Abstract:
A vehicle can reverse immediately after setting a no idling state in accordance with a simple operational procedure. An idle reduction control unit set the engine into a no idling state if the key switch is on, the brake is operated, the vehicle speed is zero, and the shift position is in the drive range; and restarts the engine if the braking operation is released and the shift position is in the drive range when the engine is in the no idling state. The idle reduction control unit also restarts the engine if the shift position is shifted from the drive range to the neutral range while the brake is still being operated when the engine is in the no idling state.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. national stage of application No. PCT/JP2011/074204, filed on Oct. 20, 2011. Priority under 35 U.S.C. §119(a) and 35 U.S.C. §365(b) is claimed from Japanese Patent Application No. 2010-236606 filed on Oct. 21, 2010, the disclosure of which is also incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to an idle reduction control device, a vehicle, an idle reduction method, and a computer program. 
     BACKGROUND ART 
     Idle reduction which temporarily stops an engine in an idling state when a vehicle temporarily stops due to a signal and the like with a view to reducing exhaust gas and improving fuel efficiency has been spread. In controlling the idle reduction, when a brake is operated and a vehicle speed is thus removed, the engine is controlled to automatically stop. 
     Meanwhile, in the idle reduction, when the operation of the brake is released, the engine that temporarily stopped automatically restarts and returns to a drivable state (see, for example, Patent Literature 1). The release of the brake includes a state in which pressure at which a driver steps a brake pedal is decreased up to predetermined pressure in addition to a case in which a driver&#39;s foot is completely separated from the brake pedal. 
     CITATION LIST 
     Patent Literature 
     PTL1: JP 3613970 B 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the idle reduction control in the conventional art, it is a condition that the operation of the brake is released in restarting the engine. Therefore, for example, when a driver intends to reverse just after the engine restarted from the no idling state, the driver needs once to take his/her foot off the brake pedal and restart the engine and thereafter, set a gear position to a reverse stage (R). 
     As such, in the vehicle that performs the idle reduction control in the conventional art, since the condition of restarting the engine is the release of the brake, a sequence of restarting the engine while the operation of the brake is released is required for the vehicle to reverse just after the engine restarts from the no idling state. In this case, when the vehicle stops on a hill, since releasing the operation of the brake in order to restart the engine may be dangerous, the driver is forced to perform a difficult operation. 
     The present invention has been made under this background, and an object of the present invention is to provide an idle reduction control device, a vehicle, an idle reduction control method, and a program that allows the vehicle to reverse just after an engine restarts from a no idling state by a simple and safe operating sequence. 
     Solution to Problem 
     An aspect of the present invention is directed to an idle reduction control device. In the idle reduction control device, an engine is set to a no idling state when a key switch is in an ON state, a brake is operated, thus a vehicle speed is zero and a shift position is in a drive range, and the engine is restarted when an operation of the brake is released while the engine is in the no idling state and the shift position is in the drive range, wherein the engine is restarted when the shift position is transferred from the drive range to a neutral range while the brake is still being operated when the engine is in the no idling state. 
     Further in the idle reduction control device according to the aspect of the invention, prior to executing idle reduction in a vehicle having a hill start assisting device holding braking force even though a driver releases the operation of the brake when stopping on an ascending slope, when the hill start assisting device is in an off state, the hill start assisting device may be forcibly turned on. 
     Another aspect of the present invention is directed to a vehicle. The vehicle has the idle reduction control device according the present invention, wherein the idle reduction control device is started with the start of the vehicle, and the vehicle has a switch that alternately repeats pause and restart of the idle reduction control device whenever the brake is operated. 
     In the vehicle according to the other aspect of the present invention, when the brake is operated at a strength of a predetermined value or more, a gear position may be set to a neutral stage and provided in the idle reduction and when the brake is operated at a strength less than a predetermined value, the gear position may be set to a start stage. 
     In the vehicle according to the other aspect of the present invention, when an engine is set to an idle reduction, a rotational shaft of the engine may be connected to a rotational shaft of an electric motor controlled to hold zero rotation. 
     The vehicle according to the other aspect of the present invention further includes an engine and an electric motor, wherein a hybrid vehicle is driven by an engine or an electric motor, or cooperation of the engine and the electric motor. 
     Still another aspect of the present invention is directed to an idle reduction control method for an idle reduction control device. In the idle reduction control method for an idle reduction control device, an engine is set to a no idling state when a key switch is in an ON state, a brake is operated, thus a vehicle speed is zero and a shift position is in a drive range, and the engine is restarted when an operation of the brake is released while the engine is in the no idling state and the shift position is in the drive range, wherein the engine is restarted when the shift position is transferred from the drive range to a neutral range while the brake is still being operated when the engine is in the no idling state. 
     Still another aspect of the present invention is directed to a program. The program causes an information processing device to execute a function of the idle reduction control device according the present invention. 
