Description:FIELD OF THE DISCLOSURE
[0001] This invention generally relates to a field of automotive engine control system, and in particular, relates to a smart air control system and a method for reducing oil ingress into the piston during Deceleration Fuel Cut-Off (DFCO) activation to enhance engine performance and reduce emissions.
BACKGROUND
[0002] The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
[0003] In internal combustion engines, maintaining optimal airflow during various operating conditions is crucial for efficient performance and emission control. One common strategy used in modern engines to improve fuel efficiency is Deceleration Fuel Cut-Off (DFCO), where the fuel supply is temporarily halted when the driver releases the accelerator pedal during deceleration. While the DFCO effectively reduces fuel consumption, it can create a significant drop in manifold absolute pressure (MAP), resulting in a strong vacuum effect inside the intake manifold. This increased negative pressure can unintentionally draw engine oil into the piston chamber. Oil ingress not only contributes to oil consumption but also causes incomplete combustion, leading to increased emissions, carbon deposits, and potential damage to critical engine components such as the spark plug and piston.
[0004] Conventional methods struggle to effectively control airflow during the DFCO activation, often failing to maintain stable manifold pressure. This limitation increases the risk of oil being pulled into the piston, impacting engine performance, increasing maintenance needs, and making it challenging to meet stringent emission standards.
[0005] According to a patent application “US10036290B2” titled as “Crankcase ventilation valve for an engine” disclosed as the invention relates to a positive crankcase ventilation valve for an engine is provided with a valve body defining apertures fluidly coupling a crankcase and an intake manifold of the engine, with each aperture sized to prevent an entrained oil droplet from flowing there through. The valve has a valve element supported by the body to selectively cover at least one of the apertures in response to a pressure difference between the manifold and the crankcase to provide variable air flow from the crankcase to the intake manifold. A method includes, in response to an increasing absolute pressure difference between the manifold and the crankcase, passively moving a valve element to selectively cover apertures fluidly coupling the crankcase and the manifold to control an air flow from the crankcase to the intake manifold to a predetermined variable flow profile, and separating oil droplets from the air flow via the apertures.
[0006] According to another patent application “KR19980046420A” titled as “Engine oil consumption reduction method and device” disclosed as the invention provides a method for reducing engine oil consumption, which prevents the formation of high negative pressure in an intake manifold, thereby reducing the suction power of blow-by gas and preventing engine oil consumption, and a device therefor. To achieve the above-mentioned purpose, the method for reducing engine oil consumption of the present invention comprises the steps of: measuring negative pressure in an intake manifold when a fuel cut phenomenon occurs during high-speed operation of an engine; introducing outside air into the intake manifold through an idle speed controller to reduce the negative pressure when the negative pressure measured in the step is higher than a reference value; and blocking the introduction of outside air through the idle speed controller when the negative pressure in the intake manifold reaches a reference value. The invention relates to an engine having a PCV device for refluxing blow-by gas inside a crankcase by the negative pressure of the intake manifold side when the engine is running, the engine comprising: a negative pressure sensor for detecting negative pressure inside the intake manifold when a fuel cut phenomenon occurs during high-speed driving of the engine; an idle speed controller for directly supplying air to the intake manifold side by bypassing the throttle valve from the intake duct when the negative pressure detected by the negative pressure sensor is higher than a reference value; and an electronic control device for controlling the idle speed controller by information detected by the negative pressure sensor.
[0007] However, the disclosed inventions do not disclose about the DFCO activation and oil reduction inside the engine explicitly. Therefore, there is a need for an improved air control strategy that precisely regulates airflow during DFCO activation to reduce negative pressure, minimize oil ingress, and enhance overall engine efficiency and longevity.
 
OBJECTIVES OF THE INVENTION
[0008] The objective of present invention is to provide a smart air control system that effectively regulates airflow during Deceleration Fuel Cut-Off (DFCO) activation to minimize the risk of oil being drawn into the piston.
[0009] Further, the objective of the present invention is to enhance manifold absolute pressure within the intake manifold during DFCO activation, thereby reducing the strong vacuum effect that typically leads to oil ingress.
[0010] Furthermore, the objective of the present invention is to achieve a reduction in engine-out emissions by preventing oil combustion in the piston chamber, resulting in lower particulate matter and hydrocarbon emissions.
[0011] Furthermore, the objective of the present invention is to improve the lifespan of key engine components such as the spark plug and piston by minimizing oil-induced combustion issues.
[0012] Furthermore, the objective of the present invention is to contribute to reduced oil consumption, improving overall engine efficiency and lowering maintenance costs.
[0013] Furthermore, the objective of the present invention is to enhance product quality by ensuring stable engine performance and improved durability in various operating conditions.

