EP0860601B1 - Système d'injection de combustible pour moteur à combustion interne - Google Patents

Système d'injection de combustible pour moteur à combustion interne Download PDF

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Publication number
EP0860601B1
EP0860601B1 EP19980102970 EP98102970A EP0860601B1 EP 0860601 B1 EP0860601 B1 EP 0860601B1 EP 19980102970 EP19980102970 EP 19980102970 EP 98102970 A EP98102970 A EP 98102970A EP 0860601 B1 EP0860601 B1 EP 0860601B1
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EP
European Patent Office
Prior art keywords
fuel
fuel injection
pressure
reservoir
amount
Prior art date
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Application number
EP19980102970
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German (de)
English (en)
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EP0860601A2 (fr
EP0860601A3 (fr
Inventor
Motoichi Murakami
Tomihisa Oda
Yuichi Hokazono
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Toyota Motor Corp
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Toyota Motor Corp
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Publication of EP0860601A3 publication Critical patent/EP0860601A3/fr
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    • 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
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
    • 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
    • F02D41/3827—Common rail control systems for diesel engines
    • 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
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D2041/224—Diagnosis of the fuel system
    • 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
    • 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
    • F02D2200/0606—Fuel temperature

Definitions

  • the present invention relates to a fuel injection system for an internal combustion engine and, particularly, to a fuel injection system including means for detecting failures of the fuel injection system.
  • a common rail type fuel injection system for an internal combustion engine is known in the art.
  • a common rail type fuel injection system includes a common rail which stores high pressure fuel fed from a high pressure fuel pump. Fuel injection valves of the engine are connected to the common rail and inject the high pressure fuel in the reservoir (i.e., the common rail) into the respective cylinders of the engine. Namely, the common rail acts as a reservoir which stores high pressure fuel and distributes it to the respective fuel injection valves.
  • a common rail type fuel injection system provided with means for detecting failures of the fuel injection system, such as a leak from the common rail or a sticking of the fuel injection valve, is also known.
  • This kind of the common rail type fuel injection system is, for example, disclosed in Japanese Unexamined Patent Publication (Kokai) No. 8-4577.
  • the fuel injection system in the '577 publication is provided with a pressure sensor for detecting the pressure of the fuel in the common rail and measures the difference of the pressures in the common rail before and after the fuel injection from the fuel injection valve, i.e., the pressure drop in the common rail during the fuel injection period. Further, the system in the '577 publication is provided with failure detecting means for estimating the pressures in the common rail before and after the fuel injection based on the operating condition of the engine in order to estimate the pressure drop during the fuel injection period, and for determining that the fuel injection system has failed when the difference between the measured pressure drop and the estimated pressure drop is larger than a predetermined limit.
  • Q is a fuel injection amount per one fuel injection determined from the operating condition (the load condition) of the engine
  • K is a bulk modulus of elasticity of the fuel
  • V is a total volume of a high pressure part of the fuel injection system including the common rail volume, the volume of a high pressure supply line to the common rail and the volume of a fuel injection line from the common rail to the fuel injection valves.
  • constant values are used for the bulk modulus K and the volume V. Namely, it is considered that the pressure drop during the fuel injection period is equal to the pressure drop caused by the fuel flow out from the common rail.
  • the pressure drop during the fuel injection period must be the same as ⁇ P. If the estimated ⁇ P is different from the measured ⁇ P, it is considered that the amount of the fuel flow out from the common rail during the fuel injection does not agree with the calculated (i.e., target) fuel injection amount Q. For example, if the measured pressure drop ⁇ P is larger than the estimated pressure drop ⁇ P by a certain amount, since this means that the amount of the fuel flow out from the common rail is larger than the target value of the fuel injection amount, it is considered the failure of the fuel injection system such as the sticking of the fuel injection valve at the opening position has occurred.
  • the '577 publication assumes that the bulk modulus of elasticity K of the fuel is constant regardless of the pressure and temperature of the fuel.
  • the bulk modulus of elasticity K of the fuel changes in accordance with the pressure and temperature of the fuel. Therefore, in the actual system, the pressure drop during the fuel injection period takes different values according to the pressure and temperature of the fuel in the common rail even if the fuel injection amount is the same.
  • the measured pressure drop ⁇ P increases as the pressure in the common rail increases even if the fuel injection amount is the same. Therefore, if a constant value of the bulk modulus of elasticity K is used for estimating the pressure drop ⁇ P, it is difficult to determine the failure of the fuel injection system correctly if the pressure in the common rail changes over a wide range.
  • the pressure of the fuel in the common rail varies in a very wide range in order to control both the fuel injection amount and the rate of injection in accordance with the operating condition of the engine.
  • the pressure in the common rail is changed from 10 Mpa to 150 Mpa.
  • the determination of the failure using the method in the '577 publication is not possible if a constant value is used for the bulk modulus of elasticity.
  • the object of the present invention is to provide means for correctly determining a failure of the fuel injection system even if the pressure of the fuel varies in a very wide range.
  • a fuel injection system for an internal combustion engine which includes, a reservoir for storing pressurized fuel, a fuel injection valve connected to the reservoir and injecting fuel in the reservoir into an internal combustion engine at a predetermined timing, a fuel pump for feeding pressurized fuel to the reservoir at a predetermined timing in order to maintain the pressure of the fuel in the reservoir at a predetermined value, pressure detecting means for detecting the pressure of the fuel in the reservoir, bulk modulus detecting means for detecting a bulk modulus of elasticity of the fuel in the reservoir, and failure determining means for determining whether the fuel injection system of the engine has failed based on the bulk modulus detected by the bulk modulus detecting means and the change in the pressure of the fuel in the reservoir during the operation of the engine.
  • the bulk modulus detecting means detects the bulk modulus of elasticity of the fuel in the reservoir, and this detected bulk modulus is used for determining whether the fuel injection system has failed.
  • the bulk modulus detecting means in this invention may detect the bulk modulus of elasticity indirectly based on the pressure or the temperature (or the both) of the fuel in the reservoir.
  • the failure detecting means in this invention may determine the failure of the fuel injection system, for example, by comparing the pressure change in the reservoir during the fuel injection period or the fuel feed period with the measured pressure change in the reservoir.
  • the bulk modulus of elasticity used for the determination of the failure is suitably changed in accordance with the actual pressure and temperature of the fuel in the reservoir, the failure of the system can be correctly determined even if the pressure and temperature of the fuel in the reservoir change in a very wide range.
  • Fig. 1 shows a general configuration of an embodiment of the fuel injection system of the present invention when it is applied to a diesel automobile engine.
