Integrated power chain brake control method

Abstract

The invention relates to an integrated power chain braking control method. The method comprises a constant-speed braking preset condition judgment process, an integrated braking sub-process and a different-cylinder-number braking sub-process. According to the invention, the stepless regulation and control of the braking power are realized by matching the matched linkage of the IAT and the high-power braking; and the influence of the gear of the gearbox on the vehicle speed is synchronously considered, and the downhill at the constant vehicle speed is realized through the gear of the gearbox, engine braking and IAT opening adjustment. High braking power is achieved, potential safety hazards are reduced, and meanwhile the use cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to an integrated power chain braking control method. Background Art

[0002] When heavy vehicles are driving on mines or mountain roads, they have to go down long slopes. In order to prevent the car from accelerating to a dangerous level under the action of its own gravity, the car should be braked continuously, and the part of kinetic energy converted from potential energy will be converted into heat energy and dissipated, so that the speed of the car can be stabilized at a certain safe value. If the braking of heavy trucks now only relies on the continuous operation of the service brake, it is easy to cause the brake to overheat, the braking ability to decline, severe wear, and even cause combustion. Even if the user installs a sprinkler, there are still many safety hazards. With the rapid development of the automobile industry and the continuous improvement of automobile driving performance, people pay more and more attention to the safety of automobiles. Braking performance is one of the important performance of automobiles, and the braking performance of automobiles is directly related to traffic safety. In European and American countries, the accident rate of trucks is much lower than that in China. A very important reason is that auxiliary braking devices are installed on the vehicles.

[0003] Auxiliary braking devices mainly include engine braking, hydraulic retarder, eddy current retarder, etc. Many vehicles are equipped with multiple auxiliary braking devices to cooperate with each other. The hydraulic retarder is mainly selected according to customer needs. Its price cost is relatively high. In long downhill conditions, if the engine cooling system cannot take away the heat of the retarder in time, the oil temperature and water temperature of the retarder will reach the torque limit temperature threshold of the retarder, and the braking power will decrease. Therefore, how to achieve the braking effect by increasing the engine braking power and selecting the appropriate gearbox gear according to the long downhill condition, while canceling the hydraulic retarder and reducing the cost of auxiliary braking has become an urgent problem to be solved.

[0004] The defects of the prior art are:

[0005] 1. In the prior art, if the heavy truck brakes only rely on the continuous operation of the service brakes, it is easy to cause the brakes to overheat, the braking ability to decline, severe wear, and even cause combustion, thus posing a safety hazard.

[0006] 2. In order to meet the braking requirements, the existing technology requires the installation of an auxiliary braking device, which increases the cost.

[0007] 3. In the prior art auxiliary braking device, if the engine cooling system cannot take away the heat of the retarder in time during a long downhill operation, the oil temperature and water temperature of the retarder will reach the torque limit temperature threshold of the retarder, thereby causing a decrease in braking power. Summary of the invention

[0008] In view of the above problems, the present invention provides an integrated power chain braking control method, which aims to achieve high braking power, reduce safety hazards, and reduce use costs.

[0009] To solve the above problems, the technical solution provided by the present invention is:

[0010] The integrated power chain braking control method comprises the following steps:

[0011] S100. Determine whether the current vehicle meets the preset conditions for constant speed braking; then perform the following operations according to the determination result:

[0012] If the vehicle meets the preset condition of constant speed braking, execute S200;

[0013] If the vehicle does not meet the preset condition for constant speed braking, S100 is executed again;

[0014] S200. Determine whether the vehicle driver has a constant speed braking requirement, and then perform the following operations according to the determination result:

[0015] If the driver presses the constant speed brake switch, it is determined that the driver has a constant speed brake demand, and then S300 is executed;

[0016] If the driver does not press the constant speed brake switch, it is determined that the driver has no constant speed brake demand, and then the process returns to and re-executes S100;

[0017] S300. Determine whether the current vehicle speed is within a preset constant vehicle speed range, and then perform the following operations according to the determination result:

[0018] If the current vehicle speed is within the constant vehicle speed range, execute S400;

[0019] If the current vehicle speed is not within the constant vehicle speed interval, return to and re-execute S100;

[0020] S400. Record the current vehicle speed and set the current vehicle speed as the target vehicle speed for constant vehicle speed;

