JP2005127143A - Engine operation controller and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine provided with a variable displacement turbocharger capable of improving acceleration performance when releasing engine brake. <P>SOLUTION: This engine operation controller has a variable blade opening detection means 36 for detecting opening of a variable guide blade of the variable displacement turbocharger 3, a number of revolution detection means Stn for detecting the number of revolutions of the turbocharger 3, detection means 8, 9 for detecting control parameters determining an operation condition of the engine 1, and a control means 10. The control means 10 sets a target region of opening of the variable guide blade. The control means determines whether the number of revolutions of the turbocharger 3 is smaller than a predetermined number or not while engine brake operates, operates the variable guide blade to a closing side when the number of revolutions of the turbocharger 3 is larger than the predetermined value and opening degree of the variable guide blade is larger than a lower limit value αa in the target region, and operates the variable guide blade to an opening side when the number of revolutions of the turbocharger 3 is smaller than the predetermined value and opening degree of the variable guide blade is smaller than an upper limit value αb in the target region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an operation control apparatus for an engine having a variable capacity turbocharger and a control method therefor, and more particularly, to accelerate by reducing the time lag until the rotation speed of the turbocharger increases when releasing the engine brake. The present invention relates to an engine control apparatus for improving performance and a control method therefor.

  In an automobile engine, a throttle mechanism is provided in an exhaust system to improve engine braking force. As means for this, a method of narrowing the flow path by providing a butterfly valve in the exhaust system, and a method of narrowing the passage area by closing the variable vanes (variable guide vanes; see FIG. 8) of the variable displacement turbocharger. There is.

  In the latter case in particular, when the passage area in the turbocharger becomes narrow, the flow of exhaust stops and the rotational speed of the turbocharger becomes very low. If the engine brake is released from that state and acceleration is attempted, the time lag until the rotational speed of the turbocharger increases increases, and the acceleration performance deteriorates.

Here, with respect to an engine auxiliary brake device for an engine equipped with a turbocharger, a technique has been proposed in which a sufficient braking force can be obtained without delay in operation (see, for example, Patent Document 1).
However, in the above proposal, the auxiliary brake device (compression pressure release type auxiliary brake device) configured to discharge the air in the cylinder in the vicinity of the compression top dead center and the variable vane of the variable displacement turbocharger (variable guide vane; The braking force is improved by applying the throttle action shown in FIG. 8), which unnecessarily complicates the system configuration and control, resulting in an increase in cost.
Japanese Patent Laid-Open No. 10-18866

  The present invention has been proposed in view of the above-described problems of the prior art. In an engine equipped with a variable displacement turbocharger, the turbo rotational speed when releasing the engine brake is increased by an inexpensive and minimal configuration. It is an object of the present invention to provide an engine control device and a control method therefor that reduce the time lag until the acceleration performance is improved.

  The engine control apparatus according to the present invention includes a variable displacement blade opening that detects an opening degree of the variable guide vane (34) in an engine (1) having a variable displacement turbocharger (3) having a variable guide vane (34). Degree detection means (36), rotation speed detection means (Stn) for detecting the rotation speed of the turbocharger (3), and detection means (8, 9) for detecting a control parameter for determining the operating state of the engine (1) ) And a control means (10), and the control means (10) is configured to set a target region for the variable guide vane opening, and the turbocharger (3) while the engine brake is operating. When the rotational speed of the turbocharger (3) is higher than the predetermined value and the variable guide blade opening is larger than the lower limit value (αa) of the target region. Close the variable guide vane The variable guide vanes are operated to the open side when the rotational speed of the turbocharger (3) is lower than a predetermined value and the variable guide vane opening is smaller than the upper limit value (αb) of the target region. (Claim 1).

  The means for detecting the control parameter includes at least one of an engine load sensor (8) for detecting engine load, an engine rotation sensor (9) for detecting engine rotation, and an accelerator opening sensor (11). It is preferable.

  The target area of the variable guide vane opening degree is a specific area on the map for each operation situation stored in the storage means (12) provided in the control means (10).

  Alternatively, the lower limit value (αa) and the upper limit value (αb) of the target area of the variable guide vane opening degree are predetermined specific values (Claim 3).

