Design method for minimum intake preheating power of on-way heat dissipation flame glow plug diesel engine

Abstract

The invention provides a minimum intake preheating power design method for an on-way heat dissipation flame glow plug diesel engine, which comprises the following steps of: firstly, constructing a diesel engine intake energy conservation equation set considering on-way heat dissipation of an intake pipeline; then, a triple data set composed of the atmospheric environment temperature, the air inlet pressure value and the corresponding minimum air inlet preheating power is obtained according to the diesel engine air inlet energy conservation equation set, and finally, a first Map graph of the minimum air inlet preheating power changing along with the diesel engine rotating speed and the atmospheric environment temperature is obtained according to the triple data set; according to the second Map, the minimum air inlet preheating power changes along with the rotating speed of the diesel engine and the altitude; therefore, the on-way heat dissipation loss of the intake manifold and the intake duct is considered, so that the intake preheating power of the diesel engine can be autonomously regulated and controlled along with the change of the environment temperature, and the cold starting performance of the diesel engine can be improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of diesel engine, and particularly relates to a method for designing minimum intake preheating power of a flame preheating plug diesel engine. BACKGROUND

[0002] The diesel engine has strong power output, high thermal efficiency, good reliability, stable operation, and does not have the cost problem, safety problem and waste environmental problem existing in gas engine, battery engine and hydrogen engine. Therefore, it is still the primary power source of military vehicles, special vehicles and various types of commercial engineering power machinery. However, under extreme environmental conditions such as an altitude of 5000m or a temperature of-50℃, the air density inhaled by the diesel engine is small and the temperature is low, so that the intake temperature of the diesel engine is reduced, the atomization is difficult, the oil-gas mixing is poor, the compression end heat state in the cylinder is close to the critical ignition condition of diesel spray, which leads to a greatly prolonged ignition delay period or even misfire. At the same time, due to the increase in viscosity at low temperature, the condensation flowability of diesel oil decreases, the friction resistance of the engine increases, and the starting torque increases greatly. In addition, the battery power is greatly reduced under low temperature conditions, and the starting motor is difficult to play an ideal drag performance. The above problems seriously affect the work of the diesel engine under extreme environment. Research shows that the cold start of the diesel engine under the condition of low temperature below-0℃ and high altitude above 3000m is still an important problem to be solved.

[0003] Preheating the intake air of a diesel engine and then entering the engine after the atmospheric temperature is raised can effectively improve the compression end temperature in the cylinder, which is an important means to solve the poor cold start performance of diesel engines in low temperature or high altitude environments. Since the exhaust turbocharger does not work during the cold start stage, only the fresh air heated by the intake air preheating device directly enters the cylinder of the diesel engine. The preheating power (or oil supply rate) of the previous diesel engine flame intake preheating device is constant, and the intake air preheating power does not change with the change of speed, atmospheric temperature and atmospheric pressure. The intake air preheating power (or oil supply rate) is determined in the working condition with the largest demand for intake air preheating power, while in other working conditions, the preheating power is surplus. The intake air preheating power of the diesel engine using the existing intake air preheating design method does not change with the change of speed, and does not have environmental adaptability with the change of atmospheric temperature and atmospheric pressure. At the same time, the heat dissipation of the engine intake pipeline also affects the actual air flow of the diesel engine, and then affects the working performance of the engine in extreme environment. In addition to the along-the-way loss of the intake manifold, the high-temperature intake air after preheating of the engine also has heat loss in each intake port before entering the cylinder. The intake stroke of a four-stroke engine accounts for 1 / 4 of the entire cycle, and only the high-temperature intake air after preheating can enter the cylinder in time during the intake stroke stage, while the high-temperature intake air can only reside in the intake port during the remaining 3 / 4 cycle. At this time, the outside coolant temperature is relatively low, which can have a "cooling" effect on the high-temperature intake air in the intake port, so this part of the heat loss cannot be ignored. In order to maintain the air temperature in the intake port to meet the minimum intake air temperature requirement of the engine, the loss power of this part needs to be supplemented. Although the minimum intake air preheating power design method of the low-temperature adaptive diesel engine is summarized in patent CN114139356A, the influence of engine along-the-way heat loss on the minimum intake air preheating power is not considered. Research shows that when the environmental temperature is lower than-30℃, the flame intake preheating fails due to heat loss of the intake pipeline.

