JP6209989B2 - Turbocharged engine - Google Patents

Description

  The present invention relates to an engine with a turbocharger.

  In an engine with a turbocharger, the rotation speed of the turbocharger (turbine and compressor) is detected by a sensor to prevent boost abnormality (supercharging) and turbine damage, and combustion is performed according to the detected value. By performing the control, it is possible to suppress the rotation speed from becoming overspeed. For example, Patent Document 1 discloses a turbocharger with a turbocharger that reduces the fuel injection amount to reduce exhaust energy when the turbocharger rotational speed exceeds a set value, thereby suppressing an increase in turbine rotational speed. An engine is disclosed.

JP-A-5-280385

  In the above system, in general, a detection signal from a sensor is amplified by an amplifier and then taken into an ECU or the like. However, in that case, if the amplifier is arranged in the vicinity of the ECU, noise is mixed in the detection signal between the sensor and the amplifier, and the signal is amplified by the amplifier later, so that the detection accuracy of the rotational speed may be lowered. . In order to suppress this, it is effective to connect the sensor and the amplifier with a cable with noise countermeasures such as electrostatic shielding and electromagnetic shielding. However, in this case, the cable is expensive. This will increase the cost of the wiring structure.

  On the other hand, if the amplifier is arranged in the vicinity of the sensor, the wiring structure can be reduced, but in this case, the amplifier is placed in the vicinity of the turbocharger that is at a high temperature. There is a risk of receiving.

  The present invention has been made in view of the above circumstances, and is a technology that can accurately detect the rotational speed of a turbocharger while suppressing an amplifier from being damaged by heat with an inexpensive configuration. The purpose is to provide.

In order to solve the above-described problems, the present invention provides an engine having a turbocharger that compresses intake air using exhaust energy, and is fixed to a compressor casing of the turbocharger and rotated. A rotational speed sensor for detecting the number, an amplifier for amplifying and outputting a detection signal of the sensor, a cable connected to the rotational speed sensor and the amplifier and routed along a compressor casing, and the turbocharger A fluid circulation member disposed in the vicinity of the compressor and fixed to the compressor casing for circulating a cooling fluid along a predetermined path, and the amplifier circulates the fluid in the vicinity of the turbocharger. It is fixed to the member for use.

According to this configuration, since the amplifier is arranged near the rotation speed sensor, the length of the cable connecting the rotation speed center and the amplifier can be shortened, and the amount of expensive cables with noise countermeasures can be reduced. be able to. The amplifier is disposed in the vicinity of the turbocharger. However, since the amplifier is fixed to the fluid circulation member through which the cooling fluid circulates, the temperature rise is effectively suppressed. Therefore, according to this configuration, it is possible to accurately detect the rotational speed of the turbocharger with an inexpensive configuration and suppressing the amplifier from being damaged by heat. Further, since the amplifier is fixed to the turbocharger via the fluid circulation member, the positional relationship between the amplifier and the rotation speed center can be stably maintained.

  In this configuration, the cooling fluid is engine cooling water for mainly cooling an engine main body including a cylinder block and a cylinder head, and the fluid circulation member is a pipe through which the engine cooling water circulates.

  According to this configuration, an increase in the temperature of the amplifier can be rationally suppressed using engine cooling water.

  In the above configuration, the turbocharger is a variable capacity turbocharger having a movable vane and capable of adjusting the flow rate of exhaust gas flowing into the turbine by the operation of the movable vane. The engine may further include a control device that controls the rotational speed of the turbocharger based on the rotational speed detected by the rotational speed sensor.

  According to this configuration, the rotational speed of the turbocharger can be appropriately controlled based on the rotational speed detected by the rotational speed sensor.

  As described above, according to the turbocharged engine of the present invention, the rotational speed of the turbocharger can be detected with high accuracy while suppressing the thermal damage of the amplifier with an inexpensive configuration. Is possible.

It is the schematic which shows the whole structure of the engine with a turbocharger (diesel engine) concerning this invention. It is a schematic side view of the exhaust side of an engine. It is an A direction arrow directional view of FIG. It is sectional drawing which shows the specific attachment structure of amplifier.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing the overall configuration of a diesel engine to which the present invention is applied. The diesel engine shown in the figure is a four-cycle turbocharged diesel engine mounted on a vehicle as a driving power source.

