Methods and systems of controlling an idle air control valve (IACV) for an engine

Abstract

Embodiments provide methods (300, 400) and systems (200) of controlling an idle air control valve (IACV) (214) for an engine (112). The method (300, 400) involves a controller (202) accessing (302, 402) a start air temperature indicative of an atmospheric air temperature when the engine (112) starts, accessing (304, 404) an air mass flow rate entering the engine (112), determining (306, 410) a modelled engine oil temperature at least based on the start air temperature, and the air mass flow rate, and subsequently controlling (308, 420) an opening of the idle air control valve (IACV) (214) based on the modelled engine oil temperature, all under the control of the controller (202).

Description

METHODS AND SYSTEMS OF CONTROLLING AN IDLE AIR CONTROL VALVE (IACV) FORAN ENGINECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Indian Non-provisional patent application 202411025953, filed on 29thMarch 2024 which is incorporated herein in its entirety by this reference thereto.FIELD OF INVENTION

[0002] The present invention relates to internal combustion engines and more particularly relates to the control mechanism of an idle air control valve for the internal combustion engines.BACKGROUND

[0003] An Idle Air Control Valve, often abbreviated as IACV or IAC, is an electromechanical device located within the engine’s air intake system. The IACV is a crucial part of the engine’s air intake system. Its primary function is to regulate the engine’s idle speed by controlling the amount of air that enters the engine. Unlike traditional carburetted engines where idle speed was adjusted manually, modem engines equipped with fuel injection systems rely on the IACV for idle speed control.

[0004] During normal engine operation, the throttle plate regulates the flow of air into the engine based on driver inputs. However, during idle conditions such as starting, deceleration, or when the load on the engine changes, a stable idle speed is maintained by the IACV.

[0005] To maintain the desired idle engine RPM under various operating conditions, the Idle Air Control Valve (IACV) plays a critical role. The IACV operates by precisely regulating the amount of air that bypasses the closed throttle plate. This control allows the engine management system to precisely control idle speed. By opening or closing the IACV in response to Engine Management System (EMS) signals, it is ensured that the engine receives the correct air amount for a consistent idle speed across various operating conditions.

[0006] Conventional systems rely on an engine oil temperature (EOT) sensor located at the engine head to control the Idle Air Control Valve (IACV). This sensor measures engine oil temperature, which is then used to regulate the IACV However, the EOT sensorreading reflects oil temperature at the head, which may not directly correlate with the oil temperature in the sump. For instance, the sump temperature often exhibits sluggish behavior during engine startup or in cold conditions, whereas the EOT sensor reading shows the linear characteristics with time. Consequently, the EOT sensor value does not accurately reflect the temperature of the oil within the engine's sump.

[0007] Consequently, there is a pressing need to address the aforementioned limitations through the development of innovative control strategies for controlling the operation of the IACV.SUMMARY

[0008] The present invention discloses an innovative control mechanism for an idle air control valve (IACV), designed for vehicles and other applications utilizing combustion engines. This mechanism precisely regulates the position of the IACV across varying ambient temperatures, optimizing its operation during idle conditions, including startup, deceleration, or changes in engine load. This ensures optimal airflow for consistent engine speed regardless of ambient temperatures. Thus, this inventive solution directly addresses the limitations of being solely reliant on engine oil temperature sensor, ensuring optimum control of the IACV while considering ambient conditions.

[0009] Moreover, the present invention focuses on the accurate determination of the sump oil temperature. This eliminates the need for additional temperature sensors by potentially leveraging a model of the engine oil’s thermal behavior. Thus, by accounting for the engine oil’s overall thermal state, the control strategies can be enhanced in terms of accuracy and precision.

[0010] To achieve the above and other objectives, in an aspect of the present invention, there is provided a method of controlling an idle air control valve (IACV) for an engine. The method comprises accessing, by a controller, a start air temperature indicative of an atmospheric air temperature when the engine starts. The method comprises accessing, by the controller, an air mass flow rate entering the engine. The method further comprises determining, by the controller, a modelled engine oil temperature at least based on the start air temperature, and the air mass flow rate. The modelled engine oil temperature is indicative of temperature of engine oil within a sump of the engine. Upon determination of the modelled engine oil temperature, the method includes controlling, by the controller, an opening of the idle air control valve (IACV) based on the modelled engine oil temperature.

[0011] In one aspect, accessing the air mass flow rate comprises accessing the air mass flow rate entering the engine at a time instance (ti). The determining the modelled engineoil temperature comprises calculating the modelled engine oil temperature for a time instance (t2) based on the air mass flow rate entering the engine at the time instance (ti), the start air temperature, and the modelled temperature at the time instance (ti). The time instance (t2) is higher than the time instance (ti).

[0012] In one aspect, controlling the opening of the idle air control valve (IACV) comprises accessing, by the controller, an engine oil temperature from an engine oil temperature (EOT) sensor at the time instance (t2). The engine oil temperature is indicative of temperature of engine oil at head of the engine. The controlling further comprises determining, by the controller, a position value of the IACV (IACVEOT) corresponding to the accessed engine oil temperature at the time instance (t2). The controlling further comprises determining, by the controller, an offset value (IACVOFFSET) corresponding to the modelled engine oil temperature for the time instance (t2). The controlling further comprises determining, by the controller, a corrective position value for the IACV (IACVCORRECTIVE) for the time instance (t2) based on the position value (IACVEOT) and the offset value (IACVOFFSET). The controlling further comprises controlling, by the controller, the opening of the idle air control valve (IACV) at time instance (t2) by adjusting a position of the IACV according to the determined corrective position value (IACV CORRECTIVE) .

