DE10301956A1 - Fuel injection system for an engine has four injection valves from common rail fuel line and electronic control of start up injection - Google Patents

Abstract

A collective fuel injection device for an engine comprises a high-pressure pump (7), a common rail fuel feed (5) and an injection control ECU (10) which detects a time before a given engine revolution on starting and a rate of pressure increase. Injection is adjusted for the next starting if the given start time is exceeded. An Independent claim is also included for a system as above having an additional starting correction unit.

Description

The present invention relates to a collection Fuel injection device and in particular on a Improving the stability of an internal combustion engine with a Common rail fuel injector made by a High-pressure pump ejected high-pressure fuel in one Common rail collects and the collected high pressure fuel over a fuel injection valve to the internal combustion engine injects.

As a common rail fuel injector for one A diesel engine's fuel injection system is one Collective fuel injector known. This device has a high pressure pump that is driven by the torque of the crankshaft the diesel engine is driven to the one Fuel tank sucked fuel with pressure too act upon and expel, and a common rail acting as a Intermediate tank of high pressure fuel is used, from this High pressure pump is ejected.

In this collective fuel injector one on the High pressure pump attached adjustment valve based a control signal from an electronic control unit (ECU) controlled to by the high pressure pump to a fuel pipe amount of high-pressure fuel led to the common rail adjust. Then the common rail pressure in this way and Controlled to a desired injection pressure.

In the conventional device, a change in Ejecting from the high pressure pump due to design or Changes in the operation of the adjustment solenoid valves, even if the adjustment solenoid valves have the same shape exhibit. Especially when the engine is started, cause the changes from the adjustment solenoid valves, namely changes in the high pressure pumps, changes in the Injection quantity or the injection pressure of the fuel that from a fuel injector to the diesel engine is injected. As a result, this poses a problem a change in the starting power of the engine.

The present invention has been made in view of such drawbacks devised. It is therefore the object of the present invention to provide a collective fuel injector that is a Ensure the desired starting ability of an internal combustion engine can without increasing emissions of harmful exhaust gases regardless of changes in high pressure pumps.

According to the present invention, a collection Fuel injector a high pressure pump, a common Rail, fuel injectors and an exhaust control unit. When an engine is started, it detects the Ejection control unit that time that has passed before the Speed of the engine reaches a predetermined speed, and it detects a pressure increase characteristic of the Fuel pressure. When the elapsed time is a predetermined one Exceeds the start time, then increases or decreases the Discharge control unit the discharge at the next Engine starting procedure according to the Pressure increase characteristic.

Alternatively, if a predetermined time after the start of the Engine has passed, then determines the Ejection control unit whether the engine speed is a predetermined speed reached. The exhaust control unit corrects the output at the next one Engine starting in response to the actual one Fuel pressure when the predetermined time has passed and an actual speed of the engine is compared to a predetermined speed of the engine.

The above task and other features and Advantages of the present invention will become apparent from the following detailed description with reference to the accompanying Drawings can be seen.

Fig. 1 is a schematic view of a common rail Krafstoffeinspritzvorrichtung shows the first embodiment according to the present invention;

Fig. 2 shows a schematic view of a control system shown in Fig. 1;

Fig. 3 shows a schematic view of a flow control valve of a high pressure pump shown in Fig. 1, Fig. 3 (a) shows a cross sectional view of the flow control valve, and Fig. 3 (b) shows an enlarged view of an inlet port when it is from one direction B is viewed in Figure 3 (a);

Fig. 4 shows a graphical representation of the drive characteristic of the length valve shown in Fig. 3;

FIG. 5 shows a flowchart of pre-processing of a high-pressure pump control start-up performed by an ECU shown in FIG. 1;

Fig. 6 shows a flowchart of a starting process of a high pressure pump control according to the first embodiment of the present invention;

Fig. 7 is a flow chart showing a process of a Star high-pressure pump control system according to the second embodiment of the present invention; and

Fig. 8 is a flow chart showing the control of a high-pressure pump according to the third embodiment of the present invention.

Preferred embodiments of the present invention are with reference to various embodiments described in which a collection Fuel injector as a common rail Fuel injector of a diesel engine is used.

First embodiment

As shown in Fig. 1, a common rail fuel injection device has a high pressure pump 7 for sucking fuel from a fuel tank 6 , a common rail 5 , which is in the form of an intermediate tank for collecting high pressure fuel, which from of the high pressure pump 7 , a plurality of fuel injectors (injectors) 1 to 4 , each attached to a respective cylinder of a multi-cylinder (4 cylinder as shown in FIG. 1) diesel engine (engine) to high pressure fuel in the common rail 5 , feed and inject into the combustion chamber of the cylinder, a fuel pressure detection unit 81 for detecting the fuel pressure of the high pressure fuel collected in the common rail 5 , and a discharge control unit 10 for controlling the discharge operation of the high pressure pump 7 in response to a drive z detected by a drive state detection sensor group 70 and a fuel pressure detected by a fuel pressure detection unit 81 . Here, this control unit 10 is an electronic control unit (ECU) for electronically controlling not only the high-pressure pump 7 but also the plurality of injection devices 1 to 4 .

