FUEL INJECTION SYSTEM AND METHOD FOR OPERATING AN ENGINE

Abstract

A fuel injection system comprises a primary fuel injection system configured to inject fuel into a cylinder of an internal combustion engine using a first injection technique, and a supplementary fuel injection system configured to inject fuel into the cylinder according to a second injection technique, the second injection technique being different from the first injection technique.The system also includes a controller configured to monitor a parameter of a fuel pump connected to the primary fuel injection system and the supplementary fuel injection system, and, based on the parameter being greater than or equal to a parameter threshold, to control a ratio of a first volume of fuel injected by the supplementary fuel injection system to a second volume of fuel injected by the primary fuel injection system during a power engine stroke.

Description

INTRODUCTION

[0001] The present disclosure relates to the field of power engine systems and in particular to fuel injection in power engine systems.

[0002] German patent application DE 10 2017 116 158 A1 describes a method and a system for controlling fuel injection in a vehicle engine. German patent application DE 10 2017 116 568 A1 describes a method for operating a spark-ignition direct-injection internal combustion engine with an exhaust aftertreatment system including a catalyst, and includes monitoring the operating state of the catalyst.

[0003] A fuel injection system injects fuel into an engine using fuel injectors. Fuel injection is typically controlled by an engine control module (ECM) or other controller. A vehicle may contain one or more different types of fuel injectors, such as port fuel injectors and / or direct injectors.

[0004] It is an object of the invention to keep the fuel injection parameters, such as the flow rate and the injection volume, within the capabilities of the vehicle hardware, which includes fuel pumps, during vehicle operation. SUMMARY

[0005] The problem is solved by the features of the independent patent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0006] According to an embodiment of the invention, a fuel injection system comprises a primary fuel injection system configured to inject fuel into a cylinder of an internal combustion engine using a first injection technique, and a supplementary fuel injection system configured to inject fuel into the cylinder using a second injection technique, wherein the second injection technique differs from the first injection technique.The system also includes a controller configured to monitor a parameter of a fuel pump connected to the primary fuel injection system and the supplementary fuel injection system, and, based on the parameter being greater than or equal to a parameter threshold, to control a ratio of a first volume of fuel injected by the supplementary fuel injection system to a second volume of fuel injected by the primary fuel injection system during a power engine stroke.

[0007] In addition to one or more of the features described herein, the primary fuel injection system includes a direct injection device having a first size, and the supplementary fuel injection system includes a direct injection device having a second size, the second size being different from the first size.

[0008] In addition to one or more of the features described here, the primary fuel injection system is a direct injection system and the supplementary fuel injection system is a port fuel injection system.

[0009] In addition to one or more of the features described here, the parameter is a fuel intake volume, which refers to the amount of fuel that the fuel pump draws in.

[0010] In addition to one or more of the features described here, the parameter is an average fuel intake volume to the fuel pump over several engine strokes.

[0011] In addition to one or more of the features described here, the controller is configured to operate the internal combustion engine in a normal mode in which fuel injection is performed using a first value of the ratio, and to operate the internal combustion engine in a supplementary mode in which fuel injection is performed using a second value of the ratio, the second value of the ratio being chosen to cause the parameter to fall below the parameter threshold.

[0012] In addition to one or more of the features described here, fuel injection in normal mode is performed solely by the primary fuel injection system, and fuel injection in supplementary mode is performed solely by the supplementary fuel injection system or by a combination of the primary fuel injection system and the supplementary fuel injection system.

[0013] In addition to one or more of the features described here, the controller is configured to determine the parameter during the supplementation mode and to compare the determined parameter with the parameter threshold.

[0014] In addition to one or more of the features described here, the controller is configured to adjust an airflow to the cylinder based on the specific parameter that is greater than or equal to the parameter threshold during supplementation mode.

[0015] According to a further embodiment of the invention, a method for operating an internal combustion engine comprises providing an air / fuel mixture for the internal combustion engine by injecting a fuel into a cylinder of the internal combustion engine, wherein the injection is carried out by a primary fuel injection system configured to inject the fuel using a first injection technique, and / or a supplementary fuel injection system configured to inject the fuel using a second injection technique.The method also includes monitoring a parameter of a fuel pump connected to the primary fuel injection system and the supplementary fuel injection system, and, based on the parameter being greater than or equal to a parameter threshold, controlling a ratio of a first volume of fuel injected by the supplementary fuel injection system to a second volume of fuel injected by the primary fuel injection system during an engine stroke.

