System and method for predicting negative pressure of brake booster of vehicle

Abstract

The present invention relates to a system and method for predicting the negative pressure of a brake booster of a vehicle, the system comprising: a driving information detector, which detects driving information about the vehicle; and a controller, which determines the intake manifold negative pressure based on the intake manifold pressure and the atmospheric pressure as driving information; and the controller comprises a booster negative pressure predictor, the booster negative pressure predictor predicts the brake booster negative pressure by integrating the rate of change of the charging rate and the discharge rate according to the negative pressure over time, the rate of change of the charging rate and the discharge rate being determined by using the brake booster negative pressure determined in the previous cycle according to the prediction logic of the brake booster negative pressure, the intake manifold negative pressure of the current cycle and the simulated brake pedal force signal of the simulated vehicle acceleration of the current cycle.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present application claims priority to Korean Patent Application No. 10-2019-0178317 filed on Dec. 30, 2019 and Korean Patent Application No. 10-2020-0050755 filed on Apr. 27, 2020, the entire contents of which are incorporated herein for all purposes by this reference. Technical Field

[0003] The present invention relates to a brake booster negative pressure prediction system and method, and more specifically, to a system and method for predicting the brake booster negative pressure of a vehicle that can improve the cooling performance and braking performance of the vehicle, wherein a brake booster sensor and a brake pedal force sensor are omitted. Background Art

[0004] Generally, when the brake negative pressure stored in the brake booster of the vehicle is insufficient, the brake pedal of the vehicle becomes hard, so that the risk of an accident increases. In order to improve the current problem, in the case of insufficient brake negative pressure, a logic of restoring the brake negative pressure by stopping the operation of various auxiliary devices such as an air conditioner (A / C) is applied.

[0005] The compressor included in the air conditioner affects the engine load of the vehicle because the compressor utilizes the power of the vehicle engine. When the brake negative pressure drops below a certain value, the air conditioner operation is stopped or cut off, thereby ensuring the driving force required for the brake negative pressure.

[0006] The brake negative pressure is the pressure stored in the actual brake booster and the actual measured value measured by the real booster sensor. However, in order to perform the control for stopping the operation of the air conditioner, many manufacturers use the vehicle intake manifold negative pressure to generate the brake booster negative pressure instead of using the real booster sensor due to problems such as increased costs. The intake manifold negative pressure indicates the difference between the atmospheric pressure and the pressure of the intake manifold.

[0007] However, in the case of using the intake manifold negative pressure of the intake manifold, since the intake manifold negative pressure is determined to be small even when sufficient pressure is stored in the brake booster, the operation of the air regulator is frequently stopped.

[0008] When a vehicle without a booster sensor uses the intake manifold negative pressure to increase the reference pressure for controlling the air conditioner to stop operation, there is a problem of reduced cooling performance due to frequent stops of the air conditioner. When the reference pressure is reduced, the air conditioner stops less frequently, but the braking performance deteriorates.

[0009] Therefore, the control for stopping the operation of the air regulator using the intake manifold negative pressure needs to be corrected.

[0010] The information included in this Background of the Invention section is only intended to enhance understanding of the overall background of the invention and should not be taken as an acknowledgment or any form of suggestion that this information constitutes the prior art already known to a person of ordinary skill in the art. Summary of the invention

[0011] Various aspects of the present invention are directed to providing a system and method for predicting a vehicle's brake booster negative pressure, which is configured to improve the vehicle's cooling performance and braking performance through a prediction logic for the brake booster negative pressure, the prediction logic utilizing a simulated brake pedal force signal of a vehicle that does not include a brake booster sensor and a brake pedal force sensor, and a charging rate and a discharging rate of negative pressure generated based on an intake manifold negative pressure.

[0012] An exemplary embodiment of the present invention can provide a system for predicting the negative pressure of a brake booster of a vehicle, the system comprising: a driving information detector configured to detect driving information about the vehicle according to the driving of the vehicle; and a controller connected to the driving information detector, the controller configured to: determine the intake manifold negative pressure based on the pressure of the intake manifold and the atmospheric pressure as driving information; and the controller comprises a booster negative pressure predictor, the booster negative pressure predictor configured to: predict the brake booster negative pressure by integrating the rate of change of the charging rate and the discharge rate according to the brake booster negative pressure over time, the rate of change of the charging rate and the discharge rate being determined by using the brake booster negative pressure determined in the previous cycle according to the prediction logic of the brake booster negative pressure, the intake manifold negative pressure of the current cycle and the simulated brake pedal force signal of the simulated vehicle acceleration of the current cycle.

[0013] The controller may be configured to generate the acceleration inflection point identification signal by intersecting the time-varying simulated brake pedal force signal with a reference line that is a zero crossing.

[0014] The controller may be configured to correct a charging rate and a discharging rate based on the acceleration inflection point identification signal.

[0015] When the predicted brake booster negative pressure is less than or equal to a reference negative pressure for controlling the stopping of the operation of the vehicle air conditioner, the controller may be configured to determine that the predicted brake booster negative pressure is insufficient, thereby stopping the operation of the air conditioner.

[0016] The driving information detector may be configured to detect driving information from at least one of a vehicle speed sensor, a vehicle acceleration sensor, a gear position sensor, an accelerator pedal sensor, a brake pedal operation sensor, a timer, and an atmospheric pressure sensor.

[0017] The booster negative pressure predictor may be configured to collect intake manifold negative pressure and driving information, and generate predicted brake booster negative pressure at a period of a certain time period.