     Advantageous Effects of Invention 
     According to the present invention, the vehicle can reverse just after the engine restarts from the no idling state by the simple and safe operating sequence. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating an example of a structure of a hybrid vehicle according to a first embodiment. 
         FIG. 2  is a block diagram illustrating an example of a configuration of a function implemented in a hybrid ECU of  FIG. 1 . 
         FIG. 3  is a flowchart illustrating idle reduction processing of an idle reduction control unit of  FIG. 2 . 
         FIG. 4  is a flowchart illustrating engine restart processing from a no idling state of the idle reduction control unit of  FIG. 2 . 
         FIG. 5  is a block diagram illustrating an example of a structure of a hybrid vehicle according to a second embodiment. 
         FIG. 6  is a flowchart illustrating idle reduction processing of an idle reduction control unit according to the second embodiment. 
         FIG. 7  is a block diagram illustrating an example of a structure of a hybrid vehicle according to a third embodiment. 
         FIG. 8  is a timing chart illustrating an ON/OFF situation of an idle reduction function according to the third embodiment. 
         FIG. 9  is a flowchart illustrating ON/OFF processing of the idle reduction function of an idle reduction control unit according to the third embodiment. 
         FIG. 10  is a block diagram illustrating an example of a configuration of a function implemented in a hybrid ECU according to a fourth embodiment. 
         FIG. 11  is a timing chart illustrating a gear position control of a gear position control unit in idle reduction according to the fourth embodiment. 
         FIG. 12  is a flowchart illustrating idle reduction processing of an idle reduction control unit according to the fourth embodiment. 
         FIG. 13  is diagram describing a process of controlling idle reduction in the conventional art. 
         FIG. 14  is a diagram describing a process of controlling idle reduction according to a fifth embodiment. 
         FIG. 15  is a diagram illustrating a rotational speed of an engine, a rotational speed of an electric motor, a clutch state, and a current amount of the electric motor with a time elapsed in the process of controlling idle reduction in the conventional art. 
         FIG. 16  is a diagram illustrating a rotational speed of an engine, a rotational speed of an electric motor, a clutch state, and a current amount of the electric motor with a time elapsed in the process of controlling idle reduction according to the fifth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     (Preamble) 
     An object of an idle reduction control is to reduce exhaust gas and improve fuel efficiency thereby, and this is common to an object of a hybrid vehicle. Accordingly, it is useful for further reducing the exhaust gas and improving the fuel efficiency to apply the idle reduction control to the hybrid vehicle. Therefore, an example of applying the idle reduction control to the hybrid vehicle will be hereinafter described. However, the application of the idle reduction control according to an embodiment of the present invention is not limited to the hybrid vehicle. 
     First Embodiment 
     Hereinafter, a hybrid vehicle according to a first embodiment of the present invention will be described with reference to  FIGS. 1 to 4 . 
       FIG. 1  is a block diagram illustrating an example of a structure of a hybrid vehicle  1 . The hybrid vehicle  1  is one example of a vehicle. The hybrid vehicle  1  is driven by an engine (internal combustion engine)  10  and/or an electric motor  13  through a gear shift of a semi-automatic transmission and is capable of performing idle reduction at the time of temporary stop such as waiting at a red light. Note that the semi-automatic transmission is a transmission that can automatically perform a shifting operation with the same structure as a manual transmission. 
     The hybrid vehicle  1  includes an engine  10 , an engine ECU (electronic control section)  11 , a clutch  12 , an electric motor  13 , an inverter  14 , a battery  15 , a transmission  16 , a motor ECU  17 , a hybrid ECU  18 , a vehicle wheel  19 , a temporary stop switch  20 , and a shift unit  21 . Note that the transmission  16  has the aforementioned semi-automatic transmission and is operated by the shift unit  21  having a drive range (hereinafter, referred to as a D (drive) range). 
     The engine  10  as one example of the internal combustion engine is controlled by the engine ECU  11 , generates motive power to rotate a shaft by combusting gasoline, gas oil, CNG (compressed natural gas), LPG (liquefied petroleum gas), or alternative fuel therein and transfers the generated motive power to the clutch  12 . 
     The engine ECU  11  is a computer which operates in conjunction with the motor ECU  17  by following an instruction from the hybrid ECU  18  and controls the engine  10  such as a fuel injection amount or a valve timing. For example, the engine ECU  11  includes a CPU (central processing unit), an ASIC (application specific integrated circuit), a microprocessor (microcomputer), a DSP (digital signal processor), and the like, and has a computing unit, a memory, and an I/O (input/output) port, and the like therein. 
     The clutch  12  is controlled by the hybrid ECU  18  and transfers a shaft output from the engine  10  to the vehicle wheel  19  through the electric motor  13  and the transmission  16 . In other words, the clutch  12  mechanically connects a rotational shaft of the engine  10  and a rotational shaft of the electric motor  13  to each other to transfer the shaft output of the engine  10  to the electric motor  13  or breaks the mechanical connection of the rotational shaft of the engine  10  and the rotational shaft of the electric motor  13  to allow the shaft of the engine  10  and the rotational shaft of the electric motor  13  to rotate at different rotational velocities, by the control of the hybrid ECU  18 . 