  The engine control method according to the present invention includes an opening degree detection for detecting an opening degree of the variable guide vane (34) in the engine (1) having a variable displacement turbocharger (3) having the variable guide vane (34). Means (36), rotation speed detection means (Stn) for detecting the rotation speed of the turbocharger (3), detection means (8, 9) for detecting a control parameter for determining the operating state of the engine (1), And a control means (10), wherein the control means (10) is configured to set a target region for the variable guide vane opening, and determines whether or not the engine brake is operating. (S1), a step (S5) for determining whether the rotational speed of the turbocharger (3) is lower than a predetermined value when the engine brake is operating, and the rotational speed of the turbocharger (3) is predetermined. Higher than value In step S6, it is determined whether or not the variable guide vane opening is smaller than the lower limit value (αa) of the target region. If the rotational speed of the turbocharger (3) is lower than the predetermined value, variable guidance is performed. A step (S7) for determining whether or not the blade opening is larger than an upper limit value (αb) of the target region, and the rotational speed of the turbocharger (3) is higher than a predetermined value and the variable guide blade opening. Is larger than the lower limit value (αa) of the target area, the variable guide vane (34) is operated to the closed side, the rotational speed of the turbocharger (3) is lower than the predetermined value, and the variable guide vane opening degree is the target area. The variable guide vane (34) is controlled to open to the open side when it is smaller than the upper limit value (αb) (claim 4).

  In the control method, the target area of the variable guide vane opening degree is a specific area on the map for each operation situation stored in the storage means (12) provided in the control means (10). .

  Alternatively, in the control method, the lower limit value (αa) of the target region of the variable guide blade opening and the upper limit value (αb) of the variable guide blade opening are specific points set in advance (Claim 6).

  According to the engine control apparatus and control method of the present invention having the above-described configuration and method, the engine is configured to set the target region of the variable guide vane opening, and the turbocharger ( It is determined whether the rotational speed of 3) is lower than a predetermined value, the rotational speed of the turbocharger (3) is higher than the predetermined value, and the variable guide vane opening degree is lower than the lower limit value (αa) of the target region. When the variable guide vane (34) is operated to the closed side when it is large, the rotational speed of the turbocharger (3) is lower than a predetermined value and the variable guide vane opening is smaller than the upper limit value (αb) of the target region Since the variable guide vanes (34) are controlled to operate on the open side, the time lag until the turbo speed increases when the engine brake is released is reduced, and the acceleration performance can be improved.

  In addition, there are many units attached to the normal engine except for the rotational speed detection means (Stn) for detecting the rotational speed of the turbocharger (3), which increases the assembly work and the cost increase due to the addition of a new unit. Can be suppressed.

  The best mode for carrying out the present invention will be described with reference to the accompanying drawings.

First, the first embodiment will be described with reference to FIGS. 1 to 6 and FIG. 8.
In the overall configuration diagram of FIG. 1, a variable capacity turbocharger 3 is attached to the exhaust manifold 2 side of the engine 1.

  The variable capacity turbocharger 3 includes a turbine 31 in which a turbine impeller rotates by exhaust, and a compressor 32 that is rotated by the rotation of the turbine 31 and compresses intake air by the rotation. The turbocharger 3 is provided with a rotational speed sensor Stn for detecting the rotational speed of the turbocharger 3.

  As shown in the partial detail view of FIG. 8, the turbine 31 continuously changes the flow passage cross-sectional area of the exhaust gas to the turbine blade 33 a at the outer peripheral portion of the turbine impeller 33 constituted by the plurality of turbine blades 33 a. A nozzle vane 34, which is a variable guide vane that can be operated, is configured to surround the turbine impeller 33.

The plurality of nozzle vanes 34 are not drawn clearly in the drawing, but their opening degrees are steplessly changed by an actuator (reference numeral 35 in FIG. 1).
In other words, the opening degree of the nozzle vane 34 can be freely adjusted by controlling the actuator 35, and thus the rotational speed of the turbine impeller 33 is controlled.
In FIG. 8, the nozzle vane 34 indicated by a solid line indicates a state with a large opening, and the nozzle vane 34 indicated by a broken line indicates a state with a small opening.

  Returning to FIG. 1, the compressor 32 and the intake manifold 4 of the turbocharger 3 are communicated with each other by an intake pipe 7 having an intercooler 6 for cooling intake air.

The engine 1 is provided with a load sensor 8 for detecting the engine load and an engine rotation sensor 9 for detecting the engine speed, and is connected to the control unit 10 by a signal line Li. The control unit 10 is also connected to the accelerator opening sensor 11 by a signal line Li.
The control unit 10 includes a database 12 that stores maps representing various characteristics under various operating conditions.

  The actuator 35 is connected to the control unit 10 by a control signal line Lo. Further, for example, a potentiometer 36 for detecting the opening degree of the nozzle vane is attached to the actuator 35 side or the nozzle vane 34 side, and is connected to the control unit 10 by a signal line Li.

  Here, the relationship between the opening degree (α) of the nozzle vane (variable guide vane) 34 and the rotational speed (rotational speed Nt) of the turbocharger 3 (FIG. 3; Nt diagram), and the opening degree (α) of the nozzle vane 34. And the engine braking force (Fb) (FIG. 4; Fb diagram) will be described.

