Testing Method and Application of a Hydraulic Vacuum Boost Assisted Braking System

Abstract

The present invention discloses a test method for a hydraulic vacuum assisted braking system and its application. The steps of the test method specifically include: preheating the vehicle, adjusting the vacuum pressure regulating valve, simulating a low vacuum condition, gently stepping on the brake or quickly stepping on the brake, adjusting the vacuum pressure regulating valve again, adjusting the vehicle vacuum state, and finally performing data processing and result evaluation. The present invention is an evaluation method based on real vehicle road tests, which can truly reflect the usage of the hydraulic vacuum assisted braking system, verify and evaluate the functions of the hydraulic vacuum assisted braking system through objective measurement and result evaluation, and can objectively and truly evaluate the effects in aspects such as reducing the driver's braking force, increasing the deceleration, protecting the safety of the driver and passengers, and improving the driving quality of the vehicle.

Description

Technical Field

[0001] The present invention relates to a test method for an auxiliary brake system and application thereof, and in particular to a test method for a hydraulic vacuum booster brake system and application thereof. Background Art

[0002] With the development of the automotive industry, people's demands for vehicle performance are becoming increasingly stringent, particularly for high-performance and comfortable braking systems. Braking performance is also a crucial aspect of vehicle performance, crucial to the safety of drivers and passengers. Improving the performance of vehicle braking systems is a crucial task for production and design departments. Currently, the most common braking system is a vacuum-assisted hydraulic brake system, of which the vacuum booster is a key component.

[0003] The vacuum booster is divided into two chambers, one for the atmosphere and the other for the vacuum. During braking, the pressure difference between the two chambers is used to push the diaphragm in the middle to achieve the assist function. Therefore, the atmospheric pressure and the vacuum degree in the vacuum chamber are the fundamental factors affecting the assist performance. The atmospheric pressure gradually decreases with increasing altitude. The vacuum in the vacuum chamber is provided by the engine intake pipe. When the vehicle is cold-started, braked continuously, braked with high intensity, or driven in plateau areas, the assist capability is often significantly reduced due to the low pressure difference between the two sides. This problem is particularly prominent at this stage when supercharged engines are widely used. When the deceleration at the maximum assist point of the vacuum booster is lower than 0.6g, it is necessary to increase the vacuum degree with the help of an electronic vacuum pump or to increase the brake line pressure through the hydraulic vacuum booster auxiliary braking system in the ESP system to improve the vehicle's braking performance.

[0004] With the gradual development and improvement of ESP functionality, hydraulic vacuum assisted braking systems have become widely adopted as an additional feature of ESP in new models, gradually replacing the electronic vacuum pump's assistance function under low-vacuum conditions. The hydraulic vacuum assisted braking system monitors the vacuum level within the vacuum booster, brake line pressure, and vehicle deceleration in real time. When the vacuum booster reaches maximum assist capability, ESP's active boost function increases brake line pressure according to a calibrated boost curve, reducing the driver's braking force and increasing vehicle deceleration. The hydraulic vacuum assisted braking system plays a vital role in protecting driver and passenger safety and improving vehicle driving quality.

[0005] Hydraulic vacuum assisted braking systems are often calibrated by ESP suppliers. Different suppliers have different calibration capabilities, and their performance on different vehicle models also varies. For vehicle manufacturers, it is necessary to conduct performance tests on competing vehicles to provide design targets for product development, verify the performance of newly developed products, evaluate their functions and performance, and put forward improvement suggestions to enhance the driving quality of products. Currently, such tests have not been carried out in the industry, and there is a lack of clear test conditions and methods, which can no longer meet people's requirements and urgent improvements are needed. Summary of the Invention

[0006] The purpose of the present invention is to provide a test method and its application for a hydraulic vacuum assisted braking system, clarify the test conditions and working conditions, provide a reference for the optimization of the hydraulic vacuum assisted braking system, and solve the deficiencies existing in the prior art.

[0007] The present invention provides the following solutions:

[0008] A test method for a hydraulic vacuum assisted braking system specifically includes:

[0009] Vehicle preheating: During the process of the vehicle driving at a constant speed, perform braking to stop and accelerate at intervals, and check whether the vehicle reaches the normal operating temperature after preheating ends;

[0010] Adjust the vacuum pressure regulating valve to simulate low vacuum conditions: Gradually increase the vacuum pressure value starting from 0 kPa until the hydraulic vacuum assisted braking system is no longer activated;

[0011] Slowly step on the brake: Slowly step on the brake pedal and gradually increase the pedal travel until the anti-lock braking system (ABS) starts to work or a certain wheel locks up, and record various data during the test process;

