JP2007263093A - Torque control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque control device of an internal combustion engine capable of imparting a different acceleration feeling to a driver in response to an acceleration request of the driver. <P>SOLUTION: This torque control device of the internal combustion engine controls torque of the internal combustion engine so that the internal combustion engine is operated by target torque Ttrg. The torque control device of the internal combustion engine calculates request torque Tdem corresponding to an acceleration request from the driver, and sets restriction torque Tgrd corresponding to restriction of exhaust emission. The preset restriction torque Tgrd is corrected on the basis of a torque restriction factor (a) calculated in response to the size of the request torque Tdem, and its corrected torque is set as transitional restriction torque Tgrad. When the request torque Tdem becomes larger than the transitional restriction torque Tgrad, the transitional restriction torque Tgrad is set as the target torque Ttrg. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a torque control device for an internal combustion engine that controls the torque of the internal combustion engine so that the internal combustion engine is operated at a target torque.

  As a control device for controlling the fuel injection amount (torque) of the internal combustion engine, when the fuel injection amount required by the driver exceeds the smoke limit injection amount that limits the generation of smoke, this smoke limit injection amount is used to rotate the internal combustion engine. Some are set in accordance with at least one of an ascending speed, a vehicle acceleration, a ratio of the vehicle speed to the engine speed, and a gear ratio of the transmission (Patent Document 1). In addition, there are Patent Documents 2 to 4 as prior art documents related to the present invention.

JP 2002-256945 A Japanese Patent Laid-Open No. 11-36962 JP 2001-159356 A JP-A-7-158483

  In the control device of Patent Literature 1, the state in which the smoke stays in the region where smoke is easily discharged is grasped from each parameter described above, and smoke discharge is suppressed by setting the smoke limit injection amount lower than the base. However, when the fuel injection amount is limited to the smoke limit injection amount, the smoke limit injection amount is set without considering the amount of injection determined from the driver's acceleration request, so the driver feels a dead zone. In other words, during the period when the fuel injection amount is limited to the smoke limit injection amount, the fuel injection amount is uniformly limited regardless of the driver's intention to accelerate, so the driver gets a different feeling of acceleration according to the acceleration request. You may not be able to.

  Accordingly, an object of the present invention is to provide a torque control device for an internal combustion engine that can be given to different acceleration feeling drivers according to the driver's acceleration request.

  The torque control device for an internal combustion engine according to the present invention is a torque control device for an internal combustion engine that controls the torque of the internal combustion engine so that the internal combustion engine is operated at a target torque, and the required torque corresponding to the acceleration request from the driver. Required torque calculation means for calculating the restriction torque, restriction torque setting means for setting the restriction torque according to a predetermined factor, the restriction torque is corrected according to the magnitude of the request torque, and the corrected torque is converted into the transient restriction torque. And a target torque setting means for setting the transient limit torque as the target torque when the required torque is larger than the transient limit torque. The problem is solved (claim 1).

  According to this torque control device, the required torque is calculated in response to the acceleration request from the driver, the constraint torque is corrected in accordance with the required torque, and the target torque is set. For this reason, since the target torque is determined according to the required torque, it is possible to give the driver a different feeling of acceleration according to the acceleration request of the driver. The predetermined factor of the present invention is typically exhaust emission emission restriction such as smoke emission restriction, but is not necessarily limited thereto.

  In the torque control device of the present invention, the transient limit torque setting means may correct the constraint torque so that the transient limit torque falls within a range equal to or less than the constraint torque. According to this aspect, it is possible to give different acceleration feelings to the driver as long as the constraint torque corresponding to the predetermined factor is not exceeded.

  In the torque control device of the present invention, the transient limit torque setting means may correct the constraint torque so that the transient limit torque increases as the required torque increases. According to this aspect, it is possible to give the driver a large feeling of acceleration when the required torque is large and a small feeling of acceleration when the required torque is small. Therefore, the driver can obtain an acceleration feeling that matches the acceleration request.

