Abstract:
A vehicular control apparatus that controls a device mounted on a vehicle includes: a generating means for generating respective required values of the device based on quantities of state in different units; an adjusting means for converting the required values into values in one unit and obtaining a desired value of the device based on the values in one unit; a control means for controlling the device based on the obtained, desired value; and a determining means for determining whether the vehicle is in a certain state using respective reference values set for the quantities of state, the required values, and the desired value. One of the reference values is converted into the remaining reference values in different units.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a vehicular control apparatus and method for controlling a vehicle that is provided with a power train of which driving force control is performed in which various physical quantities are used to perform the control. The present invention particularly relates to a vehicular control apparatus and method that make it possible to accurately and properly determine whether the vehicle is in an idling state. 
         [0003]    2. Description of the Related Art 
         [0004]    In the vehicle that is provided with an automatic transmission and an engine that can control the engine output torque independently of the accelerator pedal operation by the driver, there is a technical concept in which desired positive or negative driving torque is realized using the engine torque and the gear ratio of the automatic transmission. The desired positive or negative driving torque is calculated based on the depression amount of the accelerator pedal operated by the driver and the operational condition of the vehicle, etc. This concept is referred to as the “driving force control”. The control methods such as “driving force request type”, “driving force demand type”, and “torque demand type” controls are also other types of the driving force control. 
         [0005]    The torque demand type control apparatus of the engine calculates the desired torque of the engine based on the depression amount of the accelerator pedal, the engine speed, and the external loads, and controls the fuel injection amount and the air supply amount according to the calculated, desired torque. 
         [0006]    In actual operation, the torque demand type control apparatus of the engine as described above calculates the desired torque production by adding the torque loss, such as friction torque, that is the loss caused in the engine and the power train, to the required output torque, and controls the fuel injection amount and the air supply amount so as to actually produce the desired torque. 
         [0007]    According to the torque demand type control apparatus of the engine, the engine torque, which is the physical quantity that directly influences the control of the vehicle, is set as a reference value for controlling the vehicle, so that the drivability can be improved, e.g., the steering feel can be always constant. 
         [0008]    Japanese Patent Application Publication No. 2005-178626 (JP-A-2005-178626) discloses the integrated control system for a vehicle that improves the failsafe characteristics in the torque demand type control apparatus of the engine described above. The integrated control system for a vehicle includes: a plurality of control units that control the traveling state of the vehicle based on the request made by operation; and a processing unit that generates information used by each of the control units when there is a request for inhibiting operation of the vehicle in accordance with the location information of the vehicle, and outputs the generated information to each of the control units. Each control unit includes: a detection means for detecting a request for operating at least one of the control units; and a calculating means for calculating information regarding the desired control value to operate the actuator provided for each control unit using at least either of information generated by the processing unit or the operational request detected by the detection means. 
         [0009]    According to the integrated control system for a vehicle, the drive system, the brake system, and the steering system are integrated to control the vehicle. For example, the integrated control system adjusts a difference between the required driving force that is calculated based on the operation amount of the accelerator pedal operated by the driver and the required driving force calculated by the driving support system, and then calculates command values to be sent to the actuators that control the output torque of the driving power source and the gear ratio of the transmission. 
         [0010]    However, when it is determined that the vehicle is in an idling state based on a request for deceleration made by the driver, etc., the fuel-cut control, the deceleration slip control, the neutral control, and the brake control are performed. Conventionally, in many cases, whether the vehicle is in an idling state is determined based on the throttle opening degree using steps such as prediction of the idling state or estimation of a driver&#39;s intention, etc. 
         [0011]    In the driving force control, a plurality of physical quantities are used to perform control, and therefore, the determination as to whether the vehicle is in an idling state that is made based on each physical quantity becomes important in controlling vehicles. However, because different physical quantities result in different idling state determination results (that is, it is impossible to determine whether the vehicle is in an idling state using the throttle opening degree only as in the conventional manner), it may be possibly determined that the vehicle is not in an idling state although the throttle opening degree is equal to or below a predetermined opening degree which indicates that the vehicle is in an idling state. Specifically, in the driving force control in which differences among a plurality of the physical quantities are adjusted, if it is determined whether the vehicle is in an idling state based on the throttle opening degree only, differences among a plurality of the physical quantities may be adjusted under the condition where one physical quantity indicates that the vehicle is in an idling state, but another physical quantity indicates that the vehicle is not in the idling state. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention provides a vehicular control apparatus and method that can accurately and properly determine whether the vehicle is in an idling state in a vehicle in which the driving force control is performed. 