Here, the engine is started by rotating the flywheel (not shown) of the engine at a speed greater than a minimum speed required to start the engine by a starting device (not shown) by the electric power a battery is turned. The power supply to the starting device is started by the ECU 10 when a vehicle occupant switches an ignition switch from an OFF position to a starting position (ST position), namely, when a starter ON signal is turned on (ON).

Each injector of the plurality (in the present embodiment example 4) injectors 1 to 4 is attached to the combustion chamber of each cylinder of the engine and injects the high-pressure fuel into the respective combustion chamber of the engine a. Then, the amount of fuel injected into the engine from the respective injectors 1 to 4 and a fuel injection timing are determined by electronically controlling the power supply to the respective injection period control solenoid valves (injection period changing units) 11 to 14 as actuators and stopping the power supply by the ECU 10 .

The common rail 5 is designed as an intermediate container for collecting high pressure fuel under a comparatively high pressure (100 to 1000 times the atmospheric pressure as a common rail pressure), and it is connected to the various injectors 1 to 4 via a high pressure pipe 8 connected. Here, the various injectors 1 to 4 , the common rail 5 and a fuel return pipe 9 from the high pressure pump 7 to the fuel tank 6 are constructed such that they also release a pressure from a pressure limiting device 15 , so that the common rail pressure in the Common rail 5 does not exceed a collective limit pressure.

The high pressure pump 7 has a feed pump in which a feed pump (not shown) is installed, which rotates according to the rotation of the crankshaft (not shown) of the engine, around the fuel in the fuel tank 6 through a fuel pipe 17 with a fuel filter 16 arranged therein to suck, and which pressurizes the fuel drawn in by the feed pump and forwards the high-pressure fuel. This high pressure pump 7 is equipped with a quantity control solenoid valve 19 as an exhaust adjustment solenoid valve.

This quantity control solenoid valve (injection pressure control solenoid valve) 19 is an injection pressure change unit that is electronically controlled by a control signal from the ECU 10 to adjust the high pressure fuel amount supplied to the common rail 5 through the fuel pipe 18 from the high pressure pump 7 , thereby to set an injection pressure for injecting the fuel to change in the combustion chambers of the engine from the respective injectors 1 to 4 .

The ECU 10 is composed of a CPU for performing control processing and calculation processing, a ROM for storing various kinds of control programs and data, a RAM for storing input data, an input circuit, a discharge circuit, a power supply circuit, and an injector drive circuit (EDU) 20 . This ECU 10 controls the injection pressure control solenoid valve 19 of the high pressure pump 7 and the injection period control solenoid valves 11 to 14 of the injectors 1 to 4 according to the driving state or the like of the engine detected by the driving state detection sensor group 70 .

The EDU 20 receives a control signal (e.g., a control pulse signal) that is output from the ECU 10 to increase the voltage of a battery (not shown) so that a valve opens or closes in response to one Fuel injection timing (valve opening timing) and the amount of fuel (injection period) calculated by the ECU 10 so as to control the power supply or the power supply stop by the various injection period control solenoid valves 11 to 14 of the various injectors 1 to 4 .

The drive state detection sensor group 70 for inputting signals representative of the drive state of the engine includes a speed sensor 71 for detecting the speed of the engine, an accelerator position sensor 72 for detecting the depression amount of an accelerator pedal (accelerator position), and an intake air temperature sensor 73 for detecting the temperature of an intake air is sucked by the engine, a cooling water temperature sensor 75 for detecting the cooling water temperature of the engine and a crank angle sensor 77 for detecting the rotation angle of the crankshaft of the engine and the rotational speed of the engine.

Furthermore, ECU 10 is connected to the fuel pressure sensor 81 for detecting the fuel pressure (injection pressure, common rail pressure) of the high pressure fuel collected in the common rail 5 and a fuel temperature sensor (fuel temperature detection unit) 82 for detecting the temperature of the fuel in the return pipe 9 .

Here, the ECU 10 calculates the fuel injection timing (valve opening timing) of the injectors 1 to 4 and the discharge from the high pressure pump 7 (fuel delivery period) based on signals from the crank angle sensor 77 such as a crank angle speed pulse and a camshaft speed pulse when the engine is stationary. and controls a timing to supply current through the injection pressure control solenoid valve 19 of the high pressure pump 7 so as to keep the common rail pressure at the most appropriate injection pressure (target pressure).

Then, the ECU 10 calculates the fuel injection amount from values measured by the speed sensor 71 , the accelerator position sensor 72 , the cooling water temperature sensor 75, or the fuel temperature sensor 82 . Then, in order to obtain the calculated fuel injection amount, the ECU 10 drives the injection period control solenoid valves 11 to 14 of the various injectors 1 to 4 by an injector energization time command (value) calculated from the fuel pressure in the common rail 5 for the respective driving state, thereby thereby to drive the engine.