 
SUMMARY
[0015] According to an aspect, the present embodiments discloses an air control system for an engine of a vehicle. The air control system comprises one or more sensors configured to detect one or more parameters of the vehicle. The air control system further comprises at least one control unit communicatively coupled to the one or more sensors. The at least one control unit is configured to detect deceleration fuel cut-off (DFCO) activation based at least on the detected one or more parameters. The at least one control unit is further configured to calculate a minimum relative air mass demand during the DFCO activation. The at least one control unit is further configured to determine a maximum allowable air mass. The at least one control unit is further configured to activate a fuel cut unit to stop fuel injection and further limit airflow during deceleration of the vehicle. The at least one control unit is further configured to generate one or more control signals based at least on the calculated minimum relative air mass demand and the determined maximum allowable air mass. The air control system further comprises an airflow regulation unit communicatively coupled to the at least one control unit. The airflow regulation unit is configured to adjust a position of an airflow modulator based at least on the generated one or more control signals.
[0016] In some embodiments, the airflow regulation unit is further configured to regulate airflow within an intake manifold during the DFCO activation to maintain controlled manifold absolute pressure. The airflow regulation unit is further configured to prevent excessive negative pressure build-up in the intake manifold.
[0017] In some embodiments, the one or more parameters comprises at least one of position of a pedal, speed of the engine, torque, coolant temperature, and air mass flow.
[0018] In some embodiments, the minimum relative air mass demand is calculated to determine one or more stable airflow conditions during the DFCO activation.
[0019] In some embodiments, the maximum allowable air mass is determined to ensure the airflow remains within a safe range during the DFCO activation.
[0020] In some embodiments, the airflow modulator comprises at least one of a throttle valve, an electronic actuator, or a variable air bypass valve.
[0021] In some embodiments, the at least one control unit is further configured to adjust the airflow modulator incrementally to achieve a smooth transition during the DFCO activation and DFCO deactivation.
[0022] In some embodiments, the at least one control unit is further configured to activate the airflow regulation unit based on a predefined threshold of negative pressure in the intake manifold.
[0023] According to an aspect, the present embodiments, discloses a method. The method comprises the steps of detecting, via one or more sensors, one or more parameters of the vehicle. Further, the method comprises steps of detecting, via at least one control unit, deceleration fuel cut-off (DFCO) activation based at least on the detected one or more parameters. Further, the method comprises steps of calculating, via the at least one control unit, minimum relative air mass demand during the DFCO activation. Further, the method comprises steps of determining, via the at least one control unit, a maximum allowable air mass. Further, the method comprises steps of activating, via the at least one control unit, a fuel cut unit to stop fuel injection and further limit airflow during deceleration of the vehicle. Further, the method comprises steps of generating, via the at least one control unit, one or more control signals based at least on the calculated minimum relative air mass demand and the determined maximum allowable air mass. Thereafter, the method comprises steps of adjusting, via an airflow regulation unit, a position of an airflow modulator based at least on the generated one or more control signals.
 
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings illustrate various embodiments of systems, methods, and embodiments of various other aspects of the disclosure. Any person with ordinary skills in the art will appreciate that the illustrated element boundaries (e.g. boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. It may be that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of one element may be implemented as an external component in another, and vice versa. Furthermore, elements may not be drawn to scale. Non-limiting and non-exhaustive descriptions are described with reference to the following drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating principles.
[0025] FIG. 1 illustrates a block diagram of an air control system in a vehicle, according to an embodiment of the present invention;
[0026] FIG. 2 illustrates a process flow of the air control system, according to an embodiment of the present invention;
[0027] FIG. 3 illustrates one or more graphs showing relationship between pedal position, air demand, and manifold pressure, in accordance to an embodiment of the present invention; and
[0028] FIG. 4 illustrates a flowchart showing a method for controlling the air control system in the vehicle, according to an embodiment of the present invention.
 
