JP2010261378A - Control method of power train system and power train system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly and properly control the oxygen concentration in a combustion chamber of a diesel engine, when shifting a stepped manual transmission. <P>SOLUTION: The reduction ratio dα of a stepping quantity of an accelerator pedal 40 is calculated, and when an engine speed N1 is an optional speed of a medium speed area, a threshold value dα1 of the reduction ratio dα is set to the first reduction ratio. When the engine speed N1 is the optional speed of a low speed area or a high speed area, the threshold value dα1 of the reduction ratio is set to the second reduction ratio smaller than the first reduction ratio. When the reduction ratio dα is the threshold value dα1 or less, the oxygen concentration in the combustion chamber of the diesel engine is controlled in the first oxygen concentration calculated based on the detected engine seed N1 and request torque α1. When the reduction ratio dα is larger than the threshold value dα1, the oxygen concentration M is controlled in the second oxygen concentration having a difference of the predetermined concentration or more between the first oxygen concentration and itself when the engine speed and the request torque are the same as compared with a case of calculating the first oxygen concentration. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a powertrain system including a diesel engine and a stepped transmission, and a method for controlling the powertrain system.

  When excess oxygen burns in the combustion chamber of a diesel engine, the combustion chamber becomes excessively hot and high pressure, and the amount of NOx (nitrogen oxide) generated increases, so the oxygen concentration in the combustion chamber is controlled appropriately. There is a need. The target value of the oxygen concentration is set according to, for example, the engine speed of the engine and the required torque required for the engine. The oxygen concentration is adjusted, for example, by adjusting the flow rate (EGR amount) of exhaust gas returned from the engine exhaust passage to the intake passage via the EGR passage.

  By the way, the output of the engine is not required during gear shifting of the stepped transmission. Therefore, as shown by the solid line in FIG. 10, the target value of the oxygen concentration in the combustion chamber is set to the lowest value during the shift (time from time t1 to time t2). When the shift is completed, a new target value is set based on the engine speed and the required torque at the completion of the shift. Therefore, at the completion of the shift, the target value of the oxygen concentration is instantaneously significantly increased.

  However, it is technically extremely difficult to instantaneously change the oxygen concentration in the combustion chamber instantaneously upon completion of the shift. As indicated by the broken line in FIG. 10, the actual oxygen concentration gradually increases immediately after the completion of the shift, and thus greatly falls below the target value, resulting in insufficient oxygen in the combustion chamber.

  In view of such a problem, in the technique described in, for example, paragraph [0046] of Patent Document 1, the oxygen concentration (EGR amount) during the shift is controlled so that the oxygen shortage in the combustion chamber immediately after the shift is completed is suppressed. Be controlled. Specifically, in the technique of Patent Document 1, the oxygen concentration during the shift is maintained at a predetermined concentration according to the oxygen concentration immediately before the shift. According to such a technique, the amount of change in oxygen concentration at the completion of shifting can be minimized.

JP 2008-38624 A

  When performing oxygen concentration control during shifting as described in Patent Document 1, the oxygen concentration in the combustion chamber must be reliably set to a predetermined concentration before shifting is completed. Therefore, when shifting is performed, it is desirable to start control for maintaining the oxygen concentration during the shifting to the predetermined concentration as quickly as possible.

  For this reason, it is conceivable to start control for maintaining the oxygen concentration during the shift at the predetermined concentration when any control parameter that changes prior to the shift exceeds a predetermined threshold.

  However, in this case, depending on the method for setting the threshold value of the control parameter, the control during the shift may be started when the shift is not actually performed, or the shift is being performed. There is a concern that the oxygen concentration cannot be controlled properly because it is not started.

  SUMMARY OF THE INVENTION Accordingly, it is a basic object of the present invention to quickly and appropriately control the oxygen concentration in the combustion chamber of a diesel engine when shifting a stepped manual transmission.

