Axle load adjusting method applied to suspension system of passenger car and passenger car

Abstract

The invention relates to an axle load adjusting method applied to a suspension system of a passenger car and the passenger car, and belongs to the field of vehicle manufacturing. The adjusting method comprises the steps that the axle loads of three axles are adjusted in advance, so that the axle loads of the three axles meet the requirements of axle load regulations; the axle load of the second axle is calculated according to the total mass of the passenger car, the distance between the mass center and the first axle, the distance between the first axle and the second axle, the distance between the first axle and the third axle and the axle load of the third axle; calculating the axle load of the first axle by utilizing the axle load of the second axle, the axle load of the third axle and the total mass; judging whether the axle load of the first axle and the axle load of the second axle meet the axle load regulation requirements or not; when the axle load regulation requirements are not met, the axle load of the third axle is adjusted until the axle load of the first axle and the axle load of the second axle meet the axle load regulation requirements; wherein a first shaft and a second shaft of the passenger car are plate spring suspensions, and a third shaft of the passenger car is an air bag suspension. Under the condition that the plate spring is not replaced, the requirements of axle load laws and regulations can be met, economic benefits can be improved, and the adjusting process is simple.

Description

Technical Field

[0001] The invention relates to an axle load adjustment method for a suspension system of a bus and the bus, and belongs to the field of vehicle manufacturing. Background Art

[0002] With the continuous development of the transportation industry, three-axle buses with greater load capacity and higher operating economy are becoming more and more popular in the market compared to two-axle buses.

[0003] At present, the structure of three-axle buses is divided into two categories, one is the chassis structure with full air suspension on three axles, and the other is the chassis structure with full leaf spring suspension on three axles. The three-axle chassis with full air suspension has the advantage of high ride comfort, but the structure is relatively complex and the reliability is poor; the three-axle chassis with full leaf spring suspension has the advantage of high reliability, but the problem of poor ride comfort. Whether it is a chassis structure with full air suspension on three axles or a chassis structure with full leaf spring suspension on three axles, after the design is completed, the maximum axle load distribution of each axle is fixed and cannot be adjusted, so it cannot meet the different axle load requirements of different countries' markets for different axles, resulting in low economic benefits.

[0004] The Chinese invention patent application with application publication number CN102407748A discloses a new type of support axle load control system. The new type of support axle load control system includes: a front axle, a drive shaft and a support axle, wherein the front axle is arranged in front of the axle load control system and is a leaf spring suspension; the support axle is arranged in the rear of the axle load control system and is an air suspension, the air suspension includes a bag-type airbag, and the bag-type airbag is connected to a controller; the drive shaft is arranged in front of the support axle and is a leaf spring suspension. The method of using the invention comprises the following steps: (1) by setting the static deflection of the leaf spring and the stiffness value of the leaf spring, the minimum value of the load on the drive shaft is determined to ensure that the vehicle has sufficient driving force; by using the bag-type airbag, the load on the rear of the vehicle is shared to ensure that the load on the drive shaft does not exceed the standard limit; (2) when the vehicle is unloaded, the height valve is set to the middle position, the air circuit is in a closed state, the weight is mainly borne by the drive shaft, and the support shaft has a small load or no load; (3) as the vehicle is loaded with passengers, the load increases, the vehicle height decreases, the height valve opens, the air circuit is in an open state, the air pressure of the airbag increases, and when the vehicle height returns to the unloaded height of the vehicle, the height valve closes, the load continues to increase, and the above process is repeated until the air pressure of the airbag reaches the set pressure value. At this stage, the increased load of the vehicle is all borne by the support shaft. The scheme uses the height valve to control the vehicle height and the axle load distribution between the drive shaft and the support shaft, so that when the vehicle is unloaded, the load on the drive shaft is minimized to ensure that the vehicle has sufficient driving force; when the bus is fully loaded, the support shaft bears more load to ensure that the axle load on the drive shaft does not exceed the standard limit. However, this method does not take the axle load of the front axle into consideration, and may still result in the axle load of the bus not meeting the standard restrictions of the country to be exported. When the axle load of the front axle does not meet the limit standards of the country to be exported, replacing the leaf spring parameters of the front axle will result in lower economic benefits. In addition, the entire process needs to refer to the airbag characteristic curve, and the adjustment method is not flexible. Summary of the invention

[0005] The purpose of the present invention is to provide an axle load adjustment method for a suspension system of a bus and a bus, so as to solve the problem in the prior art that when the axle load of the bus does not meet the standard restrictions of the country to be exported, the leaf spring needs to be replaced, resulting in low economic benefits.

