JPH065028B2 - Turbo Compound Engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a turbo compound engine that recovers energy of exhaust gas as expansion work of a turbine and uses the recovered energy as rotational energy of a drive shaft such as a crankshaft. In particular, the present invention relates to a turbo compound engine configured to optimally apply engine braking force according to the operating state of the engine.

[Prior Art] Generally, an engine provided with a supercharger has better fuel efficiency than a non-supercharged engine having a larger displacement than this engine, an output performance equal to or higher than that of a non-supercharged engine, an engine is lightweight and compact, etc. Has the excellent advantages of A turbo compound engine is one of the advantages of this product. This turbo compound engine first collects the exhaust gas energy from the engine as supercharging work of the turbocharger and then recovers the exhaust gas discharged from the turbocharger as adiabatic expansion work of the power turbine. It was done. As a result, the engine output performance, fuel efficiency performance, and gain can be comprehensively improved. By the way, in order to further improve the overall performance of the turbo compound engine, the expansion ratio of the turbocharger and the expansion ratio of the tower turbine are increased to further increase the supercharging pressure,
The usefulness can be increased, however, securing the engine braking force (exhaust braking force) corresponding to the increase in output performance remains a problem.

That is, by increasing the supercharging pressure value, the relative engine braking force becomes smaller, and the main brake (foot brake) operation is required by this amount. Ensuring the engine braking force is an essential element for safe driving of the vehicle as well as the operability of the vehicle (engine braking force requires 60% or more of the rated output.), And to take advantage of the turbo compound engine Will also be an important issue.

Therefore, the applicant of the present invention had previously proposed a "turbo compound engine" (Japanese Patent Application No. 61-308776).

In this proposal, as shown in FIG. 6, a power turbine a and a crank shaft b are connected by a gear train d that has an electromagnetic clutch c that connects the power turbine a and the crank shaft b when the exhaust brake is activated, and that transmits the rotation of the crank shaft to the power turbine a. At the same time, the gear ratio of the gear train d is set to be smaller than the gear ratio of the gear train e that transmits the rotational force of the power turbine to the crankshaft b when the exhaust brake is not operated, thereby forming a turbo compound engine.

[Problems to be Solved by the Invention] Generally, the operation of the exhaust brake may be performed even when the engine exceeds the rated rotation,
At this time, there is a high possibility that the power turbine will overrun.

Therefore, in the above proposal, when the exhaust brake is operated, the electromagnetic train is connected to operate the gear train that transmits the rotation of the crankshaft to the power turbine, and drives the power turbine in the reverse direction. At this time, the gear ratio of the gear train that transmits rotation from the power turbine to the crankshaft when the exhaust brake is not operating is smaller than the gear ratio of the gear train that transmits rotation from the crankshaft to the power turbine. The run is prevented.

By the way, with the configuration of the above proposal, the energy absorption force as a brake can secure 1/3 or more of the engine output, but on the other hand, if all of the absorbed braking force acts at the same time during running, Various problems occur such as the tires skid temporarily and slipping of the tires, the anti-driving force at skid is applied as a maximum load to the drive system of the vehicle, or abnormal wear of the tires occurs. It is a problem to be solved.

[Means for Solving the Problems] The present invention relates to a gear train that connects a crankshaft of an engine and a power turbine, and is configured to rotate the power turbine in a reverse direction, and switches the gear train between ON and OFF. A clutch, a movable nozzle vane that adjusts the nozzle throat area of the power turbine, an actuator that operates this movable nozzle vane, a map of the nozzle throat area during vehicle braking based on the gross vehicle weight, a nozzle throat area during vehicle braking based on the vehicle speed. , A map of the nozzle throat area during vehicle braking based on the engine speed, and a map of the nozzle throat area based on the elapsed time during vehicle braking, the nozzle throat area is first activated by operating the actuator during vehicle braking. And set the maximum to After turning on the switch, the actual vehicle speed, total vehicle weight, engine speed, and elapsed time are checked against each of the above maps to find the optimum nozzle throat area for each map. A controller is provided which selects the optimum nozzle throat area having the largest area from among the areas and repeats the control for operating the actuator so that the selected optimum nozzle throat area becomes the selected optimum nozzle throat area.

