Floor-type GPF Carbon Accumulation Test Weighing the Whole Vehicle Quick Heat Preservation Control Method and System

Abstract

The present invention relates to a quick heat preservation control method and system for weighing a whole vehicle in a floor-type GPF carbon accumulation test. The control method includes: after completing the GPF whole vehicle carbon accumulation test, keeping the engine running at idle speed, adjusting the idle speed and idle reserve torque of the engine to make the highest value of the internal temperature of the GPF reach the ideal heat preservation range, and maintaining the engine running for a predetermined time; then adjusting the idle target air-fuel ratio to a lean state to charge oxygen into the three-way catalytic converter and the GPF. After the oxygen is filled, the engine is turned off, the vehicle is lifted to quickly disassemble the GPF and transfer it to a high-precision weighing device, and the weight of the GPF is measured at each weighing and measuring temperature point. In the present invention, by maintaining the GPF temperature in the ideal heat preservation range and then quickly disassembling the GPF and timely transferring the GPF to a high-precision weighing device, the weighing of the GPF in the vehicle carbon accumulation test is not restricted by the muffle furnace equipment, and the test cost can be saved and the development cycle can be shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field of GPF carbon accumulation test, and relates to a floor-type GPF carbon accumulation test weighing vehicle quick insulation control method and system. Background Art

[0002] Gasoline particulate filters (GPFs) are widely used in hybrid vehicles and pure internal combustion engine vehicles in the National VI stage, and GPF carbon accumulation test weighing is an important part of GPF calibration development. Traditional vehicle GPF carbon accumulation test weighing usually requires driving carbon accumulation in a low-temperature environment, cooling the vehicle, disassembling the GPF, heating and heat preservation in a muffle furnace, and GPF weighing. However, the muffle furnace equipment is large in size and heavy in weight, which is not convenient for regional transportation and carrying in various special road tests. Therefore, it has caused serious equipment resource limitations for GPF carbon accumulation test weighing.

[0003] GPF can be divided into tightly coupled GPF and floor GPF according to the installation form. For tightly coupled GPF, since the removal of GPF is limited by the space in the engine compartment, it is impossible to install and remove it quickly. It is necessary to wait for the engine and exhaust system to be completely cooled before it can be safely removed. The weighing of GPF needs to be carried out at a high temperature of about 300°C. Therefore, for the carbon accumulation test of tightly coupled GPF, the heating and insulation link of the muffle furnace equipment is still indispensable. For the floor GPF, since it is located at the bottom of the car, it is possible to achieve quick disassembly by lifting the vehicle and installing quick-release flanges at both ends of the GPF. Therefore, for the floor GPF, by improving the test method, it is possible to save the heating and insulation link of the muffle furnace equipment to improve the convenience of test weighing. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a quick insulation control method and system for a floor-type GPF carbon accumulation test weighing vehicle that is not restricted by the use of muffle furnace equipment.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A floor-type GPF carbon accumulation test weighing vehicle quick insulation control method comprises the following steps:

[0007] S1. After the GPF vehicle carbon accumulation test is completed, keep the engine in an idling state; and observe the values of each temperature measuring point inside the GPF, and wait for the temperature to reach a stable state;

[0008] S2. Use the highest measured value among the temperature measurement points inside the GPF as the highest value of the GPF internal temperature; if the highest value of the GPF internal temperature is within the ideal heat preservation range, perform step S4; if the highest value of the GPF internal temperature is lower than the ideal heat preservation range, perform step S3;

[0009] S3. Increase the engine idle speed and / or increase the engine idle reserve torque until the highest value of the GPF internal temperature reaches the ideal heat preservation range, then perform step S4;

[0010] S4. Keep the engine in the current idle running state and maintain the engine operation for a predetermined time within the GPF ideal heat preservation range;

[0011] S5. Adjust the engine idle target air-fuel ratio to the preset final value of the idle target air-fuel ratio, make the idle target air-fuel ratio in a lean state, and oxygenate the three-way catalytic converter and the GPF;

[0012] S6. After the three-way catalytic converter and the GPF are filled with oxygen, turn off the engine, lift the vehicle and quickly remove the GPF;

[0013] S7. Transfer the GPF to a high-precision weighing device for natural cooling, and monitor the internal temperature of the GPF through the temperature measurement points inside the GPF;

[0014] S8. Measure the weight of the GPF at each predetermined carbon accumulation test weighing measurement temperature point and record the measurement data.

[0015] Further, a first temperature measurement point, a second temperature measurement point, and a third temperature measurement point are respectively arranged at the 1 / 6, 1 / 2, and 5 / 6 positions in the exhaust gas flow direction inside the GPF, and the first temperature measurement point, the second temperature measurement point, and the third temperature measurement point are all close to the axis of the GPF.