In order to solve the above problems, a first invention of the present application includes a diesel engine and a stepped transmission that has a plurality of shift speeds and decelerates the output of the diesel engine at a different reduction ratio for each shift speed. A method for controlling a powertrain system comprising:
Detecting the engine speed of the diesel engine, the required torque required for the diesel engine, and the amount of depression of the accelerator pedal of the vehicle;
Calculating a rate of decrease in the amount of depression of the accelerator pedal;
The magnitude of the engine speed is set to a low speed range that is lower than the first engine speed, a high speed range that is higher than the second engine speed higher than the first engine speed, and a second engine speed higher than the first engine speed. Pre-segmenting into smaller medium speed ranges;
When the engine speed is an arbitrary speed in the medium speed range, setting a threshold value of the reduction rate to a first reduction rate;
When the engine speed is an arbitrary speed in the low speed range or the high speed range, setting the threshold value of the reduction rate to a second reduction rate smaller than the first reduction rate;
Controlling the oxygen concentration in the combustion chamber of the diesel engine to a first oxygen concentration calculated based on the detected engine speed and the required torque when the reduction rate is equal to or less than the threshold;
When the rate of decrease is greater than the threshold, the oxygen concentration is predetermined between the first oxygen concentration when the engine speed and the required torque are the same as when the first oxygen concentration is calculated. And a step of controlling to a second oxygen concentration having a difference equal to or higher than the concentration.

  In this specification, the rate of decrease in the amount of depression of the accelerator pedal means the amount by which the amount of depression of the accelerator pedal decreases per unit time.

The powertrain system control method according to the second invention of the present application is the first invention,
In the step of dividing in advance,
The first engine speed and the second engine speed are set to be smaller as the gear stage of the stepped transmission is a gear stage having a larger reduction ratio.

The powertrain system control method according to the third invention of the present application is the first or second invention,
The second oxygen concentration is higher than the first oxygen concentration.

The control method of the powertrain system according to the fourth invention of the present application is the first to third inventions,
The oxygen concentration is controlled by controlling an amount of air that passes through an exhaust gas recirculation passage communicating with an exhaust passage and an intake passage of the diesel engine and is returned from the exhaust passage to the intake passage. .

A powertrain system according to a fifth invention of the present application is:
A diesel engine,
A stepped transmission that has a plurality of shift stages and decelerates the output of the diesel engine at a different reduction ratio for each shift stage;
Engine speed detecting means for detecting the engine speed of the diesel engine;
Requested torque detection means for detecting required torque required for the diesel engine,
A depression amount detecting means for detecting the depression amount of the accelerator pedal of the vehicle;
Oxygen concentration adjusting means for adjusting the oxygen concentration in the combustion chamber of the diesel engine;
A controller for controlling the operation of the oxygen concentration adjusting means,
The controller
Calculate the decrease rate of the accelerator pedal depression amount,
The engine speed is a low speed range that is less than or equal to the first engine speed, a high speed range that is greater than or equal to the second engine speed that is greater than the first engine speed, and a second engine speed that is greater than the first engine speed. Memorize information divided into smaller medium speed range,
When the engine speed is an arbitrary speed in the medium speed range, the threshold value of the reduction rate is set to a first reduction rate,
When the engine speed is an arbitrary speed in the low speed range or the high speed range, the threshold value of the reduction rate is set to a second reduction rate smaller than the first reduction rate,
Controlling the oxygen concentration adjusting means so that the oxygen concentration becomes a first oxygen concentration calculated based on the detected engine speed and the required torque when the decrease rate is equal to or less than the threshold;
When the reduction rate is larger than the threshold, the oxygen concentration is predetermined between the first oxygen concentration when the engine speed and the required torque are the same as when the first oxygen concentration is calculated. The oxygen concentration adjusting means is controlled so that the second oxygen concentration has a difference equal to or higher than the concentration.

  According to the first invention of the present application, when the rate of decrease in the amount of depression of the accelerator pedal exceeds a threshold, the shift-specific control of the oxygen concentration in the combustion chamber of the diesel engine is anticipated to start the shift. Can be executed quickly. In addition, the threshold value of the reduction rate is set larger when the engine speed is in the middle speed range than when the engine speed is in the low speed range or the high speed range, so that the possibility of shifting is low. In this case, the oxygen concentration in the combustion chamber is increased during the low-speed range or the high-speed range where there is a high possibility of shifting while increasing the frequency at which the oxygen concentration in the combustion chamber is controlled to a concentration suitable for the driving conditions during non-shifting. The frequency with which specific control is executed can be increased. Therefore, the oxygen concentration in the combustion chamber can be controlled appropriately.