The ECU 10 is further configured so that when the driver starts supplying power to the starting device for the purpose of starting the engine to crank the engine crankshaft at a speed greater than a required minimum speed, the ECU 10 calculates an injection start pressure (a target common rail pressure in the period of the starting process = a target pressure) that is most suitable for starting the engine, for example according to an engine cooling water temperature (TW) detected by the cooling water temperature sensor 25 or a correction quantity that is obtained by adding a starter-ON duration to the engine cooling water temperature (TW) (injector start pressure determination unit) and inhibits the injector energization time command (injector opening command) to the various injectors 1 to 4 until the common rail pressure (actual common rail pressure) ) detected by the fuel pressure sensor 81, has risen above the set pressure. Here, depending on a target starting time to ensure the desired starting ability of the engine, it is not necessary to construct the ECU 10 so that the ECU 10 prohibits the above-mentioned injector opening command.

In this regard, the ECU 10 in the present embodiment is configured so that the ECU 10 prohibits the injector opening command until the actual common rail pressure has increased beyond a predetermined pressure. This can shorten a time from the start of the injection process of the fuel to the realization of an effective combustion (complete combustion).

Here, if the common rail fuel injection device having the structure described above maintains the predetermined pressure after the common rail pressure has become the target pressure, a change in the start time is not caused by changes in the common rail fuel injection devices even if the operating characteristics of the fuel injection devices differ slightly from device to device. However, the target pressure at start is set to that pressure which is less than a common rail pressure during a stationary drive mode, and during the starting process, there is a transition state in which the common rail pressure reaches the target pressure and then increases , For this reason, there is a possibility that the transition characteristic of the common rail pressure during the starting process is impaired by a change under the common rail fuel injection devices, in particular a change under the high pressure pumps 7 for guiding the high pressure fuel, so that changes in the Start time between the actual internal combustion engines are caused by the common rail fuel injectors with respect to the target start page of the engine, and thus the target start time becomes unsatisfactory.

On the other hand, there is also a method for preventing the Injector opening command until the common rail Pressure from the target start pressure to the common rail pressure during of the stationary drive mode has increased. However extended this procedure the unused time of the starting process, before the complete combustion of the fuel in the Engine has entered. This procedure extends the Starting time for cranking the engine, that time that from the point in time when the driver of the vehicle Power to the starter starts to burn to complete what makes it difficult to achieve a desired one To ensure starting assets. In some cases, there is Possibility that this procedure uses battery power increases so that the battery discharges and it becomes difficult to start the engine.

Thus, in the present exemplary embodiment, a collective fuel injection device is provided which has the following features and can thus ensure a desired starting capacity of the internal combustion engine regardless of changes in the high-pressure pumps 7 .

A change in the transition characteristic of the common rail pressure Pc caused by changes in the high pressure pumps 7 (see FIG. 6 (b)), namely a change in the output of the high pressure pump 7 can be eliminated by having a high pressure pump control start processing S600 ( FIG . 5, Fig. 6 is added) to perform an ejection correction.

In this high pressure pump start control processing S600, correction of a drive amount for driving the quantity control valve 19 as the discharge adjustment solenoid valve of the high pressure pump 7 is performed by the ECU 10 . In this regard, the change among the quantity control valves 19 also causes a change in the output with respect to the same drive amount, so that the above-mentioned correction of the output of the high pressure pump 7 cannot be performed appropriately at the initial start-up, but that it causes an output to be carried out on the next one Starting process is suitable. In this way, the high-pressure pump start control processing S600 is continuously performed at every start-up to optimize the discharge, thereby ensuring the predetermined starting ability.

The high pressure pump start control processing S600 of one embodiment is described below with reference to FIGS. 5 and 6. FIG. 5 shows a flowchart of preprocessing of the high pressure pump start control processing S600 that is executed by the ECU 10 shown in FIG. 1. FIG. 6 is a flowchart showing the high-pressure pump start control processing.

When the engine is to be started, the vehicle occupant first turns the ignition switch from the OFF position to the ON position in order to rotate the starter motor by means of an electric current from the battery and at the same time to turn a pinion driven by an overturning clutch with a ring gear engage the outer periphery of the flywheel, which is directly connected to the crankshaft of the engine to rotate the flywheel. In this way, the crankshaft is rotated to vertically move a piston in the cylinder of the engine so as to suck air into the cylinder through an intake pipe. On the other hand, the high pressure pump 7 also pressurizes the fuel sucked from the fuel tank 6 by the rotation of the crankshaft of the engine to increase the fuel pressure Pc in the common rail 5 .

As shown in FIG. 5 at step S501, it is determined whether the ignition switch has been switched to the ST position and is the starter-on signal generated by the contact of a movable contact with a fixed contact of the starting device then in the on state. This serves to detect a start of the power supply to the starting device. If the starter ON signal is in the OFF state, the processing is ended. In contrast, if the starter signal is in the ON state, then the processing proceeds to the high pressure pump start control processing at step S600.

In this regard, in the state of a starter drive state in which the starter ON signal is determined to be ON, the engine is cranked at a speed greater than a minimum speed (e.g., 400 RPM) required to start the engine Engine is required so that the high pressure pump 7 is driven by the rotation of the crankshaft, and a current passes through the injection pressure control solenoid valve 19 to gradually increase the fuel pressure in the common rail 5 (= fuel pressure in the rail) Pc.