[0018] The booster negative pressure predictor may include: a charging model module, which is configured to use the brake booster negative pressure determined in the previous cycle and the intake manifold negative pressure of the current cycle to determine a first pressure difference that varies with time; a discharge model module, which is configured to use the difference between the brake booster negative pressure determined in the previous cycle and the intake manifold negative pressure of the current cycle as a basic factor, and use a simulated brake pedal force signal to compensate the basic factor to determine a second pressure difference that varies with time; a summation module, which is configured to determine a change rate by adding a discharge rate of the brake booster negative pressure corresponding to the second pressure difference and a charging rate of the brake booster negative pressure corresponding to the first pressure difference; and an integration module, which is configured to integrate the change rate over time and output a predicted brake booster negative pressure.

[0019] The charging rate of the brake booster negative pressure according to the first pressure difference may be output as a positive value, and the discharging rate of the brake booster negative pressure according to the second pressure difference may be output as a negative value.

[0020] The charging model module may be configured to determine the charging rate using a control map that uses the first pressure differential as its input.

[0021] The discharge model module may be configured to determine a multiplication factor for correcting a discharge rate using a correction map using a displacement change amount of a simulated brake pedal force as its input value.

[0022] The discharge model module may be configured to increase the discharge rate by an additional correction amount according to a repetition frequency of zero crossings generated when repeated braking due to an applied state and a released state of a brake operation signal continues to occur.

[0023] The discharge model module may be configured to increase the discharge rate by an additional correction amount when the discharge model module continuously detects that the vehicle acceleration or the vehicle speed has a magnitude greater than or equal to a reference magnitude.

[0024] The integration module may be configured to feed the predicted brake booster negative pressure back to the charging model module and the exhaust model module such that the predicted brake booster negative pressure is used to determine a charging rate and exhaust rate for a next cycle generated after the current cycle.

[0025] The controller may be configured to restart the vehicle in a state where the vehicle is stopped by an idle stop and start (ISG) system when the predicted brake booster negative pressure is less than or equal to a reference negative pressure.

[0026] An exemplary embodiment of the present invention can provide a method for predicting a brake booster negative pressure of a vehicle, the method comprising: a) a controller collects driving information about the vehicle according to the driving of the vehicle, thereby determining a simulated brake pedal force signal and an intake manifold negative pressure, wherein the simulated brake pedal force signal simulates changes in vehicle acceleration; b) the controller determines a first pressure difference that varies with time using the brake booster negative pressure determined in a previous cycle and the intake manifold negative pressure of a current cycle; c) the controller uses the difference between the brake booster negative pressure determined in a previous cycle and the intake manifold negative pressure of a current cycle as a basic factor to determine a second pressure difference that varies with time by compensating the basic factor using a simulated brake pedal force signal; d) the controller determines a change rate by adding a discharge rate of the brake booster negative pressure corresponding to the second pressure difference to a charging rate of the brake booster negative pressure corresponding to the first pressure difference, thereby predicting the brake booster negative pressure by integrating the change rate over time.

[0027] Step a) may include: the controller generates a time-varying simulated brake pedal force signal by filtering the vehicle acceleration change signal in the operating range of the vehicle brake; and the controller generates an acceleration inflection point identification signal by making the simulated brake pedal force signal intersect with a reference line as a zero crossing.

[0028] Step b) may include setting, by the controller, an initial brake booster negative pressure generated when there is no previous cycle to a value smaller than the intake manifold negative pressure.

[0029] Step b) may comprise determining, by the controller, the filling rate using a control map which uses the first pressure difference as its input value.

[0030] Step c) may include: determining, by the controller, a multiplication factor for correcting the discharge rate using a correction map using a displacement variation of the simulated brake pedal force as its input value.

[0031] The method for predicting a brake booster negative pressure of a vehicle may further include: after step d), when the predicted brake booster negative pressure is less than or equal to a reference negative pressure, restarting the vehicle by a controller in a state where the vehicle is stopped by an idle stop and start (ISG) system.

[0032] The system and method for predicting the negative pressure of a brake booster of a vehicle according to an exemplary embodiment of the present invention can implement the prediction logic of the negative pressure of the brake booster, so that the exemplary embodiment of the present invention improves the cooling performance and braking performance of the vehicle without increasing the cost due to adding hardware.

[0033] An exemplary embodiment of the present invention can determine the brake booster negative pressure based on the charging rate and the discharging rate modeled according to the change of the simulated brake pedal force signal that simulates the vehicle acceleration change, so that the exemplary embodiment of the present invention improves the accuracy of the brake booster negative pressure to a level close to the actual measurement value of the brake booster sensor.

[0034] In addition, an exemplary embodiment of the present invention can forcibly reduce the value of the predicted brake booster negative pressure by detecting repeated braking conditions (in which the brake pedal operating force signal continuously changes to be greater than or equal to a reference amplitude and the vehicle acceleration signal continuously changes to be greater than or equal to a reference amplitude), so that an exemplary embodiment of the present invention prevents a malfunction in which the predicted value exceeds the actual measured value.

[0035] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent specific embodiments incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram illustrating the prediction limit of the virtual brake negative pressure.

[0037] Figure 2 A configuration of a system for predicting a brake booster negative pressure of a vehicle according to various exemplary embodiments of the present invention is shown.

[0038] Figure 3 A schematic diagram illustrating a method of simulating a brake pedal force signal according to various exemplary embodiments of the present invention.

[0039] Figure 4 A vehicle acceleration signal processed by simulating a phase of a brake pedal force signal according to various exemplary embodiments of the present invention is shown.

[0040] Figure 5A , Figure 5B , Fig. 6A and Figure 6B A schematic diagram for explaining a method of processing vehicle acceleration according to various exemplary embodiments of the present invention.

[0041] Figure 7is a block diagram illustrating a configuration of a booster negative pressure predictor according to various exemplary embodiments of the present invention.

[0042] Figure 8 A flowchart illustrating a method for predicting a brake booster negative pressure of a vehicle according to various exemplary embodiments of the present invention.

