A carburetor throttle control method

Abstract

The application discloses a carburetor throttle control method and relates to the technical field of carburetor throttle control. A real-time pitch angle is acquired through an angle sensor, a theoretical displacement amount is calculated in combination with an equivalent arm length calculation theory of a float chamber structure, a horizontal height difference is determined according to a difference between a relative reference height of a main nozzle top end and a relative reference height of a static liquid level, an additional submerged liquid level displacement is obtained through comparison between the theoretical displacement amount and the horizontal height difference, and whether unilateral out-of-boundary occurs is determined in this way. When the additional submerged liquid level displacement is zero, a reference driving differential pressure is calculated. When the additional submerged liquid level displacement is greater than zero, an additional liquid level head is calculated, and a target float chamber pressure is determined. Air supplement flow is calculated based on a fixed micro-hole area, release flow is calculated in combination with the target float chamber pressure and a variable hole area, the variable hole area is solved through flow balance, and the variable hole opening degree is adjusted through a stepping motor, so that the problem that fuel mixing is enriched due to unilateral out-of-boundary of the carburetor under a continuous downhill working condition is solved.

Description

Technical Field

[0001] This invention relates to the field of carburetor throttle control technology, and more specifically to a carburetor throttle control method. Background Technology

[0002] The carburetor is the core fuel control component of small fuel-powered devices. Its main function is to adjust the fuel-air mixing ratio, i.e., the air-fuel ratio, according to the engine operating conditions, so as to ensure that the engine outputs stable power and burns efficiently at different stages. Under level driving conditions or short periods of smooth road conditions, manufacturers calibrate the static liquid level height of the float chamber, the relative position of the top of the main nozzle and the reference surface, and combine the pressure relationship between the float chamber and the main nozzle's neighborhood to establish a stable mapping relationship between the difference between atmospheric pressure and the reference pressure in the main nozzle's neighborhood, i.e., the reference driving differential pressure and the air-fuel ratio. This ensures that the liquid level in the float chamber and the top of the main nozzle maintain a fixed horizontal height difference, allowing emulsified air to enter smoothly and the air-fuel ratio to remain within the ideal range. However, in actual applications, vehicles often need to experience pitching and rolling conditions lasting tens of seconds to several minutes on mountain roads, winding mountain highways, etc. At this time, the free liquid level inside the float chamber will generate a theoretical forward displacement as the vehicle tilts. When this displacement exceeds the horizontal height difference, the liquid level will rise additionally relative to the top of the main nozzle, forming an additional submerged liquid level displacement, or even partially or completely submerging the emulsified air hole next to the main nozzle, breaking the liquid level pressure intake balance under level conditions.

[0003] Under sustained downhill pitch conditions, traditional carburetors suffer from a core technical problem: they cannot actively compensate for the imbalance within the carburetor induced by the attitude, leading to a continuously rich fuel mixture that severely impacts throttle control stability and driving safety. Traditional carburetors rely solely on the mechanical characteristics of the float mechanism to passively adjust the fuel level or control the intake volume solely through throttle opening. They fail to consider the impact of continuous pitch angle on the carburetor's fuel level head pressure difference and the coupling relationship between emulsified air intake and fuel level. Furthermore, the fuel level submerging the emulsification air orifice obstructs air intake and weakens the emulsification effect. Moreover, traditional carburetors lack an active mechanism for adjusting the float chamber pressure, making it impossible to offset additional effects by changing the pressure in the air chamber above the float chamber. This directly manifests as a significantly richer air-fuel ratio at the same low throttle opening, resulting in sluggish cruising and fluctuating power output. If the downhill duration is prolonged or the slope is steep, it can also cause engine stalling during coasting or a power shock during restart, severely compromising the predictability of throttle control. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a carburetor throttle control method that solves the problem of its inability to actively compensate for attitude-induced disruption of the carburetor's internal balance, leading to continuous enrichment of the fuel mixture.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The additional submerged liquid level displacement is obtained, which is the additional displacement of the liquid level in the vehicle float chamber relative to the top of the main nozzle.

[0007] When the additional immersion level displacement is 0, the difference between atmospheric pressure and the reference pressure in the vicinity of the main nozzle is marked as the reference drive differential pressure. The reference pressure in the vicinity of the main nozzle is the gas pressure in the cavity space next to the main nozzle and connected to the emulsified air hole when the vehicle is parked horizontally.

[0008] Obtain the fuel density of the fuel used by the carburetor. When the additional immersion level displacement is greater than 0, multiply the fuel density by the gravitational acceleration and then by the additional immersion level displacement. The product is marked as the additional level head. The additional level head is the pressure increment caused by the additional displacement of the float chamber liquid level when the vehicle goes downhill.