[0012] Quickly step on the brake: Quickly step on the brake pedal, quickly step on the brake pedal to a certain position and keep it unchanged until the vehicle stops, and record various data during the test process;

[0013] Adjust the vacuum pressure regulating valve again to adjust the vehicle vacuum state;

[0014] Data processing: Use the color contour map of the auto power spectral density tracking time to analyze the vibration amount of the brake pedal and the noise near the driver's ear, calculate the average braking deceleration, and correct the braking distance;

[0015] Result evaluation: Evaluate whether the boost timing, boost effect, pressure build-up gradient, and braking efficiency of the hydraulic vacuum assisted braking system during braking under the condition of turning on the hydraulic vacuum assisted braking are appropriate, and whether the boost noise and pedal vibration are obvious.

[0016] Further, the vehicle preheating specifically includes: Vehicle preheating: The vehicle travels at a constant speed of 70 km / h, brakes and stops every 2.5 km of travel, for a total of 4 times. After stopping, it accelerates to 70 km / h and travels at a constant speed, and then performs the next braking. After the preheating is completed, the vehicle should reach the normal operating temperature, and the brake temperature should be maintained between 80°C and 100°C, and the brake temperature should be maintained within this temperature range before each braking starts.

[0017] Further, the gentle braking specifically includes: Adjust the vacuum regulator valve to simulate a low vacuum condition. Starting from 0 kPa, gradually adjust the vacuum degree in increments of 10 kPa until the hydraulic vacuum assist braking system is no longer activated. Slowly step on the brake pedal until the anti-lock braking system ABS starts to work or a certain wheel locks up.

[0018] Further, the slowly stepping on the brake pedal is specifically: The pedal stroke increases at a rate of 25 mm / s or the pedal force increases in increments of 50 N / s to 100 N / s until the anti-lock braking system ABS starts to work or a certain wheel locks up.

[0019] Further, the hard braking specifically includes: Adjust the vacuum regulator valve to simulate a low vacuum condition. Starting from 0 kPa, gradually adjust the vacuum degree in increments of 10 kPa until the hydraulic vacuum assist braking system is no longer activated. Quickly step on the brake pedal, step on the brake pedal to a certain position and keep it unchanged until the vehicle stops.

[0020] Further, the quickly stepping on the brake pedal is specifically: The pedal stroke steps on the brake pedal to a certain position at a speed not lower than 250 mm / s and keeps it unchanged until the vehicle stops. The average pedal force applied is 500 N or reaches the ABS full cycle adjustment.

[0021] Further, the data processing specifically includes: Analyzing the brake pedal vibration and the driver's ear side noise using a color contour map of the auto power spectral density tracking time;

[0022] Calculate the average braking deceleration according to a = v 2 / (25.92×s), where v is the vehicle speed when actuating the brake pedal, and s is the distance traveled from actuating the brake pedal to the vehicle stopping;

[0023] The braking distance is corrected according to s X =s×(v 2 G / v 2 ) where v G is the specified initial vehicle speed, v is the vehicle speed when actuating the brake pedal, and s is the distance traveled from actuating the brake pedal to the vehicle stopping.

[0024] Further, the result evaluation specifically includes:

[0025] Evaluating whether the boost timing, boost effect, pressure build-up gradient, braking efficiency are appropriate during braking under the condition of activating the hydraulic vacuum boost assisted braking, and whether the supercharging noise and pedal vibration are obvious;

[0026] Comparing the differences in pipeline pressure, average braking deceleration and braking distance correction value between the working conditions of activating and deactivating the hydraulic vacuum boost assisted braking system under the same vacuum degree condition;

[0027] The specific condition of comparing the same vacuum degree is: starting from 0 kPa, the vacuum degree is gradually increased in increments of 10 kPa;

[0028] Drawing a comparison chart of test curves for activating and deactivating the hydraulic vacuum boost assisted braking system.

[0029] Further, during the test process, record the vacuum degree, vehicle speed, distance, pedal force, braking deceleration, pipeline pressure, braking pedal vibration amount and driver's ear-side noise. Each test is repeated twice for each vacuum degree, and the tests are carried out separately in two states of activating and deactivating the hydraulic vacuum boost assisted braking system, and compare the differences in braking pedal characteristics between the two states.

[0030] The application of a test method for a hydraulic vacuum boost assisted braking system in vehicle testing.

[0031] The present invention has the following advantages compared with the prior art:

[0032] The present invention is an evaluation method based on real vehicle road tests, which can truly reflect the usage of the hydraulic vacuum boost assisted braking system. By objective measurement and result evaluation, it verifies and evaluates the functions of the hydraulic vacuum boost assisted braking system, and can objectively and truly evaluate the effects of reducing the driver's braking force, increasing the deceleration, protecting the safety of the driver and passengers, and improving the driving quality of the vehicle, etc.