[0013] In one aspect, the modelled engine oil temperature for time instance (t2) is calculated based on a coefficient factor stored in a pre-stored look-up table. The coefficient factor corresponds to the air mass flow rate entering the engine at time instance (ti) and the start air temperature.

[0014] In one aspect, accessing a start air temperature comprises receiving a signal from one of: an ambient sensor coupled to the controller; or a Temperature Manifold Absolute Pressure (TMAP) sensor located at intake manifold on the engine.

[0015] In one aspect, accessing the air mass flow rate entering into the engine comprises receiving a signal from a Temperature Manifold Absolute Pressure (TMAP) sensor located at intake manifold on the engine.

[0016] In one aspect, the corrective position value of the IACV (IACVCORRECTIVE) is determined as:IACVCORRECTIVE = IACVOFFSET + IACVEOT.

[0017] In one aspect, the method comprises checking whether the engine oil temperature is less than a predefined threshold. The modelled engine oil temperature is determined when the engine oil temperature is less than a predefined threshold.

[0018] In one aspect, the offset value corresponds to a deviation between the engineoil temperature and the modelled engine oil temperature.

[0019] According to another aspect of the present invention, there is provided a vehicle that comprises an engine and an idle air control valve (IACV) configured to control an amount of air entering into the engine. The vehicle further comprises a controller configured to execute machine-readable instructions to perform, at least in part, to access a start air temperature indicative of an atmospheric air temperature when the engine starts. The controller is further configured to access an air mass flow rate entering the engine and determine a modelled engine oil temperature based at least on the start air temperature, and the air mass flow rate. The modelled engine oil temperature is indicative of temperature of engine oil within a sump of the engine. The controller is configured to control an opening of the idle air control valve (IACV) based on the modelled engine oil temperature.BRIEF DESCRIPTION OF THE FIGURES

[0020] The invention itself, together with further features and advantages, will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example only wherein like reference numerals represent like elements and in which:

[0021] Figure 1 illustrates a side view of a vehicle, in accordance with an exemplary embodiment of the present invention;

[0022] Figure 2A illustrates a system for controlling an idle air control valve (IACV) for an engine, in accordance with an embodiment of the present invention;

[0023] Figure 2B illustrates a graphical representation of the engine oil temperature accessed through engine oil temperature (EOT) sensor and the modelled engine oil temperature over time, in accordance with an embodiment of the present disclosure;

[0024] Figure 3 illustrates a method for controlling an idle air control valve (IACV) for an engine, in accordance with an embodiment of the present invention;

[0025] Figure 4 illustrates a method for controlling an idle air control valve (IACV) for an engine, in accordance with another embodiment of the present invention; and

[0026] FIG. 5 illustrates a graphical representation showing variation of the position values of IACV for different ambient temperatures, according to an embodiment of the present invention.

[0027] The drawings referred to in this description are not to be understood as beingdrawn to scale except if specifically noted, and such drawings are only exemplary in nature.DETAILED DESCRIPTION

[0028] While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and the scope of the invention.

[0029] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device, or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus preceded by “comprises. . . a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.

[0030] For the better understanding of this invention, reference would now be made to the embodiment illustrated in the accompanying figures and description here below. Further, in the following figures, the same reference numerals are used to identify the same components in various views.

[0031] While the present invention is illustrated in the context of a two-wheeled or saddle-riding type vehicle, however, method and system described herein for controlling fuel reactivation for an engine, can be used with other types of vehicles (e.g., three, four, or more wheelers) as well as with any combustion engines used in non-vehicular applications. It is to be noted that terms such as “scooter-type vehicle”, “two-wheeled vehicle” and “vehicle” are interchangeably used throughout the description. The term “two-wheeled vehicle” includes vehicles such as motorcycles, scooters, bicycles, mopeds, all-terrain vehicles (ATVs), and the like.

[0032] The terms “front / forward”, “rear / rearward / back / backward”, “up / upper / top / upward”, “down / lower / lowerward / downward”, “left / leftward”, “right / rightward” used therein represents the directions as seen from a vehicle driver sitting astride and these directions are referred by arrows Fr, Rr, U, Lr, L, R in the drawing figures.

[0033] Figure 1 illustrates a side view of a vehicle (100), in accordance with anexemplary embodiment of the present invention. The vehicle (100) referred to herein, embodies a two-wheeled vehicle. Alternatively, the vehicle (100) may embody any other ridden vehicles such as scooters, three-wheeled vehicles, all-terrain vehicles (ATVs), etc., without limiting the scope of the invention.

[0034] The vehicle (100) includes a body frame (102), a steering assembly (104), and at least one front ground engaging member (106). The body frame (102) supports the steering assembly (104), and the at least one front ground engaging member (106) in a front portion (107) of the vehicle (100). The steering assembly (104) is pivotally mounted on the body frame (102). The at least one front ground engaging member (106) is operatively coupled to the steering assembly (104). The steering assembly (104) includes a handlebar (108). The handlebar (108) is configured to be rotated by a rider to steer the vehicle (100). Further, the front portion (107) of the vehicle (100) may include front fenders, dash assembly, mirrors, indicator lights, etc. without limiting the scope of the invention.

