WO2009022511A1

WO2009022511A1 - Control apparatus and control method for vehicle

Info

Publication number: WO2009022511A1
Application number: PCT/JP2008/062645
Authority: WO
Inventors: Kazumitsu Sugano; Koji Hattori; Koji Oshima
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2007-08-10
Filing date: 2008-07-07
Publication date: 2009-02-19
Also published as: CN101784777A; EP2191121A1; JP4784574B2; CN101784777B; JP2009041525A

Abstract

An ECU executes a program including the steps of: when there is a downshift instruction of an automatic transmission (YES in S100) and a vehicle is in a driven state (YES in S102), outputting (S104) to a supply pump a control signal corresponding to a common rail instruction pressure; and when a predetermined time has elapsed from the downshift instruction (YES in S106), executing (S108) fuel injection control.

Description

DESCRIPTION

Control Apparatus and Control Method for Vehicle

Technical Field

The present invention relates to a control apparatus for a vehicle equipped with a common rail type diesel engine and a gear type automatic transmission, and in particular, to control of fuel pressure in a common rail in a downshift mode during deceleration. Background Art Conventionally, in a vehicle equipped with an internal combustion engine and an automatic transmission, a technique of increasing an output of the engine in a power-off downshift mode is known.

For example, Japanese Patent Laying-Open No. 7-229432 discloses an engine control apparatus for a vehicle equipped with an automatic transmission, which effectively increases an engine output while preventing problems such as misfire of the engine in a power-off downshift mode, thereby reducing the shifting shock and shifting time. The engine control apparatus executes control of increasing an intake air amount taken into the engine and also executes control of cutting fuel under a prescribed condition, in the power-off downshift mode of the automatic transmission. The engine control apparatus includes: means for detecting an engine load; means for detecting an engine rotation speed; means for calculating a fuel injection amount to be injected based on the engine load and the engine rotation speed; means for determining whether or not the calculated fuel injection amount is at least a prescribed value; and under a condition where the intake air amount must be increased and fuel cut must be performed, means for performing the control of increasing the intake air amount by priority, performing also the fuel cut control if the calculated fuel injection amount is smaller than a prescribed value, and stopping the fuel cut control and executing the fuel injection if the calculated fuel injection amount is not smaller than a prescribed value. According to the engine control apparatus disclosed in the above-described publication, since the engine output can efficiently be increased in the power-off downshift mode, shifting shock can be reduced, and also shifting time or the load of the frictional engagement apparatus can efficiently be reduced. Furthermore, since unstable combustion or misfire will not be invited, deterioration of heating of catalyst or exhaust gas components associated with such problems will not occur either.

Further, there is also known a diesel engine having a common rail type fuel injection system. In the common rail type fuel injection system, fuel pressurized by a high-pressure fuel pump is stored in the common rail that is a pressure accumulation chamber. High-pressure fuel is injected into the combustion chamber of each cylinder in the diesel engine from the common rail by opening/closing an electromagnetic valve.

For the purpose of bringing the fuel in the internal combustion engine into a high-pressure state, a high-pressure fuel pump that drives a cylinder through a cam provided at a drive shaft coupled to a crankshaft of the internal combustion engine is employed.

Meanwhile, while the vehicle equipped with the above-described common rail type diesel engine and the gear type automatic transmission is running, if the driver manipulates the automatic transmission to provide a downshift instruction, in some cases the fuel injection control is performed during shifting, since fuel injection is stopped when the vehicle is in a driven state. Here, it is intended to shorten the shifting time by increasing the output torque of the engine by performing the fuel injection control.

However, when the vehicle is in a driven state, the pressure in the common rail is low. Therefore, even the fuel injection control is executed in accordance with the downshift instruction, the initial fuel injection amount will be insufficient if there is a response delay in the increase of the pressure in the common rail. Accordingly, the increase of the output torque of the engine is delayed, and shifting time may not be shortened.

The engine control apparatus disclosed in the above-described publication does not take into consideration of the case where the driver manipulates the automatic transmission to perform downshift. Disclosure of the Invention

An object of the present invention is to provide control apparatus and method for a vehicle that execute fuel increase control without a response delay, when the driver manipulates an automatic transmission thereby instructing downshift.