[0033] Through the summary of test experiences in multiple projects, when implementing the test method and its application, the present invention adopts different technical means such as gradually adjusting the vacuum degree in increments of 10 kPa starting from 0 kPa, slowly stepping on the braking pedal, quickly stepping on the braking pedal, activating and deactivating the hydraulic vacuum boost assisted braking system under the same vacuum degree condition, etc., to simulate the complex working conditions of the vehicle in multiple dimensions and aspects, covering the slow braking and emergency braking conditions under different vacuum degree conditions, and comprehensively covering all objective factors and subjective factors that affect the braking effect as much as possible.

[0034] Under the conditions of gentle braking or emergency braking, it is necessary to compare the performance differences between the hydraulic vacuum assist braking system being turned on and off under the same vacuum degree conditions, and analyze the differences in performance between the two states; through the test method and its application of the present invention, it is possible to show and analyze whether the assist timing, assist effect, pressure build-up gradient, braking efficiency, etc. are appropriate during the braking process, and whether the supercharging noise and pedal vibration are obvious.

[0035] Through testing and evaluating the hydraulic vacuum assist braking systems of various ESP products and various vehicle models, and simulating the actual usage conditions of users, the present invention summarizes a set of detailed test methods for hydraulic vacuum assist braking systems, filling the gap in the test methods in this field for vehicle manufacturers. Brief Description of the Drawings

[0036] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 It is the working principle effect diagram of the hydraulic vacuum assist braking system.

[0038] Figure 2 It is the flow chart of the test method of the hydraulic vacuum assist braking system of the present invention.

[0039] Figure 3 It is the columnar comparison chart of the average braking deceleration under the same vacuum degree conditions.

[0040] Figure 4 It is the columnar comparison chart of the front brake line pressure under the same vacuum degree conditions.

[0041] Figure 5 It is the columnar comparison chart of the braking distance under the same vacuum degree conditions.

[0042] Figure 6 It is the comparison chart of the pedal force and deceleration with and without hydraulic braking assist under the experimental condition of a vacuum degree of 0 kPa.

[0043] Figure 7 It is the comparison chart of the pedal force and line pressure values with and without hydraulic braking assist under the experimental condition of a vacuum degree of 0 kPa.

[0044] Figure 8 It is the comparison chart of the pedal force and deceleration with and without hydraulic braking assist under the experimental condition of a vacuum degree of 10 kPa.

[0045] Figure 9 It is a comparison chart of pedal force and pipeline pressure values with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 10 kPa.

[0046] Figure 10 It is a comparison chart of pedal force and deceleration with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 20 kPa.

[0047] Figure 11 It is a comparison chart of pedal force and pipeline pressure values with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 20 kPa.

[0048] Figure 12 It is a comparison chart of pedal force and deceleration with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 30 kPa. [[ID=…]]

[0049] Figure 13 It is a comparison chart of pedal force and pipeline pressure values with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 30 kPa.

[0050] Figure 14 It is a comparison chart of pedal force and deceleration with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 40 kPa.

[0051] Figure 15 It is a comparison chart of pedal force and pipeline pressure values with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 40 kPa.

[0052] Figure 16 It is a comparison chart of pedal force and deceleration with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 50 kPa.

[0053] Figure 17 It is a comparison chart of pedal force and pipeline pressure values with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 50 kPa.

[0054] Figure 18 It is a comparison chart of pedal force and deceleration with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 60 kPa.

[0055] Figure 19 It is a comparison chart of pedal force and pipeline pressure values with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 60 kPa.

[0056] Figure 20 It is a comparison chart of pedal force and deceleration with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 70 kPa.

[0057] Figure 21It is a comparison chart of pedal force and pipeline pressure values with and without hydraulic braking assistance under the experimental condition of a vacuum degree of 70 kPa.

[0058] Figure 22 It is a comparison chart of pedal force and deceleration with and without hydraulic braking assistance under the experimental condition of the maximum vacuum degree.