  An engine body 1 of this diesel engine (hereinafter abbreviated as an engine) is of an in-line multi-cylinder type, and includes a cylinder block 2 having a plurality of cylinders 2a (only one is shown in FIG. 1), and the cylinder block 2 A cylinder head 3, an oil pan 4 that is disposed below the cylinder block 2 and stores lubricating oil, and a cylinder head cover 5 that covers an upper portion of the cylinder head 3.

  A piston 8 is fitted into each cylinder 2a of the engine body 1 so as to be able to reciprocate. A cavity defining the combustion chamber 8a is formed on the top surface of the piston 8.

  The piston 8 is connected to the crankshaft 10 via a connecting rod 9, and the crankshaft 10 rotates around the central axis according to the reciprocating motion of the piston 8.

  The cylinder head 3 is formed with an intake port 12 and an exhaust port 13 that open to the combustion chamber 8a of each cylinder 2a, and an intake valve 16 and an exhaust valve for opening and closing the intake port 12 and the exhaust port 13. 17 is provided.

  The cylinder head 12 is provided with one injector 18 for injecting fuel mainly composed of light oil for each cylinder 2a. The injector 18 is arranged so that the injection port (fuel injection port) provided at the tip of the injector 18 faces the cavity on the top surface of the piston 14, and at an appropriate timing before and after the compression top dead center (at the end of the compression stroke). Fuel is injected toward the combustion chamber 14a.

  In the engine width direction (left-right direction in FIG. 1) orthogonal to the arrangement direction (cylinder row direction) of the cylinders 2a, an intake passage 20 is provided on one side of the engine body 1 so as to communicate with the intake port 12 of each cylinder 2a. The exhaust passage 30 is connected to the other side of the engine body 1 so as to communicate with the exhaust port 13 of each cylinder 2a. That is, intake air from the outside is introduced into the combustion chamber 8a through the intake passage 20 and the intake port 12, and exhaust gas (combustion gas) generated in the combustion chamber 8a is externally supplied through the exhaust port 13 and the intake passage 20. It is supposed to be discharged.

  A turbocharger 60 is provided in the intake passage 20 and the exhaust passage 30.

  The turbocharger 60 includes a compressor 62a disposed in the intake passage 20 and a turbine 62b coupled to the compressor 62a via a coupling shaft and disposed in the exhaust passage 30.

  The turbocharger 60 is driven by exhaust energy and compresses intake air. That is, when high-temperature and high-speed exhaust gas passes through the exhaust passage 30 during the operation of the engine, the turbine 62b of the turbocharger 60 rotates by receiving the energy of the exhaust gas, and is integrated with this through the connecting shaft. The compressor 62a connected to the compressor also rotates at the same time. As a result, the air (intake air) passing through the intake passage 20 is compressed and increased in pressure, and is pumped to each cylinder 2 a of the engine body 1.

  The turbocharger 60 is provided with a rotation speed sensor 65 that detects the rotation speed (in this example, the rotation speed of the compressor 62a) and outputs a detection signal corresponding to the value. The detection signal output from the rotational speed sensor 65 is amplified by an amplifier 66 disposed in the vicinity of the turbocharger 60 and then input to the ECU 70 (corresponding to the control device of the present invention). The rotational speed of the turbocharger 60 is controlled by adjusting the fuel injection amount by the injector 18 in accordance with the signal. Specifically, when the rotational speed of the turbocharger 60 becomes equal to or higher than the set value, the ECU 70 decreases the fuel injection amount by the injector 18 to reduce the exhaust energy, thereby reducing the rotational speed of the turbocharger 60. Suppresses the rise.

  An air cleaner 21 for filtering the intake air is provided at the upstream end of the intake passage 20, and a surge tank 24 is provided near the downstream end of the intake passage 20 (near the engine body 1). Yes. The intake passage 20 downstream of the surge tank 24 is an independent passage branched for each cylinder 2a, and the downstream end of each independent passage is connected to the intake port 12 of each cylinder 2a.