[0016] In addition to one or more of the features described herein, the primary fuel injection system includes a direct injection device having a first size, and the supplementary fuel injection system includes a direct injection device having a second size, the second size being different from the first size.

[0017] In addition to one or more of the features described here, the primary fuel injection system is a direct injection system and the supplementary fuel injection system is a port fuel injection system.

[0018] In addition to one or more of the features described here, the parameter is a fuel intake volume, which refers to the amount of fuel that the fuel pump draws in.

[0019] In addition to one or more of the features described herein, the internal combustion engine is operated according to a normal mode in which fuel injection is carried out using a first value of the ratio, and the internal combustion engine is operated according to a supplementary mode in which fuel injection is carried out according to a second value of the ratio, the second value of the ratio being chosen to cause the parameter to fall below the parameter threshold.

[0020] In addition to one or more of the features described here, fuel injection in normal mode is performed solely by the primary fuel injection system, and fuel injection in supplementary mode is performed solely by the supplementary fuel injection system or by a combination of the primary fuel injection system and the supplementary fuel injection system.

[0021] In addition to one or more of the features described herein, the procedure further includes determining the parameter during the supplementation mode, comparing the determined parameter with the parameter threshold, and, based on the determined parameter being greater than or equal to the parameter threshold, adjusting an airflow to the cylinder.

[0022] According to a non-independently claimed embodiment, a vehicle system comprises an internal combustion engine and a fuel system comprising a primary fuel injection system configured to inject fuel into a cylinder of the internal combustion engine using a first injection technique, and a supplementary fuel injection system configured to inject fuel into the cylinder using a second injection technique, wherein the second injection technique differs from the first injection technique.The vehicle system also includes a controller configured to monitor a parameter of a fuel pump connected to the primary fuel injection system and the supplementary fuel injection system, and, based on the parameter being greater than or equal to a parameter threshold, to control a ratio of a first volume of fuel injected by the supplementary fuel injection system to a second volume of fuel injected by the primary fuel injection system during a power engine stroke.

[0023] In addition to one or more of the features described here, the controller is configured to operate the internal combustion engine in a normal mode in which fuel injection is performed using a first value of the ratio, and to operate the internal combustion engine in a supplementary mode in which fuel injection is performed using a second value of the ratio, the second value of the ratio being chosen to cause the parameter to fall below the parameter threshold.

[0024] In addition to one or more of the features described here, fuel injection in normal mode is performed solely by the primary fuel injection system, and fuel injection in supplementary mode is performed solely by the supplementary fuel injection system or by a combination of the primary fuel injection system and the supplementary fuel injection system.

[0025] In addition to one or more of the features described here, the controller is configured to determine the parameter during supplementation mode, compare the determined parameter with the parameter threshold, and, based on the determined parameter being greater than or equal to the parameter threshold, adjust an airflow to the cylinder.

[0026] The features and advantages described above, and further features and advantages of the disclosure, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Further features, advantages and details appear only as examples in the following detailed description, which refers to the drawings; they show: Fig. 1 a schematic top view of a vehicle according to an exemplary embodiment; Fig. 2 a cross-sectional view of a power engine incorporating a fuel injection system according to an exemplary embodiment; Fig. 3 a flowchart illustrating, according to an exemplary embodiment, aspects of a method for controlling an internal combustion engine; and Fig. 4 a computer system according to an exemplary embodiment. DETAILED DESCRIPTION

[0028] The following description is merely exemplary and is not intended to limit the present disclosure, its application, or uses. It should be understood that, throughout the drawings, corresponding reference numerals denote similar or corresponding sections and features.

[0029] According to exemplary embodiments, a fuel injection system for an internal combustion engine and associated methods are provided. One embodiment of a propulsion system comprises a primary fuel injection system and a supplementary fuel injection system. A controller is configured to monitor one or more components of the propulsion system, such as a fuel pump, and to compare a parameter relating to fuel injection and / or propulsion (e.g., a pump intake volume) with a parameter threshold (e.g., a maximum pump capacity or a maximum intake volume).

