FUEL INJECTION FAILURE COMPENSATION

Abstract

A method (100) for adjusting the timing of fuel injection into a combustion chamber (24) of a compression ignition engine (12), the method (100) comprising: Detect (102), via an electronic control (60), a request to generate zero torque by the motor; Switching off (104), via the electronic control (60), of the fuel supply to the combustion chamber (24) during the detected requirement to generate a torque of zero; Issue (106), via the electronic control (60), a command to inject a test quantity of fuel into the combustion chamber (24) while the detected requirement to generate zero torque exists; Assess (108), via the electronic control (60), a time delay (74) between the command given to inject the test fuel quantity and the start of the injection of the test fuel quantity; Determine (110), via the electronic control (60), a compensation for the assessed time delay (74); Detect (116), via the electronic control (60), a request to generate a positive torque by the motor and commands (118), via the electronic control (60), a shift in the timing of fuel injection into the combustion chamber (24) by the determined compensation during positive torque generation by the engine.

Description

[0001] The present disclosure relates to a system and a method for measuring and compensating for errors in fuel injection in a compression-ignition engine.

[0002] Modern internal combustion engines typically use electronic fuel control to regulate engine output torque. In a gasoline engine (or spark-ignition engine), the amount of air supplied to the engine is controlled by an electronic throttle control (ETC) to determine the amount of injected fuel and thus regulate the engine's output torque. In contrast, in compression-ignition (C-Ignition) or diesel engines, the engine's output torque is usually controlled directly by the amount of injected fuel. Additionally, a specific amount of injected fuel must be precisely timed to appropriately regulate the engine's output torque, efficiency, and exhaust emissions.

[0003] DE 698 29 142 T2 discloses a fuel injection method and a corresponding device for internal combustion engines in which fuel is taken from a common high-pressure storage tank and injected into combustion chambers via injectors.

[0004] DE 10 2013 211 728 A1 discloses a method for correcting the injection start of injectors of an internal combustion engine, in which a target start of the current supply is determined as a function of at least one engine parameter, a pressure in an individual storage device of the injector is recorded and a measured injection start is derived from it, a target injection delay is determined, an actual injection delay is calculated from the target start of the current supply and the measured injection start, the target and actual injection delay are compared with each other and on the basis of this comparison a correction value for the start of the current supply is determined and used to adjust the start of the current supply.

[0005] DE 10 2012 100 938 B4 discloses an arrangement in which injection rate parameters are calculated from a fuel pressure profile, these are stored together with a fuel injection quantity as learning values, a learning pulsation waveform is estimated from the periodic variation of the learning values, and injection rate parameters for a required fuel injection quantity are determined by interpolation of this waveform.

[0006] DE 10 2006 023 468 B3 discloses a method for reducing quantity deviations in the fuel injection of an internal combustion engine, in which a test injection is carried out for at least one individual injector during a deceleration phase, wherein the fuel supply to the rail is shut off and the injector is controlled for a defined time with a target value for the amount of fuel to be injected, a deviation between the target and actual quantity is determined from a pressure difference in the fuel rail measured before and after the test injection and a correction factor for adjusting the control of the injector for subsequent injections is derived from this.

[0007] DE 10 2005 018 576 B4 discloses a common-rail fuel injection system in which a high-pressure accumulator provides fuel, an injector injects the fuel, and a control unit regulates the injection quantity depending on the operating state via an electrically actuated valve, wherein a rail pressure sensor detects the pressure in the high-pressure accumulator and, after fulfillment of a learning condition, the control unit determines a deviation in the discharge quantity from a pressure drop over time and uses this to individually correct the injection quantity of each individual injector, wherein the injector has a control chamber with inlet and outlet of the high-pressure fuel and a nozzle which injects fuel when an opening pressure is undershot and thereby releases a defined discharge quantity to the low-pressure side. DESCRIPTION

[0008] The object of the invention is to improve fuel injection. This object is achieved by the subject matter according to claim 1. Further developments are described in the dependent claims.

