JPH0639902B2 - Engine braking system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine braking device having a power turbine that recovers energy of exhaust gas and returns it to a crankshaft of an engine.

[Prior Art] As a turbo compound engine having a power turbine in the exhaust system of the engine and configured to obtain a braking force by reversing the power turbine, the applicant's previous proposal (Japanese Patent Application No. 61-228107). No.)

In this proposal, a power turbine a for recovering exhaust gas energy is provided in an exhaust passage b ₁ as shown in FIG. 7, and a fluid passage bypassing the turbine a is provided in an exhaust passage b ₂ upstream of the turbine a. a flow path that connects c, closes the exhaust passage b ₂ upstream of the fluid passage c and opens the fluid passage c when the exhaust brake is actuated and when the driving force is transmitted from the crankshaft d to the turbine a. A switching means e is provided, and when exhaust braking is performed, the power turbine is driven by the driving force of the crankshaft, so that a resistance force due to the rotation of the power turbine is applied to the crankshaft to brake the engine.

[Problems to be Solved by the Invention] However, in an unloaded high rotation range where the exhaust brake and the engine brake are used together and the vehicle goes down a hill, the rotation speed of the power turbine may suddenly become excessive. There is a problem that braking by the turbine cannot be obtained.

[Means for Solving Problems] An object of the present invention is to solve the above problems. The present invention is connected to a crankshaft through a reversing mechanism and applies a driving force to the crankshaft at the time of normal rotation switching. When the power is transmitted, the power is recovered, and at the time of the reversal switching, the driving force is transmitted from the crankshaft and air is taken in and discharged while braking the crankshaft. It is equipped with a brake blower that takes in and discharges and brakes the crankshaft.

[Operation] The power turbine transfers the driving force to the crankshaft to recover the power when the reversing mechanism is switched to normal rotation.

Further, the power turbine is driven by the crankshaft at the time of reverse rotation switching, and takes in air while discharging it to brake the crankshaft.

The brake blower is connected to the crankshaft and driven by the crankshaft when the power turbine is excessively rotating, and takes in air while discharging it to brake the crankshaft.

Therefore, the engine is reliably braked.

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

1A shown in FIG. 1A is an engine, 2 is an intake port of the engine 1, and 3 is an exhaust port of the engine 1.

As shown, an intake passage 4 is connected to the intake port 2, and an exhaust passage 5 is connected to the exhaust port 3.

A turbine 6 of a turbocharger 6 is provided upstream 5a of the exhaust passage 5.
A is provided, and a power turbine 7 that recovers exhaust energy is provided in the exhaust passage 5a further downstream of the turbine 6a. The compressor 6b of the turbocharger 6 is provided upstream of the intake passage 4.

The exhaust passage 5 has one end connected to an exhaust passage 5a upstream of the power turbine 7 and the other end connected to an exhaust bypass passage 8 connected to an exhaust passage 5b downstream of the power turbine 7, and one end thereof connected to the intake passage 4 Of the intake bypass passage 9 whose other end is connected to the exhaust passage 5b downstream of the power turbine 7 and upstream of the connecting portion of the exhaust bypass passage 8
Tied with.

Downstream of the exhaust bypass passage 8, a throttle unit 10 that throttles the exhaust gas flow rate of the exhaust bypass passage 8 in order along the flow direction,
An on-off valve 11 for opening and closing the exhaust bypass passage 8 is provided,
An on-off valve 12 that opens and closes the intake bypass passage 9 is provided upstream of the intake bypass passage 9.

Further, the exhaust passage 5 upstream of the connecting portion of the exhaust bypass passage 8
On-off valves 13 and 14 for opening and closing the exhaust passages 5a and 5b are provided in a and 5b, respectively. These on-off valves 11,1
2, 13 and 14 are electromagnetic switching valves in the embodiment.

Now, the output shaft 15 of the power turbine 7 and the crankshaft 16 of the engine 1 return the rotational driving force of the power turbine 15 to the crankshaft 16 and, conversely, transmit the rotational driving force of the crankshaft 16 to the power turbine 7. It is connected by the reversing mechanism 17.