  In the torque control device according to the present invention, the required torque calculating means calculates the required torque by specifying the acceleration request from an opening of an accelerator pedal, and the transient limit torque setting means determines the magnitude of the required torque. Alternatively, the constraint torque may be corrected according to at least one of the displacement amount of the accelerator pedal, the operation speed, the operation acceleration, and the pedaling force together with the magnitude of the required torque (claim 4). In this case, depending on the driver's accelerator pedal operation, the accelerator pedal opening degree is the same and the operation speed is different, the accelerator pedal opening degree is the same and the operation acceleration is different, or the accelerator pedal opening degree is In the same situation where the pedaling force is different, different transient limiting torques are set. For this reason, it is possible to give the driver a feeling of acceleration that reflects even the difference in the quality of the acceleration request, such as whether it is slow acceleration or rapid acceleration.

  Further, in this aspect, the transient limiting torque setting means selects an acceleration tendency according to a traveling environment of a vehicle on which the internal combustion engine is mounted, a shift stage of the transmission of the vehicle, loading information of the vehicle, and a driver. The restriction torque may be corrected in consideration of at least one of the operation states of the operation means provided in the vehicle. In this case, since the constraint torque is corrected and the transient limit torque is set from a viewpoint different from the operation state of the accelerator pedal, the intention of the driver and the acceleration feeling experienced by the driver can be highly matched.

  As described above, according to the present invention, the required torque is calculated according to the driver's acceleration request, the constraint torque is corrected according to the magnitude of the required torque, the transient limit torque is set, and the required torque is When the torque becomes larger than the transient limit torque, the transient limit torque is set to the target torque, so that it can be given to different acceleration feeling drivers according to the driver's acceleration request.

(First embodiment)
FIG. 1 shows an embodiment of an internal combustion engine to which the torque control device of the present invention is applied. The internal combustion engine 1 is mounted on a vehicle (not shown) and is configured as a reciprocating diesel engine in which a piston 3 connected to a crankshaft 4 reciprocates in a plurality of cylinders 2 (only one is shown in FIG. 1). . The internal combustion engine 1 includes an intake passage 5 and an exhaust passage 6, and an intake valve 7 and an exhaust valve 8 that open and close these are provided in the intake passage 5 and the exhaust passage 6. An injection nozzle 10 is provided above the cylinder 2 so as to face the cylinder 2. The injection nozzle 10 is connected to, for example, a common rail fuel supply device 11. The operation of the fuel supply device 11 is controlled by an engine control unit (ECU) 12, and fuel is injected from the injection nozzle 10 at an appropriate injection timing and injection period (injection amount). Thereby, the torque of the internal combustion engine 1 is appropriately controlled, and the ECU 12 functions as a torque control device of the present invention in which the torque of the internal combustion engine 1 is appropriately controlled. The ECU 12 is a computer having a configuration such as a microprocessor, a RAM, and a ROM, and signals from various sensors that detect the operating state of the internal combustion engine 1 are input to the ECU 12. FIG. 1 shows a rotational speed sensor 13 for detecting the engine rotational speed (rotational speed), an accelerator sensor 14 capable of detecting an operation state such as an opening degree, a displacement amount, a stepping speed, an acceleration, and a pedaling force of an accelerator pedal 9, and an intake. An air flow meter 15 that detects the amount of air and a vehicle speed sensor 16 that detects the speed (vehicle speed) of the vehicle are shown.

Next, torque control according to the present embodiment will be described. FIG. 2 is a flowchart showing the procedure of a control routine for torque control. The program of this control routine is stored in the ROM of the ECU 12, and when the target torque of the internal combustion engine 1 increases, in this embodiment, when the target torque increases discontinuously beyond a predetermined change amount, the ECU 12 Repeatedly. This predetermined change amount is appropriately set according to the internal combustion engine to which the present invention is applied. First, in step S <b> 1, the ECU 12 refers to an input signal from the accelerator sensor 14 and acquires an opening degree (accelerator opening degree) accp of the accelerator pedal 9. In the subsequent step S2, the ECU 12 calculates a required torque T _dem according to the accelerator opening degree accp. As shown in FIG. 3, the required torque T _dem is calculated by previously storing a map in which the required torque T _dem is related to the accelerator opening degree accp and the engine speed Ne in the ROM of the ECU 12, and refer to this map. This can be achieved. The engine speed Ne is acquired based on an input signal from the speed sensor 13. By executing step S2, the ECU 12 functions as the required torque calculation means of the present invention.