[Operation] During vehicle braking, the controller first actuates the actuator to set the nozzle throat area to the maximum and also turns on the clutch. After this, the controller
The actual vehicle speed, total vehicle weight, engine speed, and elapsed time are checked against each of the above maps to find the optimum nozzle throat area for each map, and the optimum nozzle throat area with the largest area out of these optimum nozzle throat areas Is selected, and the control for operating the actuator is repeated so that the selected optimum nozzle throat area is achieved.

[Embodiment] A preferred embodiment of a turbo compound engine of the present invention will be described below with reference to the accompanying drawings.

In FIG. 2, 1 is an engine, 2 is an intake manifold, and 3 is an exhaust manifold.

As shown, the exhaust manifold 3 has an exhaust passage 4a.
Is connected, and an intake passage 5 is connected to the intake manifold 2.

In the exhaust passage 4a, a turbine 10a of a turbocharger 10 is provided in the middle of the exhaust passage 4a.
The compressor 10b is installed in the middle of the intake passage 5.
A power turbine 12 for recovering exhaust gas energy is provided in the exhaust passage 4b on the downstream side of the turbocharger 10.

By the way, the turbo compound engine of this invention is
It is to secure the engine braking force according to the output performance of the engine 1. In order to increase the engine braking force, it is considered effective to add resistance to the crankshaft 15 that directly or indirectly blocks rotation so that the crankshaft 15 performs a large negative work.

For this reason, in the turbo compound engine of the present invention, the power turbine 12 is reversed when the exhaust brake is actuated, and the power turbine 12 is made to perform a large negative work.

As shown in Fig. 2, the power turbine 12 and the turbocharger
The exhaust passage 4b between the turbine 10 and the turbine 10a is formed with a fluid passage 25 having one end connected to the exhaust passage 4b and the other end connected to the exhaust passage 4c downstream of the power turbine 12. A flow path switching means 30 is provided at a connection portion upstream of the power turbine 12.

In this embodiment, the flow path switching means 30 is a rotary valve 31 as a switching valve provided at the above-mentioned connecting portion as shown in FIGS. 2 to 4, and a drive device 32 for operating this rotary valve 31. Composed of and. Rotary valve
31 is a casing 31a as shown in FIGS. 3 and 4.
A rotatable rotor 31b is housed in this rotor 31b, and
It is configured by forming a first port A and a second port B. On the other hand, the port diameter d ₁ of the first port A is equal to the exhaust passage 4
The port diameter d ₂ of the second port B is equal to the passage diameter d ₀ of d, and is smaller than the passage diameter d ₃ of the fluid passage 25.

On the other hand, the casing 31a is formed with a through hole 31c which is a part of the exhaust passage 4b. The rotational position relationship between the first port A and the second port B is set such that the exhaust passage 4b and the fluid passage 25 are disconnected when the exhaust passage 4b and the first port A are connected. .

The drive device 32 that switches and controls the rotary valve 31 is configured as follows.

As shown in FIGS. 2 and 3, a lever member 35, one end of which is fixed to the rotor 31b, is connected to the rotor 31b, and the lever member 35 extends outward in the radial direction of the exhaust passage 4b. The working rod 33 of the actuator 34 is connected to the free end of the.

Reference numeral 36 shown in FIG. 2 denotes a fluid supply device.
36 and the working chamber 37 of the actuator 34 are connected by a fluid supply passage 39, and the working chamber 37 and the fluid supply passage 39 are connected to each other when electricity is supplied to the middle of the fluid supply passage 39. A solenoid valve 40 for setting the state is provided. The solenoid valve 40 is adapted to be energized when all of the neutral sensor switch 41, the clutch operation switch 42, and the exhaust brake switch 43 of the engine 1 are turned on. 45
Is a DC power source such as a battery.

47 is an electromagnetic clutch switch for reverse rotation, which is a normally open contact (A contact).

Next, the gear train that connects the power turbine 12 and the crankshaft 15 will be described.

As shown in FIG. 1, an output gear 16 is integrally provided at an output end 13a of a turbine shaft 13 of a power turbine 12, and planet gears 17a and 17b are meshed with the output gear 16. . The planetary gears 17a and 17b are meshed with an annular gear 18 that rotates integrally with the input pump wheel 21a of the fluid coupling 21.