[0030] Based on the parameter that is greater than or equal to the parameter threshold, the controller switches the engine from normal mode to supplemental mode. In normal mode, fuel injection is provided exclusively by the primary fuel injection system, or fuel is injected using an initial ratio of supplemental to primary fuel injection. In supplemental mode, the controller activates the supplemental fuel injection system and / or adjusts the ratio so that fuel injection can continue without exceeding the capacity of a fuel pump and / or one or more other components.

[0031] The embodiments described here offer numerous advantages and technical benefits. They provide improvements in the efficiency and performance of internal combustion engines. For example, they ensure that sufficient fuel is supplied under any given condition, while also ensuring that fuel system components, such as high-pressure fuel pumps, remain within their operating limits. Furthermore, these embodiments enable fuel systems that are undersized for all environmental conditions (e.g., fuel pumps smaller than those used in conventional fuel injection systems). By enabling an undersized fuel system, emissions are improved, and the resources required to design a fuel system and camshaft assembly are reduced.

[0032] The embodiments are not limited to use with a specific vehicle and can be applicable to various contexts. For example, embodiments can be used with automobiles, trucks, construction equipment, power tools, motorcycles, boats, aircraft and / or other devices or systems that incorporate a fuel-injected power engine or engines.

[0033] Fig. Figure 1 shows an embodiment of a motor vehicle 10 comprising a vehicle body 12, which at least partially defines a passenger compartment 14. The vehicle body 12 also carries various vehicle subsystems, including a propulsion system 16 and further subsystems to support functions of the propulsion system 16, as well as other vehicle components such as a braking subsystem, a suspension system, a steering subsystem, and others. If the vehicle 10 is an internal combustion engine vehicle or a hybrid electric vehicle, further vehicle components include a fuel injection subsystem, an exhaust system, and others.

[0034] For example, vehicle 10 is a hybrid vehicle in which the propulsion system 16 includes an internal combustion engine 18 for generating torque and other components for supporting engine operation, such as a cooling system 20. The engine 18 is connected to a transmission system 22 for controlling the transmission of torque from the engine 18 to a front drive shaft 24, which is connected to front wheels 26. The propulsion system 16 may also include an electric drive system comprising at least one electric motor 28 connected to a high-voltage battery pack (HV battery pack) 30.

[0035] The 16-stage thrust system is not limited to the configuration shown in Fig. Figure 1 shows that any number of propulsion devices may be present. For example, the vehicle 10 may include an engine and / or an internal combustion engine (in addition to or instead of the power unit 18 and the engine 28) connected to a rear drive shaft 32 and rear wheels 34.

[0036] One or more processing devices are included to control the operation of the propulsion system 16. In one embodiment, a controller 40, such as a power machine control unit (ECU), is configured to receive torque requests and control the power machine 18.

[0037] The vehicle 10 also includes a computer system 50, which comprises one or more processing units 52 and a user interface 54. The computer system 50 can communicate with the controller 40 (e.g., the ECU) and / or one or more other processors to, for example, send instructions to it in response to user input (e.g., torque instructions). The various processing units, modules, and units can communicate with each other via a communication device or system, such as a CAN bus or a TCP bus.

[0038] Fig. Figure 2 shows an embodiment of the propulsion system 16. According to this embodiment, the propulsion system 16 includes a fuel injection system comprising a primary injection system and a secondary or supplementary injection system. The primary and supplementary injection systems can use the same type of fuel injection or different types of fuel injection.

[0039] For example, the engine 18 is a spark-ignition engine containing several cylinders 60, each of which takes in an air-fuel mixture for combustion. Air can be taken in via an intake manifold 62 and controlled by a throttle valve or a valve 64, which can be controlled by the controller 40, to regulate the airflow (represented by arrow A) into the intake manifold 62.

[0040] Each cylinder 60 is coupled to a spark plug 66 and an intake valve 68 to draw in air or an air-fuel mixture. The intake valve positions are regulated by an intake camshaft 70. Each cylinder 60 is also coupled to an exhaust valve 72 to remove combustion gases (indicated by arrow E).

[0041] A power engine crankshaft (not shown) rotates at the engine speed or at a rate proportional to the engine speed. It may include a crankshaft sensor 74 to enable the controller 40 to determine the position of the crankshaft during power engine operation.

[0042] The engine 18 contains a fuel system comprising two fuel injection systems. The fuel injection systems are configured to supply fuel to the cylinders 60 using different injection techniques. The injection systems are in fluid communication with a fuel tank 76 and a high-pressure pump 78.

