Method for measuring and calculating power of extended-range engine

Abstract

The invention relates to the technical field of new energy vehicle type strategy logic, and particularly discloses a method for measuring and calculating the power of an extended-range engine, and the method comprises the steps: arranging a whole vehicle energy flow balance equation based on different hybrid power system energy flow structures: the power of a driving system = the output power of a range extender + the power of a power battery-the power of a high-voltage accessory; the power of the driving system is measured and calculated according to the detection result of the accelerator opening degree, and the larger the accelerator opening degree is, the larger the output torque of the driving motor is; the power of the power battery is mainly determined by looking up parameters of battery temperature, voltage and current according to a battery charging and discharging map table, and the power of the high-voltage accessory comprises the sum of the power of a PTC (Positive Temperature Coefficient), a steering motor, a DCDC (Direct Current Direct Current), an air compressor, a cooling unit and an air conditioner compressor; the working modes of the range extending system type vehicle are divided into a hybrid power mode and a pure electric mode. According to the method, the accurate engine power is reasonably measured and calculated and serves as a key factor for evaluating the performance of the whole vehicle, and the power measurement precision of the range extending system and the working efficiency of the engine are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy vehicle model strategy logic, and particularly relates to a power calculation method for a range extended engine. BACKGROUND

[0002] Energy saving, safety and emission are the three major issues of today's automobile industry. Vigorously promoting the development of new energy vehicles not only helps to reduce the consumption of oil in the transportation industry and reduce China's dependence on foreign oil, but also further realizes energy saving and emission reduction. Accurate evaluation of vehicle performance helps to improve the energy saving of the vehicle and reduce emissions, and the power of the engine is a key factor in evaluating the performance of the vehicle. There is a big difference between CNG gas-electric hybrid range extended electric vehicles working in extremely cold conditions and working in ordinary conditions. In such an environment, there is currently no mature power calculation scheme for heavy truck range extended vehicles.

[0003] Therefore, it is necessary to design a control strategy and logic algorithm for a heavy truck CNG gas-electric hybrid range extended electric vehicle to solve the problem that the existing heavy truck hybrid vehicle cannot accurately measure the engine power. SUMMARY

[0004] In view of the problems in the prior art, the purpose of the present application is to provide a power calculation method for a range extended engine, which calculates the power of the driving system, the power battery and the high-pressure auxiliary components, and combines factors such as engine friction power and system conversion efficiency to more efficiently and reasonably calculate the accurate engine power as a key factor for evaluating the performance of the vehicle.

[0005] The technical scheme adopted by the present application to solve its technical problems is: a power calculation method for a range extended engine, comprising the following steps:

[0006] S1, based on the energy flow structure of different hybrid systems, the vehicle energy flow balance equation is sorted out:

[0007] The driving system power is equal to the range extender output power plus the power battery power minus the high-pressure auxiliary component power, and the range extender output power is calculated;

[0008] S2, the driving system power is calculated by detecting the throttle opening degree, the larger the throttle opening degree, the greater the driving motor output torque; the power of the power battery is mainly determined by the parameters of the battery temperature, voltage and current according to the battery charge and discharge map table, and the power of the high-pressure auxiliary component is the sum of the powers of PTC, steering motor, DCDC, air compressor, cooling unit and air conditioning compressor;

[0009] S3, the working mode of the range extended system vehicle is divided into hybrid mode and pure electric mode;

[0010] S4, after the vehicle starts in hybrid mode, the vehicle controller starts to delay, the delay time ts, after the delay is over, start the engine, the engine enters idle operation, the vehicle controller monitors the power battery SOC and the current vehicle demand power in real time, and calculates the power of the range extending system;

[0011] S5, after the vehicle starts in pure electric mode, the vehicle mainly drives through the battery, when the battery power is low, the range extending system is automatically started to generate electricity.

[0012] Preferably, the vehicle energy flow balance equation in step S1 is used to express as:

[0013] P 驱 =P 发 ·η1+P 电 -P 辅

[0014] P 发 =(P 驱 +P 辅 +P 电 ) / η1

[0015] P 驱 =U·I

[0016]

[0017] P 辅 =P AC +P DC +P ACM +P EPS +P PTC +P TMS

[0018] Based on: P=U·I=T·n9550, mechanical power and electric power conversion comparison.