Next, in the high pressure pump start control processing S600, control processing from S601 to S607 is performed to correct the predetermined drive amount of the injection pressure control solenoid valve 19 at the next starting operation if a time elapsed until a predetermined engine speed is reached (idle speed in the present embodiment) is, the target start time exceeds.

As shown in FIG. 6, the driving amount D of the injection pressure control solenoid valve 19 of the high pressure pump 7 is set to a predetermined value D1 at S601. Here, in the initial starting process, this value D1 is an initial fixed value, namely a predetermined value, which is fixed upon delivery from a factory, and in the subsequent starting process, the initially fixed value (which is not subject to correction) or by means of a Correction refreshed value depending on the history of the correction used as the value D1. The injection pressure control solenoid valve 19 is driven and controlled by the ECU 10 based on this predetermined value D1 to adjust the discharge of the high pressure fuel discharged from the high pressure pump 7 . Then, the fuel pressure in the common rail 5 is gradually increased in response to this discharge.

In order to simplify the description here, it is assumed that the initially set value as the predetermined value D1 is entered with respect to the drive amount D, and the Control processing according to S602 is described.

At S602, a time Ts that has elapsed before the engine speed N reaches a predetermined speed (idle speed in the present embodiment) Ns is detected by the speed sensor 71 as the drive state detection sensor group 70 ( FIG. 6 (a)), and the pressure increase characteristic of the common rail pressure Pc in the common rail 5 is detected by the fuel pressure sensor 81 as a pressure detection unit, and thus a fuel pressure increase per unit time (ΔPc / ΔT) is calculated by the ECU 10 . In this regard, (a) at step S602, here shows a schematic illustration of the so-called engine speed characteristic with a rapid increase in the starting process, and it provides a graphical representation of the time Ts from the starting process of the starting device (for example, a time when the starter signal is ON State) about the state of a rapid increase in engine speed up to the point in time when the engine speed N returns to the idling speed Ns. (b) at S602 is a schematic illustration of a pressure increase characteristic of the common rail pressure Pc at the start-up, and the characteristic shown by a broken line and a two-dot chain line represents the case where (ΔPc / ΔT) is large, and the case where (ΔPc / ΔT) is small in terms of the pressure increase characteristic shown by a solid line.

Here, factors of changes caused by the changes under the injection pressure control solenoid valves 19 for adjusting the discharge of the high pressure fuel carried by the common rail 5 will be described below with reference to FIG. 3 and FIG. 4. FIG. 3 shows a schematic illustration of the quantity control valve of the high-pressure pump 7 shown in FIG. 1. FIG. 3 (a) shows a cross sectional view of the flow control valve, and FIG. 3 (b) shows an enlarged view of an inlet port when viewed in a direction B in FIG. 3 (a). FIG. 4 shows a graphic representation of a drive characteristic of the quantity control valve shown in FIG. 3.

As shown in FIG. 3 (a), the Einspritzdrucksteuersolenoidventil 19 in the present embodiment, a well-known quantity control valve, and it has b an electromagnet driving portion including a movable core 19a, a stator core 19, which together with the movable core 19 a forms a magnetic circuit, and an electromagnetic coil 19 c, which then generates an electromagnetic force when a current is supplied to it, a valve body 19 d, a valve element 19 e which is slidably received in the valve body 19 d and together with the a movable core 19 can reciprocate, and a valve portion having a bias spring 19f for biasing the valve element 19 e to the side of the movable core 19 a. Here, this solenoid valve 19 changes the opening area A of the inlet port (see Fig. 3 (b)) by means of an ON-OFF control (ON-OFF solenoid valve), or it may be a linear solenoid valve in which the opening area A of the inlet port is through a position in the axial direction of the valve element 19 e is changed, which moves in the axial direction in the valve body 19 d. In the ON-OFF solenoid valve, this opening area A can be changed by means of a pulse duration control in which a valve opening / closing period is changed by the ECU. On the other hand, in the linear solenoid valve, the opening area A can be changed by changing an average drive current by the pulse duration control ( Fig. 4).

In this regard, it is assumed that the injection pressure control solenoid valve 19 is a solenoid valve, and the following description is made accordingly.

Similar to the drive characteristic of the injection pressure control solenoid valve 19 shown in FIG. 4, in which a horizontal axis represents a drive amount D and a vertical axis represents the opening area A of the intake port, namely, the injection pressure control solenoid valve 19 , the opening area A, that is, the discharge of, decreases High-pressure pump 7 decreases as the amount of drive increases. On the other hand, the opening area A of the injection pressure control solenoid valve 19 increases , and the output of the high pressure pump 7 increases as the driving amount becomes smaller.

