Control device and method for controlling an injector

Abstract

The subject matter described herein specifically relates to a control device (150) and method for controlling fuel injectors (101) mounted to an internal combustion engine to allow for reduction of deviations in the amount of fuel between different injectors / different injections in ballistic operation, the control device (150) comprises a control parameter calculation unit (603), an injection pulse calculation unit (604), an injection pulse compensation unit (605) and at least one memory (607 or 608). The control parameter calculation unit (603) is configured to determine a target closing time for the fuel injector (101) based on an amount of fuel to be injected into the internal combustion engine. If the determined target closing time is greater than a maximum closing time of the fuel injector (101) in ballistic operation, the injection pulse calculation unit (604) is configured to: calculate a pulse duration of the injector (101) based on a characteristic curve of the fuel injector (101); and outputting the calculated pulse duration to a fuel injector (101) for injecting a fuel quantity into the internal combustion engine. If the determined target closing time is equal to or less than a maximum closing time in ballistic operation, the injection pulse compensation unit (605) is configured to: receive a set of parameters from the at least one memory (607 or 608); calculating a pulse duration for the fuel injector (101) based on the determined target closing time and a set of parameters; and outputting the calculated pulse duration to a fuel injector (101) for injecting a fuel quantity into the internal combustion engine.

Description

Technical Field

[0001] The subject matter relates in particular to a control device and a method for controlling a fuel injector installed in an internal combustion engine, as well as a method for adapting a pulse duration of a fuel injector and a learning unit for executing said method. Background Art

[0002] In order to comply with current stringent emission regulations, it is necessary to prevent the fuel injected into the cylinder of an internal combustion engine from reaching the cylinder wall. In order to achieve this goal, it is a promising approach to divide the amount of fuel to be injected into a number of small injections. However, in order to accurately meter small amounts of fuel, the so-called ballistic operating range of the fuel injector must be precisely controlled.

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: US2018 / 0209373 A1 Summary of the invention

[0006] Technical issues

[0007] Patent document 1 describes a control device for controlling fuel injection in an internal combustion engine, wherein a closing time of a fuel injector is determined based on a driving voltage of the fuel injector, and for each injection pulse width and each fuel injector in the internal combustion engine, a time period between a specified reference time and the closing time of the fuel injector is considered in a plurality of characteristic curves.

[0008] Solution to the problem

[0009] The subject matter described herein achieves the technical goal of improving the accuracy of small amounts of fuel to be injected into an internal combustion engine while maintaining improved accuracy during the life of the engine with reduced calibration effort. This goal can be achieved by the subject matter of the appended claims.

[0010] According to the subject matter described in the attached claims, a control device for controlling a fuel injector installed in an internal combustion engine is proposed. The control device may preferably include an engine control unit (ECU) and a drive circuit for driving the fuel injector. The control device includes a control parameter calculation unit, an injection pulse calculation unit, an injection pulse compensation unit and at least one memory. The at least one memory may be able to store data permanently and / or non-permanently. The at least one memory may also include a non-volatile memory and / or a volatile memory. The at least one memory preferably includes a read-only memory (ROM) and a random access memory (RAM).

[0011] The fuel injector may preferably be an electromagnetic injector capable of injecting fuel directly into a combustion chamber of an internal combustion engine. The fuel injector may be electrically connected to a control device, and may include a fuel supply unit disposed at an upper end of the fuel injector, a fuel injection port and a valve seat disposed at a lower end of the fuel injector, and a valve body disposed between the fuel supply unit and the valve seat.

[0012] Inside the fuel injector, a fuel channel may be provided so that fuel can flow from the fuel supply unit to the fuel injection hole. The injector coil may be arranged between the fixed iron core and the housing of the fuel injector. The fixed iron core, the injector coil and the housing may form an electromagnet.

[0013] In the valve closed state when the injector coil is not energized, the valve body can be pushed into the valve seat by the spring force of at least one spring, which can bias the valve body in the valve closing direction (towards the lower end of the fuel injector). In order to energize the injector coil, an injection pulse can be output from the control device, which can cause a drive current / drive voltage to be applied to the injection coil.

[0014] When the injection coil is energized, the valve body can be separated from the valve seat and displaced in the valve opening direction (toward the upper end of the fuel injector). Therefore, the fuel passage can be opened, and the fuel can be injected into the internal combustion engine through the fuel injection hole.

[0015] Combined with the following Figure 2 Components and functions of a fuel injector that may be controlled according to the subject matter described herein are described in detail.

[0016] A control parameter calculation unit of the control device determines a target closing time for the fuel injector based on the amount of fuel to be injected into the internal combustion engine. The term "closing time of the fuel injector" should be understood as the time period from a reference time to the time when the fuel injector is completely closed (i.e., the time when the valve body of the fuel injector is completely located on its valve seat). The reference time can be, for example, the rising edge of an injection pulse signal output by the control unit for opening the fuel injector. The time when the valve body is displaced from its valve seat can also be defined as the reference time. Any other suitable time for the opening of the fuel injector can also be selected as the reference time. It has been shown that the closing time is linearly related to the amount of fuel injected and is independent of the operating range of the fuel injector.

[0017] The amount of fuel to be injected may depend on operating conditions of the internal combustion engine, such as engine load, engine speed, air-fuel ratio, fuel pressure, etc. These operating conditions may be determined by a plurality of sensors which may be connected to the control device and which enable the control parameter calculation unit to determine the amount of fuel required for given operating conditions.

[0018] If the determined target closing time is greater than the maximum closing time of the fuel injector in ballistic operation, the injection pulse calculation unit calculates a pulse duration for the fuel injector based on a characteristic curve of the fuel injector and outputs the calculated pulse duration to the fuel injector for injecting a fuel quantity into the internal combustion engine.

[0019] "Pulse duration of a fuel injector" may be the duration / width of a control pulse (injection pulse), by which the amount of fuel to be injected may be controlled. "Ballistic operation of a fuel injector" should be understood as an operation in which the injection pulse output to the fuel injector is stopped before the valve body of the fuel injector reaches its full lift.

[0020] The maximum closing time of a fuel injector in ballistic operation may be related to a pulse duration that brings the valve body close to its full lift. This means that if the determined target closing time is greater than the maximum closing time of the fuel injector in ballistic operation, the fuel injector is operated with the full lift of the valve body. In this case, the pulse duration required to provide the amount of fuel to be injected into the internal combustion engine is determined by the injection pulse calculation unit from the characteristic curve of the fuel injector. The characteristic curve may represent the relationship between the pulse duration of the fuel injector and the associated amount of fuel delivered by the injector. The characteristic curve may be provided for a specific type of fuel injector installed in the internal combustion engine, and the characteristic curve may be permanently stored in at least one memory. However, the characteristic curve of the fuel injector only shows a defined linear relationship between the pulse duration and the amount of injected fuel when the fuel injector is operated with the full lift of the valve body.

[0021] Therefore, if the determined target closing time is equal to or less than the maximum closing time in ballistic operation, the injection pulse compensation unit receives a set of parameters from at least one memory and calculates a pulse duration for the fuel injector based on the determined target closing time and the received set of parameters.

[0022] According to a preferred example, the set of parameters may include a slope and an intercept of a first correlation between a pulse duration and a closing time of the fuel injector.The set of parameters may be stored in at least one memory.