[0019] Preferably, in the formula of the vehicle energy flow balance equation:

[0020] P 发 is the engine power;

[0021] P 驱 is the driving system power, which is calculated based on the current speed, the throttle development of the driving intention;

[0022] P 电 is the power battery power, which is determined by looking up the table based on the current cell temperature and the power;

[0023] P 辅 is the vehicle high-voltage auxiliary power, which is measured in real time and compared with the rated parameters;

[0024] PAC Real-time measurement and comparison of rated parameters for high-voltage electric air conditioner power;

[0025] P DC Real-time measurement and comparison of rated parameters for the vehicle's DC-DC power;

[0026] P ACM Real-time measurement and comparison of rated parameters for high-pressure air pump power;

[0027] P EPS Real-time measurement and comparison of rated parameters for the power of the high-voltage power steering motor;

[0028] P PTC For high-voltage electric heating power, real-time measurement + comparison of rated parameters;

[0029] P TMS For thermal management unit power, real-time measurement + comparison of rated parameters;

[0030] P 增程器 -The sum of the power of all auxiliary components;

[0031] η 增程 - Operating efficiency of the range extender system;

[0032] Vehicle power requirement = P e +P 辅 .

[0033] Preferably, the specific steps for calculating the range extender system power in hybrid mode in step S4 are as follows:

[0034] ① When SOC > A, if the vehicle's required power < c, the engine enters idle mode. When b > vehicle's required power > c, the range extender system operates at the Z power point. When a > vehicle's required power > b, the range extender system operates at the X power point. When vehicle's required power > a, the range extender system operates at the V power point.

[0035] ② When B < SOC < A, if the vehicle's required power < c, the range extender system operates at the Z power point; when b > vehicle's required power > c, the range extender system operates at the N power point; when a > vehicle's required power > b, the range extender system operates at the M power point; when vehicle's required power > a, the range extender system operates at the V power point.

[0036] ③ When C < SOC < B, if the vehicle's required power < c, the range extender system operates at the N power point; when b > vehicle's required power > c, the range extender system operates at the X power point; when a > vehicle's required power > b, the range extender system operates at the M power point; when vehicle's required power > a, the range extender system operates at the V power point.

[0037] When SOC is less than C, if the vehicle demand power is less than c, the extended range system works at X power point, when b is greater than the vehicle demand power and less than c, the extended range system works at M power point, when a is greater than the vehicle demand power and less than b, the extended range system works at V power point, and when the vehicle demand power is greater than a, the extended range system works at W power point.

[0038] Preferably, the extended range system power calculation in the pure electric mode in the step S5 is specifically as follows:

[0039] When SOC is less than D, the engine is started forcibly, and the extended range system starts to work, if the vehicle demand power is less than b, the extended range system works at V power point, and when the vehicle demand power is greater than b, the extended range system works at W power point.

[0040] Wherein the residual SOC size relationship is:

[0041] A>B>C>D;

[0042] The vehicle demand power size relationship is:

[0043] a>b>c;

[0044] The extended range system power point size relationship is:

[0045] W>V>M>X>N>Z.

[0046] The present application has the following beneficial effects:

[0047] The extended range engine power calculation method designed by the present application is applied to the accurate calculation of the extended range system power of the CNG gas-electric hybrid extended range electric vehicle under different working conditions, improves the extended range system power measurement precision and engine working efficiency under the condition of ensuring that the driving power meets the requirements, and has important significance for improving the vehicle performance and energy consumption optimization in the control strategy aspect.

[0048] The extended range engine power calculation method designed by the present application calculates the power of the driving system, the power battery and the high-voltage auxiliary parts, combines the engine friction power, the system conversion efficiency and other factors, and further more efficiently and reasonably calculates the accurate engine power as a key factor for evaluating the vehicle performance. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 It is an interval relationship diagram of the battery SOC value. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be further clearly and completely explained in the following with reference to the drawings in the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0051] Embodiment one.

[0052] A power calculation method for a range extended engine, the specific technical solutions are as follows:

[0053] Based on the energy flow structure of different hybrid systems, the vehicle energy flow balance equation is sorted out, and the vehicle energy flow formula is:

[0054] The driving system power = the range extender output power + the power battery power - the high-voltage auxiliary power.

[0055] The range extender output power can be obtained from the above formula. The driving system power is calculated by detecting the throttle opening degree, and the greater the throttle opening degree, the greater the driving motor output torque; the power battery power is mainly determined by the parameters of battery temperature, voltage and current according to the battery charge and discharge map table, and the high-voltage auxiliary power is the sum of the powers of PTC, steering motor, DCDC, air compressor, cooling unit and air conditioning compressor.

[0056] The vehicle energy flow balance equation is used for formula representation as:

[0057] P 驱 =P 发 ·η1+P 电 -P 辅

[0058] P 发 =(P 驱 +P 辅 +P 电 ) / η1

[0059] P 驱 =U·I

[0060]

[0061] P 辅 =P AC +P DC +P ACM +P EPS +P PTC +P TMS

[0062] Based on: P = U·I = T·n9550, mechanical power and electric power conversion comparison.