  According to the second invention of the present application, the first engine speed, which is the upper limit value in the low speed range, and the second engine speed, which is the lower limit value in the high speed range, are smaller as the reduction ratio is larger. The smaller the ratio, the larger the setting. Therefore, it is possible to appropriately control the oxygen concentration in the combustion chamber in response to the increase in the engine speed at the time of non-shift with the decrease in wheel torque, that is, the reduction ratio.

  According to the third invention of the present application, when the rate of decrease in the accelerator pedal depression amount exceeds the threshold value, the oxygen concentration in the combustion chamber is compared with the concentration calculated based on the detected engine speed and the required torque. Since the control is performed to increase the oxygen concentration, it is possible to avoid a decrease in oxygen concentration during the shift, and to prevent the combustion chamber from running out of oxygen immediately after the shift is completed.

  According to the fourth aspect of the present invention, the oxygen concentration in the combustion chamber can be controlled using the air that passes through the exhaust gas recirculation passage and is returned from the exhaust passage to the intake passage.

  According to the fifth aspect of the present application, when the rate of decrease in the accelerator pedal depression amount exceeds a threshold, the shift-specific control of the oxygen concentration in the combustion chamber of the diesel engine is anticipated to start the shift. Can be executed quickly. In addition, the threshold value of the reduction rate is set larger when the engine speed is in the middle speed range than when the engine speed is in the low speed range or the high speed range, so that the possibility of shifting is low. In this case, the oxygen concentration in the combustion chamber is increased during the low-speed range or the high-speed range where there is a high possibility of shifting while increasing the frequency at which the oxygen concentration in the combustion chamber is controlled to a concentration suitable for the driving conditions during non-shifting. The frequency with which specific control is executed can be increased. Therefore, the oxygen concentration in the combustion chamber can be controlled appropriately.

It is the schematic which shows the powertrain system which concerns on one Embodiment of this invention. It is a figure which shows the structure of the intake / exhaust system of a diesel engine. It is a block diagram which shows the control system of a powertrain system. It is a graph which shows the condition which shifts up with progress of time. It is a graph which shows the engine speed which changes according to the condition shown in FIG. It is an example of the map for setting the target value of oxygen concentration. It is a graph which shows transition of the target value of oxygen concentration under the situation shown in FIG. It is an example of the map for setting the threshold value of an accelerator opening decreasing rate. It is a flowchart which shows the flow of each process for controlling oxygen concentration. It is a graph for comparing the transition of the target value of the oxygen concentration set by the conventional control with the transition of the actual oxygen concentration.

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

  FIG. 1 shows a schematic configuration of a powertrain system 2 according to an embodiment of the present invention. The powertrain system 2 includes a diesel engine 10 and a manual stepped transmission 6. The transmission 6 has a plurality of shift stages, and transmits the output of the diesel engine 10 to the drive wheels 8 of the vehicle after decelerating the output of the diesel engine 10 with a different reduction ratio for each shift stage.

  FIG. 2 shows an embodiment of the intake / exhaust system 11 of the diesel engine 10. The intake / exhaust system 11 has an intake passage 14 through which the intake gas of the engine 10 passes and an exhaust passage 12 through which the exhaust gas of the engine 10 passes.

  The intake passage 14 is provided with an air cleaner 28 for purifying the intake gas and an intercooler 26 for cooling the intake gas. The intercooler 26 is disposed downstream of the air cleaner 28 in the intake passage 14.

  The exhaust passage 12 has a particulate filter 22 that collects soot in the exhaust gas, and a lean NOx trap that treats (traps) nitrogen oxide (NOx) in the exhaust gas and suppresses NOx emission to the outside. A catalyst (hereinafter referred to as “NOx catalyst”) 24 is provided. The NOx catalyst 24 is disposed downstream of the particulate filter 22 in the exhaust passage 12.