DETAILED DESCRIPTION
[0030] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words “comprising,” “having,” “containing,” and “including,” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
[0031] Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the preferred, systems and methods are now described. Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings in which like numerals represent like elements throughout the several figures, and in which example embodiments are shown. Embodiments of the claims may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The examples set forth herein are non-limiting examples and are merely examples among other possible examples.
[0032] FIG. 1 illustrates a block diagram of an air control system (100) in a vehicle, according to an embodiment of the present invention. FIG. 2 illustrates a process flow of the air control system (100), according to an embodiment of the present invention.
[0033] In some embodiments, an air control system (100) in a vehicle is configured to regulate a flow of air entering to an engine of the vehicle. The regulation of the air is essential because the engine requires a precise balance of the air and fuel to operate efficiently. Too much or too little air can affect performance, fuel efficiency, and even cause damage to one or more components of the engine. In some embodiments, when the vehicle accelerates, the engine needs more air to burn fuel efficiently and generate power. The air control system (100) is configured to ensure that an optimal amount of air enters at the right time.
[0034] In some embodiments, the air control system (100) is configured to stabilize the engine’s performance during changes in speed or load. In one example, when a user takes his foot off the accelerator while driving downhill or slowing down, the engine’s demand for air decreases sharply. If airflow isn’t properly controlled in this situation, it could create an imbalance, such as excessive vacuum pressure inside the engine’s intake manifold. The imbalance can lead to problems like oil being drawn into the piston area, which may cause oil burning and damage engine parts. By precisely managing airflow, the air control system (100) is configured to prevent such issues. The air control system (100) is further configured to ensure stable engine performance by maintaining optimal air pressure levels inside the engine.
[0035] In some embodiments, the air control system (100) comprises one or more sensors (102), at least one control unit (104) communicatively coupled to the one or more sensors (102), and an airflow regulation unit (106) communicatively coupled to the at least one control unit (104).
[0036] In some embodiments, the one or more sensors (102) is configured to detect one or more parameters of the vehicle. The one or more parameters comprises at least one of position of a pedal, speed of the engine, torque, coolant temperature, and air mass flow. The one or more sensors (102) is configured to detect the position of the pedal corresponding to an acceleration input or a deceleration input. The pedal corresponds to an accelerator pedal. In one example, when the pedal is released, the at least one control unit (104) identifies a deceleration phase.
[0037] In some embodiments, the at least one control unit (104) is configured to detect deceleration fuel cut-off (DFCO) activation based at least on the detected one or more parameters. When the vehicle enters the deceleration phase, the at least one control unit (104) identifies the deceleration phase and triggers DFCO. In one example, the deceleration phase occurs when a user lifts his foot off the accelerator. The user corresponds to a driver. The DFCO corresponds to a fuel-saving feature that temporarily stops fuel injection during deceleration.
[0038] In some embodiments, the at least one control unit (104) is configured to calculate a minimum relative air mass demand during the DFCO activation. The minimum relative air mass demand is calculated to determine one or more stable airflow conditions during the DFCO activation. By calculating the minimum relative air mass demand, the at least one control unit (104) ensures that the engine receives just enough air to prevent unstable combustion conditions, maintain proper pressure balance, and avoid excessive vacuum formation.
[0039] In some embodiments, the at least one control unit (104) is further configured to determine a maximum allowable air mass. The maximum allowable air mass is determined to ensure the airflow remains within a safe range during the DFCO activation. Determining the maximum allowable air mass prevents too much air from entering the engine, which could disrupt combustion dynamics or cause instability.
[0040] In some embodiments, the at least one control unit (104) is further configured to activate a fuel cut unit to stop fuel injection and further limit airflow during deceleration of the vehicle. Stopping of the fuel injection and limiting the airflow prevents excessive negative pressure build-up in the intake manifold.
[0041] In some embodiments, the at least one control unit (104) is further configured to generate one or more control signals based at least on the calculated minimum relative air mass demand and the determined maximum allowable air mass. The generated one or more control signals are sent to the airflow regulation unit (106) to adjust the airflow precisely during the DFCO activation. By dynamically adjusting the air supply in response to changing engine conditions, the at least one control unit (104) maintains stable combustion and prevents engine misfires.
[0042] In some embodiments, the at least one control unit (104) is further configured to adjust the airflow modulator incrementally to achieve a smooth transition during the DFCO activation and DFCO deactivation. The at least one control unit (104) is further configured to adjust the airflow modulator in incremental steps rather than sudden changes. The gradual adjustment ensures a smooth transition during both the DFCO activation and the DFCO deactivation. The DFCO activation occurs when fuel is cut off. Further, the DFCO deactivation occurs when the fuel injection resumes. In some embodiments, smooth airflow transitions prevent engine hesitation, stalling, or rough idling. In one example, instead of rapidly closing the airflow path, the at least one control unit (104) progressively reduces the airflow to maintain steady engine performance.
[0043] In some embodiments, the at least one control unit (104) is further configured to activate the airflow regulation unit (106) based on a predefined threshold of negative pressure in the intake manifold. Excessive negative pressure can create a strong suction effect that risks pulling engine oil into a combustion chamber. The negative pressure corresponds to vacuum build-up. By activating the airflow regulation unit (106) at the predefined threshold, the at least one control unit (104) prevents negative pressure from reaching dangerous levels, ensuring stable engine conditions.
[0044] In some embodiments, the airflow regulation unit (106) is configured to adjust a position of an airflow modulator based at least on the generated one or more control signals. The airflow modulator comprises at least one of a throttle valve, an electronic actuator, or a variable air bypass valve. The throttle valve corresponds to a movable valve that controls the volume of air entering the engine’s intake manifold. The electronic actuator corresponds to a motorized device that precisely adjusts the throttle valve or other airflow devices based on electronic signals. Further, the variable air bypass valve corresponds to a dedicated valve designed to regulate airflow independently of the throttle.
[0045] In some embodiments, the airflow regulation unit (106) is further configured to regulate airflow within an intake manifold during the DFCO activation to maintain controlled manifold absolute pressure. In some embodiments, the airflow regulation unit (106) is further configured to prevent excessive negative pressure build-up in the intake manifold.