[0063] Preferably, the formula of the whole vehicle energy flow balance equation is:

[0064] P 发 is the engine power;

[0065] P 驱 is the driving system power, calculated based on the current vehicle speed, the throttle opening and the driving intention;

[0066] P 电 is the power battery power, determined by looking up the table based on the current cell temperature and the power amount; 辅 is the whole vehicle high-voltage auxiliary component power, real-time measurement + rated parameter comparison;

[0067] P AC is the high-voltage electric air conditioner power, real-time measurement + rated parameter comparison;

[0068] P DC is the whole vehicle DCDC power, real-time measurement + rated parameter comparison;

[0069] P ACM is the high-voltage air pump power, real-time measurement + rated parameter comparison;

[0070] P EPS is the high-voltage steering assist motor power, real-time measurement + rated parameter comparison;

[0071] P PTC is the high-voltage electric heating power, real-time measurement + rated parameter comparison;

[0072] P TMS is the thermal management unit power, real-time measurement + rated parameter comparison;

[0073] Table 1: Power battery system charging map table.

[0074]

[0075] Table 1: Power battery system discharging map table.

[0076]

[0077] P 增程器 is the sum of all auxiliary component powers;

[0078] η 增程 is the extended range system working efficiency;

[0079] Whole vehicle required power = P e + P 辅 .

[0080] Auxiliary power consumption calculation: All auxiliary power consumption is detected by increasing current and voltage sensors in the high-voltage circuit, and the auxiliary power consumption is accurately calculated by real-time detection data.

[0081] Power battery power measurement: Based on the selected power battery charge-discharge map characteristics, the charge-discharge map parameters are preset in the vehicle control program, and the battery charge-discharge power is determined by real-time table lookup.

[0082] Drive system power measurement: Based on the vehicle driving demand power, the throttle-torque control data is calibrated (the drive system output torque is calibrated according to vehicle speed, throttle opening, etc.).

[0083] Based on the vehicle energy flow formula, while meeting the vehicle driving demand power and auxiliary power consumption, the range extending system power is adjusted based on the battery SOC (state of charge), and the engine works efficiently. The technical solution has been applied in CNG gas-electric hybrid traction vehicles.

[0084] The range extending system works in the following modes:

[0085] The range extending system vehicle is divided into hybrid mode and pure electric mode as follows:

[0086] In hybrid mode, after the vehicle starts, the vehicle controller starts to delay, the delay time ts, after the delay time ends, the engine starts, the engine enters idle operation, the vehicle controller monitors the power battery SOC and the current vehicle demand power in real time, and calculates the range extending system power as follows:

[0087] When SOC>A, if the vehicle demand power

[0088] When B<SOC<A, if the vehicle demand power

[0089] When C<SOC<B, if the vehicle demand power

[0090] When SOC < C, if the vehicle demand power < c, the extended range system works at X power point, when b > vehicle demand power > c, the extended range system works at M power point, when a > vehicle demand power > b, the extended range system works at V power point, when vehicle demand power > a, the extended range system works at W power point.

[0091] After the vehicle starts in the pure electric mode, the vehicle mainly drives through the battery, when the battery power is low, the extended range system is automatically started to generate electricity, which is as follows:

[0092] When SOC < D, the engine is forced to start, and the extended range system starts to work, if the vehicle demand power < b, the extended range system works at V power point, when the vehicle demand power > b, the extended range system works at W power point.

[0093] Where the remaining SOC size relationship is:

[0094] A > B > C > D;

[0095] The vehicle demand power size relationship is:

[0096] a > b > c;

[0097] The extended range system power point size relationship is:

[0098] W > V > M > X > N > Z.

[0099] The main parameter selection and determination standard are as follows:

[0100] 1. The SOC size is related to the battery selection capacity, which is determined based on the battery charging and discharging capacity.

[0101] 2. The demand power is dynamically adjusted according to the current driving conditions of the vehicle.

[0102] 3. The extended range system power point selection basis: ① The maximum output power of the extended range system; ② The efficiency of the extended range system at 6 power points is optimal; ③ The extended range system power point meets the vehicle energy balance formula; ④ The extended range system output power is dynamically adjusted according to the power point. The vehicle controller judges the power point conditions in turn, selects the best power point, and sends the torque command to the extended range system for execution.

[0103] 4. The specific vehicle model power range selection, demand power definition, and extended range system power point definition are different.

[0104] 5. The VCU determines whether to activate the range extender and the required power output based on the SOC value and the estimated power consumption of the entire vehicle. This ensures that the battery's SOC remains within a suitable range. When the SOC is too high, it tends to discharge the battery; when the SOC is too low, it tends to charge the battery, maintaining a dynamic balance in the battery's SOC. Figure 1 As shown.