[0009] When the additional immersion level displacement is greater than 0, the value obtained by adding the real-time main nozzle pressure to the reference drive differential pressure and then subtracting the additional level head is marked as the target float chamber pressure. The real-time main nozzle pressure is the gas pressure in the cavity space connected to the emulsified air hole next to the main nozzle when the vehicle is going downhill. The target float chamber pressure is the target pressure value that the float chamber needs to be adjusted to achieve.

[0010] Furthermore, the area A of the fixed micropores connecting the air cavity above the float chamber to the atmosphere is obtained. t Obtain the low-pressure reference zone pressure P S The low-pressure reference zone pressure is the pressure in the area connected to the variable orifice of the air chamber above the float chamber;

[0011] Based on atmospheric pressure, target float chamber pressure, and fixed micropore area A t The atmospheric refueling flow rate for the float chamber is calculated as follows:

[0012] ;

[0013] Q t A is the air supply flow rate from the atmosphere to the float chamber. t To fix the micropore area, P a Atmospheric pressure, P b For the target float chamber pressure, P a -P b For pressure difference;

[0014] The air supply flow rate from the atmosphere to the float chamber is the flow rate of gas drawn into the float chamber from the atmosphere through fixed micro-holes.

[0015] Furthermore, based on the target float chamber pressure and the low-pressure reference zone pressure P S and variable aperture area A s The discharge flow rate from the float chamber to the low-pressure reference is calculated as follows:

[0016] ;

[0017] Q s A is the discharge flow rate from the float chamber to the low-pressure reference. s For the variable aperture area, P b For the target float chamber pressure, P S For the low-pressure reference zone pressure, P b -P s For pressure difference;

[0018] The discharge flow rate from the float chamber to the low-pressure reference is the flow rate of gas discharged from the float chamber to the low-pressure reference zone through the variable orifice;

[0019] The variable orifice area A of the adjustable orifice, which connects the air chamber above the float chamber to the low-pressure reference region, is calculated by jointly determining the air supply flow rate from the atmosphere to the float chamber and the discharge flow rate from the float chamber to the low-pressure reference region. s .

[0020] Furthermore, the real-time pitch angle is obtained through the vehicle's angle sensor, which is the tilt angle of the vehicle in the forward and backward direction.

[0021] Obtain the relative reference height of the top of the main nozzle. The main nozzle is the main channel through which the emulsified fuel-air mixture is injected into the throat. The relative reference height of the top of the main nozzle is the height of the top of the main nozzle in the carburetor relative to the preset reference surface of the carburetor.

[0022] Obtain the static liquid level relative reference height, which is the height of the static liquid level of the fuel in the float chamber relative to the preset reference surface when the vehicle is parked horizontally;

[0023] Obtain the equivalent arm length determined by the float chamber structure. The equivalent arm length is the equivalent displacement scale of the fuel level in the float chamber when the vehicle tilts forward and backward.

[0024] The product obtained by multiplying the equivalent arm length by the tangent of the real-time pitch angle absolute value is marked as the theoretical displacement, which is the theoretical displacement of the liquid surface caused by the vehicle tilting.

[0025] Furthermore, the difference between the relative height of the main nozzle tip and the relative height of the static liquid level is marked as the horizontal height difference, which is the height difference between the main nozzle tip and the static liquid level in a horizontal attitude.

[0026] Furthermore, the difference between the theoretical displacement and the horizontal height difference is obtained. This difference is then compared with the value 0. The maximum value between the difference and the value 0 is taken and marked as the additional submerged liquid level displacement. The additional submerged liquid level displacement is used to determine whether a unilateral boundary breach has occurred.

[0027] When the additional submerged liquid level displacement is greater than 0, it is determined that a single-sided cross-boundary has occurred. A single-sided cross-boundary occurs when the vehicle is continuously going downhill, and the float chamber liquid level is submerged relative to the top of the main nozzle due to the unidirectional pitch attitude of the carburetor, which causes air intake to be blocked, resulting in the continuous enrichment of fuel mixture at the same small throttle opening.

[0028] Furthermore, a pressure measuring point is preset in the cavity space next to the main nozzle and connected to the emulsified air hole. A pressure sensor is installed at the preset pressure measuring point. When the additional immersion liquid level displacement is 0, the pressure value read is marked as the reference pressure of the main nozzle neighborhood. When the additional immersion liquid level displacement is greater than 0, the pressure value read is marked as the real-time main nozzle pressure.

[0029] Furthermore, the variable orifice area A is solved by jointly calculating the air supply flow rate from the atmosphere to the float chamber and the discharge flow rate from the float chamber to the low-pressure reference. s ,include:

[0030] Based on the fact that the air supply flow rate from the atmosphere to the float chamber is equal to the air discharge flow rate from the float chamber to the low-pressure reference, the variable orifice area A can be calculated. s The details are as follows:

[0031] ;

[0032] Where A s The area is the variable aperture.

[0033] Furthermore, when the additional immersion liquid level displacement is greater than 0, the opening of the variable orifice connecting the upper cavity of the float chamber to the low-pressure reference zone is adjusted by a stepper motor to the calculated variable orifice area A. s The corresponding geometric area.