That is, the output gear 16 is connected to the fluid coupling 21 by the planetary gear mechanism 19 composed of the planetary gears 17a, 17b and the annular gear 18, so that the rotational force from the power turbine 12 is transmitted to the output pump wheel 21b of the fluid coupling 21. It is configured. The planetary gear mechanism 19 is provided here because the planetary gear mechanism 19 has a large reduction gear ratio and good transmission efficiency. An input / output gear 20 is fixed to the output pump car 21b and rotates integrally with the output pump car 21b.

By the way, the crankshaft 15 has a built-in electromagnetic clutch 22, and the electromagnetic clutch 22 intermittently rotates the first clutch.
A crankshaft gear 23 and a second crankshaft gear 24 are integrally provided, and the second crankshaft gear 24 is meshed with a second intermediate gear 27 having a one-way clutch 26 built therein. Second
The intermediate gear 27 is connected to the input / output gear 20 via a first intermediate gear 28 that is coaxially connected.

The first intermediate gear 28 and the first crankshaft gear 23 are connected by a reverse rotation idle gear 29, and when the electromagnetic clutch 22 is "on", that is, the electromagnetic clutch switch 47 is ON, First crankshaft gear 23 and first intermediate gear 28
Are connected, and the rotational driving force from the crankshaft 15 is transmitted to the input / output gear 20. At this time the second
By providing the one-way clutch 26 between the intermediate gear 27 and the second crankshaft gear 24, the rotational force is not transmitted, and only the one-way clutch 26 is freely rotated.

By the way, with respect to the gear ratio between the input / output gear 20 and the second crankshaft gear 24, the first crankshaft gear 23 and the input / output gear 20
The gear ratio of each gear (the first crankshaft gear 23, the idle gear 29, the first intermediate gear 28, the input / output gear 20) is determined so as to reduce the gear ratio between the gears. This is to prevent overrun of the power turbine 12 when the driving force from the crankshaft 15 is transmitted to the power turbine 12 at the rated engine speed, and in the embodiment, the first crankshaft gear 23 and the first crankshaft gear 23 are used. 1 Gear ratio with the intermediate gear 28 is the second crankshaft gear
It is configured to be smaller than the gear ratio between 24 and the second intermediate gear 27.

Here, the second crankshaft gear 24, the one-way clutch 2
6, the first intermediate shaft gear 28, the input / output gear 20 is the power turbine 1
Gear train 56 that transmits rotation from 2 to crankshaft 15
The first crankshaft gear 23, the idle gear 29, the first intermediate gear 28, and the input / output gear 20 constitute a gear train 57 that transmits rotation from the crankshaft 15 to the power turbine 12.

In the embodiment of the present invention, as shown in FIG. 1, FIG. 3, and FIG. 4, the power turbine 12 has a housing 50 for housing the power turbine 12, and a nozzle throat of the power turbine 12. A movable nozzle vane for varying the area 51 to adjust the work of the power turbine 12 according to the flow velocity of the supplied fluid, and a driving means for adjusting the movable nozzle vane according to the operating state of the engine and the total weight of the vehicle body.
100 will be provided.

First, the structure of the movable nozzle vane will be described.

As shown in FIG. 1, the inner wall 50a of the housing 50 at a position radially outward of the power turbine 12 and a portion along the circumferential direction of the power turbine 12 have a predetermined interval between the power turbine 12 and the power turbine 12. A movable nozzle vane 52 for changing the nozzle throat area 51 is rotatably provided. In the embodiment, each movable nozzle vane 52 has a wing shape. Each movable nozzle vane 52 is rotatably supported by a rotary shaft 53 penetrating the housing 50 along the axial direction of the power turbine 12, and its blade angle can be arbitrarily changed.

Next, the driving means 100 will be described.

One end of the lever member 54 is integrally fixed to each of the end portions of the rotary shaft 53 that penetrates the housing 50,
The other ends of the lever members 54 are engaged with respective engaging portions 96 of the control ring 55 that is rotatably provided around the shaft center of the power turbine 12.