  Between the air cleaner 21 and the surge tank 24 in the intake passage 20, the compressor 62 a of the turbocharger 60 and the throttle valve 23 that can be opened and closed for adjusting the passage sectional area of the intake passage 20 are sequentially arranged from the upstream side. And an intercooler 22 for cooling the air compressed by the compressor 62a. The throttle valve 23 is basically fully opened during operation of the engine or maintained at a high opening degree close thereto, and is closed only when necessary, such as when the engine is stopped, to block the intake passage 20.

  The upstream end of the exhaust passage 30 is an exhaust multi-branch passage including an independent passage continuous to the exhaust port 13 of each cylinder 2a and a collecting portion where the independent passages gather, that is, an exhaust manifold. Although not clarified in FIG. 1, the exhaust manifold is integrally formed inside the cylinder head 3. A collective exhaust port 3a (see FIG. 2) serving as the collective portion is formed on one side of the cylinder head 3, and the exhaust passage 30 is provided so as to communicate with the collective exhaust port.

  On the downstream side of the exhaust manifold in the exhaust passage 30, in order from the upstream side, the turbine 62 b of the turbocharger 60, a plurality of types of exhaust purification devices for removing harmful components in the exhaust gas, and exhaust sound And a silencer 34 for reducing the above.

  As the exhaust purification device, a DOC (oxidation catalyst) 31 and a DPF (diesel particulate filter) 32 are provided in order from the upstream side.

  The DOC 31 is rendered harmless by oxidizing CO and HC in the exhaust gas discharged from the engine body 1. On the other hand, the DPF 32 collects particulates such as soot contained in the exhaust gas discharged from the engine body 1.

  Between the intake passage 20 and the exhaust passage 30, an HP-EGR passage 51 for returning a part of the high-pressure exhaust gas discharged from the engine body 1 to a relatively high pressure portion of the intake passage 20, An LP-EGR passage 55 that recirculates a part of the low-pressure exhaust gas to a relatively low pressure portion of the intake passage 20 is provided.

  The HP-EGR passage 51 connects the intake passage 20 between the throttle valve 23 and the surge tank 24, the exhaust manifold 30, and the exhaust passage 30 between the turbine 62 b of the turbocharger 60. The HP-EGR passage 51 is provided with an openable and closable EGR valve 52 for adjusting the recirculation amount of the exhaust gas to the intake passage 20. On the other hand, the LP-EGR passage 55 connects the intake passage 20 between the air cleaner 21 and the compressor 62a of the turbocharger 60 and the exhaust passage 30 between the DPF 32 and the silencer 34 to each other. The LP-EGR passage 55 is provided with an openable / closable EGR valve 56 for adjusting the recirculation amount of the exhaust gas to the intake passage 20 and an EGR cooler 57 for cooling the recirculated EGR gas with engine coolant. It has been.

  Next, a more specific structure of the engine will be described with reference to FIGS.

  FIG. 2 is a side view of the engine on the exhaust side, and FIG. 3 is a view in the direction of arrow A in FIG. In the following description, the front direction and the rear direction of each part are based on the front and rear of the engine unless otherwise specified, with the arrangement direction (cylinder row direction) of the cylinders 2a being the front and rear direction of the engine. Further, the direction orthogonal to the front-rear direction of the engine is defined as the engine width direction.

  As shown in the figure, a collective exhaust port 3a of the exhaust manifold is formed on a side surface on the exhaust side of the cylinder head 3 of the engine body 1, and the turbocharger is located at a position corresponding to the collective exhaust port 3a. A machine 60 is provided. Although not shown in detail, the turbocharger 60 is a variable capacity turbocharger (VGT) having a plurality of movable vanes, and a plurality of turbochargers 60 are disposed so as to surround the turbine 62b. The turbine efficiency can be changed by operating the movable vane and changing the opening of a nozzle (gap) formed between adjacent movable vanes. In other words, when the flow rate of exhaust gas is small, high supercharging efficiency can be obtained by reducing the nozzle opening degree. On the other hand, when the flow rate of exhaust gas is large, ventilation resistance is reduced by loosening (increasing) the nozzle opening degree. It is possible to increase the supercharging efficiency by reducing.

  A DOC 31 is disposed on the side of the engine body 1 on the exhaust side and on the front side of the turbocharger 60. The EGR valve 56 and the EGR cooler are disposed below the turbocharger 60 and the DOC31. 57 and DPF 32 are arranged.