[0043] According to one embodiment, the fuel system comprises a primary fuel injection system 80 and a supplementary fuel injection system 90. Each fuel injection system is configured to inject fuel using a different injection technique. For example, the fuel injection systems may use the same type of injection (e.g., direct injection or port injection) but have different parameters, such as different injector device sizes, which allow for different flow rates.

[0044] As in Fig. As shown in Figure 2, the primary fuel injection system 80 is configured as a direct injection (DI) system, with fuel being injected directly into each cylinder 60 using direct fuel injection technology. The supplementary fuel injection system 90 is configured as a port fuel injection (PFI) system, with fuel being injected using PFI technology. In this example, the PFI technology involves injecting fuel into the intake manifold 62 to mix with air before an air-fuel mixture is delivered to each cylinder 60.

[0045] The primary fuel injection system 80 includes a primary fuel distributor 82 in fluid communication with a direct injection device 84 coupled to each cylinder 60. The primary fuel distributor 82 is configured to supply pressurized fuel from the pump 78 to each direct injection device 84. A primary fuel valve 86 can be controlled by the controller 40 to adjust the fuel flow rate.

[0046] The supplementary fuel injection system 90 includes a supplementary fuel distributor 92 configured to direct pressurized fuel from the pump 78 to a port fuel injector 94 assigned to each cylinder 60. A supplementary fuel valve 96 can be controlled by the controller 40 to adjust the fuel flow rate through the fuel distributor 92 (and / or to activate and deactivate the supplementary fuel injection system 90).

[0047] It should be noted that the primary fuel valve 86 and the supplementary fuel valve 96 can be operated to adjust a relative amount of fuel supplied by each injection system, and / or can be operated as a switch to activate or deactivate one of the injection systems. For example, the primary fuel valve 86 and / or the supplementary fuel valve 96 can be controlled to provide a ratio of a volume of fuel supplied by the supplementary fuel injection system 90 (a supplementary fuel volume) to a volume of fuel supplied by the primary fuel injection system 80 (a primary fuel volume).

[0048] The engine 18 can be operated in several fuel injection modes. For example, the engine 18 can be operated in a normal mode in which fuel injection is carried out using an initial ratio of the supplementary fuel volume (e.g., injected by the port fuel injection) to the primary fuel volume (e.g., injected by the direct injection). This ratio is referred to as the "injection ratio" and is defined as the ratio of a volume of fuel injected during a stroke by the supplementary fuel injection system 90 to a volume of fuel injected during the stroke by the primary fuel injection system 80.

[0049] Normal mode can use either primary fuel injection (i.e., the ratio is zero) or a selected proportion of the total fuel volume injected by supplemental injection. For example, in normal mode, valve 96 is closed and valve 86 is open, such that fuel is injected only through the primary fuel injection system 80. In another example, normal mode uses an initial or first injection ratio, and supplemental mode uses a second injection ratio that differs from the initial or first injection ratio.

[0050] Fig. Figure 3 shows embodiments of a method 100 for controlling an internal combustion engine. Aspects of the method 100 can be performed by the controller 40 or another suitable processing device.

[0051] Method 100 is used for illustration in conjunction with the engine 18 and the fuel injection systems of Fig. 2 described. Embodiments are not so restricted, since the method 100 can be carried out in connection with any suitable vehicle or drive system that has dual injection capabilities.

[0052] Procedure 100 comprises a number of steps or stages represented by blocks 101-108. Procedure 100 is not limited to the number or order of its steps, as some steps represented by blocks 101-108 may be performed in a different order than described below, or fewer than the total number of steps may be performed.

[0053] In block 101, vehicle 10 is running and engine 18 is engaged. At this point, engine 18 is in normal mode. In normal mode, the supplementary fuel injection system 90 is inactive, and fuel injection is performed exclusively by the primary fuel injection system 80. Alternatively, in normal mode, both injection systems are active and operate according to an initial injection ratio. The initial injection ratio is determined based on factors such as engine speed and load.

[0054] In block 102, pump 78 (and / or another component of the engine 18 or the fuel system) is monitored to determine whether a trigger condition is met. For example, factors such as temperature changes, load changes, and changes in ignition timing are monitored and compared with system limits.

[0055] Controller 40 determines whether the factors are within the system limits. If the factors are within the system limits, procedure 100 ends in block 108 and fuel injection continues in normal mode. If the factors meet or exceed the system limits, the trigger condition is met and procedure 100 continues with block 103.