[0043] Fig. 9 It is a diagram illustrating a result of predicting a brake booster negative pressure according to various exemplary embodiments of the present invention.

[0044] It should be understood that the accompanying drawings are not necessarily drawn to scale, but are schematically simplified to present various features to show the basic principles of the present invention. The specific design features disclosed in the present invention (including, for example, specific size, direction, position and shape) will be determined in part by the specific environment to be applied and used.

[0045] In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0046] Reference will be made in detail to various embodiments of the present invention, examples of which are shown in the accompanying drawings and described below. Although the invention will be described in conjunction with the exemplary embodiments, it should be understood that this specification is not intended to limit the invention to those exemplary embodiments. On the other hand, the present invention is intended to cover not only these exemplary embodiments, but also various alternative forms, modifications, equivalent forms and other embodiments that may be included in the spirit and scope of the present invention as defined by the appended claims.

[0047] The following will be more fully described with reference to the accompanying drawings, in which exemplary embodiments of the present application are shown. It will be appreciated by those skilled in the art that various modifications may be made to the described embodiments, all of which will not depart from the spirit or scope of the present invention. Accordingly, the accompanying drawings and description should be considered to be illustrative and non-restrictive in nature. Throughout the specification, the same reference numerals represent the same elements.

[0048] Throughout the specification, unless explicitly described to the contrary, the word "include" and variations such as "comprise" or "comprising" should be understood to imply the inclusion of the elements described, but not the exclusion of any other elements. In addition, the terms "device", "component" and "module" described in the specification mean units for performing at least one function and operation, and can be implemented by hardware components or software components and their combinations.

[0049] Throughout the specification, terms such as "first", "second", "A", "B", etc. may be used to describe various elements, but these elements may not be limited by these terms. These terms are intended to distinguish one element from other elements, but the nature and order or sequence of the elements are not limited by those terms.

[0050] Throughout the specification, unless otherwise specified, brake pedal force (or brake pedal effort) and brake pedal pressure have the same meaning, and pedal means a brake pedal.

[0051] Throughout the specification, a vehicle refers to a vehicle in which a brake booster sensor for measuring a negative pressure of a brake booster and a brake pedal force sensor (or a brake pedal pressure sensor) for measuring a pressure of a brake pedal are not provided.

[0052] A system for predicting a brake booster negative pressure of a vehicle without a brake pedal force sensor (or a device configured to predict a brake booster negative pressure of a vehicle) and a method for predicting a brake booster negative pressure of a vehicle according to various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0053] A method of obtaining a value of a virtual brake booster sensor for solving a problem occurring in a control for stopping an operation of a vehicle air conditioner (A / C) using a vehicle intake manifold negative pressure will be represented as follows.

[0054] The method may obtain a virtual brake booster sensor value by modeling changes in brake booster negative pressure according to vehicle intake manifold negative pressure and vehicle acceleration, such that the method reduces the stopping frequency of the air conditioner.

[0055] However, since this method only uses intake manifold negative pressure and vehicle acceleration as basic factors for predicting brake negative pressure (or brake booster pressure), it is difficult to predict changes in brake negative pressure caused by changes in the vehicle's brake pedal operation mode when the vehicle decelerates at this acceleration.

[0056] Figure 1 A schematic diagram illustrating the prediction limit of the virtual brake negative pressure.

[0057] refer to Figure 1 In order to verify the method of obtaining a virtual brake booster sensor value (or a predicted value of a brake booster sensor), the virtual booster sensor value is compared with an actual booster sensor value according to a change in a brake pedal operation mode of the vehicle. The actual booster sensor value may be a measured value of the brake booster sensor.

[0058] Figure 1Conditions ①, ②, and ③ represent different booster pressure changes according to changes in the brake pedal operation mode when the vehicle is decelerating at a similar acceleration.

[0059] like Figure 1 The condition ① shown in the figure is when the vehicle brake pedal is continuously depressed during a single braking operation. Figure 1 The condition ② shown in ② is a situation where the brake pedal pressure is frequently changed during a single braking operation. Figure 1 Condition ③ shown in ③ is a case where the application (ON) operation and the release (OFF) operation of the brake pedal are repeated. Ideally, the virtual booster sensor value (or predicted value) is close to the actual booster sensor value (or measured value). The degree of approximation is defined as accuracy. In the case of insufficient measured values, the risk situation where the predicted value exceeds the measured value or is opposite to the measured value is defined as a fault. Considering the safety of the vehicle, the accuracy must be high and the fault must not exist or must be 0%.

[0060] In the case of condition ①, the measured value hardly decreases, but the predicted value determined based on the intake manifold negative pressure and acceleration decreases rapidly. Therefore, the accuracy decreases. In the case of condition ②, the measured value and the predicted value are similar. In the case of condition ③, the predicted value exceeds the measured value, resulting in a malfunction.

[0061] In order to solve the above problem, the brake booster negative pressure can be predicted by using the brake pedal force signal of the vehicle that does not include a brake booster sensor and the charging rate and exhaust rate of the negative pressure generated based on the intake manifold negative pressure, so that the prediction accuracy of the brake booster negative pressure is improved. However, the above improved method can only be applied to vehicles that include a brake pedal force sensor that outputs a brake pedal force signal.

[0062] Therefore, the present invention proposes a system and method for predicting brake booster negative pressure, which is applicable to vehicles without a brake booster sensor and a brake pedal force sensor.

[0063] Figure 2 A configuration of a system for predicting a brake booster negative pressure of a vehicle according to various exemplary embodiments of the present invention is shown.

[0064] refer to Figure 2 The system for predicting the brake booster negative pressure of vehicle 1 can be applied to a vehicle in which a brake booster sensor and a brake pedal force sensor are omitted, and the system for predicting the brake booster negative pressure of vehicle 1 may include a controller (e.g., an engine control unit (ECU)) 10, which includes a booster negative pressure predictor 100, a driving information detector 20, and an air conditioning controller 30.