[0023] In other words, if the fuel injector is operated in ballistic operation, a pulse duration for injecting the required fuel quantity is calculated by the injection pulse compensation unit based on the determined target closing time (which is linearly related to the fuel quantity to be injected) and the slope and intercept of the first correlation representing the relationship between the pulse duration and the closing time of the corresponding fuel injector. Subsequently, the injection pulse compensation unit outputs the calculated pulse duration to the fuel injector for injecting the fuel quantity into the internal combustion engine.

[0024] By calculating the pulse duration in the above-described manner, deviations in the injected fuel amount between different fuel injectors in ballistic operation and between different injections of a single fuel injector can be avoided without increasing the correction workload.

[0025] According to an example, the control parameter calculation unit determines a target closing time for a fuel injector based on a second correlation between the closing time of a plurality of fuel injectors and the fuel quantity. For example, the second correlation can be predetermined on a test bench for all fuel injectors installed in the internal combustion engine and can be permanently stored in at least one memory.

[0026] According to an example, the control unit may further include an injector closing time calculation unit and an injection pulse learning unit, wherein, in a learning mode of the internal combustion engine, the injection pulse learning unit may gradually increase the pulse duration of the fuel injector, and the injector closing time calculation unit may determine the closing time for each pulse duration, and may send the determined closing time back to the injection pulse learning unit. The injection pulse learning unit may then receive the closing time determined for each pulse duration from the injector closing time calculation unit, and may determine a first correlation between the pulse duration and the closing time of the fuel injector. The injector closing time calculation unit may be configured to perform mathematical operations on the drive signal (drive current, drive voltage) of the fuel injector, such as filtering the signal and deriving the signal.

[0027] According to an example, the injection pulse learning unit may calculate a slope and an intercept of a first correlation between a pulse duration and a closing time of the fuel injector for each pulse duration, and may store the calculated slope and intercept in at least one memory. Since the first correlation may not show a linear behavior, the first correlation may preferably be approximated by calculating the slope and intercept of the first correlation for subsequent pulse durations. Preferably, the slope and intercept calculated at each pulse duration may be stored non-permanently in the memory. This means that the learning process may be repeated regularly so that the first correlation is continuously adapted to the conditions of the fuel injector.

[0028] According to the example, the injection pulse learning unit can determine the closing time when the calculated slope is equal to or less than the predetermined slope value as the maximum closing time of the fuel injector in the ballistic operation, and the determined maximum closing time can be stored in at least one memory. In other words, when the closing time is determined for the pulse duration when the calculated slope a0 is equal to or less than the predetermined slope value, the closing time can be determined as the maximum closing time of the fuel injector in the ballistic operation. Since the first correlation can show a significant decrease in slope during the transition from ballistic operation to full-stroke operation, the end of the ballistic operation range can be reliably determined by setting the predetermined slope value as a threshold. This allows limiting the time required for the learning mode and the calculation workload of the control unit. For example, the predetermined slope value can be determined in advance on a test bench and can be permanently stored in at least one memory.

[0029] According to an example, the injection pulse learning unit can stop the learning mode of the internal combustion engine when determining the maximum closing time of the fuel injector in ballistic operation. In this way, only a limited number of relevant slopes and intercepts are calculated, so that the learning mode only takes a short time and does not affect driving comfort.

[0030] According to an example, the injection pulse learning unit may start the learning mode when the internal combustion engine is operating in a predetermined operation mode.

[0031] For example, the learning mode may be started after each start of the internal combustion engine, when the engine is idling. During this time, for example, the control unit may prevent the engine from being loaded until the first correlation and its slope and intercept are determined. This means that, during the operating time of the engine, the first correlation is continuously adapted, so that aging effects of the fuel injectors and environmental conditions that influence the opening / closing behavior of the fuel injectors may be taken into account over the long term.

[0032] According to an example, the injector closing time calculation unit may determine the closing time of the fuel injector based on the driving voltage curve of the fuel injector. When the injection pulse is turned off to close the fuel injector, a reverse driving voltage may be applied to the injector coil, and the current supply to the injector coil may be cut off. Due to the lack of magnetic attraction, the valve body may be pushed back to the closed position, in which position the valve body may be pushed onto the valve seat under the action of at least one spring.

[0033] At this point, the valve body hits the valve seat, and the slope of the drive voltage can change, thereby generating an inflection point. This inflection point can be used to determine when the valve is closed. For example, by forming the second-order derivative of the control voltage curve, the inflection point can be accurately determined as a maximum or minimum value.

[0034] The subject matter disclosed herein also includes an internal combustion engine comprising at least one fuel injector and the above-described control device.

[0035] Furthermore, a method for controlling a fuel injector mounted on an internal combustion engine is also claimed. Each configuration of the claimed control device should also be covered by the method, which is claimed per se and / or by means of a computer program product claim.

[0036] In addition, a method for adapting the pulse duration of a fuel injector installed in an internal combustion engine by an injection pulse learning unit in a learning mode of the internal combustion engine is also claimed. The method includes the following steps: gradually increasing the pulse duration of the fuel injector; detecting the closing time of each pulse duration; calculating the slope and intercept between the pulse duration and the closing time of the fuel injector for each pulse duration; determining the closing time at which the calculated slope is equal to or less than a predetermined slope value and / or the closing time at which the calculated slope is a negative slope value as the maximum closing time of the fuel injector in ballistic operation; after determining the maximum closing time of the fuel injector in ballistic operation, stopping the learning mode; and storing the calculated slope and intercept and the maximum closing time of the fuel injector in ballistic operation as a set of parameters in at least one memory.

[0037] The method for adapting the pulse duration of a fuel injector is intended to be carried out by a computer program product which can be stored in a memory and / or by an injection pulse learning unit for a control device.

[0038] Advantageous Effects of the Invention

[0039] In summary, the disclosed subject matter allows to significantly reduce the deviations of the fuel quantity between different fuel injectors / different injections in ballistic operation. This can be achieved by calculating the pulse duration of each fuel injector based on a generally linear relationship (second correlation) between the closing time and the injected fuel quantity Q, which linear relationship can be adapted to the individual behavior of the respective fuel injector via the first correlation between the pulse duration of each fuel injector and the closing time. The described calculation requires little correction effort and ensures that the calculated pulse duration is continuously adjusted during the operating time of the engine, so that aging effects of the fuel injectors and environmental conditions that influence the opening / closing behavior of the fuel injectors can be taken into account over the long term. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In the following, the claimed subject matter will be further explained based on at least one preferred example with reference to the accompanying drawings, in which:

[0041] Figure 1 An example of a fuel injection system for an internal combustion engine is schematically shown;

[0042] Figure 2A cross-sectional view showing an exemplary fuel injector connected to a control device including a drive circuit and an engine control unit (ECU);

[0043] Figure 3a Schematically shown for operation in the fully open state Figure 2 The injection pulse of the fuel injector depicted in;

[0044] Figure 3b schematically illustrating the associated driving voltage supplied to the fuel injector;

[0045] Figure 3c schematically illustrating the associated drive current supplied to the fuel injector;

[0046] Figure 3d The obtained valve displacement is schematically shown;

[0047] Figure 4a Schematic diagram for operation in ballistic mode Figure 2 The injection pulse of the fuel injector depicted;

[0048] Figure 4b schematically illustrating the associated driving voltage supplied to the fuel injector;