[0035] Further, the vehicle (100) includes a power unit (110) and at least one rear ground engaging member (111). In the illustrated example, the power unit (110) provides the necessary power required to drive the at least one rear ground engaging member (111) of the vehicle (100). Alternatively, the power unit (110) may provide the necessary power to drive the at least one front ground engaging member (106), or both the at least one front ground engaging member (106) and the at least one rear ground engaging member (111) simultaneously, without limiting the scope of the disclosure. The body frame (102) supports the power unit (110) in a middle portion (109) of the vehicle (100). The power unit (110) includes an engine (112) and a transmission unit (not shown). The engine (112) generates the power required by the vehicle (100). The transmission unit transmits the generated power to the at least one front ground engaging member (106) and / or the at least rear ground engaging member (111). Further, an exhaust pipe (120) is fluidically coupled with an exhaust port (not shown in Figure 7) of the engine (112). The exhaust pipe (120) has been provided with a muffler (122) at an end of the exhaust pipe (120) towards a rear portion (113) of the vehicle (100). The muffler (122) is configured to reduce the noise created by pressurized exhaust air leaving the engine (112) by allowing the pressurized exhaust air to expand within an expansion chamber of the muffler (122).

[0036] The vehicle (100) further includes a fuel tank (114), and a seat member (116). The fuel tank (114) is configured to store the fuel required by the engine (112) to power the vehicle (100). The fuel tank (114) extends from the front portion (107) to the middle portion (109) of the vehicle (100). Further, the body frame (102) supports the seat member (116) whichextends from the middle portion (109) to the rear portion (113) of the vehicle (100). The rear ground engaging member (111) is supported by the body frame (102) at the rear portion (113) of the vehicle (100). The fuel tank (114) provides the necessary fuel to the engine (112) to generate power within the vehicle (100). The seat member (116) provides seating for the rider and a passenger of the vehicle (100). Further, the seat member (116) includes a rider’s seat (118), and a pillion seat (119). The rider’s seat (118) provides seating for the rider, and the pillion seat (119) provides seating for the passenger of the vehicle (100).

[0037] It may be noted that the vehicle (100) is shown to have included the abovestated parts, however, those skilled in the art would appreciate that the vehicle (100) includes other parts which may not be relevant for explaining the present invention and hence are not shown and described.

[0038] Figure 2A illustrates a system (200) for controlling an idle air control valve (IACV) for an engine (112), in accordance with an embodiment of the present invention. The system (200) includes a controller (202). The controller (202) can take the form of either a microprocessor or similar programmable devices. As an example, the controller (202) may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU). a hardware accelerator, a special-purpose computer chip, integrated circuits, or the like.

[0039] In several embodiments of the invention, the controller (202) may be an Electronic Control Unit (ECU) of an Engine Management System (EMS) (205) of the vehicle (100). Further, the controller (202) is operably connected to a memory unit (203). The memory unit (203) may be a volatile storage memory, such as Static Random Access Memory (SRAM) and Dynamic Random Access Memory (DRAM) of types such as Asynchronous DRAM, Synchronous DRAM, Double Data Rate SDRAM, Rambus DRAM, and Cache DRAM, etc., or a non-volatile storage memory such as EPROM, EEPROM or flash memory or the like.

[0040] The system (200) may include an engine oil temperature (EOT) sensor (220) configured with the engine (112) to measure the temperature of engine oil. In an embodiment, the EOT sensor (220) may be configured at the head of the engine body to measure the engine oil temperature present at the head of the engine body. The EOT sensor (220) can be a thermal sensor. The EOT sensor (220) can take the form of a variety of configurations. For example, a temperature-sensitive element, such as a thermistor or a resistance temperature detector (RTD).As the temperature of the engine oil changes, the resistance of the temperature-sensitive element also changes. This change in resistance is then converted into an electrical signal.

[0041] In another example, the EOT sensor (220) may be one of a contact thermal sensor (e.g., a thermocouple, a resistance temperature detector (RTD), a thermistor, etc.) or a non-contact thermal sensor (e.g., an optical pyrometer, a radiation thermometer, a thermal imager, etc.) configured to measure temperature of the engine oil. The EOT sensor (220) is electronically connected to the controller (202) of the Engine Management System (EMS) (205). The controller (202) may receive an electrical signal from the EOT sensor (220) corresponding to at least one of the temperature of the engine oil at the head of the engine body or the temperature of the engine oil at the middle section of the engine (112).

[0042] The system (200) may include a throttle valve (212) configured between an intake manifold (222) and an intake port (208) of the engine (112). The throttle valve (212) may regulate the flow of air into the engine (112) based on inputs provided by the driver. In other words, the position of the throttle valve (212) can be controlled by the driver through an accelerator. For example, through operating the accelerator, the throttle valve (212) can be opened to allow more air to enter the engine (112) and thus increasing the power output. Similarly, the accelerator also allows the throttle valve (212) to close, causing reduction in airflow and decreasing in power output. The airflow from the throttle valve (212) travels into the combustion chamber (216), where it combines with fuel for combustion.

[0043] From the combustion chamber (216), the air moves or flows toward the exhaust port (210). This typically occurs after the air has been utilized in the combustion process within the chamber. The exhaust port (210) serves as an exit point for the combustion gases and remaining air mixture to leave the combustion chamber (216) and enter the exhaust system of the engine (112).