[0105] This invention is not limited to the above-described embodiments. Anyone should know that any structural changes made under the guidance of this invention, and any technical solutions that are the same as or similar to this invention, fall within the protection scope of this invention.

[0106] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A method for calculating the power of a range extended engine, characterized in that, It comprises the following steps: S1, based on different hybrid system energy flow structure, arrange the whole vehicle energy flow balance equation: Drive system power = range extender output power + power battery power - high voltage auxiliary power, the calculation of the range extender output power; S2, drive system power is calculated by detecting the results of throttle opening, the greater the throttle opening, the greater the output torque of the drive motor; The power of power battery is mainly determined by the parameters of battery temperature, voltage and current according to the battery charge and discharge map table, and the power of high voltage auxiliary is the sum of PTC, steering motor, DCDC, air compressor, cooling unit and air conditioning compressor power; S3, the working mode of range extending system vehicle is divided into hybrid mode and pure electric mode; S4, after the vehicle starts in hybrid mode, the vehicle controller starts to delay, the delay time ts, after the delay time ts, the engine starts, the engine enters idle operation, the vehicle controller monitors the power battery SOC and the current vehicle demand power in real time, and calculates the range extending system power; S5, in pure electric mode, the vehicle is mainly driven by battery, when the battery power is low, the range extending system is started automatically to generate electricity.

2. The method of claim 1, wherein, The whole vehicle energy flow balance equation in step S1 is used to express the formula as follows: P 驱 = P 发 · η1+ P 电 - P 辅 P 发 = (P 驱 + P 辅 + P 电 ) / η1 P 驱 = U - I P 辅 = P AC + P DC + P ACM + P EPS + P PTC + P TMS Based on: P = U.I = T.n9550, mechanical power and electric power conversion comparison.

3. The method of claim 2, wherein, In the formula of the whole vehicle energy flow balance equation: P 发 P for engine power; P 驱 To drive the system power, based on the current vehicle speed, the development of driving intention calculation; P 电 The power of the power battery is determined by looking up a table based on the current battery temperature and the power value. P 辅 For the whole vehicle high pressure auxiliary power, real-time measurement + rated parameter comparison; P AC For high-voltage electric air conditioning power, real-time measurement + rated parameter comparison; P DC For the whole vehicle DCDC power, real-time measurement + rated parameter comparison; P ACM For high-pressure air pump power, real-time measurement + rated parameter comparison; P EPS For high-pressure steering assist motor power, real-time measurement + rated parameter comparison; P PTC For high-voltage electric heating power, real-time measurement + rated parameter comparison; P TMS For thermal management unit power, real-time measurement + rated parameter comparison; P 增程器 - sum of all accessory powers; η 增程 - range extending system work efficiency; Total vehicle demand power = P e + P 辅 .

4. The method of claim 1, wherein, The specific steps of calculating the range extending system power in step S4 in hybrid mode are as follows: ① When SOC > A, if the whole vehicle demand power < c, the engine enters idle mode, when b > whole vehicle demand power > c, the range extending system works at Z power point, when a > whole vehicle demand power > b, the range extending system works at X power point, when the whole vehicle demand power > a, the range extending system works at V power point; ② When B < SOC < A, if the whole vehicle demand power < c, the range extending system works at Z power point, when b > whole vehicle demand power > c, the range extending system works at N power point, when a > whole vehicle demand power > b, the range extending system works at M power point, when the whole vehicle demand power > a, the range extending system works at V power point; ③ When C < SOC < B, if the whole vehicle demand power < c, the range extending system works at N power point, when b > whole vehicle demand power > c, the range extending system works at X power point, when a > whole vehicle demand power > b, the range extending system works at M power point, when the whole vehicle demand power > a, the range extending system works at V power point; ④ When SOC < C, if the whole vehicle demand power < c, the range extending system works at X power point, when b > whole vehicle demand power > c, the range extending system works at M power point, when a > whole vehicle demand power > b, the range extending system works at V power point, when the whole vehicle demand power > a, the range extending system works at W power point.

5. The method of claim 4, wherein, The specific steps of calculating the range extending system power in step S5 in pure electric mode are as follows: When SOC < D, the engine is started compulsively, the extended range system starts to work, if the whole vehicle demand power < b, the extended range system works at V power point, when the whole vehicle demand power > b, the extended range system works at W power point; Wherein the residual SOC size relationship is: A > B > C > D; The whole vehicle demand power size relationship is: a > b > c; The extended range system power point size relationship is: W > V > M > X > N > Z.

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