[0049] Figure 4c schematically illustrating the associated drive current supplied to the fuel injector;

[0050] Figure 4d The obtained valve displacement is schematically shown;

[0051] Figure 5 Schematically shown Figure 1 and Figure 2 Examples of hardware configurations of the depicted control devices;

[0052] Figure 6 Schematically showing a preferred example of the subject matter disclosed herein Figure 1 and Figure 2 The functional configuration of the control device depicted in;

[0053] Figure 7a Schematically illustrates the relationship between pulse duration and injection quantity for various fuel injectors not controlled according to the subject matter disclosed herein;

[0054] Figure 7b The relationship between the closing time and the injection quantity of the fuel injector is schematically shown;

[0055] Figure 8a showing a first correlation between pulse duration and closing time determined for any fuel injector;

[0056] Figure 8bThe duration of each pulse is shown in Figure 8a The slope of the exemplary first correlation depicted in ;

[0057] Figure 8c The duration of each pulse is shown in Figure 8a The intercept of the exemplary first correlation depicted in ;

[0058] Figure 9a showing an exemplary second correlation by which a target closing time for a fuel injector may be determined based on an amount of fuel to be injected into an internal combustion engine;

[0059] Figure 9b The target closing time t is shown EOI_tar and the corresponding slope a0;

[0060] Fig.9c The target closing time t is shown EOI_tar and the corresponding intercept b0;

[0061] Fig.10 shows a flow chart illustrating a preferred example of a method according to the subject matter disclosed herein;

[0062] Fig.11 shows a flow chart illustrating another preferred example of the method according to the subject matter disclosed herein;

[0063] Fig.12 The relationship between pulse duration and injected fuel quantity of a fuel injector controlled according to the disclosed subject matter is schematically illustrated. DETAILED DESCRIPTION

[0064] Figure 1 An example of a fuel injection system for an internal combustion engine is schematically shown, the system comprising a fuel pump 106, a fuel rail 105 with a pressure sensor 102, four fuel injectors 101 and a control device 150. The number of fuel injectors is not limited to four, but may be 1 to 12, for example.

[0065] In the depicted example, one fuel injector 101 is installed in each cylinder 108 of an internal combustion engine (not depicted) to inject fuel directly into a combustion chamber 107 of the cylinder 108. More than one fuel injector may also be installed in each cylinder. The fuel to be injected may be pressurized by a fuel pump 106 and delivered to the fuel injector 101 via a fuel rail 105. The fuel pressure may vary depending on the balance between the flow rate of the fuel discharged by the fuel pump 106 and the injection amount of the fuel injected into the combustion chamber 107 by the fuel injector 101. However, the discharge amount of the fuel from the fuel pump 106 may be controlled by the control device 150 based on the information of the pressure sensor 102 so that the pressure in the fuel pipe 105 becomes a predetermined pressure.

[0066] The amount of injected fuel of each fuel injector 101 can be controlled by the width (pulse duration) of the injection pulse sent from the engine control unit (ECU) 109 to the drive circuit 127. The drive circuit 127 can calculate a drive current curve based on the injection pulse received from the ECU 109. Then, the calculated drive current curve is supplied to each fuel injector 101. The drive circuit 127 can be a component of the ECU 109, or a separate device. The drive circuit 127 and the ECU 109 can be included in the control device 150.

[0067] Figure 2 Shown with Figure 1 1 is a cross-sectional view of an exemplary fuel injector connected to a control device 150 that includes a drive circuit 127 and an ECU 109.

[0068] The fuel injector 101 shown includes a fuel supply unit 212 arranged at the upper end of the fuel injector 101, a fuel injection hole 215 and a valve seat 202 arranged at the lower end of the fuel injector 101, and a valve body 201, an intermediate member 214 and a movable iron core 206 arranged between the fuel supply unit 212 and the valve seat 202.

[0069] Inside the fuel injector 101, a fuel passage is provided so that the fuel can flow from the fuel supply unit 212 to the fuel injection hole 215 along the central axis 200a of the fuel injector 101. An injector coil 208 is arranged between the fixed iron core (stator) 207 and the housing 209 of the fuel injector 101. The fixed iron core 207, the injector coil 208 and the housing 209 form an electromagnet.

[0070] In the valve closed state where the injector coil 208 is not energized, the valve body 201 is pushed into the valve seat 202 by the spring force of the first spring 210 and the second spring 216, which biases the valve body 201 in the valve closing direction (toward the lower end of the fuel injector 101). The spring force of the first spring 210 and the second spring 216 opposes the spring force of the third spring 217, which biases the movable iron core 206 in the valve opening direction (toward the upper end of the fuel injector 101) so that it abuts against the intermediate member 214. Since the spring force of the second spring 216 is greater than the spring force of the third spring 217, a gap 250 is formed between the valve body 201 and the movable iron core 206.

[0071] The drive circuit 127 and the ECU 109 are connected to the fuel injector 101. The ECU 109 can obtain information from various types of sensors (e.g., sensors installed on the fuel rail at the fuel injector 101 (see Figure 1 ) receives a plurality of sensor signals indicating the operating conditions of the internal combustion engine (not depicted), and can calculate the required fuel quantity Q according to the operating conditions of the internal combustion engine, based on which the pulse duration and injection timing of the fuel injector 101 can be calculated. The injection pulse output from the ECU 109 can be input to the drive circuit 127 through the signal line 223.

[0072] The drive circuit 127 may have a circuit that receives an injection pulse from the ECU 109 and energizes the injector coil 208 of the fuel injector 101 with a drive current / drive voltage for performing fuel injection. The ECU 109 may communicate / receive information with the drive circuit 127 via the communication line 222, and may switch the drive current generated by the drive circuit 127 according to the fuel pressure and the operating conditions of the internal combustion engine.

[0073] When the injection coil 208 is energized, a magnetic driving force may be generated by the electromagnet including the solid core 207, the coil 208, and the housing 209. Due to this magnetic driving force, a magnetic flux may circulate in a magnetic circuit passing through the coil 208, the fixed core 207, the movable core 206, the housing 209, and the movable core 206. Therefore, a magnetic attraction force acts between the movable core 206 and the fixed core 207, and the movable core 206 and the intermediate member 214 are displaced toward the fixed core 207.

[0074] The movable iron core 206 can be displaced until the transmission surface 219 of the valve body 201 abuts against the transmission surface 218 of the movable iron core 206. During this period, the valve body 201 can still be in contact with the valve seat 202. Only when the movable iron core 206 is displaced to the gap 250 generated between the valve body 201 and the movable iron core 206, so that the transmission surface 219 of the valve body 201 and the transmission surface 218 of the movable iron core 206 collide, the valve body 201 can be separated from the valve seat 202 by the kinetic energy of the movable iron core 206. Thereby, the fuel passage can be opened, and the fuel can be injected into the internal combustion engine through the fuel injection hole 215.

[0075] Once the movable iron core 206 abuts against the fixed iron core 207 during its displacement, the valve body 201 can be displaced in the valve opening direction, and the movable iron core 206 can be displaced in the valve closing direction. This means that when the fixed iron core 207 and the movable iron core 206 collide, the valve body 201 and the movable iron core 206 can be separated from each other, and the movable iron core 206 can be displaced in the valve closing direction and can be stationary at the target lift position (stable valve opening state).

