EP1022452B1 - Dispositif et procédé de commande d'injection de combustible du type à accumulation - Google Patents

Dispositif et procédé de commande d'injection de combustible du type à accumulation Download PDF

Info

Publication number
EP1022452B1
EP1022452B1 EP20000100581 EP00100581A EP1022452B1 EP 1022452 B1 EP1022452 B1 EP 1022452B1 EP 20000100581 EP20000100581 EP 20000100581 EP 00100581 A EP00100581 A EP 00100581A EP 1022452 B1 EP1022452 B1 EP 1022452B1
Authority
EP
European Patent Office
Prior art keywords
fuel
fuel injection
pressure
amount
timing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP20000100581
Other languages
German (de)
English (en)
Other versions
EP1022452A2 (fr
EP1022452A3 (fr
Inventor
Tatsumasa Sugiyama
Yuuichirou Katou
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP1632399A external-priority patent/JP4055279B2/ja
Priority claimed from JP06028299A external-priority patent/JP4280350B2/ja
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Publication of EP1022452A2 publication Critical patent/EP1022452A2/fr
Publication of EP1022452A3 publication Critical patent/EP1022452A3/fr
Application granted granted Critical
Publication of EP1022452B1 publication Critical patent/EP1022452B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0003—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure
    • F02M63/0007—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure using electrically actuated valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0602—Fuel pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0602—Fuel pressure
    • F02D2200/0604—Estimation of fuel pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/12—Timing of calculation, i.e. specific timing aspects when calculation or updating of engine parameter is performed

