JP2010127187A - Diesel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diesel engine capable of operating a postprocessing catalyst, while avoiding the inflow of excessive air by a supercharger to an exhaust passage, even when a load of the diesel engine is small. <P>SOLUTION: This diesel engine 1 has an exhaust emission control device 3 and the supercharger 2. The supercharger 2 is composed of a turbine part 13 arranged in the exhaust passage 12, a supply air compressing compressor part 15 arranged in an intake passage 11, and a turbine shaft 14 for connecting the turbine part 13 and the compressor part 15. A hydraulic turbine 16 is journaled by the turbine shaft 14, and a switching valve 20 is arranged in a lubricating oil passage 18 for supplying lubricating oil to the hydraulic turbine 16. When the engine load is low, the lubricating oil is supplied in the inverse direction of the rotating direction of the hydraulic turbine 16, and when the engine load is ordinary, the switching valve 20 is controlled so as to supply the lubricating oil in the same direction as the rotating direction of the hydraulic turbine 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technology for a diesel engine, and more particularly to a technology for a diesel engine including an exhaust purification device.

Conventionally, as a technique for purifying exhaust gas from a diesel engine, it is known to equip an exhaust gas purification apparatus having a post-treatment catalyst in an exhaust passage of the diesel engine. The post-treatment catalyst is composed of, for example, a particulate filter (DPF) that removes particulate matter (PM) in the exhaust gas. The recyclable temperature of the particulate filter is about 300 ° C. or higher.
The post-treatment catalyst is composed of an oxidation catalyst that promotes an oxidation reaction of fuel and raises an exhaust gas temperature, and a continuous regeneration type particulate filter (DPF) installed downstream of the oxidation catalyst. You can also. The activation temperature of the oxidation catalyst is about 300 ° C. or higher.

In addition, the post-treatment catalyst may be composed of an oxidation catalyst that promotes a fuel oxidation reaction and raises an exhaust gas temperature, and a selective reduction NOx catalyst that is installed downstream of the oxidation catalyst. The selective reduction NOx catalyst (SCR) reduces nitrogen oxides (NOx) to nitrogen. For example, urea is supplied from the outside to change to ammonia, and this ammonia reacts with NOx in the exhaust gas. Thus, a urea SCR device that converts NOx to nitrogen is known. The active temperature of the selective reduction NOx catalyst (SCR) is about 350 ° C. or higher.
That is, in order to work the post-treatment catalyst, it is necessary to work at a high temperature of at least 300 ° C. or more. However, in the low load range, the exhaust temperature is low and the post-treatment catalyst does not work.

Therefore, even when the load of the diesel engine is small, a technique is known in which intake or exhaust is throttled by a throttle valve in order to increase the exhaust temperature, or the exhaust temperature is increased by multistage injection after main injection (for example, Patent Document 1).
A diesel engine equipped with a supercharger is also known. The supercharger rotates the turbine on the exhaust passage side, rotates the compressor via a turbine shaft connected to the turbine and the compressor, and compresses the intake air (see, for example, Patent Document 2).
JP 2001-280121 A JP 2006-170060 A

  In a diesel engine equipped with a supercharger, the supercharger supercharges to ensure sufficient air for burning the fuel. However, when the load of the diesel engine is low, excessive air due to supercharging suppresses an increase in gas temperature. This is because if the combustion is performed in a state where the intake air amount is small, the exhaust temperature tends to rise, but since the intake air amount is increased by the supercharger, the exhaust temperature is difficult to rise. Further, exhaust gas expansion may occur in the turbine section, and the exhaust temperature downstream of the turbine may decrease. Due to these causes, the post-treatment catalyst may not work sufficiently. In such a case, for example, if the intake or exhaust is throttled by a throttle valve in order to raise the exhaust temperature, or if the exhaust temperature is raised by multistage injection after the main injection, the fuel efficiency is deteriorated.

  Therefore, in view of such problems, the present invention is a diesel engine capable of operating a post-treatment catalyst while avoiding excessive air from flowing into the exhaust passage even when the load of the diesel engine is small. I will provide a.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, in claim 1, in a diesel engine comprising an exhaust purification device connected to an exhaust passage and a supercharger that compresses intake air in the intake passage, the supercharger is a turbine section provided in the exhaust passage. And a compressor section for supplying and compressing air provided in the intake passage, and a turbine shaft that connects the turbine section and the compressor section. A hydraulic turbine is pivotally supported on the turbine shaft, and lubricating oil is supplied to the hydraulic turbine. When the engine load is low, lubrication oil is supplied in the direction opposite to the direction of rotation of the hydraulic turbine when the engine load is low, and when the engine load is normal, the turbine is In order to promote the rotation of the shaft, the switching valve is controlled so that the lubricating oil is supplied in the same direction as the direction in which the hydraulic turbine rotates.