  • reference numeral 10 designates an internal combustion engine (in this embodiment, a four-cylinder four-cycle diesel engine).
  • Numeral 1 designates fuel injection valves which inject fuel into the respective cylinders of the engine 10 and 3 designates a common rail (a reservoir) to which the fuel injection valves 1 are connected. As explained later, the common rail 3 stores the pressurized fuel fed from a high pressure fuel pump 5 and distributes it to the respective fuel injection valves 1.
  • numeral 7 represents a fuel tank which stores fuel (in this embodiment, diesel fuel) for the engine
  • 9 represents a low pressure feed pump which supply the fuel in the fuel tank 7 to the high pressure fuel pump 5.
  • a fuel filter 9b is disposed on the fuel supply line 13 from the low pressure feed pump 9 to the high pressure fuel pump 5.
  • the fuel in the tank 7 is pressurized to a constant pressure by the feed pump 9 and filtered by the fuel filter 9b to eliminate foreign matter and water in the fuel and it is supplied to the high pressure fuel pump 5 via the supply line 13.
  • Fuel is further pressurized by the high pressure fuel pump 5 and fed to the common rail 3 through a check valve 15 and a high pressure line 17. From the common rail 3, fuel is injected into the respective cylinders through the respective fuel injection valves.
  • Numeral 19 in Fig. 1 shows a fuel return line for returning the fuel from the fuel injection valves 1 to the fuel tank 7. The return fuel from the fuel injection valve will be explained later in detail.
  • an electronic control unit (ECU) 20 is provided for controlling the engine 10.
  • the ECU 20 may be constructed as a microcomputer of a known type including a read-only memory (ROM), a random-access memory (RAM), a microprocessor (CPU) and input/output ports all connected to each other by a bi-directional bus. Further, ECU 20 is provided with a backup RAM capable of maintaining the contents or its memory even if a main switch of the engine is turned off.
  • the ECU 20 performs a fuel pressure control which adjusts the fuel pressure in the common rail in accordance with the engine load and speed by controlling the operation of the intake control valve 5a of the high pressure fuel pump 5. Further, the ECU 20 performs a fuel injection control which controls the fuel injection amount by adjusting the opening period of the fuel injection valve 1.
  • the ECU 20 in this embodiment functions as failure determining means for determining whether the fuel injection system, including the fuel pump 5, the common rail 3 and fuel injection valves 1 etc., has failed.
  • voltage signals corresponding to the pressure and the temperature of the fuel in the common rail 3 are supplied to the input port of the ECU 20 from a fuel pressure sensor 31 and a fuel temperature sensor 33 each disposed on the common rail 3 via an AD converter 34.
  • An accelerator signal which represents the amount of depression of an accelerator pedal, by the operator of the automobile, is also supplied to the input port of the ECU 20 via the AD converter 34 from an accelerator sensor 35 disposed near the accelerator pedal (not shown).
  • a fuel supply pressure sensor 39 is disposed on the fuel supply line 13 between the fuel filter 9b and the high pressure fuel pump 5, and a voltage signal corresponding to the fuel supply pressure to the fuel pump 5 is supplied from the sensor 39 to the input port of the ECU 20 via the AD converter 34.
  • crank angle signals are supplied from a crank angle sensor 37 to the input port of the ECU 20.
  • the crank angle sensor 37 is actually composed of two sensors. One is a reference position sensor which is disposed near a camshaft of the engine and generates a reference pulse signal when the crankshaft reaches a reference rotating position (for example, when the first cylinder of the engine 10 reaches the top dead center of the compression stroke), and another is a rotation angle sensor which generates a rotating pulse signal at a predetermined angle of rotation of the crankshaft.
  • crank angle signals i.e., the reference pulse signal and the rotating pulse signal are also supplied to the input port of the ECU 20.
  • the output port of the ECU 20 is connected to the fuel injection valves 1 and a solenoid actuator of the intake control valve 5a of the high pressure fuel pump 5 via respective drive circuits 40 and controls the operation of the fuel injection valve 1 and the fuel feed amount from the high pressure fuel pump 5 to the common rail 3, respectively.
  • the high pressure fuel pump 5 in this embodiment is a piston type pump having two cylinders.
  • the pistons of the pump 5 are driven by cams formed on the driving shaft and reciprocate in the respective cylinders.
  • Intake control valves 5a which are opened and closed by the respective solenoid actuator are disposed at the intake ports of the respective cylinders.
  • the driving shaft of the pump 5 in this embodiment is driven by the crankshaft of the engine 10 and rotates synchronously with the crankshaft at the one-half speed thereof.
  • each of the cams formed on the driving shaft has two cam lift portions, whereby the respective cylinders of the pump 5 discharge fuel once per one revolution of the crankshaft.
  • the pump 5, as a whole discharges 4 times per two revolution of the crankshaft.
  • the pump 5 is capable of feeding fuel to the common rail 3 at the timing synchronous with the strokes of the cylinders of the engine.
  • the pump 5 in this embodiment feeds fuel to the common rail at the timing immediately after the fuel injection of the respective cylinders.
  • the ECU 20 controls the amount of fuel fed to the common rail 3 by changing the timing where the intake control valve 5a closes during the discharge stroke of the pump cylinders. More specifically, the ECU 20 keeps the intake control valve 5a open by deenergizing the solenoid actuator during the inlet stroke and a part of the discharge stroke of the pump cylinder. When the intake control valve 5a is kept open, the fuel in the pump cylinder flows back to the fuel tank through the intake control valve during the discharge stroke, and the fuel in the pump cylinder is not fed to the common rail 3. When a predetermined time has lapsed from the beginning of the discharge stroke, the ECU 20 closes the intake control valve 5a by energizing the solenoid actuator.
  • the fuel trapped in the pump cylinder is pressurized by the piston and, when the pressure in the cylinder exceeds the pressure in the common rail 3, the pressurized fuel in the cylinder pushes open the check valve 15 and flows into the high pressure line 17.
  • the intake valve 5a is closed during the discharge stroke of the pump cylinder, fuel is fed to the common rail 3.
  • the valve 5a is kept at the closed position during the discharge stroke by the fuel pressure regardless of the actuation of the solenoid actuator. Therefore, the amount of the fuel fed to the common rail 3 is determined by the timing at which the intake control valve closes.
  • the ECU 20 in this embodiment controls the fuel feed amount to the common rail 3 by changing the timing for energizing the solenoid actuator of the intake control valve 5a.
  • the ECU 20 determines a target value of the common rail pressure based on the engine load and speed.
  • the relationships between the target value of the common rail pressure and the engine load and speed are determined in advance, and stored in the ROM of the ECU 20. Further, the ECU 20 controls the fuel feed amount of the high pressure fuel pump 5 so that the common rail pressure detected by the sensor 31 is kept at the target value.