         [0013]    A vehicular control apparatus according to a first aspect of the present invention controls a device mounted on a vehicle. The control apparatus includes: a generating means for generating respective required values of the device based on quantities of state in different units; an adjusting means for converting the required values into values in one unit and obtaining a desired value of the device based on the values in one unit; a control means for controlling the device based on the obtained, desired value; and a determining means for determining whether the vehicle is in a certain state using respective reference values set for the quantities of state, the required values, and the desired value. In the control apparatus, one of the reference values is converted into the remaining reference values in different units. 
         [0014]    According to the first aspect, the driving force control is performed with, for example, the accelerator pedal operation amount as the quantity of state, the driving force as the required value, and the engine torque as the desired value, and the adjustment is made in one unit. Note that, the operation amount in this case corresponds to the throttle opening degree. When the driving force control is performed as described above, the determination as to whether the vehicle is in a certain state (e.g. idling state) is independently made using a reference value set corresponding to the quantity of state, using a reference value set corresponding to the required value, and using a reference value set corresponding to the desired value. In this case, the reference values correspond to the certain state of the vehicle, and, for example, the reference values are the quantity of state, the required value, and the desired value indicating that the vehicle is in an idling state. Therefore, if the idling state determination is made based on any of the quantity of state, the required value, and the desired value, the determination gives the same result unless the driving force control, such as the cruise control, is performed. As a result, it is possible to provide a vehicular control apparatus that can accurately determine the state of the vehicle (e.g. whether the vehicle is in an idling state) in the vehicle in which the driving force control is performed. 
         [0015]    A vehicular control apparatus according to a second aspect of the present invention is similar to that according to the first aspect, except that the device is an engine, and the certain state is an idling state. 
         [0016]    According to the second aspect, when the driving force control is performed, it is accurately and properly determined whether the vehicle is in an idling state using any of the quantity of state, the required value, and the desired value. 
         [0017]    A vehicular control apparatus according to a third aspect of the present invention is similar to that according to the second aspect, except that the reference values are values obtained through conversion performed so that the obtained values correspond to the idling state. 
         [0018]    According to the third aspect, the reference values used for determining whether the vehicle is in an idling state are the values calculated by converting the reference values corresponding to the quantity of state, the required value, and the desired value into the values that correspond to the idling state. Therefore, when the driving force control is performed, it is accurately and properly determined whether the vehicle is in an idling state using any of the quantity of state, the required value, and the desired value. 
         [0019]    A vehicular control apparatus according to a fourth aspect of the present invention is similar to those according to the first to third aspects, except that the quantity of state given as a result of operation performed by a driver of the vehicle brings about the certain state. 
         [0020]    According to the fourth aspect, when the driver of the vehicle does not depress the accelerator pedal at all, the idling state of the vehicle is brought about. Such an idling state can be accurately and properly determined using any of the quantity of state, the required value, and the desired value. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The foregoing and further objects, features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein: 
           [0022]      FIG. 1  is a control block diagram of a vehicle according to an embodiment of the invention. 
           [0023]      FIG. 2  is an operation table of an automatic transmission as shown in  FIG. 1 . 
           [0024]      FIG. 3  is a control block diagram of the routine to calculate a desired throttle opening degree, which is performed by an ECU. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    An embodiment of the present invention will be described below with reference to the attached drawings. In the description below, the same components are denoted by the same reference numeral, and the components denoted by the same reference numeral have the same name and function. Therefore, the description thereof will not be repeated. 
         [0026]    First, a power train of a vehicle including a vehicular control apparatus according to this embodiment will be described. The vehicular control apparatus according to the embodiment is realized by an electronic control unit (ECU)  1000  as shown in  FIG. 1 . In the description of the embodiment, an automatic transmission is provided with a torque converter and a planetary gear speed reduction mechanism. Further, in the embodiment, the vehicle that is provided with an engine as a power source for driving the vehicle will be described. 
         [0027]    As shown in  FIG. 1 , the power train of the vehicle includes the engine  100 , the torque converter  200 , the automatic transmission  300 , and the ECU  1000 . An output shaft of the engine  100  is connected with an input shaft of the torque converter  200 . The engine  100  and the torque converter  200  are connected to each other through a rotary shaft. Thus, a rotation speed NE of the output shaft of the engine  100  (engine speed NE) detected by an engine speed sensor  400  is equal to a rotation speed of the input shaft of the torque converter  200  (pump rotation speed). 