[0006] To achieve the above object, the solution of the present invention includes:

[0007] The present invention provides an axle load adjustment method for a suspension system of a bus, comprising the following steps:

[0008] Pre-adjust the axle loads of the three axes to ensure that they meet the axle load regulations;

[0009] Calculate the axle load of the second axle using the total mass of the bus, the distance between the center of mass and the first axle, the distance between the first axle and the second axle, the distance between the first axle and the third axle, and the axle load of the third axle;

[0010] Calculating the axle load of one axle using the axle loads of the two axles, the axle loads of the three axles and the total mass;

[0011] Determining whether the axle load of the first axle and the axle load of the second axle meet the axle load regulations;

[0012] When the axle load regulations are not met, adjusting the axle loads of the three axles until the axle loads of the first axle and the axle loads of the second axle meet the axle load regulations;

[0013] Among them, the first and second axles of the bus are leaf spring suspensions, and the third axle is air bag suspension.

[0014] Furthermore, the axle load of the second axle=(total mass of the bus×the distance between the center of mass and the first axle−the axle load of the third axle×the distance between the first axle and the third axle) / the distance between the first axle and the second axle.

[0015] Furthermore, the axle load of the first axle=the total mass of the bus-the axle load of the second axle-the axle load of the third axle.

[0016] Furthermore, the total mass of the bus is determined according to the number of passengers in the bus and the cargo capacity of the bus cabin.

[0017] Furthermore, it also includes: when the airbag gas pressure in the airbag suspension exceeds the overflow pressure threshold, gas overflows to maintain the airbag gas pressure unchanged.

[0018] A bus of the present invention comprises a controller, a first axle and a second axle; the first axle and the second axle are leaf spring suspensions, the third axle is an airbag suspension, and the controller executes a computer program to implement the following steps:

[0019] Pre-adjust the axle loads of the three axes to ensure that the axle loads of the three axes meet the axle load regulations;

[0020] Calculate the axle load of the second axle using the total mass of the bus, the distance between the center of mass and the first axle, the distance between the first axle and the second axle, the distance between the first axle and the third axle, and the axle load of the third axle;

[0021] Calculating the axle load of one axle using the axle loads of the two axles, the axle loads of the three axles and the total mass;

[0022] Determining whether the axle load of the first axle and the axle load of the second axle meet the axle load regulations;

[0023] When the axle load regulations are not met, the axle loads of the three axles are adjusted until the axle load of the one axle and the axle load of the two axles meet the axle load regulations.

[0024] Furthermore, the axle load of the second axle=(total mass of the bus×the distance between the center of mass and the first axle−the axle load of the third axle×the distance between the first axle and the third axle) / the distance between the first axle and the second axle.

[0025] Furthermore, the axle load of the first axle=the total mass of the bus-the axle load of the second axle-the axle load of the third axle.

[0026] Furthermore, the total mass of the bus is determined according to the number of passengers in the bus and the cargo capacity of the bus cabin.

[0027] Furthermore, the controller is also used to execute the following steps: when the airbag gas pressure in the airbag suspension exceeds the overflow pressure threshold, opening the overflow valve to maintain the airbag gas pressure unchanged.

[0028] The beneficial effects of the present invention are as follows: as a pioneering invention, the present invention provides an axle load adjustment method for a suspension system of a bus and a bus. Since the load of a three-axle bus is mainly on the first and second axles, the bump behind the second axle is more serious than the bump in front of the second axle, therefore, by setting the first and second axles of the three-axle bus as leaf spring suspensions and the three axles of the three-axle bus as airbag suspensions, the three-axle bus can meet the reliability requirements while taking into account the comfort of passengers. According to the axle load requirements for the three axles in the axle load regulations, the axle loads of the three axles are adjusted in advance; the axle loads of the two axles are calculated using the total mass of the three-axle bus, the distance between the center of mass and the first axle, the distance between the first axle and the second axle, the distance between the first axle and the third axle, and the axle loads of the three axles; the axle loads of the first axle are calculated using the axle loads of the second axle, the axle loads of the third axle, and the total mass of the three-axle bus; after calculating the axle loads of the first axle and the second axle, it is determined whether the axle loads of the first axle and the second axle meet the axle load regulations; when the axle loads of the first axle and the second axle do not meet the axle load regulations, the axle loads of the three axles can be adjusted by adjusting the pressure of the airbag again, and then the axle loads of the first axle and the second axle are indirectly adjusted until the axle loads of the first axle and the second axle meet the axle load regulations. Since the entire process does not require the replacement of leaf springs, the axle loads of the first axle and the second axle can be indirectly adjusted by adjusting the axle loads of the three axles, so that the axle loads of the first axle and the second axle can meet the requirements, so the economic benefits will be improved. In addition, since the entire adjustment process does not require reference to any curve, the axle loads of one axis and two axes can meet the axle load regulations only by adjusting the axle loads of the three axes. The process is flexible, simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a structural schematic diagram of a suspension system of a passenger car provided by an embodiment of the present invention;