  • the ECU 20 further calculates the fuel injection amount from the engine load and speed using a predetermined relationship, and controls the opening period of the fuel injection valves to inject the calculated amount of fuel from the fuel injection valves.
  • the ECU 20 in this embodiment adjusts the rate of injection of the fuel injection valves 1 in accordance with the operating condition of the engine by changing the common rail pressure, and adjusting the fuel injection amount in accordance with the operating condition of the engine by changing the common rail pressure and opening period of the fuel injection valve. Therefore, the common rail pressure in this embodiment changes in accordance with the operating condition in a very wide range (for example, from about 10 Mpa to about 150 Mpa).
  • the failure of the fuel injection system is determined based on at least one of the changes in the common rail pressure during the fuel injection period and the fuel feed period.
  • Fig. 2 schematically illustrates the change in the fuel pressure in the common rail 3 during one cycle composed of the fuel injection and the fuel feed.
  • the period PD represents a period in which fuel injection is performed by one of the fuel injection valves
  • the period PU represents a period in which the fuel feed is performed by the fuel pump 5 after each fuel injection.
  • the fuel injection from the fuel injection valves 1 and the fuel feed from the fuel pump 5 is performed at different timing so that the fuel injection period PD and the fuel feed period PU do not overlap each other.
  • PC1 0 represents the pressure in the common rail 3 immediately before the fuel injection (PD) starts
  • PC2 represents the pressure in the common rail after the fuel injection is completed and before the fuel feed (PU) starts
  • PC1 1 represents the pressure in the common rail after the fuel feed is completed and before the next fuel injection starts.
  • the change in the common rail pressure before and after the fuel injection i.e., the change in the pressure during the fuel injection period PD
  • the change in the common rail pressure before and after the fuel feed i.e., the change in the pressure during the fuel feed period PU
  • DPC12 PC2 - PC1 0
  • DPC21 PC1 1 - PC2
  • DPC12 is the change in the pressure during the fuel injection period PD
  • DPC21 is the change in the pressure during the fuel feed period PU.
  • This embodiment further calculates the estimated value DPD of the pressure change during the fuel injection period PD based on the target value of the fuel injection amount, and the estimated value DPU of the pressure change during the fuel feed period PU based on the target value of the fuel feed amount, respectively. By comparing the values DPC12 with DPD, or DPC21 with DPU, it is determined whether the fuel injection system has failed.
  • the estimated values of the pressure changes DPD and DPU are calculated by the methods explained below.
  • the pressure change DPD during the fuel injection period is calculated by the following formula.
  • DPD -(K/VPC) ⁇ QFINC
  • K is the bulk modulus of elasticity of the fuel
  • VPC is the volume of the high pressure part of the fuel injection system including the common rail 3
  • QFINC is a target value of the fuel injection amount expressed in the volume under the reference pressure (for example, 0.1 Mpa). Since the ECU 20 controls the fuel injection valves 1 so that the target fuel injection amount is injected, the amount of the fuel actually flowing out from the common rail 3 during the fuel injection period PD becomes the same as QFINC, and the estimated value DPD becomes the same as DPC12, unless failure occurs in the fuel injection valve or the common rail 3.
  • the estimated value DPU of the pressure change during the fuel feed period PU is calculated by the following formula.
  • DPU (K/VPC) ⁇ QPMD
  • QPMD is a target value for the fuel feed amount, i.e., the amount of the fuel flowing into the common rail 3 during the fuel feed period PU. Since the ECU 20 controls the intake control valve 5a of the fuel pump 5 so that the actual fuel feed amount agrees with the target value QPMD, the amount of fuel flowing into the common rail 3 becomes the same as QPMD, and the estimated value DPU becomes the same as the measured value DPC21, unless a failure occurs in the fuel pump 5 or the common rail 3.
  • the determination of the failure based on the change in the pressure during the fuel injection period using DPD and DPC12 and the determination of the failure based on the change in the pressure during the fuel feed period using DPU and DPC21 can be performed independently of each other.
  • the type of the failure such as the failed portion of the fuel injection system can be identified by comparing the results of the determination by the both methods. The detail of the method for identifying the type of the failure will be explained later in detail.
  • Fig. 3 shows a typical change in the bulk modulus of elasticity of fuel (diesel fuel) in accordance with the pressure and the temperature.
  • the bulk modulus of elasticity of diesel fuel increases as the pressure increases, and decreases as the temperature increases.
  • the rate of change in the bulk modulus of elasticity associated with the changes in the pressure and the temperature is relatively small. Therefore, when the pressure and the temperature of fuel changes in a relatively narrow range, the errors in the values DPD and DPU are not large even if the bulk modulus of elasticity is assumed to be a constant.
  • the bulk modulus of elasticity of the diesel fuel used for the engine 1 is measured in advance, under various pressure and temperature conditions within a possible range in the operation of the engine. And the measured values of the bulk modulus are stored in the ROM of the ECU 20 in the form of a numerical map using the pressure and the temperature.
  • the ECU 20 determines the value of the bulk modulus of elasticity of the fuel in the common rail 3 from the numerical map using the fuel pressure PC and the fuel temperature THF in the common rail 3 detected by the fuel pressure sensor 31 and the fuel temperature sensor 33, and calculates DPD and DPU from the above-explained formulas using the determined value of the bulk modulus of elasticity.
  • Fig. 4 is a flowchart explaining an embodiment of the failure determining operation based on the change in the pressure of the fuel in the common rail 3 during the fuel injection period (DPD, DPC12). This operation is performed by a routine executed by the ECU 20 at predetermined intervals (for example, at every predetermined rotation angle of the crankshaft).
  • crank angle CA1 0 corresponds to the timing immediately before the starts of the fuel injection in the respective cylinders, i.e., the sampling timing of PC1 0 in Fig. 2.
  • the crank angle CA2 corresponds to the timing immediately before the start of the fuel feed in the respective cylinders and corresponds to the sampling timing of PC2 in Fig. 2.
  • the newest values of PC1 0 , THF1 and PC2 are read and stored.
  • the bulk modulus of elasticity K of the fuel in the common rail 3 is determined based on the stored values of the pressure PC1 0 and the temperature THF1 of the fuel in the common rail 3.
  • the bulk modulus K is determined from the numerical map stored in the ROM of the ECU 20 using the values of PC1 0 and THF1 as explained before.
  • the ECU 20 calculates the fuel injection amount QFINC by a fuel injection amount calculation routine (not shown) based on the engine speed and the amount of depression of the accelerator pedal (accelerator signal).
