of the first compressor 28. One end 48 a of the return passage 48 is connected to the downstream side of the first compressor 28 in the first intake passage 12. In the present embodiment, in particular, a valve 50 is provided at one end 48 a of the return passage 48. By opening and closing the valve 50, exhaust gas introduced into the first compressor 28 via the bypass passage 46 is returned to the return passage 48. 48 can be introduced.

  On the other hand, the other end 48 b of the return passage 48 is connected to the downstream side of the turbine 32 in the exhaust passage 6. As described above, exhaust gas having a high pressure is introduced into the bypass passage 46 from the upstream side of the turbine 32, and the return passage 48 is connected to the downstream side of the turbine 32 having a low pressure, so that the differential pressure is determined based on these. Thus, the exhaust gas can be efficiently introduced into the first compressor 28. As a result, power generation by the first compressor 28 is promoted, and electric energy can be efficiently recovered.

  The other end 48b of the return passage 48 is provided with a valve that can be controlled to open and close following the one end 48a, so that the flow of exhaust gas discharged through the return passage 48 can be switched more reliably. Good.

  Thereafter, the exhaust gas returned to the exhaust passage 6 through the return passage 48 is discharged to the outside through the exhaust passage 6 together with the exhaust gas directly discharged from the engine 2.

  As described above, according to the above configuration, when the supercharging by the first supercharger 24 driven by the exhaust gas is in a stopped state, a part of the exhaust gas passes through the bypass passage 46 and the first compressor. 28. As a result, the first compressor 28 in a stopped state is driven by the exhaust gas supplied from the bypass passage 46, and accordingly, the electric motor 30 connected to the first compressor 28 is driven as a generator. In this way, the energy efficiency of the vehicle is improved by recovering the energy of the exhaust gas as electric energy.

DESCRIPTION OF SYMBOLS 1 Supercharging system 2 Engine 4 Intake passage 6 Exhaust passage 8 Intake port 10 Branch point 12 First intake passage 14 Second intake passage 15 Junction point 16 Intake manifold 18, 19, 50 Valve 22 Exhaust manifold 24 First Supercharger 26 Second supercharger 28 First compressor 29 Battery 30 Electric motor 32 Turbine 34 Second compressor 42 Diesel particulate filter 44 SCR system 46 Bypass passage 48 Return passage

Claims (1)

A first supercharger having a first compressor provided in an intake passage of the engine and configured to be drivable by an electric motor;
A turbine provided in an exhaust passage of the engine, and a second supercharger having a second compressor provided in the intake passage and configured to be driven in conjunction with the turbine;
An exhaust gas supply amount adjusting means capable of adjusting an exhaust gas supply amount of the engine to the first compressor and the turbine, respectively.
A supercharging system for a vehicle, wherein the electric motor is regenerated by driving the first compressor with the exhaust gas supplied by the exhaust gas supply amount adjusting means.

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