  In claim 2, in a diesel engine comprising an exhaust purification device connected to an exhaust passage and a supercharger that compresses intake air in the intake passage, the supercharger includes a turbine section provided in the exhaust passage; It is composed of a compressor section for air supply compression provided in the intake passage, and a turbine shaft that connects the turbine section and the compressor section. A hydraulic turbine is supported on the turbine shaft and lubricating oil is supplied to the hydraulic turbine. An open / close valve is provided in the oil passage, and the open / close valve is controlled to supply lubricating oil in a direction opposite to the direction of rotation of the hydraulic turbine in order to suppress the rotation of the turbine shaft when the engine load is low.

  According to a third aspect of the present invention, in a diesel engine comprising an exhaust purification device connected to an exhaust passage and a supercharger that compresses intake air in the intake passage, the supercharger includes a turbine section provided in the exhaust passage; It is composed of a compressor section for air supply compression provided in the intake passage, and a turbine shaft that connects the turbine section and the compressor section. A hydraulic turbine is supported on the turbine shaft and lubricating oil is supplied to the hydraulic turbine. When the engine load is low, lubricating oil is supplied in the direction opposite to the direction of rotation of the hydraulic turbine to suppress the rotation of the turbine shaft. When the engine load is normal, the turbine is In order to promote the rotation of the shaft, the two on-off valves are controlled so as to supply the lubricating oil in the same direction as the direction in which the hydraulic turbine rotates.

  According to a fourth aspect of the present invention, in a diesel engine comprising an exhaust purification device connected to an exhaust passage and a supercharger that compresses intake air in the intake passage, the supercharger includes a turbine section provided in the exhaust passage; It is composed of a compressor section for air supply compression provided in the intake passage, and a turbine shaft that connects the turbine section and the compressor section. A hydraulic turbine is supported on the turbine shaft and lubricating oil is supplied to the hydraulic turbine. When the engine load is low, the opening of the opening adjustment valve is used to supply lubricating oil in the direction opposite to the direction of rotation of the hydraulic turbine so as to suppress the rotation of the turbine shaft. Is controlled.

  According to a fifth aspect of the present invention, a wastegate is provided in the exhaust passage, the wastegate is provided with an inlet on the engine side from the turbine portion of the exhaust passage, and an outlet is provided on the aftertreatment catalyst side with respect to the turbine portion of the exhaust passage. It is a configuration.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, when the load is low, the rotation of the supercharger is suppressed to prevent excessive air supply, and the amount of exhaust gas flowing into the turbine section is restricted to prevent the expansion of exhaust gas, A decrease in exhaust temperature can be prevented. Further, during normal times, more air can be supplied by promoting the rotation of the supercharger.

  In Claim 2, when the load is low, the rotation of the supercharger is suppressed to prevent excessive supply of air, and the amount of exhaust gas flowing into the turbine portion is limited to prevent expansion of exhaust gas, A decrease in exhaust temperature can be prevented. Further, the cost can be reduced because the control is performed with a relatively inexpensive on-off valve.

  In claim 3, when the load is low, the rotation of the supercharger is suppressed to prevent excessive air supply, and the amount of exhaust gas flowing into the turbine portion is restricted to prevent exhaust expansion. A decrease in exhaust temperature can be prevented. Further, the cost can be reduced because the control is performed with a relatively inexpensive on-off valve. Further, during normal times, more air can be supplied by promoting the rotation of the supercharger.

  In claim 4, when the load is low, the rotation of the supercharger is suppressed to prevent excessive supply of air, and the amount of exhaust flowing into the turbine portion is limited to prevent expansion of exhaust, A decrease in exhaust temperature can be prevented. Moreover, the flow rate of the lubricating oil suitable for the load state can be set by controlling the opening degree of the opening degree adjusting valve.

  According to the fifth aspect of the present invention, the exhaust gate can be prevented from expanding and the exhaust temperature from being lowered by opening the waste gate.