[0034] Furthermore, the numerical change of the additional immersion liquid level displacement is received and monitored in real time. If the value of the additional immersion liquid level displacement changes from greater than 0 to 0, it is determined that the unilateral boundary breach has been resolved, and the variable orifice area A is adjusted accordingly. s The variable aperture connecting the upper chamber of the float chamber to the low-pressure reference area is set to 0 and adjusted to 0 via a stepper motor.

[0035] Compared with existing technologies, it has the following advantages:

[0036] This solution proposes a carburetor throttle control method that solves the problem of traditional carburetors' inability to accurately identify abnormal fluid level displacement during continuous downhill driving by constructing a unilateral over-limit judgment mechanism based on geometric parameters and attitude coupling. The solution obtains the real-time pitch angle using a vehicle angle sensor, calculates the theoretical displacement by combining it with the carburetor's inherent parameter, equivalent arm length, and then determines the horizontal height difference by comparing the difference between the top of the main nozzle and the static fluid level relative to the reference height. Finally, the difference between the theoretical displacement and the horizontal height difference is compared with zero to obtain the additional submerged fluid level displacement, thus achieving quantitative judgment of unilateral over-limit. This judgment method considers both the float chamber structural characteristics and real-time attitude changes, accurately capturing the submersion state of the fluid surface relative to the top of the main nozzle during continuous downhill driving. This avoids false triggering due to attitude fluctuations or missed triggering due to insufficient over-limit, providing accurate triggering basis for subsequent control.

[0037] By establishing an active pressure compensation logic, the impact of the additional liquid level head is effectively resolved, thereby offsetting unilateral overflow and addressing the core issue of continuous enrichment of the air-fuel ratio in traditional carburetors. The solution first obtains the reference pressure in the main nozzle neighborhood and calculates the reference drive differential pressure when the additional submerged liquid level displacement is zero. When unilateral overflow occurs, the additional liquid level head is calculated by combining fuel density, gravitational acceleration, and the additional submerged liquid level displacement. Then, the target float chamber pressure is determined by the relationship between the real-time main nozzle pressure reference drive differential pressure and the additional liquid level head. This calculation logic transforms liquid level changes into quantifiable pressure compensation quantities, giving float chamber pressure adjustment a clear target. It ensures that the equivalent drive head of the float chamber and the main nozzle neighborhood returns to the horizontal operating condition reference after adjustment, fundamentally solving the problems of increased fuel injection power and insufficient emulsified air caused by additional liquid level rise, and maintaining a stable air-fuel ratio.

[0038] Precise and stable regulation of the float chamber pressure is achieved through the coordinated operation of flow balance control and stepper motor execution. The scheme calculates the replenishment flow rate based on the target float chamber pressure at atmospheric pressure and the fixed micro-orifice area, and calculates the discharge flow rate by combining the target float chamber pressure with the low-pressure reference zone pressure and the variable orifice area. The variable orifice area is then calculated by finding the equality between these two values, and the stepper motor adjusts the variable orifice opening to the corresponding geometric area. This process ensures that the float chamber pressure stably converges to the target value through flow balance, avoiding repeated mixing ratio fluctuations caused by pressure volatility. Simultaneously, the precise execution of the stepper motor guarantees adjustment accuracy, providing higher control stability compared to traditional mechanical passive adjustment. This ensures the predictability of the throttle opening and engine torque mapping relationship under different road conditions, improving vehicle driving safety and handling stability. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0040] Figure 2 This is a flowchart illustrating the variable orifice area calculation process of the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] First Embodiment

[0043] This application provides a carburetor throttle control method;

[0044] As an embodiment of this application, the method specifically includes:

[0045] The additional submerged liquid level displacement is obtained, which is the additional displacement of the liquid level in the vehicle float chamber relative to the top of the main nozzle.

[0046] When the additional immersion level displacement is 0, the difference between atmospheric pressure and the reference pressure in the vicinity of the main nozzle is marked as the reference drive differential pressure. The reference pressure in the vicinity of the main nozzle is the gas pressure in the cavity space next to the main nozzle and connected to the emulsified air hole when the vehicle is parked horizontally.

[0047] Obtain the fuel density of the fuel used by the carburetor. When the additional immersion level displacement is greater than 0, multiply the fuel density by the gravitational acceleration and then by the additional immersion level displacement. The product is marked as the additional level head. The additional level head is the pressure increment caused by the additional displacement of the float chamber liquid level when the vehicle goes downhill.

[0048] When the additional immersion level displacement is greater than 0, the value obtained by adding the real-time main nozzle pressure to the reference drive differential pressure and then subtracting the additional level head is marked as the target float chamber pressure. The real-time main nozzle pressure is the gas pressure in the cavity space connected to the emulsified air hole next to the main nozzle when the vehicle is going downhill. The target float chamber pressure is the target pressure value that the float chamber needs to be adjusted to achieve.