[0076] Thereafter, when the power supply to the injection coil 208 is turned off and the magnetic attraction force is released, the movable iron core 206 can be pushed back to the closed position by the spring force of the first spring 210 and the force generated by the fuel pressure, in which the valve body 201 is pushed into the valve seat 202. The spring force of the first spring 210 acting on the valve body 201 can be transmitted to the movable iron core 206 via the transmission surface 219 of the valve body 201 and the transmission surface 218 of the movable iron core 206.

[0077] After the desired valve closing time, the valve body 201 may hit the valve seat 202 , and the driving surface 218 of the movable iron core 206 may separate from the driving surface 219 of the valve body 201 .

[0078] When the fuel injector 101 is closed, the third spring 217 can be turned from extension to compression, and once the valve body 201 collides with the valve seat 202, the movement direction of the movable iron core 206 can be reversed. This can change the acceleration of the movable iron core 206, thereby changing the inductance of the injector iron core 208. This effect can be used to detect the closing time of the fuel injector, as shown below in combination with Figures 3a to 3d As described.

[0079] Figures 3a to 3d Schematically shown for operation in the fully open state Figure 2 The injection pulse ti( Figure 3a ), the associated driving voltages 304, 305 supplied to the fuel injector 101 ( Figure 3b ) and associated drive currents 308, 331, 332 ( Figure 3c), and the obtained valve body 201 ( Figure 3d The dashed displacement curve 334 in FIG. 2 and the movable iron core 206 ( Figure 3d The solid line displacement curve 335) in the figure shows the displacement curve.

[0080] exist Figure 3a to Figure 3c , it can be seen that when the injection pulse ti is sent to the fuel injector 101 at time ts, the high voltage 304 is applied to the fuel injector 101, and the power supply to the injection coil 208 starts. The high voltage may be a voltage with a value of 50V or more. As a result, the movable iron core 206 is displaced in the valve opening direction (see Figure 3d The movable iron core 206 passes through the gap 250 within the delay time t0 and then abuts against the valve body 201. After that, both elements are displaced until the full lift of the valve body 201 is reached (see Figure 3d Displacement curves 334, 335).

[0081] After the current value (as indicated by the current curve 308) rises sharply due to the application of the high voltage 304 and reaches the predetermined peak current value Ip, in order to achieve the fully open state of the fuel injector 101, the application of the high voltage 304 is stopped / reduced at time t31, so that the current value is reduced to the first holding current value Ih1 according to the first current profile 331. Then, the pulse width modulated low voltage 305 is applied to the fuel injector 101 to obtain the first holding current value Ih1. The low voltage can be a battery voltage with a value in the range of 12V to 14V. In the next step, by reducing the pulse width of the low voltage 305, the current is reduced to the second holding current value Ih2 according to the second current profile 332 (see Figure 3b and 3c ). By applying holding currents Ih1 and Ih2 to the fuel injector 101, a stable valve opening state can be maintained.

[0082] Next, when the injection pulse ti is turned off at time te, the drive circuit 127 applies a reverse drive voltage to the injector coil 208 (see Figure 3b As a result, the current supply to the injector coil 208 is cut off (see Figure 3c ), the magnetic flux generated in the magnetic circuit is released, thereby releasing the magnetic attraction. Therefore, the movable iron core 206 which has lost the magnetic attraction can be pushed back to the closed position, in which the valve body 201 can hit the valve seat 202 by the load of the first spring 210 and the force caused by the fuel pressure (see Figure 3d ).

[0083] At time t EOIAt this point, the closing of valves 201 and 202 is completed, and the valve body 201 is completely located on the valve seat 202 again. When the valve body 201 hits the valve seat 202, the transmission surface 218 of the movable iron core 206 separates from the transmission surface 219 of the valve body 201 and continues to move in the valve closing direction. At this time, the slope of the driving voltage changes, thereby forming an inflection point 330 (see Figure 3b This inflection point 330 can be used to determine the time t when the valves 201 and 202 are closed. EOI .

[0084] In other words, when the fuel injector 101 is closed, the driving current flowing through the injector coil 208 is cut off, and the back electromotive force is applied to the injector coil 208. After the driving current is completely dissipated, the back electromotive force gradually decreases, and by changing the inductance when the valve body 201 collides with the valve seat 202, an inflection point 330 is generated in the driving voltage (see Figure 3b to Figure 3d ). For example, by taking a second derivative of the driving voltage curve applied to the fuel injector, the inflection point 330 may be accurately determined as a maximum value or a minimum value.

[0085] Figures 4a to 4d Schematically showing the Figure 2 The injection pulse ti ( Figure 4a ), the associated driving voltage 304 ( Figure 4b ) and associated drive current 308 ( Figure 4c ), and the obtained valve body 201 ( Figure 4d The dashed displacement curves 334a, b) and the movable iron core 206 ( Figure 4d The solid line displacement curve 335a, b) is the displacement curve.

[0086] As in Figures 3a to 3d As in FIG. 1 , an injection pulse ti is also sent to the fuel injector 101 at time ts, a high voltage 304 is applied, thereby starting the power supply to the injection coil 208, thereby causing the movable iron core 206 to be displaced in the valve opening direction (see FIG. 1 ). Figure 3d The solid displacement curve 335 in FIG. Figure 3d Similarly, the movable iron core 206 passes through the gap 250 within the delay time t0 and abuts against the valve body 201, so that both elements are displaced.

[0087] and Figures 3a to 3d The fuel injector shown operates differently, closing the injection pulse ti at time te shortly after the current curve 308 reaches the predetermined peak current value Ip, applying a reverse voltage to the fuel injector 101 (see Figure 4b and Figure 4c). As a result, the valve body 201 does not reach its full lift, but is pushed back to the closed position at about two-thirds of the lift (see Figure 4d The dashed displacement curves 334a, b in FIG.

[0088] from Figure 4d As can be clearly seen in FIG. 1 , stopping the injection pulse before the valve body reaches its full lift (ballistic operation / ballistic state of the fuel injector) may cause the core 206 (see FIG. 1 ) to Figure 4d Displacement curves 335a, b) and valve body 201 (see Figure 4d The displacement curves 335a, b) in FIG. 3 are different, which results in a different closing time t of the valves 201 and 202. EOI _a, t EOI This means that when the fuel injector is operated in ballistic operation, a stable valve opening state cannot be achieved, so that without additional measures, large deviations in the injected fuel quantity may occur.

[0089] In order to solve the above problem, the inflection points 330a, b derived from the driving voltage can be used to determine the closing time t of the valves 201, 202. EOI (See Figure 4b ). due to the closing time t EOI The defined correlation between the amount of injected fuel and the amount of injected fuel can be used to compensate for fuel deviations in ballistic operation by individually adjusting the injection pulse ti of each fuel injector 101. Figures 6 to 12 Preferred examples of implementations of such compensation according to the herein disclosed subject matter are described.

[0090] Figure 5 Schematically shown Figure 1 and Figure 2 An example of a hardware configuration of the control device 150 is depicted. In the depicted example, the hardware configuration includes a CPU 501 connected to a driver IC 502 via a communication line 222 and a signal line 223. For example, the CPU may be included in the ECU 109, and the driver IC 502 may be included in the driver circuit 127.