     For example, the clutch  12  mechanically connects the rotational shaft of the engine  10  and the rotational shaft of the electric motor  13  to each other when the hybrid vehicle  1  is driven by the motive power of the engine  10 , and as a result, power is generated in the electric motor  13 , when the engine  10  is assisted by driving force of the electric motor  13 , and when the engine  10  is started by the electric motor  13 . 
     Further, for example, the clutch  12  breaks the mechanical connection of the rotational shaft of the engine  10  and the rotational shaft of the electric motor  13  when the engine  10  is in a stop or idling state, and the hybrid vehicle  1  is driven by the driving force of the electric motor  13 , and when the engine  10  is in the stop or idling state, the hybrid vehicle  1  is decelerated or is driven on a downhill grade, and the electric motor  13  generates power (electric power is regenerated). 
     Note that the clutch  12  differs from a clutch operated by the driver&#39;s operation of a clutch pedal, and is operated by the control of the hybrid ECU  18 . 
     The electric motor  13 , which is a so-called a motor generator, generates the motive power to rotate the shaft by electric power supplied from the inverter  14  to supply the shaft output to the transmission  16  or is power-generated by the motive power to rotate the shaft, which is supplied from the transmission  16 , and supplies the electric power to the inverter  14 . For example, when the hybrid vehicle  1  gains the speed or runs at a constant speed, the electric motor  13  generates the power for rotating the shaft to supply the shaft output to the transmission  16  in order to cause the hybrid vehicle  1  to run in cooperation with the engine  10 . Further, the electric motor  13  works as an electric generator, for example, when the electric motor  13  is driven by the engine  10 , or the hybrid vehicle  1  runs with no power, such as the hybrid vehicle  1  is decelerated or is driven on the downhill grade. In that case, electric power is generated by the power for rotating the shaft supplied from the transmission  16  and is supplied to the inverter  14  in order to charge the battery  15 . 
     The inverter  14  is controlled by the motor ECU  17 , and converts DC voltage from the battery  15  into AC voltage or converts AC voltage from the electric motor  13  into DC voltage. When the electric motor  13  generates motive power, the inverter  14  converts the DC voltage of the battery  15  into the AC voltage to supply electric power to the electric motor  13 . When the electric motor  13  generates power, the inverter  14  converts the AC voltage from the electric motor  13  into the DC voltage. In other words, in this case, the inverter  14  serves as a rectifier for supplying the DC voltage to the battery  15  and a voltage adjusting device. 
     The battery  15 , which is a chargeable and dischargeable secondary battery, supplies the electric power to the electric motor  13  through the inverter  14  when the electric motor  13  generates the motive power or is charged by the electric power generated by the electric motor  13  when the electric motor  13  generates electric power. 
     The transmission  16  has a semi-automatic transmission (not illustrated in the drawings) that selects any one of a plurality of gear ratios (shift ratios) according to a shift instruction signal from the hybrid ECU  18 , and transfers the motive power of the shifted engine  10  and/or the motive power of the electric motor  13  to the vehicle wheel  19  by switching the shift ratio. Further, when the hybrid vehicle is decelerated or is driven on the downhill grade, the transmission  16  transfers motive power from the vehicle wheel  19  to the electric motor  13 . In the semi-automatic transmission, a driver may operate the shift unit  21  to manually change a gear position to a predetermined gear stage. 
     The motor ECU  17  is the computer which operates in conjunction with the engine ECU  11  by following an instruction from the hybrid ECU  18  and controls the inverter  14  to control the electric motor  13 . For example, the motor ECU  17  includes a CPU, an ASIC, a microprocessor (microcomputer), a DSP, and the like and has a computing unit, a memory, an I/O port, and the like therein. 
     The hybrid ECU  18  is one example of the computer, and acquires accelerator opening level information, brake operation information, vehicle speed information, and gear position information acquired from the transmission  16 , and engine rotational speed information acquired from the engine ECU  11  to control the clutch  12  by referring to the information and controls the semi-automatic transmission of the transmission  16  by supplying a shift instruction signal, for hybrid driving. The hybrid ECU  18  gives a control command of the electric motor  13  and the inverter  14  to the motor ECU  17  based on the acquired SOC information of the battery  15  and other information, and gives a control command of the engine  10  to the engine ECU  11 , for hybrid driving. For example, the hybrid ECU  18  includes a CPU, an ASIC, a microprocessor (microcomputer), a DSP, and the like and has a computing unit, a memory, an I/O port, and the like therein. 
     Note that a program executed by the hybrid ECU  18  is prestored in a nonvolatile memory in the hybrid ECU  18  to be installed in the hybrid ECU  18  as the computer in advance. 