[0004] In summary, the current intake air preheating design method does not consider the along-the-way heat loss of the intake pipeline during the intake air preheating process of the diesel engine, and the environmental adaptability of the minimum intake air preheating power of the diesel engine flame preheating plug needs to be further improved. In order to improve the cold start performance of the diesel engine in extreme environments (low temperature and high altitude environment), a new along-the-way heat loss adaptive diesel engine minimum intake air preheating power design method is needed. SUMMARY

[0005] To solve the above problems, the present application provides a along-the-way heat loss flame preheating plug diesel engine minimum intake air preheating power design method, which considers the along-the-way heat loss of the intake pipeline and the influence of intake port heating, and can adaptively adjust the minimum intake air preheating power of the intake air preheating device during the starting process of the diesel engine with the change of the speed, the initial temperature of the air and the altitude, which is beneficial to the improvement of the environmental adaptability of the diesel engine.

[0006] A method for designing minimum intake preheating power of a diesel engine preheated by a flame along a heat dissipation path, comprising the following steps:

[0007] Constructing a diesel engine intake energy conservation equation set considering heat dissipation along an intake pipeline, wherein the diesel engine intake energy conservation equation set is a mapping relationship between atmospheric environment temperature T air , intake pressure P in and minimum intake preheating power;

[0008] Setting different values of atmospheric environment temperature T air and intake pressure P in in the diesel engine intake energy conservation equation set to obtain minimum intake preheating power corresponding to different values; meanwhile, taking each set of values of atmospheric environment temperature T air , intake pressure P in and corresponding minimum intake preheating power as a three-element group data, and all three-element group data constitute a three-element group data set;

[0009] Importing the three-element group data set into a drawing simulation software, and outputting, by the drawing simulation software, a first Map graph of minimum intake preheating power following diesel engine speed n and atmospheric environment temperature T air variation, and a second Map graph of minimum intake preheating power following diesel engine speed n and altitude variation; wherein the diesel engine speed n and the intake pressure P in have a mapping relationship, and the altitude and the atmospheric environment temperature T air also have a mapping relationship.

[0010] Further, when atmospheric environment temperature T air ≥-20°, the diesel engine intake energy conservation equation set is as follows:

[0011]

[0012] Wherein m air is diesel engine intake flow, c p is specific heat at constant pressure of mixed gas, T1 is intake manifold starting temperature, C f is friction coefficient, Pr is Prandtl number, A w1 is intake manifold wall surface area, A D is intake manifold cross-sectional area, T intake_i is temperature of the i-th section of intake manifold, k1 is total section number obtained by dividing the intake manifold according to differential principle, A d is intake port flow-through cross-sectional area, A w2 is intake port contact surface area, T in-min is diesel engine minimum intake temperature, T inlet_jTj is the temperature of the jth intake passage, k2 is the total number of sections obtained by dividing the intake passage according to the differential principle, m air c p (T1-T air ) represents the minimum intake preheating power.

[0013] Further, the temperature T intake_i of the ith intake manifold is calculated as follows:

[0014]

[0015] where T2 is the terminal temperature of the intake manifold after the gas is cooled along the intake manifold, T2 is also the starting temperature of the intake passage, L is the length of the intake manifold, L i = i-AL1, AL1 is the set length of the intake manifold microelement, and AL = L / k1.

[0016] Further, the temperature T inlet_j of the jth intake passage is calculated as follows:

[0017]

[0018] where T2 is the terminal temperature of the intake manifold after the gas is cooled along the intake manifold, T2 is also the starting temperature of the intake passage, l is the length of the intake passage, l j = j-AL2, AL2 is the set length of the intake passage microelement, and AL2 = l / k2.

[0019] Further, when the atmospheric environment temperature T air < -20°, the diesel engine intake energy conservation equation set is as follows:

[0020]

[0021] where m air is the diesel engine intake flow rate, c p is the specific heat of the mixture at constant pressure, T1 is the starting temperature of the intake manifold, C f is the friction coefficient, Pr is the Prandtl number, A w1 is the wall surface area of the intake manifold, A D is the cross-sectional area of the intake manifold, T intake_i is the temperature of the ith intake manifold, k1 is the total number of sections obtained by dividing the intake manifold according to the differential principle, A d is the flow cross-sectional area of the intake passage, A w2 is the contact surface area of the intake passage, T in-min is the minimum intake temperature of the diesel engine, T inlet_j is the temperature of the jth intake passage, k2 is the total number of sections obtained by dividing the intake passage according to the differential principle, mair c p (T1-T air ) represents the minimum intake preheating power.