Factors that cause a change in the ejection of high-pressure pump 7 with respect to the Einspritzdrucksteuersolenoidventils 19 include, in the solenoid driving section, the effect of an attractive force Fc, which is caused by the change of the solenoid coils 19 c, which generate the electromagnetic force, and the valve portion, the effect a spring constant K of the biasing spring for determining the position of the valve element in the axial direction by the balance between the biasing force and the attraction force in response to the electromagnetic force generated by the solenoid coil 19 , the effect of its fixed load Fs, and an effect that is produced is caused within a design tolerance, such as the effect of the valve opening position of the valve element together with the movable core which is driven by the attractive force. For this reason, the output of the high pressure pump 7 is changed by changes in the injection pressure control solenoid valves 19 even if the drive amount output by the ECU 10 remains the same.

In contrast, in the embodiment of the present invention in the case where the predetermined Starting assets cannot be guaranteed or otherwise said in the case where the time Ts which is up to Starting process elapses, the target time Ta exceeds that carried out the following correction.

At S603, it is determined whether the time Ts measured at S602 is less than the target time Ta (for example 20 seconds). If the time Ts is less than the target time Ta, then the Control processing ended. If the time is Ts in contrast for this purpose exceeds the target time Ta, then the Processing continues to S604, in which a correction according to Pressure increase characteristic of the common rail pressure Pc is carried out. Here are S604 and S606 steps to determine the pressure increase characteristic.

At S604, it is determined whether the pressure increase characteristic ΔPc / ΔT (actual value of ΔPC / ΔT) calculated at S602 was larger than a predetermined upper one Boost limit (upper limit) UL on the side of one upper limit of a range of the pressure increase characteristic ΔPc / ΔT (permissible range of ΔPc / ΔT) in which the Based on an experiment or the like was that the predetermined starting assets are guaranteed can. If the actual value ΔPc / ΔT is larger than that upper limit UL, then the drive amount D (Pulse duration ratio through the pulse duration control) at S605 increases (D1 = D1 + ΔD), and the control processing becomes completed. In contrast, if the actual value ΔPc / ΔT is less than the upper limit UL, then the Processing to S606 further.

At S606, it is determined whether the actual value ΔPc / ΔT is smaller is as a predetermined lower increase limit (lower Limit value) LL on a lower limit side of the permissible Range of ΔPc / ΔT. If the actual value of ΔPc / ΔT is less than the lower limit LL, then the Drive amount D (pulse duration ratio) reduced in S607 (D1 = D1 - ΔD), and control processing is ended. If in In contrast, the actual value ΔPc / ΔT is larger than that lower limit LL, then the control processing completed.

If the actual value of DPc / ΔT is larger than the upper limit value UL (for example, a dashed line at S602 (b) in the characteristic shown in FIG. 6) according to the comparison and determination of the pressure increase characteristic (the actual value of ΔPc / ΔT) in the above steps S604 and S606 with respect to the lower limit by making a correction (D1 = D1 + ΔD) so as to increase the driving amount D of the injection pressure control solenoid valve 19 for adjusting the discharge, the discharge can be performed at the next starting operation be reduced. On the other hand, if the actual value of ΔPc / ΔT is smaller than the lower limit (for example, a characteristic shown by a two-dot chain line at S602 (b) in Fig. 6 by making a correction (D1 = D1 - ΔD) so as to drive amount D of the injection pressure control solenoid valve 19 for adjusting the discharge, the discharge can be increased at the next starting operation. The drive amount D corrected as described above is stored in a memory as a learning value so that it can be used next time (S601 at the next engine start).

In this way, it is possible to carry out a correction of the drive amount D during the next engine starting process, namely to continuously carry out a learning control for each starting process until the time Ts becomes smaller than the target starting time Ta, until the predetermined starting capacity is guaranteed , It is thus possible to ensure the predetermined starting ability of the internal combustion engine regardless of the change between the high-pressure pumps 7 .

Second embodiment

In the second embodiment shown in FIG. 7, it is determined whether the speed N1 reached (actual speed of the internal combustion engine) reaches a target speed of the internal combustion engine Na when a predetermined time T1 has passed after the start. Fig. 7 is a flowchart showing the high-pressure pump start control processing 700th The high-pressure pump start control shown in Fig. 7, the control processing is used according to the collecting fuel injection device in the first embodiment (Fig. 1 and Fig. 2), and when the pre-processing at this high-pressure pump start control as in the first embodiment, control processing for Detection of a starting operation by the starting detection unit for supplying a current to the starting device is performed (S501 in FIG. 5).

As shown in FIG. 7, in the high pressure pump start control processing 700, the control processings at S601 and S702 to S706 are performed.

The drive amount D of the injection pressure control solenoid valve 19 of the high pressure pump 7 is set as the predetermined value D1 by the control processing at S601 ( Fig. 6), and then the actual speed of the engine N1 is detected at S702 when the predetermined time T1 after the engine starts has passed ((a) in FIG. 7). Further, when the predetermined time T1 has passed, the fuel pressure (actual fuel pressure) Pc1 of the common rail pressure Pc reached is detected by the fuel pressure sensor 81 .

By detecting a start of power to the Starting device by capturing a timing if that Starter on signal from the OFF state to the ON state changed, the timing is recorded in which the Drive process of the starter was started to the Start internal combustion engine.