[0065] The controller 10 can determine a virtual brake booster negative pressure according to a prediction logic of the brake booster negative pressure, and can use driving information detected according to the operation of the vehicle to perform control for reducing the stopping frequency of the vehicle's air conditioner (A / C) using the predicted brake booster negative pressure.

[0066] The controller 10 may determine the intake manifold negative pressure by subtracting the pressure of the intake manifold from the atmospheric pressure as driving information. The intake manifold negative pressure may be stored in the brake booster. The controller 10 may obtain a virtual brake booster sensor value by modeling or predicting a change in the brake booster negative pressure according to the intake manifold negative pressure of the vehicle and the acceleration of the vehicle.

[0067] The controller 10 may include a booster negative pressure predictor 100 that predicts a brake booster negative pressure that is close to an actual measured value or a measured value based on a prediction logic of the brake booster negative pressure. The booster negative pressure predictor 100 may predict a current brake booster negative pressure k by integrating the rate of change of the charging rate and the discharge rate over time, the rate of change of the charging rate and the discharge rate being modeled (or determined) using the brake booster negative pressure k-1 determined in the previous cycle according to the prediction logic of the brake booster negative pressure, the intake manifold negative pressure of the current cycle, and the simulated brake pedal force signal of the simulated vehicle acceleration change of the current cycle.

[0068] Because the system for predicting the brake booster negative pressure of the vehicle 1 is applied to a vehicle from which a brake pedal force sensor is omitted, the system may not directly measure the pedal force applied to the vehicle brake pedal by the driver of the vehicle.

[0069] Therefore, a method of indirectly predicting the pedal force is required for a system for predicting the brake booster negative pressure of the vehicle 1 to predict reliable pedal force. The method of indirectly predicting the pedal force can be implemented by a function or software of the controller 10.

[0070] The controller 10 may filter the change of the vehicle acceleration over time, thereby generating an acceleration inflection point identification signal having a tendency similar to the brake pedal force signal measured by the brake pedal force sensor. In an exemplary embodiment of the present invention, since the acceleration inflection point identification signal is similar to the brake pedal force signal measured by the brake pedal force sensor, the acceleration inflection point identification signal may be defined as a simulated brake pedal force signal.

[0071] Figure 3 A schematic diagram illustrating a method of simulating a brake pedal force signal according to various exemplary embodiments of the present invention.

[0072] refer to Figure 3, a vehicle that does not include a brake pedal force signal can filter the vehicle acceleration signal that changes over time to generate an acceleration processing signal such as ②. The acceleration processing signal can approximate the change in the actual brake pedal force of a vehicle such as ①. ① can represent a state where the pedal force changes frequently under a single brake pedal operation. ② can be a simulated brake pedal force signal that simulates the change in the actual brake pedal force.

[0073] When an acceleration processing signal such as ② crosses a predetermined reference line (or zero crossing) of 0, an acceleration inflection point identification signal such as ③ may be generated. Zero crossing may be a reference point (e.g., 0) for determining the change in the acceleration processing signal used when correcting the discharge rate of the brake booster negative pressure during the prediction of the brake booster negative pressure as shown in ④. The zero crossing may have an allowable error of ±0.01. When the acceleration inflection point identification signal is used, the predicted pressure of the brake booster may be additionally reduced.

[0074] The controller 10 may generate a simulated brake pedal force signal, thereby predicting a virtual brake booster negative pressure k as shown in ④ through the booster negative pressure predictor 100 .

[0075] Figure 4 A vehicle acceleration signal processed by simulating a phase of a brake pedal force signal according to various exemplary embodiments of the present invention is shown.

[0076] Figure 5A , Figure 5B , Fig. 6A and Figure 6B A schematic diagram for explaining a method of processing vehicle acceleration according to various exemplary embodiments of the present invention.

[0077] refer to Figures 4 to 6A and Figure 6B , when the driver depresses the brake pedal to operate the brakes of the vehicle while the vehicle is traveling, the acceleration of the vehicle may vary according to the degree of application of the brake pedal force. When the brake pedal force increases, the vehicle acceleration may decrease, and when the brake pedal force decreases, the vehicle acceleration may increase. Therefore, the change in vehicle acceleration and the change in brake pedal force may be correlated with each other.

[0078] like Figure 5A As shown in Figure 4The vehicle acceleration signal shown in may have various frequency combinations depending on the driving state of the vehicle. Since the acceleration signal has a large amount of information including the brake pedal force signal, it is difficult to clearly distinguish the brake pedal force signal from the acceleration signal. In other words, even if the change in vehicle acceleration and the change in brake pedal force are related to each other, the acceleration signal cannot be used as it is because it is difficult to distinguish the brake pedal force signal from the acceleration signal. Therefore, it may be necessary to confirm the process of the change of the acceleration signal similar to the brake pedal force signal.

[0079] The controller 10 can be configured to Fig. 6A Extract the acceleration signal Figure 6B The braking frequency of the acceleration signal can be filtered or shielded, and the specific frequency domain is generated during the driver's braking operation and Figure 5B Shown in.

[0080] Generally, during a braking operation, a high frequency region of the acceleration signal may indicate a strong noise characteristic of the vehicle, and a low frequency region of the acceleration signal may indicate a strong driving characteristic of the vehicle. Therefore, in order to distinguish the brake pedal force signal from the acceleration signal during a braking operation, the controller 10 may set a band filter for a specific frequency domain (i.e., a low frequency region).