Next, embodiments of the invention will be described.
FIG. 1 is a schematic diagram showing the overall configuration of a diesel engine according to an embodiment of the present invention, FIG. 2 is a block diagram showing a control system of a controller, and FIG. 3 shows a relationship between engine load and engine speed. FIG. 4 is a sectional view showing the lubricating oil chamber, FIG. 5 is a sectional view showing the lubricating oil chamber, FIG. 6 is a sectional view showing the lubricating oil chamber, and FIG. 7 is a sectional view showing the lubricating oil chamber.

First, the whole structure of the diesel engine which is one Embodiment of the diesel engine 1 in this invention is demonstrated using FIG.
The diesel engine 1 includes an intake passage 11 for taking in air necessary for fuel combustion, and an exhaust passage 12 for discharging exhaust gas after combustion of fuel. The diesel engine 1 includes a supercharger 2 that compresses intake air in the intake passage 11 and an exhaust purification device 3 that purifies and discharges exhaust gas generated in the diesel engine 1.
The supercharger 2 includes a turbine unit 13, a turbine shaft 14, a compressor unit 15 and the like.
The turbine section 13 is provided in the exhaust passage 12 and is configured to drive the turbine by supplying exhaust to the turbine section 13. The turbine unit 13 is connected to a compressor unit 15 for supplying and compressing air via a turbine shaft 14.

A plurality of rotating blades 16 a are provided in the middle of the turbine shaft 14 so that the hydraulic turbine 16 cannot rotate relative to the turbine shaft 14. The hydraulic turbine 16 and the turbine shaft 14 are provided in a lubricating oil chamber 17. As shown in FIG. 4, the lubricating oil chamber 17 is provided with two lubricating oil inlets 17A and 17B and one lubricating oil outlet 17C. A lubricating oil passage 18 connected to a lubricating oil circuit (not shown) in the diesel engine 1 is connected to the two lubricating oil inlets 17A and 17B, and a middle portion of the lubricating oil passage 18 is shown in FIG. As shown, a switching valve 20 is provided. Specifically, the oil passage 18A is connected to the lubricating oil inlet 17A, the oil passage 18B is connected to the lubricating oil inlet 17B, the oil passages 18A and 18B are connected to the outlet side of the three-way switching valve 20, and the switching valve 20 The inlet is connected to an oil passage 18C, and the oil passage 18C is connected to a lubricating oil pump via a lubricating oil passage formed in a cylinder block or the like. The lubricating oil outlet 17C is configured to return to the oil pan through a lubricating oil passage formed in the cylinder block through the oil passage.
The switching valve 20 is constituted by an electromagnetic valve or the like, and switches the flow direction of the lubricating oil to supply the lubricating oil to either the lubricating oil inlet 17A or 18B. The valve body of the switching valve 20 is A solenoid serving as an actuator to be switched is connected to the controller 41.

The exhaust purification device 3 includes the post-treatment catalyst 10 and the detection means 40 shown in FIGS. 1 and 2.
The aftertreatment catalyst 10 is disposed at the rearmost part of the exhaust passage 12 of the diesel engine 1. The post-treatment catalyst 10 is composed of, for example, a particulate filter (DPF) that removes particulate matter (PM) in exhaust gas.
The post-treatment catalyst 10 includes an oxidation catalyst that promotes an oxidation reaction of fuel and raises an exhaust gas temperature, and a continuously regenerative particulate filter (DPF) installed downstream of the oxidation catalyst. You can also.

  The post-treatment catalyst 10 can also be composed of an oxidation catalyst that promotes an oxidation reaction of the fuel and raises the exhaust gas temperature, and a selective reduction NOx catalyst that is installed downstream of the oxidation catalyst. The selective reduction NOx catalyst (SCR) reduces nitrogen oxides (NOx) to nitrogen. For example, urea is supplied from the outside to change to ammonia, and this ammonia reacts with NOx in the exhaust gas. Thus, a urea SCR device that converts NOx to nitrogen is known.

  The detection means 40 detects the exhaust pressure, exhaust temperature, etc., upstream and downstream of the post-treatment catalyst 10. As shown in FIG. 1, the detection means 40 is specifically a pressure sensor 40a disposed on the inlet side of the post-treatment catalyst 10, a temperature sensor 40b for detecting the exhaust gas temperature in the vicinity of the post-treatment catalyst 10, and an engine rotation. The engine rotation sensor 40d that detects the number, the rack position sensor 40e that detects the fuel injection amount, and the like are connected to the controller 41 as shown in FIG.