         [0028]    The torque converter  200  includes a lockup clutch  210 , a pump impeller  220 , a turbine runner  230 , a one-way clutch  250 , and a stator  240 . The lockup clutch  210  allows the input shaft and the output shaft to be directly coupled. The pump impeller  220  is arranged in the input shaft side, and the turbine runner  230  is arranged in the output shaft side. The stator  240  functions as a torque amplifier. The torque converter  200  and the automatic transmission  300  are connected to each other by a rotary shaft. A rotation speed NT of the output shaft of the torque converter  200  is detected by a turbine speed sensor  410 . Note that, the rotation speed NT of the output shaft of the torque converter  200  may also be referred to as a turbine speed NT, which is equal to a rotation speed NIN of the input shaft of the automatic transmission  300 . A rotation speed NOUT of the output shaft of the automatic transmission  300  is detected by an output shaft rotation speed sensor  420 . 
         [0029]      FIG. 2  is a table showing how the automatic transmission  300  operates. The table in  FIG. 2  shows which clutch elements (C 1  to C 4  in  FIG. 1 ), which brake elements (B 1  to B 4 ), and which one-way clutch elements (F 0  to F 3 ) are engaged or released in each gear. For example, in the first gear selected when the vehicle pulls away, the clutch element C 1  and the one-way clutch elements F 0 , F 3  are engaged. 
         [0030]    The ECU  1000  that controls the aforementioned power train includes an engine ECU  1010  and an electronic controlled automatic transmission (ECT)_ECU  1020 . The ECU  1010  controls the engine  100 , and the ECT_ECU  1020  controls the automatic transmission  300 . 
         [0031]    A signal indicative of the turbine speed NT is input from the turbine speed sensor  410  to the ECT_ECU  1020 , and a signal indicative of the output shaft rotation speed NOUT is input from the output shaft rotation speed sensor  420  to the ECT_ECU  1020 . Further, a signal indicative of the engine speed NE detected by the engine speed sensor  400 , and a signal indicative of a throttle opening degree detected by the throttle position sensor are input from the engine ECU  1010  to the ECT_ECU  1020 . 
         [0032]    These rotation speed sensors are arranged to face the teeth of the respective gears for detecting rotation, which are fixed to the input shaft and the output shaft of the torque converter  200  and the output shaft of the automatic transmission  300 , respectively. These rotation speed sensors can detect slight rotation of the input shaft and the output shaft of the torque converter  200  and the output shaft of the automatic transmission  300 , respectively. As the rotation speed sensors, the sensors employing, for example, a magnetic resistance element, may be used, which are generally referred to as the “semiconductor sensors”. 
         [0033]    The ECT_ECU  1020  outputs signals for controlling solenoids to linear solenoids of the automatic transmission  300 . The clutch elements (C 1  to C 4 ), the brake elements (B 1  to B 4 ), and the one-way clutch elements (F 0  to F 3 ) listed in  FIG. 2  are engaged or released according to the signals. For example, when the transmission shifts down from 6th gear to 5th gear, the engaging pressure of the clutch element C 3  is controlled so that the clutch element C 3  in the released state is engaged, and the engaging pressure of the brake element B 2  is controlled so that the brake element B 2  in the engaged state is released. Actually, the ECT_ECU  1020  outputs the solenoid control signals to the linear solenoid valves of the hydraulic circuit. The ECT_ECU  1020  calculates desired hydraulic pressures (the hydraulic pressures that produce the desired engaging pressures) described below. The ECT_ECU  1020  then calculates the hydraulic pressures to be supplied to hydraulic servos based on the calculated, desired hydraulic pressures and other values, and the calculated hydraulic pressures for the hydraulic servos are output to the solenoid valves. 
         [0034]    The hydraulic circuit includes, for example, two linear solenoid valves and a plurality of the hydraulic servos, each of which engages and releases the corresponding one of a plurality of the friction elements (clutches and brakes) that change the power transmission path of the planetary gear unit of the automatic transmission to shift the transmission among six forward gears and one reverse gear. Solenoid modulator pressure is supplied to input ports of the linear solenoid valves, and the hydraulic pressure supplied from output ports of the linear solenoid valves is supplied to hydraulic fluid chambers of pressure control valves. Line pressure is input to input ports of the pressure control valves, and the pressure regulated using the control hydraulic pressure is supplied from output ports of the pressure control valves to the hydraulic servos through shift valves as needed. 