[0030] Figure 2 The present invention is a flowchart of an axle load adjustment method for a suspension system of a passenger car provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0032] The concept of the present invention is to indirectly control the axle loads of the first and second axes by controlling the axle loads of the three axes.

[0033] Specifically, since the load of a three-axle bus is mainly on the first and second axles, and the bumps behind the second axle are more serious than those in front of the second axle, the first and second axles of the three-axle bus can be set to leaf spring suspensions, and the third axle of the three-axle bus can be set to air bag suspensions. This allows the three-axle bus to meet reliability while taking into account passenger comfort. Since the three axles are air bag suspensions and the axle loads are adjustable, the axle loads of the three axles can be pre-adjusted according to the axle load requirements for the three axles in the axle load regulations; the axle load of the second axle is calculated using the total mass of the three-axle bus, the distance between the center of mass and the first axle, the distance between the first axle and the second axle, the distance between the first axle and the third axle, and the axle load of the three axles; the axle load of the first axle is calculated using the axle load of the second axle, the axle load of the third axle, and the total mass of the three-axle bus; after calculating the axle loads of the first axle and the second axle, determine the axle loads of the first axle and the second axle. Whether the load meets the requirements of axle load regulations; since the total mass of a three-axle bus, the distance between the center of mass and the first axle, the distance between the first axle and the second axle, and the distance between the second axle and the third axle are fixed, and the first axle and the second axle are leaf spring suspensions, and the axle load adjustment is difficult, therefore, when the axle load of the first axle and the axle load of the second axle do not meet the requirements of the axle load regulations, the axle load of the three axles can be adjusted by adjusting the pressure of the airbag again, and then the axle load of the first axle and the axle load of the second axle can be adjusted indirectly, until the axle load of the first axle and the axle load of the second axle meet the requirements of the axle load regulations.

[0034] An embodiment of an axle load adjustment method for a suspension system of a bus:

[0035] The embodiment of the present invention provides an axle load adjustment method for a suspension system of a bus, which relies on a suspension system of a bus in which the first and second axles are leaf spring suspensions and the third axle is airbag suspension. The specific suspension system of the bus can be referred to Figure 1 .

[0036] Figure 1 is a schematic diagram of the structure of a passenger car suspension system provided by an embodiment of the present invention, such as Figure 1 As shown, the suspension system of the bus includes one axle, two axles and three axles, wherein the one axle and the two axles are configured as leaf spring suspensions, and the three axles are configured as air bag suspensions.

[0037] Among them, the airbag suspension includes: an airbag air cylinder 40, a pressure limiting valve 30, a height valve 20 and an airbag 50 arranged on three axes; the airbag air cylinder 40 is used to provide gas for the airbag 50, and the air outlet of the airbag air cylinder 40 is connected to the air inlet of the pressure limiting valve 30; the pressure limiting valve 30 is used to control and change the output gas pressure of the airbag air cylinder 40, and the air outlet of the pressure limiting valve 30 is connected to the air inlet of the height valve 20; the height valve 20 is used to adjust the balance and height of the airbag 50, and the air outlet of the height valve 20 is connected to the airbag 50.

[0038] In order to protect the airbag 50, as an optional embodiment, the suspension system of the bus may further include a relief valve 10. When the suspension system of the bus further includes the relief valve 10, the relief valve 10 is disposed on the pipeline connecting the height valve 20 and the airbag 50, and the air outlet of the relief valve 10 is connected to the outside air. The relief valve 10 is used to overflow gas when the pressure of the airbag exceeds the threshold value of the relief valve 10, so as to maintain the gas pressure of the airbag 50 unchanged, thereby protecting the airbag 50.