[0091] In addition, the depicted hardware configuration includes a boost circuit 514 for providing a high voltage VH at a high voltage source 560, and the high voltage VH is generated by boosting a battery voltage VB input to the boost circuit 514. The boost circuit 514 can be a DC / DC converter. In the depicted example, the boost circuit 514 includes a coil 530, a transistor 531, a diode 532, and a capacitor 533. The transistor 531 is connected to the CPU 501 via the driver IC 502, and the boost voltage VH output by the boost circuit 514 can be detected by the driver IC 502 or the CPU 501.

[0092] Furthermore, according to the depicted example, a switching element 505 is provided between a high voltage source 516 of the voltage boost circuit 514 and a terminal 590 on the high voltage side of the fuel injector 101. Furthermore, a switching element 507 is arranged between a low voltage source 517 and the terminal 590 on the high voltage side of the fuel injector 101, and another switching element 506 is arranged between a terminal 591 on the low voltage side of the fuel injector 101 and the ground potential 515. The switching elements 505, 506 and 507 may be transistors, preferably field effect transistors (FETs) capable of switching the fuel injector 101 on (ON) and off (OFF).

[0093] In the depicted example, a diode 535 is arranged between the terminal 590 on the high voltage side of the injector coil 208 and the switching element 505 to allow current to flow from the high voltage source 516 to the injector coil 208 and the ground potential 515. In addition, a diode 511 is provided between the terminal 590 on the high voltage side of the coil 208 and the switching element 507 to allow current to flow from the low voltage source 517 to the injector coil 208 and the ground potential 515. For example, the low voltage source 517 may be a battery supplying a voltage VB (which may be in the range of 12 to 14 V).

[0094] Furthermore, diodes 509 and 510 are provided in the depicted hardware configuration in order to apply a reverse driving voltage to the injector coil 208. Furthermore, current detection resistors 508, 512, and 513 are connected to the driver IC 502 to detect current values ​​flowing to the fuel injector 101 from the respective sources.

[0095] The CPU 501 may receive a plurality of sensor signals indicating operating conditions (not depicted) of the internal combustion engine from various types of sensors (eg, a pressure sensor 102 installed in a fuel pipe on the upstream side of the fuel injector 101) (see Figure 1 ), and the required fuel quantity Q can be calculated according to the operating conditions of the internal combustion engine, based on which the pulse duration and injection timing of the fuel injector 101 are calculated.

[0096] Afterwards, the CPU 501 may output the calculated pulse duration of the corresponding timing to the driver IC 502 of the fuel injector 101 via the signal line 223. Based on the detected current value, the driver IC 502 may switch the switch elements 505, 506, and 507 to generate the desired drive current. In other words, the switch elements 505, 506, and 507 may be switched between power on and power off by the driver IC 502 to supply the drive current to the fuel injector 101.

[0097] Figure 6 Schematically showing a preferred example of the subject matter disclosed herein Figure 1 and Figure 2 The functional configuration of the control device 150 is depicted in FIG. Figure 1 and Figure 2 As shown, the control device 150 is connected to the injector 101, and includes an ECU 109 and a drive circuit 127. According to a preferred example of the subject matter disclosed herein, the ECU 109 includes a control parameter calculation unit 603, an injection pulse calculation unit 604, an injection pulse compensation unit 605, an injection pulse learning unit, and a current distribution calculation unit 609. In addition, a read only memory (ROM) 607 and a random access memory (RAM) 608 are included in the ECU 109. The drive circuit 127 of the control device 150 includes a current distribution generation unit 601 and an injector closing time calculation unit 602.

[0098] The control parameter calculation unit 603 calculates the amount of fuel Q to be injected into the internal combustion engine (not depicted) based on the amount of fuel Q tar , determine the target closing time t for the fuel injector 101 EOI_tar Fuel quantity Q tar may depend on the operating conditions of the internal combustion engine, such as engine load, engine speed, air-fuel ratio, etc. These operating conditions may be determined by a plurality of sensors (not depicted) which may be connected to the ECU 109 and allow the latter to determine the required fuel quantity Q for given operating conditions. tar .

[0099] The control parameter calculation unit 603 may calculate the closing time t of the plurality of fuel injectors 101 based on the closing time t EOI and the fuel quantity Q, determining the fuel quantity Q to be injected tar The corresponding target closing time t EOI_tar This predetermined correlation (second correlation) may be determined in advance for all fuel injectors 101 mounted on the internal combustion engine on a test bench and stored in the ROM 607 of the ECU 109, for example.

[0100] The control parameter calculation unit 603 also determines the target closing time t EOI_tar Is it greater than the maximum closing time t of the fuel injector 101 in ballistic operation? EOI_max If this is the case, the control parameter calculation unit 603 may cause the injection pulse calculation unit 604 to calculate the pulse duration ti of the fuel injector based on the characteristic curve of the fuel injector 101 .

[0101] The characteristic curve of the fuel injector may represent the relationship between the pulse duration ti of the fuel injector 101 and the associated fuel quantity Q delivered by the fuel injector 101 (see Figure 7a). A characteristic curve may be provided for a specific type of fuel injector 101 installed in the internal combustion engine and may be stored in the ROM 607 of the ECU 109. The injection pulse calculation unit 604 may output the calculated pulse duration ti to the current distribution calculation unit 609, which may calculate the current distribution (injection start SOI, injection end EOI, peak current Ip, holding current Ih, etc.) based on the calculated pulse duration ti, and send the calculated current distribution to the current distribution generation unit 601 of the drive circuit 127 via the signal line 223. The current distribution generation unit 601 may generate the required drive current / drive voltage and supply it to the fuel injector 101 for injecting the required fuel amount Q tar Injected into an internal combustion engine.

[0102] If the control parameter calculation unit 603 determines the target closing time t EOI_tar equal to or less than the maximum closing time t of the fuel injector 101 in ballistic operation EOI_max , the injection pulse compensation unit 605 can receive the pulse duration ti and closing time t of the fuel injector 101 from the RAM 608 EOI The slope a0 and intercept b0 of the first correlation between the target closing time t EOI_tar As well as the received slope a0 and intercept b0, the pulse duration ti of the fuel injector 101 is calculated.

[0103] This means that for each fuel injector 101, the injection pulse compensation unit 605 calculates the pulse duration ti of each fuel injector 101 and the closing time t EOI The first correlation between the target closing time t EOI_tar , calculate the single pulse duration ti. For each fuel injector 101, as the fuel quantity Q to be injected tar The target closing time t is a function of EOI_tar may be the same, but the pulse duration ti and the closing time t may be determined separately for each fuel injector 101 by the injection pulse learning unit 606 EOI and stores it in RAM 608. After the injection pulse compensation unit 605 calculates the individual pulse duration ti for each fuel injector 101, it can output each pulse duration ti to the current distribution calculation unit 609, which can calculate the current distribution for each fuel injector 101 based on the calculated pulse duration ti and send it to the current distribution generation unit 601 of the drive circuit 127 via the signal line 223.

[0104] In the learning mode of the internal combustion engine, the injection pulse learning unit 605 can determine the pulse duration ti and the closing time t of the fuel injector 101. EOI During the learning mode, the injection pulse learning unit 605 can gradually increase the pulse duration ti of the fuel injector 101 of the internal combustion engine and send each pulse duration ti to the injector closing time calculation unit 602 of the driver circuit 127, and the injector closing time calculation unit 602 can determine the closing time t for each received pulse duration ti. EOI and sends it back to the injection pulse learning unit 605 via the communication line 222.