  • the ECU 20 determines whether the difference dDPD exceeds a predetermined value R1. If dDPD > R1 at step 419, since this means that the amount of the fuel flowing out from the common rail 3 is larger than the normal amount (i.e., the target value of the fuel injection amount), the ECU 20 determines that the fuel injection system has failed, and sets the value of a failure flag XD to 1 at step 423. Further, if dDPD ⁇ R1 at step 419, the ECU 20 determines that the fuel injection system is normal, and sets the value of the flag XD to 1 at step 421.
  • failure flag XD When the failure flag XD is set to 1, an alarm is activated by another routine (not shown) in order to notify the driver of the automobile that a failure has occurred in the fuel injection system.
  • the result of the determination i.e., the value of the flag XD, may be stored in the backup RAM to facilitate future inspection and maintenance.
  • the value of the bulk modulus of elasticity of the fuel is determined based on the pressure PC1 0 and the temperature THF1 of the fuel before the fuel injection is performed, since the change in the pressure and temperature of the fuel during the fuel injection period is relatively small, the pressure (PC2) and the temperature of the fuel after the fuel injection may be used for determining the bulk modulus. Further, the average values of the pressures and temperatures before and after the fuel injection may be used for determining the bulk modulus.
  • Fig. 5 shows a flowchart explaining an embodiment of the failure determining operation based on the change in the pressure of the fuel in the common rail 3 during the fuel feed period (DPU, DPC21).
  • the operation in Fig. 5 is performed by a routine executed by the ECU 20 at a predetermined interval (for example, at every predetermined rotation angle of the crankshaft of the engine).
  • the estimated value DPU of the change in the pressure of the fuel during the fuel feed period is calculated on the basis of the bulk modulus of elasticity determined in a similar manner to that in the operation in Fig. 4, and determination is carried out based on the difference dDPU between the estimated value DPU and the actual value DPC21 of the pressure change.
  • Steps 503 through 509 represent the operations for reading the pressures PC1 1 and PC2 (Fig. 2) and temperature THF2.
  • CA2 in step 503 and CA1 1 in step 507 are crank angles corresponding to the timing after the fuel injection is completed and before the fuel feed starts and the timing immediately before the next fuel injection starts.
  • the bulk modulus of elasticity K of the fuel is determined in accordance with the pressure PC2 and the temperature THF2 of the fuel in the common rail 3 at the time after the fuel injection and before the fuel feed in this embodiment.
  • the pressure PC1 1 and the temperature THF1 of the fuel after the fuel feed is completed may be used for determining the value of the bulk modulus K.
  • the value of the failure flag XU similar to the flag XD in Fig. 4 is set to 1 (failed) or 0 (normal) at steps 523 or 521 based on whether the dDPU is larger than a predetermined value R2.
  • the bulk modulus of elasticity K of the fuel is determined based on both the pressure and the temperature of the fuel in the common rail 3.
  • the bulk modulus k may be determined based on only the pressure of the fuel assuming that the temperature of the fuel is constant.
  • the bulk modulus K may be determined based on only the temperature of the fuel assuming that the pressure of the fuel is constant.
  • DPD ⁇ (k/VPC) ⁇ QFINC
  • a certain amount of fuel is returned to the fuel tank associating with the fuel injection operation of the fuel injection valve. More specifically, in these types of fuel injection valves, the fuel injection valve is maintained at closed position by exerting fuel pressure both on the upper side and the lower side (the fuel injection port side) of the valve element in order to cancel the force exerted on the valve element by the fuel pressure.
  • the fuel on the upper side of the valve element is relieved through the fuel return line 19 via a solenoid valve in order to reduce the force exerted on the upper side of the valve element.
  • valve element By reducing the pressure on the upper side of the valve element, the valve element is moved by the fuel pressure exerting on the lower side of the element against the urging force of a spring, thereby the valve element opens the fuel injection port to inject the fuel. Therefore, in this type of the fuel injection valve, fuel is returned from the common rail 3 to the fuel tank by the fuel injection operation in addition to the fuel injected through the fuel injection valve.
  • the fuel return to the fuel tank in association with the fuel injection operation is referred to as “a dynamic fuel return”
  • the fuel constantly returned from the common rail to the fuel tank regardless of the fuel injection operation, such as the fuel leaked from the sliding parts is referred to as “a static fuel return”.
  • the dynamic fuel return amount and the static fuel return amount in addition to the fuel injection amount QFINC.
  • the dynamic fuel return amount QILD and the static fuel return amount QILS are considered when the estimated value DPD is calculated.
  • the dynamic fuel return amount QILD and the static fuel return amount QILS are calculated by the method explained below.
  • the dynamic fuel return amount QILD is the amount of the fuel returned to the fuel tank only when the fuel injection valve opens and is expressed by the amount of fuel returned to the tank by one fuel injection.
  • the dynamic fuel return amount QILD is a function of the length of the opening period of the fuel injection valve TQFIN (i.e., the length of the period in which the solenoid valve is energized for relieving the fuel on the upper side of the valve element of the fuel injection valve) and the fuel pressure immediately before the fuel injection starts (i.e., fuel pressure PC1 0 ).
  • the dynamic fuel return amount is measured in advance under various conditions of the fuel pressure and the opening period of the fuel injection valve, and the measured values of the dynamic fuel return amount are stored in the ROM of the ECU 20 in the form of a numerical map based on the fuel pressure PC1 0 and the fuel injection period TQFIN.
  • the dynamic fuel return amount QILD is determined from this numerical map using the fuel pressure PC1 0 and the fuel injection period TQFIN in the actual operation of the engine.
  • the static fuel return amount QILS is expressed by the total amount of the fuel leaked from the sliding parts during the period between the sampling point of PC1 0 and the sampling point of PC2 (Fig. 2).
  • the static fuel return amount QILS is a function of the fuel pressure PC1 0 , the fuel temperature THF1 (i.e., the viscosity of the fuel) and the engine speed NE (i.e., the time lapsed from the sampling point of PC1 0 to the sampling point PC2).
  • the static fuel return amount QILS is measured in advance under various conditions of the fuel pressure, the fuel temperature and the engine speed, and the values of the measured QILS are stored in the ROM of the ECU 20 in the form of a numerical map using the fuel pressure, the fuel temperature and the engine speed as the parameters.
  • the static fuel return amount QILS is determined from this numerical map using the fuel pressure PC1 0 and the fuel temperature THF1 and the engine speed NE in the actual operation of the engine.
  • Fig. 6 shows a flowchart of the calculation of the estimated pressure change DPD during the fuel injection period when taking QILD and QILS into consideration. This calculation is, for example, performed by a subroutine executed at step 413 in Fig. 4.