[0046] FIG. 3 illustrates one or more graphs showing relationship between pedal position, air demand, and manifold pressure, in accordance to an embodiment of the present invention.
[0047] In some embodiments, the graph 300 illustrates the pedal position as a percentage. The pedal position represents the user’s throttle input. At the start of the graph 300, the pedal position is shown at 100%, indicating that the user has fully pressed the accelerator. When the pedal position is shown at 100%, the engine is delivering maximum power, with high airflow and fuel injection. As the graph 300 progresses, the pedal position drops suddenly to 0%, representing the user has completely released the accelerator. The dropping of the pedal position triggers the DFCO condition, where the engine switches to a deceleration phase. The drop in the pedal position is a crucial trigger for activating the airflow control and the fuel cut-off mechanism.
[0048] In some embodiments, the graph 302 illustrates the minimum relative air demand, represented as a ratio. At the start of the graph 302, the relative air demand is shown at approximately 1.3. The value of the relative air demand corresponds to the air demand when the pedal is pressed, ensuring sufficient airflow for combustion. As the pedal position drops to 0%, the relative air demand decreases rapidly, reflecting the reduction in airflow requirements during deceleration. The air demand continues to decline but stabilizes above zero. Maintaining the controlled air demand is crucial to preventing excessive vacuum build-up in the intake manifold.
[0049] In some embodiments, the graph 304 illustrates the manifold absolute pressure (MAP) in kilopascal (kPa). The MAP corresponds to a critical indicator of the pressure conditions inside the intake manifold. Initially, the MAP is close to 200 kPa, which corresponds to normal engine load conditions when the pedal is pressed, and the engine is actively drawing in air. As the pedal position drops to zero, the MAP rapidly decreases to approximately 35 kPa. The pressure drop is due to the sudden reduction in airflow when the fuel cut-off activates and the throttle closes. The graph 304 shows a blue band representing a stable pressure zone maintained by the airflow control system (100). The stability is crucial because excessive negative pressure could create strong suction, pulling engine oil past the piston rings into the combustion chamber.
[0050] FIG. 4 illustrates a flowchart (400) showing a method for controlling the air control system (100) in the vehicle, according to an embodiment of the present invention.
[0051] At operation 402, the one or more sensors (102) are configured to detect the one or more parameters of the vehicle. The one or more parameters comprises at least one of position of the pedal, the speed of the engine, the torque, the coolant temperature, and the air mass flow. The one or more sensors (102) are configured to detect the position of the pedal corresponding to the acceleration input or the deceleration input. The pedal corresponds to the accelerator pedal.
[0052] At operation 404, the at least one control unit (104) is configured to detect the DFCO activation based at least on the detected one or more parameters. When the vehicle enters the deceleration phase, the at least one control unit (104) identifies the deceleration phase and triggers the DFCO. In one example, the deceleration phase occurs when the user lifts his foot off the accelerator.
[0053] At operation 406, the at least one control unit (104) is configured to calculate the minimum relative air mass demand during the DFCO activation. The minimum relative air mass demand is calculated to determine the one or more stable airflow conditions during the DFCO activation. By calculating the minimum relative air mass demand, the at least one control unit (104) ensures that the engine receives just enough air to prevent the unstable combustion conditions, maintain proper pressure balance, and avoids the excessive vacuum formation.
[0054] At operation 408, the at least one control unit (104) is configured to determine the maximum allowable air mass. The maximum allowable air mass is determined to ensure the airflow remains within the safe range during the DFCO activation. Determining the maximum allowable air mass prevents too much air from entering the engine, which could disrupt the combustion dynamics or cause the instability.
[0055] At operation 410, the at least one control unit (104) is configured to activate the fuel cut unit to stop fuel injection and further limit airflow during deceleration of the vehicle. Stopping of the fuel injection and limiting the airflow prevents excessive negative pressure build-up in the intake manifold.
[0056] At operation 412, the at least one control unit (104) is further configured to generate the one or more control signals based at least on the calculated minimum relative air mass demand and the determined maximum allowable air mass. The generated one or more control signals are sent to the airflow regulation unit (106) to adjust the airflow precisely during the DFCO activation. By dynamically adjusting the air supply in response to changing engine conditions, the at least one control unit (104) maintains the stable combustion and prevents the engine misfires.
[0057] At operation 414, the at least one control unit (104) is further configured to adjust the airflow modulator incrementally to achieve the smooth transition during the DFCO activation and DFCO deactivation. The at least one control unit (104) is further configured to adjust the airflow modulator in incremental steps rather than sudden changes. The gradual adjustment ensures the smooth transition during both the DFCO activation and the DFCO deactivation. The DFCO activation occurs when the fuel is cut off. Further, the DFCO deactivation occurs when the fuel injection resumes. In some embodiments, the smooth airflow transitions prevent the engine hesitation, the stalling, or the rough idling. In one example, instead of rapidly closing the airflow path, the at least one control unit (104) progressively reduces the airflow to maintain steady engine performance.
[0058] It should be noted that the air control system (100) in the vehicle in any case could undergo numerous modifications and variants, all of which are covered by the same innovative concept; moreover, all of the details can be replaced by technically equivalent elements. In practice, the components used, as well as the numbers, shapes, and sizes of the components can be of any kind according to the technical requirements. The scope of protection of the invention is therefore defined by the attached claims
, Claims:WE CLAIM:
1. An air control system (100) for an engine of a vehicle comprising:
one or more sensors (102) configured to detect one or more parameters of the vehicle;
at least one control unit (104) communicatively coupled to the one or more sensors (102), wherein the at least one control unit (104) is configured to:
detect deceleration fuel cut-off (DFCO) activation based at least on the detected one or more parameters;
calculate a minimum relative air mass demand during the DFCO activation;
determine a maximum allowable air mass;
activate a fuel cut unit to stop fuel injection and further limit airflow during deceleration of the vehicle; and
generate one or more control signals based at least on the calculated minimum relative air mass demand and the determined maximum allowable air mass; and
an airflow regulation unit (106) communicatively coupled to the at least one control unit (104), wherein the airflow regulation unit (106) is configured to adjust a position of an airflow modulator based at least on the generated one or more control signals.