A control apparatus for a vehicle according to one aspect of the present invention is a control apparatus for a vehicle equipped with an internal combustion engine and an automatic transmission. The internal combustion engine has a fuel injection apparatus that includes a pressure accumulation chamber storing pressurized fuel, a fuel pump sending the fuel with pressure to the pressure accumulation chamber, and an injector supplying the fuel in the pressure accumulation chamber to the internal combustion engine. The control apparatus includes: means for receiving a shift instruction signal; pressure control means for controlling the fuel pump so that pressure in the pressure accumulation chamber increases, when the shift instruction signal corresponding to an instruction of downshift to the automatic transmission is received while the vehicle is in a driven state; and injection control means for controlling the injector to increase the fuel supplied to the internal combustion engine, during the downshift, According to the present invention, the pressure control means controls the fuel pump so that pressure in the pressure accumulation chamber increases, when the shift instruction signal corresponding to an instruction of downshift to the automatic transmission is received by the movement of a manipulation member (for example, a shift lever) of the automatic transmission while the vehicle is in a driven state. Thus, a response delay of the pressure in the pressure accumulation chamber at the time point of supplying fuel in an increased amount can be solved. Thus, insufficiency of the injection amount at the initial stage of fuel injection can be solved, and fuel corresponding to the state of the vehicle can be supplied to the internal combustion engine. As a result, it becomes possible to quickly increase the output torque of the internal combustion engine, thereby shortening the shifting time. Accordingly, it becomes possible to provide the control apparatus and method for the vehicle that executes fuel increase control without a response delay, when the driver manipulates the automatic transmission thereby instructing downshift.

Preferably, the control apparatus for the vehicle further includes means for detecting the pressure in the pressure accumulation chamber. The pressure control means includes setting means for setting a target pressure in the pressure accumulation chamber in accordance with a state of the vehicle, and means for controlling the fuel pump so that the detected pressure attains the target pressure.

According to the present invention, the pressure in the pressure accumulation chamber can quickly be increased to attain the target pressure before fuel is supplied to the internal combustion engine. Therefore, a response delay of the pressure in the pressure accumulation chamber at the time point of supplying fuel in an increased amount can be solved. Thus, insufficiency of the injection amount at the initial stage of fuel injection can be solved, and fuel corresponding to the state of the vehicle can be supplied to the internal combustion engine. As a result, it becomes possible to quickly increase the output torque of the internal combustion engine, thereby shortening the shifting time. Further preferably, the control apparatus for the vehicle further includes means for detecting a rotation speed of the internal combustion engine. The setting means includes means for setting the target pressure based on the detected rotation speed and a gear after the downshift.

According to the present invention, the pressure in the pressure accumulation chamber can quickly be increased to attain the target pressure being set in accordance with the downshift instruction, before fuel is supplied to the internal combustion engine. Therefore, a response delay of the pressure in the pressure accumulation chamber at the time point of supplying fuel in an increased amount can be solved. Further preferably, the injection control means includes means for controlling the injector to increase the fuel after a lapse of a predetermined time from the instruction of downshift.

According to the present invention, by increasing fuel and supplying the same to the internal combustion engine after a lapse of a predetermined time from the downshift instruction, the output of the internal combustion engine can be increased at the time point where the shift state of the automatic transmission becomes substantially neutral. Accordingly, while suppressing the sudden acceleration feeling of the vehicle caused by the output of the internal combustion engine being transmitted to the driving wheels of the vehicle, the rotation speed of the input side of the automatic transmission can be increased so that shifting quickly proceeds.

Further preferably, the automatic transmission is a gear type automatic transmission, in which a first frictional engagement element in a released state is engaged and a second frictional engagement element in an engaged state is released by hydraulic pressure supplied based on an instruction value output to a hydraulic circuit, whereby a gear after downshift is implemented. The predetermined time is at least a time from a start of shifting gears until an engagement pressure of the second frictional engagement element is reduced to be not greater than a predetermined pressure.