  • the opening period of the fuel injection valve i.e., the period for energizing the solenoid valve
  • TQFIN calculated by another routine (not shown) by ECU 20 and the engine speed NE are read in.
  • the dynamic fuel return amount QILD is determined from the numerical map for QILD stored in the ROM of the ECU 20 using the fuel pressure PC1 0 stored at step 403 (Fig. 4) and TQFIN.
  • the static fuel return amount QILS is determined from the numerical map for QILS stored in the ROM of the ECU 20 using the fuel temperature THF1 stored at step 405 (Fig. 4), the fuel pressure PC1 0 and the engine speed NE.
  • the fuel injection amount QFINC is read in, and at step 609, the pressure change during the fuel injection period DPD is calculated based on the values QFINC, QILD, QILS and the bulk modulus of elasticity K determined at step 411 in Fig. 4 by the following formula.
  • DPD -(k/VPC) ⁇ (QFINC + QILD + QILS)
  • the accuracy of the estimated value DPD of the pressure change during the fuel injection period can be improved by taking the amount of the fuel returned from the common rail into consideration.
  • the accuracy of the estimated value DPU can be also improved in a similar manner.
  • only the static fuel return amount QILS is to be considered as the amount of the fuel returned from the common rail because the fuel injection is not performed during the fuel feed period.
  • the amount of the fuel leaked from the fuel pump must be considered to calculate the fuel feed amount QPMD accurately.
  • the fuel feed amount QPMD from the fuel pump is expressed by the following formula.
  • QPMD QG - QD - QL
  • QG is a geometric discharge amount of the pump which corresponds to a displacement of the pump piston during the period in which the intake control valve of the pump cylinder opens.
  • the geometric discharge amount QG is a function of the basic timing (crank angle) TF at which the solenoid actuator of the intake control valve 5a is energized and the delay time TFD which is the difference between the basic timing TF and the timing at which the solenoid actuator is actually energized.
  • QD is a dead volume loss of the pump which represents the amount of the fuel remained in the pump cylinder when the pump piston reaches the top dead center.
  • the dead volume loss QD is a function of the fuel pressure PC1 1 at the end of the fuel feed period and the bulk modulus of elasticity of the fuel.
  • the fuel pressure PC2 at the beginning of the fuel feed period may be used instead of PC1 1 as an approximation.
  • QL represents the amount of the fuel leaked within the pump and is a function of the fuel pressure PC1 1 (or PC2), the fuel temperature THF2 (the viscosity of the fuel) and the pump speed (the engine speed) NE.
  • QG, QD and QL are measured in advance with various conditions of the respective parameters.
  • the measured values of QG, QD and QL are stored in the ROM of the ECU 20 in the form of numerical maps based on TF and TFD (in the case of QG), PC2 and K (in the case of QD) and PC2, THF2 and NE (in the case of QL).
  • the values of QG, QD and QL are determined from these numerical maps using the measured values of the respective parameters during the actual operation of the engine.
  • the actual fuel feed amount QPMD is accurately calculated by using the values QG, QD and QL determined in the actual operation of the engine.
  • Fig. 7 is a flowchart of the calculating operation of the estimated value DPU of the pressure change during the fuel feed period using the fuel feed amount QPMD which is calculated taking the amounts QG, QD, QL into the consideration. This operation is performed by a subroutine executed at step 513 in Fig. 5.
  • step 701 the basic timing TF for energizing the solenoid actuator of the intake control valve 5a, the delay time TFD and the engine speed NE are read in.
  • the basic timing TF and the delay time TFD are calculated in the pump control operation (not shown) performed by the ECU 20 based on the operating condition of the engine.
  • the static fuel return amount QILS is determined from the numerical map for QILS using the fuel pressure PC2 and the fuel temperature THF2 stored at step 505 in Fig. 5 and the engine speed NE. Further, the geometric discharge amount QG is determined from TF and TFD at step 705 based on the numerical map for QG stored in the ROM of the ECU 20. At step 707, the dead volume loss QD is determined from the fuel pressure PC2 and the bulk modulus of elasticity K of the fuel calculated at step 511 in Fig. 5 based on the numerical map for QD. The internal leak of the pump QL is determined at step 709 from the fuel pressure PC2, the fuel temperature THF2 and the engine speed NE based on the numerical map for QL.
  • the pressure change DPU in the fuel during the fuel feed period is calculated using the bulk modulus of elasticity K determined at step 511 in Fig. 5 and the static fuel return amount QILS and the actual fuel feed amount QPMD by the following formula.
  • DPU (K/VPC) ⁇ (QPMD - QILS)
  • QPMD in the formula represents the amount of the fuel flowing into the common rail during the fuel feed period
  • QILS represents the amount of the fuel flowing out from the common rail during the fuel feed period
  • the static fuel return amount QILS is determined from the numerical map based on the fuel pressure, the fuel temperature and the engine speed. Therefore, if the values of the fuel pressure, the fuel temperature and the engine speed are the same, the value of the static fuel return amount QILS always becomes the same regardless of the condition of the fuel injection valves.
  • the static fuel return amount is, as explained before, the amount of the fuel leaks from the clearances of the sliding parts of the fuel injection valves. Since the clearances of the sliding parts of the fuel injection valves change in accordance with the operation hours of the engine, the static fuel return amount also changes in accordance with the operation hours even if the operating conditions are the same.
  • the ECU 20 measures the actual values of QILS during the operation of the engine and learns the change in the QILS based on the measured values. Further, the ECU 20 uses the learned result when it determines the static fuel return amount QILS in order to increase the accuracy of the QILS. According to this embodiment, the actual changes in the static fuel return amount are incorporated into the calculated value of QILS and accuracy of the determination of the failure is increased.
  • Fig. 8 is a flowchart showing the learning operation of the static fuel return amount QILS according to this embodiment. This operation is performed by a routine executed by the ECU 20 at predetermined intervals.
  • the pressure change in the common rail is measured during the period in which neither the fuel injection nor the fuel feed is performed, and the static fuel return amount QILS is calculated based on the measured pressure change.
  • the total amount of the static fuel return amount during the period ⁇ T is a function of the fuel pressure PC in the common rail and the fuel temperature (the viscosity of the fuel)
  • the total amount QILS of the static fuel return amount in this period is expressed by a linear function of the pressure PC in the common rail, if the temperature of the fuel in this period is constant.
  • QILS is, for example, expressed by the following formula.