[0039] Combine the following Figure 1 and Figure 2 , describing the specific process of an axle load adjustment method for a suspension system of a bus provided by an embodiment of the present invention.

[0040] Figure 2 FIG. 1 is a flow chart of an axle load adjustment method for a suspension system of a passenger car provided by an embodiment of the present invention. Figure 2 As shown, the specific steps include:

[0041] First, in combination with the relevant requirements of axle load regulations and design specifications, each axle load is calculated, and the leaf spring parameters of the leaf spring suspension of the first and second axes are matched according to the calculation results, and the air pressure of the airbag 50 in the airbag suspension of the third axis is matched.

[0042] Different countries have different requirements for axle load regulations. For example, Tanzania requires that one axle should not exceed 8 tons, and the second and third axles should not exceed 15 tons; for another example, South Africa requires that one axle should not exceed 7.7 tons, the second axle should not exceed 10.2 tons, and the third axle should not exceed 8 tons, and so on.

[0043] S101. Pre-adjust the axle load G3 of the three axes so that the axle load G3 of the three axes meets the axle load regulations.

[0044] Specifically, according to the airbag pressure calculated above, the threshold of the pressure limiting valve 30 is set so that the gas in the airbag cylinder 40 outputs an air pressure that meets the threshold of the pressure limiting valve 30. The air pressure that meets the threshold of the pressure limiting valve 30 enters the airbag through the height valve 20 and the overflow valve 10, so that the axle load G3 of the three axes meets the axle load regulations of relevant countries and the restriction requirements for the three-axis axle load.

[0045] S102. Calculate the axle load G2 of the second axle using the total mass M of the bus, the distance L between the center of mass m and the first axle, the distance a between the first axle and the second axle, the distance b between the first axle and the third axle, and the axle load G3 of the third axle.

[0046] Specifically, the axle load G2 of the two axes can be calculated according to the mass moment formula. The mass moment formula can refer to the following formula (1):

[0047] M×L=G2×a+G3×b (1)

[0048] The axle load G2 of the two axes is calculated. The expression of the axle load G2 of the two axes can refer to the following formula (2):

[0049] G2=(M×L-G3×b) / a (2)

[0050] Among them, the total mass M of the bus is the maximum total mass of the bus, which can be calculated based on the weight of the bus when it is fully loaded with passengers, the maximum cargo capacity of the cabin and other configuration requirements.

[0051] The center of mass m is related to the total mass M of the bus. The center of mass m can be configured based on the center of mass test data of the sample vehicle in the previous test, combined with various addition or deletion operations. The position of the center of mass m is used as an example in the following description when the vehicle is fully loaded.

[0052] It can be understood that after the centroid m, axis 1, axis 2 and axis 3 are set, the wheelbase a between axis 1 and axis 2, the wheelbase b between axis 1 and axis 3, and the distance L between the centroid m and axis 1 are fixed. Choosing to calculate G2 using M, L, a, b and G3 is in line with the control variable method on the one hand, and on the other hand, since M, L, a, b are quantitative and only G3 is a variable, therefore, only G3 needs to be changed to change G2, and the adjustment process is simple and easy to operate.

[0053] S103, calculate the axle load G1 of the first axle using the axle load G2 of the second axle, the axle load G3 of the third axle and the total mass M of the bus.

[0054] Specifically, the expression of the axle load G1 of an axle can refer to the following formula (3):

[0055] G1=M-G2-G3 (3)

[0056] S104, judging whether the axle load G1 of the first axis and the axle load G2 of the second axis meet the axle load regulations; if they do not meet the axle load regulations, adjusting the axle load G3 of the three axes until the axle load G1 of the first axis and the axle load G2 of the second axis meet the axle load regulations.

[0057] Because the axle load requirements for three axles in the axle load regulations of various countries are relatively loose, the axle loads of the three axles are allowed to be outside the axle load limit range, while the axle load requirements for one and two axles are relatively strict and must be within the axle load limit range. Therefore, after the axle load G2 of the two axles is calculated through step S102 and the axle load G1 of the one axle is calculated through step S103, first determine whether the axle load G1 of the one axle and the axle load G2 of the two axles meet the axle load regulations. If yes, the axle load G3 of the three axles will not be adjusted.