[0009] A method for adjusting the timing of fuel injection into the combustion chamber of a compression-ignition engine is provided. The method includes the detection of a request to generate zero torque by the engine via an electronic control system.

[0010] The method also includes shutting off the fuel supply to the combustion chamber via the electronic control unit during the detected request to generate zero torque. The method further includes issuing a command via the electronic control unit to inject a test fuel quantity into the combustion chamber during the detected request to generate zero torque. The method also includes evaluating any timing error or delay between the command to inject the test fuel quantity and the commencement of the injection of the test fuel quantity via the electronic control unit. The method further includes compensating for the evaluated timing delay via the electronic control unit by shifting the timing of the command to inject the test fuel quantity when a non-zero torque generation request is detected by the engine.

[0011] The compression-ignition engine can include a crankshaft configured to move a piston back and forth within a cylinder, thereby defining the combustion chamber, and a crankshaft position sensor connected to the electronic control unit and configured to detect the angular position of the crankshaft. The engine can further include a high-pressure fuel rail configured to supply fuel to the fuel injector, and a fuel pressure sensor connected to the electronic control unit and configured to detect the fuel pressure in the fuel rail.

[0012] The method can further include determining the fuel pressure in the fuel line while the test fuel quantity is being supplied to the fuel injector. Additionally, the method can include correlating the determined fuel pressure with the crankshaft angle to determine the timing of the command to inject the test fuel quantity relative to the crankshaft angle.

[0013] The method can further include sampling the fuel pressure signals at a frequency greater than or equal to 100 times per stroke of the compression-ignition engine.

[0014] The evaluation of the time delay can include determining the timing of the command to inject the test fuel quantity in relation to a drop in the detected fuel pressure, i.e., the actual start of injection into the combustion chamber.

[0015] The evaluation of the time delay may further include the identification of two successive sampled fuel pressure signals from a fuel pressure sensor via the drop in the detected fuel pressure within a sampling window of the crankshaft angular position and the determination of a distance between the two successive sampled signals with respect to the crankshaft angular position and a midpoint of the distance between the two successive sampled signals via the electronic control.

[0016] The compensation for the assessed time delay may involve shifting the timing of the command to inject the test fuel quantity before the determined midpoint.

[0017] The procedure may additionally include checking, after determining the compensation for the assessed time delay, whether the drop in the detected fuel pressure persists between the two successive fuel pressure signals.

[0018] If the drop in the detected fuel pressure does not remain between the two successive fuel pressure signals, the procedure may additionally include adjusting the time offset of the command to forward-inject the test fuel quantity by one quarter of the determined interval between the two successive sampled fuel pressure signals.

[0019] If the drop in the detected fuel pressure between the two successive fuel pressure signals persists, the procedure may additionally include adjusting the time offset of the command to reinject the test fuel quantity by one quarter of the determined interval between the two successive sampled fuel pressure signals.

[0020] The procedure may additionally include comparing the determined compensation for the assessed time delay via the electronic control with a target threshold time delay and setting a diagnostic fault code in the motor vehicle if the determined compensation is greater than the target threshold time delay.

[0021] The procedure can also include storing the shifted timing of the command to inject the test fuel quantity in a memory of the electronic control unit and adjusting the timing of the fuel supply to the combustion chamber when a requirement to generate non-zero torque is detected.

[0022] An engine system for a motor vehicle, which uses an electronic control system programmed with an algorithm and can be operated to carry out the above procedure, is also disclosed.