As shown in FIG. 2, the controller 41 is connected to the detection means 40, the notification means 50, the switching valve 20, the rack actuator 52, and the like. The controller 41 mainly includes a storage unit 42, a calculation unit 43, and the like. The storage unit 42 includes a ROM that stores various control programs and a RAM that is used as a work area for data storage and program execution.
The controller 41 calculates the load of the diesel engine 1 from the pressure in the vicinity of the post-treatment catalyst 10 detected by the detection means 40 and determines whether or not to perform rotation control of the supercharger 2 by the hydraulic turbine 16.

  The rack actuator 52 is constituted by a solenoid or the like, and discharges the fuel injection amount calculated by the controller 41 from the fuel injection pump and sends it to the fuel injection nozzle. In the case of the common rail type fuel injection device, the rack position sensor 40e is not provided, a sensor for detecting the pressure of the common rail is provided, and an electromagnetic valve type fuel injection valve is provided in each cylinder instead of the rack actuator 52. By changing the timing of fuel injection into the cylinder, the rotational speed, torque, etc. can be changed, and the exhaust temperature can be changed and unburned fuel can be supplied to the exhaust gas.

The intake throttle valve 53 includes a valve body that is opened and closed by an electromagnetic valve or an actuator. The intake throttle valve 53 is disposed in the intake passage 11 of the diesel engine 1 and adjusts the air inflow amount of the diesel engine 1. By changing the opening of the intake throttle valve 53, it is possible to change the exhaust gas flow rate, the exhaust temperature, and the exhaust speed.
The notification means 50 is a means for notifying whether or not the post-processing catalyst 10 is operating normally. For example, when the post-processing catalyst 10 is not operating normally, an alarm device such as a lamp or a buzzer is activated. To do.

Next, rotation control of the supercharger 2 will be described.
The supercharger 2 supercharges the intake side in order to ensure sufficient air. However, when the load of the diesel engine 1 is low, excessive air due to supercharging suppresses an increase in gas temperature, and further, the exhaust temperature decreases due to expansion by the supercharger 2, and the post-treatment catalyst 10 does not work sufficiently. There was a thing. That is, when the post-treatment catalyst 10 is composed of a particulate filter, the recyclable temperature of the particulate filter is about 300 ° C. or higher. When the post-treatment catalyst 10 is composed of an oxidation catalyst and a continuous regeneration type particulate filter (DPF) installed downstream of the oxidation catalyst, the activation temperature of the oxidation catalyst is about 300 ° C. or higher. Further, when the oxidation catalyst and the selective reduction NOx catalyst installed downstream of the oxidation catalyst are used, the active temperature of the selective reduction NOx catalyst (SCR) is about 350 ° C. or higher. For this reason, the post-treatment catalyst 10 does not work sufficiently unless the temperature is at least about 300 ° C. or higher. Therefore, when the load on the diesel engine 1 is low, rotation control of the supercharger 2 is performed.
The explanatory diagram shown in FIG. 3 is a diagram of a load pattern representing the relationship between the engine speed and the engine load when the diesel engine 1 is driven, and is stored in the storage unit 42. In FIG. 3, the engine rotational speed is taken on the horizontal axis, and the engine load correlated with the rack position is taken on the vertical axis.

  The load pattern LP of the present embodiment is a region surrounded by a maximum torque line ML that is an upwardly convex line, and represents the relationship between the engine speed R and the engine load L when the exhaust gas temperature is a renewable temperature. Divided vertically at the boundary line BL. The upper region across the boundary line BL is a region where the post-treatment catalyst 10 normally operates, and the lower region is a region where the post-treatment catalyst 10 is difficult to work and exhaust purification cannot be performed.

  When the post-treatment catalyst 10 is in a region where the post-treatment catalyst 10 normally operates, as shown in FIG. 4, the lubricating oil is supplied in the rotational direction of the turbine shaft 14 supercharged by the supercharger 2 from the oil passage 18C through the lubricating oil inlet 17A. The switching valve 20 is switched so as to flow. With this configuration, when the exhaust gas purification device 3 works normally, the supercharger 2 works normally and compresses the intake air.