  The intake / exhaust system 11 is provided with an exhaust turbocharger 20, and the exhaust turbocharger 20 includes a turbine 20 a disposed in the exhaust passage 12 and a compressor 20 b disposed in the intake passage 14. The turbine 20 a is disposed upstream of the particulate filter 22 in the exhaust passage 12. The compressor 20 b is disposed downstream of the air cleaner 28 and upstream of the intercooler 26 in the intake passage 14.

  The intake / exhaust system 11 also has an EGR (Exhaust Gas Recirculation) system for returning a part of the exhaust gas of the engine 4 from the exhaust passage 12 to the intake passage 14. In the intake / exhaust system 11, for example, two EGR passages 16 and 18 for constituting the EGR system are provided across the exhaust passage 12 and the intake passage 14, respectively.

  One EGR passage 16 is a high-pressure EGR passage used to recirculate relatively high-pressure exhaust gas. The high pressure EGR passage 16 communicates the exhaust passage 12 portion upstream of the turbine 20a and the intake passage 14 portion downstream of the compressor 20b. Specifically, the high pressure EGR passage 16 communicates with the intake passage 14 at a portion downstream of the intercooler 26. The high-pressure EGR passage 16 is provided with a high-pressure EGR valve 16 a for adjusting the recirculation amount of exhaust gas passing through the passage 16 (hereinafter also referred to as “EGR amount”).

  The other EGR passage 18 is a low-pressure EGR passage that is used to recirculate a relatively low-pressure exhaust gas. The low pressure EGR passage 18 communicates the exhaust passage 12 portion downstream of the turbine 20a and the intake passage 14 portion upstream of the compressor 20b. Specifically, the low pressure EGR passage 18 communicates with the exhaust passage 12 at a portion downstream of the particulate filter 22 and upstream of the NOx catalyst 24 and downstream of the air cleaner 28 with respect to the intake passage 14. It communicates with the side part. The low pressure EGR passage 18 is provided with a low pressure EGR valve 18a for adjusting the EGR amount of exhaust gas passing through the passage 18, and an EGR cooler 18b for cooling the recirculated exhaust gas.

  The intake passage 14 is provided with a negative pressure adjusting valve 30 and a throttle valve 32.

  The negative pressure adjusting valve 30 is provided in a portion downstream of the air cleaner 28 in the intake passage 14 and upstream of a junction with the low pressure EGR passage 18. The negative pressure adjusting valve 30 is a valve that adjusts the pressure in the intake passage 14 on the upstream side of the compressor 20b, and the amount of outside air flowing into the intake passage 14 is adjusted by controlling the opening amount of the negative pressure adjusting valve 30. The When adjusting the EGR amount of the exhaust gas passing through the low pressure EGR passage 18, it is necessary to adjust the amount of outside air flowing into the intake passage 14 accordingly, so the negative pressure adjusting valve 30 is adjusted together with the opening amount of the low pressure EGR valve 18 a. The amount of opening is also adjusted.

  The throttle valve 32 is provided in a portion of the intake passage 14 downstream of the intercooler 26 and upstream of the junction with the high-pressure EGR passage 16. The throttle valve 32 is used to adjust the intake air amount of the engine 10. Since the intake air amount of the engine 10 is determined by the total amount of the intake gas passing through the throttle valve 32 and the recirculated exhaust gas passing through the high pressure EGR passage 16, the EGR amount of the exhaust gas passing through the high pressure EGR passage 16 is adjusted. At this time, the opening amount of the throttle valve 32 is adjusted together with the opening amount of the high pressure EGR valve 16a.

  Various controls relating to the diesel engine 10 and the intake / exhaust system 11 are performed by the control device 50 shown in FIG. The control device 50 controls the operations of the negative pressure adjusting valve 30, the throttle valve 32, the high pressure EGR valve 16a, the low pressure EGR valve 18a, and the fuel injection nozzle 10b of the engine 10 based on signals sent from various sensors.

  As sensors that send signals to the control device 50, for example, an accelerator opening sensor 52, an engine speed sensor 54, a gear stage sensor 60, and a clutch sensor 62 are used.