         [0035]    The aforementioned hydraulic circuit is just an example, and in actual cases, a large number of hydraulic servos are provided corresponding to the number of the friction elements of the automatic transmission, and a large number of shift valves that change the hydraulic paths to the hydraulic servos are also provided. Further, each of the hydraulic servos includes a piston that is fitted in the cylinder in an oil tight manner using an oil seal. The piston is moved against a return spring by the regulated hydraulic pressure, supplied from the pressure control valve, that acts on a hydraulic pressure chamber, which brings an outer friction plate into contact with an inner friction member. The friction plate and the friction member of the brakes are the same as those of the clutches in structure. 
         [0036]    The ECT_ECU  1020  detects the condition of gear shifting performed based on a command signal for gear shifting, and then sends a desired engine torque signal to the engine ECU  1010 . The engine ECU  1010  calculates a desired throttle opening degree based on the desired engine torque signal so that the engine  100  produces the desired torque. Then, the engine ECU  1010  outputs a signal indicative of the desired throttle opening degree to actuators (e.g. stepping motors) of the throttle valves of the engine  100 . 
         [0037]    Referring to  FIG. 3 , the process routine for calculating the desired throttle opening degree will be described. This process routine is performed by the ECU  1000 , which serves as the vehicular control apparatus according to the embodiment. Note that the process blocks at the desired value level shown in  FIG. 3  are realized by programs executed by the ECU  1000 , that is, by the engine ECU  1010  or the ECT_ECU  1020 . 
         [0038]    An accelerator pedal operation amount-detecting section  2000  detects the operation amount of the accelerator pedal operated by a driver. Then, it is determined whether the vehicle is in an idling state based on the detected accelerator pedal operation amount. In this case, whether the vehicle is in an idling state is determined based on the driver&#39;s intention to idle the engine. If the accelerator pedal operation amount is equal to or below a first threshold, it is determined that the driver is requiring the vehicle to idle. That is, in this case, whether the vehicle is in an idling state is determined based on the accelerator pedal operation amount and the first threshold thereof. 
         [0039]    An engine torque-calculating section  2100  calculates an engine torque based on the accelerator pedal operation amount detected by the accelerator pedal operation amount-detecting section  2000 , using a predetermined map or the like. 
         [0040]    A driving force-calculating section  2200  calculates the driving force based on the engine torque calculated by the engine torque-calculating section  2100 , using a predetermined conversion formula or the like. 
         [0041]    Similarly, the driving force(s) required by the automatic driving system and/or the driving support system, and the driving force(s) required by other systems are calculated by the driving force-calculating sections  3000  and  4000 , respectively. Then, the determination as to whether the vehicle is in an idling state is independently made based on each calculated driving force. For example, the driving force(s) required by the automatic driving system and/or the driving support system are subjected to the determination using the second threshold. Because the first and second thresholds are the physical quantities that have been subjected to the unit conversion to unify the units thereof, if the driving force(s) required by the automatic driving system and/or the driving support system are equal to or below the second threshold, it is determined that the driver is requiring the vehicle to idle. 
         [0042]    A driving force-adjusting section  5000  adjusts differences among the driving force calculated by a driving force-calculating section  2200  based on the detected accelerator pedal operation amount, the driving force calculated by a driving force-calculating section  3000  that calculates the driving force required by the automatic driving system and/or the driving support system (e.g. cruise control system), and the driving force that is calculated by a driving force-calculating section  4000  that calculates other driving forces than the aforementioned driving forces. The adjustment is performed by selecting the smallest driving force among these driving forces, for example. Then, it is determined whether the vehicle is in an idling state based on the driving force obtained after the adjustment. If the driving force is equal to or below a third threshold, it is determined that the driver is requiring the vehicle to idle. That is, in this case, whether the vehicle is in an idling state is determined based on the driving force and the third threshold thereof. Note that, the phrase “determine whether the vehicle is in an idling state based on the desired vehicle state” in  FIG. 3  indicates, for example, the case where it is determined that the vehicle is in an idling state when the cruise control system makes a determination for deceleration. 
         [0043]    A driving force control section  6000  corrects the driving force obtained after the adjustment performed by the driving force-adjusting section  5000 . The driving force control section  6000  corrects the driving force obtained after the adjustment by adding or subtracting the driving force used for the damping control of the vehicle and/or the vehicle dynamics integrated management (VDIM) to or from the driving force obtained after the adjustment. 