According to the present invention, the predetermined time is at least a time from a start of shifting gears until an engagement pressure of the second frictional engagement element is reduced to be not greater than a predetermined pressure. Therefore, by increasing fuel and supplying the same to the internal combustion engine after a lapse of a predetermined time from the downshift instruction, the output of the internal combustion engine can be increased at the time point where the shift state of the automatic transmission becomes substantially neutral. Accordingly, while suppressing the sudden acceleration feeling of the vehicle caused by the output of the internal combustion engine being transmitted to the driving wheels of the vehicle, the rotation speed of the input side of the automatic transmission can be increased so that shifting quickly proceeds.

Further preferably, the internal combustion engine is a common rail type diesel engine.

According to the present invention, by applying the present invention to a common rail type diesel engine, a response delay of the fuel injection amount can be solved, whereby shifting time can be shortened. Brief Description of the Drawings

Fig. 1 is a schematic configuration diagram showing a powertrain controlled by an ECU being a control apparatus for a vehicle according to the present embodiment. Fig. 2 is a control block diagram showing an engine controlled by the control apparatus for the vehicle according to the present embodiment.

Fig. 3 is a functional block diagram of an ECU being the control apparatus for the vehicle according to the present embodiment.

Fig. 4 is a flowchart showing a control structure of a program executed by the ECU being the control apparatus for the vehicle according to the present embodiment.

Fig. 5 is a timing chart showing an operation of the ECU being the control apparatus for the vehicle according to the present embodiment.

Best Modes for Carrying Out the Invention In the following, referring to the drawings, an embodiment of the present invention will be described. In the description below, the same elements have the same reference characters allotted. Their label and function are also identical. Therefore, detailed description thereof will not be repeated.

Referring to Fig. 1, a vehicle equipped with a control apparatus according to an embodiment of the present invention will be described. The vehicle is an FF (Front engine Front drive) vehicle. It is to be noted that the vehicle is not limited to an FF vehicle.

The vehicle includes an engine 1000, an automatic transmission 2000, a differential gear 5000, a drive shaft 6000, front wheels 7000, and an ECU (Electronic Control Unit) 8000. The control apparatus for the vehicle according to the present invention is implemented by ECU 8000,

Engine 1000 is an internal combustion engine that burns an air-fuel mixture consisting of fuel injected from an injector (not shown) and air, inside a combustion chamber of a cylinder. A piston in the cylinder is pushed down by the combustion, whereby a crankshaft is rotated. In the present embodiment, while the description is given referring to engine 1000 as a common rail type diesel engine, the engine of the present invention is not particularly limited thereto and may be any engine provided with a fuel injection apparatus constituted of: a pressure accumulation chamber storing pressurized fuel; a fuel pump sending the fuel with pressure to the pressure accumulation chamber; and an injector supplying the fuel in the pressure accumulation chamber. The detail of engine 1000 will be described later.

Automatic transmission 2000 includes a torque converter 3200, a planetary gear 3000, and a hydraulic circuit 4000. Automatic transmission 2000 implements a desired gear, thereby changing a speed so that the rotation speed of the crankshaft attains a desired rotation speed.

Automatic transmission 2000 is provided with a plurality of factional engagement elements. The frictional engagement elements include brake elements and clutch elements. Allowing the frictional engagement elements to operate in combinations respectively corresponding to first to sixth gears, gears of first to sixth gears are implemented. When shifting is performed, the frictional engagement element in an engaged state corresponding to a before-shifting gear is released, and the frictional engagement element in a released state corresponding to an after-shifting gear is engaged. Thus, shifting is achieved. The engagement control and disengagement control of the frictional engagement elements are performed using a hydraulic circuit 4000 based on a control signal from ECU 8000. More specifically, based on an instruction value output from ECU 8000 to hydraulic circuit 4000, the hydraulic pressure supplied to each factional engagement element is controlled. Thus, the engagement control and disengagement control are performed.

An input shaft of torque converter 3200 is coupled to the crankshaft of engine 1000. An output gear of automatic transmission 2000 meshes with differential gear 5000. Driveshaft 6000 is coupled to differential gear 5000 by spline-fitting or the like. Motive power is transmitted to left and right front wheels 7000 via driveshaft 6000. A vehicle speed sensor 8002, a position switch 8006 of a shift lever 8004, an accelerator pedal position sensor 8010 of an accelerator pedal 8008, a stroke sensor 8014 of a brake pedal 8012, an engine rotation speed sensor 8020, an input shaft rotation speed sensor 8022, and an output shaft rotation speed sensor 8024 are connected to ECU 8000 via a harness and the like.

