Fuel control system for internal combustion engine having multiple injection systems

Abstract

The fuel system includes a first fuel rail. A first fuel delivery system including a first plurality of fuel injectors is connected to the first fuel rail. A first plurality of fuel injectors inject an amount of fuel into a first portion of the engine. The second fuel rail has a second fuel delivery system including a second plurality of fuel injectors. A second plurality of fuel injectors inject an amount of fuel into a second portion of the engine different from the first portion. And a controller operably connected to the first fuel delivery system and the second fuel delivery system, the controller configured to control the first fuel delivery system and the second fuel delivery system. Operation of the first and second fuel delivery systems is selectively enabled and disabled based on one of a detected temperature and a detected pressure of fuel delivered to respective ones of the first and second plurality of fuel injectors.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of fuel control systems, and more specifically, to a fuel control system for an internal combustion engine having multiple injection systems. BACKGROUND

[0002] Internal combustion engines include a fuel system that combines liquid fuel with air to form a combustible mixture. The combustible mixture is introduced into a cylinder, compressed, and ignited to form a pressurized gas. The pressurized gas moves a piston in the cylinder to generate energy to power a vehicle. In some cases, the fuel system can include a carburetor that introduces fuel into a manifold to combine with air. In other cases, the fuel system can include fuel injectors that create an atomized explosion of the air-fuel mixture into the cylinder.

[0003] In some cases, the fuel injectors can be arranged to deliver atomized fuel into a manifold leading to the cylinder. In other cases, the injectors can introduce fuel directly into the cylinder. In other cases, the engine can include a first fuel delivery system including injectors that deliver fuel into a manifold and a second fuel delivery system including injectors that deliver fuel directly into the cylinder. One fuel system can operate during idle and the other fuel system can operate when the vehicle is in motion.

[0004] If the fuel system operating at idle is run for an extended period of time, the engine temperature and / or fuel pressure can exceed desired parameters. Increasing the engine temperature and / or fuel pressure can decrease the overall operational efficiency of the vehicle and can also place strain on certain engine components. Therefore, it is desirable to provide a system for controlling the operation of the first and second fuel delivery systems in order to maintain the temperature and / or fuel pressure within selected operating parameters. SUMMARY

[0005] In one example embodiment, a fuel system includes a first fuel rail configured to be connected to a fuel source. A first fuel delivery system including a first plurality of fuel injectors is connected to the first fuel rail. The first plurality of fuel injectors is configured to inject an amount of fuel into a first portion of an internal combustion engine. A second fuel rail is configured to be connected to the fuel source. A second fuel delivery system including a second plurality of fuel injectors is connected to the second fuel rail. The second plurality of fuel injectors is configured to inject an amount of fuel into a second portion of the internal combustion engine, the second portion being different than the first portion. A controller is operably connected to the first fuel delivery system and the second fuel delivery system. The controller is configured to selectively enable and disable operation of the first fuel delivery system and the second fuel delivery system based on one of a sensed temperature and a sensed pressure of fuel delivered to respective fuel injectors of the first plurality of fuel injectors and the second plurality of fuel injectors.

[0006] In addition to one or more of the features described herein, the fuel system includes a first pressure sensor and a first temperature sensor mounted in the first fuel rail and a second temperature sensor and a second pressure sensor mounted in the second fuel rail.

[0007] In addition to one or more of the features described herein, the first plurality of fuel injectors is configured to inject fuel upstream of an intake valve of the internal combustion engine.

[0008] In addition to one or more of the features described herein, the second plurality of fuel injectors is configured to inject an amount of fuel directly into a cylinder of the internal combustion engine downstream of the intake valve.

[0009] In addition to one or more of the features described herein, the controller is configured to disable the second fuel delivery system during a selected operating period of the internal combustion engine.

[0010] In addition to one or more of the features described herein, the controller is configured to enable both the first fuel delivery system and the second fuel delivery system if one of a temperature sensed in the first fuel rail and a pressure sensed in the second fuel rail exceeds a selected value.