Definitions

  • the present invention relates to an accumulator fuel injection control apparatus and method for an internal combustion engine and, more particularly, to an accumulator fuel injection control apparatus and method for an internal combustion engine that is capable of improving precision of fuel injection control in a state of transition.
  • a fuel pressure in the accumulator line is first detected as a fuel injection pressure, and a required injection amount is calculated as an operation state of the engine. Then, a command value for determining a valve-open period of the fuel injection valves is set based on the fuel pressure and the required injection amount. By driving the fuel injection valves based on the command value, the fuel injection valves inject fuel of an amount equal to the required injection amount.
  • fuel injection is performed based on a fuel pressure that is higher than the fuel pressure at the time of setting of the command value. Accordingly, the amount of fuel actually injected from the fuel injection valves exceeds the required injection amount. If such a discrepancy between the actual fuel injection amount and the required injection amount becomes too great, problems such as deterioration in exhaust properties and the like arise.
  • the difference between a value of fuel pressure detected last time and a value of fuel pressure detected the second last time is added to the value detected last time during a transitional operation state of the engine, and a fuel injection period (a command value) is set based on the added value and the required fuel injection amount. That is, the change in fuel pressure during a period from detection of a fuel pressure to the start of fuel injection is predicted based on a record of such change, and the predicted value is used in setting a fuel injection period instead of an actual measurement value.
  • the fuel injection period can be set suitably by preliminarily taking into account a change in fuel pressure during a period from detection of a fuel pressure to the start of fuel injection.
  • the fuel injection amount can be controlled with high precision.
  • a predictive value which preliminarily takes into account a change in fuel injection pressure between a timing for actual measurement of fuel injection pressure and a timing for fuel injection by the injectors, is used to calculate a fuel injection amount.
  • the timing for measuring an actual measurement value of fuel injection pressure is advanced, the measurement is actually carried out during a pump force-feed stroke, so that the fuel injection pressure during the pump force-feed stroke is obtained.
  • the fuel injection pressure during the pump force-feed stroke is different from the fuel injection pressure at the time of the start of fuel injection. Therefore, if the timing for measuring an actual measurement value of fuel injection pressure is advanced, the precision in fuel injection control amount decreases.
  • the accumulator fuel injection control apparatus is provided with detection means for detecting a fuel pressure in an accumulator line, estimation means for estimating a pressure of fuel injected into an engine, fuel injection control amount calculation means for calculating a fuel injection control amount based on the detected fuel pressure or on the estimated fuel pressure, and fuel injection means for injecting fuel into the engine based on the calculated fuel injection control amount.
  • the gist of the present invention is that the fuel injection control amount calculation means determines which of the detected fuel pressure and the estimated fuel pressure is to be used, based on a fuel injection timing of the injection means.
  • Fig. 1 schematically shows a structure of an accumulator fuel injection control apparatus for an internal combustion engine according to the present invention.
  • an engine 1 a four-cylinder engine in this case
  • injectors 2 for injecting high-pressure fuel to combustion chambers of respective cylinders are disposed.
  • Fuel injection from the injectors 2 to the engine 1 is controlled by opening and closing injection control electromagnetic valves 3.
  • the injectors 2 are connected to a common rail 4 that is commonly used for the respective cylinders. While the injection control electromagnetic valves 3 are open, fuel in the common rail 4 is injected from the injectors 2 into the combustion chambers of the engine 1.
  • the common rail 4 Because the fuel pressure in the common rail is a fuel injection pressure, the common rail 4 needs to accumulate a suitable fuel pressure corresponding to an operation state. For this reason, a high-pressure pump 7 that is capable of supplying high-pressure fuel is connected to the common rail 4 through a feed line 6 and a check valve 5. The check valve 5 allows fuel to flow only in a direction from the high-pressure pump 7 to the common rail 4.
  • a pressure sensor 14 detects an injection pressure of fuel injected from the injector 2 into the combustion chamber of the engine 1, namely, a fuel pressure (rail pressure) in the common rail.
  • the high-pressure pump 7 force-feeds a required amount of fuel, which has been sucked from a fuel tank 8 through a low-pressure feed pump 9, to the common rail 4 by reciprocating two plungers (not shown) through a cam (not shown) that synchronizes with rotation of the engine 1.
  • This cam has a lift characteristic of two different phases (see Figs. 2 and 3).
  • the high-pressure pump 7 is equipped with two discharge amount control devices 10 corresponding to the two plungers.
  • Each of the discharge amount control devices 10 is equipped with a high-pressure pump valve (not shown) for opening and closing an intake port of the high-pressure pump 7.
  • This high-pressure pump valve adjusts an effective force-feed stroke of the high-pressure pump 7 and controls a discharge amount. By controlling this discharge amount, the pressure in the common rail is determined based on a difference between an amount of fuel discharged from the common rail through fuel injection and an amount of fuel supplied from the high-pressure pump.
  • ECU electronice control unit
  • Detection signals from an engine rotational speed sensor 12 and an accelerator opening degree sensor 13 are inputted to the ECU 11.
  • input signals from the pressure sensor 14 and various sensors for detecting coolant temperature, intake air temperature, intake air pressure and the like are inputted to the ECU 11.
  • the ECU 11 determines an operation state of the engine based on those input signals, performs an arithmetic processing according to a predetermined program, and outputs optimal control signals for the injection control electromagnetic valves 3 and the discharge amount control devices 10.
  • the ECU 11 is equipped with memories (RAM, ROM) for storing detected data, control programs and the like.
  • the ECU 11 is equipped with a fuel injection amount calculating portion 21 and a fuel injection pressure predictive value calculating portion 22, which will be described later.
  • Figs. 2 and 3 are graphs illustrating a relationship between fuel injection timing and timing for measuring an actual measurement value of fuel injection pressure.
  • Fig. 2 shows a case where the actual measurement value is used to calculate a fuel injection amount.
  • Fig. 3 shows a case where a predictive value is used to calculate a fuel injection amount.
  • the rail pressure rises due to force-feeding of fuel by the pump in a range indicated by hatched zones in Figs. 2 and 3, after having fallen due to a decrease in amount of fuel in the rail resulting from fuel injection.
  • the pressure sensor 14 detects a pressure (a rail pressure P2 in Fig. 3) of fuel injected into the combustion chambers of the engine 1 from the injectors 2 at a first timing t1.
  • the fuel injection amount calculating portion 21 calculates a second timing t2 for start of fuel injection by the injectors 2 from an operation state of the engine. In this case, there are two fuel injection pulses as pilot injection and main injection are taken into account.
  • the fuel injection amount calculating portion 21 compares a first time T1 corresponding to a difference between the first timing t1 and the second timing t2 with a second time T2 required for the arithmetic processing of a fuel injection amount based on an actual measurement value of fuel injection pressure detected at the first timing t1.
  • the fuel injection amount calculating portion 21 calculates a fuel injection amount at the second timing t2, using a result of the arithmetic processing of the actual measurement value of fuel injection pressure detected at the first timing t1.
  • the fuel injection pressure predictive value calculating portion 22 calculates, at a timing t exp , a predictive value of fuel injection pressure at the first timing t1 based on an actual measurement value of fuel injection pressure in a preceding cycle (a rail pressure P1 in Fig. 3).
  • the fuel injection amount calculating portion 21 calculates a fuel injection amount at the second timing t2, using the predictive value calculated by the fuel injection pressure predictive value calculating portion 22.
  • the result of calculation of injection control at the timing t exp is used to calculate a fuel injection amount during pilot injection.
  • the calculation of injection control is performed also at the first timing t1.
  • the result of calculation of injection control at the first timing t1 is used to calculate a fuel injection amount during main injection.
  • a timing when the actual measurement value can be utilized is reached.
  • the actual measurement value of fuel injection pressure is used.
  • the fuel injection amount calculating portion 21 determines which of the actual measurement value and the predictive value of fuel injection pressure is to be used to calculate a fuel injection amount, based on the first time T1 between the first timing t1 and the second timing t2 and on the second time T2 required for the arithmetic processing of a fuel injection amount derived from the actual measurement value of fuel injection pressure measured at the first timing t1.
  • the second timing t2 is advanced with respect to a timing (t1+T2) where the arithmetic processing of fuel injection amount based on the actual measurement value of fuel injection pressure is terminated. Therefore, the actual measurement value cannot be used.
  • Fig. 4 is a flowchart for calculating fuel injection pressure and performing an arithmetic processing of fuel injection amount, in a fuel injection control routine that is executed every time a crank shaft rotates by a predetermined angle.
  • the fuel injection amount calculating portion 21 determines whether or not a timing t120 for calculating a second timing t2 where the injectors 2 inject fuel has been reached (S41). If it is determined that the timing t120 has been reached, the process proceeds to S42. If it is determined that the timing t120 has not been reached, the process proceeds to S47.