[0049] Second Embodiment

[0050] As a second embodiment of this application, this embodiment is implemented based on the first embodiment. Please refer to [link / reference]. Figure 1 The method provided in this embodiment includes the following steps:

[0051] Step 1: Obtain the real-time pitch angle using the motorcycle's angle sensor. The real-time pitch angle reflects the motorcycle's tilt angle in the forward and backward directions. When going downhill, the front of the motorcycle points downwards, and the pitch angle is a negative value. In subsequent calculations, the absolute value of the real-time pitch angle is used to represent the degree of tilt when going downhill. Obtain the relative reference height of the top of the main nozzle using assembly measuring tools such as calipers and height gauges, or from the design drawings. The main nozzle is the main channel for spraying the emulsified fuel-air mixture into the throat. The relative reference height of the top of the main nozzle is the height of the top of the main nozzle relative to a certain preset reference plane in the carburetor, that is, the distance from the reference plane upwards to the top of the main nozzle. The reference plane is a unified reference plane artificially selected during carburetor analysis and design, used for calibration. The relative height of key components inside the carburetor provides a common zero-point reference for the height relationship of each component. When the vehicle is parked horizontally, the fuel level in the float chamber will remain stable under the balancing action of the float mechanism. The float controls the fuel inlet to maintain the fuel level at the designed static height. At this time, the static liquid level relative reference height is obtained through measurement or theoretical calculation or simulation during the design phase. The static liquid level relative reference height is the height of the static fuel level in the float chamber relative to the same preset reference plane when the vehicle is parked horizontally. The equivalent arm length is obtained. The equivalent arm length is a simplified length parameter determined by the shape and structure of the float chamber, which reflects the equivalent displacement scale of the fuel level displacement when the vehicle tilts forward or backward.

[0052] S11. The product obtained by multiplying the equivalent arm length by the tangent of the real-time pitch angle absolute value is marked as the theoretical displacement. The theoretical displacement is generated by the free liquid surface in the float chamber as the vehicle tilts forward and backward. The tangent of the real-time pitch angle absolute value reflects the proportional relationship between the liquid surface displacement corresponding to the tilt angle and the direction of the equivalent arm length. Therefore, multiplying the two can quantify the theoretical liquid surface displacement caused by the tilt.

[0053] S12. The difference between the relative height of the top of the main nozzle and the relative height of the static liquid level is marked as the horizontal height difference. The horizontal height difference is the height difference between the top of the main nozzle and the static liquid level in a horizontal posture, reflecting the vertical distance between the oil surface and the top of the nozzle when the vehicle is horizontal.

[0054] S13. Subtract the horizontal height difference from the theoretical displacement in S12 to obtain a difference value. Compare this difference value with 0 (0 is zero). Take the maximum value between the difference and 0. Mark the maximum value as the additional submerged liquid level displacement. The additional submerged liquid level displacement is used to determine whether a unilateral boundary breach has occurred. If the additional submerged liquid level displacement > 0, a unilateral boundary breach has occurred. The magnitude of the additional submerged liquid level displacement directly reflects the intensity of the unilateral boundary breach, providing a quantitative basis for pressure correction in subsequent steps. If the difference value is negative, it means that the tilt did not submerge the air holes near the nozzle. In this case, the additional submerged displacement is zero. If the difference value is positive, it means that the liquid level rose additionally due to the tilt. This positive value is the amount of additional submerged displacement. Specifically, assume that when the vehicle is going downhill, the real-time pitch angle is -5°, and the top of the main nozzle is relative to the reference. With a height of 10mm, a static liquid level relative to the reference height of 8mm, and an equivalent arm length of 20mm, the difference calculated in S13 is -0.25mm. Therefore, the additional submerged liquid level displacement is taken as 0, indicating no unilateral boundary violation. Pressure correction will not be triggered subsequently. If the difference calculated in S13 is positive, it is considered a unilateral boundary violation, and pressure correction needs to be initiated subsequently. Unilateral boundary violation refers to a situation where, when the vehicle is continuously going downhill, the carburetor, due to its unilateral pitch attitude (e.g., the front of the vehicle tilts downward), causes a significant abnormality in the submersion relationship between the free liquid surface of the float chamber and the top of the main nozzle in the downhill direction. Originally, in a horizontal position, the liquid surface did not submerge the air entry channel, but when going downhill, the liquid surface moves forward and rises, thus submerging or partially submerging the channel, causing air entry to be obstructed. Ultimately, this results in the fuel mixture becoming continuously rich at the same small throttle opening, i.e., the air-fuel ratio is too rich.

[0055] Specifically, by precisely quantifying the degree of unilateral overflow of the float chamber liquid level during downhill driving, clear numerical criteria are provided for subsequent steps, enabling targeted triggering conditions and intensity basis for subsequent pressure control. Through the coupling of geometric parameters and pitch angle, a quantitative formula for additional submerged liquid level displacement is constructed, transforming the complex relationship between attitude and liquid level into a calculable scalar. This breaks through the limitation of traditional carburetors relying solely on horizontal attitude calibration, providing a quantitative triggering basis for active control of the mixture ratio under non-horizontal attitude conditions.