  The DPF 32 is disposed in the vicinity of the DOC 31 at a position almost directly below the DOC 31. The front end of the DPF 32 is connected to the front end of the DOC 31 via a U-shaped pipe 30a (a part of the exhaust passage 30).

  A main exhaust pipe 30 b (a part of the exhaust passage 30) connected to the silencer 34 is connected to the rear end of the DPF 32. The main exhaust pipe 30b extends slightly diagonally downward from the rear end of the DPF 32 toward the outside in the width direction of the engine body 1.

  An EGR cooler 57 is fixed to a mounting portion (not shown) provided on a rear side surface (that is, a side surface on the side opposite to the DPF 32) of the main exhaust pipe 30b, and an EGR valve is disposed on the rear side of the EGR cooler 57. 56 is fixed.

  Connected to the rear side of the EGR valve 56 is an upstream end portion of an EGR pipe 55 a constituting the LP-EGR passage 55. The downstream end of the EGR pipe 55a is connected to the upstream intake pipe 20a (a part of the intake passage 20). The upstream intake pipe 20 a constitutes the intake passage 20 between the air cleaner 21 and the compressor 62 a of the turbocharger 60, and is connected to the compressor casing 61 a of the turbocharger 60. The EGR pipe 55a is connected to a middle portion of the upstream intake pipe 20a at a position near the connection part between the upstream intake pipe 20a and the compressor casing 61a.

  2 denotes a downstream side intake pipe connected to the compressor casing 61a of the turbocharger 60. The downstream side intake pipe 20 b constitutes the intake passage 20 between the intercooler 22 and the compressor 62 a of the turbocharger 60. Also, reference numeral 58 in the figure is a blow-by gas pipe (passage) 58 for introducing the blow-by gas accumulated in the engine body 1 into the intake passage 20. The blow-by gas pipe 58 connects the cylinder head cover 5 and the upstream intake pipe 20a to each other.

  As shown in FIG. 3, the rotational speed sensor 65 is fixed to the upper part of the compressor casing 61a of the turbocharger 60, and the amplifier 66 is disposed in the vicinity thereof. Specifically, on the rear side of the engine body 1, engine cooling water (hereinafter referred to as cooling water) passing through the engine body 1 (the cylinder block 2 and the cylinder head 3) is supplied to a heater core (not shown) of the air conditioning system. ) And a cooling water pipe 72 (corresponding to the fluid circulation member of the present invention) for guiding the cooling water circulating from the heater core to the engine body 1 side is routed. The cooling water pipe 72 extends in the vertical direction along the compressor casing 61 a in the space between the compressor casing 61 a of the turbocharger 60 and the cylinder block 2. A mounting bracket 76 is fixed to a portion of the cooling water pipe 72 located on the side of the compressor casing 61a by brazing. As shown in FIG. Is fixed with bolts B1 and nuts N1.

  The rotational speed sensor 65 and the amplifier 66 are connected to each other by a cable 67 that is provided with noise countermeasures such as electrostatic shielding and electromagnetic shielding. As shown in FIG. 3, the cable 67 is routed along the lower surface of the compressor casing 61 a and connected to the lower portion of the amplifier 66. A connection cable 68 having a connector 68a is provided on the amplifier 66. This cable 68 is for connecting the amplifier 66 to the ECU 70, and is connected to a relay cable (not shown) via the connector 68a. As a result, the amplifier 66 is connected to the ECU 70 via the relay cable.

  The cooling water pipe 72 is bolted to the compressor casing 61a by a fixing bracket 74 at a position near the mounting bracket 76, as shown in FIG. As with the mounting bracket 76, the fixing bracket 74 is fixed to the cooling water pipe 72 by brazing and is further bolted to the compressor casing 61a.