[0105] The injector closing time calculation unit 602 of the driving circuit 127 can determine the closing time t of the fuel injector based on the driving current curve of the fuel injector 101. EOI As mentioned above Figure 3b and Figure 4b As described above, when the valve body 201 strikes the valve seat 202, thereby generating an inflection point 330 of the driving voltage, the slope of the driving voltage changes (see Figure 3b and Figure 4b ). This inflection point 330, 330a, b can be used to determine the closing time t of the corresponding fuel injector 101, for example, by forming the second derivative of the control voltage curve. EOI .

[0106] Based on the closing time t received from the injector closing time calculation unit 602 EOI The injection pulse learning unit 606 can determine the pulse duration ti and closing time t of the corresponding fuel injector 101. EOI and store it in the RAM 608. In addition, the injection pulse learning unit 605 can calculate the pulse duration ti and the closing time t of the corresponding fuel injector 101 for each pulse duration ti. EOI The slope a0 and intercept b0 of the first correlation between the two are calculated, and the calculated slope a0 and intercept b0 are also stored in the RAM 608.

[0107] Calculating the slope a0 and intercept b0 of each pulse duration may mean determining the slope a0 and the corresponding intercept b0 of the closing time between two adjacent pulse durations ti. For example, the slope a0 and the intercept b0 of the first pulse duration ti1 sent to the injector closing time calculation unit 602 may be determined by, for example, using the fuel injector 101 having a value t EOI =0 is determined as the preceding pulse duration ti0 of the first pulse duration ti1.

[0108] If the injection pulse learning unit 606 gradually increases the pulse duration ti in the learning mode, the calculated slope a0 is less than the predetermined slope value a 0_thr The closing time t EOI , then it can set the closing time t EOI The maximum closing time t of the fuel injector 101 in ballistic operation is determined as EOI_max , and the determined maximum closing time t EOI_max Stored in RAM 608. This process may be repeated for all fuel injectors 101 installed in the internal combustion engine.

[0109] When the maximum closing time t of each fuel injector in ballistic operation is determined EOI_max and stored in the RAM, the injection pulse learning unit 606 may stop the learning mode of the internal combustion engine. When the internal combustion engine is operated in a predetermined operation mode, the injection pulse learning unit 606 may start the learning mode. In this case, the control parameter calculation unit 603 may cause the injection pulse learning unit 606 to gradually increase the pulse duration ti of the first fuel injector 101 for determining the closing time t of each step. EOI , and calculate the corresponding slope a0 and intercept b0 of the first correlation.

[0110] For example, the learning mode may be started after each start of the internal combustion engine at engine idling. During this time, for example, the ECU 109 may prevent the engine from being loaded until the first correlation and its slope a0 and intercept b0 have been determined for all fuel injectors 101. This means that, during the operating time of the engine, the first correlation is constantly adjusted, so that aging effects of the fuel injectors 101 and environmental conditions that influence the opening / closing behavior of the fuel injectors 101 can be taken into account over the long term. Since the maximum closing time t of each fuel injector 101 in ballistic operation is reached, the first correlation is adjusted to the maximum closing time t of each fuel injector 101 in ballistic operation. EOI_max The learning mode is terminated when the vehicle is in the learning state, so the learning mode can last only for a short time without affecting driving comfort.

[0111] Figure 7a The relationship between the pulse duration ti and the injection quantity Q of different fuel injectors 101 that are not controlled according to the disclosed subject matter is schematically shown. The relationship shown as a dashed line may be a typical curve for the type of fuel injector and may be stored as a characteristic curve in the ECU 109. Figure 7aIt can be clearly seen in Figure 1 that when the fuel injector 101 is operated in the ballistic regime (i.e., the injection pulse ti terminates before the valve body 201 reaches its full lift), the same pulse duration ti can result in different fuel quantities Q for different fuel injectors 101. In other words, if the characteristic curve of the fuel injector 101 is used to meter the fuel quantity Q in ballistic operation, large deviations in the injected fuel quantity Q will be expected. Even for a single injector 101 operating in ballistic operation, large deviations in the injected fuel quantity Q will occur between different injections at the same pulse duration ti.

[0112] Therefore, according to the subject matter disclosed herein, only when the closing time t EOI is greater than the maximum closing time t of the fuel injector 101 in ballistic operation EOI_max The characteristic curve of the fuel injector 101 is used to meter the fuel quantity Q to be injected. In other words, the characteristic curve of the fuel injector 101 is used only when the fuel injector 101 is operated in a stable valve opening state / fully open state in which the valve body 201 reaches its full lift. Figure 7a It is shown that in this case the characteristic curve has a linear behavior over the pulse duration ti with a slope a full , the intercept is b full , and only small deviations in the injected fuel quantity Q between different fuel injectors / different injections are expected.

[0113] Figure 7b Schematically shown as Figure 7a The closing time t of the same fuel injector 101 shown in FIG. EOI The relationship between the injection quantity Q. Figure 7b The closing time t of the fuel injector 101 is shown. EOI There is a linear relationship between t and the fuel quantity Q. This relationship is valid over the entire operating range of the fuel injector 101 (i.e., for ballistic operation and operation at the full lift of the valve body 201). Therefore, the target closing time t can be determined using the slope a1 and intercept b1 of a single correlation (second correlation) that is valid for all fuel injectors 101 installed in the internal combustion engine. EOI_tar , the slope and intercept may be determined once and stored in the ROM 607 of the ECU 109 .

[0114] Figure 8a-8c Schematically illustrates a preferred example of calculating the slope and intercept of the first correlation for each pulse duration according to the subject matter disclosed herein. Specifically, Figure 8a The pulse duration ti and closing time t determined for any fuel injector 101 are shown. EOI Example of a first correlation between t EOIand the fuel quantity Q depend linearly on each other (see Figure 7b ), so the first correlation proceeds in the same way as in Figure 7a As described above, during the learning mode of the internal combustion engine, by gradually increasing the pulse duration ti applied to the fuel injector 101 and determining the closing time t for each pulse duration ti EOI , to determine the first correlation. The change of the pulse duration may start at the delay time t0 of the corresponding fuel injector 101, and the preliminary maximum pulse duration t i_max Set in advance to determine the closing time t EOI The final pulse duration.

[0115] Figure 8b and 8c The values ​​determined for each pulse duration ti are shown in Figure 8a The slope a0 and intercept b0 of the exemplary first correlation depicted in . This means that Figure 8b The slope a0 and Figure 8c The corresponding intercept b0 depicted in Figure 8a The exemplary first correlation depicted in FIG. 1 is determined between two adjacent pulse durations ti.

[0116] If the calculated slope a0 is equal to or less than the predetermined slope value a0_ thr The pulse duration t i_e Determine the closing time t EOI , the closing time t EOI The maximum closing time t of the fuel injector 101 in ballistic operation is determined as EOI_max Since the first correlation shows a significant drop in slope during the transition from ballistic operation to full stroke operation (see Figure 8a ), so the predetermined slope value a0_ thr Set as the threshold to reliably determine the end of the ballistic operating range t i_e This allows limiting the time required for the learning mode and the computational workload of the control unit 150. For example, the predetermined slope value a0_ can be determined in advance on a test bench for all fuel injectors 101 installed in an internal combustion engine. thr , and store it in the ROM 607 of the ECU 109. i_e The slope a0 and intercept b0 determined by the pulse duration are stored in RAM 608.