  The accelerator opening sensor 52 is a sensor that detects the depression position of the accelerator pedal 40, functions as a depression amount detection unit that detects the depression amount of the accelerator pedal 40, and a request for detecting a required torque required for the engine 10. It also functions as torque detection means. The engine speed sensor 54 is a sensor that detects the speed of the engine 10, and functions as an engine speed detecting unit that detects the engine speed of the engine 10. The gear stage sensor 60 is a sensor that detects which gear stage the transmission 6 is set to. Specifically, as the shift speed sensor 60, for example, a switch for detecting on / off of the shift operation of the transmission 6 may be provided for each shift speed. The clutch sensor 62 is a sensor that detects connection and disconnection of the clutch 4. Specifically, as the clutch sensor 62, a clutch cut switch for detecting whether or not the clutch 4 is disconnected, a clutch switch for detecting whether or not the clutch 4 is connected, or a stroke for detecting the depression position of the clutch pedal 42. Any one or more of the sensors are used.

  Hereinafter, a configuration in which the control device 50 controls the oxygen concentration M in the combustion chamber of the engine 10 will be described.

  In the present embodiment, the oxygen concentration M is controlled by controlling the EGR amount of the exhaust gas that passes through the EGR passages 16 and 18 and is returned from the exhaust passage 12 to the intake passage 14. Specifically, the oxygen concentration M decreases as the amount of EGR increases, and increases as the amount of EGR decreases.

  The EGR amount is controlled by controlling at least one of the amount of the recirculated exhaust gas that passes through the high pressure EGR passage 16 (high pressure EGR amount) or the amount of the recirculated exhaust gas that passes through the low pressure EGR passage 18 (low pressure EGR amount). Is done by.

  The exhaust gas passing through the high-pressure EGR passage 16 is returned to the combustion chamber of the engine 10 at a high temperature, whereas the exhaust gas passing through the low-pressure EGR passage 18 is cooled by the EGR cooler 18b and the intercooler 26. Returned to the combustion chamber of the engine 10. Therefore, the exhaust gas passing through the high pressure EGR passage 16 has a lower gas density than the exhaust gas passing through the low pressure EGR passage 18. Therefore, in order to lower the oxygen concentration M while maintaining the oxygen amount in the combustion chamber of the engine 10, the low pressure EGR amount may be increased.

  In controlling the oxygen concentration M, the target value MT of the oxygen concentration M is set as appropriate, and at least one of the high pressure EGR amount and the low pressure EGR amount is controlled so that the oxygen concentration M matches the target value MT.

  A configuration for setting the target value MT of the oxygen concentration M will be described with reference to FIGS.

  As shown in FIG. 4, after accelerating the vehicle during a period from time A to time B with the gear position of the transmission 6 set to the first speed, the transmission 6 is shifted to the second speed, Assume a situation in which the vehicle is accelerated during a period from time C to time D. In this case, as shown in FIG. 5, for example, the rotational speed of the engine 10 increases during acceleration at the first speed, significantly decreases during shifting, and then increases again during acceleration at the second speed.

  At this time, the fuel injection amount of the engine 10 changes according to the amount of depression of the accelerator pedal 40 by the driver during acceleration at the first speed, for example, as indicated by a broken line Xab in FIG. For example, the acceleration changes as indicated by a broken line Xcd in FIG. On the other hand, since the accelerator pedal 40 is not depressed during the shift from the first speed to the second speed, the fuel injection amount is almost zero when the clutch is engaged, and the injection amount decreases to the amount necessary for idling when the clutch is disengaged. To do.

  A configuration for setting the target value MT of the oxygen concentration M will be described while assuming the situation shown in FIGS.

  The target value MT of the oxygen concentration M is set based on the rotational speed of the engine 10 and the fuel injection amount. Specifically, for example, as indicated by a plurality of solid lines in FIG. 6, a map for setting the target value MT according to the rotational speed of the engine 10 and the fuel injection amount is stored in the control device 50 in advance. Basically, the target value MT is appropriately set based on the engine speed, the fuel injection amount, and the map. Note that a plurality of target values MT indicated by solid lines in the map of FIG.