[0058] When it does not meet the requirements, since both the first and second axles use leaf spring suspension, if you want to directly adjust the axle load G1 of the first axle and the axle load G2 of the second axle, you must replace the leaf spring and its accessories. This process is cumbersome, has low economic benefits, and is difficult to implement. Therefore, after knowing the relationship expressions between the axle load G1 of the first axle, the axle load G2 of the second axle and the axle load G3 of the third axle, the axle load G1 of the first axle and the axle load G2 of the second axle can be indirectly adjusted by adjusting the axle load G3 of the third axle.

[0059] The following specifically describes how to adjust the axle load G3 of the three axes so that the axle load G1 of the first axis and the axle load G2 of the second axis meet the axle load regulations.

[0060] Assuming that the axle load G2 of the second axle is greater than the axle load regulations require, the axle load G2 of the second axle needs to be reduced.

[0061] Specifically, the threshold value of the pressure-limiting valve 30 is increased, so that the pressure of the gas output from the airbag air cylinder 40 increases, and the gas enters the airbag 50 after passing through the height valve 20 and the overflow valve 10. The air pressure of the airbag 50 increases, so that the axle load G3 of the three axes increases.

[0062] Under the premise of ensuring that the axle load G3 of the three axes is less than the maximum load limit and the regulatory limit, after the axle load G3 of the three axes increases, according to formula (2), since M, L, a and b are constants, the difference of M×L-G3×b will decrease, so the axle load G2 of the two axes will decrease, that is, the axle load G2 of the two axes will decrease.

[0063] Substituting formula (2) into formula (3), another calculation formula for calculating the axle load G1 of an axle can be obtained, as shown in formula (4):

[0064]

[0065] It can be seen from this that when the axle load G3 of the three axes changes, the axle load G1 of one axis will also change, that is, when the axle load G3 of the three axes increases, the axle load G1 of one axis will also increase. Therefore, in the process of adjusting the axle load G3 of the three axes to reduce the axle load G2 of the two axes, it is also necessary to pay attention to the axle load change of the axle load G1 of one axis until the adjustment is completed so that the axle loads of one and two axes meet the axle load regulations.

[0066] The threshold value of the pressure-limiting valve 30 may be reduced or increased manually or by a controller, and the present invention does not specifically limit this.

[0067] In order to prevent the air pressure in the airbag 50 from being too high during the adjustment process, which may cause the airbag 50 to explode and be detrimental to the long-term use of the airbag 50, as an optional implementation, the axle load adjustment method for the suspension system of a bus provided in the embodiment of the present invention may further include step S105. That is, when the gas pressure of the airbag 50 in the airbag suspension exceeds the overflow pressure threshold, the gas overflows to maintain the airbag gas pressure unchanged.

[0068] S105. When the airbag gas pressure in the airbag suspension exceeds the overflow pressure threshold, gas overflows to maintain the airbag gas pressure unchanged.

[0069] When the pressure in the airbag exceeds the threshold of the relief valve, the outlet of the relief valve 10 connected to the outside air is opened to release excess gas to maintain the airbag gas pressure unchanged.

[0070] The overflow valve 10 may be opened manually, or may be opened by a controller (ie, the electronically controlled overflow valve is opened), etc., and the present invention does not specifically limit this.

[0071] An embodiment of the present invention provides an axle load adjustment method for a suspension system applied to a bus. By setting the first and second axles of the bus as leaf spring suspensions and setting the three axles of a three-axle bus as airbag suspensions, the bus can meet the requirements of reliability while taking into account the comfort of passengers. The axle loads of the three axles are adjusted by pre-adjusting the pressure of the airbags so that the axle loads of the three axles meet the axle load regulations. The axle loads of the two axles are calculated by using the total mass of the bus, the distance between the center of mass and the first axle, the distance between the first axle and the second axle, the distance between the first axle and the third axle, and the axle loads of the three axles. The axle loads of the first axle are calculated by using the axle loads of the second axle, the axle loads of the three axles, and the total mass of the bus. After calculating the axle loads of the first axle and the second axle, it is determined whether the axle loads of the first axle and the second axle meet the axle load regulations. When the axle loads of the first axle and the second axle do not meet the axle load regulations, the pressure of the airbags is adjusted again to adjust the axle loads of the three axles, and then the axle loads of the first axle and the second axle are indirectly adjusted until the axle loads of the first axle and the second axle meet the axle load regulations. Since the whole process does not require the replacement of leaf springs, the axle loads of the first axle and the second axle can be indirectly adjusted by adjusting the axle loads of the three axles, so that the axle loads of the first axle and the second axle can meet the requirements, and therefore, the economic benefits will be improved. In addition, since the entire adjustment process does not require reference to any curve, the axle loads of one axis and two axes can meet the axle load regulations only by adjusting the axle loads of the three axes. The process is flexible, simple and easy to implement.