Vehicle speed sensor 8002 senses the vehicle speed from the rotation speed of drive shaft 6000, and transmits a signal representing the sensed result to ECU 8000. The position of shift lever 8004 is sensed by position switch 8006, and a signal representing the sensed result is transmitted to ECU 8000. A gear of automatic transmission 2000 is automatically implemented corresponding to the position of shift lever 8004. A manipulation member for changing the shift position is not limited to shift lever 8004. Additionally, in the present embodiment, automatic transmission 2000 has an automatic shift mode in which shifting is automatically performed in accordance with the running state of the vehicle and a manual shift mode in which an arbitrary gear is selected in accordance with the driver's manipulation.

Accelerator pedal position sensor 8010 senses the position of accelerator pedal 8008, and transmits a signal representing the sensed result to ECU 8000. Stroke sensor 8014 senses the stroke level of brake pedal 8012, and transmits a signal representing the sensed result to ECU 8000.

Engine rotation speed sensor 8020 senses the rotation speed of the output shaft (crankshaft) of engine 1000, and transmits a signal representing the sensed result to ECU 8000. Input shaft rotation speed sensor 8022 senses the input shaft rotation speed (hereinafter also referred to as turbine rotation speed) NT of automatic transmission 2000, and transmits a signal representing the sensed result to ECU 8000. Output shaft rotation speed sensor 8024 senses output shaft rotation speed NO of automatic transmission 2000, and transmits a signal representing the sensed result to ECU 8000, It is to be noted that the output shaft of engine 1000 is coupled to the input shaft of torque converter 3200. Therefore, the output shaft rotation speed of engine 1000 is equal to the input shaft rotation speed of torque converter 3200. Additionally, the output shaft of torque converter 3200 is connected to the input shaft of planetary gear unit 3000, and therefore the input shaft rotation speed of planetary gear unit 3000 is equal to the output shaft rotation speed of torque converter 3200.

ECU 8000 controls equipment such that the vehicle is in a desired running state, based on signals sent from vehicle speed sensor 8002, position switch 8006, accelerator pedal position sensor 8010, stroke sensor 8014, engine rotation speed sensor 8020, input shaft rotation speed sensor 8022, output shaft rotation speed sensor 8024, and the like as well as on a map and a program stored in ROM (Read Only Memory).

In the present embodiment, when D (drive) range is selected as the shift range of automatic transmission 2000 based on that shift lever 8004 is positioned in D (drive) position, ECU 8000 controls automatic transmission 2000 such that any gear out of first to sixth gears is implemented based on the running state (the vehicle speed and the accelerator pedal position) and a shift map stored in ROM or the like. By implementing any gear out of first to sixth gears, automatic transmission 2000 can transmit drive force to front wheels 7000.

When shift lever 8004 is manipulated so as to shift to an upshift-side gear while the manual mode is selected, ECU 8000 controls automatic transmission 2000 such that a gear that is on one step fast-speed side than the current gear is implemented.

Alternatively, when shift lever 8004 is manipulated so as to shift to a downshift- side gear while the manual mode is selected, ECU 8000 controls automatic transmission 2000 such that a gear that is on one step low-speed side than the current gear is implemented.

When N (neutral) range is selected as the shift range of automatic transmission 2000 based on that shift lever 8004 is in N (neutral) position, automatic transmission 2000 is controlled such that a neutral state (motive power blocked state) is attained. When L range is selected as the shift range of automatic transmission 2000 based on that shift lever 8004 is in L position, automatic transmission 2000 is controlled such that first gear is implemented.

When 2 range is selected as the shift range of automatic transmission 2000 based on that shift lever 8004 is in 2 position, automatic transmission 2000 is controlled such that first or second gear depending on the state of the vehicle is implemented.