  • the fuel injection amount calculating portion 21 calculates a second timing t2 where the injectors 2 inject fuel, based on an operational condition of the engine and the like. Depending on the operational condition of the engine, the fuel injection amount calculating portion 21 also determines whether fuel injection is to be carried out once or twice (so-called pilot injection).
  • the fuel injection amount calculating portion 21 determines whether or not a timing (t1+T2) after the lapse of the time T2 required for calculation of a fuel injection amount from the first timing t1 when an actual measurement value of fuel injection pressure is obtained is advanced with respect to the second timing t2, which is a fuel injection timing (S43).
  • a timing t1+T2
  • T2 time required for calculation of a fuel injection amount from the first timing t1 when an actual measurement value of fuel injection pressure is obtained is advanced with respect to the second timing t2, which is a fuel injection timing (S43).
  • the fuel injection timing and a time required for calculation of fuel injection amount every time and compare them if the time required for calculation of fuel injection amount is substantially constant regardless of an operation state of the engine, the determination can be made on the basis of a difference between a fuel injection timing and a timing of actual measurement of fuel injection pressure.
  • the timing of actual measurement of fuel injection pressure is also constant regardless of an operation state of the engine, the determination can be made only on the basis of what
  • the process proceeds to S44 where the flag is set on.
  • the fuel injection amount calculating portion 21 calculates a fuel injection amount at the second timing t2 using a predictive value of fuel injection pressure calculated by the fuel injection pressure predictive value calculating portion 22 (S46).
  • the step S46 corresponds to an operation performed at the timing t exp shown in Fig. 3. A concrete method of calculating a predictive value in this step will be described later with reference to Fig. 5.
  • the fuel injection amount calculating portion 21 determines whether or not a first timing when the pressure sensor 14 detects an injection pressure of fuel injected into the combustion chambers of the engine 1 from the injectors 2 has been reached (S47).
  • the pressure sensor 14 detects a fuel injection pressure of fuel injected into the combustion chambers of the engine 1 from the injectors 2 (S48). If not, the process skips the step of measuring a fuel injection pressure and the step of calculating a fuel injection amount based on an actual measurement value of fuel injection pressure, and proceeds to a step of performing fuel injection (not shown) or the like in the present routine.
  • the detection of fuel injection pressure in S48 includes performing AID conversion of an analog output of the sensor 14 and retrieving the converted output into the ECU 11.
  • the fuel injection amount calculating portion 21 determines whether or not the flag has been set off (S49). If it is determined that the flag has been set off, the fuel injection amount calculating portion 21 calculates a fuel injection amount using a result of the arithmetic processing of the actual measurement value of fuel injection pressure calculated in S48 (S50).
  • Fig. 5 is a flowchart showing a process of calculating a predictive value of fuel injection pressure used in S46.
  • the fuel injection pressure predictive value calculating portion 22 calculates a pump force-feed amount P p , of the high-pressure pump 7 based on a fuel intake amount, a fuel temperature, an engine rotational speed and a fuel injection pressure P pre in a preceding cycle (S51).
  • the fuel injection pressure predictive value calculating portion 22 calculates an injector leakage amount Pr based on a period of supply of electricity, a fuel temperature, an engine rotational speed and a rail pressure P pre in a preceding cycle (S52).
  • the injector leakage amount refers to an amount of fuel that is discharged (mainly fuel injection) through the injectors from the common rail 4.
  • the fuel injection pressure predictive value calculating portion 22 calculates a volume elasticity coefficient K p of the fuel in the common rail 4 based on a fuel temperature and a rail pressure P pre in a preceding cycle (S53).
  • the fuel injection amount calculating portion 21 calculates a fuel injection amount using an actual measurement value of fuel injection pressure when the first time T1 is longer than the second time T2, and calculates a fuel injection amount using a predictive value of fuel injection pressure when the first time T1 is equal to or shorter than the second time T2. Accordingly, even if the timing for measuring a fuel injection pressure is not changed, the fuel injection amount can be calculated using an actual measurement value of fuel injection pressure to a possible extent. Thus, the frequency with which the control is performed using an indefinite predictive value at the time of transition is reduced. Consequently, the precision of fuel injection control is enhanced, and it is possible to make use of a predictive value corresponding to the fuel injection timing.
  • the timing for fuel injection is directly compared with the timing for termination of control, the frequency with which the actual measurement value of fuel injection pressure can be used is enhanced.
  • it may be determined based on an engine rotational speed which of an actual measurement value and a predictive value is to be used to calculate a fuel injection amount.
  • the time for a crank angle during high-speed rotation of the engine is shorter than the time for that crank angle during low-speed rotation of the engine.
  • the timing (t1) for actual measurement of fuel injection pressure and the timing (t2) for fuel injection are set as crank angles
  • the time (T2) for calculation of fuel injection amount is determined as a time instead of a crank angle.
  • the time (T1) from the timing (t1) for detection of fuel pressure to the timing (t2) for fuel injection may differ depending on an engine rotational speed.
  • the relationship in length between T1 and T2 changes.
  • the step of determining whether or not the engine rotational speed is lower than a predetermined value N1 may be carried out instead of S43 of the flowchart shown in Fig. 4.
  • the process proceeds to S45 where the flag is set off. If it is determined that the engine rotational speed is equal to or higher than N1[rpm], the process proceeds to S45 where the fuel injection amount calculating portion 21 sets the flag on.
  • the rotational speed N1 as mentioned herein can be selected arbitrarily. It is preferable to select a rotational speed across which the frequency, with which the fuel injection timing when the value obtained by time-converting a difference in crank angle between the timing for measuring fuel pressure (tl in Figs. 2, 3) and the timing for fuel injection by a rotational speed at that time exceeds the time required for calculation of fuel injection amount is set, changes.
  • the actual measurement value and the predictive value are distinguished from each other only by determining whether or not a detection signal from the engine rotational speed sensor 12 is at a level lower than a predetermined rotational speed. Therefore, the arithmetic load applied to the ECU can be reduced.
  • the present embodiment makes it possible to provide an accumulator fuel injection control apparatus which exhibits a good precision of fuel injection control at the time of transition.
  • Fig. 6 schematically shows an engine 110 and a high-pressure fuel injection system thereof.
  • This high-pressure fuel injection system is equipped with injectors 112 provided so as to correspond to respective cylinders #1 through #4 of the engine 110, a common rail 120 to which the respective injectors 112 are connected, a fuel pump 130 for force-feeding the fuel in a fuel tank 114 to the common rail 120, and an ECU 160.
  • a relief valve 122 is attached to the common rail 120.
  • the relief valve 122 is connected to the fuel tank 114 through a relief passage 121. If the fuel pressure (rail pressure) inside the common rail exceeds a predetermined upper limit value, the relief valve 122 is opened so as to reduce the pressure.
  • the injectors 112 which are electromagnetic valves that are opened and closed by the ECU 160, inject the fuel supplied from the common rail 120 into combustion chambers (not shown) of the respective cylinders #1 through #4.
  • the respective injectors 112 are also connected to the fuel tank 114 through the relief passage 21. Even when all the injectors 112 are closed, part- of the fuel supplied from the common rail 120 to the respective injectors 112 constantly leaks into the injectors 112. The fuel that has thus leaked is returned to the fuel tank 114 through the relief passage 121.
  • the ECU 160 performs control relating to force-feeding of fuel by the fuel pump 130 and fuel injection by the injectors 112.
  • the ECU 160 is composed of a memory 164 for storing various control programs, functional data and the like, a CPU 162 for performing various arithmetic processings, and the like.
  • various sensors for detecting an operation state of the engine 110 and a state of fuel in the common rail 120 and the like are connected to the ECU 160. Detection signals from those sensors are inputted to the ECU 160.
  • a rotational speed sensor 165 is provided in the vicinity of a crank shaft (not shown) of the engine 110, and a cylinder discriminating sensor 66 is provided in the vicinity of a cam shaft (not shown). Based on detection signals inputted from the respective sensors 165, 166, the ECU 160 calculates a rotational speed of the crank shaft (an engine rotational speed NE) and a rotational angle of the crank shaft (a crank angle CA).
  • an accelerator sensor 167 is provided in the vicinity of an accelerator pedal (not shown) and detects a detection signal corresponding to a depression amount of the accelerator pedal (an accelerator opening degree ACCP).
  • the common rail 120 is provided with a fuel pressure sensor 168, which outputs a detection signal corresponding to a fuel pressure (an actual fuel pressure PCR).
  • a fuel temperature sensor 169 is provided in the vicinity of a discharge port 38 of the fuel pump 130. The fuel temperature sensor 169 outputs a detection signal corresponding to a temperature of fuel (a fuel temperature THF).
  • the ECU 160 detects an accelerator opening degree ACCP, an actual fuel pressure PCR and a fuel temperature THF based on detection signals from the respective sensors 167 through 169.
  • the fuel pump 130 is equipped with a drive shaft 140 rotationally driven by the crank shaft of the engine 110, a feed pump 131 operating based on rotation of the drive shaft 140, a pair of supply pumps driven by an annular cam 142 formed on the drive shaft 140 (a first supply pump 150a and a second supply pump 150b), and the like.