  Further, when the post-processing catalyst 10 is in a region where it is difficult to work and exhaust purification cannot be performed, as shown in FIG. 4, it is opposite to the rotation in which the supercharger 2 is supercharged from the oil passage 18C through the lubricating oil inlet 17B. The switching valve 20 is switched so that the lubricating oil flows so as to rotate in the direction. With this configuration, the rotation of the supercharger 2 is suppressed when the exhaust gas purification device 3 is not working. That is, a force acts in the direction in which the rotation of the lubricating oil strikes the rotating blades 16a of the hydraulic turbine 16 in the direction opposite to the rotating direction in which the turbine shaft 14 is rotated by the rotation of the turbine unit 13 rotated by the exhaust. . Thereby, supply of excess air can be prevented, and expansion of exhaust gas can be prevented, and a decrease in exhaust temperature can be prevented. Further, during normal times, more air can be supplied by promoting the rotation of the supercharger 2.

Further, the rotation control of the supercharger 2 according to another embodiment will be described with reference to FIG.
An on-off valve 70 is provided in the middle of the lubricating oil passage 18 to control whether the lubricating oil flows through the lubricating oil passage 18 or not. Further, the lubricating oil chamber 17 is provided with a single lubricating oil inlet 17B and connected to the lubricating oil passage 18. Between the lubricating oil inlet 17B and the lubricating oil outlet 17C, the lubricating oil passes through the supercharger 2. It is configured to flow in the direction opposite to the feeding direction. The on-off valve 70 is connected to the controller 41. Since the configuration of the diesel engine 1 other than the on-off valve 70 and the lubricating oil inlet 17B is the same as that of the first embodiment, the description thereof is omitted.

  In this way, when the post-treatment catalyst 10 is in a region where the post-treatment catalyst 10 normally operates, the supercharger 2 is configured by switching the on-off valve 70 to the closed state so as not to add resistance to the rotary blades 16a of the hydraulic turbine 16. Works normally and compresses inspiration.

  Further, when the post-treatment catalyst 10 is in a region where it is difficult to work and exhaust purification cannot be performed, the on-off valve 70 is switched to the open state. By configuring in this way, the exhaust gas purification device 3 is in a state in which it does not work. Therefore, the rotation of the supercharger 2 is suppressed by flowing lubricating oil and applying resistance to the rotating blades 16a of the hydraulic turbine 16. That is, the lubricating oil flows in a direction opposite to the rotating direction of the turbine shaft 14 of the turbine section 13, the lubricating oil hits the rotating blades 16 a of the hydraulic turbine 16, and the force in the direction of suppressing the rotation acts. The rotation of the shaft 14 and the compressor unit 15 can be suppressed. Thereby, supply of excess air can be prevented, and expansion of exhaust gas can be prevented, and a decrease in exhaust temperature can be prevented.

Further, rotation control according to another embodiment will be described with reference to FIG.
Two on-off valves 80 and 80 for opening and closing the lubricating oil passage 18 are provided in the middle of the lubricating oil passage 18. The lubricating oil chamber 17 is provided with two lubricating oil inlets 17A and 17B, and the lubricating oil flowing in from one lubricating oil inlet 17A flows in the direction in which the turbine shaft 14 rotates when the turbocharger 2 operates. It is configured as follows. Further, the lubricating oil flowing in from the other lubricating oil inlet 17B is configured to flow in a direction opposite to the direction in which the turbine shaft 14 rotates when the supercharger 2 operates. The on-off valves 80 and 80 are connected to the controller 41. Since the configuration of the diesel engine 1 other than the on-off valves 80 and 80 and the lubricating oil inlets 17A and 17B is the same as that of the first embodiment, the description thereof is omitted.

  When the post-treatment catalyst 10 is in a normal working region, the on-off valve is configured to supply the lubricating oil to the lubricating oil inlet 17A through which the lubricating oil can flow in the direction in which the turbine shaft 14 rotates when the supercharger 2 operates. Switch 80 to the open state. With this configuration, when the exhaust gas purification device 3 works normally, the supercharger 2 works normally and compresses the intake air.