[0022] Further, the temperature T intake_i of the i-th section intake manifold is calculated as follows:

[0023]

[0024] wherein T2 is the terminal temperature of the intake manifold after heat dissipation along the path, T2 is also the starting temperature of the intake port, L is the length of the intake manifold, L i = i*DeltaL1, DeltaL1 is the set length of the intake manifold microelement, DeltaL = L / k1.

[0025] Further, the temperature T inlet_j of the j-th section intake port is calculated as follows:

[0026]

[0027] wherein T2 is the terminal temperature of the intake manifold after heat dissipation along the path, T2 is also the starting temperature of the intake port, l is the length of the intake port, l j = j*DeltaL2, DeltaL2 is the set length of the intake port microelement, DeltaL2 = l / k2.

[0028] Further, the mapping relationship between the diesel engine speed n and the intake pressure P in is as follows:

[0029]

[0030] wherein tau is the number of cylinders of the diesel engine, eta is the flow coefficient, R g is the gas constant, T in-min is the minimum intake temperature of the diesel engine, V h is the displacement of the diesel engine.

[0031] Further, the mapping relationship between the altitude and the atmospheric environmental temperature T air is as follows:

[0032] The atmospheric environmental temperature T air decreases by 0.6℃ on average when the altitude increases by 100 meters.

[0033] Advantages:

[0034] The present application provides a method for designing the minimum intake preheating power of a flame preheating plug diesel engine, which first constructs the diesel engine intake energy conservation equation set considering the heat dissipation along the path of the intake pipe, and then obtains the minimum intake preheating power of the diesel engine from the atmospheric environmental temperature Tair , intake pressure P in The value and the corresponding minimum intake preheating power form a ternary data set, and finally the minimum intake preheating power is obtained according to the ternary data set, the diesel engine speed n and the atmospheric environment temperature T air The first Map diagram of the change, and the second Map diagram of the minimum intake preheating power following the change of the diesel engine speed n and the altitude; therefore, the minimum intake preheating power of the intake preheating device under different environmental conditions can be determined according to the change relationship in the two Map diagrams under the given altitude, environmental temperature and the like conditions; it can be seen that the heat loss along the path of the intake manifold and the intake passage is considered in the application, so that the diesel engine intake preheating power can be autonomously regulated with the change of the environmental temperature, which is beneficial to improve the cold start performance of the diesel engine. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 A flow chart of a method for designing the minimum intake preheating power of a diesel engine with a flame preheating plug considering heat loss along the path is provided in the application;

[0036] Figure 2 A working principle diagram of the application;

[0037] Figure 3 A calculation principle diagram of the application;

[0038] Figure 4 A second MAP diagram of the minimum intake preheating power following the change of the altitude;

[0039] Figure 5 A first MAP diagram of the minimum intake preheating power following the change of the atmospheric temperature;

[0040] Figure 6 Engine intake process node temperatures under different altitudes under -20 DEG C atmosphere;

[0041] Figure 7 Engine intake process node temperatures under different atmospheric temperatures under 0 m altitude. DETAILED DESCRIPTION

[0042] In order for the personnel in the technical field to better understand the scheme of the application, the technical scheme in the embodiments of the application will be clearly and completely described below in combination with the drawings in the embodiments of the application.

[0043] As Figure 1 shown, a method for designing the minimum intake preheating power of a diesel engine with a flame preheating plug considering heat loss along the path, comprising the following steps:

[0044] S1: constructing a diesel engine intake energy conservation equation set considering heat loss along the path of the intake pipeline, wherein the diesel engine intake energy conservation equation set is a diesel engine intake energy conservation equation set considering the atmospheric environment temperature Tair Intake pressure P in Mapping relationship between the minimum intake preheating power;

[0045] S2: represents the ambient temperature T in the diesel engine intake energy conservation equations. air Intake pressure P in By setting different values, the minimum intake preheating power corresponding to each value is obtained; at the same time, the ambient atmospheric temperature T for each group is... air Intake pressure P in Each value and its corresponding minimum intake preheating power are taken as a triplet data point, and all triplet data points constitute a triplet dataset.