  • the feed pump 131 sucks fuel in the fuel tank 114 from an intake port 134 through an intake passage 124, and supplies the fuel to the first supply pump 150a and the second supply pump 150b at a predetermined feed pressure. Out of the fuel that has been sucked from the intake port 134, the surplus fuel that is supplied to neither the first supply pump 150a nor the second supply pump 150b is returned to the fuel tank 114 from a relief port 136 through the relief passage 121.
  • Both the first supply pump 150a and the second supply pump 150b are pumps of an inner cam type. These pumps pressurize the fuel supplied from the feed pump 131 to a higher pressure (e.g. 25 to 180MPa) based on reciprocating movements of a plunger (not shown), and force-feed the pressurized fuel to the common rail 120 from a discharge port 138 through a discharge passage 123.
  • the supply pumps 150a, 150b perform such a force-feed operation of fuel alternately and intermittently.
  • the fuel pump 130 is provided with first and second adjusting valves 170a, 170b for adjusting amounts of fuel force-fed from the supply pumps 150a, 150b respectively. Both the adjusting valves 170a, 170b are designed as electromagnetic valves that are driven by the ECU 160 to be opened and closed.
  • Fig. 7 is a timing chart showing timings for sucking fuel through and force-feeding fuel from the respective supply pumps 150a, 150b, a pattern of change in fuel injection pressure resulting from fuel leakage, and the like.
  • the respective supply pumps 150a, 150b alternately suck fuel into the fuel pump 30 with phases in crank angle CA (CA: Crank Angle) being offset from each other by 180°CA.
  • CA crank Angle
  • the respective supply pumps 150a, 150b alternately force-feed fuel from the fuel pump 130 with phases being offset from each other by 180°CA.
  • the first adjusting valve 70a is opened during an intake stroke of the first supply pump 150a so as to start sucking fuel, and is closed at a predetermined timing (crank angle CA) so as to stop sucking fuel. All the fuel that has been thus sucked is pressurized in a force-feed stroke which follows the intake stroke, and is force-fed from the first supply pump 150a to the common rail 120.
  • the amount of fuel force-fed from the first supply pump 150a can be adjusted by changing a timing for closing the first adjusting valve 170a.
  • crank angle CA for closing a second adjusting valve 70b
  • the amount of fuel force-fed from the second supply pump 150b can be changed.
  • the timing for starting force-feeding fuel from the second supply pump 50b is advanced or retarded by a crank angle equal to the amount of retardation or advancement of a closed-valve period thereof.
  • the timings for starting sucking fuel through and finishing force-feeding fuel from the respective supply pumps 150a, 150b are set to constant timings (crank angles CA).
  • the timings for starting force-feeding fuel from the respective supply pumps 150a, 150b can be calculated based on open-valve periods of the respective adjusting valves 170a, 170b.
  • the amounts of fuel force-fed from the respective supply pumps 150a, 150b per unit crank angle CA (hereinafter referred to as "fuel force-feed rate KQPUMP”) are equal to each other and always constant regardless of the timings for starting force-feeding fuel. Accordingly, the total amounts of fuel force-fed from the respective supply pumps 150a, 150b during the force-feed periods can be calculated by multiplying the force-feed periods by the fuel force-feed rate KQPUMP.
  • the ECU 60 sets a target pressure of fuel injection pressure based on an operation state of the engine. Based on a difference between the target pressure and an actual fuel pressure PCR detected by a fuel pressure sensor 68, the ECU 60 controls the aforementioned adjusting valves 170a, 170b such that the fuel injection pressure becomes equal to the target pressure.
  • the fuel injection pressure is raised by retarding timings for opening the respective adjusting valves 170a, 170b and increasing an amount of fuel force-fed.
  • the fuel injection pressure is prevented from rising by advancing timings for closing the respective adjusting valves 170a, 170b and reducing an amount of fuel force-fed, and the fuel injection pressure is reduced through fuel injection.
  • the fuel injection pressure is adjusted to a pressure suited for an operation state of the engine.
  • the ECU 160 calculates a required injection amount based on an operation state of the engine, and calculates a fuel injection period (an open-valve period) based on the required injection amount and the fuel injection pressure (the actual fuel pressure PCR). Based on the thus-calculated fuel injection period, the injectors 12 are driven by the ECU 60 to be opened and closed.
  • the value of fuel injection pressure when calculating a fuel injection period namely, the actual fuel pressure PCR detected by the fuel pressure sensor 168 does not always coincide with the value of fuel injection pressure at the time of start of fuel injection.
  • the fuel in the common rail 120 constantly leaks out to the fuel tank 114 through the injectors 112.
  • the fuel injection pressure PCRINJ at the time of start of fuel injection may become lower than the actual fuel pressure PCR due to the leakage of fuel.
  • the fuel injection pressure PCRINJ at the time of start of fuel injection may become higher than the actual fuel pressure PCR due to the force-feeding of fuel.
  • a change in fuel injection pressure from detection of the actual fuel pressure PCR to the start of fuel injection is estimated, and the change in fuel injection pressure is reflected on calculation of a fuel injection period.
  • Figs. 9 and 10 are flowcharts showing processes of calculating a fuel injection period.
  • the ECU 160 carries out a series of processings shown in those respective flowcharts as an interrupt handling at intervals of a predetermined crank angle (180°CA).
  • step 100 the ECU 60 detects an actual fuel pressure PCR.
  • the timing when the actual fuel pressure PCR is detected namely, the timing when the present routine interrupts is set to a timing when the respective supply pumps 150a, 150b are switched from an intake stroke to a force-feed stroke (a timing when the crank angle CA reaches angles CA0, CA1, CA2 and CA3 shown in the respective drawings).
  • a required injection amount QFIN is calculated based on an accelerator opening degree ACCP, an engine rotational speed NE and the like.
  • a basic injection period TQFINB is calculated based on the required injection amount QFIN and the actual fuel pressure PCR.
  • the required injection amount QFIN and the actual fuel pressure PCR in relation to the basic injection period TQFINB are calculated preliminarily through experiments and the like and stored into the memory 164 of the ECU 160 as functional data for calculating the basic injection period TQFINB.
  • Fig. 11 shows the functional data in the form of a functional map.
  • the basic injection period TQFINB is calculated as a period that becomes longer in proportion to an increase in required injection amount QFINB and a decrease in actual fuel pressure PCR.
  • the pressure change amount DPCR is an amount of change in fuel pressure resulting from force-feeding of fuel or leakage of fuel during a period from detection of the actual fuel pressure PCR (CA0 through CA3 in Figs. 7 and 8) to the start of fuel injection by the injectors 112 (crank angle interval: see (a) in Fig. 7 and (a) in Fig. 8)(the period will be referred to hereinafter as a "pressure change estimation period APCR").
  • Fig. 10 is a flowchart showing in detail a process of calculating a pressure change amount DPCR.
  • the ECU 160 calculates a force-feed period APUMP.
  • the force-feed period APUMP (see (a) in Fig. 8) is a period (crank angle interval) where fuel is force-fed during the pressure change estimation period APCR.
  • the ECU 160 calculates a force-feed starting period of the fuel pump 130 based on timings for closing the respective adjusting valves 170a, 170b as set during an intake stroke prior to the present start of force-feeding of fuel. For example, if the present timing for interruption coincides with a timing CA1 shown in Fig. 8, the force-feed starting period is calculated based on the valve-closing periods that are set during a period from CA0 to CA1. Likewise, if the timing for interruption coincides with a timing CA2, the force-feed starting period is calculated based on the valve-closing periods that are set during a period from CA1 to CA2.
  • the ECU 160 compares the force-feed starting timing with a fuel injection starting timing that is separately calculated. If the force-feed starting timing is retarded with respect to the fuel injection starting timing, namely, unless force-feeding of fuel is carried out prior to the start of fuel injection, the force-feed period APUMP is calculated as zero. On the other hand, if the force-feed starting timing is advanced with respect to the fuel injection starting period, namely, if force-feeding of fuel is started prior to the start of fuel injection, the period between the fuel injection starting timing and the force-feed starting timing is calculated as the force-feed period APUMP.
  • the ECU 160 calculates in step 404 a fuel force-feeding amount QPUMP during the pressure change estimation period APCR according to a calculation formula (I) shown below.
  • QPUMP APUMP ⁇ KQPUMP
  • the ECU 160 calculates a fuel leakage period TLEAK.
  • the fuel leakage period TLEAK is obtained by converting the pressure change estimation period APCR, which is expressed as a unit of crank angle, into a time.
  • the ECU 160 calculates the fuel leakage period TLEAK according to a calculation formula (2) shown below.
  • TLEAK K ⁇ APCR/NE
  • a fuel leakage amount QLEAK during the pressure change estimation period APCR is calculated based on the fuel leakage period TLEAK, the actual fuel pressure PCR and the fuel temperature THF.
  • the fuel leakage amount QLEAK tends to increase in proportion to an increase in fuel leakage period TLEAK, an increase in actual fuel pressure PCR and an increase in fuel temperature THF.
  • the fuel leakage period TLEAK, the actual fuel pressure PCR and the fuel temperature THF in relation to the fuel leakage amount QLEAK are preliminarily calculated through experiments and the like and stored into the memory 164 of the ECU 160 as functional data for calculating the fuel leakage amount QLEAK.
  • a volume elasticity coefficient E of fuel is calculated based on the actual fuel pressure PCR and the fuel temperature THF.
  • the volume elasticity coefficient E tends to increase in proportion to an increase in actual fuel pressure PCR and a decrease in fuel temperature THF.
  • the actual fuel pressure PCR and the fuel temperature THF in relation to the volume elasticity coefficient E are preliminarily calculated through experiments and the like and stored into the memory 164 of the ECU 160 as functional data.
  • the ECU 60 calculates in step 412 a pressure change amount DPCR according to a calculation formula (3) shown below.
  • DPCR E ⁇ (QPUMP-QLEAK)/VCR
  • the pressure change amount DPCR is calculated as a positive value.