[0059] Figure 23 It is a comparison chart of pedal force and pipeline pressure values with and without hydraulic braking assistance under the experimental condition of the maximum vacuum degree. Specific implementation manners

[0060] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0061] As Figure 1 shown, the hydraulic vacuum assist braking system is a value-added safety function in ESP, which is used to assist the hydraulic braking system with a vacuum booster to ensure that the input of the driver's braking pedal force is enhanced and amplified when the booster assistance is insufficient. The specific functions are as follows:

[0062] a) Compensate for the low maximum boost point of the booster due to limited booster size or limited vacuum degree;

[0063] b) Use active supercharging to amplify the braking force input by the driver; [[ID=2,6]]

[0064] c) Compensate for the insufficient vacuum degree when the vehicle is cold-started, continuously braked, strongly braked or traveling in high-altitude areas;

[0065] d) Assist the driver to brake in the case of complete loss of vacuum assist (booster failure) to meet the requirements of regulations (GB21670, ECE R13H, FMVSS 135), that is, when the driver brakes with a braking force of 500 N, the deceleration reached by the vehicle is greater than 2.44 m / s 2 ;

[0066] e) Provide hydraulic increase smoothly, with as low noise and braking pedal vibration as possible, making it difficult for users to notice;

[0067] f) The hydraulic vacuum assist braking system monitors the vacuum degree in the vacuum booster, the brake line pressure, and the vehicle deceleration in real time. When the vacuum booster approaches its maximum boosting capacity, it uses the active boosting function of the ESP to boost the brake line pressure according to the calibrated boosting curve, so as to reduce the driver's braking force and increase the vehicle deceleration.

[0068] Combined with Figure 1 the relationship diagram of the brake pedal force and the brake line pressure, it can be seen that the hydraulic vacuum assist braking system plays an important role in protecting the safety of the driver and passengers and improving the driving quality of the vehicle.

[0069] The present invention discloses multiple embodiments, and the following various embodiments all meet the following test conditions and sensor installation requirements:

[0070] Test conditions:

[0071] Test mass: The test mass is the maximum designed total mass of the whole vehicle, including the mass of the test personnel, test instruments and equipment. The insufficient part is replaced by load objects. The axle load distribution should be as close as possible to the technical requirements of the manufacturer, or other load states can also be selected according to actual needs.

[0072] Tires: Before the test, the tire pressure is inflated to the factory-specified pressure in the cold state, with an error not exceeding ±10 kPa, and the remaining depth of the tire tread is not less than 50% of the new tire.

[0073] Test site and meteorological conditions: The test road surface is a dry and flat asphalt or concrete paved road surface with good adhesion performance. The longitudinal slope of any 50 m length of the road is less than 1%, and the camber slope is less than 2%. The meteorological conditions require no rain, snow, fog, or haze, the atmospheric temperature is 0°C to 40°C, and the wind speed is less than 5 m / s.

[0074] Test instruments and equipment: Data acquisition system, vehicle speed measurement device, deceleration measurement device, pedal force measurement device, pipeline pressure sensor, air pressure sensor, vibration acceleration sensor, miniature microphone sensor, temperature sensor, mass measurement device, tire pressure gauge, vacuum pressure regulating valve, etc.

[0075] Sensor installation requirements:

[0076] Air pressure sensor: Measures the air pressure in the vacuum booster, converts the vacuum degree in the vacuum booster according to the local atmospheric pressure, is arranged at the air inlet of the vacuum booster, and is connected in series in the original vacuum pipeline;

[0077] Vacuum pressure regulating valve: Used to adjust the vacuum degree in the vacuum booster, and is installed in series in the vacuum pipeline;

[0078] Pipeline pressure sensor: Measures the brake line pressure, is arranged near the front wheel cylinder, and is connected in series at the connection of the hard and soft brake pipelines;

[0079] Pedal force measuring device: Measures the braking pedal force and is installed on the braking pedal;

[0080] Deceleration measuring device: Measures the vehicle deceleration and is installed at the vehicle's center of mass position or acquires the longitudinal acceleration of the vehicle's CAN bus as a substitute;

[0081] Vehicle speed measuring device: Measures the actual vehicle speed and can select GPS, non-contact speedometer or acquire the vehicle speed of the vehicle's CAN bus as a substitute;

[0082] Miniature microphone sensor: Measures the noise beside the driver's right ear. The direction of the maximum sensitivity of the miniature microphone sensor should be consistent with the driver's line of sight (usually the vehicle driving direction). The distance between the sensor and the vehicle compartment wall or seat cushion must be greater than 0.15 m. The vertical position is (0.7 ± 0.05) m above the seat surface when there is no one, and the horizontal position is (0.2 ± 0.02) m behind the vertical plane where the front and rear center line of the seat surface is located;

[0083] Vibration acceleration sensor: The vibration acceleration sensor should be installed on the acting surface of the braking pedal. The Z-axis of the sensor is perpendicular to the acting surface of the braking pedal, and the X-axis of the sensor is in the same plane as the vehicle's X-axis;

[0084] Data acquisition instrument: Acquires the measurement results of the above sensors and vehicle speed signals, throttle pedal opening signals, brake switch signals, vacuum degree signals, master cylinder pressure signals, vehicle longitudinal acceleration signals, hydraulic vacuum assist braking system working state signals, etc. in the vehicle's CAN bus for subsequent data processing and analysis.