Referring to Fig. 2, engine 1000 will further be described. Engine 1000 is provided with a fuel injection apparatus constituted of a supply pump 114, a common rail 116, and an injector 118. Engine 1000 is also provided with a turbocharger constituted of a compressor 104 and a turbine 122. The air taken into engine 1000 is filtered by an air cleaner 102, and compressed by compressor 104 of the turbocharger. The compressed air undergoes heat exchange between the outside air by an inter-cooler 106 thereby being cooled. The air passes through an intake pipe 108 and an intake manifold 110, and is introduced into the combustion chamber. Into the combustion chamber, fuel being pressurized by supply pump 114 and stored in common rail 116 is injected by injector 118. In the combustion chamber, the air-fuel mixture burns, whereby engine generates drive force. Common rail 116 is provided with a common rail pressure sensor 138 detecting the pressure in common rail 116. Common rail pressure sensor 138 transmits the detected pressure to ECU 8000. ECU 8000 sets a target pressure of the pressure of the fuel in common rail 116 in accordance with the state of the vehicle, and controls supply pump 114 so that the pressure of the fuel in common rail 116 detected by common rail pressure sensor 138 attains the target pressure. The vehicle state may be, for example, engine rotation speed NE and the gear, although the vehicle state is not specifically limited thereto.

ECU 8000 exerts control to stop fuel injection, when the vehicle is in a driven state. Whether or not the vehicle is in a driven state is determined based on the accelerator pedal position and engine rotation speed, for example. The combusted air-fuel mixture, that is, exhaust gas is lead to an exhaust manifold 120 and passes through turbine 122 of the turbocharger. Thereafter, it is purified by a catalyst 124 and discharged to the outside of the vehicle.

Part of the exhaust gas is recirculated via an EGR (Exhaust Gas Recirculation) pipe 126 coupled to exhaust manifold 120. The exhaust gas flowing through EGR pipe 126 passes through an oxidation catalyst 128 and undergoes heat exchange between cooling water by an EGR cooler 130 thereby being cooled. The cooled exhaust gas is recirculated to the intake side via an EGR valve 132.

The amount of the recirculated exhaust gas (EGR amount) is adjusted by the opening degree of EGR valve 132. The EGR valve opening degree is controlled by an EGR valve linear solenoid 134. In a normal mode, the EGR valve opening degree is controlled such that EGR valve 132 is further closed, i.e., such that the EGR amount becomes small, as the torque of engine 1000 is higher. Specifically, an EGR valve opening degree detected by using an EGR valve lift sensor 136 is input to ECU 8000 and the EGR valve opening degree is feedback-controlled, such that the concentration of intake air oxygen changing by the EGR attains a target value corresponding to the state (engine rotation speed NE, boost pressure, temperatures of respective parts, load, intake air amount) of engine 1000. It is to be noted that the actuation scheme of EGR valve 132 may be negative-pressure type or motor-type, instead of the scheme employing EGR valve linear solenoid 134. In a vehicle having the above-described configuration, the present invention is characterized in the following: when a shift instruction signal corresponding to an instruction of downshift to automatic transmission 2000 is received while the vehicle is in a driven state, ECU 8000 controls supply pump 114 so that the pressure in common rail 116 increases, and controls injector 118 to increase fuel supplied to engine 1000 during the downshift.

ECU 8000 controls injector 118 to increase fuel after a lapse of a predetermined time from the downshift instruction. The predetermined time is the time period from the downshift instruction until an engagement pressure of a frictional engagement element on the release side is reduced to be not greater than a predetermined pressure.

Fig. 3 is a functional block diagram of ECU 8000 being the control apparatus of the vehicle according to the present embodiment. ECU 8000 includes an input interface (hereinafter referred to as input I/F) 300, an operation processing portion 400, a storage portion 500, and an output interface (hereinafter referred to as output I/F) 600. Input I/F 300 receives an engine rotation speed signal from engine rotation speed sensor 8020, a turbine rotation speed signal from input shaft rotation speed sensor 8022, an output shaft rotation speed signal from output shaft rotation speed sensor 8024, an accelerator pedal position signal from accelerator pedal position sensor 8010, a vehicle speed signal from vehicle speed sensor 8002, a shift manipulation signal (shift instruction signal) from position switch 8006, and a common rail pressure signal from common rail pressure sensor 138, and transmits the same to operation processing portion 400.