  • the pressure change amount DPCR is calculated as a negative value.
  • the ECU 160 shifts the processing to step 500 shown in Fig. 9 and calculates a sensitivity coefficient TQPCR based on the required injection amount QFIN and the actual fuel pressure PCR.
  • the sensitivity coefficient TQPCR is obtained by converting a fuel injection amount deviating from a unitary change amount at the time of such a change in fuel injection pressure (e.g. 1 MPa) into a deviation amount of fuel injection period.
  • the sensitivity coefficient TQPCR and the required injection amount QFIN in relation to the actual fuel pressure PCR are preliminarily calculated through experiments and the like and stored into the memory 164 of the ECU 160 as functional data for calculating the sensitivity coefficient TQPCR.
  • Fig. 12 shows the functional data in the form of a functional map.
  • the sensitivity coefficient TQPCR is calculated as a value that becomes greater in proportion to an increase in required injection amount QFIN and a decrease in actual fuel pressure PCR.
  • step 600 the ECU 160 calculates an injection period correction value TQFINH according to a calculation formula (4) shown below.
  • TQFINH TQPCR ⁇ DPCR
  • the injection period correction value TQFINH is a value for correcting the basic injection period TQFINB so as to compensate for a discrepancy between the actual fuel injection amount and the required injection amount QFIN resulting from the above-mentioned change in fuel injection pressure.
  • step 700 the ECU 60 calculates a final injection period TQFIN according to a calculation formula (5) shown below.
  • TQFIN TQFINB ⁇ TQFINH
  • the ECU 160 After having thus calculated the final injection period TQFIN, the ECU 160 temporarily terminates the present routine.
  • the ECU 160 then produces a drive signal for the injectors 112 based on the final injection period TQFIN and outputs the signal to the injectors 112 at a timing when the crank angle CA coincides with the fuel injection starting timing.
  • the injectors 112 inject fuel of an amount equal to the required injection amount QFIN.
  • the pressure change amount DPCR during the pressure change estimation period APCR is estimated based on the fuel force-feed amount QPUMP and the fuel leakage amount QLEAK.
  • the basic injection period TQFINB which is corrected by the injection period correction value TQFINH based on the pressure change amount DPCR, is set as the final injection period TQFIN.
  • the change amount (the pressure change amount DPCR) can be estimated precisely based on the fuel force-feed amount QPUMP and the fuel leakage amount QLEAK.
  • the final injection period TQFIN can be set with extremely high precision as a value suited for preventing the actual fuel injection amount from deviating from the required injection amount QFIN based on the pressure change amount DPCR.
  • the fuel injection control can be performed with extremely high precision.
  • both the rise in fuel injection pressure resulting from force-feeding of fuel and the fall in fuel injection pressure resulting from leakage of fuel can be reflected on estimation of the pressure change amount DPCR. Accordingly, it is possible to inhibit the actual fuel injection amount from becoming greater or smaller than the required injection amount QFIN due to such a rise or fall in fuel injection pressure.
  • a third embodiment of the present invention will now be described focusing on a difference between the second and third embodiments. The construction similar to that of the second embodiment will not be described.
  • the process of calculating the final injection period TQFIN is different from that of the second embodiment.
  • the ECU 160 calculates in step 400 a pressure change amount DPCR. Then in step 610, the ECU 160 makes a correction by adding the pressure change amount DPCR to an actual fuel pressure PCR and sets a thus-corrected value as a new actual fuel pressure PCR.
  • step 710 as in the processing of step 300 shown in Fig. 9, the ECU 160 calculates a final injection period TQFIN based on the renewed actual fuel pressure PCR and the required injection amount QFIN, by referring to the functional data shown in Fig. 11. After having thus calculated the final injection period TQFIN, the ECU 160 temporarily terminates the processings of this routine.
  • the actual fuel pressure has only to be corrected based on the pressure change amount DPCR prior to calculation of the final injection period TQFIN.
  • the pressure change amount DPCR is estimated based on both the fuel-force-feed amount QPUMP and the fuel leakage amount QLEAK.
  • the pressure change amount DPCR can also be estimated based only on the fuel force-feed amount QPUMP or only on the fuel leakage amount QLEAK.
  • a fourth embodiment of the present invention will now be described focusing on a difference between the second and fourth embodiments.
  • a fuel injection control apparatus is applied to the engine 110 capable of carrying out pilot injection.
  • this pilot injection is intended to inhibit an abrupt rise in combustion pressure by preliminarily injecting a small amount of fuel prior to main injection and to thereby reduce the level of combustion noise.
  • the injection period at the time of main injection (the main injection period TQMAIN) is corrected to an appropriate period based on the amount of decrease in pressure.
  • the timings for opening the respective adjusting valves 170a, 170b are preliminarily set such that force-feeding of fuel by the fuel pump 130 is always started after termination of main injection (see Fig. 16). Therefore, there is no chance that force-feeding of fuel might be carried out during a period from detection of the actual fuel pressure PCR to termination of main injection, or that the fuel injection pressure might change because of force-feeding of fuel.
  • Figs. 14 and 15 are flowcharts showing processes of calculating a main injection period TQMAIN and a pilot injection period TQPLT.
  • Fig. 16 is a timing chart showing timings for sucking fuel into and force-feeding fuel from the respective supply pumps 150a, 150b and a pattern of change in fuel injection pressure caused by pilot injection, main injection and the like.
  • the ECU 60 carries out a series of processings in the respective flowcharts shown in Figs. 14 and 15 as an interrupt handling at intervals of a predetermined crank angle (180 °CA).
  • a predetermined crank angle 180 °CA
  • the timing for interruption of the present routine is set to a timing when the respective supply pumps 50a, 50b are switched from an intake stroke to a force-feed stroke (a timing when the crank angle CA reaches angles CA0, CA1, CA2 and CA3 shown in Fig. 16).
  • the ECU 60 detects an actual fuel pressure PCR in steps 100, 200 shown in Fig. 14, and further calculates a required injection amount QFIN based on an accelerator opening degree ACCP, an engine rotational speed and the like.
  • step 320 the ECU 60 calculates a pilot injection amount QPLT based on the engine rotational speed NE and the required injection amount QFIN.
  • the pilot injection amount QPLT in relation to the engine rotational speed NE and the required injection amount QFIN is preliminarily calculated through experiments and the like so as to best suit an operation state of the engine in consideration of combustion noise, a concentration of exhaust gas and the like, and is stored into the memory 64 as functional data for calculating a pilot injection amount QPLT.
  • a main injection amount QMAIN is calculated according to a calculation formula (6) shown below.
  • QMAIN QFIN - QPLT
  • the ECU 60 calculates in step 450 an amount of change in fuel injection pressure (a pressure change amount DPCRPLT) during a period from detection of the actual fuel pressure PCR to the start of pilot injection (a pressure change estimation period APCRPLT: see Fig. 16) and an amount of change in fuel injection pressure (a pressure change amount DPCRMAIN) during a period from detection of the actual fuel pressure PCR to the start of main injection (a pressure change estimation period APCRMAIN: see Fig. 16).
  • a pressure change amount DPCRPLT an amount of change in fuel injection pressure during a period from detection of the actual fuel pressure PCR to the start of pilot injection
  • a pressure change estimation period APCRMAIN an amount of change in fuel injection pressure during a period from detection of the actual fuel pressure PCR to the start of main injection
  • Fig. 15 is a flowchart showing a process of calculating the respective pressure change amounts DPCRPLT, DPCRMAIN in detail.
  • step 452 the ECU 160 converts the respective pressure change estimation periods APCRPLT, APCRMAIN into times based on the engine rotational speed NE, and sets the converted values as a fuel leakage period TLEAKPLT from detection of the actual fuel pressure PCR to the start of pilot injection and a fuel leakage period TLEAKMAIN from detection of the actual fuel pressure PCR to the start of main injection respectively.
  • the ECU 160 calculates in step 454 an amount of leakage of fuel (a fuel leakage amount QLEAKPLT) from detection of the actual fuel pressure PCR to the start of pilot injection and an amount of leakage of fuel (a fuel leakage amount QLEAKMAIN) from detection ofthe actual fuel pressure PCR to the start of main injection, based on the respective fuel leakage periods TLEAKPLT, TLEAKMAIN, the actual fuel pressure PCR and the fuel temperature THF. Furthermore, as in the processing in step 410 shown in Fig. 10, the ECU 160 calculates in step 456 a volume elasticity coefficient E based on the actual fuel pressure PCR and the fuel temperature THF.
  • a fuel leakage amount QLEAKPLT an amount of leakage of fuel
  • QLEAKMAIN an amount of leakage of fuel
  • step 458 the ECU 60 calculates the respective pressure change amounts DPCRPLT, DPCRMAIN according to calculation formulas (7) and (8) shown below.
  • DPCRPLT QLEAKPLT/VCR
  • DPCRMAIN E ⁇ (QPLT+QLEAKMAIN)/VCR
  • the pilot injection amount QPLT is also reflected on calculation of the pressure change amount DPCRMAIN from detection ofthe actual fuel pressure PCR to the start of main injection. This is because in performing pilot injection, main injection is performed at a fuel injection pressure lower than that of the pilot injection.
  • step 620 the ECU 60 calculates a fuel injection pressure at the time of the start of pilot injection (hereinafter referred to as "a pilot injection fuel pressure") PCRPLT and a fuel injection pressure at the time of the start of main injection (hereinafter referred to as "a main injection fuel pressure”) PCRMAIN according to calculation formulas (9) and (10) shown below respectively.
  • a pilot injection fuel pressure PCR - DPCRPLT
  • a main injection fuel pressure main injection fuel pressure
  • both the pilot injection fuel pressure PCRPLT and the main injection fuel pressure PCRMAIN are obtained by correcting the actual fuel pressure PCR based on the respective pressure change amounts DPCRPLT and DPCRMAIN respectively.