However, the control ring 55 and the movable nozzle vane 52 are set so that when the control ring 55 is rotated, the nozzle throat area 51 (hereinafter referred to as the throttle amount) formed by the power turbine 12 and each movable nozzle vane 52 is the same. It is natural to be done.

By the way, the control ring 55 is provided so as to be prevented from moving in the axial direction with respect to the housing 50, and the other end of the lever member 54 is also provided to the control ring 55 so as to be also prevented from moving in the axial direction.

One end serving as an action point of a control lever 57 that operates the control ring 55 via a lever member 54 is fixed to any one of the rotating shafts 53. When the control lever 54 is rotated, the control ring is rotated. 55 is rotated and each movable nozzle vane 52 is interlocked.

By the way, the control lever 97 is attached with a step motor 40 which drives the control lever 97 by a controller 62 described later, and the operating portion of the step motor 60 and the control lever 97 are connected by a link 61. There is.

However, the means for driving the control lever 97 is not limited to the step motor 40, and any means capable of adjusting the stroke of the link 61 by the controller 62 may be used.

Hereinafter, the configuration and control content of the controller 62 will be described.

As shown in FIG. 1, the controller 62 is configured such that a vehicle speed, an engine speed, a load amount, and an elapsed time are input to its input section. Elapsed time is step motor
Reference numeral 60 denotes a time from immediately after the movable nozzle vane 54 is once driven to an appropriate aperture amount and inputs it to the controller 62 as a signal. In addition to these signals, the input portion of the controller 62 is provided with an ON-OF switch for the exhaust brake switch 43.
F signal, ON-OFF signal of electromagnetic clutch operation switch 42, ON-OFF signal of accelerator switch (not shown)
Then, an ON-OFF signal of the solenoid valve 40 is input. Further, the controller 60 has its output section connected to the control section of the step motor 60.

Now, as shown in FIG. 5, the controller 62 maps various characteristics previously obtained from experimental data into maps 63, 64, 65, 6
6, 67 are stored internally, and the controller 62 performs a comparison operation between the stored values of these maps 63 to 67 and the input value, and then controls the step motor 60 based on the obtained value. It has become. These maps 63, 64, 6
In Nos. 5 and 66, the change of the aperture amount with respect to each parameter represents the change of the nozzle throat area. Therefore, increasing the throttle amount in each map 63, 64, 65, 66 means decreasing the nozzle throat area, and decreasing the throttle amount means increasing the nozzle throat area.

The control contents of the controller 62 will be described with reference to FIG.

First, the normal operation will be described.

When the exhaust brake switch 43 is OFF in judgment 68, the controller 62 judges that the clutch operation switch 42 is OF in judgment 69.
At F, when the accelerator switch is OFF at decision 70, the normal operation control 71 is executed.

That is, as shown in FIGS. 2 and 3, when the exhaust brake switch 43 is OFF, the solenoid valve 40 is OFF, so the exhaust passage 4d immediately upstream of the power turbine 12 and the upstream of the rotary valve 31. The exhaust passage 4d on the side is connected via the first port A. The exhaust gas is sent from the engine 1 to the exhaust manifold 3 and the exhaust passage 4a, and the exhaust gas energy is recovered by the turbine 10a of the turbocharger 10. Since the turbine 10a rotationally drives the compressor 10b on the same axis, supercharged air is sent into the cylinder of the engine 1. The exhaust gas that has exited the turbine 10a of the turbocharger 10 gives a rotational driving force to the power turbine 12. That is, the exhaust gas energy is recovered again by the power turbine 12. At this time, since the electromagnetic clutch 22 is "disengaged", the exhaust gas energy recovered by the power turbine 12 is first decelerated by the planetary gear mechanism 19, and the rotation after deceleration is performed by the input / output gear 20 at the second intermediate position. It is transmitted to the gear 27 and the second crankshaft gear 24. As a result, the rotational force is transmitted to the crankshaft 15 and used as rotational energy.

Here, the opening of the movable nozzle vane 52 is set to the power turbine 12
It is also possible to adjust the exhaust gas energy in a range that does not cause overrun, and to effectively recover the exhaust gas energy. At this time, the control is performed by the controller 62 based on a map in which the operating state of the engine is stored.