  According to the engine as described above, since the amplifier 66 is disposed near the rotation speed sensor 65 as described above, the length of the cable 67 connecting the rotation speed sensor 65 and the amplifier 66 can be shortened, The amount of expensive cables with noise countermeasures such as shielding and electromagnetic shielding can be reduced. Although the amplifier 66 is disposed in the vicinity of the turbocharger 60, as described above, since the amplifier 66 is fixed to the cooling water pipe 72 through which the cooling water circulates, the temperature rise is effectively suppressed. For example, during operation of the engine, the temperature of the turbocharger 60 rises to about 160 ° C. However, since the temperature of the cooling water flowing through the cooling water pipe 72 is about 80 ° C., even if the amplifier 66 is heated. The temperature transfer of the amplifier 66 is effectively suppressed by heat transfer from the amplifier 66 to the cooling water pipe 72 (cooling water), and the temperature of the amplifier 66 is suppressed to less than the heat resistant temperature (for example, 120 ° C.).

  Therefore, according to the engine, it is possible to accurately detect the rotational speed of the turbocharger 60 with an inexpensive configuration and while suppressing the amplifier 66 from being damaged by heat. The rotational speed can be appropriately controlled.

  Moreover, since the temperature rise of the amplifier 66 can be suppressed using the existing engine cooling water, it is possible to suppress the amplifier 66 from being damaged by heat with a reasonable configuration.

  Further, according to the engine, since the amplifier 66 is fixed to the turbocharger 60 via the cooling water pipe 72, the positional relationship among the amplifier 66, the cooling water pipe 72, and the turbocharger 60 is stable. Kept. Therefore, there is also an advantage that troubles such as the cable 67 being pinched between the cooling water pipe 72 and the turbocharger 60 due to vibration during traveling can be prevented.

  The engine described above is an example of a preferred embodiment of an engine with a turbocharger according to the present invention, and the specific configuration of the engine can be changed as appropriate without departing from the gist of the present invention. .

  For example, in the above embodiment, the amplifier 66 circulates the cooling water that has passed through the engine body 1 to the heater core of the air conditioning system, and the cooling water pipe 72 that guides the cooling water that circulates from the heater core to the engine body 1 side. Although it is fixed, you may make it fix to piping of cooling water other than this. For example, the amplifier 66 may be fixed to a pipe for supplying cooling water to the EGR cooler 57. Further, since the EGR cooler 57 circulates cooling water therein (an example of the fluid circulation member of the present invention), the amplifier 66 may be fixed to the EGR cooler 57 itself. Further, in addition to fixing the amplifier 66 to the pipe through which the cooling water flows in this way, for example, in the vicinity of the turbocharger 60, route an oil pipe through which the cooling water or the lubricating oil cooled by air cooling circulates, The amplifier 66 may be fixed to the oil pipe. Even with such a configuration, it is possible to enjoy the same operational effects as in the above embodiment.

  Moreover, in the said embodiment, although this invention was applied to the diesel engine, you may apply not only to this but to a gasoline engine.

DESCRIPTION OF SYMBOLS 1 Engine main body 2 Cylinder block 3 Cylinder head 3a Collecting exhaust port 4 Oil pan 5 Cylinder head cover 20 Intake passage 30 Exhaust passage 60 Turbocharger 61a Compressor casing 61b Turbine casing 62a Compressor 62b Turbine 65 Speed sensor 66 Amplifier 70 ECU (control) apparatus)
72 Cooling water piping (fluid circulation member)

Claims (3)

An engine equipped with a turbocharger that compresses intake air using exhaust energy,
A rotational speed sensor fixed to the compressor casing of the turbocharger and detecting the rotational speed;
An amplifier that amplifies and outputs the detection signal of this sensor;
A cable that connects the rotation speed sensor and the amplifier and is routed along the compressor casing;
A fluid circulation member disposed in the vicinity of the turbocharger and fixed to the compressor casing for circulating a cooling fluid along a predetermined path;
The engine with a turbocharger, wherein the amplifier is fixed to the fluid circulation member in the vicinity of the turbocharger. The turbocharged engine according to claim 1,
The cooling fluid is engine cooling water for mainly cooling an engine main body including a cylinder block and a cylinder head, and the fluid circulation member is a pipe through which the engine cooling water circulates. Turbocharged engine. The turbocharged engine according to claim 1 or 2 ,
The turbocharger is a variable capacity turbocharger having a movable vane and capable of adjusting a flow rate of exhaust gas flowing into the turbine by the operation of the movable vane.
The engine further includes a control device that controls the rotational speed of the turbocharger based on the rotational speed detected by the rotational speed sensor.

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