[0011] In another example embodiment, a vehicle includes a body defining a passenger cabin. A plurality of wheels support the body. An internal combustion engine is supported in the body and is operably connected to at least one of the plurality of wheels. The internal combustion engine includes a plurality of cylinders, an intake system including an intake plenum, and an intake valve selectively connecting the intake system to at least one of the plurality of cylinders. A fuel system is fluidly connected to the internal combustion engine and includes a first fuel rail configured to be connected to a fuel source. A first fuel delivery system including a first plurality of fuel injectors is connected to the first fuel rail. The first plurality of fuel injectors is configured to inject an amount of fuel into a first portion of the internal combustion engine. A second fuel rail is configured to be connected to the fuel source. A second fuel delivery system including a second plurality of fuel injectors is connected to the second fuel rail. The second plurality of fuel injectors is configured to inject an amount of fuel into a second portion of the internal combustion engine different from the first portion. A controller is operably connected to the first plurality of fuel injectors and the second plurality of fuel injectors. The controller is configured to selectively enable and disable operation of the first fuel delivery system and the second fuel delivery system based on one of a sensed temperature and a sensed pressure of fuel delivered to respective fuel injectors of the first plurality of fuel injectors and the second plurality of fuel injectors.

[0012] In addition to one or more of the vehicle features described herein, the fuel system further includes a first pressure sensor and a first temperature sensor mounted in the first fuel rail and a second temperature sensor and a second pressure sensor mounted in the second fuel rail.

[0013] In addition to one or more of the vehicle features described herein, the first plurality of fuel injectors is configured to inject fuel into the intake plenum of the intake valve.

[0014] In addition to one or more of the vehicle features described herein, the second plurality of fuel injectors is configured to inject an amount of fuel directly into each of the plurality of cylinders.

[0015] In addition to one or more of the vehicle features described herein, the controller is configured to disable the second fuel delivery system during a selected operating period of the internal combustion engine.

[0016] In addition to one or more of the vehicle features described herein, the controller is configured to enable both the first fuel delivery system and the second fuel delivery system if one of a temperature sensed in the first fuel rail and a pressure sensed in the second fuel rail exceeds a selected value.

[0017] In yet another example embodiment, a method of operating a plurality of fuel injection systems for supporting an internal combustion engine in a vehicle includes injecting fuel into a first portion of the internal combustion engine by a first plurality of fuel injectors and injecting fuel into a second portion of the internal combustion engine different from the first portion by a second plurality of fuel injectors. The method further includes detecting an operating mode of the vehicle, disabling the first plurality of fuel injectors based on the operating mode of the vehicle, detecting one of a temperature and a pressure of fuel at the first plurality of fuel injectors, and enabling the first plurality of fuel injectors if the one of the temperature and the pressure of fuel exceeds a selected threshold.

[0018] In addition to one or more of the steps described herein, wherein enabling the first plurality of fuel injectors includes detecting that a temperature of fuel at each fuel injector of the first plurality of fuel injectors exceeds a selected temperature threshold.

[0019] In addition to one or more of the steps described herein, wherein enabling the first plurality of fuel injectors includes detecting that a temperature of fuel at each fuel injector of the first plurality of fuel injectors exceeds a selected temperature threshold.

[0020] In addition to one or more of the steps described herein, wherein enabling the first plurality of fuel injectors includes detecting that a pressure of fuel at each fuel injector of the first plurality of fuel injectors exceeds a selected pressure threshold.

[0021] In addition to one or more of the steps described herein, wherein enabling the first plurality of fuel injectors when the pressure of fuel at the first plurality of fuel injectors exceeds the selected pressure threshold includes delivering fuel into the internal combustion engine without enabling a fuel pump.

[0022] In addition to one or more of the steps described herein, wherein enabling the first plurality of fuel injectors when the pressure of fuel at the first plurality of fuel injectors exceeds the selected pressure threshold includes delivering fuel into the internal combustion engine without enabling the fuel pump includes delivering no more than 3 fuel injections into the internal combustion engine.

[0023] In addition to one or more of the steps described herein, the method further includes determining that the one of the temperature and the pressure of fuel at the first plurality of fuel injectors has fallen below the selected threshold, and disabling the first plurality of fuel injectors.

[0024] In addition to one or more of the steps described herein, the method further includes detecting an operating mode of the vehicle prior to disabling the first plurality of fuel injectors, and disabling the first plurality of fuel injectors if the operating mode indicates that the vehicle is at idle.