As shown, the turbine shaft 15 of the power turbine 7
An output gear 18 is fixed to the output end of the, and planet gears 19, 19 are meshed with the output gear 18.
These planetary gears 19 and 19 are meshed with an annular gear 22 that rotates integrally with an output pump wheel 21b of a fluid coupling 21 having a lockup mechanism 20. That is, the output gear 18 is connected to the fluid coupling 21 by the planetary gear mechanism 23 composed of the planetary gears 19 and 19 and the annular gear 22, so that the rotational driving force is transmitted from the power turbine 7 to the output pump wheel 21 a of the fluid coupling 21. Configured.

A first transmission gear 24, which rotates integrally with the output pump car 21a, is fixed to the output pump car 21a.

Next, a planetary gear mechanism 25 mainly constituting the reversing mechanism 17
Will be explained.

The planetary gear mechanism 25 is roughly classified into a sun gear shaft 27 having a sun gear 26 fixed to the shaft end of the output pump wheel 21a, and a plurality of sun gears 26 that are equally spaced in the circumferential direction of the sun gear 26 and are meshed with the sun gear. Of the planetary gears 28, an annular gear 29 having internal teeth meshing with the planetary gears 28, a carrier 30 of the planetary gears 28 that revolves around the sun gears 26 while rotating around the sun gears 26, The second transmission gear 31 meshed with the first transmission gear 24, and the second transmission gear 31
The one-way clutch 32 is provided coaxially with the second shaft to rotate the crankshaft gear 34 of the crankshaft 16 with the second rotation driving force.
A third transmission gear 33 for transmitting to the transmission gear 31, and a hydraulic clutch means 35 for freeing or fixing the carrier 30.
Composed of and.

In this embodiment, the hydraulic clutch means 35 is disengageable with a flange portion extending outwardly in the radial direction of the carrier 30, that is, a clutch portion 36, and a hydraulic clutch 37 for stopping the rotation of the carrier 30 at the time of connection. , A pump 38 for supplying hydraulic oil to the hydraulic clutch 37, and a pump 3
8 and an on-off valve 40 provided in a hydraulic oil passage 39 connecting the hydraulic clutch 37.

By the way, in the embodiment of the invention, as shown in FIG. 1B, a contact type or non-contact type sensor 41 for detecting the number of revolutions of the power turbine 7 by a pulse number is provided, and a detection signal from this sensor 41 is provided. On-off valve 1 based on
A controller 42 that performs opening / closing control of 1, 12, 13, and 14 is provided.

The configuration of the controller 42 will be described below.

The controller 42 has at its input part an ON-OFF signal of a clutch switch (not shown) of the engine 1, an ON-OFF signal of an accelerator switch (not shown), a rotation speed signal of the engine 1 by a sensor 59, a brake control switch signal. The rotation pulse signal of the sensor 41 is configured to be input, and the switching valves 11, 12, 1 are provided at the output section.
3, 14 and the on-off valve 40 of the reversing mechanism 17 are configured to output a control signal.

Next, the control content of the controller 42 will be described.

When the accelerator switch and the slatch switch are both OFF and the engine speed is, for example, 700 rpm or more, and it is determined in the determination 43 that the brake control switch is ON, the controller 42 determines that the braking is being performed, and the opening / closing valve 13,
After executing step 44 of outputting a closing signal to 14 and outputting an opening signal to the opening / closing valve 11, the opening / closing valve 40 is opened in step 45.
An open signal is output to the hydraulic pressure clutch 37 to connect the hydraulic clutch 37. Then, the reversing mechanism 17 transmits the rotational driving force of the crankshaft 16 to the power turbine 7, and the power turbine 7 is switched from normal rotation to reverse rotation.

Next, the controller 42 detects whether or not the power turbine 7 is rotating based on the detection signal from the sensor 41 at a judgment 46, and when the rotation of the power turbine 7 reaches “0”, a power is judged at 47. It is determined whether the difference N ₁ -N _{2 in the} number of rotation pulses per unit time of the turbine 7 is equal to or more than the set number N of pulses.

That is, in step 47, the power turbine 7 performs negative work due to reverse rotation, that is, air stirring work up to the rotational speed at which the power turbine 7 is reversed from 0 to effectively perform stirring work of exhaust gas consumed. It was made to let. Therefore, the set pulse number N is a test value given by the characteristics of various power turbines 7. If the pulse number difference becomes equal to or more than the set pulse number N in the judgment 47, the controller 42 outputs an open signal to the open / close valve 12 and executes step 48 to open the intake bypass passage 9. Air is introduced from the bypass passage 9, and the power turbine 7 performs a compressor work according to the amount of introduced air.