  Further, when the post-treatment catalyst 10 is in a region where it is difficult to work and exhaust purification cannot be performed, a lubricating oil inlet that allows the lubricating oil to flow in a direction opposite to the direction in which the turbine shaft 14 rotates when the supercharger 2 operates. The on-off valve 80 is switched to an open state so as to supply lubricating oil to 17B. With this configuration, the rotation of the supercharger 2 is suppressed when the exhaust gas purification device 3 is not working. That is, when the lubricating oil flows in a direction opposite to the rotating direction of the turbine shaft 14 and the hydraulic turbine 16 linked to the rotation of the turbine unit 13, the lubricating oil hits the rotating blades 16 a of the hydraulic turbine 16 and suppresses the rotation. Since the directional force acts, rotation of the turbine shaft 14 and the compressor unit 15 can be suppressed. Thereby, supply of excess air can be prevented, and expansion of exhaust gas can be prevented, and a decrease in exhaust temperature can be prevented. Further, during normal times, more air can be supplied by promoting the rotation of the supercharger 2.

Further, rotation suppression control according to another embodiment will be described with reference to FIG.
An opening adjusting valve 90 for adjusting the opening of the lubricating oil passage 18 is provided in the middle of the lubricating oil passage 18. The lubricating oil chamber 17 is provided with a lubricating oil inlet 17B so that the lubricating oil flowing in from the lubricating oil inlet 17B flows in a direction opposite to the direction in which the turbine shaft 14 rotates when the turbocharger 2 operates. is doing. The opening control valve 90 is connected to the controller 41. Since the configuration of the diesel engine 1 other than the opening control valve 90 and the lubricating oil inlet 17A is the same as that of the first embodiment, the description thereof is omitted.

  When the post-treatment catalyst 10 is in a normal working region, the valve body 90a of the opening degree adjusting valve 90 is slid in the closing direction so as to block the lubricating oil. With this configuration, when the exhaust gas purification device 3 works normally, the supercharger 2 works normally and compresses the intake air.

  When the post-treatment catalyst 10 is in a region where it is difficult to work and exhaust purification cannot be performed, the valve element 90a of the opening degree adjustment valve 90 is slid in the opening direction so as to supply lubricating oil. Here, the opening degree control of the opening degree adjusting valve 90 is to set an opening degree corresponding to the map in advance and adjust the opening degree corresponding to the position of the map. With this configuration, when the exhaust gas purification device 3 is not working, the rotation of the supercharger 2 is suppressed corresponding to the engine load and the engine speed. That is, when the lubricating oil flows in a direction opposite to the rotating direction of the turbine shaft 14 and the hydraulic turbine 16 linked to the rotation of the turbine unit 13, the lubricating oil hits the rotating blades 16 a of the hydraulic turbine 16 and suppresses the rotation. Since the directional force acts, rotation of the turbine shaft 14 and the compressor unit 15 can be suppressed. Thereby, supply of excess air can be prevented, and expansion of exhaust gas can be prevented, and a decrease in exhaust temperature can be prevented. Further, by controlling the opening degree of the opening degree adjusting valve 90, it is possible to set the flow rate of the lubricating oil suitable for the engine load state.

  Further, as shown in FIG. 1, the exhaust passage 12 is provided with a waste gate 100 for sending exhaust to the post-treatment catalyst 10 without passing through the turbine section 13. The waste gate 100 is provided with an inlet 100 a on the diesel engine 1 side from the turbine portion 13 of the exhaust passage 12, and an outlet 100 b is provided on the aftertreatment catalyst 10 side with respect to the turbine portion 13 of the exhaust passage 12. Further, a control valve 101 is provided in the middle of the waste gate 100, and all the exhaust gas passes through the turbine section 13 by closing the control valve 101 in a normal state.

  The control valve 101 is controlled so as to be in an open state when it is in a region where the post-treatment catalyst 10 is hard to work and exhaust purification cannot be performed. By comprising in this way, the exhaust_gas | exhaustion amount which flows in into the turbine part 13 can be decreased, and rotation of the supercharger 2 can be suppressed. Thereby, supply of excess air can be prevented, and expansion of exhaust gas can be prevented, and a decrease in exhaust temperature can be prevented.

As described above, in the diesel engine 1 including the exhaust purification device 3 connected to the exhaust passage 12 and the supercharger 2 that compresses the intake air in the intake passage 11, the supercharger 2 is connected to the exhaust passage 12. A turbine section 13 provided, a compressor section 15 for supplying and compressing air provided in the intake passage 11, and a turbine shaft 14 connecting the turbine section 13 and the compressor section 15. 16 is provided in a lubricating oil passage 18 for supplying lubricating oil to the hydraulic turbine 16, and when the engine load is low, the direction in which the hydraulic turbine 16 rotates to suppress the rotation of the turbine shaft 14 When the engine load is normal, the lubricating oil is supplied in the same direction as the direction in which the hydraulic turbine 16 rotates in order to promote the rotation of the turbine shaft 14. It is obtained by controlling the switching valve 20 to supply.
With this configuration, when the load is low, the rotation of the supercharger 2 is suppressed to prevent excessive supply of air, and the amount of exhaust flowing into the turbine unit 13 is limited, thereby reducing the amount of exhaust. Expansion can be prevented and exhaust temperature drop can be prevented. Further, during normal times, more air can be supplied by promoting the rotation of the supercharger 2.