[0081] The controller 10 can simulate the brake pedal force signal by filtering the acceleration signal collected during the braking operation to extract only the specific frequency domain of braking. The simulated brake pedal force signal may include most of the signal variation components caused by the braking operation. Figure 4 As shown, an acceleration processing signal simulating the phase of the brake pedal force signal can be obtained.

[0082] As described above, the controller 10 may obtain the acceleration processing signal reflecting the vehicle movement due to the braking operation through a filtering method that extracts the frequency domain of the braking operation from the acceleration signal that varies with time.

[0083] The controller 10 may store various programs and data for driving the booster negative pressure predictor 100 and reducing the stop frequency of the air conditioner using the booster negative pressure predictor in a memory, and may update data generated according to the operation of the controller.

[0084] The controller 10 may store a program of the booster negative pressure predictor 100 in a memory, and may reduce the stop frequency of the air conditioner using the brake booster negative pressure obtained according to the execution of the program.

[0085] The driving information detector 20 can detect driving information about the vehicle measured by various sensors and various controllers according to the driving state of the vehicle. The driving information can be data measured by various sensors and controllers, or it can be information processed from the measured raw data in a format necessary for control.

[0086] For example, the driving information detector 20 can detect driving information from a vehicle speed sensor, a vehicle acceleration sensor, an intake manifold pressure sensor, a gear sensor, an accelerator pedal sensor, a brake pedal sensor (or a brake pedal operation sensor), a height sensor, a slope sensor, a timer or an atmospheric pressure sensor.

[0087] The air conditioning controller 30 can control the overall operation of the air conditioner (A / C), and can perform control for reducing the stop frequency of the air conditioner according to the signal applied by the controller 10. The air conditioner may include a compressor, a condenser, and an evaporator, the compressor compressing the refrigerant, the condenser condensing and liquefying the compressed refrigerant, and the evaporator vaporizing the liquefied refrigerant. The compressor, the condenser, and the evaporator are known elements.

[0088] Figure 7 is a block diagram illustrating a configuration of a booster negative pressure predictor according to various exemplary embodiments of the present invention.

[0089] refer to Figure 7 The booster negative pressure predictor 100 may collect the intake manifold negative pressure and driving information in real time, and may generate the brake booster negative pressure k in a cycle of a predetermined time period.

[0090] The booster negative pressure predictor 100 may include a charging model module 110 that determines a charging rate and a discharging model module 120 that determines a discharging rate. The booster negative pressure predictor 100 may predict the brake booster negative pressure k by integrating a rate of change that is a sum of a charging rate and a discharging rate.

[0091] The booster negative pressure predictor 100 may include a charging model module (or a filling model module) 110 , a discharging model module 120 , a summing module 130 , and an integrating module 140 .

[0092] The charging model module 110 or the discharging model module 120 can receive the brake booster negative pressure k-1 determined in the previous cycle and the driving information of the current cycle, wherein the driving information includes: intake manifold negative pressure, braking operation signal, brake pedal force signal, simulated brake pedal force signal simulating vehicle acceleration change, vehicle speed and vehicle acceleration.

[0093] The charging model module 110 may use the brake booster negative pressure k-1 modeled (or determined) in the previous cycle and the current intake manifold negative pressure to determine a first pressure difference that varies with time. The first pressure difference may be output as a positive value, which is the charging rate (hPa / second) of the booster negative pressure. The charging model module 110 may use a predetermined control map (or a predetermined control lookup table) to determine the charging rate (hPa / second) of the booster negative pressure, the predetermined control map using the first pressure difference as its input value.

[0094] The difference between the current intake manifold negative pressure and the brake booster negative pressure k-1 modeled or output in the previous cycle can be used as the main input factor. The charging model module 110 can determine the charging rate (hPa / sec) by an additional correction factor reflecting the reference driving information.

[0095] The discharge model module 120 can use the difference between the brake booster negative pressure k-1 modeled in the previous cycle and the current intake manifold negative pressure as a base factor, and can use the simulated brake pedal force signal to compensate the base factor to determine a second pressure difference that changes over time. The second pressure difference can be output as a negative value, which is the discharge rate (hPa / second) of the booster negative pressure. The brake pedal force signal can have a compensation value proportional to its change. The discharge model module 120 can use a predetermined correction map to determine the multiplication factor of the discharge rate for correcting the booster negative pressure, and the predetermined correction map uses the displacement change of the simulated brake pedal force as its input value.

[0096] The summing module 130 may determine the rate of change by adding the discharge rate of the second pressure difference determined in the discharge model module 120 and the charge rate of the first pressure difference determined in the charge model module 110 .

[0097] The integration module 140 may integrate the rate of change determined by the summation module 130 over time to output a predicted brake booster negative pressure k.

[0098] The integrator module 140 may feed back or send the predicted brake booster negative pressure to the charging model module 110 and the exhaust model module 120 so that the predicted negative pressure is used to determine the charging rate and exhaust rate for the next cycle.

[0099] When repeated braking continues to occur due to the applied state and released state of the brake operation signal (or brake signal), the discharge model module 120 can reflect or use a predetermined additional correction amount to increase the discharge rate of the booster negative pressure. More specifically, when the discharge model module 120 is based on the following example, Figure 1When repeated braking is detected by continuous operation of the brake pedal as shown in condition ③, the discharge model module 120 can increase the discharge rate to a negative value, thereby forcibly reducing the brake booster negative pressure k. Therefore, malfunction can be prevented.

[0100] The main factor for the forced reduction of negative pressure may be the repetition frequency of zero crossing according to the repeated braking of the brake. The reason for reducing malfunctions by repetition of zero crossing is that when the pedal force is repeatedly generated at a high speed, the repeated braking of the brake is not reflected in the vehicle acceleration due to the inertia of the vehicle. Therefore, by applying a predetermined additional correction amount according to the repetition frequency of zero crossing, the repeated braking of the brake can be reflected in the vehicle acceleration.