  However, since the fuel injection amount decreases during the shift, the target value MT becomes extremely smaller than that before the shift when the target value MT is set according to the map of FIG. Further, since it is not necessary to burn the fuel in the combustion chamber of the engine 10 in the clutch connected state during the shift, conventionally, as shown by the one-dot chain line in FIG. 7, for example, the shift is being performed (from time B to time C). Target value MT was set to the lowest value. However, when the target value MT during the shift is set in this way, the target value MT instantaneously increases significantly at the time of completion of the shift (time point C). Therefore, until the actual oxygen concentration M catches up with the target value MT. There is a problem that the combustion chamber of the engine 10 becomes deficient in oxygen (see FIG. 9).

  Therefore, in the present embodiment, when it is determined that the shift is started when a predetermined condition is satisfied, the control specific to the shift of the oxygen concentration M is performed as follows. In the present embodiment, switching the gear position of the transmission 6 to the next gear position is referred to as “start of gear shifting”.

  In the control unique to the shift, the target value MT of the oxygen concentration M during the shift is not shifted when the engine speed and the fuel injection amount are the same as when the target value MT for the non-shift is set. It is set to a value having a difference of a predetermined density or more from the target value MT at the time. That is, the target value MT during the shift is set to a value different from the value calculated from the map of FIG. 6 based on the engine speed and the fuel injection amount detected during the shift, and preferably the map of FIG. Is set to a value larger than the value calculated by. As a result, as shown by the solid line in FIG. 7, the target value MT does not increase greatly at the time of completion of the shift (time point C). Therefore, when the shift is completed, the actual oxygen concentration M is quickly changed to the target value MT. And a sufficient amount of oxygen can be supplied to the combustion chamber of the engine 10. In the present embodiment, the engagement of the clutch after the shift speed is switched is referred to as “shift completion”.

  The target value MT of the oxygen concentration M during the shift is set based on a predetermined control parameter and a predetermined map or calculation formula. Specifically, for example, a map similar to that shown in FIG. 6 for setting the target value MT in accordance with the engine speed and the fuel injection amount is set in advance, and this map and control peculiar to shifting are started. It is conceivable to set the target value MT based on the engine speed and the fuel injection amount detected immediately before the start.

  However, in the present invention, the configuration for setting the target value MT during shifting is not particularly limited. For example, when starting control peculiar to shifting, the engine speed and fuel injection amount at the completion of shifting are predicted based on predetermined control parameters, and the predicted engine speed and fuel injection amount at the completion of shifting The target value MT according to the above may be set based on, for example, the map of FIG.

  Control peculiar to the shift is started when the reduction rate dα of the depression amount of the accelerator pedal 40 becomes larger than a predetermined threshold value dα1.

  For example, as shown in FIG. 8, the threshold value dα1 is set for each gear position so as to change according to the engine speed N. For each gear position, the engine speed N is a low speed range that is equal to or lower than the first engine speed Na, a high speed range that is equal to or higher than the second engine speed Nb that is higher than the first engine speed Na, and the first engine. It is divided in advance into a medium speed range that is larger than the speed Na and smaller than the second engine speed Nb. FIG. 8 shows a low speed range, a medium speed range, and a high speed range when the shift speed is the second speed, and the first engine speed Na and the first speed increase as the speed ratio is larger. The two engine speed Nb is set small. When the engine speed N is an arbitrary engine speed in the medium speed range, the threshold value dα1 is set larger than the predetermined value d1, and when the engine speed N is an arbitrary engine speed in the low speed range or the high speed range, The threshold value dα1 is set to a predetermined value d1 or less.

  Hereinafter, a specific processing flow for controlling the oxygen concentration M will be described with reference to the flowchart shown in FIG.

  First, in step S1, signals sent from various sensors are read. Specifically, the accelerator opening α1 detected by the accelerator opening sensor 52, the rotational speed N1 of the engine 10 detected by the engine rotational speed sensor 54, information on the shift speed detected by the shift speed sensor 60, and On / off information of the clutch 4 detected by the clutch sensor 62 is read. In step S1, various kinds of read information are stored.