[0044] The system (200) includes an idle air control valve (IACV) (214) positioned in parallel to the throttle valve (212). Thus, the IACV (214) provides an alternate path for airflow between the intake manifold (222) and the engine (112). The IACV (214) may be configured to regulate the idle speed of the engine (112) by controlling the amount of air that bypasses the throttle valve (212). The IACV (214) may use a stepper motor, solenoid or other actuator mechanism to control the position of the valve to allow flow controlled amount of air. The IACV (214) may be operated in steps or increments to adjust the airflow bypassing the throttle valve (212). For instance, in a scenario where there are a total of 300 steps available, the controller (202) may designate a position value as 220. Subsequently, the position of the IACV (214) is modified accordingly, facilitating the regulation of airflow to the combustionchamber (216) of the engine (112).

[0045] The system (200) further includes at least one Temperature Manifold Absolute Pressure (TMAP) sensor (218) associated with the engine (112). The TMAP sensor (218) may be coupled with at least a part of the throttle valve (212) or intake manifold (222) of the vehicle. The TMAP sensor (218) may measure at least the absolute pressure and temperature of the air entering the intake manifold (222). The values corresponding to absolute pressure of the air may be converted to determine an air mass flow rate. Thus, the determined air mass flow rate corresponds to airflow through the intake manifold (222) i.e. air flowing through both the throttle valve (212) and the IACV (214). In other words, the determined air mass flow rate indicates all the air entering the engine (112).

[0046] The TMAP sensor (218) may also be configured to measure a start air temperature, where the start air temperature may be indicative of a starting temperature of ambient air. When the engine (112) starts, the temperature measured by the TMAP sensor (218) corresponds to ambient air temperature, thus indicating the start air temperature.

[0047] There may be various alternative techniques for determining the start air temperature, well-recognized within the field, and those are intentionally omitted here to ensure conciseness. In some embodiments, the system (200) may include an ambient sensor configured with electronic control unit (ECU) or EMS, or below the seat of the vehicle. However, ambient sensor may be installed in any other part of the vehicle such as near the body of the engine (112) and so on, without limiting the scope of the invention.

[0048] Traditionally, the engine oil temperature (EOT) sensor (212) has been used to control the Idle Air Control Valve (IACV). The controller (202) may access an engine oil temperature from the EOT sensor (220). Based on the engine oil temperature from the EOT sensor (220), the controller (202) may determine a corresponding position value of the IACV (IACVEOT) to control the position of the IACV (214).

[0049] However, the EOT sensor (220)’s placement on the engine head prevents it from accurately measuring the oil temperature in the sump of the engine (112). Referring to FIG. 2B, the engine oil temperature measured through EOT sensor (TEOT) varies linearly with time, while the oil temperature within the sump exhibits sluggish behaviour. In other words, the oil temperature changes slowly over time i.e. resisting rapid temperature fluctuations. This leads to a deviation between the engine oil temperature and the sump oil temperature, particularly during start of the engine or cold temperature conditions. Consequently, the EOT sensor reading does not accurately reflect the true value of engine oil temperature. The sump oil temperature, on the other hand, serves as a more reliable indicator of overall engine temperature. Therefore,the sump oil temperature is modelled to accurately determine the engine oil temperature during cold temperature conditions. FIG. 2B depicts how the modelled engine oil temperature (TMODEL) and EOT sensor reading vary with time. Further, the deviation between the model engine oil temperature and EOT sensor reading persists for a predefined time period. After the predefined period, the EOT sensor reading aligns with the sump oil temperature. Therefore, the determined position valve of IACV (IACVEOT) is corrected based on the engine oil temperature within the sump of the engine (112). To determine the corrected position valve, engine oil temperature is modelled to accurately determine the temperature of the engine oil within the sump of the engine (112).

[0050] The system (200) may determine a modelled engine oil temperature indicative of temperature of engine oil within a sump of the engine (112). The sump of an engine (112) (interchangeably referred to as “oil pan” or “oil sump”) is a reservoir located at the bottom of the engine (112). It serves as a storage container for engine oil, which is vital for lubricating various moving parts within the engine (112), such as the pistons, crankshaft, and camshaft. The sump is designed to hold a specific volume of oil, ensuring that an adequate supply is available to lubricate the engine’s components during operation.

[0051] The system (200) may determine the modelled engine oil temperature based on the air mass flow rate accessed through the TMAP sensor (218) and start air temperature accessed through the TMAP sensor (218) or ambient sensor. In an example, the modelled engine oil temperature at any time instance (t2) is calculated as follows:Tmodel (t2)—Tmodel(tl) + Tcoeff(tl) • • • (!)Where the time instance (t2) is higher than the time instance (ti). Tmodel (ti) is modelled engine oil temperature at a time instance (ti) and Tcoeff is temperature coefficient at time instance (ti). The Tcoeff is determined based on the start air temperature and air mass flow rate entering the engine (112) at time instance (ti). An elaborate elucidation concerning the determination of this modelled temperature (Tmodel), founded on temperature coefficient (Tcoeff) utilizing the start air temperature and determined air mass flow rate, is provided with reference to Figure 3.

[0052] Upon determination of the modelled engine oil temperature, the controller (202) is programmed to control the opening of the idle air control valve (IACV) based on the modelled engine oil temperature. In an example, based on the modelled engine oil temperature, the controller (202) is programmed to determine a position value or a step value for IACV (214) to adjust the opening of the IACV (214).