[0085] Such as Figure 2 Shown in Embodiment 1, the test method of the hydraulic vacuum assist braking system specifically includes:

[0086] Step S1, vehicle preheating: During the process of the vehicle driving at a constant speed, perform braking stops and accelerations at intervals, and check whether the vehicle reaches the normal working temperature after preheating ends;

[0087] Step S2, adjust the vehicle vacuum degree: Adjust the vacuum pressure regulating valve to simulate low vacuum conditions, gradually increase the vacuum pressure value starting from 0 kPa until the hydraulic vacuum assist braking system is no longer activated;

[0088] Step S3-1, gently step on the brake: Slowly step on the brake pedal, gradually increase the pedal travel until the anti-lock braking system ABS starts to work or a certain wheel locks up, and record various data during the test process;

[0089] Step S3-2, quickly step on the brake: Quickly step on the brake pedal, quickly step on the brake pedal to a certain position and keep it unchanged until the vehicle stops, and record various data during the test process;

[0090] Adjust the vacuum pressure regulating valve again to adjust the vehicle vacuum state until the test conditions are met or the test ends.

[0091] Step S4, data processing: Analyze the vibration of the brake pedal and the noise beside the driver's ear by using a color contour map of the auto power spectral density tracking time, calculate the average braking deceleration, and correct the braking distance.

[0092] Step S5, result evaluation: Evaluate whether the boosting timing, boosting effect, pressure building gradient, and braking performance of the hydraulic vacuum booster assisted braking system are appropriate during braking under the condition of turning on the hydraulic vacuum booster assisted braking, and whether the boosting noise and pedal vibration are obvious.

[0093] As Figures 3 to 5 shown, when in the emergency braking condition, on the premise of the same vacuum degree, turn on or off the hydraulic vacuum booster assisted braking system, and compare the different braking distances, average braking decelerations, and brake pipeline pressures through a bar chart. It can be seen that on the premise of the same vacuum degree: for the braking distance, turning off the hydraulic vacuum booster assisted system will cause an increase in the braking distance and a reduction in braking performance; for the average braking deceleration and the front brake pipeline pressure, turning on the hydraulic vacuum booster assisted system can significantly increase the average braking deceleration and the front brake pipeline pressure value.

[0094] Based on the above test method of the hydraulic vacuum booster assisted braking system, the present invention also provides an application of the test method of the hydraulic vacuum booster assisted braking system as described. By implementing the test method of the hydraulic vacuum booster assisted braking system provided by the present invention and its application, corresponding technical effects can be achieved in vehicle testing. This embodiment reveals the test method of the hydraulic vacuum booster assisted braking system and its application from an overall perspective. Those skilled in the art can obtain other embodiments without creative efforts. Next, the technical solutions in the embodiments of the present invention will be described more clearly and completely with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0095] Embodiment 2: The specific steps of the test method of the hydraulic vacuum booster assisted braking system include:

[0096] Vehicle preheating: The vehicle travels at a constant speed of 70 km / h, brakes and stops every 2.5 km of driving, and does this for a total of 4 times. After stopping, quickly accelerate to 70 km / h and drive at a constant speed, and then perform the next braking (except for the last time). After the preheating is completed, the vehicle should reach the normal working temperature, and the brake temperature should be maintained between 80°C and 100°C, and the brake temperature should be maintained within this temperature range before each braking starts.

[0097] Slowly depress the brake: Adjust the vacuum regulator valve to simulate a low vacuum condition. Gradually adjust the vacuum degree in 10 kPa increments starting from 0 kPa until the hydraulic vacuum booster assisted braking system is no longer activated. Slowly depress the brake pedal, increasing the pedal stroke at an increment of approximately 25 mm / s (or the pedal force at 50 N / s to 100 N / s) until the anti-lock braking system (ABS) starts to operate or a wheel locks up. During the test, record the vacuum degree, vehicle speed, distance, pedal force, braking deceleration, pipeline pressure (if a sensor is installed), braking pedal vibration (if a sensor is installed), and driver's ear-side noise (if a sensor is installed). Conduct two tests for each vacuum degree. Conduct the tests separately in two states: with the hydraulic vacuum booster assisted braking system on and off, and compare the differences in braking pedal characteristics between the two states.