[0046] S3: Import the triplet dataset into the plotting simulation software. The plotting simulation software will output the minimum intake preheating power based on the diesel engine speed n and the ambient temperature T. air The first map shows the changes, and the second map shows the minimum intake preheating power varying with diesel engine speed n and altitude; where diesel engine speed n is related to intake pressure P. in There is a mapping relationship between altitude and atmospheric ambient temperature T. air There is also a mapping relationship between them.

[0047] The following details the process of constructing the diesel engine intake energy conservation equations.

[0048] refer to Figures 2-3 After being preheated by the flame, the hot air flows from the intake manifold to the cylinder through the intake manifold and intake passage. When the ambient temperature is low, the preheated hot air dissipates heat to the outside atmosphere through the intake manifold wall and to the diesel engine coolant through the intake passage wall. The temperatures at each stage of the intake process are defined as follows: T air T1 is the ambient temperature; T2 is the preheated temperature after being heated by the glow plug, i.e., the starting temperature of the intake manifold; T3 is the ending temperature of the intake manifold after the high-temperature gas dissipates heat along the intake manifold, i.e., the starting temperature of the intake duct; T4 is the ambient temperature. in-min This is the engine's minimum intake air temperature. Additionally, when the engine is started from a standstill via the starter motor, the minimum intake air temperature is defined as T. in-min-start At this point, the engine cylinder contains only fresh air, and the lowest intake air temperature is the compression start temperature (T). in-min-start =T 1-min After a diesel engine successfully starts at the injection start speed, its speed gradually increases to idle speed. This process is defined as the engine's ramp-up period, and the minimum intake air temperature during the ramp-up period is defined as T. in-min-rampDuring the acceleration phase, high-temperature residual exhaust gas from successful ignition remains in the cylinder. In the next cycle, this gas mixes with the fresh charge and participates in combustion, contributing to the power output. This portion of exhaust gas also heats the subsequent fresh air. Therefore, the minimum intake air temperature T of a diesel engine... in-min A piecewise function of engine speed: At the injection start speed, the lowest intake air temperature is the compression start temperature T. in-min =T in-min-start =T 1-min During the acceleration phase, residual exhaust gas in the cylinder heats the intake air, with a minimum intake air temperature T. in-min =T in-min-ramp .

[0049] Step 1: Based on the diesel engine compression ratio ε, adiabatic index k, lower heating value of fuel LHV, and specific heat of the mixture at constant volume c... v The calculated start-up speed and the minimum intake air temperature of the diesel engine during the acceleration period are shown in Equation (1).

[0050]

[0051] Step Two: Establish the intake manifold heat transfer model. In this embodiment, we are working on a 6V diesel engine, which has two rows of cylinders. For simplified calculations, the interior of the intake manifold on one side can be approximated as a cuboid with dimensions (a×b×h) of 570mm×110mm×60mm. The model establishment process is as follows:

[0052] Step 2-1: The heat exchange process on the wall of a single-sided intake manifold can be represented by the following formula:

[0053] P w1 =h intake ·A w1 ·(T intake -T w1 (2)

[0054] In the formula, P w1 For the heat dissipation power of the intake manifold wall, A w1 T is the surface area of ​​the intake manifold wall. w1 The intake manifold wall temperature can be approximated as the ambient air temperature T. air h intake The wall-to-air heat transfer coefficient is given.

[0055] Step 2-2: First, calculate the wall-to-air heat transfer coefficient, which is calculated as follows:

[0056]

[0057] In this formula, ρ intake For air density, u intake c is the intake airflow velocity. pThe specific heat at constant pressure of the mixture gas. The friction coefficient C f The flow state of the fluid in the intake manifold is related to the Reynolds number Re and the roughness of the pipe wall. The engine intake flow rate u f The Reynolds number is calculated according to the equivalent diameter D of the intake manifold and the air kinematic viscosity v in the intake manifold, and the change with the rotational speed is about 2-8.5 m / s:

[0058]

[0059] The calculated air Re D in the intake manifold is greater than 4000, which is in a turbulent flow state. The C f can be calculated according to the Nikuradse formula.

[0060] Step 2-3: Calculate the air flow rate u f in the single-sided intake manifold, and the calculation formula is as follows:

[0061]

[0062] A D is the cross-sectional area of the intake manifold, and the approximate cross-sectional area is uniform and equal; p f is the air density, m air is the engine intake flow rate, which is calculated based on the preheated state of the intake air, and the intake flow rate in the single-sided intake manifold should be half of the engine intake flow rate:

[0063]

[0064] n is the engine speed, τ is the number of cylinders, η is the flow coefficient, P in is the intake pressure, and R g is the gas constant.