     The engine ECU  11 , the motor ECU  17 , and the hybrid ECU  18  are connected to each other by a bus based on a standard such as a CAN (control area network), and the like. 
     The vehicle wheel  19  is a driving wheel that transfers driving force to the road surface. Note that, in  FIG. 1 , only one vehicle wheel  19  is illustrated, but the hybrid vehicle  1  actually has a plurality of vehicle wheels  19 . 
     A key switch  20  is, for example, a switch which is turned on/off with a key put by a user when the user starts driving, and as the key switch  20  is turned on, each unit of the hybrid vehicle  1  starts and as the key switch  20  is turned off, each unit of the hybrid vehicle  1  stops. 
       FIG. 2  is a block diagram illustrating an example of a configuration of a function implemented in the hybrid ECU  18  that executes the program. That is, when the hybrid ECU  18  executes the programs, an idle reduction control unit  30  is implemented. The idle reduction control unit  30  serves to control the idle reduction. 
     Subsequently, processing of the idle reduction control performed by the hybrid ECU  18  that executes the program will be described with reference to flowcharts of  FIGS. 3 and 4 . The processing in the flowcharts in  FIGS. 3 and 4  is for one cycle and is repeatedly executed when the key switch  20  of the hybrid vehicle  1  is in an ON state. 
     The flowchart of  FIG. 3  illustrates the processing of the idle reduction performing control. In START, the key switch  20  of the hybrid vehicle  1  is in the ON state, the hybrid ECU  18  executes the program, the function of the idle reduction control unit  30  is implemented in the hybrid ECU  18 , and the process proceeds to step S 1 . Before START, the hybrid vehicle  1  has a driving history at a predetermined vehicle speed or more (for example, 5 km/h or more). 
     When the idle reduction is performed, the idle reduction control unit  30  determines whether the shift position is in the D range in step S 1  as illustrated in  FIG. 3 . In step S 1 , when it is determined that the shift position is in the D range, the process proceeds to step S 2 . On the other hand, in step S 1 , when it is determined that the shift position is not in the D range, the process repeats step S 1 . 
     In step S 2 , the idle reduction control unit  30  determines whether the brake is operated. In step S 2 , when it is determined that the brake is operated, the process proceeds to step S 3 . Herein, the ‘brake is operated’ means that liquid pressure (hereinafter, referred to as brake liquid pressure) of brake oil is increased by the driver&#39;s stepping of the brake pedal and is a predetermined value or more (alternately, more than a predetermined value). On the other hand, in step S 2 , when it is determined that the brake is not operated, the process returns to step S 1 . Herein, ‘brake is not operated’ means that the brake liquid pressure is decreased by the driver&#39;s opening of the brake pedal or decreasing step force, and is less than a predetermined value (alternately, a predetermined or less). 
     In step S 3 , the idle reduction control unit  30  terminates processing after performing the idle reduction control. In detail, the idle reduction control unit  30  commands the engine ECU  11  to stop the engine  10 . When the engine  10  stops, a rotational shaft of the engine  10  and a rotational shaft of the electric motor  13  are connected with each other through the clutch  12  and rotation of the engine  10  is controlled to stop in a short time by friction of the electric motor  13 . As such, when the engine  10  and the electric motor  13  are connected to each other in order to stop the engine  10 , the idle reduction control unit  30  commands the motor ECU  17  in addition to the engine ECU  11  to control the clutch  12 . 
     Subsequently, processing of restarting the engine  10  from the no idling state will be described with reference to  FIG. 4 . In START of  FIG. 4 , the key switch  20  of the hybrid vehicle  1  is in the ON state and the vehicle is under a stoppage. The idle reduction control unit  30  is implemented in the hybrid ECU  18 . 
     As illustrated in  FIG. 4 , in step S 10 , the idle reduction control unit  30  determines whether the vehicle is under the idle reduction at present and when the vehicle is under the idle reduction, the process proceeds to step S 11 . On the other hand, in step S 10 , when the vehicle is not under the idle reduction, the process repeats step S 10 . Note that ‘the vehicle is under the idle reduction’ denotes that the hybrid vehicle  1  is under the stoppage by the processing illustrated in the flowchart of  FIG. 3 . 
     In step S 11 , the idle reduction control unit  30  determines whether a current shift position is in the D range. When the current shift position is in the D range, the process proceeds to step S 12 . And, when the current shift position is not in the D range, the process proceeds to step S 13 . 
     In step S 12 , the idle reduction control unit  30  determines whether the brake is operated and when the brake is not operated, the process proceeds to step S 15 . On the other hand, in step S 12 , when the brake is operated, the process returns to step S 10 . 
     In step S 13 , the idle reduction control unit  30  determines whether a current shift position is in a neutral range (hereinafter, referred to as an N (neutral) range) and when the current shift position is in the N range, the process proceeds to step S 14 . On the other hand, when the current shift position is not in the N range, the process returns to step S 10 . 