  In the subsequent step S2, the accelerator opening reduction rate dα and the target of the fuel injection amount of the engine 10 are determined based on the accelerator opening α1 and the engine speed N1 read in step S1 according to a preset calculation formula or map. The value FP and the fuel injection timing are calculated.

  In the next step S3, based on the shift speed information read in step S1 and the engine speed N1, a threshold dα1 of the accelerator opening decrease rate is calculated using, for example, the map of FIG.

  In a succeeding step S4, it is determined whether or not the flag F is set (F = 1 is set). The flag F is set when it is determined that the accelerator opening decrease rate dα is larger than the threshold value dα1 in step S5 described later (set to F = 1), and it is determined that the shift is completed in step S11 described later. And off (set F = 0).

  If it is determined in step S4 that the flag F is not set, the process proceeds to step S5.

  In step S5, it is determined whether or not the accelerator opening decrease rate dα calculated in step S2 is larger than the threshold value dα1 calculated in step S3, that is, whether or not a shift start is expected.

  If it is determined in step S5 that the accelerator opening decrease rate dα is equal to or less than the threshold value dα1, it is predicted that a shift will not be started, and basic control is performed in steps S6 to S8.

  Specifically, in step S6, based on the accelerator opening α1 and the engine speed N1 read in step S1, a target value of the oxygen concentration M in the combustion chamber of the engine 10 is set according to, for example, a map shown in FIG. MT is calculated.

  In the subsequent step S7, a negative value is calculated based on the target value MT of the oxygen concentration M calculated in step S6, the target value FP of the fuel injection amount calculated in step S2, and the engine speed E1 read in step S1. The opening degree of the pressure regulating valve 30, the throttle valve 32, the high pressure EGR valve 16a and the low pressure EGR valve 18a is calculated.

  In further subsequent step S8, various actuators are controlled based on the control parameters calculated in steps S2 and S7. Specifically, the fuel injection nozzle 10b is controlled so that the fuel injection amount becomes the target value FP calculated in step S2 and the injection timing becomes the timing calculated in step S2, and the intake / exhaust system is controlled. The eleven valves 16a, 18a, 30, 32 are controlled to the opening calculated in step S7. As a result, the oxygen concentration M in the combustion chamber of the engine 10 is controlled to an appropriate concentration according to the operating condition during non-shifting.

  On the other hand, if it is determined in step S5 that the accelerator opening decrease rate dα is larger than the threshold value dα1, it is predicted that a shift will be started, and a flag F is set in step S9 (F = 1 is set). ).

  In the next step S10, based on the accelerator opening α1 and the engine speed N1 read in step S1 of the previous routine, the target value MT during shifting is calculated by a predetermined map or calculation formula.

  When the target value MT during shifting is calculated in step S10, the processing in step S7 and step S8 is performed as in the basic control described above. Thus, the oxygen concentration M in the combustion chamber of the engine 10 during the shift is controlled to a value close to the target value MT when the shift is completed.

  When the control of the oxygen concentration M during the shift is thus started, it is determined that the flag F is set in step S4 of the next routine.

  If it is determined in step S4 that the flag F is set, the process proceeds to step S11.

  In step S11, it is determined whether or not shifting has been completed. Specifically, it is determined whether or not the clutch 4 that has been disengaged for switching the gear position is reconnected.

  If it is determined in step S11 that the shift has been completed, the flag F is turned off in step S13 (F = 0 is set), the process proceeds to step S5, and the above-described processing is performed.

  On the other hand, if it is determined in step S11 that the shift has not been completed, the target value MT of the oxygen concentration M is fixed to the value calculated in step S10 in step S12, and then the above-described steps S7 and S8 are performed. Is processed. Thus, the oxygen concentration M in the combustion chamber of the engine 10 is maintained at a concentration close to the target value MT at the completion of the shift from when the accelerator opening decrease rate dα exceeds the threshold value dα1 until the shift is completed. When the shift is completed, there is no need to greatly increase the oxygen concentration M. Therefore, it is possible to avoid a shortage of oxygen in the combustion chamber immediately after the completion of the shift.

  While the present invention has been described with reference to the above-described embodiment, the present invention is not limited to the above-described embodiment.