Next, in step S3, the ECU 12 sets a restriction torque T _grd according to the exhaust emission limitation (predetermined factor) such as smoke. When the torque of the internal combustion engine 1 exceeds the constraint torque T _grd , exhaust emission exceeding a specified value is _caused . That is, the constraint torque T _grd is the upper limit value of the allowable range of exhaust emission. The constraint torque T _grd can be calculated by previously storing a map correlated with the intake air amount in the ROM of the ECU 12 and referring to this map. The intake air amount is acquired from an input signal from the air flow meter 15. By executing step S3, the ECU 12 functions as a constraint torque setting unit of the present invention.

In subsequent step S4, the ECU 12 calculates a torque limiting coefficient a. The torque limit coefficient a is a correction coefficient of 1 or less, and is calculated according to the magnitude of the required torque T _dem . FIG. 4 shows a map that the ECU 12 refers to in order to calculate the torque limiting coefficient a. This map is created in advance and stored in the ROM of the ECU 12. In FIG. 4, the torque limit coefficient a is set to increase as the required torque T _dem increases below the predetermined value Tth, and is set to 1.0 when it exceeds the predetermined value Tth. In this figure, the torque limiting coefficient a is set so as to increase smoothly in a straight line, but it may be smooth in a curve or may be set discontinuously. Next, the ECU 12 sets the transient limit torque T _grad in step S5. For example, when the target torque ECU 12 stores during the execution of the routine of FIG. 2 with _{T i,} may be obtained by calculating the transient limit torque _{T grad} based on equation (1) below is ECU 12. A in equation (1) is the torque limiting coefficient calculated in step S4.

Further, using Expression (2) in which T _grd −T _i in Expression (1) is replaced with an increase amount ΔT _grd of the constraint torque T _grd that is predicted to increase until the next routine of FIG. 2 is executed, The ECU 12 may calculate the transient limit torque T _grad based on the equation (2). For calculating the increase amount ΔT _grd , for example, a map (not shown) in which the increase amount ΔT _grd is associated with the operating state of the internal combustion engine 1 such as the engine speed Ne and the intake air amount Ga is created and stored in the ROM in advance. The ECU 12 may be realized by referring to this map. Thus, by executing steps S4 and S5, the constraint torque T _grd is corrected according to the required torque T _dem , the correction result is set as the transient limit torque T _grad , and the ECU 12 sets the transient limit torque setting of the present invention. Functions as a means.

Then, ECU 12 in step S6, compared with the required torque _{T dem} transient limit torque _{T grad,} the required torque _{T dem} is equal to or greater than the transient limit torque _{T grad.} When the required torque T _dem is larger than the transient limit torque T _grad , the process proceeds to step S7, where the ECU 12 sets the transient limit torque T _grad as the target torque T _trg and stores it in the RAM. Thereby, ECU12 functions as a target torque setting means of the present invention. On the other hand, when the required torque T _dem is equal to or less than the transient limit torque T _grad , the process proceeds to step S8, where the ECU 12 sets the required torque T _dem as the target torque and stores it in the RAM.

Next, the ECU 12 calculates a command torque based on the target torque T _trg set in step S7 or S8, and operates the fuel supply device 11 so that fuel is injected with a fuel injection amount corresponding to the calculated command torque. To finish this routine.

By repeatedly executing the above routine, for example, the target torque is set as shown in FIG. Figure 5 is a internal combustion engine 1 is accelerated from the torque T _0, an exemplary procedure for changing the torque T ₀ to the torque T ₁ shown schematically. As shown in this figure, the required torque _{T dem} period _t 0 greater than transient limit torque _{T grad} is ~t _1, transient limit torque _{T grad} is set as the target torque _{T trg,} the required torque _{T dem} transient limit torque The required torque T _dem is set as the target torque T _trg during the period t ₁ to T _grad or less.