2. The air control system (100) as claimed in claim 1, wherein the airflow regulation unit (106) is further configured to:
regulate airflow within an intake manifold during the DFCO activation to maintain controlled manifold absolute pressure; and
prevent excessive negative pressure build-up in the intake manifold.

3. The air control system (100) as claimed in claim 1, wherein the one or more parameters comprises at least one of position of a pedal, speed of the engine, torque, coolant temperature, and air mass flow.

4. The air control system (100) as claimed in claim 1, wherein the minimum relative air mass demand is calculated to determine one or more stable airflow conditions during the DFCO activation.

5. The air control system (100) as claimed in claim 1, wherein the maximum allowable air mass is determined to ensure the airflow remains within a safe range during the DFCO activation.

6. The air control system (100) as claimed in claim 1, wherein the airflow modulator comprises at least one of a throttle valve, an electronic actuator, or a variable air bypass valve.

7. The air control system (100) as claimed in claim 1, wherein the at least one control unit (104) is further configured to adjust the airflow modulator incrementally to achieve a smooth transition during the DFCO activation and DFCO deactivation.

8. The air control system (100) as claimed in claim 1, wherein the at least one control unit (104) is further configured to activate the airflow regulation unit (106) based on a predefined threshold of negative pressure in the intake manifold.

9. A method comprising:
detecting, via one or more sensors (102), one or more parameters of the vehicle;
detecting, via at least one control unit (104), deceleration fuel cut-off (DFCO) activation based at least on the detected one or more parameters;
calculating, via the at least one control unit (104), minimum relative air mass demand during the DFCO activation;
determining, via the at least one control unit (104), a maximum allowable air mass;
activating, via the at least one control unit (104), a fuel cut unit to stop fuel injection and further limit airflow during deceleration of the vehicle;
generating, via the at least one control unit (104), one or more control signals based at least on the calculated minimum relative air mass demand and the determined maximum allowable air mass; and
adjusting, via an airflow regulation unit (106), a position of an airflow modulator based at least on the generated one or more control signals.

10. The method as claimed in claim 9, wherein the one or more parameters comprises at least one of position of a pedal, speed of the engine, torque, coolant temperature, and air mass flow.