[0098] Quickly depress the brake: Adjust the vacuum regulator valve to simulate a low vacuum condition. Gradually adjust the vacuum degree in 10 kPa increments starting from 0 kPa until the hydraulic vacuum booster assisted braking system is no longer activated. Quickly depress the brake pedal, rapidly stepping on the brake pedal to a certain position at a speed not lower than 250 mm / s and keeping it unchanged until the vehicle stops. The average pedal force applied is 500 N or reaches the full cycle adjustment of the ABS. During the test, record the vacuum degree, vehicle speed, distance, pedal force, braking deceleration, pipeline pressure (if a sensor is installed), braking pedal vibration (if a sensor is installed), and driver's ear-side noise (if a sensor is installed). Conduct two tests for each vacuum degree. Conduct the tests separately in two states: with the hydraulic vacuum booster assisted braking system on and off, and compare the differences in average braking deceleration and braking distance between the two states.

[0099] Data processing: Use the color contour map of the auto-power spectral density tracking time to analyze the braking pedal vibration and the driver's ear-side noise; calculate the average braking deceleration according to a = v2 / (25.92×s) (where v is the vehicle speed when actuating the brake pedal, and s is the distance traveled from actuating the brake pedal to the vehicle stopping); correct the braking distance according to sX = s×(v2G / v2) (where vG is the specified initial vehicle speed, v is the vehicle speed when actuating the brake pedal, and s is the distance traveled from actuating the brake pedal to the vehicle stopping).

[0100] Result evaluation: Evaluate whether the boost timing, boost effect, pressure build-up gradient, braking efficiency, etc. of the system during braking are appropriate under the condition of the hydraulic vacuum booster assisted braking being turned on, and whether the boost noise and pedal vibration are obvious. Compare the differences in pipeline pressure, average braking deceleration, and corrected braking distance values between the working conditions of the hydraulic vacuum booster assisted braking system being on and off under the same vacuum degree conditions (0 kPa, 10 kPa, 20 kPa...), and draw a comparison chart of the test curves for the hydraulic vacuum booster assisted braking system being on and off.

[0101] Example 2 is a further extension and supplement based on Example 1. This example can be combined with any of the above or below examples to form more examples. Whether this example or other single examples, combined examples, etc., none of them limit the protection scope of the claims of the present invention.

[0102] The following examples compare the differences in pipeline pressure, average braking deceleration, and braking distance correction values under the conditions of turning on and off the hydraulic vacuum assist braking system at the same vacuum degree (adjusted in increments (step sizes) of 0 kPa, 10 kPa, 20 kPa...), and draw a comparison chart of the test curves for turning on and off the hydraulic vacuum assist braking system.

[0103] Example 3:

[0104] As Figure 6 and Figure 7 shown and in combination with Table 1-1 and Table 1-2, Figure 6 the abscissa is the pedal force and the ordinate is the deceleration; Figure 7 the abscissa is the pedal force and the ordinate is the pipeline pressure value. The experimental conditions are a vacuum degree of 0 kPa, and a comparison chart of turning on and off the hydraulic vacuum assist braking system.

[0105] Table 1-1:

[0106]

[0107] Table 1-2:

[0108]

[0109] Example 4:

[0110] As Figure 8 and Figure 9 shown and in combination with Table 2-1 and Table 2-2, Figure 8 the abscissa is the pedal force and the ordinate is the deceleration; Figure 9 the abscissa is the pedal force and the ordinate is the pipeline pressure value. The experimental conditions are a vacuum degree of 10 kPa, and a comparison chart of having and not having hydraulic braking assistance:

[0111] Table 2-1

[0112]

[0113] Table 2-2:

[0114]

[0115] Example 5:

[0116] like Figure 10 and Figure 1 As shown in Table 3-1 and Table 3-2, Figure 10 The horizontal axis is the pedal force, and the vertical axis is the deceleration; Figure 11 The horizontal axis is the pedal force, the vertical axis is the pipeline pressure value, the experimental condition is a vacuum degree of 20kPa, and the comparison chart with and without hydraulic brake assist is as follows:

[0117] Table 3-1

[0118]

[0119] Table 3-2

[0120]

[0121] Example 6:

[0122] like Figure 12 and Figure 13 As shown in Table 4-1 and Table 4-2, Figure 12 The horizontal axis is the pedal force, and the vertical axis is the deceleration; Figure 13 The horizontal axis is the pedal force, the vertical axis is the pipeline pressure value, the experimental condition is a vacuum degree of 30kPa, and the comparison chart with and without hydraulic brake assist is as follows:

[0123] Table 4-1

[0124]

[0125] Table 4-2

[0126]