[0021] S500. Record the current vehicle speed in real time, and compare the constant vehicle speed target with the current vehicle speed, and then perform the following operations according to the comparison result:

[0022] If the current vehicle speed is greater than the target vehicle speed of the constant vehicle speed, and the current vehicle speed exceeds the manually preset integrated braking vehicle speed threshold, then S600 is executed;

[0023] If the current vehicle speed is not greater than the target vehicle speed of the constant vehicle speed, or the previous vehicle speed does not exceed the integrated braking vehicle speed threshold, it is determined that braking is not required at present;

[0024] S600. Prioritize the gear shift calculation of the transmission, and perform braking calculation based on the current engine speed and the current transmission gear position and execute the integrated braking sub-process.

[0025] Preferably, the integrated braking sub-process specifically comprises the following steps:

[0026] Sa100. Calculate the first transmission target gear position and the first engine target speed after the current transmission gear position is downgraded by one gear.

[0027] Sa200. Determine whether the first engine target speed exceeds the manually preset engine protection speed threshold, and then perform the following operations according to the determination result:

[0028] If the first target engine speed exceeds the engine protection speed threshold, the maximum cylinder number braking of the engine is turned on, and the maximum braking force is maintained for braking, and then S500 is executed;

[0029] If the first engine target speed does not exceed the engine protection speed threshold, executing Sa300;

[0030] Sa300. Determine whether the required braking force after the gearbox is downshifted by one gear exceeds the maximum braking force of the engine, and then perform the following operations according to the determination result:

[0031] If the required braking force after the gearbox is downshifted by one gear exceeds the maximum braking force of the engine, executing step Sa400;

[0032] If the required braking force after the gearbox is downshifted by one gear does not exceed the maximum braking force of the engine, the gearbox is downshifted by one gear first, and then the braking sub-process with different cylinder numbers is executed;

[0033] Sa400. Calculate the second gearbox target gear and the second engine target speed after the current gearbox gear is downgraded by two gears;

[0034] Sa500. Determine whether the second engine target speed exceeds the engine protection speed threshold, and then perform the following operations according to the determination result:

[0035] If the second engine target speed exceeds the engine protection speed threshold, the maximum cylinder number braking of the engine is turned on, and the maximum braking force is maintained for braking, and then S500 is executed;

[0036] If the second engine target speed does not exceed the engine protection speed threshold, executing Sa600;

[0037] Sa600. Determine whether the required braking force after the gearbox is downshifted by two gears exceeds the maximum braking force of the engine, and then perform the following operations according to the determination result:

[0038] If the required braking force after the gearbox is downshifted by two gears exceeds the maximum braking force of the engine, the maximum cylinder number braking of the engine is turned on, and the maximum braking force is maintained for braking, and then S500 is executed;

[0039] If the required braking force after the transmission gear is downshifted by two gears does not exceed the maximum braking force of the engine, the transmission will be downshifted by two gears first, and then the braking sub-process with different cylinder numbers will be executed.

[0040] Preferably, the braking sub-process with different cylinder numbers specifically comprises the following steps:

[0041] Sb100. Determine whether the current required braking force requires maximum cylinder braking, and then perform the following operations according to the determination result:

[0042] If the current required braking force exceeds the maximum braking force of the engine itself, it is determined that maximum cylinder braking is required, and then Sb200 is executed;

[0043] If the current required braking force does not exceed the maximum braking force of the engine itself, it is determined that maximum cylinder braking is not required, and then Sb300 is executed;

[0044] Sb200. Perform maximum cylinder braking and stepless adjustment of braking force by adjusting the opening of the IAT valve;

[0045] Sb300 performs 1 / 2 cylinder braking and at the same time, the braking force is infinitely adjusted by adjusting the opening of the IAT valve.

[0046] Preferably, the preset conditions for constant speed braking are: the vehicle is in a downhill condition and meets the high-power braking conditions of the engine, wherein:

[0047] The high-power braking condition is: the engine speed is greater than a manually preset high-power braking speed threshold, and the throttle opening is 0, and the vehicle speed is greater than a manually preset high-power braking speed threshold, and the boost pressure is greater than a manually preset high-power braking pressure threshold, and the water temperature is greater than a manually preset high-power braking water temperature threshold.