[0056] When the trigger condition in block 103 is met (i.e., a system or hardware constraint is satisfied), a parameter relating to fuel injection and / or engine operation is monitored and compared to a parameter threshold. The parameter may relate to the engine, such as rotational speed or torque. According to one embodiment, the parameter relates to the fuel flow to engine 18.

[0057] When determining the parameter, it is compared to the parameter threshold. If the parameter does not meet or exceed the parameter threshold, the normal mode is maintained.

[0058] For example, pump 78 is monitored to measure or estimate its volume requirement (i.e., the volume of fuel consumed) per cycle. The estimated volume requirement is then compared to the maximum volume capacity of pump 78.

[0059] According to one embodiment, an average of the volume requirement is calculated over several cycles. This averaging is useful in situations where the number of rotary pistons in the pump 78 does not match the number of cylinders 60.

[0060] In block 104, controller 40 determines whether the parameter (e.g., the estimated volume requirement for one cycle or the average volume requirement) is still greater than or equal to the parameter threshold. If the parameter is no longer greater than or equal to the parameter threshold, procedure 100 ends in block 108 and fuel injection continues in normal mode.

[0061] If the parameter in block 105 is still greater than or equal to the parameter threshold (e.g., the volume requirement still meets or exceeds the maximum volume capacity), the power unit 18 is put into supplementary mode, in which the ratio is set (or the primary fuel injection is blocked and the supplementary fuel injection is enabled).

[0062] According to one embodiment, the original injection ratio is adjusted. For example, the average volume requirement is used to calculate a new injection ratio. The original ratio is adjusted by increasing the relative volume of fuel injected by the supplementary fuel injection system 90 to achieve the new injection ratio.

[0063] In block 106, controller 40 determines whether the parameter continues to meet or exceeds the parameter threshold while the new injection ratio is applied. For example, controller 40 continues fuel injection using the new injection ratio and measures the volume requirement of pump 78.

[0064] If the new injection ratio causes the volume requirement (or any other parameter) to be within the parameter threshold, procedure 100 ends and fuel injection continues according to the new injection ratio.

[0065] If the volume requirement or another parameter in block 107 still meets or exceeds the parameter threshold, the controller 40 causes the airflow to be limited (e.g., by controlling the valve or throttle valve 64). The controller 40 continues monitoring the engine 18 and returns the airflow to its previous level when the fuel requirement falls back to the parameter threshold. If the fuel requirement continues to decrease, the engine 18 can be returned to normal operation.

[0066] Fig.Figure 4 illustrates aspects of an embodiment of a computer system 140 that can perform various aspects of the embodiments described herein. The computer system 140 includes at least one processing device 142, which generally contains one or more processors for performing aspects of image acquisition and analysis procedures described herein.

[0067] Components of the computer system 140 include the processing device 142 (such as one or more processors or processing units), a memory 144, and a bus 146 that connects various system components containing the system memory 144 to the processing device 142. The system memory 144 can be a non-transient, computer-readable medium and can contain a variety of computer-system-readable media. Such media can be any available media accessible through the processing device 142 and include both volatile and non-volatile media, as well as removable and non-removable media.

[0068] For example, the system memory 144 contains non-volatile memory 148 such as read-only memory (ROM) and may also contain volatile memory 150 such as read / write memory (RAM) and / or a buffer. The computer system 140 may also contain other removable / non-removable volatile / non-volatile computer system storage media.

[0069] System memory 144 can contain at least one program product that has a set (e.g., at least one) of program modules configured to perform functions of the embodiments described herein. For example, system memory 144 stores various program modules that generally perform the functions and / or methodologies of embodiments described herein. One or more modules 152 may be included to perform functions discussed herein. System 140 is not so restricted, as it may contain further modules.As the term "module" is used here, it refers to a processing circuit arrangement that may include an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or grouped) with memory that executes one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality.

[0070] The processing device 142 can also communicate with one or more external devices 156, such as a keyboard, a pointing device, and / or any other devices (e.g., a network card, a modem, etc.), which enable the processing device 142 to communicate with one or more other computing devices. Communication with different devices can be effected via input / output interfaces (I / O interfaces) 164 and 165.