  • step 720 as in the processing of step 710 shown in Fig. 13, the ECU 60 calculates a pilot injection period TQPLT and a main injection period TQMAIN based on the respective fuel pressures PCRPLT, PCRMAIN, the pilot injection amount QPLT and the main injection amount QMAIN, by referring to the functional data shown in Fig. 11.
  • the respective injection periods TQPLT, TQMAIN are corrected substantially based on the aforementioned respective fuel pressures PCRPLT, PCRMAIN.
  • the ECU 60 After having thus calculated the respective injection periods TQPLT, TQMAIN, the ECU 60 temporarily terminates the processings of the present routine.
  • the pilot injection period TQPLT and the main injection period TQMAIN are corrected based on changes in fuel injection pressure from detection of the actual fuel pressure PCR to the start of pilot injection or main injection (the pressure change amounts DPCRPLT, DPCRMAIN).
  • the respective injection periods TQPLT, TQMAIN can be set with extremely high precision as values suited for preventing the actual fuel injection amounts during pilot injection and main injection from deviating from the pilot injection amount QPLT and the main injection amount QMAIN respectively. Even in the case where pilot injection is performed, fuel injection control can be performed with extremely high precision.
  • the amounts of decrease in fuel injection pressure resulting from leakage of fuel are securely estimated, and the respective injection periods TQPLT, TQMAIN are corrected based on the amounts of decrease in fuel injection pressure.
  • the amount of decrease in fuel injection pressure resulting from pilot injection as well as leakage of fuel is taken into account.
  • the pressure change amount DPCRMAIN from detection of the actual fuel pressure PCR to the start of main injection is estimated based on the fuel leakage amount QLEAKMAIN and the pilot injection amount QPLT.
  • the pressure change amount DPCRMAIN can be estimated based only on the fuel leakage amount QLEAKMAIN or on the pilot injection amount QPLT.
  • the pressure change amount DPCRMAIN may also be estimated based only on the fuel leakage amount QLEAKMAIN or on the pilot injection amount QPLT.
  • a fuel force-feed amount from detection of the actual fuel pressure PCR to the start of main injection may be calculated.
  • the pressure change amount DPCRMAIN may be estimated based on the fuel force-feed amount or on the pilot injection amount QPLT as well as the fuel leakage amount QLEAKMAIN.
  • the actual fuel pressure PCR is preliminarily corrected based on the respective pressure change amounts DPCRPLT, DPCRMAIN, and the fuel injection periods during pilot injection and main injection (the pilot injection period TQPLT, the main injection period PCRMAIN) are calculated based on the values after such correction (the pilot injection fuel pressure PCRPLT, the main injection fuel pressure PCRMAIN).
  • the correction values relating to the pilot injection period TQPLT and the main injection period TQMAIN may be calculated based on the respective pressure change amounts DPCRPLT, DPCRMAIN, and the respective fuel injection periods TQPLT, TQMAIN may be corrected based on those correction values.
  • pilot injection is performed only once prior to main injection.
  • the pilot injection may be performed a plurality of times prior to main injection.
  • the subsequent pilot injection is performed such that the fuel injection period during that pilot injection is corrected based on a change in fuel injection pressure that is estimated based on a total amount of fuel injection during the previously performed pilot injection.
  • a fifth embodiment of the present invention will now be described focusing on a difference between the second and fifth embodiments.
  • the change in fuel injection pressure resulting from force-feeding of fuel or leakage of fuel is estimated.
  • the final injection period TQFIN is further corrected based on the change in fuel injection pressure, whereby the precision of fuel injection control is further enhanced.
  • Fig. 17 is a flowchart showing a process of estimating a change in fuel injection pressure during the fuel injection period (hereinafter referred to as "a pressure change amount DPCRINJ"). The respective processings shown in this flowchart are carried out following the processing in step 412, as part of a series of processings shown in the flowchart of Fig. 10.
  • step 420 the ECU 160 adds the actual fuel pressure PCR to the pressure change amount DPCR calculated through the processing in step 412. Based on the sum (PCR+DPCR) and the fuel temperature THF, the ECU 160 again calculates a volume elasticity coefficient E such that the volume elasticity coefficient E corresponds to a value at the time of the start of fuel injection.
  • step 422 a fuel leakage amount QLEAKINJ during the fuel injection period is calculated based on the basic injection period TQFINB and the fuel temperature THF. Then in step 424, it is determined whether or not the timing for starting force-feeding fuel from the fuel pump 30 is advanced with respect to the timing for starting fuel injection, namely, whether or not force-feeding of fuel is carried out prior to the start of fuel injection. If it is determined that force-feeding of fuel is carried out prior to the start of fuel injection, fuel is always force-fed during the fuel injection period. Therefore, in step 426, the ECU 60 converts the basic injection period TQFINB into a crank angle CA based on the engine rotational speed NE, and sets the converted value as a force-feed period APUMPINJ during the fuel injection period.
  • step 428 a fuel force-feed amount QPUMPINJ during the fuel injection period is calculated according to a calculation formula (11) shown below.
  • QPUMPINJ APUMPINJ ⁇ KQPUMP
  • step 424 if it is determined in step 424 that force-feeding of fuel is not carried out prior to the start of fuel injection, the ECU 60 shifts the processing to step 430.
  • step 430 the ECU 60 calculates a fuel injection termination period based on the fuel injection starting timing, the basic injection timing TQFINB and the engine rotational speed NE, using the crank angle CA as a unit.
  • step 432 by comparing the fuel injection termination period with the timing for starting force-feeding fuel from the fuel pump 30, it is determined whether or not force-feeding of fuel is started during the fuel injection period. If it is determined herein that force-feeding of fuel is started during the fuel injection period, a period (crank angle CA) from the force-feed starting timing to the fuel injection termination period is calculated in step 434 as a force-feed period APUMPINJ during the fuel injection period. Then in step 436, a fuel force-feed amount QPUMPINJ during the fuel injection period is calculated according to the aforementioned calculation formula (11).
  • step 432 determines whether force-feeding of fuel is not started during the fuel injection period. If it is determined in step 432 that force-feeding of fuel is not started during the fuel injection period, the force-feed period does not overlap with the fuel injection period. Thus, in step 435, the ECU 60 sets the fuel force-feed amount QPUMPINJ during the fuel injection period to zero.
  • step 440 a pressure change amount DPCRINJ during the fuel injection period according to a calculation formula (12) shown below.
  • DPCRINJ E ⁇ (QPUMPINJ-QLEAKINJ)/VCR
  • step 442 the ECU 60 calculates an average pressure change amount DPCRAVE based on the already-calculated pressure change amount DPCR during the pressure change estimation period and the pressure change amount DPCRINJ during the aforementioned fuel injection period, according to a calculation formula (13) shown below.
  • DPCRAVE DPCR+DPCRINJ/2
  • the average pressure change amount DPCRAVE is a mean value of the pressure change amount DPCR from detection of the actual fuel pressure PCR to the start of fuel injection (i.e. during the pressure change estimation period APCR) and the pressure change amount (DPCR+DPCRINJ) from detection of the actual fuel pressure PCR to the termination of fuel injection.
  • step 500 After the average pressure change amount DPCRAVE has been thus calculated, the processings following step 500 shown in Fig. 9 are carried out.
  • an injection period correction value TQFINH is calculated based on the aforementioned average pressure change amount DPCRAVE, in place of the pressure change amount DPCR during the pressure change estimation period APCR.
  • the basic injection period TQFINB is corrected based on the change in fuel injection pressure (the pressure change amount DPCRINJ) during the fuel injection period as well as the change in fuel injection pressure (the pressure change amount DPCR) during the pressure change estimation period APCR.
  • the fuel force-feed amount QPUMP and the fuel leakage amount QLEAK are referred to.
  • both the amount of a rise in fuel injection pressure resulting from force-feeding of fuel and the amount of a fall in fuel injection pressure resulting from leakage of fuel can be reflected on the pressure change amount DPCRINJ. Accordingly, it is possible to inhibit the actual fuel injection amount from becoming greater than the required injection amount QFIN due to a rise in fuel injection pressure, or conversely, to inhibit the actual fuel injection amount from becoming smaller than the required injection amount QFIN due to a fall in fuel injection pressure.
  • the pressure change amount DPCRINJ during the fuel injection period is estimated based on the fuel force-feed amount QPUMPINJ and the fuel leakage amount QLEAKINJ.
  • the pressure change amount DPCRINJ may be estimated based only on the fuel force-feed amount QPUMPINJ or only on the fuel leakage amount QLEAKINJ.
  • an amount of change in fuel injection pressure resulting from force-feeding of fuel or leakage of fuel during the pilot injection period or the main injection period may be estimated, and the pilot injection period TQPLT and the main injection period TQMAIN may further be corrected based on the thus-estimated amount of change in fuel injection pressure.
  • the fuel force-feed amount of the fuel pump 30 is calculated on the assumption that the fuel force-feed rate (KQPUMP) is constant.
  • the fuel force-feed amount can be calculated by referring to a map or the like that shows the fuel force-feed rate in relation to the timing for starting force-feeding of fuel.
  • the fuel injection amount is controlled based on a fuel injection period, namely, on an open-valve period of the injectors 112.
  • the fuel injection amount can be controlled based not only on the open-valve period but also on an opening degree of the injectors 112. In this case, it may be possible to correct a command value for the opening degree of the injectors 112 based on a change in fuel injection pressure.
  • a diesel engine is shown as an example of an internal combustion engine to which the fuel injection control apparatus of the present invention is applied.
  • the present invention can also be applied to a direct-injection gasoline engine wherein fuel is directly injected into combustion chambers.