[0127] Example 7:

[0128] like Figure 14 and Figure 15 As shown in Table 5-1 and Table 5-2, Figure 14 The horizontal axis is the pedal force, and the vertical axis is the deceleration; Figure 15 The horizontal axis is the pedal force, the vertical axis is the pipeline pressure value, the experimental condition is a vacuum degree of 40kPa, and the comparison chart with and without hydraulic brake assist is as follows:

[0129] Table 5-1

[0130]

[0131] Table 5-2

[0132]

[0133] Example 8:

[0134] As Figure 16 and Figure 17 shown and combined with Table 6-1 and Table 6-2, Figure 16 in which the abscissa is the pedal force and the ordinate is the deceleration; Figure 17 in which the abscissa is the pedal force and the ordinate is the pipeline pressure value, and the experimental condition is a vacuum degree of 50 kPa, and the comparison chart of hydraulic brake assist and no hydraulic brake assist:

[0135] Table 6-1

[0136]

[0137] Table 6-2

[0138]

[0139] Example 9:

[0140] As Figure 18 and Figure 19 shown and combined with Table 7-1 and Table 7-2, Figure 18 in which the abscissa is the pedal force and the ordinate is the deceleration; Figure 19 in which the abscissa is the pedal force and the ordinate is the pipeline pressure value, and the experimental condition is a vacuum degree of 60 kPa, and the comparison chart of hydraulic brake assist and no hydraulic brake assist:

[0141] Table 7-1

[0142]

[0143] Table 7-2

[0144]

[0145] Example 10:

[0146] As Figure 20 and Figure 21 shown and combined with Table 8-1 and Table 8-2, Figure 20 [[ID=,61]]in which the abscissa is the pedal force and the ordinate is the deceleration; Figure 21 in which the abscissa is the pedal force and the ordinate is the pipeline pressure value, and the experimental condition is a vacuum degree of 70 kPa, and the comparison chart of hydraulic brake assist and no hydraulic brake assist:

[0147] Table 8-1

[0148]

[0149] Table 8-2

[0150] It should be noted that there is a small error in the translation of line 61, which should be "in which the abscissa is the pedal force and the ordinate is the deceleration;" instead of "in which the abscissa is the pedal force and the ordinate is the deceleration; ". This is a clerical error in the original text, and the translation has been corrected accordingly.

[0151] Example 11:

[0152] As Figure 22 and Figure 23 shown and in combination with Table 9-1 and Table 9-2, Figure 22 the abscissa therein is the pedal force and the ordinate is the deceleration; Figure 23 the abscissa therein is the pedal force and the ordinate is the pipeline pressure value, the experimental condition is the maximum vacuum degree, and the comparison charts with and without hydraulic brake assist:

[0153] Table 9-1

[0154]

[0155] Table 9-2

[0156]

[0157] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0158] Those skilled in the art of this technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as the general understanding of those of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined.

[0159] In this patent, unless otherwise clearly stipulated and defined, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this invention can be understood according to specific situations.

[0160] For the method embodiments, for the sake of simplicity in description, they are all expressed as a series of combinations of actions. However, those skilled in the art should be aware that the embodiments of the present invention are not limited by the described order of actions. Because according to the embodiments of the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily essential for the embodiments of the present invention.