[0025] The above features and advantages of the present disclosure, and other features and advantages, are readily apparent from the following detailed description, when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] Other features, aspects, and details are described below with reference to the drawings. The drawings are provided and are part of this specification and exhibit:

[0027] Figure 1 is a left side view of a vehicle including an internal combustion engine and a fuel control system according to a non-limiting example;

[0028] Figure 2 is a partial cutaway view of an internal combustion engine of Figure 1 including a fuel system having multiple injection systems according to a non-limiting example;

[0029] Figure 3 is a schematic view of a fuel control system of Figure 2 the internal combustion engine according to a non-limiting example; and

[0030] Figure 4 is a flowchart illustrating a method of controlling fuel delivery by Figure 3 the fuel system according to a non-limiting example. DETAILED DESCRIPTION

[0031] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. As used herein, the term module refers to processing circuitry, which can include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality.

[0032] According to a non-limiting example, a vehicle is generally indicated at 10 in Figure 1 The vehicle 10 includes a vehicle body 12 supported on a plurality of wheels 16. The vehicle body 12 partially defines a passenger cabin 20 having a seat 23 positioned behind an instrument panel 26. The vehicle 10 includes an internal combustion engine (ICE) 34 that provides power to one or more of the plurality of wheels 16.

[0033] Reference is made to Figure 2The ICE engine 34 includes an engine cylinder 40 that includes a plurality of cylinders, one of which is indicated at 42. The engine cylinder 40 supports a crankshaft 44 that in turn supports a connecting rod 46 that is connected to a piston 48. When the crankshaft 44 rotates, the piston 48 reciprocates within the cylinder 42. A cylinder head 54, including an intake system 56, is connected to the engine cylinder 40. The cylinder head 54 supports a first camshaft 58a and a second camshaft 58b that rotate to open intake valves 60 and exhaust valves 62. Springs (not separately labeled) associated with the intake valves 60 and the exhaust valves 62 provide closing force to the valves.

[0034] The ICE engine 34 includes a combustion chamber 64 defined between the piston 48 and the cylinder head 54. A spark plug 66 disposed in the cylinder head 54 selectively ignites a combustible mixture to move the piston 48. In some cases, the combustible mixture is formed in an intake plenum 70 of the intake system 56 and enters the combustion chamber 64 through the intake valves 60. The exhaust gases formed after combustion exit the combustion chamber 64 as exhaust 63 through the exhaust valves 62. In other cases, the combustible mixture is introduced directly into the combustion chamber 64. In each case, a fuel system 80 produces the combustible mixture by delivering atomized fuel sprays 83 and 84 into the ICE 34.

[0035] In describing the fuel system 80 according to non-limiting examples, reference will now be made in continuing reference to Figure 2 , with reference to Figure 3 . The fuel system 80 includes a first fuel delivery system 82 defined by a first plurality of fuel injectors 84 and a second fuel delivery system 86 defined by a second plurality of fuel injectors 88. The first plurality of fuel injectors 84 and the second plurality of fuel injectors 88 are configured to introduce fuel into different portions of the ICE engine 34, as will be described in greater detail herein. In one non-limiting example, the first plurality of fuel injectors 84 are mounted to the intake system 56 upstream of the intake valves 60 and the second plurality of fuel injectors 88 are mounted to the cylinder head 54 and positioned to introduce an amount of fuel directly into the combustion chamber 64.

[0036] In the non-limiting example, the first plurality of fuel injectors 84 are connected to a first fuel rail 90 and the second plurality of fuel injectors 88 are connected to a second fuel rail 92. The first fuel rail 90 includes a first inlet 94 and a second inlet 96 and the second fuel rail 92 includes a third inlet 97. At this point, it should be understood that the number and location of inlets can vary, as can the specific location of the first fuel rail 90 and the second fuel rail 92. Regardless of the configuration, the first fuel rail 90 and the second fuel rail 92 are fluidly connected to a source 99 of fuel 100.

[0037] The fuel pump 104 is fluidly connected between the fuel source 100 and the first and second fuel rails 90, 92. The fuel pump 104 delivers a pressurized flow of fuel into each fuel rail 90, 92 for injection into the combustion chamber 64 through the first plurality of fuel injectors 84 and / or the second plurality of fuel injectors 86 as needed. In a non-limiting example, a first temperature sensor 108 is disposed in the first fuel rail 90 and a second temperature sensor 110 is disposed in the second fuel rail 92. Further, a first pressure sensor 114 is disposed in the first fuel rail 90 and a second pressure sensor 116 is disposed in the second fuel rail 92.