[0053] In an embodiment, the modelled engine oil temperature is utilized to correct the conventional position value for the IACV (214) determined based on the EOT sensor (220).Therefore, the controller (202) is programmed to determine an offset value (IACVOFFSET) corresponding to the modelled engine oil temperature. The offset value corresponds to a deviation between the engine oil temperature (measured through EOT sensor) and the modelled engine oil temperature. In other words, the offset value indicates a correction factor to a corrective position value of the IACV (214), ensuring precise control of the IACV (214). Once the modelled engine oil temperature is calculated for a specific time instance (t2), the offset value (IACVOFFSET) is also determined for that same time instance (t2).

[0054] As described earlier, the controller (202) may determine a position value of the IACV (IACVEOT) corresponding to the accessed engine oil temperature. Based on the position value of the IACV (IACVEOT) and the offset value (IACVOFFSET), a corrective position value for the IACV (IACVCORRECTIVE) is computed. The corrective position value of the IACV (IACVCORRECTIVE) is determined as:IACVCORRECTIVE = IACVOFFSET + IACVEOT . . . (2)Upon determination of the corrective position value (IACVCORRECTIVE), the controller (202) may transmit a signal to IACV (214) to adjust the position of the IACV (214) according to the corrective position value (IACVCORRECTIVE). An elaborate elucidation concerning the determination of the corrective position value (IACVCORRECTIVE), utilizing the position value of the IACV (IACVEOT) and the offset value (IACVOFFSET), is provided with reference to Figure 4.

[0055] Referring now to FIG. 3, a flow diagram of a method 300 for controlling an idle air control valve (IACV) for an engine, is shown, according to an embodiment of the present invention. The method (300) is performed by a controller such as the controller (202).

[0056] At step (302), the method (300) includes the controller (202) accessing a start air temperature indicative of an atmospheric air temperature when the engine (112) starts. As previously discussed, this start air temperature can be acquired through several means. One of these means involves utilizing data from the TMAP sensor (218) present in the system (200). Additionally, or alternatively, the start air temperature can also be obtained from the ambient sensor. By leveraging these sources of information, the method (300) effectively ensures a comprehensive understanding of the ambient temperature, a key factor for subsequent control actions.

[0057] At step (304), the method (300) includes the controller (202) accessing an air mass flow rate entering the engine (112). In particular, the controller (202) utilizes data from the TMAP sensor (218) present in the system (200) to ascertain the air mass flow rate. In certain configurations, the controller (202) can access the air mass flow rate by receiving an input signalfrom a TMAP sensor (218) and determining an air mass flow rate based on the received input signal.

[0058] At step (306), the method (300) includes the controller (202) determining a modelled engine oil temperature indicative of a temperature of engine oil within a sump of the engine (112). The determination of the modelled engine oil temperature is based at least on the start air temperature, and the air mass flow rate. The start air temperature and air mass flow rate are pivotal factors in determining the modelled engine oil temperature for the subsequent controlling of the IACV (214). This dynamic correlation of the start air temperature and the air mass flow rate with engine oil temperature highlights the intricate control strategy employed by the controller (202) to ensure the efficient and optimum control of the position of the IACV (214) while taking the ambient temperature into account.

[0059] In an example, without deviating from the scope of the present invention, for a particular start air temperature and air mass flow rate, the modelled engine oil temperature indicative of temperature of engine oil within the sump of the engine (112) is calculated as follows:Tmodel (t )=Tmodel(tl) + Tcoeff (tl) ... (1)

[0060] Here, t2 is the time instance at which the modelled engine oil temperature needs to be calculated and ti is the previous time instance for which, the modelled engine oil temperature is known. Tmodei (ti) is modelled engine oil temperature at a time instance (ti) and Tcoeff is temperature coefficient. Tcoeff is determined based on the start air temperature and air mass flow rate entering the engine (112) at time instance (ti).

[0061] Within the above expression (1), Tmodei(ti) value is a pre-calculated value and can be stored within the memory unit (203) associated with the controller (202). The modelled engine oil temperature is initialized by defining values of the modelled engine oil temperature at the start of the engine (Tmodei (to)). Each time when the modelled engine oil temperature is calculated, the corresponding value of the modelled engine oil temperature can be stored in the memory unit (203). Further, Tcoeff values are predefined values across various start air temperature values and air mass flow rates. These values can be stored within the memory unit (203) associated with the controller (202), often organized as a look-up table. To illustrate, while not limiting the scope of the present invention, consider the representation provided in the subsequent Table 1. Table 1 illustrates Tcoeff values at different start air temperature values and different air mass flow rates.Table 1

[0062] For example, without deviating from the scope of the present invention, modelled engine oil temperature (Tmodei (to)) at the time of starting of engine (112) i.e. t=0 sec is 10°C. The air mass flow rate at time t=0 sec is 2.5 mg / tdc and start air temperature is 25°C. Tcoeff value can be obtained as 0.0412 corresponding to air mass flow rate of 2.5 mg / tdc and start air temperature of 25°C. The modelled engine oil temperature at t = 1 sec can be calculated as follows:Tmodei (tl sec)—Tmodel(t o sec) + Tcoeff (t 0 sec)= 10 + 0.0412= 10.0412°C