[0023] The above-mentioned features and advantages, as well as other features and advantages of the present disclosure, are readily apparent from the following detailed description of the preferred embodiments and modalities for carrying out the disclosure in conjunction with the accompanying figures. FIGURE DESCRIPTION Fig. Figure 1 is a schematic representation of a vehicle with a self-igniting internal combustion engine operated by an electronic control system. Fig. 2 is a schematic perspective close-up of the in Fig. 1. Partial view of the engine shown. Fig. Figure 3 is a diagram that provides an exemplary representation of a fuel injection pulse transmitted via the in Fig. 1-2 shows the electronic control unit being commanded, in comparison to the fuel injection rail pressure; in particular, a time error between the given injection command and the start of the injection is shown. Fig. Figure 4 is a diagram showing an exemplary representation of the fuel injection pulse ordered via the electronic control in comparison to the fuel injection pressure in the injection line; in particular, an intermediate shift of the injection timing is shown, which compensates for the timing error, according to the present disclosure. Fig. Figure 5 is a diagram showing an exemplary representation of the fuel injection pulse ordered via the electronic control in comparison to the fuel injection rail pressure; in particular, the start of injection after a final shift of the injection timing, which compensates for the timing error, is shown in accordance with the present disclosure. Fig. Figure 6 is a flowchart of a procedure for operating the compression-ignition engine via the in Fig. 1-5 shown electronic control. DETAILED DESCRIPTION

[0024] Referring to the figures, where identical reference numbers refer to identical components, shows Fig. Figure 1 shows a schematic representation of a motor vehicle 10. The motor vehicle 10 has a drivetrain that includes an internal combustion engine 12. The engine 12 is configured as a compression-ignition or diesel engine to generate engine torque. The engine 12 typically transmits its torque to the drive wheels 14 and 16, respectively, via a multi-stage transmission 18 and a drive shaft or cardan shaft 20, as illustrated in an exemplary embodiment in Fig. 1 shows.

[0025] As in Fig. As shown in Figure 2, the engine 12 comprises a crankshaft 22 and one or more cylinders, each defining a combustion chamber 24 configured to burn a mixture of fuel and air. Although a single combustion chamber 24 is shown, the engine 12 can contain as many such combustion chambers as the specific design of the engine requires. The engine 12 also includes an intake port 26, which is in fluid communication with the combustion chambers 24.

[0026] The intake duct 26 is designed such that an intake air flow 28 from the atmosphere or the environment is directed to the combustion chambers 24. As shown in Fig. As shown in Figure 1, a throttle 30, e.g. with a movable throttle valve 30A (in Fig. 2 shown), positioned at the inlet channel 26 and set up to control the supply of the inlet airflow 28 supplied to the combustion chambers 24 through the inlet channel 26.

[0027] As additionally in Fig. As shown in Figure 2, each combustion chamber 24 also contains a piston 32 and a connecting rod 33. Each piston 32 is arranged so that it moves back and forth within its respective combustion chamber 24 under the combustion force, thereby rotating the crankshaft 22 via the connecting rod 33 and regulating the volume of the combustion chamber. As further shown in Figure 2, each combustion chamber 24 also contains a piston 32 and a connecting rod 33. Fig. As shown in Figure 2, each combustion chamber 24 can be equipped with a first inlet valve 34, a second inlet valve 36, a first exhaust valve 38, and a second exhaust valve 40. Each inlet valve 34, 36 is configured to control the supply of air, or of air and fuel, to the respective combustion chamber 24 when the engine 12 generates torque and drives the vehicle 10. Each exhaust valve 38, 40 is configured to control the removal of afterburn exhaust gas 42 from the respective combustion chamber 24 via an exhaust port 44. Although two inlet valves 34, 36 and two exhaust valves 38, 40 are described here and shown in the figures, this does not preclude the engine 12 from being equipped with fewer or more inlet and exhaust valves.

[0028] The engine 12 additionally includes fuel injectors 46. At least one fuel injector 46 is provided for each combustion chamber 24, configured to supply a metered quantity of fuel 48 for mixing with the intake air stream 28 and for combustion within the respective combustion chamber 24. The engine 12 also includes a high-pressure fuel rail 50, configured to supply fuel 48 to each fuel injector 46. The fuel injector 46 is typically operated by a fuel injector driver 51 in response to a signal received from an electronic control unit, which is described in more detail below. The fuel rail is supplied with fuel via a fuel pump 52, which is connected to a fuel reservoir or tank 54.Although the diesel engine 12 is shown with the previously discussed throttle valve 30A, the engine can be configured to operate without such a throttle valve. In such a configuration of the diesel engine, combustion in the combustion chambers 24 is controlled by the amount of fuel introduced into the respective combustion chambers by the respective fuel injectors 46, the injected fuel combining with the air drawn into the respective combustion chambers by the respective pistons 31.