Next, the operation of the exhaust brake will be described.

When the determinations 68, 69, 70 are all YES, the exhaust brake operation is controlled.

Neutral sensor switch 41 when the exhaust brake is activated,
This is when the clutch operation switch 42 and all of the accelerator switch and the exhaust brake switch 43 are ON. At this time, in step 72, the electromagnetic clutch switch 47 is turned on.
And turn on the solenoid valve 40. Then, the working fluid is supplied from the fluid supply device 36 to the operation chamber 37 of the actuator 34. That is, step 71a is executed and the operating rod 33 is
The rotary valve 31 is operated via the lever member 35, the exhaust passage 4b is closed, and the exhaust passage 4d downstream of the rotary valve 31 and the fluid passage 25 are communicated via the second port B. At the same time, the controller 62 turns the step motor 60
Is adjusted to the minimum (the nozzle throat area is maximum) in step 73. Next, at step 74, detection of the vehicle speed is executed.

Therefore, in the state where the rotational force due to the exhaust gas is not applied to the power turbine 12, conversely, the driving force of the crankshaft 15 is input via the first crankshaft gear 23, the idle gear 29, and the first intermediate gear 28. It is transmitted to the output gear 20 and the fluid coupling 21. That is, as shown in FIG. 4, the power turbine 12 becomes an inefficient compressor that is reversed to send air from the exhaust passage 4c downstream of the power turbine 12 to the connection portion of the fluid passage 25. In addition, the second port B allows the fluid passage
Since the gas sent to 25 is throttled, the flow velocity is increased. The air stirring work and the compressor work of the power turbine 12 become a large negative work for the crankshaft 15.
Therefore, when the exhaust brake is operated, the negative work, the negative work by the exhaust brake, and the friction of the engine are added appropriately, and an appropriate engine braking force that does not impose a load on the drive system of the vehicle is produced. The exhaust brake is composed of an exhaust brake valve (not shown) provided downstream of the exhaust manifold 3 and is operated by the operation of the exhaust brake. An increase in exhaust resistance, that is, an increase in pumping work due to the brake valve being fully closed becomes an engine braking force by the exhaust brake valve. However, the diameter of the second port B is uniquely determined by the shape of the power turbine 12, but is set to a port diameter d ₂ that does not overrun the power turbine 12 (see FIGS. 3 and 4). .). The controller 62 then performs vehicle speed detection in step 74. The vehicle speed detected in step 75 is compared with the stored value in the map 63. Therefore, the optimum throttle amount D ₀ for the vehicle speed is obtained. Next, in step 76, the loading amount of the vehicle is detected, in step 77, the optimum aperture amount DT for the detected load amount is obtained from the map 64, and in decision 78, the optimal aperture amounts D ₀ , DT are calculated. Determine which one has priority. That is, in the judgment 78, when DT <D _0, that is, when the optimal aperture amount for the loading amount is smaller than the optimal aperture amount for the vehicle speed, the optimal aperture amount DT at this time is set to the value of D ₀ . Judgment 78 is D
When T ≧ D ₀ , the optimum aperture amount is D ₀ and DT> D
Even when it is ₀ , the optimum aperture amount is D ₀ . That is, the aperture amount 51
Is controlled so that is always the minimum.

Next, the controller 62 detects the engine speed in step 79, and obtains the optimum throttle amount DE for the detected engine speed from the map 65 in step 80. After this,
At decision 81, it is decided which is given priority over D ₀ obtained immediately before. That is, when DE <D ₀ , DE is set to the value of D ₀ , and when DE ≧ D ₀ , D _{0 is set} to the optimum aperture amount.

Further, the controller 62 obtains the elapsed time from the actuation of the step motor 60 in step 82, and in step 83 the optimum aperture amount DM from the map 66 based on the elapsed time,
The elapsed time for maintaining the optimum aperture amount DM is obtained. After that, in decision 84, it is decided which of D ₀ and DM obtained immediately before is given priority. That is, when DM> D ₀ , DM is set to a value of D ₀ , and when DM ≧ D ₀ , D is set.
₀ is set as the value of judgment 84. The D ₀ obtained here becomes the final optimum aperture amount, and the operation amount of the step motor 60 with respect to D ₀ , that is, the operation angle of the step motor 60 (= step angle)
Is determined in step 85, and the step motor 60 is driven to the operating angle obtained in step 86.