Claims (22)

  1. Appareil de commande d'injection de carburant à accumulateur comprenant :
    un moyen de détection (14) pour détecter une pression de carburant sur une ligne d'accumulateur (4) ;
    un moyen d'estimation (22) pour estimer une pression de carburant injecté dans un moteur (1) ;
    un moyen de calcul de quantité de commande d'injection de carburant (21) pour calculer une quantité de commande d'injection de carburant basée sur la pression de carburant détectée ou sur la pression de carburant estimée ; et
    un moyen d'injection de carburant pour injecter le carburant dans le moteur basé sur la quantité de commande d'injection de carburant calculée dans lequel
    le moyen de calcul de la quantité de commande d'injection de carburant (21) détermine laquelle de la pression de carburant détectée et de la pression de carburant estimée doit être utilisée, basée sur un temps d'injection de carburant du moyen d'injection.
  2. Appareil de commande d'injection de carburant à accumulateur selon la revendication 1, caractérisé en ce que :
    le moyen de détection (14) détecte une pression de carburant à un premier instant (t1) ;
    le moyen d'injection de carburant (2) injecte le carburant à un deuxième instant (t2) qui est postérieur au premier instant ; et
    le moyen de calcul de la quantité de commande d'injection (21) calcule la quantité de commande d'injection de carburant basée sur la pression de carburant détectée, si un traitement arithmétique de la pression de carburant détectée au premier instant se termine plus tôt que le deuxième instant.
  3. Appareil de commande d'injection de carburant à accumulateur selon revendication 2, caractérisé en ce que :
    le moyen de calcul de la quantité de commande d'injection de carburant (21) détermine laquelle de la pression de carburant détectée ou de la pression de carburant estimée doit être utilisée, basée sur un premier temps (T1) à partir du premier instant (t1) au deuxième instant (t2) et sur un deuxième temps (T2) nécessaire pour le traitement arithmétique.
  4. Appareil de commande d'injection de carburant à accumulateur selon revendication 3, caractérisé en ce que :
    le moyen de calcul de la quantité de commande d'injection de carburant (21) calcule la quantité de commande d'injection de carburant utilisant la pression de carburant détectée, si le premier temps (T1) est supérieur au deuxième temps (T2).
  5. Appareil de commande d'injection de carburant à accumulateur selon revendication 1, caractérisé en ce que :
    le moyen de calcul de la quantité de commande d'injection de carburant (21) détermine laquelle de la pression de carburant détectée ou de la pression de carburant estimée doit être utilisée pour calculer la quantité de commande d'injection de carburant, basée sur la vitesse de rotation du moteur (1).
  6. Appareil de commande d'injection de carburant à accumulateur selon revendication 5, caractérisé en ce que :
    le moyen de calcul de la quantité de commande d'injection de carburant (21) calcule la quantité de commande d'injection de carburant utilisant la pression de carburant détectée, si la vitesse de rotation du moteur (1) est inférieure à une valeur prédéterminée.
  7. Appareil de commande d'injection de carburant à accumulateur selon revendication 1, caractérisé en ce que :
    le moyen d'estimation (22) calcule la pression de carburant basée sur un état de fonctionnement d'une pompe (7) d'alimentation du carburant sur la ligne d'accumulateur (14) et sur un coefficient d'élasticité volumique de carburant.
  8. Appareil de commande d'injection de carburant à accumulateur selon les revendications 1 à 7, caractérisé en ce que :
    la quantité de commande d'injection de carburant est une quantité d'injection de carburant.
  9. Appareil de commande d'injection de carburant à accumulateur selon la revendication 1, caractérisé en ce que :
    le moyen d'estimation (22) estime la pression de carburant basée sur la quantité de carburant à alimentation forcée par la pompe (7) pour alimenter le carburant dans la ligne d'accumulateur (14) pendant une période allant de la détection de la pression du carburant au début de l'injection du carburant.
  10. Appareil de commande d'injection du carburant à accumulateur selon la revendication 1, caractérisé en ce que :
    le moyen d'estimation (22) estime la pression du carburant basée sur une quantité de carburant fuyant de la ligne d'accumulateur (14).
  11. Appareil de commande d'injection de carburant à accumulateur selon les revendications 1 à 10, caractérisé en ce que :
    le moyen d'estimation (22) estime une pression de carburant basée sur un changement de pression de carburant pendant une période d'injection de carburant.
  12. Procédé de commande d'injection de carburant caractérisé par les étapes consistant à :
    détecter une pression de carburant dans une ligne d'accumulateur (4) ;
    estimer une pression de carburant injectée dans un moteur (1) ;
    calculer une quantité de commande d'injection de carburant basée sur la pression de carburant détectée ou sur la pression de carburant estimée ; et
    injecter le carburant dans le moteur, basé sur la quantité de commande d'injection de carburant calculée, avec une autre étape consistant à :
    déterminer laquelle de la pression de carburant détectée et de la pression de carburant estimée doit être utilisée, en se basant sur un moment d'injection de carburant d'un moyen d'injection.
  13. Procédé selon la revendication 12, caractérisé par les étapes consistant à :
    détecter une pression de carburant lors d'un premier instant (t1) ;
    injecter le carburant lors d'un deuxième instant (t2) qui est postérieur au premier instant ; et
    calculer la quantité de commande d'injection de carburant basée sur la pression de carburant détectée, si un traitement arithmétique de la pression de carburant détectée lors du premier instant est terminé plus tôt que le deuxième instant.
  14. Procédé selon revendication 13 caractérisé par l'étape consistant à :
    déterminer laquelle de la pression de carburant détectée et de la pression de carburant estimée doit être utilisée, basée sur un premier temps (T1) à partir du premier instant (t1) au deuxième instant (t2) et sur un deuxième temps (T2) nécessaire au traitement arithmétique.
  15. Procédé selon revendication 14, caractérisé par l'étape consistant à :
    calculer la quantité de commande d'injection de carburant utilisant la pression de carburant détectée, si le premier temps (T1) est supérieur au deuxième temps (T2).
  16. Procédé selon revendication 12, caractérisé par l'étape consistant à :
    déterminer laquelle de la pression de carburant détectée et de la pression de carburant estimée doit être utilisée pour calculer la quantité de commande d'injection de carburant, basée sur une vitesse de rotation du moteur (1).
  17. Procédé selon revendication 16, caractérisé par l'étape consistant à :
    calculer la quantité de commande d'injection de carburant utilisant la pression de carburant détectée, si la vitesse de rotation du moteur (1) est inférieure à une valeur prédéterminée.
  18. Procédé selon revendication 12, caractérisé par l'étape consistant à :
    calculer la pression de carburant basée sur un état de fonctionnement d'une pompe (7) d'alimentation du carburant dans la ligne d'accumulateur (14) et sur un coefficient d'élasticité volumique du carburant.
  19. Procédé selon les revendications 12 à 18, caractérisé en ce que :
    la quantité de commande d'injection de carburant est une quantité d'injection de carburant.
  20. Procédé selon revendication 12 caractérisé par l'étape consistant à :
    estimer la pression du carburant basée sur une quantité de carburant à alimentation forcée à l'aide d'une pompe (7) pour alimenter le carburant dans la ligne d'accumulateur (14) pendant une période allant de la détection de la pression du carburant au début de l'injection du carburant.
  21. Procédé selon revendication 12, caractérisé par l'étape consistant à :
    estimer la pression de carburant basée sur une quantité de carburant fuyant de la ligne d'accumulateur (14) .
  22. Procédé selon les revendications 12 à 21, caractérisé par l'étape consistant à :
    estimer une pression de carburant basée sur un changement de pression de carburant pendant une période d'injection de carburant.
EP20000100581 1999-01-25 2000-01-12 Dispositif et procédé de commande d'injection de combustible du type à accumulation Expired - Lifetime EP1022452B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP1632399A JP4055279B2 (ja) 1999-01-25 1999-01-25 蓄圧式燃料噴射制御装置
JP1632399 1999-01-25
JP6028299 1999-03-08
JP06028299A JP4280350B2 (ja) 1999-03-08 1999-03-08 高圧燃料噴射系の燃料噴射制御装置