     In step S 14 , the idle reduction control unit  30  determines whether the brake is operated and when the brake is operated, the process proceeds to step S 15 . On the other hand, in step S 14 , when the brake is not operated, the process returns to step S 10 . 
     In step S 15 , the idle reduction control unit  30  terminates the processing for one cycle after restarting the engine  10 . 
     (In Regard to Effects) 
     According to the hybrid vehicle  1 , the conditions for restarting the engine  10  from the no idling state include 2) ‘under the idle reduction’, ‘N range’, and ‘brake operated’ in addition to (1) ‘under the idle reduction’, ‘D range’, and ‘brake not operated’. 
     In the case where the conditions for restart include only the conditions of (1), when the driver intends to reverse the vehicle just after restarting the engine  10  from the no idling state, the brake needs to be stepped and the shift position needs to be operated up to a reverse position (R range) from the D range through the N range after restarting the engine  10  (step S 15 ) without operating the brake (step S 12 ) while the shift position is in the D range. Such operation is very cumbersome to the driver. In particular, since the condition for restart needs to be the state of ‘brake not operated’, the hybrid vehicle  1  may start to move along a hill when the hybrid vehicle  1  stops on the hill, which is very dangerous. The same applies even to a vehicle in the conventional art (for example, a vehicle of Patent Literature 1), which performs the idle reduction in the N range. 
     In this regard, by setting the condition of (2) as the additional condition for restart, when the driver intends to reverse the vehicle after restarting the engine  10  from the no idling state, the driver may restart the engine  10  only by setting the shift position to the N range from the D range while the state of ‘brake operated’ is continued. Thereafter, the driver operates the shift position to the reverse position (R range) from the N range and then may open the brake pedal at last. Such operation is very simple and safe to the driver. 
     As such, the hybrid vehicle  1  may reverse just after the engine  10  is restarted from the no idling state according to a simple and safe operating sequence. 
     Second Embodiment 
     A hybrid vehicle  1 A according to a second embodiment of the present invention will be described with reference to  FIGS. 5 and 6 . As illustrated in  FIG. 5 , the hybrid vehicle  1 A has a structure in which a hill start assisting device  22  is added to the hybrid vehicle  1  and will be described by using reference numerals (for example, the hybrid ECU  18 A, the idle reduction control unit  30 A, and the like) of the same system. The hill start assisting device  22  is a device disclosed in, for example, JP 6-8808 A, and is a device that holds braking force although the driver stops or weakens the operation of the brake when the hybrid vehicle  1 A stops on the hill. 
     In the hybrid vehicle  1 A, when the hybrid ECU  18 A executes a program, a function of an idle reduction control unit  30 A (not illustrated in the drawings) is implemented. The idle reduction control unit  30 A forcibly starts the hill start assisting device  22  prior to performing the idle reduction. 
     In a flowchart of  FIG. 6 , steps S 20  and S 21  are added to the flowchart of  FIG. 3 . Hereinafter, a description of the process which overlaps with the flowchart of  FIG. 3  will be omitted. That is, in step S 2 , the idle reduction control unit  30 A determines whether the brake is operated. In step S 2 , when it is determined that the brake is operated, the process proceeds to step S 20 . On the other hand, in step S 2 , when it is determined that the brake is not operated, the process returns to step S 1 . 
     In step S 20 , the idle reduction control unit  30 A determines whether the hill start assisting device  22  is valid. In step S 20 , when it is determined that the hill start assisting device  21  is valid, the process proceeds to step S 3 . On the other hand, in step S 20 , when it is determined that the hill start assisting device  22  is not valid, the process proceeds to step S 21 . 
     In step S 21 , the idle reduction control unit  30 A makes the hill start assisting device  22  be valid, and as a result, the process proceeds to step S 3 . 
     Other processes are the same as those described in  FIG. 3 . 
     (In Regard to Effects) 
     In the conventional art, when the hill start assisting device  22  is not valid, the idle reduction control is not performed. The reason will be described below. 
     When the engine  10  of the hybrid vehicle  1 A is stopped, the clutch  12  is connected and the engine  10  is stopped by regenerative torque of the electric motor  13 . As a result, a time until the engine  10  actually stops after the idle reduction control unit  30  commands execution of the idle reduction may be made short. 
     In this case, a little processing time (for example, for 1.5 seconds) is required to synchronize a rotational speed of the electric motor  13  with a rotational speed of the engine  10  at the time of connecting the clutch  12 . During the processing, a gear position is in the neutral range, and as a result, when the hill start assisting device  22  is not valid under a situation in which the hybrid vehicle  1 A is on the hill, the hybrid vehicle  1 A may start to move along the hill. Therefore, the hill start assisting device  22  needs to be valid without fail. Therefore, in the conventional art, when the hill start assisting device  22  is not valid, the idle reduction control is not performed. 