[0101] When the discharge model module 120 continuously detects that the vehicle acceleration or vehicle speed has a magnitude greater than or equal to the reference magnitude, the discharge model module 120 can reflect or use a predetermined additional correction amount to increase the discharge rate of the booster negative pressure. The control stability of the brake booster negative pressure k determined according to the change in the brake pedal force can be ensured.

[0102] When the brake booster negative pressure k predicted by the booster negative pressure predictor 100 is less than or equal to the reference negative pressure for controlling the air conditioner to stop operation, the controller 10 may determine that the booster negative pressure is insufficient, thereby stopping the air conditioner operation.

[0103] Based on the configuration of the system for predicting brake booster negative pressure described above, a method for predicting brake booster negative pressure of a vehicle according to various exemplary embodiments of the present invention will be described.

[0104] The controller 10 may be implemented as at least one processor that uses a program to operate the booster negative pressure predictor 100. The program may execute each step of the method for predicting the brake booster negative pressure of a vehicle according to various exemplary embodiments of the present invention.

[0105] Therefore, in the following description of the method for predicting brake booster negative pressure according to various exemplary embodiments of the present invention, the main body or leader of the method can be the controller 10, and the method can use the predicted brake booster negative pressure k to perform control for reducing the air conditioner stop frequency.

[0106] Figure 8 A flowchart illustrating a method for predicting a brake booster negative pressure of a vehicle according to various exemplary embodiments of the present invention.

[0107] refer to Figure 8, the controller 10 of the system for predicting the negative pressure of the brake booster of the vehicle 1 may continuously collect driving information about the vehicle from the driving information detector 20 after the vehicle is started (steps S1 and S2). Depending on the operation (or driving) of the vehicle, the driving information may include at least one of atmospheric pressure, vehicle speed, vehicle acceleration, accelerator pedal operation signal, brake operation signal, altitude, slope, and time.

[0108] The controller 10 may generate a simulated brake pedal force signal (step S3), wherein the simulated brake pedal force signal simulates the change in vehicle acceleration over time in the operating range of the brake. The controller 10 may generate a simulated brake pedal force signal that changes over time by filtering the acceleration change signal of the vehicle. The controller 10 may generate an acceleration inflection point identification signal by making the acceleration processing signal intersect a predetermined reference line (or zero crossing) of 0.

[0109] The controller 10 may determine the intake manifold negative pressure by subtracting the pressure of the intake manifold from the atmospheric pressure as the driving information (step S4 ).

[0110] The controller 10 may operate the timer so that the controller starts to determine the brake booster negative pressure k (step S5) using the driving information, the simulated brake pedal force signal, the intake manifold negative pressure collected in the current cycle, and the brake booster negative pressure k-1 determined in the previous cycle. The controller 10 may set the initial brake booster negative pressure generated when there is no previous cycle to a value less than the intake manifold negative pressure.

[0111] The controller 10 may determine a first pressure difference varying with time using the brake booster negative pressure k-1 determined in the previous cycle and the current intake manifold negative pressure, thereby determining a charging rate of the booster negative pressure (step S6).

[0112] The controller 10 may use the difference between the brake booster negative pressure k-1 determined in the previous cycle and the current intake manifold negative pressure as a base factor, and may use the simulated brake pedal force signal to compensate the base factor, thereby determining a second pressure difference that varies with time, so that the controller determines the discharge rate of the booster negative pressure (step S7). The controller 10 may use a correction map to determine a multiplication factor for correcting the discharge rate of the booster negative pressure, and the correction map uses the displacement change of the simulated brake pedal force as an input value.

[0113] The controller 10 may determine the rate of change by adding the discharge rate of the second pressure difference to the charge rate of the first pressure difference (step S8 ).

[0114] The controller 10 may integrate the determined rate of change over time to generate a predicted brake booster negative pressure k (step S9). The controller 10 may store the predicted brake booster negative pressure in a memory so that the predicted negative pressure is used to determine the charging rate and the exhaust rate of the next cycle.

[0115] When the predicted brake booster negative pressure k is less than or equal to the reference negative pressure for stopping the air conditioner operation ("Yes" in step S10), the controller 10 may determine that the booster negative pressure is insufficient, thereby stopping the air conditioner operation (step S11).

[0116] After step S11 , the controller 10 may return to step S5 and may determine the brake booster negative pressure of the next cycle until the start of the vehicle is stopped.

[0117] When the predicted brake booster negative pressure k exceeds the reference negative pressure for stopping the air conditioner operation ("No" in step S10), the controller 10 may determine that the booster negative pressure is sufficient so as not to stop the air conditioner operation and may execute step S5.

[0118] Fig. 9 It is a diagram illustrating a result of predicting a brake booster negative pressure according to various exemplary embodiments of the present invention.

[0119] Fig. 9 Control results using the system for predicting brake booster negative pressure according to various exemplary embodiments of the present invention are shown.

[0120] As reference Figure 1 As described above, when only the intake manifold negative pressure and the vehicle acceleration are used as basic factors for booster negative pressure prediction, there is a problem that the predicted value is not close to the measured value, resulting in a decrease in accuracy or a malfunction.

[0121] Therefore, the exemplary embodiment of the present invention can output a brake booster negative pressure prediction value that is close to the brake booster negative pressure measurement value using the charging rate and the exhausting rate generated based on the simulated brake pedal force, and can improve the accuracy to 90% or more.

[0122] As described above, the exemplary embodiment of the present invention can implement the prediction logic of the brake booster negative pressure, so that the exemplary embodiment of the present invention improves the cooling performance and braking performance of the vehicle without increasing the cost due to the addition of hardware.