In the case where the accelerator opening is different from the case of FIG. 5, the torque limit coefficient a increases as the opening increases, and the target torque T _trg approaches the constraint torque T _grd . Therefore, the change process until the time t ₀ ~t ₁ as shown in FIG. 6 will be different depending on the accelerator opening. For this reason, at the time of acceleration of the vehicle, different acceleration feelings can be obtained according to the driver's acceleration request. On the other hand, as shown in FIG. 7, in the comparative example in which the target torque is uniformly set to the limit torque when the request torque exceeds the limit torque without correcting the limit torque according to the request torque, the accelerator opening degree Different acceleration feelings cannot be given to the driver even if they are different. In the section t _{0 to} t ₁ in which the target torque is limited to the constraint torque T _grd , the vehicle passes through the same process both when the accelerator opening is small (for example, 40%) and large (for example, 80%). When the gear position of the transmission (not shown) is low, the driver may experience a feeling of popping out compared to when the gear position is high.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. This form is the same as that of the first embodiment except for the control routine shown in FIG. Accordingly, FIG. 1 is referred to for the configuration of the internal combustion engine. In FIG. 8, the same processes as those in FIG. As shown in FIG. 8, in the present embodiment, step S1 in FIG. 2 is changed to step S10, and step S4 in FIG. 2 is changed to step S40. In step S10, the ECU 12 acquires an acceleration request A _dem in addition to the accelerator opening degree accp. The acceleration request A _dem is calculated based on various physical quantities other than the accelerator opening degree accp. For example, the acceleration request A _dem may be calculated based on the depression speed (operation speed) of the accelerator pedal 9. When the magnitude of the stepping speed is used as the basis for calculating the acceleration request A _dem , it is possible to discriminate between slow acceleration and sudden acceleration even with the same accelerator opening degree accp. The depression speed can be detected by the accelerator sensor 14 shown in FIG.

In step S40, the torque limit coefficient a is calculated based on the acceleration request A _dem acquired in step S10. As in step S4 in FIG. 2, the correction coefficient is 1 or less, and is calculated according to the magnitude of the acceleration request A _dem . The calculation of the torque limit coefficient a may be realized, for example, by previously storing a map as shown in FIG. 9 in the ROM and referring to this map by the ECU 12. The map of FIG. 9 is a map in which the torque limit coefficient a is associated with the acceleration request A _{dem. When the} acceleration request A _dem increases below the predetermined value Ath, the torque limit coefficient a is set larger. Set to 1.0. In FIG. 9, the torque limiting coefficient a is set so as to increase linearly and smoothly, but it may be smooth as a curve or may be set discontinuously.

In the next step S5, the limiting torque T _grd is corrected based on the torque limiting coefficient a thus obtained to set the transient limiting torque T _grad , and the target torque T _trg is set in the subsequent steps. (Step S7), the command torque is calculated (step S9). For this reason, it is possible to give the driver a feeling of acceleration reflecting the difference between slow acceleration and sudden acceleration. That is, as shown in FIG. 10, even when the required torque T _dem is the same, that is, when the accelerator opening degree accp is the same, the torque limit coefficient a is calculated according to the difference in the acceleration request A _dem. When the slow acceleration is requested, the target torque T _trg1 indicated by a broken line is set. On the other hand, when the driver requests the rapid acceleration, the target torque T _trg2 indicated by a one-dot chain line is set.

  This invention is not limited to the above embodiment, You may implement with a various form. The form of the internal combustion engine to which the torque control device of the present invention is applied is not particularly limited, and can be applied to a gasoline engine.