At S703, it is determined whether the actual one detected at S702 Speed of the internal combustion engine N1 a predetermined speed the internal combustion engine (target engine speed) Na (for example, exceeds 400 rpm). If the actual Speed N1 exceeds the predetermined speed Na, then the tax processing is ended. In contrast, if the actual speed N1 does not exceed the predetermined speed Na control processing proceeds to S704 further.

At S704, in order to make a correction to ensure the predetermined starting ability, the actual engine speed N1 and the actual fuel pressure Pc1 are stored in the ECU 10 as current data indicating the starting ability of the engine at the time when a predetermined time T1 has passed, and the processing proceeds to S705.

At S705 and S706, the initial value D1 of the drive amount D is corrected to a predetermined initial value (target drive amount) Da suitable for the high pressure pump 7 attached to the engine (D1 is replaced with Da) using the actual speed N1 and the actual fuel pressure Pc1 with reference to data stored in advance for the correction. At S705, a target fuel pressure Pca is determined so that the actual speed N1 becomes the target speed of the engine Na at the next start-up using the actual speed N1 and the actual fuel pressure Pc1. At S701, the target drive amount Da is determined by the target fuel pressure Pca at the next starting operation.

More specifically, at S705, the target fuel pressure Pca is determined according to the actual speed N1, as shown in the graph at S705, from a correlation of the fuel pressure Pc and the speed N1 at the start. Here, a method for calculating the target fuel pressure Pca may be any method using an image or a calculation formula. The map may be any one-dimensional map of the actual engine speed N1, a two-dimensional map of the actual engine speed N1 and the fuel temperature TF detected by the fuel temperature sensor 81 , and a three-dimensional map of the actual engine speed N1, the actual fuel pressure Pca and the fuel temperature TF. Furthermore, the calculation formula can be any function such as Pca = f (N1) with the actual speed N1 as a variable, a function Pca = f (N1, t) with the actual speed N1 and the fuel temperature TF as a variable and a function Pca = f (N1, Pc1, TF) with the actual speed N1, the actual fuel pressure Pc1 and the fuel temperature TF as variables.

Compared to a method for determining the target Fuel pressure Pca exclusively from the actual Speed N1 can be the method for calculating the target Fuel pressure Pca with further consideration of the effect the fuel temperature TF the calculation accuracy improve, and the method for calculating the target Fuel pressure Pca with further consideration of the Fuel temperature and actual fuel pressure Pc1, which is generated by the fuel temperature, can Further improve calculation accuracy. By calculating the Target pressure Pca taking into account the fuel temperature TF it is possible to also take off the starting ability when starting ensure low temperature.

At S706, the correlation between the fuel pressure Pc and the drive amount (pulse duration ratio) D at the start, as shown in the graph at S706, the target drive amount (target pulse duration ratio) Da determined according to the target fuel pressure Pca.

In this regard, the method for calculating this target Drive amount Since a procedure using an illustration such as a one-dimensional map of the target Fuel pressure Pca, a two-dimensional map of the target Fuel pressure Pca and the fuel temperature TF, one three-dimensional mapping of the target fuel pressure Pca, one fixed drive amount D1 at the start and the Fuel temperature using TF or a method a calculation formula such as a function Da = f (Pca) with the target fuel pressure Pca as a variable, one Function Da = f (Pca, t) with the target fuel pressure Pca and the Fuel temperature TW as variables and a function Da = f (Pca, D1, t) with the target fuel pressure Pca, the fixed Drive amount D1 and the fuel temperature TW as variables.

In this way, the output of the high pressure pump can be corrected to a suitable output for the internal combustion engine with the high pressure pump 7 attached to it at the next starting operation, and thus the effect of the changes among the high pressure pumps 7 (more specifically, the changes in the output among the Injection pressure control quantity control valves 19 ) can be reduced in terms of starting capacity. As a result, it is possible to guarantee a predetermined starting capital. For example, it is possible to ensure the predetermined starting capacity by checking the target drive amount Da for each starting process and correcting the drive amount D1 for starting.

The S700 high-pressure pump start control processing works Control processing at S702 and S703 as one Starting capital determination unit, which determines whether the actual speed N1 reaches the target speed Na when the Internal combustion engine is started and then a predetermined one Time T1 has passed. That way it's with a method for determining the starting assets possible, the To determine starting ability, even if the starting process is not is complete, even in a transitional state during the startup process such as in the Drive state of the internal combustion engine, in which the speed of the Engine is comparatively low, namely right after the start of the engine. The starting asset determination unit can determine or it can be a predictive determination meet whether the predetermined starting assets are guaranteed can by the actual speed N1 at that time, when the predetermined time T1 has passed, with the target Speed Na is compared and determined from this.

The starting ability determination is performed using the drive state detection sensor group 70 and an engine start command detection. This enables the starting ability determination unit to easily detect the starting process of the internal combustion engine and thus to reliably compare the actual speed N1 with the target speed Na even if the predetermined time T1 that has elapsed after the starting process is shortened to a certain extent , Thus, using the starting ability determination unit, it is possible to make a determination to ensure the starting ability, even in the transition state immediately after the engine start.