[0048] Preferably, the first engine target speed is expressed as follows:

[0049] n1=V / (k1×k h ×C×60)

[0050] Wherein: n1 is used to represent the first engine target speed; V is used to represent the current vehicle speed; k1 is used to represent the gearbox downshift ratio; k h Used to characterize the rear axle speed ratio; C is used to characterize the tire circumference.

[0051] Preferably, the second engine target speed is expressed as follows:

[0052] n2=V / (k2×k h ×C×60)

[0053] Among them: n2 is used to represent the target speed of the second engine; k2 is used to represent the gearbox downshift 2 gear ratio.

[0054] Preferably, the required braking force is expressed as follows:

[0055]

[0056] Among them: F T is used to characterize the required braking force; m is used to characterize the vehicle mass; g is used to characterize the acceleration of gravity; f is used to characterize the rolling resistance coefficient; C d It is used to characterize the air resistance coefficient; A is used to characterize the frontal area; ρ is used to characterize the air density; and V is used to characterize the current vehicle speed.

[0057] Preferably, the air density is 1.293 kg / m 3 .

[0058] Preferably, the constant vehicle speed range is 45km / h to 65km / h.

[0059] Compared with the prior art, the present invention has the following advantages:

[0060] 1. The present invention achieves high braking power by controlling different brake solenoid valve timings of the engine.

[0061] 2. The present invention realizes stepless control of braking power by coordinating the IAT and high-power braking, and simultaneously considers the influence of the transmission gear on the vehicle speed, and realizes a constant downhill speed by adjusting the transmission gear, engine braking and IAT opening, thereby reducing safety hazards and reducing the cost of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a schematic diagram of the integrated power chain brake control process of a specific embodiment of the present invention;

[0063] Figure 2 It is a schematic diagram of derivation of the braking force required for a vehicle in a downhill condition according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0064] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0065] like Figure 1 As shown, the integrated integrated power chain braking control method comprises the following steps:

[0066] S100. Determine whether the current vehicle meets the preset conditions for constant speed braking; then perform the following operations according to the determination result:

[0067] If the vehicle meets the preset condition for constant speed braking, S200 is executed.

[0068] If the vehicle does not meet the preset condition for constant speed braking, S100 is executed again.

[0069] S200. Determine whether the vehicle driver has a constant speed braking requirement, and then perform the following operations according to the determination result:

[0070] If the driver presses the constant speed brake switch, it is determined that the driver has a constant speed brake demand, and then S300 is executed.

[0071] If the driver does not press the constant speed brake switch, it is determined that the driver has no constant speed brake demand, and then the process returns to and re-executes S100 .

[0072] S300. Determine whether the current vehicle speed is within a preset constant vehicle speed range, and then perform the following operations according to the determination result:

[0073] If the current vehicle speed is within the constant vehicle speed range, S400 is executed.

[0074] If the current vehicle speed is not within the constant vehicle speed interval, the process returns to and re-executes S100 .

[0075] S400. Record the current vehicle speed and set the current vehicle speed as the target vehicle speed for the constant vehicle speed.

[0076] S500. Record the current vehicle speed in real time, compare the target vehicle speed of the constant vehicle speed with the current vehicle speed, and then perform the following operations according to the comparison result:

[0077] If the current vehicle speed is greater than the target vehicle speed of the constant vehicle speed and the current vehicle speed exceeds the manually preset integrated braking speed threshold, S600 is executed.

[0078] If the current vehicle speed is not greater than the constant speed target speed, or the previous vehicle speed does not exceed the integrated braking speed threshold, it is determined that braking is not required at present.

[0079] S600. Prioritize the gear shift calculation of the transmission, and perform braking calculation based on the current engine speed and the current transmission gear position and execute the integrated braking sub-process.

[0080] It should be noted that the integrated braking sub-process specifically includes the following steps:

[0081] Sa100. Calculate the first transmission target gear position and the first engine target speed after the current transmission gear position is downgraded by one gear.

[0082] Sa200. Determine whether the first engine target speed exceeds the manually preset engine protection speed threshold, and then perform the following operations according to the determination result:

[0083] If the first target engine speed exceeds the engine protection speed threshold, the maximum cylinder number braking of the engine is turned on, and the maximum braking force is maintained for braking, and then S500 is executed.