FIGS. 3 and 4 are graphs showing the relationship between the opening degree of the nozzle vane 34 and the rotational speed of the turbocharger 3 and the relationship between the opening degree of the nozzle vane 34 and the engine braking force under the same operating conditions. Map).
The map shown in FIGS. 3 and 4 and the map under various operating conditions in the same manner as in FIGS. 3 and 4 are stored in the database 12 provided in the control unit 10.

  It can be seen from the map (Fb diagram) in FIG. 4 that the engine braking force is high when the nozzle vane opening is between αa and αb. From the map (Nt diagram) in FIG. 3, it can be seen that the turbo rotation speed Nt increases as the opening degree increases between the same nozzle vane opening degree αa and αb.

Therefore, in the present embodiment, a region where the nozzle vane opening degree is between αa and αb is set as a target region, a lower limit value of the target region is set as αa, and an upper limit value is set as αb.
That is, under a certain operating condition (FIGS. 3 and 4), if the region between the nozzle vane openings αa and αb is set as the target region, the engine braking force in the Fab region of FIG. 4 can be secured, and FIG. As indicated by 3, the rotation speed of the turbocharger is controlled in the upwardly rising area.

As described above, the control unit 10 is configured to set a target region in which the lower limit value αa and the upper limit value αb of the opening α of the nozzle vane 34 are set.
Then, the control unit 10 determines whether or not the rotational speed of the turbocharger 3 is lower than a predetermined value while the engine brake is operating, and the opening degree of the nozzle vane 34 is higher than the predetermined value. Is larger than the lower limit value αa (the hatched area in FIG. 5), the nozzle vane 34 is actuated to the closed side (open arrow in FIG. 5), and the rotational speed of the turbocharger 3 is lower than a predetermined value. In addition, when the opening degree of the nozzle vane 34 is smaller than the upper limit value αb (the hatched area in FIG. 6), the nozzle vane 34 is controlled to operate on the open side (open arrow in FIG. 6). ing.
By repeatedly performing such control, the rotational speed of the turbocharger 3 can be gradually brought closer to the target value.

  Next, the control method of the first embodiment will be described with reference to FIG.

  First, the control unit 10 determines whether or not the engine brake is in operation (loop in step S1). If the engine brake is in operation (YES in step S1), the control unit 10 proceeds to the next step S2. .

  In step S2, the control unit 10 sets the nozzle vane opening to an area between αa (lower limit value) and αb (upper limit value).

  Next, the control unit 10 reads the nozzle vane opening degree (step S3), and reads the rotation speed of the turbocharger (step S4).

In the next step S5, the control unit 10 determines whether or not the rotational speed of the turbocharger is lower than the target value.
If it is higher than the target value (NO in step S5), the process proceeds to step S6 (see also FIG. 5 for this route). If it is lower than the target value (YES in step S5), step S7 (FIG. 6 is also used for this route). Go to Reference).

In step S6, the control unit 10 determines whether or not the nozzle vane opening is smaller (narrower) than the lower limit value αa of the target area. If smaller (YES in step S6), the control unit 10 deviates from the target area. The process returns to S2, and the steps after S2 are repeated (redo).
On the other hand, if it is larger than the lower limit value αa (NO in step S6), a control signal is transmitted so as to move the variable blade 34 to the closed side (see the white arrow in FIG. 5) (step S8), and then step S1. Returning to step S1, the control after step S1 is repeated.

In the loop of step S7, the control unit 10 determines whether or not the opening degree of the nozzle vane 34 is larger (wide) than the upper limit value αb of the target area. If it is larger (YES in step S7), the control unit 10 deviates from the target area. Therefore, the process returns to step S2, and step S2 and subsequent steps are repeated (redo).
On the other hand, if it is smaller than the upper limit αb (NO in step S7), a control signal is transmitted (step S9) to move the nozzle vane 34 to the open side (see the white arrow in FIG. 6), and then to step S1. The control after step S1 is repeated again.

  According to the first embodiment having such a configuration and the control method, it is configured to set the target region of the nozzle vane opening, and the rotational speed of the turbocharger 3 is lower than a predetermined value while the engine brake is operating. When the rotational speed of the turbocharger 3 is higher than a predetermined value and the nozzle vane opening is larger than the lower limit value αa of the target value, the nozzle vane is operated to the closed side, and the rotational speed of the turbocharger 3 is determined. Is lower than the predetermined value and the nozzle vane opening degree is smaller than the upper limit value αb of the target area, the nozzle vane is controlled to open to the open side, so that the turbo speed at the time of releasing the engine brake increases. Acceleration performance can be improved with less time lag

  In addition, except for the rotational speed sensor (Stn) that detects the rotational speed of the turbocharger 3, there are many units attached to the normal engine, which suppresses the increase in assembly work and the high cost due to the addition of new units. I can do it.

  Next, a second embodiment will be described with reference to FIG.