[0063] Similarly, if the air mass flow rate at time t = 1 sec is 6 mg / tdc and start air temperature is 25°C. Tcoeff value can be obtained as 0.0604 corresponding to air mass flow rate of 6 mg / tdc and start air temperature of 25°C. The modelled engine oil temperature at t = 2 sec can be calculated as follows:Tmodei (t2 sec)—Tmodei (t 1 sec ) + Tcoeff (t 1 sec)= 10.0412 + 0.0604= 10.1016°C

[0064] It is crucial to recognize that in the presented Table 1, predefined values of Tcoeff are exemplified for selected temperature instances and the air mass flow rate. However, it’s important to acknowledge that such predefined values of TCOeff may be detailed for a more intricate spectrum of temperature values and air mass flow rates. For instance, for each integral temperature value in °C and each integral air mass flow rate, corresponding TCOeff values can be delineated. Consequently, upon the controller (202) accessing the start air temperature and accessing the mass flow rates, the correlated TCOeff for the detected start air temperature (ornearest integral temperature) and the air mass flow rate can be referenced from the look-up table. By employing the aforementioned expression (1), the desired modelled engine oil temperature intended for the time instance (t2) can be effectively calculated, facilitating the effective controlling of the position of idle air control valve (IACV).

[0065] In another embodiment, where TCOeff values are accessible solely at specific integral temperature points and specific air mass flow rate, the values of TCOeff at the specific number of air mass flow rates for intervening temperatures (for example, for detected start air temperature (t)) can be determined through established interpolation techniques. To elucidate, while refraining from constraining the scope of the present invention, the calculation of TCOeff can be facilitated using the subsequent interpolation expression (3):

[0066] Here, Yn denotes Tcoeff at the desired start air temperature (Tn), Y(n-l) represents the known Tcoeff values at the start air temperature T(n-l) immediately preceding Tn in the lookup table 1, and Y(n+1) signifies the known TCOeff values at start air temperature T(n+1) immediately following Tn in the Table 1. In the above expression (3), the air mass flow rate is the same for all the terms Tn, T(n-l), T(n+1), Yn, Y(n-l), and Y(n+1).

[0067] For instance, in a scenario for a specific number of air mass flow rate, where Tcoeff values are available for temperature values documented in Table 1, the TCOeff value for a detected start air temperature of 20 °C and air mass flow rate of 2.5 mg / tdc can be computed as follows:Tcoeff @20 °c =0.0412 + (20 - 10) * (0.0412 - 0.0412) / (25 - 10) =0.0412

[0068] Similarly, the above interpolation techniques can be implemented for the calculation of values of 0.000412 at the specific start air temperature and intervening air mass flow rate.

[0069] At step (308), the method (300) involves controlling an opening of the idle air control valve (IACV) based on the modelled engine oil temperature. Upon determination of the modelled engine oil temperature, the control may determine the position value for IACV (214) corresponding to modelled engine oil temperature. The controller (202) may then transmit the determined position value to the IACV (214) to adjust its position to allow controlled amount of air entering the engine (112).

[0070] Referring to FIG. 4, a flow diagram illustrates a method 400 for controlling an idle air control valve (IACV) for an engine (112), according to another embodiment of the present invention. This method (400) is executed by a controller, such as the controller (202).

[0071] At step (402), the method (400) includes the controller (202) accessing a start air temperature indicative of an atmospheric air temperature when the engine (112) starts.

[0072] At step (404), the method (400) includes the controller (202) accessing an air mass flow rate entering the engine (112). In particular, the controller (202) utilizes data from the TMAP sensor (218) present in the system (200) to ascertain the air mass flow rate.

[0073] At step (406), the method (400) includes the controller (202) accessing an engine oil temperature from an engine oil temperature (EOT) sensor at the time instance (t2). The engine oil temperature is indicative of temperature of engine oil at head of the engine (112).

[0074] Moving to step (408), the method (400) includes the controller (202) checking (408) whether the engine oil temperature (as accessed from EOT sensor (220)) is below the predefined threshold. In a particular example, this checking is triggered specifically when the engine oil temperature deviates from its true value such as during cold ambient temperature or during warm-up phase of the engine especially in the case of a vehicle utilizing the engine (112). This step is performed as a deviation between the EOT sensor reading and the modelled engine oil temperature occurs only when the EOT sensor reading falls below the predefined threshold, as depicted in FIG. 2B. Once the EOT sensor reading reaches the predefined threshold value, there is no deviation, indicating that the EOT sensor reading aligns with the modelled engine oil temperature. FIG. 2B shows an operating point where EOT sensor reading starts matching with the modelled engine oil temperature, which corresponds to a predefined threshold.

[0075] If the controller (202) confirms the engine oil temperature falling below the predefined threshold, the method (400) proceeds to step (410). Otherwise, the method (400) continues to persist with step (408), intermittently or continuously checking for the engine oil temperature falling below the predefined threshold.

[0076] It is essential to emphasize that the steps (402), (404), (406) and (408) can be executed concurrently, with potential overlap or in any sequence as deemed appropriate.

[0077] At step (410), the method (400) includes the controller (202) determining a modelled engine oil temperature when the engine oil temperature measured by the EOT sensor (220) is below the predefined threshold. The modelled engine oil temperature is indicative of a temperature of engine oil within a sump of the engine (112). The determination of the modelled engine oil temperature is based at least on the start air temperature, and the air mass flow rateas described.