[0084] If the first target engine speed does not exceed the engine protection speed threshold, Sa300 is executed.

[0085] Sa300. Determine whether the required braking force after the gearbox shifts down one gear exceeds the maximum braking force of the engine, and then perform the following operations based on the judgment result:

[0086] If the braking force required after the transmission gear is downshifted by one gear exceeds the maximum braking force of the engine, step Sa400 is executed.

[0087] If the required braking force after the transmission gear is downshifted by one gear does not exceed the maximum braking force of the engine, the transmission will prioritize downshifting by one gear and then execute the braking sub-processes with different numbers of cylinders.

[0088] Sa400. Calculate the second transmission target gear position and the second engine target speed after the current transmission gear position is downgraded by two gears.

[0089] Sa500. Determine whether the second engine target speed exceeds the engine protection speed threshold, and then perform the following operations according to the determination result:

[0090] If the second target engine speed exceeds the engine protection speed threshold, the maximum cylinder number braking of the engine is turned on, and the maximum braking force is maintained for braking, and then S500 is executed.

[0091] If the second target engine speed does not exceed the engine protection speed threshold, Sa600 is executed.

[0092] Sa600. Determine whether the required braking force after the transmission gear is downshifted by two gears exceeds the maximum braking force of the engine, and then perform the following operations based on the judgment result:

[0093] If the braking force required after the transmission gear is downshifted by two gears exceeds the maximum braking force of the engine, the maximum cylinder number braking of the engine is turned on and the maximum braking force is maintained for braking, and then S500 is executed.

[0094] If the required braking force after the transmission gear is downshifted by two gears does not exceed the maximum braking force of the engine, the transmission will prioritize downshifting by two gears and then execute the braking sub-processes with different numbers of cylinders.

[0095] It should be noted that the braking sub-process with different cylinder numbers specifically includes the following steps:

[0096] Sb100. Determine whether the current required braking force requires maximum cylinder braking, and then perform the following operations based on the determination result:

[0097] If the currently required braking force exceeds the maximum braking force of the engine itself, it is determined that maximum cylinder braking is required, and then Sb200 is executed.

[0098] If the currently required braking force does not exceed the maximum braking force of the engine itself, it is determined that maximum cylinder braking is not required, and Sb300 is then executed.

[0099] Sb200 performs maximum cylinder braking and infinitely adjusts the braking force by adjusting the opening of the IAT valve.

[0100] Sb300 performs 1 / 2 cylinder braking and at the same time, the braking force is infinitely adjusted by adjusting the opening of the IAT valve.

[0101] It should be further explained that the braking force of the engine itself is measured through experiments under conditions of different speeds and different numbers of cylinders.

[0102] It should be noted that the preset conditions for constant speed braking are: the vehicle is in a downhill condition and meets the high-power braking conditions of the engine, where:

[0103] The high-power braking conditions are: the engine speed is greater than the manually preset high-power braking speed threshold, the throttle opening is 0, the vehicle speed is greater than the manually preset high-power braking speed threshold, the boost pressure is greater than the manually preset high-power braking pressure threshold, and the water temperature is greater than the manually preset high-power braking water temperature threshold.

[0104] It should be further explained that the high-power brake pressure threshold and the high-power brake water temperature threshold are respectively formulated according to the actual reliability requirements of engine components; the high-power brake speed threshold and the high-power brake vehicle speed threshold are respectively formulated according to the engine brake hardware working characteristic parameters.

[0105] It should be noted that the first engine target speed is expressed as follows:

[0106] n1=V / (k1×k h ×C×60) (1)

[0107] Where: n1 is used to represent the first engine target speed; V is used to represent the current vehicle speed; k1 is used to represent the gearbox downshift ratio; k h Used to characterize the rear axle speed ratio; C is used to characterize the tire circumference.

[0108] It should be noted that the second engine target speed is expressed as follows:

[0109] n2=V / (k2×k h ×C×60) (2)

[0110] Among them: n2 is used to represent the second engine target speed; k2 is used to represent the gearbox downshift 2 gear ratio.

[0111] It should be noted that the required braking force is expressed as follows:

[0112]

[0113] Among them: F T It is used to characterize the required braking force; m is used to characterize the vehicle mass; g is used to characterize the acceleration of gravity; f is used to characterize the rolling resistance coefficient; C d It is used to characterize the air resistance coefficient; A is used to characterize the frontal area; ρ is used to characterize the air density; and V is used to characterize the current vehicle speed.