The control processings at S704 to S706 constitute a discharge correcting unit for correcting the discharge D1 at the next starting operation in response to the actual fuel pressure Pc1 and the actual speed N1 at the predetermined elapsed time T1. With this discharge correction unit, it is possible to improve the starting ability and thus to ensure the predetermined starting ability regardless of the changes among the high-pressure pumps 7 .

In this regard, the correction of the output D1 is performed by the output correction unit in the case where the starting ability determination unit determines that the actual speed N1 does not reach the target speed Na. For this reason, it is possible to reduce the load of the discharge correction unit, namely the load of the ECU, compared to the case where the correction of the discharge is performed regardless of whether the actual speed N1 is larger or smaller than the target speed Na 10th

Here, the target speed Na any speed of the Internal combustion engine, provided that it is within an area of the speeds, which during the drive state of the Start of the start process up to the completion of the start process occur.

Third embodiment

In the third exemplary embodiment according to FIG. 8, a cylinder discrimination unit for distinguishing the cylinders of the internal combustion engine and a control unit are provided which can regulate the output D for each cylinder. Fig. 8 is a flowchart showing the high-pressure pump according to the present embodiment.

The cylinder discrimination unit has the crank angle sensor 77 and the speed sensor 71 ( FIG. 2). For example, the cylinder discriminating unit is a well-known unit in which one signal per revolution of the high pressure pump 7 is sent by the crank angle sensor 77 , and a plurality of signals (for example, 60 in the case of four cylinders, which is a multiple of four) become per revolution the high pressure pump 7 sent by the speed sensor 71 . The ECU 10 receives these signals and determines a specific cam phase 8 (not shown) corresponding to a specific cylinder of the high pressure pump 7 .

The control unit is a well-known control unit of the discharge D according to the cylinder, which by the Cylinder discrimination unit was distinguished.

As shown in FIG. 8, it is determined at S801 whether the cylinder can be discriminated by the cylinder discrimination unit. More specifically, it is determined whether the signal that is output at least from the crank angle sensor 77 or the speed sensor 71 is greater than a predetermined signal output (detectable threshold value). If the signal output is greater than the detectable threshold, then it is determined that the cylinder can be discriminated, and the processing proceeds to S802. In contrast, processing proceeds to S700 when the signal output is less than the detectable threshold. In this regard, a determination criterion of whether the cylinder can be distinguished is not limited to the threshold value mentioned above, but a lower limit speed of the internal combustion engine can be provided, at which these signal outputs can be detected.

At S802, the relationship between that by the Cylinder determination unit determined cylinder of the Internal combustion engine and the specific cam phase the cylinder, the output D is controlled according to the cylinder.

On the other hand, at S700, the high pressure pump start control described in the second embodiment is performed. That is, the predetermined driving amount D1 is input as the driving amount D in the starting operation, and the discharge setting of the high pressure pump 7 in response to the driving amount D1 is performed, and the target driving amount Da in the next starting operation is determined by the starting ability determination unit and the discharge correction unit certainly. Then processing proceeds to S802.

If it is determined by the start determination unit that the actual rotation speed N1 reaches the target rotation speed Na, then the exhaust correction unit does not make a correction, but the control unit controls the exhaust according to the cylinder. In this way, it is possible to perform learning control to make a correction for the effects caused by the changes under the high pressure pumps 7 in the next starting operation until the starting ability determination unit determines that the predetermined starting ability is ensured.

If it is further determined that the actual speed N1 reaches the target speed Na and that the predetermined one Starting assets are guaranteed, then it is possible to get one Correction not for the next start process but for Improve starting assets during the starting process perform. For example, it is possible in an effective manner the starting ability in the range of the speed of the Improve internal combustion engine, the target speed Na in response to the set value the target speed Na. In this regard, it is possible to be more effective Way, the starting ability in the range of speed To improve the internal combustion engine, the target speed of the Internal combustion engine exceeds Na, namely through the Regulation, even if the starting assets determination unit is not determines that the predetermined starting ability is guaranteed.

Here, in the present embodiment, the target rotation speed Na is set to a value smaller than a lower limit rotation speed Nj ((a) at S702 in Fig. 7) at which the cylinder can be discriminated by the cylinder discrimination unit. In this way, it is possible to perform the learning control for making a correction in the next starting operation and the control for making a correction for improving the starting ability during the starting operation, and thus effectively ensuring the predetermined starting ability. In this regard, it is desirable that the target speed Na is close to the lower limit speed.

A collective fuel injector has a high pressure pump ( 7 ), a common rail ( 5 ) for collecting high pressure fuel discharged by the high pressure pump ( 7 ), and an ECU ( 10 ) for controlling the discharge of the high pressure pump ( 7 ) in response on the drive state of an engine and the common rail pressure (Pc). When the engine is started, the ECU ( 10 ) determines a time (Ts) that elapses before the engine speed reaches a predetermined speed (Ns) and a pressure increase characteristic (ΔP / ΔT) of the common rail pressure (Pc), and when the elapsed time (Ts) exceeds a target start time (Ta), it increases or decreases the output (D) in the next engine starting operation in response to the pressure increase characteristic (ΔP / ΔT).