  • QILS ⁇ T ⁇ (a + b ⁇ PC)
  • ⁇ P -(K/VPC) ⁇ ⁇ T ⁇ (a + b ⁇ PC)
  • the ECU 20 measures the ⁇ P periodically in the respective fuel temperature range during the operation of the engine and calculates the values of the constants a and b in the respective fuel temperature range.
  • the ECU 20 further stores the values of a and b in the respective temperature range in the backup RAM and calculates the static fuel return amount QILS using the values of the constants a and b stored in the backup RAM in accordance with the fuel temperature.
  • the learning of the changes in the static fuel return amount is performed.
  • the fuel injection occurs in the period between the sampling points of PC1 0 and PC2 (Fig. 2), and the fuel feed does not occur in this period. Therefore, in the fuel cut operation of the engine in which the fuel injection is not performed, both the fuel feed and the fuel injection do not occur during the period between the sampling points of PC1 0 and PC2. Therefore, the value of DPC12 during the fuel cut operation can be used for ⁇ P when calculating the values of the constants a and b.
  • the ECU 20 measures the values of the pressure PC1 0 and the temperature THF1 and the pressure PC2 (Fig. 2).
  • the bulk modulus of elasticity K of the fuel is determined in accordance with the pressure PC1 0 and the temperature THF1.
  • Steps 803 through 813 are the operations substantially the same as steps 401 through 411 in Fig. 4.
  • the constants a and b used for calculating the static fuel return amount QILS are calculated at step 817 using the values of DPC.
  • DPC -(K/VPC) ⁇ ⁇ T ⁇ (a + b ⁇ PC1 0 ).
  • ⁇ T is an interval between the sampling points of PC1 0 and PC2 and ⁇ T ⁇ (a + b ⁇ PC1 0 ) corresponds to the static fuel return amount QILS.
  • the values of the constants a and b are obtained by solving the following simultaneous equations using the values of DPC measured in two successive execution of the operation.
  • DPC -(K/VPC) ⁇ ⁇ T ⁇ (a + b ⁇ PC1 0 )
  • DPC (i-1) -(K (i-1) /VPC) ⁇ ⁇ T (i-1) ⁇ (a + b ⁇ PC1 0(i-1)
  • the values with suffix (i-1) are the values measured or calculated when the operation is last performed.
  • the values of the constants a and b are obtained.
  • the ECU 20 stores the set of the calculated values of the constants a, b and the fuel temperature THF1 in the backup RAM at step 819 and renews the values of DPC (i-1) , K (i-1) , ⁇ T (i-1) , PC1 0(i-1) at step 821 in order to prepare for the next execution of the operation.
  • the values of the constants a and b associated with the respective fuel temperature are stored in the backup RAM of the ECU 20.
  • the values of a and b associated with the fuel temperature during the fuel cut operation are re-calculated and the values already stored in the backup RAM are replaced with the re-calculated values.
  • the values of the constants a and b stored in the backup RAM always correspond to the change in the clearances of the sliding parts.
  • the ECU 20 calculates the estimated values DPD and DPU of the pressure change in the common rail using the calculated value of QILS. Therefore, the calculated values DPD and DPU always correspond to the changes in the conditions of the engine and the fuel injection valves, and the failure of the fuel injection system can be determined more accurately using these values of DPD and DPU.
  • either of two types of the failure determining operation i.e., the determining operation based on the pressure change in the common rail during the fuel injection period (DPD, DPC12) and the determining operation based on the pressure change in the common rail during the fuel feed period (DPU, DPC21) is used.
  • These determining operations may be used separately as explained in the previous embodiments. However, if both of the determining operations are performed at the same time, it becomes possible to determine the types of the failure or identify the failed parts in the fuel injection system.
  • the failure occurs at somewhere upstream of the common rail 3 in the fuel injection system (for example, the leak in the portion upstream of the check valve 15, or the shortage of the fuel supplied to the fuel pump).
  • the ECU 20 performs both the determination based on the pressure change during the fuel injection period (Fig. 4) and the determination based on the pressure change during the fuel feed period, and determines that the present condition of the fuel injection system corresponds to one of the above (1) through (4).
  • Fig. 9 is a flowchart explaining the determining operation of the type of the failure in this embodiment. This operation is performed by a routine executed by the ECU 20 at predetermined intervals.
  • the failure type parameter FX is set to one of values 1, 2, 3 and 4 in accordance with the combination of the values of the failure flags XD and XU.
  • the value of the failure type parameter FX may be stored in the backup RAM of the ECU 20 to facilitate future inspection and maintenance.
  • the type of the failure in the fuel injection system is determined in accordance with the results of the failure determination by the operations in Figs. 4 and 5. Further, since both the determining operations in Figs. 4 and 5 are performed in each of the fuel injection cycle of the respective cylinders, i.e., two failure determining operations are performed in each cycle, the failure of the fuel injection system can be determined accurately.
  • the condition of the fuel injection system is classified in four types as explained above.
  • the type (1) in which the fuel injection amount becomes excessively large
  • the type (3) failure in which the fuel in the system leaks to the outside occurs.
  • the engine must be stopped immediately.
  • the type (2) failure is caused by the shortage of the fuel supplied to the fuel pump 5, it is not necessary to stop the engine immediately.
  • the shortage of the fuel supplied to the engine is caused by the clogging of the fuel filter 9b or the failure of the low pressure feed pump 9 and, since the fuel does not leak to the outside of the system in these cases, it is rather preferable to continue the engine operation in order to allow the driver to bring the automobile to the service garage.
  • the ECU 20 when the type of the failure is determined as the type (2), the ECU 20 further determines whether the failure is caused by the shortage of the fuel supply to the pump 5, or the leakage of the fuel in the fuel system.
  • the ECU 20 determines whether the fuel supply pressure PIN to the pump 5 is lower than a predetermined value PIN 0 (PIN 0 ⁇ 0).
  • PIN ⁇ PIN 0 it is determined that the failure is caused by the fuel leak such as from the high pressure fuel pump 5, and if PIN ⁇ PIN 0 , it is determined that the failure is caused by the shortage of the fuel supply to the pump 5.
  • Fig. 10 is a flowchart explaining the determining operation of the type of the failure in this embodiment. This operation is performed by a routine executed by the ECU 20 at predetermined intervals.
  • Fig. 10 is substantially the same as the flowchart in Fig. 9 except that step 907 in Fig. 9 is replaced by steps 1001 through 1007 in Fig. 10. Therefore, only steps 1001 through 1007 are explained hereinafter.
  • the ECU 20 read the fuel supply pressure PIN from the fuel supply pressure sensor 39 at step 1001 and determines whether PIN is lower than a predetermined negative pressure PIN 0 at step 1003. If PIN ⁇ PIN 0 , the ECU 20 sets the value of the failure type parameter FX to 21 at step 1005. If PIN ⁇ PIN 0 at step 1003, the ECU 20 sets the value of the parameter FX to 22 at step 1007.