Operation processing portion 400 includes a shift determining portion 402, a state determining portion 404, an instruction pressure signal generating portion 406, and a fuel injection control portion 408.

Shift determining portion 402 determines whether or not there is a downshift instruction based on a shift manipulation signal. For example, when there is manipulation of shift lever 8004 corresponding to downshift while in the manual shift mode, shift determining portion 402 determines that there is a downshift instruction. Alternatively, when there is manipulation of selecting the shift position of L position or 2 position while in the automatic shift mode and it is determined that downshift from the current gear is necessary, shift determining portion 402 determines that there is a downshift instruction. Shift determining portion 402 may set a shift determination flag on, for example, when it determines that there is a downshift instruction.

State determining portion 404 determines whether or not the vehicle is in a driven state, based on an engine rotation speed signal and an accelerator pedal position signal. For example, when engine rotation speed NE is not smaller than a predetermined engine rotation speed that is substantially equal to an idle rotation speed and an accelerator pedal position is not greater than a predetermined position that is substantially zero, state determining portion 404 determines that the vehicle is in a driven state. State determining portion 404 may set a state determination flag on, for example, when it determines that the vehicle is in a driven state. When shift determining portion 402 determines that there is a downshift instruction and state determining portion 404 determines that the vehicle is in a driven state, instruction pressure signal generating portion 406 sets a target pressure and generates a common rail instruction pressure signal. Specifically, instruction pressure signal generating portion 406 sets a target pressure based on engine rotation speed NE and an after-downshift gear. Instruction pressure signal generating portion 406 generates a common rail instruction pressure signal based on the set target pressure and the detected pressure in common rail 116. That is, instruction pressure signal generating portion 406 generates the common rail instruction pressure signal such that the detected pressure in common rail 116 achieves the target pressure. Instruction pressure signal generating portion 406 transmits the generated common rail instruction pressure signal via output I/F 600 to supply pump 114.

Instruction pressure signal generating portion 406 may generate the common rail instruction pressure signal, for example when both the shift determination flag and the state determination flag are on, and transmits the same to supply pump 114. After a lapse of a predetermined time from the driver's downshift manipulation, fuel injection control portion 408 generates a fuel injection control signal such that increased fuel is injected, and transmits the generated fuel injection control signal via output I/F 600 to injector 118. Fuel injection control portion 408 may transmit the fuel injection control signal to injector 118, for example after a lapse of a predetermined time from setting-on of the shift determination flag. The predetermined time is at least a time from a start of shifting gears until an engagement pressure of a frictional engagement element on the release side becomes not greater than a predetermined pressure. It may be set corresponding to the after-shift gear.

In the present embodiment, while the description is given referring to shift determining portion 402, state determining portion 404, instruction pressure signal generating portion 406, and fuel injection control portion 408 are all function as software that is realized by a CPU being operation processing portion 400 executing a program stored in storage portion 500, they may be realized by hardware. It is to be noted that such a program is recorded on a recording medium and incorporated in the vehicle.

In storage portion 500, various information, programs, threshold values, maps and the like are stored. As necessary, data is read or stored by operation processing portion 400.

In the following, referring to Fig. 4, a control structure of a program executed by ECU 8000 being a control apparatus for the vehicle according to the present . embodiment will be described.

In step (hereinafter step is referred to as S) 100, ECU 8000 determines whether or not there is a downshift instruction based on driver's manipulation of shift lever 8004. When there is a downshift instruction (YES in SlOO), the processing moves to S 102. Otherwise (NO in SlOO), the processing ends.

In S 102, ECU 8000 determines that whether or not the vehicle is in a driven state. When the vehicle is in a driven state (YES in S 102), the processing moves to S104. Otherwise (NO in S102), the processing ends. In S 104, ECU 8000 outputs to supply pump 114 a control signal corresponding to a common rail instruction pressure based on a target pressure and a detected pressure in common rail 116.