Claims (12)

1. Collective fuel injector with:
a high pressure pump ( 7 ) for drawing fuel from a fuel tank ( 6 );
a common rail ( 5 ) for collecting high pressure fuel discharged by the high pressure pump;
a plurality of fuel injection valves ( 1 to 4 ), which are each attached to a respective cylinder of an internal combustion engine and inject the high-pressure fuel collected in the common rail into a combustion chamber of the cylinder;
a drive state detection unit ( 70 ) for detecting a drive state of the internal combustion engine;
a fuel pressure detection unit ( 81 ) for detecting a fuel pressure of the high pressure fuel collected in the common rail; and
an exhaust control unit ( 10 , S605, S607) for controlling an exhaust of the high pressure pump in response to the driving condition detected by the drive state detection unit and the fuel pressure detected by the fuel pressure detection unit, characterized in that when the internal combustion engine is started, the discharge control unit ( 10 , S605, S607 ) detects a time (Ts) that has elapsed before the engine speed (N) reaches a predetermined speed (Ns), and a pressure increase characteristic (ΔPc / ΔT) of the fuel pressure by the fuel pressure detection unit, and when the time detects a predetermined start time exceeds, then it increases or decreases the output at the next engine starting operation according to the pressure increase characteristic. 2. The collective fuel injection device according to claim 1, further characterized in that the high pressure pump has a quantity control valve ( 19 ) for adjusting a quantity of fuel sucked from the fuel tank, and wherein the discharge control unit changes a drive amount (D) to the quantity control valve is delivered. 3. collective fuel injection device according to claim 2, the more characterized in that the flow control valve is a linear solenoid valve. 4. collective fuel injector according to claim 2 or Claim 3, further characterized in that the drive amount delivered to the volume control valve a pulse duration control is controlled, and the Fuel emissions during the next start-up Internal combustion engine is increased when the Pressure increase characteristic is smaller than a predetermined one Value. 5. Collective fuel injection device according to one of the Claims 2 to 4, further characterized in that the pressure increase characteristic an increase in Fuel pressure per unit of time, and the Ejection control unit a predetermined upper Increase limit (UL) and a predetermined lower Boost Limit (LL) and if the Pressure increase characteristic greater than or equal to that predetermined upper increase limit, then it increases the Drive amount, and if the pressure increase characteristic less than or equal to the predetermined lower Is increase limit, then it decreases the drive amount. 6. Collective fuel injector with:
a high pressure pump ( 7 ) for drawing fuel from a fuel tank ( 6 );
a common rail ( 5 ) for collecting high pressure fuel discharged by the high pressure pump;
a plurality of fuel injection valves ( 1 to 4 ) which are attached to a respective cylinder of an internal combustion engine and inject the high-pressure fuel collected in the common rail into a combustion chamber of the cylinder;
a fuel pressure detection unit ( 81 ) for detecting a fuel pressure of the high pressure fuel collected in the common rail; and
a discharge control unit ( 10 ) for controlling discharge of the high pressure pump in response to the fuel pressure detected by the fuel pressure detection unit, further characterized by
a starting ability determination unit ( 10 , S703) that determines whether the engine speed (N1) reaches a predetermined speed (Na) when a predetermined time (T1) has passed after the engine start; and
a discharge correction unit ( 10 , S705, S706) for correcting the discharge at the next starting operation in response to an actual fuel pressure detected by the fuel pressure detection unit upon the lapse of the predetermined time and an actual engine speed, which are compared with the predetermined engine speed by the starting power determination unit becomes. 7. collective fuel injection device according to claim 6, the more characterized in that if the starting asset determination unit determines that the Engine speed does not exceed the predetermined speed reached, the output correction unit corrects the output. 8. The collective fuel injection device according to claim 6 or claim 7, further characterized in that the starting ability determination unit has a drive state detection unit ( 70 ) for detecting a drive state of the internal combustion engine and an engine start command detection unit for detecting a command to start the internal combustion engine. 9. collective fuel injection device according to one of claims 6 to 8, further characterized in that the high-pressure pump has a quantity control valve ( 19 ) for setting a quantity of fuel that is drawn in from the fuel tank, wherein the exhaust control unit changes a drive amount delivered to the quantity control valve, and the discharge correcting unit corrects the driving amount to the driving amount suitable for the high pressure pump attached to the engine using the actual fuel pressure and the actual speed of the engine with reference to data stored in advance for the correction. 10. A collective fuel injection device according to any one of claims 6 to 9, further characterized by a cylinder discrimination unit ( 10 , S801) for discriminating the cylinders and a control unit (S802) for controlling the discharge according to the cylinder discriminated by the cylinder discrimination unit. 11. Collective fuel injection device according to claim 10 of the more characterized in that if the starting asset determination unit determines that the Engine speed the predetermined speed reached, the output correction unit does not make a correction and the control unit controls the output according to the cylinder. 12. Collective fuel injection device according to claim 10 or Claim 11, wherein the predetermined speed of the Internal combustion engine is less than a lower limit speed, through which the cylinder through the discrimination unit is distinguishable.