During normal operation, the controller 42 controls the open / close valve 13,
Control is performed so that 14 is open and the on-off valves 11, 12, 40 are closed. The throttle unit 10 is provided to make the pressure ratio before and after the turbine 7 appropriate.

An object of the present invention is to prevent over-rotation of the power turbine 7 and always brake the engine 1 with a stable braking force.

Therefore, the crankshaft 16 is provided with a brake blower 60 which is operated at the time of excessive rotation.

As shown in FIG. 1B, the brake blower 60 has a casing 61 that rotatably houses a blower 61 and a suction port 6 in the casing 61.
3 and the discharge port 64 are formed, penetrate through the casing 62, and are engaged with the transmission gear 66 fixed to the turbine shaft 7a of the power turbine 7 and the end of the blower shaft 65 axially supported by the casing 62. Transmission shaft 6 with gear 67
8 is connected by a fluid clutch 69 that transmits torque at a predetermined rotation speed.

Here, the predetermined rotation speed at which the brake blower 60 is turned on is the rotation speed N at which the power turbine 7 shown in FIGS. 5 and 6 is over-rotated, and in the embodiment, the brake blower 6 is used.
The magnitude of the braking force PS of 0 corresponds to the overshoot D shown in FIG.

Therefore, even when the power turbine 7 is rotated in the reverse direction when the power turbine 7 is rotated in the reverse direction, the brake blower 60 functions to prevent the rotation, and the reliability and durability of the brake are greatly improved.

By the way, when the brake blower 61 is hydraulically controlled by the controller 42, as shown in FIG. 3, a hydraulic friction clutch 70 is provided on the transmission shaft 68, and the hydraulic friction clutch 70 is opened / closed by an opening / closing valve 71. Is connected to the hydraulic oil passage 39, and the opening / closing valve 71 is connected to the controller 42.
It is configured to control opening and closing with.

The control content of the controller 42 is, as shown in FIG. 4, the control content shown in FIG.

That is, in step 49, the engine speed Ne is detected, and it is determined whether the detected engine speed Ne is less than or equal to the above-described predetermined speed N. If YES in step 50, step 51 in which the on-off valve 71 is kept closed is executed.
If NO, step 52 of opening the opening / closing valve 71 is executed.
Then, the hydraulic oil operates the hydraulic friction clutch 70 to drive the brake blower 60, and the crankshaft 16 is braked.

Note that the sensor 41 and the controller 42 can also warn the driver (alarm buzzer / alarm lamp) when the power turbine 7 is over-rotating, and these alarms are activated before the over-rotation. Therefore, it is naturally possible to drive the brake blower independently.

[Effects of the Invention] As is clear from the above description, according to the present invention, the following excellent effects are exhibited.

Since the crankshaft can be reliably braked by the power turbine and the brake blower, the reliability of the brake can be improved as much as possible.

[Brief description of drawings]

FIG. 1A is an overall view of a system showing a preferred embodiment of the present invention, FIG. 1B is a detailed view of essential parts of FIG. 1A, and FIG. 2 is a flowchart showing an example of control contents of a controller.
FIG. 4 is a detailed view of a main part of another embodiment, FIG. 4 is a flow chart showing the control contents of another embodiment, FIG. 5 is a braking force performance diagram, and FIG. 6 is a power turbine reversal. FIG. 7 is a braking force characteristic diagram, and FIG. 7 is a schematic diagram showing a turbo compound engine as a related technique. In the figure, 1 is an engine, 4 is an intake passage, 5 is an exhaust passage, 6
Is a turbocharger, 7 is a power turbine that also serves as a brake turbine, 8 is an exhaust bypass passage, 9 is an intake bypass passage, 11 to 14 are opening / closing valves, 16 is a crankshaft, 17 is a reversing mechanism, and 60 is a brake blower. is there.

Claims (1)

[Claims] Claim: What is claimed is: 1. A crankshaft is connected through a reversing mechanism, and when the forward rotation is switched, a driving force is transmitted to the crankshaft to recover power, and when the reversal is switched, the driving force is transmitted from the crankshaft to take in air. An engine braking device comprising: a power turbine that discharges and brakes a crankshaft; and a brake blower that is connected to the crankshaft when the power turbine is over-rotating and discharges air while discharging to brake the crankshaft. .