[0078] Upon determination of the modelled engine oil temperature, the method (400) includes controlling an opening of the idle air control valve (IACV) (214) based on the modelled engine oil temperature at step (420). The step (420) includes further sub-steps (412), (414), (416), and (418).

[0079] At step (412), the method (400) includes the controller (202) determining a position value or a step count of the IACV (IACVEOT) corresponding to the accessed engine oil temperature at the time instance (t2). The position values (IACVEOT) are predefined values across different accessed engine oil temperatures. These values can be stored within the memory unit (203) associated with the controller (202), organized as a look-up table. To illustrate, while not limiting the scope of the present invention, consider the representation provided in the subsequent Table 2. Table 2 illustrates offset values at different modelled engine oil temperatures.able 2

[0080] It is important to note that in the presented Table 2, predefined position values (IACVEOT) are exemplified for selected temperature instances. However, it’s important to acknowledge that such predefined position values may be detailed for a more intricate spectrum of temperature values. For instance, for each integral temperature value in °C, corresponding position values (IACVEOT) can be delineated. Consequently, upon the controller (202) accessing the engine oil temperature, the corresponding position values (IACVEOT) for the accessed engine oil temperature can be referenced from the look-up table.

[0081] In another embodiment, where are accessible solely at specific accessed engine oil temperatures, the position values (IACVEOT) for intervening accessed engine oil temperatures can be determined through established interpolation techniques.

[0082] At step (414), the method (400) includes the controller (202) determining an offset value (IACVOEFSET) corresponding to the modelled engine oil temperature for the time instance (t2). The offset values (IACVOFFSET) are predefined values across different modelled engine oil temperature. These values can be stored within the memory unit (203) associated with the controller (202), often organized as a look-up table. To illustrate, while not limiting the scope of the present invention, consider the representation provided in the subsequent Table 3.Table 3 illustrates offset values at different modelled engine oil temperatures.Table 3

[0083] It is important to note that in the presented Table 3, predefined offset values (IACVOFFSET) are exemplified for selected temperature instances. However, it’s important to acknowledge that such predefined offset values may be detailed for a more intricate spectrum of temperature values. For instance, for each integral temperature value in °C, corresponding offset values (IACVOFFSET) can be delineated. Consequently, upon the controller (202) determining the modelled engine oil temperature, the corresponding offset values (IACVOFFSET) for the determined modelled engine oil temperature can be referenced from the look-up table.

[0084] In another embodiment, where are accessible solely at specific modelled engine oil temperatures, the offset values (IACVOFFSET) for intervening modelled engine oil temperatures can be determined through established interpolation techniques.

[0085] At step (416), the method (400) includes the controller (202) determining a corrective position value for the IACV (IACVCORRECTIVE) for the time instance (t2) based on the position value (IACVEOT) and the offset value (IACVOFFSET). The position value (IACVEOT) and the offset value (IACVOFFSET) should also correspond to time instance (t2). The corrective position value of the IACV (IACVCORRECTIVE) at the time instance (t2) is determined as:IACVCORRECTIVE = IACVOFFSET + IACVEOT . . . (2)For example, if the position value or step count for the IACV (IACVEOT) based on the engine oil temperature, accessed through the EOT sensor (220), is 62. The offset value (IACVOFFSET) can be obtained as (-12) corresponding to modelled engine oil temperature. Then the corrective position value of the IACV (IACVCORRECTIVE) can be computed as:IACVCORRECTIVE = (-12) + (50) = 38 stepsThus, the position value or the step value for the IACV has been corrected from 50 to 38.

[0086] At step (418), the method (400) includes the controller (202) controlling the opening of the idle air control valve (IACV) at time instance (t2) by adjusting a position of the IACV (214) according to the determined corrective position value (IACVCORRECTIVE). In an embodiment, upon determination of the corrective position value, the controller (202) may transmit a signal to IACV (214) to adjust the position of the IACV (214) according to the corrective position value (IACVCORRECTIVE).

[0087] FIG. 5 illustrates a graphical representation (500) showing variation of the corrective position value for the IACV (IACVCORRECTIVE) for different ambient temperatures, according to an embodiment of the present invention. FIG. 5 shows variation in position values of IACV (214) while keeping engine oil temperature accessed through the EOT sensor (220) at 60°C. The relationship between ambient temperature, the position value of the Idle Air Control Valve (IACV), and the amount of air entering the engine is crucial for understanding how an engine adjusts to environmental conditions. As ambient temperature rises, the surrounding air becomes warmer. This increase in temperature affects the density and properties of the air entering the engine's intake system. In response to these changes, the engine's control system modulates the IACV to maintain optimal air-to-fuel ratios for combustion. By allowing more air to engine through the IACV, the engine compensates for the decreased air density caused by higher ambient temperatures. This adjustment ensures that the engine receives an appropriate amount of air for combustion, preventing issues such as stalling or rough idling. Thus, the present invention incorporates such variations in position values based on ambient temperature to determine optimal settings for controlling the Idle Air Control Valve (IACV) opening, as described above.