  • the ECU 20 immediately stops the engine and, if the value of FX is 22, the ECU 20 only activates the alarm and continues the operation of the engine. Further, the value of the failure type parameter FX may be stored in the backup RAM to facilitate future inspection and maintenance.
  • the predetermined pressure PIN 0 in this embodiment is set at a negative pressure, i.e., a pressure lower than the atmospheric pressure in order to set the value of the parameter FX to 21 if the fuel leak from the fuel supply line 13 has occurred.
  • a negative pressure i.e., a pressure lower than the atmospheric pressure
  • the shortage of the fuel supply to the high pressure fuel pump 5 also occurs when the fuel leaks from the fuel supply line 13 even if the fuel filter 9b and the fuel pump 9 are normal. If the fuel leaks from the fuel supply line 13 to the outside, it is preferable to stop the engine immediately. However, when the fuel leak from the fuel supply line 13 occurs, the pressure in the line 13 does not become lower than the atmospheric pressure.
  • the fuel supply pressure PIN becomes lower than the atmospheric pressure only when the cause of the shortage of the fuel supply is other than the fuel leak from the supply line 13. Therefore, by setting the value of the parameter FX to 22 when the PIN is lower than the predetermined negative pressure PIN 0 , the parameter FX is set to 22 only when the fuel supply shortage, which does not involve the fuel leak to the outside, has occurred.
  • the failure type parameter FX is set to 22 only when the fuel leak to the outside has not occurred, and FX is set to either of 1, 3, 21 when the fuel leak to the outside has occurred. Therefore, it is easily determined from the value of the parameter FX whether it is necessary to immediately stop the engine.
  • fuel is supplied to a common rail from a high pressure fuel pump, and injected into the cylinders of an engine, from the common rail, via fuel injection valves.
  • An electronic control unit (ECU) of the engine controls the pressure in the common rail at a value determined by the operating conditions of the engine.
  • the ECU further detects the pressure and the temperature of the fuel in the common rail, and determines the bulk modulus of elasticity of the fuel based on the pressure and the temperature of the fuel.
  • the ECU calculates an estimated value of the pressure change in the common rail during the fuel injection period using the determined bulk modulus. If the difference between the estimated value of the pressure change and the pressure change actually measured during the fuel injection period is large, the ECU determines that the fuel injection system has failed.
  • the estimated value of the pressure change is calculated based on the bulk modulus of elasticity which is determined in accordance with the actual pressure and temperature of the fuel, the accurate estimated value is obtained even if the pressure and the temperature of the fuel in the common rail change over a very wide range.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Claims (13)

  1. Système d'injection de carburant destiné à un moteur
       à combustion interne comprenant :
    un réservoir (rampe d'alimentation commune) destiné à stocker du carburant sous pression,
    une soupape d'injection de carburant reliée au réservoir et injectant du carburant dans le réservoir jusque dans un moteur à combustion interne à un cadencement prédéterminé,
    une pompe à carburant destinée à alimenter le réservoir en carburant sous pression à un cadencement prédéterminé de manière à maintenir la pression du carburant dans le réservoir une valeur prédéterminée,
    un moyen de détection de pression destiné à détecter la pression du carburant dans le réservoir,
    un moyen de détection de module d'élasticité volumique destiné à détecter un module d'élasticité volumique du carburant dans le réservoir, et
    un moyen de détermination de défaillance destiné à déterminer si le système d'injection de carburant du moteur a été défaillant sur la base du module d'élasticité volumique détecté par le moyen de détection de module d'élasticité volumique et de la variation de pression du carburant dans le réservoir durant le fonctionnement du moteur.
  2. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 1, dans lequel ledit moyen de détection de module d'élasticité volumique calcule le module d'élasticité volumique du carburant dans le réservoir sur la base d'au moins l'une de la pression et de la température du carburant dans le réservoir.
  3. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 2, dans lequel ledit moyen de détermination de défaillance comprend un moyen de calcul de chute de pression destiné à calculer la chute de pression du carburant dans le réservoir durant une période d'injection de carburant de la soupape d'injection de carburant sur la base de la condition de fonctionnement du moteur et du module d'élasticité volumique détecté par le moyen de détection de module d'élasticité volumique, un moyen de détection de chute de pression réelle destiné à calculer la chute de pression réelle du carburant dans le réservoir durant la période d'injection de carburant de la soupape d'injection de carburant sur la base des pressions du carburant dans le réservoir détectées par le moyen de détection de pression avant et après l'injection de carburant, et un moyen de détermination de défaillance d'injection de carburant destiné à déterminer si le système d'injection de carburant a été défaillant sur la base de la différence entre la chute de pression calculée par le moyen de calcul de chute de pression et la chute de pression réelle.
  4. Système d'injection de carburant destiné à un moteur à combustion interne suivant la revendication 2, dans lequel ledit moyen de détermination de défaillance comprend un moyen de calcul d'augmentation de pression destiné à calculer l'augmentation de pression dans le carburant dans le réservoir durant une période d'alimentation en carburant de la pompe à carburant sur la base de la condition de fonctionnement du moteur et du module d'élasticité volumique détecté par le moyen de détection de module d'élasticité volumique, un moyen de détection d'augmentation de pression réelle destiné à calculer l'augmentation de pression réelle du carburant dans le réservoir durant la période d'alimentation en carburant de la pompe à carburant sur la base des pressions du carburant dans le réservoir détectées par le moyen de détection de pression avant et après l'alimentation en carburant et un moyen de détermination de défaillance d'alimentation en carburant destiné à déterminer si le système d'injection de carburant a été défaillant sur la base de la différence entre l'augmentation de la pression calculée par le moyen de calcul d'augmentation de pression et l'augmentation de pression réelle.
  5. Système d'injection de carburant destiné à un moteur à combustion interne suivant la revendication 3, dans lequel ledit moyen de calcul de chute de pression comprend en outre un moyen de calcul de quantité de retour du carburant destiné à calculer une quantité de retour du carburant qui est la quantité du carburant retourné depuis le réservoir (rampe d'alimentation commune) vers un réservoir à carburant durant la période d'injection de carburant sur la base d'au moins l'une de la pression de carburant, de la température de carburant, du régime du moteur et de la période d'ouverture de la soupape d'injection de carburant, et dans lequel ledit moyen de calcul de chute de pression calcule la chute de pression sur la base du module d'élasticité volumique, de la quantité de retour de carburant et d'une quantité d'injection de carburant déterminée par la condition de fonctionnement du moteur.