         [0044]    An engine torque-calculating section  6100  calculates the engine torque based on the driving force corrected by the driving force control section  6000 , using a predetermined map or the like. Then, it is determined whether the vehicle is in an idling state based on the calculated engine torque. If the engine torque is equal to or below a fourth threshold, it is determined that the driver is requiring the vehicle to idle. That is, in this case, whether the vehicle is in an idling state is determined based on the engine torque and the fourth threshold thereof. However, note that the factors related to the torque variation required by the ECT are not taken into consideration when it is determined whether the vehicle is in an idling state using the engine torque. 
         [0045]    An engine torque-adjusting section  8000  adjusts differences among the engine torque calculated by the engine torque-calculating section  6100  based on the corrected driving force and the engine torque calculated by an ECT engine torque-calculating section  7000 . The ECT engine torque-calculating section  7000  calculates the engine torque so that, for example, the engine torque is reduced during the shift control in order to improve the shift feeling and durability of the friction elements. 
         [0046]    A desired throttle opening degree-calculating section  9000  calculates a desired throttle opening degree based on the engine torque obtained after the adjustment. A signal indicative of the desired throttle opening degree is supplied to the actuators (e.g. stepping motors) of the throttle valves of the engine  100 . The actuators open the throttle valves according to the desired throttle opening degree signal, and then it is determined whether the vehicle is in an idling state based on the actual throttle opening degree, which is the throttle opening degree detected by the throttle opening degree sensor. If the actual throttle opening degree is equal to or below a fifth threshold, it is determined that the driver is requiring the vehicle to idle. That is, in this case, whether the vehicle is in an idling state is determined based on the actual throttle opening degree and the fifth threshold thereof. 
         [0047]    In this way, as shown in the double line boxes in  FIG. 3 , the ECU  1000 , which corresponds to the vehicular control apparatus according to the embodiment, makes determinations in the following manners: 
         [0000]    1) in the accelerator pedal operation amount-detecting section  2000 , it is determined whether the vehicle is in an idling state based on the accelerator pedal operation amount and the first threshold thereof;
 
2) in the driving force calculating section  3000  that calculates the driving force required by the automatic driving system and/or the driving support system, it is determined whether the vehicle is in an idling state based on the calculated driving force and the second threshold thereof;
 
3) in the driving force-adjusting section  5000 , it is determined whether the vehicle is in an idling state based on the driving force and the third threshold thereof;
 
4) in the engine torque-calculating section  6100 , it is determined whether the vehicle is in an idling state based on the engine torque and the fourth threshold thereof; and
 
5) the actual throttle opening degree is detected, and it is then determined whether the vehicle is in an idling state based on the actual throttle opening degree and the fifth threshold thereof.
 
         [0048]    In summary, the determination as to whether the vehicle is in an idling state is independently made based on the first threshold, the second threshold, the third threshold, the fourth threshold, and the fifth threshold, which are set corresponding to a minimum set of four physical quantities, the accelerator pedal operation amount, the driving force, the engine torque, and the actual throttle opening degree. Note that, the first threshold corresponds to the accelerator pedal operation amount, the second and third thresholds correspond to the driving force, the fourth threshold corresponds to the engine torque, and the fifth threshold corresponds to the actual throttle opening degree. 
         [0049]    The five thresholds are set for four different physical quantities. Therefore, for example, the first, second, third, and fifth thresholds are calculated by converting the fourth threshold as a reference into values that correspond to the respective physical quantities. 
         [0050]    Thus, in the driving force control that uses various types of the physical quantities as the parameters for performing the above determination, it is possible to more accurately determine whether the vehicle is in an idling state, as compared to the conventional case where only the comparison between the actual throttle opening degree and the predetermined throttle opening degree indicating that the vehicle is in an idling state is made to determine whether the vehicle is in an idling state. 
         [0051]    Moreover, in this way, if it is determined that the vehicle is in an idling state using the physical quantities other than the actual throttle opening degree, the determination that is made using the actual throttle opening degree will also result in the determination that the vehicle is in an idling state unless the driving force control, such as the cruise control, is performed. In other words, it is guaranteed that the actual throttle opening degree indicates that the vehicle is in an idling state when it is determined that the vehicle is in an idling state using the physical quantities other than the actual throttle opening degree. 
         [0052]    The embodiment described herein is merely an example in all respects, and it should be understood that the embodiment is not limiting. The scope of the present invention is defined not by the above description but by the scope of the claims. It is intended to include all changes and modifications within the scope of the claims and the equivalents thereof.