[0114] like Figure 2 As shown, it needs to be further explained that the required braking force is derived from the vehicle acceleration formula; the acceleration of the vehicle is expressed by formula 4:

[0115]

[0116] Wherein: a is used to characterize the acceleration of the vehicle; F W Used to characterize the air resistance of a vehicle; F f It is used to characterize the rolling resistance of the vehicle; θ is used to characterize the angle of the downhill slope.

[0117] The air resistance is expressed as follows:

[0118]

[0119] The rolling resistance is expressed as follows:

[0120] F f =fmg×cosθ (6)

[0121] Substituting equation 5 and equation 6 into equation 4, we can get equation 7:

[0122]

[0123] Among them: According to my country's highway design specifications, the slope of general roads is relatively small, so sinθ≈tanθ=i, cosθ=1; i is used to represent the slope of the vehicle's downward slope.

[0124] When the vehicle is going downhill at a constant speed, let the acceleration be equal to 0, and the required braking force formula of Formula 3 can be derived from Formula 7.

[0125] It should be further explained that the air resistance coefficient is determined through experiments; the frontal area is related to the windward surface of the entire vehicle; and the rolling resistance coefficient is determined through actual road use tests.

[0126] In this specific embodiment, the air density is 1.293 kg / m 3 .

[0127] In this specific embodiment, the constant vehicle speed range is 45km / h to 65km / h.

[0128] In this specific embodiment, the engine protection speed threshold is measured based on an engine reliability test.

[0129] In this specific embodiment, the maximum cylinder number braking is 6-cylinder braking, and the 1 / 2 cylinder number braking is 3-cylinder braking.

[0130] It should be further explained that the present invention is also applicable to a 4-cylinder engine.

[0131] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0132] The disclosed embodiments are described above to enable any person skilled in the art to implement or use the present invention. Various modifications of these embodiments are obvious to those skilled in the art, and the general principles defined herein may also be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0133] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0134] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An integrated power chain braking control method, characterized in that: The following steps are involved: S100. Determine whether the current vehicle meets the preset conditions for constant speed braking; then perform the following operations according to the determination result: If the vehicle meets the preset condition of constant speed braking, execute S200; If the vehicle does not meet the preset condition for constant speed braking, S100 is executed again; S200. Determine whether the vehicle driver has a constant speed braking requirement, and then perform the following operations according to the determination result: If the driver presses the constant speed brake switch, it is determined that the driver has a constant speed brake demand, and then S300 is executed; If the driver does not press the constant speed brake switch, it is determined that the driver has no constant speed brake demand, and then the process returns to and re-executes S100; S300. Determine whether the current vehicle speed is within a preset constant vehicle speed range, and then perform the following operations according to the determination result: If the current vehicle speed is within the constant vehicle speed range, execute S400; If the current vehicle speed is not within the constant vehicle speed interval, return to and re-execute S100; S400. Record the current vehicle speed and set the current vehicle speed as the target vehicle speed for constant vehicle speed; S500. Record the current vehicle speed in real time, and compare the constant vehicle speed target with the current vehicle speed, and then perform the following operations according to the comparison result: If the current vehicle speed is greater than the target vehicle speed of the constant vehicle speed, and the current vehicle speed exceeds the manually preset integrated braking vehicle speed threshold, then S600 is executed; If the current vehicle speed is not greater than the target vehicle speed of the constant vehicle speed, or the previous vehicle speed does not exceed the integrated braking vehicle speed threshold, it is determined that braking is not required at present; S600. Prioritize the gear shift calculation of the transmission, and perform braking calculation based on the current engine speed and the current transmission gear position and execute the integrated braking sub-process.