In the diesel engine 1 including the exhaust purification device 3 connected to the exhaust passage 12 and the supercharger 2 that compresses the intake air in the intake passage 11, the supercharger 2 is a turbine provided in the exhaust passage 12. Part 13, a compressor part 15 for supplying and compressing air provided in the intake passage 11, and a turbine shaft 14 that connects the turbine part 13 and the compressor part 15, and a hydraulic turbine 16 is connected to the turbine shaft 14. An on-off valve 70 is provided in the lubricating oil passage 18 for supplying the lubricating oil to the hydraulic turbine 16, and when the engine load is low, the direction opposite to the direction in which the hydraulic turbine 16 rotates in order to suppress the rotation of the turbine shaft 14. The on-off valve 70 is controlled so as to supply lubricating oil.
With this configuration, when the load is low, the rotation of the supercharger 2 is suppressed to prevent excessive supply of air, and the amount of exhaust flowing into the turbine unit 13 is limited, thereby reducing the amount of exhaust. Expansion can be prevented and exhaust temperature drop can be prevented. Moreover, since it controls by the comparatively cheap on-off valve 70, cost can be suppressed.

In the diesel engine 1 including the exhaust gas purification device 3 connected to the exhaust passage 12 and the supercharger 2 that compresses the intake air in the intake passage 11, the supercharger 2 is a turbine provided in the exhaust passage 12. Part 13, a compressor part 15 for supplying and compressing air provided in the intake passage 11, and a turbine shaft 14 that connects the turbine part 13 and the compressor part 15, and a hydraulic turbine 16 is connected to the turbine shaft 14. Two on-off valves 80, 80 are provided in the lubricating oil passage 18 for supplying the lubricating oil to the hydraulic turbine 16, and the hydraulic turbine 16 rotates to suppress the rotation of the turbine shaft 14 when the engine load is low. When lubricating oil is supplied in the direction opposite to the direction and the engine load is normal, the oil is lubricated in the same direction as the direction in which the hydraulic turbine 16 rotates to promote the rotation of the turbine shaft 14. Oil is obtained by controlling the two closing valves 80, 80 to supply.
With this configuration, when the load is low, the rotation of the supercharger 2 is suppressed to prevent excessive supply of air, and the amount of exhaust flowing into the turbine unit 13 is limited, thereby reducing the amount of exhaust. Expansion can be prevented and exhaust temperature drop can be prevented. Further, since the control is performed by the relatively inexpensive on-off valves 80 and 80, the cost can be suppressed. Further, during normal times, more air can be supplied by promoting the rotation of the supercharger 2.

In the diesel engine 1 including the exhaust gas purification device 3 connected to the exhaust passage 12 and the supercharger 2 that compresses the intake air in the intake passage 11, the supercharger 2 is a turbine provided in the exhaust passage 12. Part 13, a compressor part 15 for supplying and compressing air provided in the intake passage 11, and a turbine shaft 14 that connects the turbine part 13 and the compressor part 15, and a hydraulic turbine 16 is connected to the turbine shaft 14. The opening adjusting valve 90 is provided in the lubricating oil passage 18 that supplies the lubricating oil to the hydraulic turbine 16, and when the engine load is low, the rotation direction of the hydraulic turbine 16 is controlled so as to suppress the rotation of the turbine shaft 14. In order to supply lubricating oil in the reverse direction, the opening degree of the opening degree adjusting valve 90 is controlled.
With this configuration, when the load is low, the rotation of the supercharger 2 is suppressed to prevent excessive supply of air, and the amount of exhaust flowing into the turbine unit 13 is limited, thereby reducing the amount of exhaust. Expansion can be prevented and exhaust temperature drop can be prevented. Further, by controlling the opening degree of the opening degree adjusting valve 90, it is possible to set the flow rate of the lubricating oil suitable for the load state.