     On the contrary, according to the hybrid vehicle  1 A, when the hill start assisting device  22  is not valid, the hill start assisting device  22  may be made to be forcibly valid. As a result, a situation in which the idle reduction may not be performed as in the conventional art may be removed. 
     Third Embodiment 
     A hybrid vehicle  1 B according to a third embodiment of the present invention will be described with reference to  FIGS. 7 to 9 . As illustrated in  FIG. 7 , the hybrid vehicle  1 B has a structure in which a pause switch  23  is added to the hybrid vehicle  1  and will be described by using reference numerals (for example, the hybrid ECU  18 B, the idle reduction control unit  30 B, and the like) of the same system. The pause switch  23  is a so-called momentary switch and is a switch configured so that contacts are conducted to each other only while an operator such as a driver presses a button part of the pause switch  23 . 
     In the hybrid vehicle  1 B, the idle reduction control unit  30 B (not illustrated in the drawings) may alternately repeat pause and restart of the idle reduction function by inputting an operation of the pause switch  23  connected to the hybrid ECU  18 B. This state is illustrated in a timing chart of  FIG. 8 . The pause switch  23  is the momentary switch that is conducted only while the driver presses a push button (not illustrated in the drawings). 
     As illustrated in  FIG. 8 , when the key switch  20  of the hybrid vehicle  1 B is turned on, the idle reduction control unit  30 B turns the idle reduction function on. Thereafter, as the key switch  20  is hold in the ON state, when the pause switch  23  is operated (at the first time), the idle reduction control unit  30 B turns the idle reduction function OFF. Thereafter, when the pause switch  23  is operated (at the second time), the idle reduction control unit  30 B effectuates the idle reduction function again. Thereafter, when the pause switch  23  is operated (at the third time), the idle reduction control unit  30 B cancels the idle reduction function. When the key switch  20  is turned off in this state, the idle reduction control unit  30 B itself stops. Subsequently, when the key switch  20  is turned on, the idle reduction control unit  30 B effectuates the idle reduction function. 
     The above processing will be described in a flowchart of  FIG. 9 . In START, the key switch  20  of the hybrid vehicle  1 B is in the ON state, the function of the idle reduction control unit  30 B is implemented in the hybrid ECU  18 B, and the process proceeds to step S 30 . 
     In step S 30 , the idle reduction control unit  30 B effectuates the idle reduction function, and as a result, the process proceeds to step S 31 . 
     In step S 31 , the idle reduction control unit  30 B determines whether the pause switch  23  is operated. In step S 31 , when it is determined that the pause switch  23  is operated, the process proceeds to step S 32 . On the other hand, in step S 31 , when it is determined that the pause switch  23  is not operated, the process returns to step S 30 . 
     In step S 32 , the idle reduction control unit  30 B cancels the idle reduction function, and as a result, the process proceeds to step S 33 . 
     In step S 33 , the idle reduction control unit  30 B determines whether the pause switch  23  is operated. In step S 33 , when it is determined that the pause switch  23  is operated, the process returns to step S 30 . On the other hand, in step S 33 , when it is determined that the pause switch  23  is not operated, the process repeats step S 33 . 
     In each step, when the key switch  20  is turned off, the idle reduction control unit  30 B itself stops, and as a result, the processing ends. 
     (In Regard to Effects) 
     According to the hybrid vehicle  1 B, the driver may temporarily stop or restart the idle reduction function by operating the pause switch  23 . As a result, the ON/OFF state of the idle reduction function may be set according to a driver&#39;s demand. 
     Even when driving of the hybrid vehicle  1 B ends by turning the key switch  20  OFF while the driver stops the idle reduction function, the idle reduction function is effectuated by subsequently turning the key switch  20  ON. That is, the idle reduction function is effectuated without fail at the time of starting the driving of the hybrid vehicle  1 B. Accordingly, it is possible to avoid the hybrid vehicle  1 B from being driven for a long time while the driver leaves the idle reduction function canceled. As a result, a chance in which the idle reduction function, which is useful to reduce exhaust gas and improve fuel efficiency, is effectively used may be increased. 
     Fourth Embodiment 
     A hybrid vehicle  1 C according to a fourth embodiment of the present invention will be described with reference to  FIGS. 10 to 12 . A structure of the hybrid vehicle  1 C may be common to any one of the hybrid vehicles  1 ,  1 A, and  1 B and will be described by using the reference numerals (for example, the hybrid ECU  18 C, the idle reduction control unit  30 C, and the like) of the same system.  FIG. 10  is a block diagram illustrating a configuration of a function implemented in the hybrid ECU  18 C (not illustrated in the drawings). 
     When the hybrid ECU  18 C executes a program, an idle reduction control unit  30 C and an idle reduction gear position control unit  31  are implemented in the hybrid ECU  18 C as illustrated in  FIG. 10 . The idle reduction gear position control unit  31  serves to control the gear position according to the idle reduction control. 