2: powertrain system, 4: clutch, 6: stepped transmission, 8: wheels, 10: diesel engine, 10b: fuel injection nozzle, 11: intake and exhaust system, 12: exhaust path, 14: intake path, 16 : High pressure EGR passage, 16a: High pressure EGR valve, 18: Low pressure EGR passage, 18a: Low pressure EGR valve, 30: Negative pressure adjustment valve, 32: Throttle valve, 40: Accelerator pedal, 42: Clutch pedal, 50: Control device, 52: accelerator opening sensor, 54: engine speed sensor, 60: shift speed sensor, 62: clutch sensor.

Claims (5)

A method of controlling a powertrain system comprising a diesel engine and a stepped transmission that has a plurality of shift stages and decelerates the output of the diesel engine at a different reduction ratio for each shift stage,
Detecting the engine speed of the diesel engine, the required torque required for the diesel engine, and the amount of depression of the accelerator pedal of the vehicle;
Calculating a rate of decrease in the amount of depression of the accelerator pedal;
The magnitude of the engine speed is set to a low speed range that is lower than the first engine speed, a high speed range that is higher than the second engine speed higher than the first engine speed, and a second engine speed higher than the first engine speed. Pre-segmenting into smaller medium speed ranges;
When the engine speed is an arbitrary speed in the medium speed range, setting a threshold value of the reduction rate to a first reduction rate;
When the engine speed is an arbitrary speed in the low speed range or the high speed range, setting the threshold value of the reduction rate to a second reduction rate smaller than the first reduction rate;
Controlling the oxygen concentration in the combustion chamber of the diesel engine to a first oxygen concentration calculated based on the detected engine speed and the required torque when the reduction rate is equal to or less than the threshold;
When the rate of decrease is greater than the threshold, the oxygen concentration is predetermined between the first oxygen concentration when the engine speed and the required torque are the same as when the first oxygen concentration is calculated. And a step of controlling to a second oxygen concentration having a difference equal to or greater than the concentration. In the step of dividing in advance,
2. The powertrain system according to claim 1, wherein the first engine speed and the second engine speed are set to be smaller as the gear stage of the stepped transmission is a gear stage having a larger reduction ratio. Control method.   The method for controlling a powertrain system according to claim 1, wherein the second oxygen concentration is higher than the first oxygen concentration.   The oxygen concentration is controlled by controlling an amount of air that passes through an exhaust gas recirculation passage communicating with an exhaust passage and an intake passage of the diesel engine and is returned from the exhaust passage to the intake passage. The control method of the powertrain system in any one of Claims 1-3. A diesel engine,
A stepped transmission that has a plurality of shift stages and decelerates the output of the diesel engine at a different reduction ratio for each shift stage;
Engine speed detecting means for detecting the engine speed of the diesel engine;
Requested torque detection means for detecting required torque required for the diesel engine,
A depression amount detecting means for detecting the depression amount of the accelerator pedal of the vehicle;
Oxygen concentration adjusting means for adjusting the oxygen concentration in the combustion chamber of the diesel engine;
A controller for controlling the operation of the oxygen concentration adjusting means,
The controller
Calculate the decrease rate of the accelerator pedal depression amount,
The engine speed is a low speed range that is less than or equal to the first engine speed, a high speed range that is greater than or equal to the second engine speed that is greater than the first engine speed, and a second engine speed that is greater than the first engine speed. Memorize information divided into smaller medium speed range,
When the engine speed is an arbitrary speed in the medium speed range, the threshold value of the reduction rate is set to a first reduction rate,
When the engine speed is an arbitrary speed in the low speed range or the high speed range, the threshold value of the reduction rate is set to a second reduction rate smaller than the first reduction rate,
Controlling the oxygen concentration adjusting means so that the oxygen concentration becomes a first oxygen concentration calculated based on the detected engine speed and the required torque when the decrease rate is equal to or less than the threshold;
When the reduction rate is greater than the threshold, the oxygen concentration is predetermined between the first oxygen concentration when the engine speed and the required torque are the same as when the first oxygen concentration is calculated. A powertrain system, wherein the oxygen concentration adjusting means is controlled so that the second oxygen concentration has a difference equal to or higher than the concentration.

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