[0056] Step Two: Pre-set pressure measurement points in the cavity space surrounding the main nozzle nozzle and connecting to the emulsified air orifice, and install pressure sensors, such as micro-pressure sensors. The pressure sensors detect changes in gas pressure at the measurement points, converting the pressure signal into an electrical signal, which is then read as a specific pressure value by the acquisition system. This pressure value is marked as the main nozzle neighborhood reference pressure. The main nozzle neighborhood reference pressure is only collected when the additional immersion liquid level displacement is 0. The main nozzle neighborhood reference pressure refers to the gas pressure in the area near the main nozzle when the carburetor is in a horizontal position and there is no unilateral boundary breach. It reflects the pressure near the main nozzle under the normal operating conditions specified in the design calibration of the carburetor. The power state and air-fuel mixture ratio of the carburetor are jointly determined by the pressure corresponding to the liquid level height, the amount of emulsified air, and the nozzle geometry. The pressure in the vicinity of the main nozzle is a key factor affecting the amount of emulsified air and the fuel injection power. The pressure difference drives air into the emulsified zone and pushes fuel out through the nozzle. Measuring the reference pressure in the vicinity of the main nozzle under stable horizontal conditions is to obtain a pressure reference for the reference state. When a single-sided overrun occurs on a downhill slope, the mixture ratio will become abnormally rich due to the change in liquid level. It is necessary to compensate by adjusting the float chamber pressure. At this time, the reference pressure in the vicinity of the main nozzle is the compensation scale to ensure that the mixture ratio can return to the normal state under horizontal conditions after correction.

[0057] When the additional submerged liquid level displacement is 0, the atmospheric pressure is obtained. The difference between the atmospheric pressure and the reference pressure in the vicinity of the main nozzle is marked as the reference driving differential pressure. The reference driving differential pressure represents the difference between the atmospheric pressure and the reference pressure in the vicinity of the main nozzle under horizontal attitude. It is the reference pressure difference that drives the fuel and air to mix when the carburetor is working normally and not crossing the boundary on one side. The value range of the reference driving differential pressure varies with the ambient atmospheric pressure and the structure of the carburetor. It is usually a positive pressure difference because the pressure in the vicinity of the main nozzle is slightly lower than the atmospheric pressure, thus ensuring that air can enter. Specifically, the reference driving differential pressure is the core reference quantity for the subsequent calculation of the target float chamber pressure. The subsequent steps need to calculate the target float chamber pressure to be adjusted based on the reference driving differential pressure and the additional liquid level head when crossing the boundary on the downhill slope, so as to offset the rich fuel effect brought by the downhill slope.

[0058] Specifically, by calculating the pressure difference, a benchmark for carburetor mixture control under horizontal attitude is obtained, providing a unified and traceable reference for subsequent pressure corrections and ensuring the accuracy and consistency of mixture correction. Assuming an ambient atmospheric pressure of 101 kPa and a stable operating condition with zero displacement of the additional immersion liquid level, the pressure sensor collects a reference pressure of 99 kPa in the vicinity of the main nozzle. The calculated reference drive differential pressure is then 2 kPa. When calculating the target float chamber pressure in subsequent steps, the reference drive differential pressure of 2 kPa will be used as a reference to adjust the float chamber pressure to match the reference drive state under horizontal attitude.

[0059] Step 3: Obtain the fuel density, which is the inherent density of the fuel used in the carburetor. Obtain the gravitational acceleration and the additional submerged liquid level displacement. When the additional submerged liquid level displacement is greater than 0, calculate the additional liquid head corresponding to the additional submerged liquid level displacement according to the hydrostatic pressure formula. This is the pressure increment caused by the additional rise in liquid level. Specifically: Additional liquid head = Fuel density × Gravitational acceleration × Additional submerged liquid level displacement. The additional liquid head represents the pressure increment corresponding to the additional rise in the float chamber liquid level when going downhill. Its value varies with the additional submerged liquid level displacement and is non-negative. Specifically, the additional liquid head quantifies the enrichment drive of the mixture caused by the additional liquid level due to going downhill, and is the core quantity that needs to be offset in subsequent pressure correction. Assuming the additional submerged liquid level displacement is 5mm and the fuel density is 750kg / m³, 3 The acceleration due to gravity is 9.8 m / s². 2 The calculated additional liquid level head is 0.037 kPa. 0.037 kPa is the pressure increment brought about by the additional liquid level. It needs to be offset by reducing the pressure in the float chamber. By converting the geometric liquid surface displacement into the physical pressure increment, a quantitative relationship is established between the geometric cause of oil-rich downhill and the pressure correction control method, providing a clear compensation target for subsequent pressure calculation.