[0065] Step 2-4: The heat transfer coefficient expression in the intake manifold can be obtained by combining formula (3), formula (5), and formula (6):

[0066]

[0067] Step 2-5: Substituting formula (5) and formula (6) can obtain the air flow rate u f in the single-sided intake manifold, which changes with the engine speed n and the temperature T intake in the intake manifold as follows:

[0068]

[0069] Step 2-6: Calculate the instantaneous intake temperature T intake at position x in the intake manifold, which can be linearly represented as:

[0070]

[0071] In the formula, T1 is the starting temperature of the intake manifold; T2 is the ending temperature of the intake manifold after the high-temperature gas dissipates heat along the intake manifold.

[0072] Steps 2-7: According to equation (9), considering heat dissipation, the temperature inside the intake manifold gradually decreases over time, with a range of [T1, T2], and the heat dissipation power P w1 Similarly, it changes continuously over time. From equation (8), it can be seen that the instantaneous air velocity in the intake manifold at the same rotational speed is only related to the temperature inside the manifold. To simplify the calculation, based on the differential principle, the airflow in the intake manifold on one side is divided into k equal calculation segments according to time. The temperature of each segment's micro-element is approximately equal, therefore the velocity is also equal. The temperature inside the intake manifold can be expressed as:

[0073]

[0074] In the formula, T2 is the temperature at the end of the intake manifold after the gas dissipates heat along the intake manifold, and T2 is also the temperature at the beginning of the intake duct; L is the length of the intake manifold. i =i·ΔL1, where ΔL1 is the set length of the intake manifold micro-element, and ΔL = L / k1.

[0075] Therefore, the formula for calculating the heat dissipation power of a single-sided intake manifold can be expressed as:

[0076]

[0077] Step 3: Establish the intake duct heat transfer model. The model establishment process is as follows:

[0078] For the 6V engine under study, the diesel engine does not use a coolant heater when the ambient temperature is above -20℃. Therefore, in environments above -20℃, the coolant temperature is equivalent to the ambient temperature, which has a "cooling" effect on the air in the intake manifold. The intake preheating power needs to compensate for the heat transfer losses of the air in the intake manifold. When the ambient temperature is below -20℃, the coolant heater is first used to raise the coolant temperature to 60℃ before starting the engine, and then the intake preheating is used to start the engine. Therefore, in environments below -20℃, the coolant has a certain "heating" effect on the air in the intake manifold. Therefore, the heat transfer losses of the air in the intake manifold need to be calculated separately with -20℃ as the boundary.

[0079] Step 3-1: Heat transfer loss in the intake manifold is analogous to the heat transfer model of the intake manifold. Since the air in the intake manifold exchanges heat with the external cooling water, it is an air-water heat transfer. Compared with the air-air heat transfer in the intake manifold, the heat transfer coefficient is larger, and the air in the intake manifold stays in the intake manifold for a long time before entering the cylinder, which increases the heat transfer.

[0080] For simplification, the heat transfer coefficient in the intake duct is taken as 1.5 times that in the intake manifold.

[0081]

[0082] Step 3-2, the mathematical expression of the heat exchange in the intake duct is obtained as:

[0083]

[0084] A d is the flow area of the intake duct, A w2 is the contact surface area of the intake duct, T inlet_i is the air temperature in the intake duct, which is expressed as:

[0085]

[0086] where T2 is the terminal temperature of the intake manifold after heat dissipation along the way, T2 is also the starting temperature of the intake duct, l is the length of the intake duct, l j = j·ΔL2, ΔL2 is the set length of the intake duct microelement, ΔL2 = l / k2.

[0087] Step four: 6V diesel engine with two rows of symmetrical arrangement, single side 3 cylinders, each cylinder 2 intake ducts, so single row needs to consider the heat loss of 6 sections of intake ducts.

[0088] Step 4-1: The minimum intake preheating power of the diesel engine is equal to the sum of the heat loss power of the two rows of intake manifolds along the way, the heat loss of the intake ducts and the ideal intake preheating power of the engine, which satisfies the following equation:

[0089]

[0090] Step 4-2: When the atmospheric temperature is above -20℃, the temperature in the intake duct is directly exchanged with the environment, and the atmospheric temperature above -20℃ is obtained by substituting equations (11) and (13) into equation (15). When the atmospheric temperature is below -20℃, the air in the intake duct exchanges heat with 60℃ (333.15K) cooling water, and the intake energy conservation equation is shown in equation (17).