[0029] As in Fig. 1 and Fig. As shown in Figure 2, the engine 12 can additionally include a turbocharger 56, which is arranged at the intake port 26 and configured to pressurize the intake airflow 28 before it is directed into the combustion chambers 24. Although the turbocharger 56 is shown, this does not preclude the engine 12 from being configured and operated without such a performance-enhancing device. The exhaust port 44 is configured to direct the exhaust gas 42 from the combustion chambers 24 to the turbocharger 56 to pressurize the intake airflow 28 and then direct the exhaust gas to an exhaust system 58. The injection of the fuel 48 via the injectors 46 is synchronized with the operation of the turbocharger 56.As shown, the exhaust system 58 typically includes aftertreatment devices or catalysts, generally indicated by the numbers 58A and 58B, and designed to methodically remove largely carbon-containing particulate by-products of engine combustion from the exhaust gas 42 and reduce the emissions of such particles into the atmosphere.

[0030] With further reference to the Fig. 1 and Fig. 2. The vehicle 10 also contains an electronic control unit 60, such as an engine control unit (ECU) or an electronic control module (ECM), which is configured, i.e., structured and programmed, to control the operation of the engine 12 together with the operation of the turbocharger 56. The control unit 60 is part of a vehicle engine system and contains a memory that is tangible and non-temporary. The memory can be a writable medium involved in providing computer-readable data or process instructions. Such a medium can take many forms, including, but not limited to, non-volatile and volatile media. Non-volatile media can be, for example, optical or magnetic disks and other persistent storage devices. Volatile storage devices can include, for example, dynamic random access memory (DRAM), which can represent main memory.Such commands can be transmitted through one or more transmission media, including coaxial cable, copper wire, and fiber optics, including the wires comprising a system bus coupled to a computer processor. The memory of the controller 60 can also include a flexible disk, a hard disk, magnetic tape, another magnetic medium, a CD-ROM, a DVD, another optical medium, etc. The controller 60 is equipped with an internal clock 62, the necessary analog-to-digital (A / D) and / or digital-to-analog (D / A) circuitry, input / output (I / O) circuitry and devices, and suitable signal conditioning and / or buffering circuitry. Algorithms required by or accessible to the controller 60 can be stored in memory and executed automatically to provide the required functionality.

[0031] The control unit 60 communicates electronically with the fuel injectors 46 and is configured to control the supply of fuel 48 to the combustion chambers 24 at specific time intervals to support the desired operation of the engine 12 while the vehicle 10 is being driven. The engine 12 also includes a fuel pressure sensor 64, which is operationally connected to the fuel rail 50 and communicates electronically with the control unit 60. The vehicle 10 includes a throttle position switch 66, such as an accelerator pedal, equipped with a throttle position sensor configured to request torque generation from the engine 12. The throttle position switch 66 communicates electronically with the control unit 60. The control unit 60 is configured to detect a request for zero torque generation from the engine 12 via the throttle position switch 66.The request for zero-torque generation by the engine 12, e.g., the detection that the driver has completely released the accelerator pedal, is specifically recognized when the engine speed is above the idle speed, which can be detected by an engine speed sensor (not shown), causing the vehicle 10 to enter a coasting mode. The control unit 60 is also configured to interrupt or shut off the supply of fuel 48 to the combustion chambers 24 by closing the injectors 46 during the detected request for zero-torque generation by the engine 12.