Publications (3)

Publication Number Publication Date
EP1022452A2 EP1022452A2 (fr) 2000-07-26
EP1022452A3 EP1022452A3 (fr) 2002-01-30
EP1022452B1 true EP1022452B1 (fr) 2003-10-01

Family

ID=26352649

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20000100581 Expired - Lifetime EP1022452B1 (fr) 1999-01-25 2000-01-12 Dispositif et procédé de commande d'injection de combustible du type à accumulation

Country Status (3)

Country Link
EP (1) EP1022452B1 (fr)
DE (1) DE60005575T2 (fr)
ES (1) ES2204365T3 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6997164B2 (en) 2002-11-28 2006-02-14 Stmicroelectronics S.R.L. Virtual pressure sensor for a common rail injection system
US7210459B2 (en) 2004-04-22 2007-05-01 Denso Corporation Common-rail fuel injection system

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19909955B4 (de) * 1999-03-06 2014-01-23 Robert Bosch Gmbh Verfahren und Vorrichtung zum transienten Betrieb einer Brennkraftmaschine insbesondere eines Kraftfahrzeugs
DE10212508A1 (de) * 2002-03-21 2003-10-02 Bosch Gmbh Robert Verfahren und Vorrichtung zur Steuerung der Kraftstoffzumessung in eine Brennkraftmaschine
EP1359316B1 (fr) * 2002-05-03 2007-04-18 Delphi Technologies, Inc. Système d'injection de carburant
JP4333619B2 (ja) * 2005-04-08 2009-09-16 株式会社デンソー 筒内噴射式の内燃機関の始動制御装置
JP4951380B2 (ja) 2007-03-26 2012-06-13 日立オートモティブシステムズ株式会社 高圧燃料系の制御装置
DE102010018467B4 (de) * 2010-04-27 2012-03-01 Continental Automotive Gmbh Verfahren zum Betreiben einer Brennkraftmaschine und Brennkraftmaschine
GB2534398A (en) * 2015-01-22 2016-07-27 Gm Global Tech Operations Method of operating an internal combustion engine
DE102016224481A1 (de) * 2016-12-08 2018-06-14 Robert Bosch Gmbh Verfahren zur Prädiktion eines Drucks in einem Kraftstoffinjektor

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0765540B2 (ja) * 1988-09-21 1995-07-19 松下電器産業株式会社 エンジン制御装置
JPH05106495A (ja) * 1991-10-15 1993-04-27 Nippondenso Co Ltd 内燃機関の蓄圧式燃料噴射装置
JP2991574B2 (ja) 1992-09-14 1999-12-20 株式会社デンソー 内燃機関の蓄圧式燃料噴射制御装置
IT1268026B1 (it) * 1994-03-01 1997-02-20 Fiat Ricerche Sistema elettronico per il controllo della pressione di iniezione in transitorio.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6997164B2 (en) 2002-11-28 2006-02-14 Stmicroelectronics S.R.L. Virtual pressure sensor for a common rail injection system
US7210459B2 (en) 2004-04-22 2007-05-01 Denso Corporation Common-rail fuel injection system

Also Published As

Publication number Publication date
ES2204365T3 (es) 2004-05-01
DE60005575D1 (de) 2003-11-06
EP1022452A2 (fr) 2000-07-26
EP1022452A3 (fr) 2002-01-30
DE60005575T2 (de) 2004-08-05

Similar Documents

Publication Publication Date Title
EP0899443B1 (fr) Procédé et dispositif d'injection de carburant d'un moteur à combustion
US20060005816A1 (en) Fuel injection system
EP2518303B1 (fr) Dispositif, et commande, d'alimentation en carburant pour moteur à combustion interne
US7007662B2 (en) Fuel supply apparatus for internal combustion engine
US7472689B2 (en) Fuel injection system
EP1030048B1 (fr) Dispositif de commande de pression pour un system d'injection de carburant à haute pression
JP4158272B2 (ja) 高圧燃料噴射系の異常判定方法
JP2005307747A (ja) 内燃機関の燃料供給装置
EP1022452B1 (fr) Dispositif et procédé de commande d'injection de combustible du type à accumulation
EP1201905B1 (fr) Dispositif de detection de défaut dans un système d'alimentation en carburant haute pression
JP2000303887A (ja) 内燃機関の燃料噴射装置
JP4280350B2 (ja) 高圧燃料噴射系の燃料噴射制御装置
EP1036923B1 (fr) Méthode de détermination des anormalités dans un système d'injection de combustible à haute pression
EP1371836A2 (fr) Système de commande d'alimentation en carburant de moteur à explosion interne
JP4424380B2 (ja) 噴射量制御装置およびそれを用いた燃料噴射システム
JP3587011B2 (ja) 内燃機関の制御装置
JPH1054317A (ja) 燃料供給装置
JP4055279B2 (ja) 蓄圧式燃料噴射制御装置
JP4281825B2 (ja) 高圧燃料噴射系の燃料圧制御装置
JP4597220B2 (ja) 内燃機関の制御装置
JP4349339B2 (ja) 内燃機関の噴射量制御装置
JP4753078B2 (ja) 内燃機関の制御装置
JP2006070845A (ja) コモンレール式燃料噴射装置
JP2007120395A (ja) 燃料噴射装置

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20000210

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE ES FR GB IT

Kind code of ref document: A2

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

AKX Designation fees paid

Free format text: DE ES FR GB IT

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE ES FR GB IT

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 60005575

Country of ref document: DE

Date of ref document: 20031106

Kind code of ref document: P

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2204365

Country of ref document: ES

Kind code of ref document: T3

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20040702

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

REG Reference to a national code

Ref country code: GB

Ref legal event code: 746

Effective date: 20110104

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20110115

Year of fee payment: 12

Ref country code: FR

Payment date: 20110128

Year of fee payment: 12

Ref country code: DE

Payment date: 20110105

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20110121

Year of fee payment: 12

Ref country code: GB

Payment date: 20110112

Year of fee payment: 12

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20120112

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20120928

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120112

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120801

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60005575

Country of ref document: DE

Effective date: 20120801

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120112

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120131

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20130708

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120113