Here, judgments 78, 81, 84 are vehicle speed, load capacity, engine speed,
The minimum optimum throttle amount D ₀ is obtained using the elapsed time as a parameter, and priority determination is performed so that a large exhaust brake force does not act on the drive system of the engine and the drive system of the vehicle at one time. . After this, if the vehicle is placed in a state where the exhaust braking force is further required, the presence or absence thereof is confirmed in decision 87, and if YES, the flow from step 74 to step 86 is repeated again, An exhaust braking force of an optimum magnitude is cyclically applied according to the driving state of the vehicle. Thus, during exhaust braking, a large driving force is not applied to the vehicle drive system, tire skids can be prevented, and shocks to the driver can be buffered.

By the way, in this embodiment, the connecting portion 4e of the exhaust passage 4c and the fluid passage 25 downstream of the power turbine 12 is
It is also possible to interpose a three-way valve 55 on the side of the exhaust passage 4c. With this configuration, the exhaust passage 4c is closed during the operation of the exhaust brake, and the purified atmosphere is compared with the exhaust gas. You will be able to incorporate directly.

In the embodiment of the present invention, the rotary valve 31 is used to switch the exhaust passage 4 and the fluid passage 25. However, the present invention is not limited to this. When the driving force in the direction is transmitted, an on-off valve that fully opens the exhaust passage 4b upstream of the connection portion of the fluid passage 25 and a valve that throttles the passage system of the fluid passage 25 to a predetermined opening are interlocked. You may allow it. Further, the fluid passage 25 may be formed in advance by narrowing it to a predetermined opening degree, and the exhaust passage 4b upstream of the fluid passage 25 may be opened and closed. Also. In adopting the rotary valve 31, the port diameter d ₂ of the port B is set to a port diameter that does not cause the power turbine 12 to overrun even when the movable nozzle vane 52 sets the nozzle throat area to the minimum. Is natural.

[Effects of the Invention] As is apparent from the above description, according to the present invention, an excellent effect that the vehicle can be braked with an appropriate braking force that does not cause skid on the tires is exhibited.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a preferred embodiment of a turbo compound engine of the present invention, FIG. 2 is a system diagram of a turbo compound engine according to the present invention, and FIGS. 3 and 4 are main part details of FIG. 5 and 5 are flowcharts showing the control contents of the controller, and FIG. 6 is a schematic diagram showing a conventional example. In the figure, 1 is an engine, 4 is an exhaust passage, 12 is a power turbine, 22 is an electromagnetic clutch, 25 is a fluid passage, 30 is a flow path switching means including a switching valve 31 and a drive device 32, and 56 is a crank from the power turbine. A gear train that transmits rotation to the shaft, 57 is a gear train that transmits rotation from the crankshaft to the power turbine, 52 is a movable nozzle vane, and 100 is drive means.

Claims (1)

[Claims] 1. A gear train connecting a crankshaft of an engine and a power turbine, the gear train configured to rotate the power turbine in a reverse direction, a clutch for switching the gear train between ON and OFF, and a nozzle of the power turbine. A movable nozzle vane that adjusts the throat area, an actuator that operates the movable nozzle vane, a map of the nozzle throat area during vehicle braking based on the gross vehicle weight, a map of the nozzle throat area during vehicle braking based on the vehicle speed, and the engine speed. A nozzle throat area map during vehicle braking based on the above and a nozzle throat area map based on the elapsed time during vehicle braking are provided, and the actuator is first operated to set the nozzle throat area to the maximum when the vehicle is braked. Turn on the clutch, after that, The optimum nozzle throat area is calculated for each map by collating the vehicle speed, the total vehicle weight, the engine speed, and the elapsed time with each of the above maps, and then the optimum nozzle throat area with the largest area is selected from these optimum nozzle throat areas. A turbo compound engine, comprising: a controller that selects a throat area and repeats control to operate the actuator so that the selected optimum nozzle throat area is obtained.