The calculation of the acceleration request A _dem is not limited to the above-described embodiment, and may be based on at least one of the displacement amount of the accelerator pedal 9, acceleration (operation acceleration), and pedal effort. It may be quantify the acceleration request A _dem an appropriate logic driver's intention is accurately reflected in the case of calculating the acceleration request A _dem a plurality of parameters. The amount of displacement of the accelerator pedal 9 is the displacement at a predetermined time. When the acceleration of the accelerator pedal 9 is detected, an acceleration peak is obtained at the initial depression of the accelerator pedal, so that an acceleration request can be estimated based on this peak. Therefore, it is possible to obtain an acceleration request earlier than when detecting the amount of displacement of the accelerator pedal 9 and the depression speed, thereby reducing response delay. Furthermore, when the depression force of the accelerator pedal 9 is detected, it is possible to detect the degree of acceleration request before the accelerator pedal 9 is displaced, so that the acceleration request is obtained more quickly than the form in which the acceleration of the accelerator pedal 9 is detected. be able to. Further, the calculation of the required torque T _dem may be based on at least one of the displacement amount of the accelerator pedal 9, the operation speed, the acceleration, and the pedal effort in addition to the accelerator opening.

In the second embodiment, it was based the calculation of the torque limiting coefficient a with an acceleration request _{A dem} instead of the requested torque _{T dem,} torque limit coefficient by utilizing the acceleration request _{A dem} with the request torque _{T dem} a may be calculated. For example, a torque limit coefficient a ₁ calculated based on the required torque T _dem and a torque limit coefficient a ₂ calculated based on the acceleration request A _dem are obtained, and these are compared to determine one of them as the transient limit torque T _{grad. May} be used to correct the constraint torque T _grd . Whether to select the torque limit coefficient a ₁ or a ₂ may be changed according to the operating state of the internal combustion engine 1, and the reference is fixed so as to select the larger or smaller one of these. It doesn't matter. Further, the torque limit coefficient a ₁ calculated based on the required torque T _dem may be corrected according to the acceleration request A _dem . For example, even if the correction coefficient b (b ≦ 1.0) is defined according to the acceleration request A _dem and the torque limit coefficient a used for setting the transient limit torque T _grad is determined as in the following equation (3). Good. Even in the above form, it is possible to give the driver a feeling of acceleration reflecting the difference between slow acceleration and sudden acceleration.

The torque limit coefficient a is different from the operation state of the accelerator pedal 9, for example, the traveling environment of the vehicle on which the internal combustion engine 1 is mounted, the speed of the transmission of the vehicle, the occupant information of the vehicle, and the acceleration tendency of the driver You may correct | amend suitably by selection etc. According to this, since the transient limit torque T _grad is set from a viewpoint different from the operation state of the accelerator pedal 9, the intention of the driver and the acceleration feeling experienced by the driver can be highly matched.

  The traveling state of the vehicle includes the road surface state where the vehicle travels, the presence or absence of traffic congestion, the inter-vehicle distance from other vehicles, and the like. For example, the torque limit coefficient a can be corrected so as to increase as the road surface gradient increases, and the torque limit coefficient a can be corrected so as to be smaller than that when the road surface is congested or the inter-vehicle distance is short. In this case, a sufficient acceleration feeling can be given to the driver when climbing, and a gentle acceleration feeling can be given to the driver when there is a traffic jam or when the inter-vehicle distance is short. The detection of whether or not it is during climbing may be realized based on the ECU 12 specifying changes in the load and vehicle speed of the internal combustion engine 1. Further, the detection of whether or not there is a traffic jam may be realized based on the magnitude of the average vehicle speed while the ECU 12 obtains the average vehicle speed for a predetermined time from the input signal of the vehicle speed sensor 16. The inter-vehicle distance can be detected based on this output signal by providing a sensor (not shown) for detecting the inter-vehicle distance from other vehicles.

  When the limiting torque coefficient a is corrected at the shift stage of the vehicle transmission device, the acceleration request at the low speed stage is higher than that at the high speed stage even at the same vehicle speed and the same operation state of the accelerator pedal 9. Therefore, correction may be made so that the limiting torque coefficient a when the speed is low is smaller than when the speed is high.