[0117] Figures 9a to 9c Schematically illustrating a method for switching on a target closing time t according to the subject matter disclosed herein. EOI_tarThe corresponding slope a0 and intercept b0 determine the pulse duration of a single fuel injector. Specifically, Figure 9a An exemplary second correlation is shown, by which the fuel quantity Q to be injected into the internal combustion engine can be used to determine the fuel quantity Q to be injected into the internal combustion engine. tar Determine the target closing time t of the fuel injector 101 EOI_tar After determining the target closing time t EOI_tar Thereafter, the associated slope a0 and intercept b0 determined in the learning mode for each fuel injector 101 may be read from RAM 608 (see Figure 9b and 9c ). The required pulse duration t for a single fuel injector 101 in ballistic operation can then be calculated using the following formula i_bal :

[0118]

[0119] Among them, according to Figure 9a , apply the following:

[0120]

[0121] This means that the closing time t EOI The generally linear relationship (second correlation) between the injected fuel quantity Q and the pulse duration t of the individual fuel injector 101 is determined. i_bal , which can be seen via the pulse duration ti and closing time t of each fuel injector 101 EOI The first correlation between φ and φ is adapted to the individual behavior of the respective fuel injector 101 . Figures 8a to 8c and Figures 9a to 9c The steps of the process described in Fig.10 and Fig.11 The flowchart described in is used to explain.

[0122] Fig.10 A flow chart is shown which illustrates a preferred example of a method according to the subject matter disclosed herein. Specifically, Fig.10 An example is shown of how to calculate the required fuel quantity Q tar Determine the required pulse duration t for a single fuel injector 101 i_bal or i_full In the first step S1001 after starting the method, the amount of fuel to be injected Q can be determined according to the operating conditions of the internal combustion engine. tar In the next step S1002, the target closing time t can be determined according to the above formula (2) through the second correlation stored in the ROM 607 of the ECU 109. EOI_tar (See also Figure 9a ).

[0123] If the target closing time t is determined EOI_tar Less than the maximum closing time t in ballistic operation EOI_max , the method can proceed to step S1004: read out from RAM 608 the target closing time t EOI_tar The slope a0 and intercept b0 of the associated fuel injector are determined based on the target closing time t EOI_tar As well as the slope a0 and intercept a0 read out from RAM 608, the required pulse duration t of the corresponding fuel injector 101 can be calculated in step S1005 according to equation (1): i_bal The obtained injection pulse may be output to the fuel injector 101 (S1006). After the injection pulse is output in step S1006, the method may be terminated.

[0124] If the target closing time t is determined EOI_tar Greater than the maximum closing time t in ballistic operation EOI_max , the method can proceed to step S1003 and the pulse duration t can be determined according to the characteristic curve of the fuel injector 101 i_full (See Figure 7a ). The resulting injection pulse may then be output to the fuel injector 101 (S1006), after which the method may terminate.

[0125] Fig.11 A flow chart is shown which illustrates another preferred example of the method according to the subject matter disclosed herein. Specifically, Fig.11 The first correlation and its slope a0 and intercept b0 are shown by way of example how they can be determined for an individual fuel injector 101 during the learning mode. After starting the method, an initial pulse duration ti1 can be set in step S1101 and an injection pulse resulting from the initial pulse duration ti1 can be output to the fuel injector 101 in step S1102. Thereafter, in step S1103, a closing time t corresponding to the initial pulse duration ti1 can be detected. EOI1 and use the closing time as t EOI =0 is used as the starting point to calculate the slope a of the initial pulse duration. 01 and intercept b 01 (S1104). In the next step S1105, the determined closing time t EOI1 and the slope a of the calculated initial pulse duration ti1 01 and intercept b 01Stored in the RAM 608 of the ECU 109. Then, in step S1106, the initial pulse duration ti1 may be increased by a time period Δt to reach a second pulse duration ti2. The time period Δt ranges from 0.001 ms to 0.4 ms.

[0126] If the second pulse duration ti2 or any subsequent pulse duration ti is greater than the preliminary maximum pulse duration t i_max , the method terminates. When the second pulse duration ti2 is greater than the preliminary maximum pulse duration t i_max In the case of 01 and intercept b 01 To calculate the required pulse duration t of the fuel injector 101 in ballistic operation i_bal However, if the second pulse duration ti2 or any subsequent pulse duration ti is less than the preliminary maximum pulse duration t i_max , the method may proceed to step S1107, and the injection pulse obtained from the pulse duration ti2 (or the subsequent pulse duration ti) may be output to the fuel injector 101. Thereafter, in step S1108, the closing time t corresponding to the corresponding pulse duration ti may be detected. EOIi , and calculate the slope a of the pulse duration 0i and intercept b 0i (S1109).

[0127] In other words, the off time t between two subsequent pulse durations ti can be determined in step S1109. EOI The slope a 0i and the corresponding intercept b 0i As long as the calculated slope a 0i Greater than the predetermined slope value a 0_thr , the determined closing time t for each pulse duration ti can be converted into EOIi And the calculated slope a 0i and intercept b 0i is stored in the RAM 608 of the ECU 109. Afterwards, in step S1114, the pulse duration ti may be increased again by a period of time Δt. 0i Equal to or less than a predetermined slope value a0_ thr , the determined closing time t EOIi Set to the maximum closing time t EOI_max , and stored in RAM 608 (steps S1110 and S1111). i_balAll relevant parameters necessary are now available in the RAM 608 , so the method can be terminated for the respective fuel injector 101 .

[0128] Fig.12 The relationship between the pulse duration ti and the injection quantity Q of different fuel injectors 101 controlled according to the subject matter disclosed herein is schematically shown. Fig.12 The characteristic curves of the different fuel injectors 101 depicted in FIG. Figure 7a When comparing the characteristic curves depicted in FIG. 1 , it is apparent that by calculating the required pulse duration t in ballistic operation as described above i_bal , the deviation of the fuel amount can be greatly reduced. Specifically, the subject matter disclosed herein is able to reduce the deviation of the fuel amount between different fuel injectors / different injections in ballistic operation to the level of full lift operation. This can be achieved by EOI The pulse duration t of the individual fuel injector 101 is calculated from the generally linear relationship (second correlation) between the injected fuel quantity Q and i_bal This generally linear relationship can be achieved by the pulse duration ti of each fuel injector 101 and the closing time t EOI The first correlation between is adapted to the individual behavior of the respective fuel injector 101. The calculation requires little correction effort and ensures a continuous adjustment of the calculated pulse duration during operation of the engine, so that aging effects of the fuel injector 101 and ambient conditions that influence the opening / closing behavior of the fuel injector 101 can be taken into account over the long term.