[0032] As in Fig. As shown in Figure 2, the engine 12 can include a crankshaft position sensor 68 configured to detect the instantaneous angular position θ of the crankshaft 22 and transmit high-frequency pressure signals indicating this to the controller 60. After the fuel cut-off has been implemented during the detected request for zero-torque generation by the engine 12, and using the signals from the crankshaft position sensor 68, the controller 60 is configured to issue a command 70 to inject a test quantity 72 of fuel 48 at a specific time 73 (shown in Figure 2). Fig. 1-3) relative to the angular position θ of the crankshaft 22, inject fuel via a corresponding fuel injector 46 into a corresponding combustion chamber 24. For the purposes of this disclosure, the “test fuel quantity” refers to a minimum fuel quantity 48 that does not produce a combustion level sufficient to cause a spike in engine output torque and an interruption of the intended coasting of the vehicle 10, as perceived by the driver. The control unit 60 can be configured to detect a fuel pressure 64A in the fuel rail 50 via the fuel pressure sensor 64 while the test quantity 72 of fuel 48 is being injected.The electronic control 60 can also be set up to correlate the determined fuel pressure 64A with the instantaneous angular position θ of the crankshaft 22 in order to determine the time of the command 70 to inject the test quantity 72 of fuel relative to the angular position θ of the crankshaft 22.

[0033] As in Fig. As shown in Figure 3, the control unit 60 is additionally configured to evaluate, with the aid of the internal clock 62, a timing error or delay 74 between the command issued to inject the test quantity 72 of fuel 48 and the actual start 76 of the test quantity fuel injection. The timing delay 74 may indicate a mechanical fault or wear of the injector 46, the injector driver 51, or another device outside the ECU or ECM. Such a timing delay 74 may adversely affect the intended function of the aftertreatment devices in the exhaust system 58 and the exhaust emissions. Therefore, the timing delay 74 is an indicator of the general delay between the commands issued to inject fuel 48 into the combustion chamber 24 and the actual start of the fuel injection 76. The actual start 76 of the fuel injection, i.e.,When a specific fuel injector 46 begins to inject fuel 48 into the combustion chamber 24, this can be detected by a drop 78 in the fuel pressure 64A in the fuel line 50. Accordingly, the control unit 60 can be configured to determine the timing of the command 70 to inject the test quantity 72 of fuel 48 relative to the detected fuel pressure drop 78, in order to evaluate the time delay 74.

[0034] To assess the time delay, the control unit 60 can additionally be configured to identify two consecutive fuel pressure signals via the drop 78, such as signals 80 and 82 (shown in Fig. 3-5) within a scanning window θ Sthe angular position θ of the crankshaft, in the detected fuel pressure 64A. The control 60 can be further programmed to set a distance 84 between the two successive sampled signals 80 and 82 with respect to the angular position θ of the crankshaft 22, i.e., within the sampling window θ S,to determine. Additionally, the control unit 60 can then determine a midpoint 86 between the two successive signals 80 and 82 with respect to the angular position θ of the crankshaft. Accordingly, the midpoint 86 between the two successive signals 80 and 82 of the assessed timing delay 74 is the mean of the distance 80A from the start time of the command 70 to inject the test quantity 72 of fuel at the time of the fuel pressure signal 80 and the distance 82A from the start time of the command 70 to the fuel pressure signal 82. The electronic control unit 60 can be configured to sample and buffer signals indicating the fuel pressure 64A detected by the fuel pressure sensor 64. To ensure a sufficiently narrow sampling window θ STo enable efficient and robust compensation of the time delay 74, the control 60 can be set up to sample the fuel pressure signals 64A at a frequency greater than or equal to 100 times per stroke of the engine 12.

[0035] Mathematically speaking, the ratio between the distances for determining the time delay 74 (to the midpoint 86) in the first step of the compensation strategy is defined as follows: "74"="80A"+"82A"2

[0036] After the first step, the control unit 60 can also be set up to issue the command 70 to inject the test quantity 72 of fuel by half the distance 84 within the sampling window θ. S , specified as a shift of 88 (in Fig. 4 shown), moved forward. The control unit 60 can additionally be configured to assess, after the shift 88 of the command 70 to inject the test quantity 72, whether the drop 78 of the detected fuel pressure 64A remains between the two successive sampled fuel pressure signals 80, 82.