In S 106, ECU 8000 determines whether or not a predetermined time has elapsed from the downshift instruction. When a predetermined time has elapsed from the downshift instruction (YES in S106), the processing moves to S108. Otherwise (NO in S 106), the processing returns to S 106. In S 108, ECU 8000 executes fuel injection control. An operation of ECU 8000 being the control apparatus for the vehicle according to the present embodiment based on the above-described structure and flowchart will be described referring to Fig. 5.

It is assumed that the accelerator pedal position is substantially zero and a change amount of engine rotation speed NE is not greater than a predetermined value. Here, the vehicle is in a driven state and decelerating by the running resistance. Here, since fuel injection is stopped, the pressure in common rail 116 is low.

At time point T(O), when the driver manipulates shift lever 8004 to downshift the current gear to a gear on low-speed side (YES in SlOO), since the vehicle is in a driven state (YES in S 102), a control signal corresponding to common rail instruction pressure P(O) based on a target pressure and a detected common rail pressure is output to supply pump 114 (S 104). By the output of the control signal corresponding to common rail instruction pressure P(O), as indicated by the solid line in Fig. 5, the common rail instruction pressure starts to increase stepwise to P(O), at the time point of T(O). Along with the increase in the common rail instruction pressure, the actual pressure in common rail 116 increases so as to reach P(O).

At time point T(I), after a lapse of a predetermined time from the time point (time point T(O)) of the driver's downshift manipulation (YES in S 106), fuel injection control is executed (S 108). By the injection of fuel, output torque of engine 1000 increases and engine rotation speed NE starts to increase. When both the control of fuel injection and the output of common rail instruction pressure are simultaneously executed, as indicated by the solid line in Fig. 5, at time point T(I), the common rail instruction pressure is output. Therefore, when fuel injection is performed at time point T(2), the actual pressure in common rail 116 is not fully increased as compared to the solid line in Fig. 5. Thus, the fuel injection amount becomes insufficient.

Accordingly, by outputting the common rail instruction pressure together with the downshift instruction, the initial fuel injection amount is increased as compared to the case where the fuel injection control and the output of common rail instruction pressure are simultaneously executed. Therefore, the degree of increase in engine rotation speed NE during shifting becomes great. Therefore, the turbine rotation speed is allowed to quickly reach the synchronous rotation speed, whereby shifting time can be shortened. At time point T(2), the injection of fuel is stopped by the increase in engine rotation speed NE. At time point T(3), the common rail instruction pressure becomes low corresponding to the fuel injection being stopped. At time point T(4), the common rail pressure becomes low corresponding to the common rail instruction pressure becoming low. At time point T(5), when turbine rotation speed NT reaches the synchronous rotation speed as, for example, the difference between turbine rotation speed NT and the synchronous rotation speed of the after-shift gear becomes not greater than a predetermined value, the shifting ends.

As described above, according to the control apparatus for the vehicle according to the present embodiment, the pressure in the common rail can be increased before fuel is supplied to the engine. Therefore, a response delay of the pressure in the common rail at the time point of supplying fuel in an increased amount can be solved. Thus, insufficiency of the injection amount at the initial stage of fuel injection can be solved, and fuel corresponding to the state of the vehicle can be supplied to the engine. As a result, it becomes possible to quickly increase the engine output torque, thereby shortening the shifting time. Accordingly, it becomes possible to provide the control apparatus and method for the vehicle that execute fuel increase control without a response delay, when the driver manipulates the automatic transmission thereby instructing downshift. Furthermore, by increasing fuel and supplying the same to the engine after a lapse of a predetermined time from the downshift instruction, the output of the engine can be increased at the time point where the shift state of the automatic transmission becomes substantially neutral. Accordingly, while suppressing the sudden acceleration feeling of the vehicle caused by the output of the engine being transmitted to the driving wheels of the vehicle, the rotation speed of the input side of the automatic transmission can be increased so that shifting quickly proceeds.

It should be understood that the embodiment disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any changes within the meaning and scope equivalent to the terms of the claims.