[0123] An exemplary embodiment of the present invention can determine the brake booster negative pressure based on the charging rate and the discharging rate modeled according to the change of the simulated brake pedal force signal that simulates the vehicle acceleration change, so that the exemplary embodiment of the present invention improves the accuracy of the brake booster negative pressure to a level close to the level of the brake booster sensor measurement value.

[0124] In addition, an exemplary embodiment of the present invention can forcibly reduce the predicted value of the brake booster negative pressure by detecting a repeated braking situation (wherein the brake pedal operating force signal continuously changes to be greater than or equal to a reference amplitude and the vehicle acceleration signal continuously changes to be greater than or equal to a reference amplitude), so that an exemplary embodiment of the present invention prevents the fault from reaching 0%.

[0125] The exemplary embodiments of the present invention have been described, but the present invention is not limited to the above-mentioned exemplary embodiments of the present invention, and various other modifications can be made.

[0126] For example, in the above exemplary embodiment of the present invention, it has been described that the controller 10 performs the control for reducing the air conditioner stop frequency using the brake booster negative pressure predicted by the booster negative pressure predictor 100 .

[0127] However, the exemplary embodiment of the present invention is not limited thereto, and the booster negative pressure predictor 100 may include a function of a brake booster sensor of an existing vehicle.

[0128] Generally, after the vehicle is stopped by an Idle Stop and Go (ISG) system, when the pressure of the brake booster becomes insufficient, the vehicle including the ISG system restarts the vehicle using a brake booster sensor. Therefore, when the brake booster sensor is omitted in the vehicle including the ISG system, the vehicle can perform ISG control using the system for predicting the negative pressure of the brake booster of the vehicle 1 according to various exemplary embodiments of the present invention.

[0129] For example, when the predicted brake booster negative pressure of step S9 is less than or equal to the reference negative pressure of ISG control, the controller 10 can restart the vehicle, and when the predicted brake booster negative pressure exceeds the reference negative pressure, the controller can maintain the start-stop state of the vehicle.

[0130] The exemplary embodiments of the present invention are not only implemented by the above-mentioned devices or methods, but can also be implemented by a program for operating functions corresponding to the configuration of the exemplary embodiments of the present invention, a recording medium recording the program, etc., and those skilled in the art can easily implement the implementation according to the description of the above-mentioned exemplary embodiments.

[0131] In addition, terms such as "controller", "control unit", "control device" or "control module" regarding a control device represent a hardware device including a memory and a processor, the processor being configured to execute one or more steps interpreted as an algorithmic structure. The memory stores the algorithmic steps, and the processor executes the algorithmic steps to perform one or more processes of the method according to each exemplary embodiment of the present invention. The controller according to the exemplary embodiment of the present invention can be implemented by a non-volatile memory and a processor, the non-volatile memory being configured to store an algorithm for controlling the operation of each component of the vehicle or data about software instructions for executing the algorithm, and the processor being configured to perform the above-mentioned operations using data stored in the memory. The memory and the processor may be separate chips. Alternatively, the memory and the processor may be integrated in a single chip. The processor may be implemented as one or more processors.

[0132] The control device may be at least one microprocessor operated by a predetermined program, and the predetermined program may include a series of instructions for executing the methods included in the aforementioned various exemplary embodiments of the present invention.

[0133] The aforementioned invention may also be implemented as computer-readable codes on a computer-readable recording medium. A computer-readable recording medium is any data storage device that can store data that can be subsequently read by a computer system. Examples of computer-readable recording media include hard disk drives (HDDs), solid-state disks (SSDs), silicon disk drives (SDDs), read-only memories (ROMs), random access memories (RAMs), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, etc., and are implemented as carrier waves (e.g., transmitted over the Internet).

[0134] In an exemplary embodiment of the present invention, each of the above operations may be performed by a controller, and the controller may be configured by a plurality of controllers or an integrated single controller.

[0135] For convenience of explanation and precise definition of the appended claims, the terms "upper", "lower", "inner", "outer", "above", "below", "upward", "downward", "front", "back", "back", "inner", "outer", "inwardly", "outwardly", "inner", "external", "inner", "external", "forward", "backward" are used to describe features of the exemplary embodiments with reference to the positions of such features as shown in the accompanying drawings. It should be further understood that the term "connect" or its derivatives refer to both direct and indirect connections.

[0136] The foregoing description of the specific exemplary embodiments of the present invention is presented for the purpose of illustration and description. The foregoing description is not intended to be exhaustive, nor is it intended to limit the present invention to the precise form disclosed, and it is apparent that many changes and variations are possible in accordance with the above teachings. The exemplary embodiments are selected and described in order to explain the specific principles of the present invention and its practical application, so that other technical personnel in the art can realize and utilize the various exemplary embodiments of the present invention and its different alternative forms and modified forms. The scope of the present invention is intended to be limited by the appended claims and their equivalents.

Claims

1. A system for predicting negative pressure of a brake booster of a vehicle, the system comprising: a driving information detector configured to detect driving information about the vehicle based on the driving of the vehicle; as well as a controller coupled to the driving information detector and configured to determine an intake manifold negative pressure based on a pressure of the intake manifold and an atmospheric pressure as driving information; Wherein, the controller includes a booster negative pressure predictor, and the booster negative pressure predictor is configured to predict the brake booster negative pressure by integrating the rate of change of the charging rate and the discharge rate of the brake booster negative pressure over time, and the rate of change of the charging rate and the discharge rate is determined by using the brake booster negative pressure determined in the previous cycle according to the prediction logic of the brake booster negative pressure, the intake manifold negative pressure of the current cycle and the simulated brake pedal force signal of the simulated vehicle acceleration of the current cycle.

2. The system for predicting negative pressure of a brake booster of a vehicle according to claim 1, wherein: The controller is configured to generate an acceleration inflection point identification signal by intersecting a simulated brake pedal force signal that varies with time with a reference line that is a zero crossing.