     The idle reduction control unit  30 C and the idle reduction gear position control unit  31  of the hybrid vehicle  1 C set the gear position to a start stage or a neutral stage according to brake liquid pressure within a predetermined vehicle speed range just before the idle reduction. The control is illustrated in  FIG. 11 .  FIG. 11  is a relationship diagram illustrating the relationship among the vehicle speed, the brake liquid pressure, and the gear position and has the vehicle speed on a horizontal axis thereof and the brake liquid pressure on a vertical axis thereof. In  FIG. 11 , when the brake liquid pressure is c (kg/cm2) or more while the vehicle speed is a (km/h) or more and b (km/h) or less, the gear position is set to the neutral stage and when the brake liquid pressure is less than c (kg/cm2) while the vehicle speed is a (km/h) or more and b (km/h) or less, the gear position is set to the start stage. 
     In general, strengths at which the driver steps the brake pedal in deceleration at which the vehicle does not stop and deceleration to stop the vehicle are different from each other. Therefore, when the brake liquid pressure within a predetermined vehicle speed range during deceleration is a predetermined value or more, the idle reduction gear position control unit  31  determines that the driver performs the deceleration to stop the vehicle to set the gear position to the neutral stage and when the brake liquid pressure within the predetermined vehicle speed range during deceleration is less than a predetermined value, the idle reduction gear position control unit  31  determines that the driver performs the deceleration in which the vehicle does not stop to set the gear position to the start stage. 
     The above processing will be described in a flowchart of  FIG. 12 . The flowchart of  FIG. 12  additionally includes processes of steps S 40  to S 43  to the flowchart of  FIG. 3 . Hereinafter, a description of the process which overlaps with the flowchart of  FIG. 3  will be omitted. 
     As illustrated in  FIG. 12 , the idle reduction control unit  30 C determines whether the brake is operated in step S 2 . In step S 2 , when it is determined that the brake is operated, the process proceeds to step S 40 . On the other hand, in step S 2 , when it is determined that the brake is not operated, the process returns to step S 1 . 
     In step S 40 , the idle reduction gear position control unit  31  determines whether the vehicle speed of the hybrid vehicle  1 C is within a predetermined range. In step S 40 , when it is determined that the vehicle speed of the hybrid vehicle  1 C is within the predetermined range, the process proceeds to step S 41 . On the other hand, in step S 40 , when it is determined that the vehicle speed of the hybrid vehicle  1 C is not within the predetermined range, the process returns to step S 1 . 
     In step S 41 , the idle reduction gear position control unit  31  determines whether the brake liquid pressure is a predetermined value or more. In step S 41 , when it is determined that the brake liquid pressure is the predetermined value or more, the process proceeds to step S 42 . On the other hand, in step S 41 , when it is determined that the brake liquid pressure is less than the predetermined value, the process proceeds to step S 43 . 
     In step S 42 , the idle reduction gear position control section  31  sets the gear position to the neutral stage, and as a result, the process proceeds to step S 3 . 
     In step S 43 , the idle reduction gear position control unit  31  sets the gear position to the start stage, and as a result, the process proceeds to step S 3 . 
     (In Regard to Effects) 
     In the conventional art, the control is performed so that the gear position is in the start stage during deceleration. When the vehicle stops in this state, an idle reduction control process is started from when the vehicle stops. In the idle reduction control process, the gear position is set to the neutral stage from the start stage, the clutch  12  is connected by substantially synchronizing the rotational speed of the electric motor  13  with the rotational speed of the engine  10 , and the engine  10  is stopped by the friction of the electric motor  13  by allowing the electric motor  13  to generated electricity for stopping the engine. 
     On the contrary, according to the hybrid vehicle  1 C, the gear position may be set to the start stage or the neutral stage according to the brake liquid pressure within the predetermined vehicle speed range during deceleration. As a result, in case of the deceleration to stop the vehicle, the gear position may be set to the neutral stage in advance. Accordingly, the process of setting the gear position to the neutral stage from the start stage in the idle reduction control process after the hybrid vehicle  1 C stops may be omitted. As a result, the idle reduction control process may be shortened as compared with the conventional art. Therefore, exhaust gas of the hybrid vehicle  1 C may be reduced and fuel efficiency of the hybrid vehicle  1 C may be improved. 
     As a modified example thereof, in the hybrid vehicle  1 C, when the deceleration is determined to be for stopping the vehicle and the gear position is set to the neutral stage in advance, the idle reduction control process may be started prior to the stop without waiting until the vehicle completely stops thereafter. By this configuration, the hybrid vehicle  1 C may be already in the no idling state at the time when the hybrid vehicle  1 C stops, and effects of reduction in the exhaust gas and improvement of the fuel efficiency may be increased. 
     Fifth Embodiment 
     A hybrid vehicle  1 D according to a fifth embodiment of the present invention will be described with reference to  FIGS. 13 to 16 . A structure of the hybrid vehicle  1 D may be common to any one of the hybrid vehicles  1 ,  1 A, and  1 B and will be described by using the reference numerals (for example, the hybrid ECU  18 D, the idle reduction control unit  30 D, and the like) of the same system. 