Claims

1. A control apparatus for a vehicle equipped with an internal combustion engine (1000) and an automatic transmission (2000), said internal combustion engine (1000) having a fuel injection apparatus including: a pressure accumulation chamber (116) storing pressurized fuel; a fuel pump (114) sending the fuel with pressure to said pressure accumulation chamber (116); and an injector (118) supplying the fuel in said pressure accumulation chamber (116) to said internal combustion engine (1000), said control apparatus comprising: means for receiving a shift instruction signal; pressure control means (406) for controlling said fuel pump (114) so that pressure in said pressure accumulation chamber (116) increases, when the shift instruction signal corresponding to an instruction of downshift to said automatic transmission (2000) is received while said vehicle is in a driven state; and injection control means (408) for controlling said injector (118) to increase the fuel supplied to said internal combustion engine (1000), during said downshift.

2. The control apparatus for the vehicle according to claim 1, further comprising means for detecting the pressure in said pressure accumulation chamber (116), wherein said pressure control means (406) includes setting means for setting a target pressure in said pressure accumulation chamber (116) in accordance with a state of said vehicle, and means for controlling said fuel pump (114) so that the detected pressure attains said target pressure.

3. The control apparatus for the vehicle according to claim 2, further comprising means for detecting a rotation speed of said internal combustion engine (1000), wherein said setting means includes means for setting said target pressure based on the detected rotation speed and a gear after said downshift.

4. The control apparatus for the vehicle according to claim 1, wherein said injection control means (408) includes means for controlling said injector (118) to increase the fuel after a lapse of a predetermined time from said instruction of downshift.

5. The control apparatus for the vehicle according to claim 4, wherein said automatic transmission (2000) is a gear type automatic transmission, in which a first frictional engagement element in a released state is engaged and a second frictional engagement element in an engaged state is released by hydraulic pressure supplied based on an instruction value output to a hydraulic circuit (4000), whereby a gear after downshift is implemented, and said predetermined time is at least a time from a start of shifting gears until an engagement pressure of said second frictional engagement element is reduced to be not greater than a predetermined pressure.

6. The control apparatus for the vehicle according to one of claims 1-5, wherein said internal combustion engine (1000) is a common rail type diesel engine.

7. A control method of a vehicle equipped with an internal combustion engine (1000) and an automatic transmission (2000), said internal combustion engine (1000) having a fuel injection apparatus including: a pressure accumulation chamber (116) storing pressurized fuel; a fuel pump (114) sending the fuel with pressure to said pressure accumulation chamber (116); and an injector (118) supplying the fuel in said pressure accumulation chamber (116) to said internal combustion engine (1000), said control method comprising: a step of receiving a shift instruction signal; a pressure control step of controlling said fuel pump (114) so that pressure in said pressure accumulation chamber (116) increases, when the shift instruction signal corresponding to an instruction of downshift to said automatic transmission (2000) is received while said vehicle is in a driven state; and an injection control step of controlling said injector (118) to increase the fuel supplied to said internal combustion engine (1000), during said downshift.

8. The control method of the vehicle according to claim 7, further comprising a step of detecting the pressure in said pressure accumulation chamber (116), wherein said pressure control step includes a setting step of setting a target pressure in said pressure accumulation chamber (116) in accordance with a state of said vehicle, and a step of controlling said fuel pump (114) so that the detected pressure attains said target pressure.

9. The control method of the vehicle according to claim 8, further comprising a step of detecting a rotation speed of said internal combustion engine (1000), wherein said setting step includes a step of setting said target pressure based on the detected rotation speed and a gear after said downshift.

10. The control method of the vehicle according to claim 7, wherein said injection control step includes a step of controlling said injector (118) to increase the fuel after a lapse of a predetermined time from said instruction of downshift.

11. The control method of the vehicle according to claim 10, wherein said automatic transmission (2000) is a gear type automatic transmission, in which a first frictional engagement element in a released state is engaged and a second frictional engagement element in an engaged state is released by hydraulic pressure supplied based on an instruction value output to a hydraulic circuit (4000), whereby a gear after downshift is implemented, and said predetermined time is at least a time from a start of shifting gears until an engagement pressure of said second frictional engagement element is reduced to be not greater than a predetermined pressure.

12. The control method of the vehicle according to one of claims 7-11, wherein said internal combustion engine (1000) is a common rail type diesel engine.