[0060] The real-time main nozzle pressure is obtained by a pressure sensor in the cavity space connected to the emulsion air hole around the main nozzle nozzle. The real-time main nozzle pressure is the real-time gas pressure in the area near the emulsion pipe when the vehicle is going downhill and one side of the carburetor crosses the boundary. The method of obtaining the pressure is the same as that of obtaining the reference pressure in the neighborhood of the main nozzle. Essentially, it is the pressure value measured in the same target area under different operating conditions. When measuring the reference pressure in the neighborhood of the main nozzle, the sensor works under the stable operating condition of the vehicle being level and the carburetor not crossing the boundary on one side. The pressure collected is the reference pressure with a normal air-fuel mixture ratio. When measuring the real-time main nozzle pressure, the sensor works under the dynamic operating condition of the vehicle going downhill and the carburetor crossing the boundary on one side, i.e., the additional immersion liquid level displacement is >0. The pressure collected is the real-time pressure when the air-fuel mixture ratio is abnormally rich.

[0061] Based on the control principle that pressure head + level head = reference drive head, the target float chamber pressure is derived as follows: When a unilateral overshoot occurs (i.e., additional submerged liquid level displacement > 0), the real-time main nozzle pressure + reference drive differential pressure - additional liquid level head = target float chamber pressure. The target float chamber pressure is the target pressure value that the float chamber needs to be adjusted to achieve, used to drive the actuators in subsequent steps. It must be ensured that the adjusted float chamber pressure can offset the additional liquid level head. This is the sole target control quantity for the dual-reference pressure distribution execution in subsequent steps, to achieve the return of the total drive head to the horizontal reference. The calculated target float chamber pressure breaks through the limitations of the traditional carburetor's passive adaptation posture, completing a closed loop from downhill posture to geometric overshoot and then to active pressure correction. This ensures that the mixture ratio can be actively pulled back to the normal range when the downhill overshoot occurs. A control method of pressure head + liquid level head = reference drive head is proposed, which directly links the liquid level increment of geometric overshoot with pressure regulation. This breaks through the limitations of the traditional carburetor's passive adaptation posture relying solely on mechanical structure, realizing active and quantitative control of the mixture ratio under non-horizontal conditions, and significantly improving the stability and predictability of throttle control.

[0062] Step 4: The float chamber is the cavity in the carburetor that stores fuel and maintains a stable fuel level. It is the core component of the carburetor to achieve fuel-air mixing control. The carburetor determines the fuel injection drive head and mixture ratio by the fuel level height in the float chamber, the geometric relationship between the fuel level and the main nozzle, and the pressure state of the air chamber above the float chamber. The air chamber above the float chamber is simply referred to as the upper float chamber. The upper float chamber has a fixed micro-orifice that communicates with the atmosphere and a variable orifice that communicates with the low-pressure reference area. By balancing the flow of gas released to the low-pressure reference and gas replenished from the atmosphere, the pressure in the float chamber is adjusted, so that the pressure in the float chamber passively converges to the target value, thereby offsetting the rich fuel effect caused by going downhill and exceeding the limit.

[0063] Obtain the fixed micropore area A of the upper cavity of the float chamber t The fixed micro-orifice area is the area of ​​the fixed orifice connecting the upper chamber of the float chamber to the atmosphere. It is an inherent structural parameter determined during the design and manufacturing of the carburetor and can be obtained through drawing annotations or measurement with measuring tools. The low-pressure reference zone pressure P is obtained. S The low-pressure reference zone is the area connected to the variable orifice in the upper cavity of the float chamber, such as the inner cavity of the air filter box or next to the venturi tube. It is a low-pressure area near the carburetor. The pressure in the low-pressure reference zone is obtained as a reference standard for lowering the pressure in the float chamber.

[0064] Based on the fluid dynamics principle that the orifice flow rate is proportional to the square root of the pressure difference between the two ends, the flow rate Q released from the upper chamber of the float chamber to the low-pressure reference zone through the variable orifice can be calculated. s Equal to the flow rate Q of air supplied from the atmosphere to the upper chamber of the float chamber through the fixed micro-orifice. t The conclusion, namely Q s =Q t , Where Q is the flow rate, A is the orifice area, and ΔP is the pressure difference between the two ends of the orifice in the upper cavity of the float chamber. Specifically, this conclusion can be used to derive the variable orifice area A of the upper cavity of the float chamber. s Provide a theoretical basis to ensure that the pressure in the float chamber can passively converge to the target value through the flow balance of the dual-reference connection;

[0065] according to Solve for the variable orifice area A of the upper cavity of the float chamber. s The details are as follows:

[0066] ;

[0067] Q s A is the discharge flow rate from the float chamber to the low-pressure reference. s For the variable aperture area, P b For the target float chamber pressure, P S The pressure is the low-pressure reference zone pressure, and the pressure difference is P. b -P s ;

[0068] ;

[0069] Q t A is the air supply flow rate from the atmosphere to the float chamber. t To fix the micropore area, P a Atmospheric pressure, P b The target float chamber pressure is represented by the pressure difference P. a -P b ;

[0070] Due to Q s =Q t Therefore, the variable aperture area A can be calculated. s for:

[0071] ;

[0072] Specifically, the variable orifice area A of the upper cavity of the float chamber s The adjustable orifice area connecting the upper cavity of the float chamber to the low-pressure reference zone is determined by an actuator, such as a stepper motor, which adjusts the opening of the variable orifice to the calculated variable orifice area A. s The corresponding geometric area ensures that the float chamber pressure can converge to the target float chamber pressure P through flow balance. b This enables the physical execution of pressure correction.