  Further, a waste gate 100 is provided in the exhaust passage 12, and the waste gate 100 is provided with an inlet 100 a on the diesel engine 1 side from the turbine portion 13 of the exhaust passage 12, and an aftertreatment catalyst is provided from the turbine portion 13 of the exhaust passage 12. The outlet 100b is provided on the 10 side. With this configuration, by opening the wastegate 100, it is possible to prevent the exhaust from expanding and to prevent the exhaust temperature from decreasing.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which showed the whole structure of the diesel engine which concerns on one Example of this invention. The block diagram which shows the control system of a controller. Explanatory drawing which shows the relationship between an engine load and an engine speed. Sectional drawing which shows a lubricating oil chamber. Sectional drawing which shows a lubricating oil chamber. Sectional drawing which shows a lubricating oil chamber. Sectional drawing which shows a lubricating oil chamber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Supercharger 3 Exhaust purification device 10 Post-processing catalyst 11 Intake passage 12 Exhaust passage 13 Turbine part 14 Turbine shaft 15 Compressor part 16 Hydraulic turbine 18 Lubricating oil path 20 Switching valve 70 Open / close valve 80 Open / close valve 90 Opening adjustment Valve 100 Westgate 100a Inlet 100b Outlet

Claims (5)

In a diesel engine comprising an exhaust purification device connected to an exhaust passage, and a supercharger that compresses intake air in the intake passage,
The supercharger is composed of a turbine part provided in an exhaust passage, a compressor part for air supply compression provided in an intake passage, and a turbine shaft connecting the turbine part and the compressor part,
A hydraulic turbine is pivotally supported on the turbine shaft, a switching valve is provided in an oil passage for supplying lubricating oil to the hydraulic turbine, and when the engine load is low, the direction of rotation of the hydraulic turbine to suppress the rotation of the turbine shaft The switching valve is controlled so that the lubricating oil is supplied in the opposite direction, and when the engine load is normal, the lubricating oil is supplied in the same direction as the rotating direction of the hydraulic turbine in order to promote the rotation of the turbine shaft. Diesel engine. In a diesel engine comprising an exhaust purification device connected to an exhaust passage, and a supercharger that compresses intake air in the intake passage,
The supercharger is composed of a turbine part provided in an exhaust passage, a compressor part for air supply compression provided in an intake passage, and a turbine shaft connecting the turbine part and the compressor part,
A hydraulic turbine is pivotally supported on the turbine shaft, and an on-off valve is provided in an oil passage for supplying lubricating oil to the hydraulic turbine. When the engine load is low, the direction of rotation of the hydraulic turbine in order to suppress rotation of the turbine shaft; A diesel engine characterized in that the on-off valve is controlled to supply lubricating oil in the reverse direction. In a diesel engine comprising an exhaust purification device connected to an exhaust passage, and a supercharger that compresses intake air in the intake passage,
The supercharger is composed of a turbine part provided in an exhaust passage, a compressor part for air supply compression provided in an intake passage, and a turbine shaft connecting the turbine part and the compressor part,
A hydraulic turbine is supported on the turbine shaft, and two on-off valves are provided in an oil passage for supplying lubricating oil to the hydraulic turbine. When the engine load is low, the hydraulic turbine rotates to suppress the rotation of the turbine shaft. Control the two on-off valves to supply the lubricating oil in the same direction as the direction of rotation of the hydraulic turbine in order to promote the rotation of the turbine shaft when the engine load is normal and the lubricating oil is supplied in the opposite direction. Diesel engine characterized by In a diesel engine comprising an exhaust purification device connected to an exhaust passage, and a supercharger that compresses intake air in the intake passage,
The supercharger is composed of a turbine part provided in an exhaust passage, a compressor part for air supply compression provided in an intake passage, and a turbine shaft connecting the turbine part and the compressor part,
A hydraulic turbine is pivotally supported on the turbine shaft, and an opening degree adjusting valve is provided in an oil passage for supplying lubricating oil to the hydraulic turbine. When the engine load is low, the hydraulic turbine rotates to suppress the rotation of the turbine shaft. A diesel engine characterized in that the opening of the opening adjustment valve is controlled in order to supply lubricating oil in the direction opposite to the direction. A waste gate is provided in the exhaust passage, the waste gate is provided with an inlet on the engine side from the turbine portion of the exhaust passage, and an outlet is provided on the aftertreatment catalyst side from the turbine portion of the exhaust passage. The diesel engine according to any one of claims 1 to 4.

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