[0037] In the event that the drop 78 of the detected fuel pressure 64A does not remain between the two successive sampled fuel pressure signals 80, 82, i.e., lies outside the two successive fuel pressure signals, the control 60 can additionally correct the determined time change of the command 70 to the midpoint 86 by a quarter of the determined distance 84 between the two successive sampled signals (see Fig. 4) In the event that the drop 78 of the detected fuel pressure 64A remains between the two successive sampled fuel pressure signals 80, 82, the control 60 can adjust the determined change in the timing of the command 70 to the midpoint 86 by one quarter of the determined distance 84 between the two successive sampled signals, i.e., by the amount shown in Fig. Correct the distance of 90° shown in Figure 5 to the rear. Using the compensation technique described above, the control unit 60 can identify new times for issuing command 70, so that the actual fuel injection 48 occurs at the optimal instantaneous position θ of the crankshaft 22. Accordingly, Fig. 4 represents a second step of the compensation strategy, in which the timing of command 70 to inject the test quantity 72 of 88 is shifted forward to compensate for the time delay 74, i.e. a final shift 92 according to Fig. 5. To determine. Mathematically speaking, the ratio between the distances in the second step of the compensation strategy is defined as follows: "92"="74"±("84"4)

[0038] The control unit 60 can additionally be configured to store the compensation for the timing delay 74 thus determined in its non-volatile memory as the final shift 92 in the timing of the command 70 while the motor 12 is operating in zero-torque generation, and then release the command for the final shift 92 during non-zero-torque generation, i.e., positive torque generation by the motor 12. Therefore, the control unit 60 issues the command for the final shift 92 at the time of fuel injection, when the motor 12 is instructed to generate positive torque to drive the vehicle 10.Furthermore, the control unit 60 can be configured to compare the determined final offset 92 with a threshold timing delay 94 and set a diagnostic fault code 96 to inform the operator of vehicle 10 or a service technician if the timing delay compensation thus determined is greater than the threshold timing delay 94. Such a diagnostic fault code 96 can then be used as an indicator that the engine's fuel system and its associated components, such as the injectors 46, may require service or replacement.

[0039] Fig. Section 6 presents a method 100 for operating the compression-ignition engine 12, which is embodied in an algorithm programmed into the electronic control unit 60. The method 100 is specifically designed as a remedy to compensate for a time delay between the commanded fuel injection 48 and the actual commencement of injection, as described above in relation to Fig. 1-5 described. To compensate for such a delay, the procedure 100 involves adjusting the timing of fuel injection into the combustion chamber of the engine 24 as follows. The procedure 100 begins in frame 102 with the detection of the request to generate zero torque by the engine 12 via the control unit 60 in communication with the throttle switch 66.

[0040] Following framework 102, procedure 100 transitions to framework 104. In framework 104, the procedure involves interrupting the supply of fuel 48 via the fuel injector 46 to the combustion chamber 24 during the detected request for zero-torque generation by the engine 12. Accordingly, the operation of procedure 100 is intended to be non-intrusive, i.e., not perceived by the driver and other vehicle occupants, because it is specifically carried out when there is no request for positive torque generation by the engine 12 and while the vehicle 10 is in coasting mode.

[0041] Following on from frame 104, in frame 106 the procedure involves issuing command 70, via the control unit 60, during the detected request for zero-torque generation by the engine 12 at a given crankshaft angular position θ, to inject the test quantity 72 of fuel 48 into the combustion chamber 24. Following frame 106, the procedure proceeds to frame 108. In frame 108, the procedure includes evaluating the time delay 74 between the issued command 70 to inject the test quantity 72 of fuel and the actual commencement 76 of the test quantity injection by the control unit 60. In frame 108, the evaluation of the time delay may also include determining the fuel pressure 64A in the fuel line 50, which is detected via the fuel pressure sensor 64, while the test quantity 72 of fuel is being injected into the combustion chamber 24.