  In the first embodiment of FIGS. 1 and 2, the target area of the opening degree of the nozzle vane (variable guide vane) 34 is a specific area on the map for each operation situation stored in the database 12 equipped in the control unit 10. .

On the other hand, in the second embodiment of FIG. 7, the lower limit value and the upper limit value of the opening degree of the nozzle vane 34 are set as predetermined specific values.
Therefore, in the second embodiment of FIG. 7, the database 12 and the map stored in the database 12 required in the first embodiment are omitted.
The configuration and control method other than those described above are substantially the same as those in the first embodiment, and the description thereof will be omitted.

The illustrated embodiments are merely examples, and are not intended to limit the technical scope of the present invention.
For example, although the intercooler 6 is interposed in the intake system 7 in the illustrated embodiment, the intercooler 6 may be omitted.
In the illustrated example, the engine load sensor 8 and the engine rotation sensor 9 are used as means for detecting the control parameter. However, for example, a knock sensor may be used.

The block diagram which shows the whole structure of 1st Embodiment of this invention. The flowchart which showed the control method in embodiment of this invention. The characteristic view which shows the relationship between the variable blade opening which is an example of the control map for setting the variable blade opening target at the time of implementing embodiment of this invention, and the rotation speed of a turbocharger. FIG. 4 is a characteristic diagram showing the relationship between the variable blade opening and the engine braking force in the same operating state as in FIG. 3. The characteristic diagram for demonstrating the control method in case the turbo rotation speed is higher than a target value, and a variable blade opening degree is larger than the lower limit of a setting range in control by embodiment of this invention. The characteristic diagram for demonstrating the control method in case the turbo rotation speed is lower than a target value, and a variable blade opening is smaller than the upper limit of a setting range in control by embodiment of this invention. The block diagram which shows the whole structure of 2nd Embodiment of this invention. The fragmentary sectional view which shows the action | operation of the nozzle vane (variable blade) of a capacity | capacitance variable type turbocharger.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Exhaust manifold 3 ... Variable displacement turbocharger 4 ... Intake manifold 6 ... Intercooler 7 ... Intake pipe 8 ... Load sensor 9 ... Engine rotation sensor DESCRIPTION OF SYMBOLS 10 ... Control unit 31 ... Turbine 32 ... Compressor 34 ... Nozzle vane 35 ... Actuator 36 ... Potentiometer / opening detection means

Claims (6)

In an engine having a variable displacement turbocharger provided with a variable guide vane, an opening degree detecting means for detecting the opening degree of the variable guide blade, a rotational speed detecting means for detecting the rotational speed of the turbocharger, and operation of the engine Detection means for detecting a control parameter for determining the state, and control means, and the control means is configured to set a target region of the variable guide vane opening, and the turbo brake is activated while the engine brake is operating. It is determined whether or not the number of revolutions of the charger is lower than a predetermined value, and when the number of revolutions of the turbocharger is higher than the predetermined value and the variable guide blade opening is larger than the lower limit value of the target region, the variable guide blade is When the turbocharger speed is lower than the predetermined value and the variable guide vane opening is smaller than the upper limit value of the target area, the variable guide vane is operated on the open side. Operation control system of an engine and controls the so that. 2. The engine operation control device according to claim 1, wherein the target area of the variable guide blade opening is a specific area on a map for each operation situation stored in a storage means provided in the control means. The engine operation control device according to claim 1, wherein the lower limit value and the upper limit value of the target region of the variable guide blade opening are predetermined specific values. In an engine having a variable displacement turbocharger provided with a variable guide vane, an opening degree detecting means for detecting the opening degree of the variable guide vane, a rotation speed detecting means for transferring the rotation speed of the turbocharger, and operation of the engine Detection means for detecting a control parameter for determining the state, and control means, the control means is configured to set a target area of the variable guide vane opening, and whether the engine brake is in operation A step of determining whether the rotational speed of the turbocharger is lower than a predetermined value when the engine brake is operating, and a case where the rotational speed of the turbocharger is higher than the predetermined value. Determines whether the variable guide vane opening is smaller than the lower limit value of the target area, and if the turbocharger speed is lower than the predetermined value, the variable guide vane opening is the target. A step of determining whether or not the upper limit value of the region is greater than the upper limit value, and the variable guide vane when the turbocharger rotational speed is higher than a predetermined value and the variable guide blade opening is larger than the lower limit value of the target region. Is controlled to operate the variable guide blades on the open side when the rotational speed of the turbocharger is lower than a predetermined value and the variable guide blade opening is smaller than the upper limit value of the target region. A characteristic engine operation control method. 5. The engine operation control method according to claim 4, wherein the target area of the variable guide vane opening degree is a specific area on a map for each operation state stored in a storage means provided in the control means. The engine operation control method according to claim 4, wherein the lower limit value of the target region of the variable guide blade opening and the upper limit value of the variable guide blade opening are predetermined specific values.

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