[0038] The first and second temperature sensors 108 / 110 and the first and second pressure sensors 114 / 116 provide feedback to the fuel control system 120 for injecting fuel from the first plurality of fuel injectors 84 and / or the second plurality of fuel injectors 88. The fuel control system 120 includes a controller having a central processing unit (CPU) 122, a non-volatile memory 124, a temperature assessment module 126, and a pressure assessment module 128. While shown as co-located, the components of the controller 120 can be disposed in different areas of the vehicle 10. Further, while shown as separate modules, the temperature assessment module 126 and the pressure assessment module 128 can be disposed in a single combined temperature / pressure assessment module.

[0039] Reference will now be made to Figure 4 which describes a method 200 of controlling fuel delivery into the combustion chamber 64 through the first plurality of fuel injectors 84 and the second plurality of fuel injectors 86. The method 200 is initiated in block 210. At this time, in block 212, it is determined whether both the first plurality of fuel injectors 84 and the second plurality of fuel injectors 88 are running. In an example, the controller 120 can determine the mode of operation of the vehicle 10. In a non-limiting example, during an idle period, the first plurality of fuel injectors 84 can be running and the second plurality of fuel injectors 88 can be non-running. As such, fuel is delivered into the combustion chamber 64 through the intake valve 60 only.

[0040] If both the first plurality of fuel injectors 84 and the second plurality of fuel injectors 88 are running, the method 200 ends at block 214. If only one of the first plurality of fuel injectors 84 and the second plurality of fuel injectors 88 is running, such as during an idle period, the temperature assessment module 126 reads the second temperature sensor 110 at block 220 to determine the temperature in the second fuel rail 92. The sensed temperature is compared to a temperature threshold stored in the non-volatile memory 124. If the temperature in the second fuel rail 92 is within the specified temperature limit, the method 200 moves to block 222.

[0041] In block 222, the pressure assessment module 128 reads the second pressure sensor 116 to determine the fuel pressure in the second fuel rail 92. The sensed pressure is compared to a pressure threshold stored in the non-volatile memory 124. If the fuel pressure in the second fuel rail 92 is within the specified pressure limit, the method 200 moves to block 214 and ends. The method 200 can be repeated continuously or at selected intervals depending on the operating mode, operating temperature, and ambient temperature of the vehicle 10. For example, the method 200 can be repeated more frequently during idle in hot climates and less frequently during highway driving in cold climates.

[0042] In a non-limiting example, if the sensed temperature in block 220 is above the prescribed temperature limit stored in the non-volatile memory 124, the method 200 moves to block 230 to re-enable the second plurality of fuel injectors 88. The controller 120 can enable the fuel pump 104 to facilitate ten (10) or more injections of fuel through the second plurality of fuel injectors 88 to reduce the temperature in the second fuel rail 92. At block 240, the temperature assessment module 126 again samples the second temperature sensor 110 to determine the effect of the injections on the fuel temperature in the second fuel rail 92. If the fuel temperature has dropped below the prescribed limit, the method 200 moves to block 214 and ends. If, on the other hand, the fuel temperature remains elevated, the method 200 returns to block 230. At this point, the fuel pump 104 is again enabled and the second plurality of fuel injectors is re-enabled to facilitate additional fuel injections. This control loop is repeated until the fuel temperature in the second fuel rail 92 is within the prescribed limit.

[0043] In a non-limiting example, if the sensed temperature in block 220 is within the prescribed temperature limit stored in the non-volatile memory 124, but the pressure assessment module 128 determines that the sensed pressure in block 222 is outside the prescribed pressure limit stored in the non-volatile memory 124, the method 200 moves to block 230 to re-enable the second plurality of fuel injectors 88. In this case, the controller 120 can only enable the second plurality of fuel injectors 88 to facilitate one or two (1 or 2) fuel injections. Thus, the fuel pump 104 can not need to be enabled in order to reduce the pressure in the second fuel rail 92 when the sensed pressure is outside the stored pressure limit.

[0044] The pressure evaluation module 128 again samples the second temperature sensor 110 to determine the effect of the injection on the fuel pressure in the second fuel rail 92. If the fuel pressure has dropped below a prescribed limit, the method 200 proceeds to block 214 and ends. If, on the other hand, the fuel pressure remains elevated, the method 200 returns to block 230. The second plurality of fuel injectors are re-enabled to facilitate additional fuel injection. The control loop is repeated until the fuel pressure in the second fuel rail 92 is within the prescribed limits.