  When the limiting torque coefficient a is corrected according to the vehicle loading information, the limiting torque coefficient a may be increased as the loading amount increases. For example, even if the number of passengers or cargo increases and the total weight of the vehicle increases, a necessary acceleration feeling can be given to the driver. The load amount may be detected by calculating the total weight from the speed change (acceleration) of the vehicle and subtracting the vehicle weight prepared in advance from this total weight. The number of passengers may be detected.

  When the limit torque coefficient a is corrected by selecting the acceleration tendency by the driver, for example, it may be set according to the operation state of the driver with respect to the changeover switch (operation means) 20 shown in FIG. The change-over switch 20 displays options such as a sport mode in which a sharp acceleration feeling is obtained and a family mode in which a gentle acceleration feeling is obtained. The ECU 12 can grasp the operation state of the changeover switch 20 from an input signal input according to the operation of the changeover switch 20 of the driver, and can correct the limit torque coefficient a in accordance with the operation state of the changeover switch 20. According to this, it is possible to give an acceleration feeling that matches the driving preference of the driver.

In the above description, the limit torque coefficient a is 1 or less. However, the limit torque coefficient a can be set larger than 1. For example, when a condition that should be prioritized over the constraint torque T _grd is satisfied, such as in the case of an emergency of the vehicle, the limit torque coefficient a larger than 1 may be calculated exceptionally.

The figure which showed one Embodiment of the internal combustion engine to which the torque control apparatus of this invention was applied. The flowchart which showed the procedure of the control routine of torque control. It shows an example of a map obtained by relating the required torque T _dem the accelerator opening accp and the engine speed Ne. The figure which showed an example of the map which ECU refers in order to calculate the torque limiting coefficient a. The figure which showed typically an example of the process of a torque change. Explanatory drawing explaining the process of a torque change differing by the difference in accelerator opening. The figure which showed the comparative example of FIG. The flowchart which showed the procedure of the control routine of the torque control which concerns on 2nd Embodiment. The figure which showed an example of the map with which the torque limitation coefficient a was matched with the acceleration request _| requirement _Adem . FIG. 6 is an explanatory diagram for explaining that the process of torque change _differs according to the difference in acceleration request A _dem even when the required torque T _dem is the same.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 9 Accelerator pedal 12 ECU (Torque control device, demand torque calculation means, restriction torque setting means, transient limit torque setting means, target torque setting means)
20 changeover switch (operation means)

Claims (5)

A torque control device for an internal combustion engine that controls the torque of the internal combustion engine so that the internal combustion engine is operated at a target torque,
Request torque calculation means for calculating a request torque according to an acceleration request from a driver, restriction torque setting means for setting a restriction torque according to a predetermined factor, and correcting the restriction torque according to the magnitude of the request torque A transient limit torque setting means for setting the corrected torque as a transient limit torque, and a target torque setting for setting the transient limit torque as the target torque when the required torque is larger than the transient limit torque And a torque control device for an internal combustion engine.   2. The torque control device for an internal combustion engine according to claim 1, wherein the transient limit torque setting unit corrects the constraint torque so that the transient limit torque falls within a range equal to or less than the constraint torque.   The torque control device for an internal combustion engine according to claim 1 or 2, wherein the transient limit torque setting means corrects the constraint torque so that the transient limit torque increases as the required torque increases. The required torque calculating means calculates the required torque by specifying the acceleration request from the opening of an accelerator pedal,
The transient limit torque setting means may be in accordance with at least one of the displacement amount of the accelerator pedal, the operation speed, the operation acceleration, and the pedal force instead of the magnitude of the demand torque or together with the magnitude of the demand torque. The torque control device for an internal combustion engine according to any one of claims 1 to 3, wherein the constraint torque is corrected.   The transient limit torque setting means is provided in the vehicle so that an acceleration tendency can be selected by a traveling environment of the vehicle on which the internal combustion engine is mounted, a gear position of the transmission of the vehicle, loading information of the vehicle, and a driver. 5. The torque control device for an internal combustion engine according to claim 4, wherein the restriction torque is corrected in consideration of at least one of operation states of the operating means.

Images