[0088] Hence, multiple embodiments of the present invention offer a proficient approach to controlling opening of idle air control valve (IACV), applicable to both vehicular and non-vehicular contexts. The selection of TCOeff values and offset values is strategically executed to incorporate the ambient temperature into account while controlling the operation of the idle air control valve. Such intelligent selection of TCOeff and offset values engenders distinct engine oil temperatures across varying ambient temperatures during cold ambient and engine in warm-up phase, which ensures the optimum selection of the position value for the IACV For instance, the position value required for stable speed at a lower ambient temperature is set to be more than or equal to the position value at a higher ambient temperature. In other words, the substantially higher position value or step count for IACV at high ambient temperature allows more air to enter the engine, which causes the combustion process to continue without any interruption. Further, when the ambient temperature is within the predefined threshold, the method triggers determination of the correction position value which is consistent across different ambient temperatures. Thus, by intelligently optimizing the position values, the embodiments detailed in this disclosure safeguard the vehicle speed within an optimal range. In effect, the present invention adeptly addresses challenges posed by deviation observed between sump oil temperature and oil in head gallery temperature, while improving the stability of the vehicle.

[0089] While few embodiments of the present invention have been described above, it is to be understood that the invention is not limited to the above embodiments and modifications may be appropriately made thereto within the spirit and scope of the invention.

[0090] While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the invention herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

Claims

CLAIMS

1. A method (300, 400) of controlling an idle air control valve (IACV) (214) for an engine (112), the method (300, 400) comprising: accessing (302, 402), by a controller (202), a start air temperature indicative of an atmospheric air temperature when the engine (112) starts; accessing (304, 404), by the controller (202), an air mass flow rate entering the engine (112); determining (306, 410), by the controller (202), a modelled engine oil temperature at least based on the start air temperature, and the air mass flow rate, wherein the modelled engine oil temperature is indicative of temperature of engine oil within a sump of the engine (112); and controlling (308, 420), by the controller (202), an opening of the idle air control valve (IACV) (214) based on the modelled engine oil temperature.

2. The method (300, 400) as claimed in claim 1, wherein accessing (304, 404) the air mass flow rate comprises accessing the air mass flow rate entering the engine (112) at a time instance (ti), and wherein determining (306, 410) the modelled engine oil temperature comprises calculating the modelled engine oil temperature for a time instance (ti) based on the air mass flow rate entering the engine (112) at the time instance (ti), the start air temperature, and the modelled temperature at the time instance (ti), wherein the time instance (ti) is higher than the time instance (ti).

3. The method (400) as claimed in claim 1, wherein controlling (308, 420) the opening of the idle air control valve (IACV) (214) comprises: accessing (406), by the controller (202), an engine oil temperature from an engine oil temperature (EOT) sensor at the time instance (tz), wherein the engine oil temperature is indicative of temperature of engine oil at head of the engine (112); determining (412), by the controller (202), a position value of the IACV (IACVEOT) corresponding to the accessed engine oil temperature at the time instance (ti); determining (414), by the controller (202), an offset value (IACVOFFSET) corresponding to the modelled engine oil temperature for the time instance (ti);determining (416), by the controller (202), a corrective position value for the IACV (IACVCORRECTIVE) for the time instance (ti) based on the position value (IACVEOT) and the offset value (IACVOFFSET); and controlling (418), by the controller (202), the opening of the idle air control valve (IACV) (214) at time instance (ti) by adjusting a position of the IACV (214) according to the determined corrective position value (IACVCORRECTIVE).

4. The method (300, 400) as claimed in claim 2, wherein the modelled engine oil temperature for time instance (ti) is calculated based on a coefficient factor stored in a prestored look-up table, wherein the coefficient factor corresponds to the air mass flow rate entering the engine (112) at the time instance (ti) and the start air temperature.

5. The method (300, 400) as claimed in claim 1, wherein accessing (302, 402) a start air temperature comprises receiving a signal from one of: an ambient sensor coupled to the controller (202); or a Temperature Manifold Absolute Pressure (TMAP) sensor located at an intake manifold (222).

6. The method (300, 400) as claimed in claim 1, wherein accessing (302, 402) the air mass flow rate entering into the engine (112) comprises receiving a signal from a Temperature Manifold Absolute Pressure (TMAP) sensor located at an intake manifold (222).

7. The method (300, 400) as claimed in claim 3, wherein the corrective position value of the IACV (IACVCORRECTIVE) is determined as:IACVCORRECTIVE = IACVOFFSET + IACVEOT.

8. The method (300, 400) as claimed in claim 3, wherein the offset value (IACVOFFSET) corresponding to the modelled engine oil temperature and a position value of the IACV (IACVEOT) corresponding to the accessed engine oil temperature are determined through a respective pre-stored lookup table.

9. The method (300, 400) as claimed in claim 3, comprising: checking (408) whether the accessed engine oil temperature is less than a predefined threshold,wherein the modelled engine oil temperature is determined when the accessed engine oil temperature is less than a predefined threshold.

10. The method (300, 400) as claimed in claim 3, wherein the offset value corresponds to a deviation between the engine oil temperature and the modelled engine oil temperature.

11. A vehicle (100) comprising: an engine (112); an idle air control valve (IACV) (214) configured to control an amount of air entering into the engine (112); and a controller (202) configured to execute machine-readable instructions to perform, at least in part, to: access a start air temperature indicative of an atmospheric air temperature when the engine (112) starts; access an air mass flow rate entering the engine (112); determine a modelled engine oil temperature at least based on the start air temperature and the air mass flow rate, wherein the modelled engine oil temperature is indicative of temperature of engine oil within a sump of the engine (112); and control an opening of the idle air control valve (IACV) (214) based on the modelled engine oil temperature.

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