[0042] Within the framework of 108, the procedure can additionally include correlating the determined fuel pressure 64A with the instantaneous angular position θ of the crankshaft 22 via the electronic control 60 in order to determine the timing of the command 70 to inject the test quantity 72 of fuel relative to the angular position of the crankshaft. Furthermore, the evaluation of the timing delay can include determining the timing of the command 70 to inject the test fuel quantity 72 with respect to the drop 78 of the detected fuel pressure 64A, which indicates the start of injection. As above with regard to the Fig. As described in Figures 1-5, the evaluation of the timing delay can further include the identification of two successive fuel pressure signals, e.g., signals 80 and 82, from the fuel pressure sensor 64 via the fuel pressure drop 78 by the electronic control unit 60. Additionally, the assessment of the timing delay in frame 108 can include determining the interval 84 between the two successive sampled signals 80 and 82 within the sampling window θ. S (with respect to the angular position θ of the crankshaft 22) and the center point 86.

[0043] Following frame 108, the procedure proceeds to frame 110, where it involves determining compensation for the assessed time delay 74. Determining the compensation for the assessed time delay 74 may include determining or calculating the offset 88 of the command 70 for injecting the test quantity 72 of fuel into the combustion chamber 24, corresponding to half the distance 84. As part of frame 110, the procedure may also include assessing whether the drop 78 of the detected fuel pressure 64A remains between the two successive fuel pressure signals 80 and 82.

[0044] As in relation to Fig.As described in 1-5, if the drop in the detected fuel pressure 64A lies outside the two consecutive fuel pressure signals 80 and 82, the procedure may include adjusting the time offset 74 of command 70 to inject the test quantity 72 of fuel forward by one-quarter of the determined distance 84. Conversely, if the drop 78 in the detected fuel pressure 64A remains between the two consecutive fuel pressure signals 80 and 82, the procedure may include adjusting the time offset 74 of command 70 backward by one-quarter of the determined distance 84. After frame 110, the procedure may proceed to frame 112, where the procedure may include storing the last offset 92 in the timing of command 70 in the memory of control 60.

[0045] After each of frames 108-112, the procedure can proceed to frame 114 to compare the determined end offset 92 for the time delay 74 with the threshold time delay 94 via the electronic control unit 60 and set a diagnostic fault code 96 if the determined end offset is greater than the threshold time delay. After frame 110 or 112, the procedure proceeds to frame 116. In frame 116, the procedure includes the detection of the request for positive torque generation by the motor 12 by the control unit 60. After frame 116, the procedure proceeds to frame 118, where the procedure includes commanding the end offset 92 in the timing control of the fuel injection into the combustion chamber 24 by the specified compensation after the request for positive torque generation by the motor 12 has been detected.

[0046] Method 100 is intended to compensate for the assessed time delay 74 between a command for fuel injection 48 and the actual commencement of the corresponding fuel injection into the respective combustion chamber 24. Thus, method 100 can counteract the otherwise adverse effects of the timing delay 74 on the intended operation of the aftertreatment devices in the exhaust system 58. Following one of the frames 116-118, the method can be completed in frame 120 or loop back to frame 102 to continue monitoring the throttle position switch 66 and to detect a further request to generate zero torque by the engine 12 via the control unit 60.

[0047] The detailed description and the drawings or illustrations are supporting and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the preferred embodiments and other embodiments for carrying out the claimed disclosure have been described in detail, there are various alternative designs and embodiments for carrying out the disclosure defined in the appended claims. Furthermore, the embodiments shown in the drawings or the features of the various embodiments mentioned in this description are not necessarily to be understood as independent embodiments.Rather, it is possible that each of the features described in one of the exemplary embodiments is combined with one or more other desired features from other embodiments, leading to other embodiments that are not described in words or by reference to the figures. Accordingly, such other embodiments fall within the scope of the appended claims.