2. The integrated power chain braking control method according to claim 1, characterized in that: The integrated braking sub-process specifically comprises the following steps: Sa100. Calculate the first gearbox target gear position and the first engine target speed after the current gearbox gear is downgraded by one gear; Sa200. Determine whether the first engine target speed exceeds the manually preset engine protection speed threshold, and then perform the following operations according to the determination result: If the first target engine speed exceeds the engine protection speed threshold, the maximum cylinder number braking of the engine is turned on, and the maximum braking force is maintained for braking, and then S500 is executed; If the first engine target speed does not exceed the engine protection speed threshold, executing Sa300; Sa300. Determine whether the required braking force after the gearbox is downshifted by one gear exceeds the maximum braking force of the engine, and then perform the following operations according to the determination result: If the required braking force after the gearbox is downshifted by one gear exceeds the maximum braking force of the engine, executing step Sa400; If the required braking force after the gearbox is downshifted by one gear does not exceed the maximum braking force of the engine, the gearbox is downshifted by one gear first, and then the braking sub-process with different cylinder numbers is executed; Sa400. Calculate the second gearbox target gear and the second engine target speed after the current gearbox gear is downgraded by two gears; Sa500. Determine whether the second engine target speed exceeds the engine protection speed threshold, and then perform the following operations according to the determination result: If the second engine target speed exceeds the engine protection speed threshold, the maximum cylinder number braking of the engine is turned on, and the maximum braking force is maintained for braking, and then S500 is executed; If the second engine target speed does not exceed the engine protection speed threshold, executing Sa600; Sa600. Determine whether the required braking force after the gearbox is downshifted by two gears exceeds the maximum braking force of the engine, and then perform the following operations according to the determination result: If the required braking force after the gearbox is downshifted by two gears exceeds the maximum braking force of the engine, the maximum cylinder number braking of the engine is turned on, and the maximum braking force is maintained for braking, and then S500 is executed; If the required braking force after the transmission gear is downshifted by two gears does not exceed the maximum braking force of the engine, the transmission will be downshifted by two gears first, and then the braking sub-process with different cylinder numbers will be executed.

3. The integrated power chain brake control method according to claim 2, characterized in that: The braking sub-process with different cylinder numbers specifically comprises the following steps: Sb100. Determine whether the current required braking force requires maximum cylinder braking, and then perform the following operations according to the determination result: If the current required braking force exceeds the maximum braking force of the engine itself, it is determined that maximum cylinder braking is required, and then Sb200 is executed; If the current required braking force does not exceed the maximum braking force of the engine itself, it is determined that maximum cylinder braking is not required, and then Sb300 is executed; Sb200. Perform maximum cylinder braking and stepless adjustment of braking force by adjusting the opening of the IAT valve; Sb300 performs 1 / 2 cylinder braking and at the same time, the braking force is infinitely adjusted by adjusting the opening of the IAT valve.

4. The integrated power chain brake control method according to claim 3, characterized in that: The preset conditions for constant speed braking are: the vehicle is in a downhill condition and meets the high-power braking conditions of the engine, where: The high-power braking condition is: the engine speed is greater than a manually preset high-power braking speed threshold, and the throttle opening is 0, and the vehicle speed is greater than a manually preset high-power braking speed threshold, and the boost pressure is greater than a manually preset high-power braking pressure threshold, and the water temperature is greater than a manually preset high-power braking water temperature threshold.

5. The integrated power chain brake control method according to claim 4, characterized in that: The first engine target speed is expressed as follows: n1=V / (k1×k h ×C×60) Wherein: n1 is used to represent the first engine target speed; V is used to represent the current vehicle speed; k1 is used to represent the gearbox downshift ratio; k h Used to characterize the rear axle speed ratio; C is used to characterize the tire circumference.

6. The integrated power chain brake control method according to claim 5, characterized in that: The target speed of the second engine is expressed as follows: n2=V / (k2×k h ×C×60) Among them: n2 is used to represent the target speed of the second engine; k2 is used to represent the gearbox downshift 2 gear ratio.

7. The integrated power chain brake control method according to claim 6, characterized in that: The required braking force is expressed as follows: Among them: F T is used to characterize the required braking force; m is used to characterize the vehicle mass; g is used to characterize the acceleration of gravity; f is used to characterize the rolling resistance coefficient; C d It is used to characterize the air resistance coefficient; A is used to characterize the frontal area; ρ is used to characterize the air density; and V is used to characterize the current vehicle speed.

8. The integrated power chain brake control method according to claim 7, characterized in that: The value of the air density is 1.293 kg / m3.

9. The integrated power chain brake control method according to claim 8, characterized in that: The constant vehicle speed range is 45km / h to 65km / h.

Images