[0072] An embodiment of a passenger car:

[0073] An embodiment of the present invention provides a passenger car, including a controller and a suspension system.

[0074] Among them, the suspension system can refer to the relevant description in the aforementioned "an embodiment of an axle load adjustment method for a suspension system applied to a passenger car", which will not be repeated here.

[0075] The controller executes a computer program to implement the method steps of the axle load adjustment method for the suspension system of a passenger car as described above, which will not be repeated here.

[0076] A passenger car provided by an embodiment of the present invention can achieve the same beneficial effects as the aforementioned axle load adjustment method for a suspension system of a passenger car, which will not be described in detail here.

Claims

1. A method for adjusting the axle load of a suspension system of a passenger car, characterized in that: The steps include: Pre-adjust the axle loads of the three axes to ensure that they meet the axle load regulations; Calculate the axle load of the second axle using the total mass of the bus, the distance between the center of mass and the first axle, the distance between the first axle and the second axle, the distance between the first axle and the third axle, and the axle load of the third axle; Calculating the axle load of one axle using the axle loads of the two axles, the axle loads of the three axles and the total mass; Determining whether the axle load of the first axle and the axle load of the second axle meet the axle load regulations; When the axle load regulations are not met, adjusting the axle loads of the three axles until the axle loads of the first axle and the axle loads of the second axle meet the axle load regulations; Among them, the first and second axles of the bus are leaf spring suspensions, and the third axle is air bag suspension.

2. The axle load adjustment method for a suspension system of a bus according to claim 1, characterized in that: The axle load of the second axle = (total mass of the bus×the distance between the center of mass and the first axle−the axle load of the third axle×the distance between the first axle and the third axle) / the distance between the first axle and the second axle.

3. The axle load adjustment method for a suspension system of a bus according to claim 2, characterized in that: The axle load of the first axle=the total mass of the bus-the axle load of the second axle-the axle load of the third axle.

4. The axle load adjustment method for a suspension system of a bus according to claim 1, characterized in that: The total mass of the bus is determined according to the number of passengers in the bus and the cargo capacity of the bus cabin.

5. The axle load adjustment method for a suspension system of a bus according to any one of claims 1 to 4, characterized in that: Also includes: When the airbag gas pressure in the airbag suspension exceeds the overflow pressure threshold, gas overflows to maintain the airbag gas pressure unchanged.

6. A passenger car, comprising a controller, a first axle and a second axle; the first axle and the second axle are leaf spring suspensions, the third axle is an airbag suspension, characterized in that: The controller executes a computer program to implement the following steps: Pre-adjust the axle loads of the three axes to ensure that they meet the axle load regulations; Calculate the axle load of the second axle using the total mass of the bus, the distance between the center of mass and the first axle, the distance between the first axle and the second axle, the distance between the first axle and the third axle, and the axle load of the third axle; Calculating the axle load of one axle using the axle loads of the two axles, the axle loads of the three axles and the total mass; Determining whether the axle load of the first axle and the axle load of the second axle meet the axle load regulations; When the axle load regulations are not met, the axle loads of the three axles are adjusted until the axle load of the one axle and the axle load of the two axles meet the axle load regulations.

7. The passenger car according to claim 6, characterized in that: The axle load of the second axle = (total mass of the bus×the distance between the center of mass and the first axle−the axle load of the third axle×the distance between the first axle and the third axle) / the distance between the first axle and the second axle.

8. The passenger car according to claim 7, characterized in that: The axle load of the first axle=the total mass of the bus-the axle load of the second axle-the axle load of the third axle.

9. The passenger car according to claim 6, characterized in that: The total mass of the bus is determined according to the number of passengers in the bus and the cargo capacity of the bus cabin.

10. The passenger car according to any one of claims 6 to 9, characterized in that: The controller is also used to execute the following steps: when the airbag gas pressure in the airbag suspension exceeds the overflow pressure threshold, the overflow valve is opened to maintain the airbag gas pressure unchanged.

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