[0091]

[0092] In the above equation, the flow rate u f is positively correlated with the engine speed and can be considered as a known quantity. Thus, by inputting the parameters of the diesel engine and the intake pipeline, as well as the physical parameters of air under different environmental conditions, adjusting the atmospheric temperature T air and the intake pressure P in , the equations Figure 4 andFigure 5 The minimum preheating power of the flame preheating device of the diesel engine considering the heat dissipation along the intake pipeline is shown to follow the diesel engine speed n, the atmospheric environment temperature T air The first Map chart of variation and the second Map chart of minimum intake preheating power following the diesel engine speed n and the altitude variation are changed, so that the design of the minimum intake preheating power of the diesel engine considering the heat dissipation along the intake pipeline is completed.

[0093] In the embodiment, the basic parameters of the diesel engine are as follows: the start injection speed of the diesel engine is 200, 250, 300 rpm, the ramp speed is from 200 rpm to 800 rpm, the compression ratio ε is 13.5, the single cylinder displacement V h is 2L, the charge efficiency η is 0.7, the low heat value of fuel LHV is 43kJ / kg, the cylinder number is 2X3; the length of the single side intake manifold is 570mm, the equivalent diameter is 77.6mm; the minimum intake preheating power under different altitudes and different ambient temperatures is calculated when the intake length is 130mm and the diameter is 40mm, as shown in Figure 6 and Figure 7 The boundary distribution of the intake temperature of the 6V132 diesel engine under typical conditions (different altitudes under-20℃ / different atmospheric temperatures under 0m altitude) is calculated, as shown in Figure 6 and Figure 7 .

[0094] Therefore, the minimum intake preheating power design method of the heat dissipation flame preheating plug diesel engine is provided, the heat dissipation along the intake pipeline is considered, the calculation method of the heat dissipation of the diesel engine intake pipeline is given, and the method of adaptively adjusting the minimum intake preheating power of the intake preheating device according to the environmental conditions (altitude, ambient temperature) is proposed, which is beneficial to improve the cold start performance of the diesel engine.

[0095] Of course, the present application can have other various embodiments, and those skilled in the art can certainly make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should belong to the protection scope of the claims attached to the present application.

Claims

1. A method for designing the minimum intake preheating power of a diesel engine with a friction-dissipating flame preheating plug, characterized in that, Includes the following steps: A set of conservation equations for diesel engine intake energy, considering heat dissipation along the intake manifold, is constructed. The conservation equations for diesel engine intake energy are given by the ambient temperature T. air Intake pressure P in Mapping relationship between the minimum intake preheating power; The atmospheric ambient temperature T in the diesel engine intake energy conservation equations. air Intake pressure P in By setting different values, the minimum intake preheating power corresponding to each value is obtained; at the same time, the ambient atmospheric temperature T for each group is... air Intake pressure P in Each value and its corresponding minimum intake preheating power are taken as a triplet data point, and all triplet data points constitute a triplet dataset. Import the triplet dataset into the plotting simulation software. The plotting simulation software will output the minimum intake preheating power based on the diesel engine speed n and the ambient temperature T. air The first map shows the changes, and the second map shows the minimum intake preheating power varying with diesel engine speed n and altitude; where diesel engine speed n is related to intake pressure P. in There is a mapping relationship between altitude and atmospheric ambient temperature T. air There is also a mapping relationship between them.

2. The design method for minimum intake preheating power of a diesel engine with a friction-dissipating flame preheating plug as described in claim 1, characterized in that, When the ambient temperature T air When the temperature is ≥-20°, the energy conservation equations for the diesel engine intake are as follows: Where, m air c is the intake air flow rate of the diesel engine. p The specific heat at constant pressure of the gas mixture is given, T1 is the intake manifold inlet temperature, and C is the temperature at which the gas mixture begins to rise. f Where is the coefficient of friction, Pr is the Prandtl number, and A is the coefficient of friction. w1 A is the surface area of ​​the intake manifold wall. D T is the cross-sectional area of ​​the intake manifold. intake_i Let A be the temperature of the i-th intake manifold segment, k1 be the total number of segments obtained by dividing the intake manifold according to the differential principle, and A be the temperature of the i-th intake manifold segment. d A is the cross-sectional area of ​​the air intake passage. w2 T represents the contact surface area of ​​the intake duct. in-min T represents the lowest intake air temperature for a diesel engine. inlet_j Let k1 be the temperature of the j-th intake segment, k2 be the total number of segments obtained by dividing the intake duct according to the differential principle, and m be the temperature of the j-th intake segment. air c p (T1-T air () indicates the minimum intake preheating power.