[0073] Step 5: Receive and monitor the numerical change of the additional immersion liquid level displacement in real time, and determine whether the unilateral boundary breach has been resolved, i.e., determine whether the additional immersion liquid level displacement is 0. If the additional immersion liquid level displacement is 0, it is determined that the unilateral boundary breach has been resolved. At this time, the variable orifice area A connecting the upper cavity of the float chamber to the low-pressure reference area needs to be adjusted. s Setting it to 0 means closing the variable aperture, allowing the upper chamber of the float chamber to communicate with the atmosphere only through a fixed micro-aperture;

[0074] Specifically, the upper chamber of the float chamber is connected to the atmosphere only through a fixed micro-orifice. The pressure in the float chamber gradually approaches atmospheric pressure. Because the fixed micro-orifice maintains a steady-state connection with the atmosphere, the pressure difference disappears and balances with atmospheric pressure. The pressure difference between the float chamber and the main nozzle's adjacent area, and the pressure corresponding to the float chamber's liquid level, return to the baseline state of a horizontal posture. This allows the carburetor's fuel-air mixture ratio to return to the factory-calibrated normal range, thereby allowing the mapping relationship between throttle opening and engine torque to return to a predictable calibration range. This enables the carburetor to quickly return to the original factory-designed control logic after a single-sided overshoot is cleared, ensuring the consistency of throttle control and preparing for the monitoring and correction of the next downhill overshoot. This forms a closed-loop control exit and restart logic. For example, if the vehicle finishes going downhill and enters a flat road section, the additional submerged liquid level displacement calculated by S13 is 0, indicating that the liquid level no longer additionally submerges the nozzle. At this time, the variable orifice area A... s When set to 0, the float chamber is only vented to the atmosphere through a fixed micro-hole. The pressure gradually equals atmospheric pressure. The pressure difference in the vicinity of the main nozzle and the liquid level height work together to return the drive head to the horizontal calibration value. The air-fuel mixture concentration is normal, and the power output when the throttle is pressed is the same as when the road is level.

[0075] The control process automatically returns to step 1, restarts the real-time calculation of the additional submerged liquid level displacement to determine whether the limit has been exceeded, and initiates the pressure correction cycle as needed. This achieves closed-loop control of the carburetor throttle after a unilateral limit exceedance, enabling the carburetor to adapt to the vehicle's attitude changes under all operating conditions and ensuring the stability and safety of throttle control under different road conditions.

[0076] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A carburetor throttle control method, characterized in that, include: The additional submerged liquid level displacement is obtained, which is the additional displacement of the liquid level in the vehicle float chamber relative to the top of the main nozzle. When the additional immersion level displacement is 0, the difference between atmospheric pressure and the reference pressure in the vicinity of the main nozzle is marked as the reference drive differential pressure. The reference pressure in the vicinity of the main nozzle is the gas pressure in the cavity space next to the main nozzle and connected to the emulsified air hole when the vehicle is parked horizontally. Obtain the fuel density of the fuel used by the carburetor. When the additional immersion level displacement is greater than 0, multiply the fuel density by the gravitational acceleration and then by the additional immersion level displacement. The product is marked as the additional level head. The additional level head is the pressure increment caused by the additional displacement of the float chamber liquid level when the vehicle goes downhill. When the additional immersion level displacement is greater than 0, the value obtained by adding the real-time main nozzle pressure to the reference drive differential pressure and then subtracting the additional level head is marked as the target float chamber pressure. The real-time main nozzle pressure is the gas pressure in the cavity space connected to the emulsified air hole next to the main nozzle when the vehicle is going downhill. The target float chamber pressure is the target pressure value that the float chamber needs to be adjusted to achieve.

2. The carburetor throttle control method according to claim 1, characterized in that, Also includes: Obtain the area A of the fixed micropores that connect the air cavity above the float chamber to the atmosphere. t Obtain the low-pressure reference zone pressure P S The low-pressure reference zone pressure is the pressure in the area connected to the variable orifice of the air chamber above the float chamber; Based on atmospheric pressure, target float chamber pressure, and fixed micropore area A t The atmospheric refueling flow rate for the float chamber is calculated as follows: ； Q t A is the air supply flow rate from the atmosphere to the float chamber. t To fix the micropore area, P a Atmospheric pressure, P b For the target float chamber pressure, P a -P b For pressure difference; The air supply flow rate from the atmosphere to the float chamber is the flow rate of gas drawn into the float chamber from the atmosphere through fixed micro-holes.