       FIG. 13  is a diagram illustrating an engine stop process during idle reduction in the conventional art. In the conventional art, as illustrated in  FIG. 13 , the idle reduction is performed by three steps of processes  1  to  3 : an engine being in an idling state→synchronizing the rotational speed of the electric motor (process  1 )→connecting the clutch (process  2 )→generating electricity for stopping the engine (process  3 )→the engine stops. 
     On the contrary, the idle reduction control unit  30 D of the hybrid vehicle  1 D performs the idle reduction by two steps of processes A and B: an engine being in an idling state→controlling the electric motor into zero rotation (process A)→connecting the clutch (process B)→the engine stops, as illustrated in  FIG. 14 . Herein, in the controlling of the electric motor into zero rotation, torque of the electric motor  13  is controlled in a direction to alleviate external force when the external force to rotate a rotational shaft is applied to the rotational shaft (rotor) of the electric motor  13 . 
     (In Regard to Effects) 
       FIG. 15  is a diagram illustrating the rotational speed of the engine (top stage), the rotational speed of the electric motor (second stage from the top), a state of the clutch (third stage from the top), and a current amount of the electric motor (bottom stage) with a time elapsed in the idle reduction control in the conventional art. On the other hand,  FIG. 16  is a diagram illustrating the rotational speed of the engine (top stage), the rotational speed of the electric motor (second stage from the top), the state of the clutch (third stage from the top), and the current amount of the electric motor (bottom stage) with a time elapsed in the idle reduction control unit  30 D of the hybrid vehicle  1 D. 
     When a change in rotational speed of the engine illustrated in  FIG. 15  and a change in rotational speed of the engine illustrated in  FIG. 16  are compared with each other, it can be seen that the rotational speed of the engine illustrated in  FIG. 16  becomes zero rotation within a shorter time than the rotational speed of the engine illustrated in  FIG. 15 . 
     When a change in rotational speed of the electric motor illustrated in  FIG. 15  and a change in rotational speed of the electric motor illustrated in  FIG. 16  are compared with each other, it can be seen that the electric motor  13  rotates within an extremely short time in controlling zero rotation of the electric motor in  FIG. 16 , while the electric motor  13  rotates in the process of synchronization of the rotational speeds of the electric motors and the process of engine stop and generation in  FIG. 15 . 
     When the state of the clutch illustrated in  FIG. 15  and the state of the clutch illustrated in  FIG. 16  are compared with each other, it can be seen that a process is terminated just after the clutch connection in  FIG. 16 , while the process is continued for a while after the clutch connection in  FIG. 15 . 
     When the current amount of the electric motor illustrated in  FIG. 15  and the current amount of the electric motor illustrated in  FIG. 16  are compared with each other, it can be seen that current continuously flows in the process of synchronization of the rotational speeds of the electric motors and the process of engine stop and generation in  FIG. 15 , while a little current flows only for a short time of controlling the zero rotation of the electric motor in  FIG. 16 . 
     As a result, in the hybrid vehicle  1 D, the idle reduction process may be terminated within a shorter time than the conventional art, and effects of reduction in the exhaust gas and improvement of the fuel efficiency may be increased. As a result, a current amount consumed in the idle reduction process may be remarkably reduced. 
     Other Embodiments 
     In the aforementioned description of the flowcharts, boundaries of determination regions may be variously changed, such as setting ‘or more’ to ‘over’ and ‘less than’ to ‘or less’. 
     The engine  10  has been described as the internal combustion engine, but may be a heat engine including an external-combustion engine. 
     It has been described that the programs executed by the hybrid ECUs  18 ,  18 A,  18 B,  18 C, and  18 D are installed in the hybrid ECUs  18 ,  18 A,  18 B,  18 C, and  18 D in advance, but removable media (storing the programs) in which the program are stored are mounted on a drive (not illustrated in the drawings), and the like and the programs read from the removable media are stored in non-volatile memories in the hybrid ECUs  18 ,  18 A,  18 B,  18 C, and  18 D or programs transmitted through wired or wireless transmission media are received by a communication unit (not illustrated in the drawings) and stored in the non-volatile memory in the hybrid ECUs  18 ,  18 A,  18 B,  18 C, and  18 D to be installed in the hybrid ECUs  18 ,  18 A,  18 B,  18 C, and  18 D which are the computers. 
     Each ECU may be implemented by an ECU acquired by arranging some or all of the functions as one or an ECU acquired by further segmenting the function of each ECU may be newly formed. 
     The programs executed by the computers may be programs which are processed in time series according to a sequence described in the specification or programs which are processed in parallel or at a required timing such as the time when calling is performed. 
     The embodiment of the present invention is not limited to the aforementioned embodiments and may be variously changed within a scope without departing from the gist of the present invention.