[0045] At this time, it should be understood that the non-limiting examples described herein provide a system for controlling an internal combustion engine having multiple injection systems to mitigate pressure and temperature parameters in a fuel supply rail. Maintaining the temperature and pressure within prescribed limits can protect pressure relief components. That is, when the temperature and pressure of the fuel in the fuel rail is within the limits, there is no need to enable a pressure relief valve. Reducing the number of times a pressure relief valve is enabled increases the overall operational life of the components. Further, while described in terms of disabling a second plurality of fuel injectors (e.g., direct injection injectors), the method can also control the operation of indirect injection.

[0046] The term “a” does not denote a limitation of quantity, but rather is used to mean that at least one of the referenced items is present. The term “or” means “and / or” unless explicitly stated otherwise. References throughout this specification to “aspects” mean that a particular element described can be included in the at least one aspect and can or can not be present in other aspects. Additionally, it is to be understood that the described elements can be combined in any suitable manner in the various aspects.

[0047] When an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements can also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

[0048] The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ± 8% of a given value.

[0049] Unless otherwise stated, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

[0050] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0051] While the foregoing disclosure has been described in reference to exemplary embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope thereof. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed, but will include all embodiments falling within the scope of the disclosure.

Claims

1. A fuel system comprising: a first fuel rail configured to connect to a fuel source; a first fuel delivery system comprising a first plurality of fuel injectors connected to the first fuel rail, the first plurality of fuel injectors configured to inject a quantity of fuel into a first portion of the internal combustion engine; a second fuel rail configured to connect to the fuel source; a second fuel delivery system comprising a second plurality of fuel injectors connected to the second fuel rail, the second plurality of fuel injectors configured to inject a quantity of fuel into a second portion of the internal combustion engine different from the first portion; as well as a controller operatively connected to the first and second fuel delivery systems, the controller configured to selectively enable and disable operation of the first and second fuel delivery systems based on one of a sensed temperature and a sensed pressure of fuel delivered to corresponding fuel injectors of the first and second pluralities of fuel injectors. 2 . The fuel system of claim 1 , further comprising a first pressure sensor and a first temperature sensor installed in the first fuel rail, and a second temperature sensor and a second pressure sensor installed in the second fuel rail.

3. The fuel system according to claim 2, wherein: The first plurality of fuel injectors are configured to inject fuel upstream of an intake valve of the internal combustion engine.

4. The fuel system according to claim 3, wherein: The second plurality of fuel injectors is configured to inject an amount of fuel directly into a cylinder of the internal combustion engine downstream of the intake valve.

5. The fuel system according to claim 4, wherein: The controller is configured to disable the second fuel delivery system during selected operating periods of the internal combustion engine.

6. The fuel system according to claim 5, wherein: The controller is configured to activate both the first fuel delivery system and the second fuel delivery system if one of a detected temperature in the first fuel rail and a detected pressure in the second fuel rail exceeds a selected value.

7. A method of operating a plurality of fuel injection systems for an internal combustion engine supported in a vehicle, the method comprising: injecting fuel into a first portion of the internal combustion engine via a first plurality of fuel injectors; injecting fuel into a second portion of the internal combustion engine different from the first portion via a second plurality of fuel injectors; detecting an operating mode of the vehicle; disabling the first plurality of fuel injectors based on the operating mode of the vehicle; detecting one of a temperature and a pressure of fuel at the first plurality of fuel injectors; as well as The first plurality of fuel injectors are activated if the one of the temperature and the pressure of the fuel exceeds a selected threshold.

8. The method according to claim 7, wherein: Activating the first plurality of fuel injectors includes detecting a fuel temperature at each of the first plurality of fuel injectors exceeding a selected temperature threshold.

9. The method according to claim 7, wherein: Activating the first plurality of fuel injectors includes detecting a fuel pressure at each of the first plurality of fuel injectors exceeding a selected pressure threshold.

10. The method according to claim 9, wherein: Activating the first plurality of fuel injectors when fuel pressure at the first plurality of fuel injectors exceeds a selected pressure threshold includes delivering fuel to the internal combustion engine without activating a fuel pump.

Images