[0071] The processing device 142 can also communicate with one or more networks 166, such as a local area network (LAN), a wide area network (WAN), a bus network, and / or a public network (e.g., the Internet), by means of a network adapter 168. It should be understood that other hardware and / or software components may be used in conjunction with the computer system 140, although they are not shown. Examples include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrangements, RAID systems, and data archiving storage systems, etc.

[0072] The terms "a" and "an" do not denote a limit on the number of elements, but rather indicate the presence of at least one of the referenced element. The term "or" means "and / or" unless clearly indicated otherwise by context. A reference to "an aspect" in the application text means that a specific element (e.g., a feature, a structure, a step, or a property) described in connection with that aspect is contained in at least one aspect described therein and may or may not be present in other aspects. It should also be understood that the described elements in the various aspects may be combined in any suitable manner.

[0073] When an element, such as a layer, a thin layer, an area, or a substrate, is described as "attached" to another element, it may be located directly adjacent to that element, or there may be intervening elements. Conversely, when an element is described as "directly adjacent" to another element, there are no intervening elements.

[0074] Unless otherwise specified herein, all testing standards shall be the most recent valid standard as of the filing date of this application or, if priority is claimed, as of the filing date of the earliest priority application in which the testing standard appears.

[0075] Unless otherwise defined, technical and scientific terms used herein have the same meaning as would normally be understood by a person skilled in the field to which this disclosure belongs.

Claims

[1] Fuel injection system comprising: a primary fuel injection system (80) configured to inject fuel into a cylinder (60) of an internal combustion engine (18) using a first injection technique; a supplementary fuel injection system (90) configured to inject fuel into the cylinder (60) according to a second injection technique, wherein the second injection technique differs from the first injection technique; and a controller (40) configured to monitor a parameter of a fuel pump (78) connected to the primary fuel injection system (80) and the supplementary fuel injection system (90) and, based on the parameter being greater than or equal to a parameter threshold, to control a ratio of a first volume of fuel injected by the supplementary fuel injection system (90) to a second volume of fuel injected by the primary fuel injection system (80) during a power engine cycle. [2] System according to claim 1, wherein the primary fuel injection system (80) includes a direct injection device having a first size, and the supplementary fuel injection system (90) includes a direct injection device having a second size, wherein the second size is different from the first size. [3] System according to claim 1, wherein the primary fuel injection system (80) is a direct injection system and the supplementary fuel injection system (90) is a port fuel injection system. [4] System according to claim 1, wherein the parameter is a fuel intake volume which relates to a quantity of fuel that is drawn in by the fuel pump (78). [5] System according to claim 1, wherein the parameter is an average fuel intake volume to the fuel pump (78) over several engine cycles. [6] System according to claim 1, wherein the controller (40) is configured to operate the internal combustion engine (18) in a normal mode in which fuel injection is carried out using a first value of the ratio, and to operate the internal combustion engine (18) in a supplementary mode in which fuel injection is carried out using a second value of the ratio, wherein the second value of the ratio is selected to cause the parameter to fall below the parameter threshold. [7] System according to claim 6, wherein in normal mode the fuel injection is carried out solely by the primary fuel injection system (80) and in supplementary mode the fuel injection is carried out solely by the supplementary fuel injection system (90) or by a combination of the primary fuel injection system (80) and the supplementary fuel injection system (90). [8] System according to claim 6, wherein the controller (40) is configured to determine the parameter during the supplementation mode and to compare the determined parameter with the parameter threshold. [9] System according to claim 8, wherein the controller (40) is configured to adjust an airflow (A) to the cylinder (60) based on the specified parameter which is greater than or equal to the parameter threshold during the supplementation mode. [10] Method for operating an internal combustion engine (18) comprising: Providing an air / fuel mixture for the internal combustion engine (18) by injecting a fuel into a cylinder (60) of the internal combustion engine (18), wherein the injection is carried out by a primary fuel injection system (80) configured to inject the fuel using a first injection technique, and a supplementary fuel injection system (90) configured to inject the fuel using a second injection technique, wherein the second injection technique differs from the first injection technique; Monitoring a parameter of a fuel pump (78) connected to the primary fuel injection system (80) and the supplementary fuel injection system (90); and Controls based on the parameter being greater than or equal to a parameter threshold, a ratio of a first volume of fuel injected by the supplementary fuel injection system to a second volume of fuel injected by the primary fuel injection system (80) during an engine stroke.

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