[0129] Reference numerals list

[0130] 101 Fuel Injector

[0131] 150 Control Device

[0132] 602 Injector closing time calculation unit

[0133] 603 Control parameter calculation unit

[0134] 604 Ejection Pulse Calculation Unit

[0135] 605 Jet Pulse Compensation Unit

[0136] 606 Jet Pulse Learning Unit

[0137] 607 Read-Only Memory (ROM)

[0138] 608 Random Access Memory (RAM)

Claims

1. A control device for controlling a fuel injector installed in an internal combustion engine, the control device comprising a control parameter calculation unit, an injection pulse calculation unit, an injection pulse compensation unit and at least one memory, wherein: The control parameter calculation unit is configured to determine a target closing time of the fuel injector based on an amount of fuel to be injected into the internal combustion engine, If the determined target closing time is greater than a maximum closing time of the fuel injector in ballistic operation, the injection pulse calculation unit is configured to: calculate a pulse duration for the injector based on a characteristic curve of the fuel injector; and outputting the calculated pulse duration to the fuel injector for injecting the fuel quantity into the internal combustion engine, and If the determined target closing time is equal to or less than the maximum closing time during the ballistic operation, the injection pulse compensation unit is configured to: receive a set of parameters related to the determined target closing time from the at least one memory; calculate a pulse duration for the fuel injector based on the received set of parameters; And outputting the calculated pulse duration to the fuel injector for injecting the fuel quantity into the internal combustion engine.

2. The control device according to claim 1, wherein: The set of parameters includes a slope and an intercept of a first correlation between a pulse duration and a closing time of the fuel injector, the set of parameters being stored in the at least one memory.

3. The control device according to claim 1, wherein: The control parameter calculation unit is configured as follows: Based on a second correlation between closing times and fuel amounts of a plurality of fuel injectors, target closing times for the fuel injectors are determined.

4. The control device according to claim 1, further comprising an injector closing time calculation unit and an injection pulse learning unit, in, In the learning mode of the internal combustion engine, The injection pulse learning unit is configured to gradually increase the pulse duration of the fuel injector, The injector closing time calculation unit is configured to: determine a closing time for each pulse duration; and send the determined closing time to the injection pulse learning unit, and The injection pulse learning unit is configured to: receive the determined closing time of each pulse duration from the injector closing time calculation unit; and determine a first correlation between the pulse duration and the closing time of the fuel injector.

5. The control device according to claim 4, wherein: The ejection pulse learning unit is configured as follows: calculating, for each pulse duration, a slope and an intercept of a first correlation between a pulse duration and a closing time of the fuel injector; as well as The calculated slope and intercept are stored in the at least one memory.

6. The control device according to claim 5, wherein: The ejection pulse learning unit is configured as follows: determining a closing time at which the calculated slope is equal to or less than a predetermined slope value as a maximum closing time of the fuel injector in ballistic operation; as well as The determined maximum closing time is stored in the at least one memory.

7. The control device according to claim 6, wherein: The ejection pulse learning unit is configured as follows: When a maximum closing time of the fuel injector in ballistic operation is determined, a learning mode of the internal combustion engine is stopped.

8. The control device according to claim 4, wherein: The ejection pulse learning unit is configured as follows: The learning mode is started when the internal combustion engine is operating in a predetermined operation mode.

9. The control device according to claim 1, wherein: The injector closing time calculation unit is configured as follows: Based on a driving current curve of the fuel injector, a closing time of the fuel injector is determined.

10. An internal combustion engine comprising at least one fuel injector and a control device according to claim 1.

11. A method for a control device to control a fuel injector installed in an internal combustion engine, the control device comprising a control parameter calculation unit, an injection pulse calculation unit, an injection pulse compensation unit and at least one memory, the method comprising the following steps: determining, by the control parameter calculation unit, a target closing time for the fuel injector based on an amount of fuel to be injected into the internal combustion engine; If the determined target closing time is greater than the maximum closing time of the fuel injector in ballistic operation, then: calculating, by the injection pulse calculation unit, a pulse duration of the fuel injector based on a characteristic curve of the fuel injector; outputting the calculated pulse duration by the injection pulse calculation unit to the fuel injector for injecting the fuel quantity into the internal combustion engine; If the determined target closing time is equal to or less than the maximum closing time in ballistic operation, then: receiving, by the injection pulse compensation unit, from the at least one memory, a set of parameters associated with the determined target closing time; calculating, by the injection pulse compensation unit, a pulse duration for the fuel injector based on the received set of parameters; The calculated pulse duration is output by the injection pulse compensation unit to the fuel injector for injecting the fuel quantity into the internal combustion engine.

12. The method according to claim 11, wherein: The set of parameters includes a slope and an intercept of a first correlation between a pulse duration and a closing time of the fuel injector from the at least one memory, the set of parameters being stored in the at least one memory.

13. The method according to claim 11, wherein: The target closing time for the fuel injector is determined by the control parameter calculation unit based on a second correlation between the closing time and the fuel amount of the plurality of fuel injectors.

14. The method according to claim 11, wherein: The control unit further includes an injector closing time calculation unit and an injection pulse learning unit, and In a learning mode of the internal combustion engine: increasing the pulse duration of the fuel injector step by step by the injection pulse learning unit, The closing time of each pulse duration is determined by the injector closing time calculation unit and sent to the injection pulse learning unit, and The determined closing time for each pulse duration is received by the injection pulse learning unit, and a first correlation between the pulse duration and the closing time of the fuel injector is determined.

15. The method according to claim 14, wherein: A slope and an intercept of the determined first correlation between the pulse duration and the closing time of the fuel injector are calculated by the injection pulse learning unit for each pulse duration and stored in the at least one memory.

16. The method according to claim 15, wherein: The closing time at which the calculated slope is equal to or less than a predetermined slope value is determined by the injection pulse learning unit as a maximum closing time of the fuel injector in ballistic operation and stored in the at least one memory.

17. The method according to claim 16, wherein: When the maximum closing time of the fuel injector in the ballistic operation is determined, the learning mode of the internal combustion engine is stopped by the injection pulse learning unit.

18. The method according to claim 14, wherein: The learning mode is started by the injection pulse learning unit when the internal combustion engine is operating in a predetermined operation mode.

19. The method according to claim 11, wherein: Based on a driving current curve of the fuel injector, a closing time of the fuel injector is determined.

20. A computer program product storable in a memory comprising instructions which, when executed by a computer, cause the computer to perform the method according to claim 11.

21. A method for adapting a pulse duration of a fuel injector installed in an internal combustion engine by an injection pulse learning unit in a learning mode of the internal combustion engine, the method comprising the following steps: gradually increasing a pulse duration of the fuel injector; Detect the off time of each pulse duration; for each pulse duration, calculating a slope and an intercept between the pulse duration and the closing time of the fuel injector; determining a closing time at which the calculated slope is equal to or less than a predetermined slope value and / or a closing time at which the calculated slope has a negative slope value as a maximum closing time of the fuel injector in ballistic operation; after determining a maximum closing time of the fuel injector in ballistic operation, terminating the learning mode; as well as The calculated slope and intercept and the maximum closing time of the fuel injector in ballistic operation are stored as a set of parameters in at least one memory.

22. The method according to claim 21, wherein: The learning mode is started by the injection pulse learning unit when the internal combustion engine is operating in a predetermined operation mode.

23. The method according to claim 21, wherein: Based on a driving current curve of the fuel injector, a closing time of the fuel injector is determined.

24. A computer program product capable of being stored in a memory comprising instructions which, when executed by a computer, cause the computer to perform the method according to claim 21.

25. An injection pulse learning unit for a control device, the control device being configured to execute the method according to claim 21.

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