Claims

[1] A method (100) for adjusting the timing of fuel injection into a combustion chamber (24) of a compression ignition engine (12), the method (100) comprising: Detect (102), via an electronic control (60), a request to generate zero torque by the motor; Switching off (104), via the electronic control (60), of the fuel supply to the combustion chamber (24) during the detected requirement to generate a torque of zero; Issue (106), via the electronic control (60), a command to inject a test quantity of fuel into the combustion chamber (24) while the detected requirement to generate zero torque exists; Assess (108), via the electronic control (60), a time delay (74) between the command given to inject the test fuel quantity and the start of the injection of the test fuel quantity; Determine (110), via the electronic control (60), a compensation for the assessed time delay (74); Detect (116), via the electronic control (60), a request to generate a positive torque by the motor and commands (118), via the electronic control (60), a shift in the timing of fuel injection into the combustion chamber (24) by the determined compensation during positive torque generation by the engine. [2] The method (100) according to claim 1, wherein the compression ignition engine (12) comprises a crankshaft (22) configured to move a piston (31) back and forth within a cylinder and thereby defines the combustion chamber (24), a high-pressure fuel line configured to supply fuel to the fuel injector (46), a fuel pressure sensor (64) connected to the electronic control unit (60) and configured to detect the fuel pressure in the fuel line, and a crankshaft position sensor (68) connected to the electronic control unit (60) and configured to detect an angular position of the crankshaft (22), wherein the method further comprises: Determine, via the electronic control (60), the fuel pressure in the fuel line while the test fuel quantity is supplied to the fuel injector; and Correlating the determined fuel pressure with the angular position of the crankshaft via the electronic control (60) to determine the timing of the command to inject the test fuel quantity relative to the angular position of the crankshaft. [3] The method (100) according to claim 2, further comprising sampling the fuel pressure signals at a frequency greater than or equal to 100 times per stroke of the compression ignition engine (12). [4] The method (100) according to claim 2, wherein the assessment of the time delay comprises determining the time of the command to inject the quantity of test fuel relative to a drop in the detected fuel pressure. [5] The method (100) according to claim 4, wherein the assessment of the time delay further comprises identifying two successive fuel pressure signals from a fuel pressure sensor via the drop in the detected fuel pressure within a sampling window of the angular position of the crankshaft (22) via the electronic control (60) and determining a distance between the two successive sampled signals with respect to the angular position of the crankshaft (22) and a midpoint of the distance between the two successive sampled signals, and wherein the compensation of the assessed time delay comprises changing the timing of the command to inject the test fuel quantity before the determined midpoint. [6] The method (100) according to claim 5, comprising, after determining the compensation for the assessed time delay, further assessing whether the drop in the detected fuel pressure persists between the two successive fuel pressure signals. [7] The method (100) according to claim 6, wherein the compensation for the assessed time delay further comprises adjusting the modified timing of the command to inject the test fuel quantity forward by one quarter of the determined interval between the two successive fuel pressure signals if the drop in the detected fuel pressure does not remain between the two successive fuel pressure signals. [8] The method (100) according to claim 6, further comprising adjusting the modified timing of the command to inject the test fuel quantity by one quarter of the specified distance to the rear between the two successive fuel pressure signals if the drop in the detected fuel pressure remains between the two successive fuel pressure signals. [9] The method (100) according to claim 1, further comprising comparing, via the electronic control (60), the determined compensation for the assessed time delay via the electronic control with a target threshold time delay and setting, via the electronic control (60), a diagnostic fault code in the motor vehicle if the determined compensation is greater than the target threshold time delay. [10] A motor vehicle engine system comprising: a self-ignition engine (12) configured to generate engine torque, comprising a combustion chamber (24) and a throttle switch (66) configured to request torque generation by the engine; and an electronic control unit (60) that communicates with and is set up with the throttle position switch (66): to identify a requirement for the motor to generate zero torque; to interrupt the fuel supply to the combustion chamber (24) during the detected requirement to generate a torque of zero; to issue a command to inject a quantity of test fuel into the combustion chamber (24) during the detected request to generate zero torque; to assess a time delay (74) between the command given to inject the test fuel quantity and the commencement of the fuel injection of the test quantity; to establish compensation for the identified time delay (74); to recognize a requirement for positive torque generation by the motor; and to command a shift in the timing of fuel injection into the combustion chamber through the determined compensation during the positive torque generation by the engine.

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