  6. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 4, dans lequel ledit moyen de calcul d'augmentation de pression comprend en outre un moyen de calcul de quantité de retour de carburant destiné à calculer une quantité de retour de carburant qui est la quantité du carburant retourné depuis le réservoir vers un réservoir à carburant durant la période d'alimentation en carburant de la pompe à carburant sur la base d'au moins l'une de la pression de carburant, de la température de carburant et du régime du moteur, et dans lequel ledit moyen de calcul de l'augmentation de pression calcule l'augmentation de pression sur la base du module d'élasticité volumique, de la quantité de retour de carburant et d'une quantité d'alimentation en carburant déterminée par la condition de fonctionnement du moteur.
  7. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 5, dans lequel ladite quantité dynamique de retour de carburant est une somme d'une quantité de retour de carburant qui est la quantité du carburant retourné depuis le réservoir vers le réservoir à carburant par l'opération d'injection de carburant de la soupape d'injection de carburant et d'une quantité statique de retour de carburant qui est la quantité du carburant retourné depuis le réservoir vers un réservoir à carburant indépendamment de l'opération d'injection de carburant de la soupape d'injection de carburant.
  8. Système d'injection de carburant destiné à un moteur
       à combustion interne selon la revendication 6, dans lequel ladite quantité de retour de carburant est une quantité de retour de carburant statique qui est la quantité du carburant retourné depuis le réservoir vers un réservoir à carburant indépendamment de l'opération d'injection de carburant de la soupape d'injection de carburant.
  9. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 7, dans lequel ledit moyen de calcul de quantité de retour de carburant comprend en outre un moyen d'apprentissage destiné à mesurer et à mémoriser la quantité du carburant retourné depuis le réservoir vers le réservoir à carburant durant la période au cours de laquelle à la fois l'injection de carburant et l'alimentation en carburant sont arrêtées, et dans lequel ledit moyen de calcul de quantité de retour de carburant calcule la quantité de retour de carburant statique sur la base de la valeur de la quantité du carburant mémorisée dans le moyen d'apprentissage.
  10. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 8, dans lequel ledit moyen de calcul de quantité de retour de carburant comprend en outre un moyen d'apprentissage destiné à mesurer et à mémoriser la quantité du carburant retourné depuis le réservoir vers réservoir à carburant durant la période au cours de laquelle à la fois l'injection du carburant et l'alimentation en carburant sont arrêtées, et dans lequel ledit moyen de calcul de quantité de retour de carburant calcule la quantité de retour de carburant statique sur la base de la valeur de la quantité du carburant mémorisée dans le moyen d'apprentissage.
  11. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 2, dans lequel ledit moyen de détermination de défaillance comprend :
    un moyen de calcul de chute de pression destiné à calculer la chute de pression du carburant dans le réservoir durant une période d'injection de carburant de la soupape d'injection de carburant sur la base de la condition de fonctionnement du moteur et du module d'élasticité volumique détecté par le moyen de détection de module d'élasticité volumique, un moyen de détection de chute de pression réelle destiné à calculer la chute de pression réelle du carburant dans le réservoir durant la période d'injection de carburant de la soupape d'injection de carburant sur la base des pressions du carburant dans le réservoir détectées par le moyen de détection de pression avant et après l'injection de carburant, et un moyen de détermination de défaillance d'injection de carburant destiné à déterminer si le système d'injection de carburant a été défaillant sur la base de la différence entre la chute de pression calculée et la chute de pression réelle, et
    un moyen de calcul d'augmentation de pression destiné à calculer une augmentation de pression du carburant dans le réservoir durant une période d'alimentation en carburant de la pompe à carburant sur la base de la condition de fonctionnement du moteur et du module d'élasticité volumique détecté par le moyen de détection de module d'élasticité volumique, un moyen de détection d'augmentation de pression réelle destiné à calculer l'augmentation de pression réelle du carburant dans le réservoir durant la période d'alimentation en carburant de la pompe à carburant sur la base des pressions du carburant dans le réservoir détectées par le moyen de détection de pression avant et après l'alimentation en carburant, et un moyen de détection de défaillance d'alimentation en carburant destiné à détecter si le système d'injection de carburant a été défaillant sur la base de la différence entre l'augmentation de pression calculée et l'augmentation de pression réelle.
  12. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 11, dans lequel ledit moyen de détermination de défaillance comprend en outre un moyen de détermination de type de défaillance destiné à déterminer le type de la défaillance du système d'injection de carburant sur la base des deux résultats de détermination du moyen de détermination de défaillance d'injection de carburant et du moyen de détermination de défaillance d'alimentation en carburant.
  13. Système d'injection de carburant destiné à un moteur à combustion interne selon la revendication 12, comprenant en outre un filtre de carburant disposé dans un circuit d'alimentation destiné à fournir du carburant vers la pompe à carburant et un moyen de détection de pression d'alimentation de carburant destiné à détecter la pression dans le circuit d'alimentation entre le filtre de carburant et la pompe, dans lequel ledit moyen de détermination de type de défaillance détermine au moins si un système d'alimentation en carburant comprenant la pompe à carburant et le circuit d'alimentation en amont de celle-ci a été défaillant sur la base des résultats de détermination du moyen de détermination de défaillance d'injection de carburant et du moyen de détermination de défaillance d'alimentation en carburant et dans lequel ledit moyen de détermination de type de défaillance, lorsqu'il est déterminé que le système d'alimentation en carburant a été défaillant, détermine en outre que la défaillance du système d'alimentation en carburant est provoquée par le manque de carburant fourni à la pompe à carburant si la pression détectée par le moyen de détection de pression d'alimentation en carburant est inférieure à une valeur prédéterminée.
EP19980102970 1997-02-21 1998-02-20 Système d'injection de combustible pour moteur à combustion interne Expired - Lifetime EP0860601B1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP3799697 1997-02-21
JP3799697 1997-02-21
JP37996/97 1997-02-21
JP20060197 1997-07-25
JP200601/97 1997-07-25
JP20060197A JP3796912B2 (ja) 1997-02-21 1997-07-25 内燃機関の燃料噴射装置

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EP0860601A2 EP0860601A2 (fr) 1998-08-26
EP0860601A3 EP0860601A3 (fr) 2000-01-19
EP0860601B1 true EP0860601B1 (fr) 2002-11-27

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EP0860601A2 (fr) 1998-08-26
EP0860601A3 (fr) 2000-01-19
JP3796912B2 (ja) 2006-07-12
DE69809614D1 (de) 2003-01-09
JPH10299557A (ja) 1998-11-10
DE69809614T2 (de) 2003-04-10

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