[0161] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0162] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A test method for a hydraulic vacuum assisted braking system, characterized in that, Specifically include: Vehicle preheating: During the process of the vehicle driving at a constant speed, perform braking stops and accelerations at intervals, and check whether the vehicle reaches the normal operating temperature after preheating ends; Adjust the vacuum pressure regulating valve to simulate low vacuum conditions: Gradually increase the vacuum pressure value starting from 0 kPa until the hydraulic vacuum assist braking system is no longer activated; Gently step on the brake: Slowly step on the brake pedal and gradually increase the pedal travel until the anti-lock braking system (ABS) starts to work or a certain wheel locks up. Record various data during the test process; Suddenly step on the brake: Quickly step on the brake pedal, quickly step on the brake pedal to a certain position and keep it unchanged until the vehicle stops. Record various data during the test process; Adjust the vacuum pressure regulating valve again to adjust the vehicle vacuum state; Data processing: Use a color contour map of the auto power spectral density tracking time to analyze the vibration amount of the brake pedal and the noise near the driver's ear, calculate the average braking deceleration, and correct the braking distance; Result evaluation: Evaluate whether the boost timing, boost effect, pressure build-up gradient, and braking efficiency of the hydraulic vacuum assist braking system during braking under the condition of activating the hydraulic vacuum assist braking are appropriate, and whether the boost noise and pedal vibration are obvious; Among them, the gentle stepping on the brake specifically includes: Adjust the vacuum pressure regulating valve to simulate low vacuum conditions, gradually adjust the vacuum degree starting from 0 kPa in increments of 10 kPa until the hydraulic vacuum assist braking system is no longer activated, and slowly step on the brake pedal until the anti-lock braking system (ABS) starts to work or a certain wheel locks up; Among them, the slowly stepping on the brake pedal specifically means: Increase the pedal travel at a speed of 25 mm / s or increase the pedal force in increments of 50 N / s to 100 N / s until the anti-lock braking system (ABS) starts to work or a certain wheel locks up; Among them, the suddenly stepping on the brake specifically includes: Adjust the vacuum pressure regulating valve to simulate low vacuum conditions, gradually adjust the vacuum degree starting from 0 kPa in increments of 10 kPa until the hydraulic vacuum assist braking system is no longer activated, and quickly step on the brake pedal, step on the brake pedal to a certain position and keep it unchanged until the vehicle stops; Among them, the quickly stepping on the brake pedal specifically means: Step on the brake pedal to a certain position at a speed not lower than 250 mm / s and keep it unchanged until the vehicle stops, and the average pedal force applied is 500 N or reaches the full cycle adjustment of the ABS; 2. The test method of the hydraulic vacuum assisted braking system according to claim 1, characterized in that, The vehicle preheating specifically includes: Vehicle preheating: The vehicle drives at a constant speed of 70 km / h, performs a braking stop every 2.5 km of driving, performs a total of 4 times, accelerates to 70 km / h after stopping and drives at a constant speed, and then performs the next braking. After preheating ends, the vehicle should reach the normal operating temperature, the brake temperature should be kept between 80°C and 100°C, and the brake temperature should be kept within this temperature range before each braking starts.

3. The test method of the hydraulic vacuum assist braking system according to claim 1, characterized in that The data processing specifically includes: Use a color contour map of the auto power spectral density tracking time to analyze the vibration amount of the brake pedal and the noise near the driver's ear; Calculate the average braking deceleration according to a = v 2 / (25.92 × s), where v is the vehicle speed when the brake pedal is actuated, and s is the distance traveled from actuating the brake pedal to the vehicle coming to a stop; The braking distance is corrected according to s X = s×(v 2 G / v 2 ), where v G is the specified initial vehicle speed, v is the vehicle speed when the brake pedal is actuated, and s is the distance traveled from actuating the brake pedal to the vehicle coming to a stop.

4. The test method of the hydraulic vacuum assisted braking system according to claim 1, characterized in that The result evaluation specifically includes: Evaluate whether the boost timing, boost effect, pressure build-up gradient, and braking performance of the system are appropriate during braking under the condition of activating the hydraulic vacuum boost assisted braking, and whether the boost noise and pedal vibration are obvious; Compare the differences in pipeline pressure, average braking deceleration, and braking distance correction value between the working conditions of activating and deactivating the hydraulic vacuum boost assisted braking system under the same vacuum degree condition; The specific condition of comparing the same vacuum degree is as follows: starting from 0 kPa, the vacuum degree is gradually increased in increments of 10 kPa; Draw a comparison chart of the test curves of activating and deactivating the hydraulic vacuum boost assisted braking system.

5. The test method of the hydraulic vacuum assist braking system according to any one of claims 1 to 3, characterized in that, During the test, record the vacuum degree, vehicle speed, distance, pedal force, braking deceleration, pipeline pressure, braking pedal vibration amount, and driver's ear side noise. Each test is repeated twice for each vacuum degree, and the test is carried out separately in the two states of activating and deactivating the hydraulic vacuum boost assisted braking system, and compare the differences in the braking pedal characteristics between the two states; Among them, the test method at least meets the following sensor installation requirements: Vibration acceleration sensor: The vibration acceleration sensor is installed on the acting surface of the braking pedal. The Z-axis of the sensor is perpendicular to the acting surface of the braking pedal, and the X-axis of the sensor is in the same plane as the vehicle X-axis; Miniature microphone sensor: Measure the noise beside the driver's right ear. The direction of the maximum sensitivity of the miniature microphone sensor is consistent with the driver's line of sight; the distance between the sensor and the vehicle compartment wall or seat cushion is greater than 0.15 m, the vertical position is (0.7 ± 0.05) m above the seat surface when there is no one, and the horizontal position is (0.2 ± 0.02) m behind the vertical plane where the front and rear center lines of the seat surface are located.

6. Application of a test method for a hydraulic vacuum boost assisted braking system according to any one of claims 1 to 4 in vehicle testing.

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