3. The system for predicting negative pressure of a brake booster of a vehicle according to claim 2, wherein: The controller is configured to correct a charging rate and a discharging rate according to the acceleration inflection point identification signal.

4. The system for predicting negative pressure of a brake booster of a vehicle according to claim 1, wherein: When the predicted brake booster negative pressure is less than or equal to a reference negative pressure for controlling the stopping of the operation of the vehicle air conditioner, the controller is configured to determine that the predicted brake booster negative pressure is insufficient, thereby stopping the operation of the air conditioner.

5. The system for predicting negative pressure of a brake booster of a vehicle according to claim 1, wherein: The travel information detector is configured to detect travel information from at least one of a vehicle speed sensor, a vehicle acceleration sensor, a gear position sensor, an accelerator pedal sensor, a brake pedal operation sensor, a timer, and an atmospheric pressure sensor.

6. The system for predicting negative pressure of a brake booster of a vehicle according to claim 1, wherein: The booster negative pressure predictor is configured to collect intake manifold negative pressure and driving information, and generate predicted brake booster negative pressure at a period of a certain time period.

7. The system for predicting negative pressure of a brake booster of a vehicle according to claim 1, wherein: The booster negative pressure predictor comprises: a charging model module configured to determine a first pressure difference varying with time using a brake booster negative pressure determined in a previous cycle and an intake manifold negative pressure in a current cycle; a discharge model module configured to use a difference between a brake booster negative pressure determined in a previous cycle and an intake manifold negative pressure in a current cycle as a base factor and compensate the base factor using a simulated brake pedal force signal to determine a second pressure difference that varies with time; a summing module configured to determine a rate of change by adding a discharge rate of the brake booster negative pressure corresponding to the second pressure difference to a charge rate of the brake booster negative pressure corresponding to the first pressure difference; and An integration module is configured to integrate the rate of change over time and output a predicted brake booster negative pressure.

8. The system for predicting negative pressure of a brake booster of a vehicle according to claim 7, wherein: The charging rate of the brake booster negative pressure according to the first pressure difference is output as a positive value, and the discharging rate of the brake booster negative pressure according to the second pressure difference is output as a negative value.

9. The system for predicting negative pressure of a brake booster of a vehicle according to claim 7, wherein: The charging model module is configured to determine a charging rate using a control map that uses a first pressure difference as an input.

10. The system for predicting negative pressure of a brake booster of a vehicle according to claim 7, wherein: The discharge model module is configured to determine a multiplication factor for correcting a discharge rate using a correction map using a displacement change amount of a simulated brake pedal force as its input value.

11. The system for predicting negative pressure of a brake booster of a vehicle according to claim 10, wherein: The discharge model module is configured to increase the discharge rate by an additional correction amount according to a repetition frequency of zero crossings generated when it is determined that repeated braking due to an applied state and a released state of a brake operation signal continues to occur.

12. The system for predicting negative pressure of a brake booster of a vehicle according to claim 11, wherein: The discharge model module is configured to increase the discharge rate by an additional correction amount when it is determined that the discharge model module continuously detects that the vehicle acceleration or the vehicle speed has a magnitude greater than or equal to the reference magnitude.

13. The system for predicting negative pressure of a brake booster of a vehicle according to claim 7, wherein: The integration module is configured to feed back the predicted brake booster negative pressure to the charging model module and the exhaust model module so that the predicted brake booster negative pressure is used to determine a charging rate and exhaust rate for a next cycle generated after the current cycle.

14. The system for predicting negative pressure of a brake booster of a vehicle according to claim 1, wherein: The controller is configured to restart the vehicle in a state where the vehicle is stopped by the idle stop and start system when it is determined that the predicted brake booster negative pressure is less than or equal to the reference negative pressure.

15. A method for predicting negative pressure of a brake booster of a vehicle, the method comprising: a) collecting driving information about the vehicle according to the driving of the vehicle by a controller, thereby determining a simulated brake pedal force signal and an intake manifold negative pressure, wherein the simulated brake pedal force signal simulates a change in vehicle acceleration; b) determining, by the controller, a first pressure difference varying with time using a brake booster negative pressure determined in a previous cycle and an intake manifold negative pressure in a current cycle; c) using, by the controller, a difference between the brake booster negative pressure determined in a previous cycle and the intake manifold negative pressure in a current cycle as a base factor to determine a second pressure difference that varies with time by compensating the base factor with a simulated brake pedal force signal; d) The controller determines a change rate by adding a discharge rate of the brake booster negative pressure corresponding to the second pressure difference to a charge rate of the brake booster negative pressure corresponding to the first pressure difference, thereby predicting the brake booster negative pressure by integrating the change rate over time.

16. The method according to claim 15, wherein: Step a) comprises: The controller generates a simulated brake pedal force signal that varies with time by filtering a vehicle acceleration variation signal in an operation interval of the vehicle brake; The acceleration inflection point identification signal is generated by the controller by causing the simulated brake pedal force signal to intersect a reference line that is a zero crossing.

17. The method according to claim 15, wherein: Step b) comprises: An initial brake booster negative pressure generated when it is determined that there is no previous cycle is set by the controller to a value smaller than the intake manifold negative pressure.

18. The method according to claim 15, wherein: Step b) comprises: The charge rate is determined by the controller using a control map that uses the first pressure differential as its input.

19. The method according to claim 15, wherein: Step c) comprises: The multiplication factor for correcting the discharge rate is determined by the controller using a correction map that uses the displacement variation of the simulated brake pedal force as its input value.

20. The method of claim 15, further comprising: After step d), when it is determined that the predicted brake booster negative pressure is less than or equal to the reference negative pressure, the vehicle is restarted by the controller in a state where the vehicle is stopped by the idle stop and start system.

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