3. The method for designing minimum intake preheating power of a diesel engine with a friction-dissipating flame preheating plug as described in claim 2, characterized in that, The temperature T of the i-th segment of the intake manifold intake_i The calculation method is as follows: In the formula, T2 is the temperature at the end of the intake manifold after the gas dissipates heat along the intake manifold, and T2 is also the temperature at the beginning of the intake duct; L is the length of the intake manifold. i =i·ΔL1, where ΔL1 is the set length of the intake manifold micro-element, and ΔL = L / k1.

4. The method for designing minimum intake preheating power of a diesel engine with a friction-dissipating flame preheating plug as described in claim 2, characterized in that, The temperature T of the j-th segment of the air intake inlet_j The calculation method is as follows: Where T2 is the temperature at the end of the intake manifold after the gas dissipates heat along its path, and T2 is also the temperature at the beginning of the intake duct; l is the length of the intake duct. j =j·ΔL2, where ΔL2 is the set length of the intake duct micro-element, ΔL2=l / k2.

5. The method for designing minimum intake preheating power of a diesel engine with a friction-dissipating flame preheating plug as described in claim 1, characterized in that, When the ambient temperature T air At temperatures below -20°C, the energy conservation equations for the diesel engine intake are as follows: Where, m air c is the intake air flow rate of the diesel engine. p The specific heat at constant pressure of the gas mixture is given, T1 is the intake manifold inlet temperature, and C is the temperature at which the gas mixture begins to rise. f Where is the coefficient of friction, Pr is the Prandtl number, and A is the coefficient of friction. w1 A is the surface area of ​​the intake manifold wall. D T is the cross-sectional area of ​​the intake manifold. intake_i Let A be the temperature of the i-th intake manifold segment, k1 be the total number of segments obtained by dividing the intake manifold according to the differential principle, and A be the temperature of the i-th intake manifold segment. d A is the cross-sectional area of ​​the air intake passage. w2 T represents the contact surface area of ​​the intake duct. in-min T represents the lowest intake air temperature for a diesel engine. inlet_j Let k1 be the temperature of the j-th intake segment, k2 be the total number of segments obtained by dividing the intake duct according to the differential principle, and m be the temperature of the j-th intake segment. air c p (T1-T air () indicates the minimum intake preheating power.

6. The method for designing minimum intake preheating power of a diesel engine with a friction-fed flame preheating plug as described in claim 5, characterized in that, The temperature T of the i-th segment of the intake manifold intake_i The calculation method is as follows: In the formula, T2 is the temperature at the end of the intake manifold after the gas dissipates heat along the intake manifold, and T2 is also the temperature at the beginning of the intake duct; L is the length of the intake manifold. i =i·ΔL1, where ΔL1 is the set length of the intake manifold micro-element, and ΔL = L / k1.

7. The method for designing minimum intake preheating power of a diesel engine with a friction-dissipating flame preheating plug as described in claim 5, characterized in that, The temperature T of the j-th segment of the air intake inlet_j The calculation method is as follows: Where T2 is the temperature at the end of the intake manifold after the gas dissipates heat along its path, and T2 is also the temperature at the beginning of the intake duct; l is the length of the intake duct. j =j·ΔL2, where ΔL2 is the set length of the intake duct micro-element, ΔL2=l / k2.

8. The design method for minimum intake preheating power of a diesel engine with a friction-dissipating flame preheating plug as described in claim 1, characterized in that, Diesel engine speed n and intake pressure P in The mapping relationships between them are as follows: Where τ is the number of cylinders in the diesel engine, η is the flow coefficient, and R g T is the gas constant. in-min V represents the minimum intake air temperature of the diesel engine. h This refers to the displacement of the diesel engine.

9. The design method for minimum intake preheating power of a diesel engine with a friction-cooled flame preheating plug as described in claim 1, characterized in that, Altitude and ambient temperature T air The mapping relationships between them are as follows: For every 100 meters increase in altitude, the atmospheric ambient temperature T... air The average temperature decreased by 0.6℃.

Images