3. The carburetor throttle control method according to claim 2, characterized in that, include: Based on the target float chamber pressure and the low-pressure reference zone pressure P S and variable aperture area A s The discharge flow rate from the float chamber to the low-pressure reference is calculated as follows: ； Q s A is the discharge flow rate from the float chamber to the low-pressure reference. s For the variable aperture area, P b For the target float chamber pressure, P S For the low-pressure reference zone pressure, P b -P s For pressure difference; The discharge flow rate from the float chamber to the low-pressure reference is the flow rate of gas discharged from the float chamber to the low-pressure reference zone through the variable orifice; The variable orifice area A of the adjustable orifice, which connects the air chamber above the float chamber to the low-pressure reference region, is calculated by jointly determining the air supply flow rate from the atmosphere to the float chamber and the discharge flow rate from the float chamber to the low-pressure reference region. s .

4. The carburetor throttle control method according to claim 3, characterized in that, include: The real-time pitch angle is obtained by the vehicle's angle sensor. The real-time pitch angle is the tilt angle of the vehicle in the forward and backward direction. Obtain the relative reference height of the top of the main nozzle. The main nozzle is the main channel through which the emulsified fuel-air mixture is injected into the throat. The relative reference height of the top of the main nozzle is the height of the top of the main nozzle in the carburetor relative to the preset reference surface of the carburetor. Obtain the static liquid level relative reference height, which is the height of the static liquid level of the fuel in the float chamber relative to the preset reference surface when the vehicle is parked horizontally; Obtain the equivalent arm length determined by the float chamber structure. The equivalent arm length is the equivalent displacement scale of the fuel level in the float chamber when the vehicle tilts forward and backward. The product obtained by multiplying the equivalent arm length by the tangent of the real-time pitch angle absolute value is marked as the theoretical displacement, which is the theoretical displacement of the liquid surface caused by the vehicle tilting.

5. A carburetor throttle control method according to claim 4, characterized in that, include: The difference between the relative height of the top of the main nozzle and the relative height of the static liquid level is marked as the horizontal height difference, which is the height difference between the top of the main nozzle and the static liquid level in a horizontal attitude.

6. The carburetor throttle control method according to claim 5, characterized in that, Methods for obtaining additional submerged liquid level displacement include: Subtract the horizontal height difference from the theoretical displacement to obtain a difference value. Then compare this difference value with the value 0. Take the maximum value between this difference value and the value 0. Mark the maximum value as the extra submerged liquid level displacement. The extra submerged liquid level displacement is used to determine whether a unilateral boundary breach has occurred. When the additional submerged liquid level displacement is greater than 0, it is determined that a single-sided cross-boundary has occurred. A single-sided cross-boundary occurs when the vehicle is continuously going downhill, and the float chamber liquid level is submerged relative to the top of the main nozzle due to the unidirectional pitch attitude of the carburetor, which causes air intake to be blocked, resulting in the continuous enrichment of fuel mixture at the same small throttle opening.

7. A carburetor throttle control method according to claim 6, characterized in that, A pressure measuring point is preset in the cavity space next to the main nozzle and connected to the emulsified air hole. A pressure sensor is installed at the preset pressure measuring point. When the additional immersion liquid level displacement is 0, the pressure value read is marked as the reference pressure of the main nozzle neighborhood. When the additional immersion liquid level displacement is greater than 0, the pressure value read is marked as the real-time main nozzle pressure.

8. A carburetor throttle control method according to claim 7, characterized in that, The variable orifice area A is calculated by jointly determining the air supply flow rate from the atmosphere to the float chamber and the discharge flow rate from the float chamber to the low-pressure reference. s ,include: Based on the fact that the air supply flow rate from the atmosphere to the float chamber is equal to the air discharge flow rate from the float chamber to the low-pressure reference, the variable orifice area A can be calculated. s The details are as follows: ； Where A s The area is the variable aperture.

9. A carburetor throttle control method according to claim 8, characterized in that, When the additional immersion liquid level displacement is greater than 0, the opening of the variable orifice connecting the upper chamber of the float chamber to the low-pressure reference zone is adjusted by a stepper motor to the calculated variable orifice area A. s The corresponding geometric area.

10. A carburetor throttle control method according to claim 9, characterized in that, The system receives and monitors the changes in the additional immersion liquid level displacement in real time. If the value of the additional immersion liquid level displacement changes from greater than 0 to 0, it is determined that the unilateral boundary breach has been resolved, and the variable orifice area A is adjusted accordingly. s The variable aperture connecting the upper chamber of the float chamber to the low-pressure reference area is set to 0 and adjusted to 0 via a stepper motor.

Images