[0016] Further, quick-release flanges are respectively installed at both ends of the GPF. In step S1, after the GPF vehicle carbon accumulation test is completed, drive the vehicle slowly to the lift and park it, and keep the engine in the normal idle running state; in step S6, after the engine is turned off, immediately lift the vehicle by the lift; and quickly remove the GPF through the quick-release flanges at both ends of the GPF.

[0017] Further, the GPF ideal heat preservation range is 390°C to 410°C.

[0018] Further, step S3 includes the following sub-steps:

[0019] S301. Increase the engine idle speed;

[0020] S302. Determine whether the engine's idle speed has reached or exceeded the idle limit stable speed; if it has reached or exceeded the idle limit stable speed, execute step S304; otherwise, execute step S303.

[0021] S303. Determine whether the maximum value of the internal temperature of the GPF has reached the ideal heat preservation range; if it has reached the ideal heat preservation range, execute step S4; otherwise, return to execute step S301.

[0022] S304. Maintain the engine's idle speed at the idle limit stable speed.

[0023] S305. Increase the engine's idle reserve torque.

[0024] S306. Determine whether the maximum value of the internal temperature of the GPF has reached the ideal heat preservation range; if it has reached the ideal heat preservation range, execute step S4; otherwise, return to execute step S305.

[0025] Furthermore, in step S4, the time for maintaining the engine operation within the ideal heat preservation range of the GPF is greater than or equal to 500 s.

[0026] Furthermore, in step S5, the method for determining whether the three-way catalytic converter and the GPF are filled with oxygen is as follows: Calculate the minimum oxygen filling time t that makes the three-way catalytic converter and the GPF filled with oxygen according to the final value of the engine's idle target air-fuel ratio. min When the oxygen filling time of the three-way catalytic converter and the GPF is greater than or equal to the minimum oxygen filling time t min , it is determined that the three-way catalytic converter and the GPF are filled with oxygen.

[0027] Calculate the minimum oxygen filling time t min The formula for is:

[0028]

[0029] where the unit of the minimum oxygen filling time t min is s; M twc represents the maximum oxygen storage capacity of the three-way catalytic converter, and the unit is mg; M gpf is the maximum oxygen storage capacity of the GPF, and the unit is mg; t soft represents the execution cycle of the engine control algorithm software, and the unit is ms; M intk represents the engine intake air mass flow calculated by the engine control algorithm, and the unit is kg / h; L last represents the final value of the engine's idle target air-fuel ratio; T0 is the reserved time margin, and the unit is s.

[0030] Furthermore, in step S8, the predetermined carbon accumulation test weighing measurement temperature points include three temperature points: 330 °C, 300 °C, and 280 °C.

[0031] A floor - type GPF carbon accumulation test weighing vehicle quick heat - preservation control system, including

[0032] A rotational speed sensor, used to measure the rotational speed of the engine crankshaft;

[0033] An oxygen sensor, used to measure the exhaust gas air - fuel ratio signal at the front end of the three - way catalytic converter and the exhaust gas Nernst voltage signal at the rear end of the three - way catalytic converter;

[0034] A three - way catalytic converter, used for the treatment of engine exhaust gas pollutants;

[0035] A GPF, used for the treatment of engine exhaust particulate pollutants; quick - release flanges are respectively arranged at both ends of the GPF;

[0036] A temperature acquisition unit, used to set at least one test measuring point in the exhaust gas flow direction inside the GPF, and collect the temperature values of each temperature measuring point and send them to the communication unit;

[0037] A parameter calibration unit is used to monitor the temperature inside the GPF and the parameters of the engine, and modify the calibration quantities of the GPF heat - preservation rotational speed increase request F n 、the GPF heat - preservation reserve torque increase request calibration quantity F t and the GPF oxygen - charging request calibration quantity F 02 values;

[0038] A communication unit, used for communication between the engine controller and the parameter calibration unit, and sending the temperature values collected by the temperature acquisition unit to the parameter calibration unit;

[0039] An engine controller, used to adjust the idle rotational speed, idle reserve torque and idle target air - fuel ratio of the engine according to the calibration values calibrated by the parameter calibration unit, so that the highest value of the temperature inside the GPF is in the ideal heat - preservation interval.

[0040] Furthermore, the engine controller includes

[0041] A calibration data storage unit, used to store the calibration quantities of the idle target rotational speed final value, idle reserve torque final value and idle target air - fuel ratio of the engine calibrated by the parameter calibration unit for other modules of the dedicated engine controller for calibration development to call;

[0042] An idle rotational speed control module, used to determine the idle target rotational speed final value of the engine, so that the highest value of the temperature inside the GPF reaches the ideal heat - preservation interval;

[0043] A reserve torque control module, used to determine the idle reserve torque final value of the engine, so that the highest value of the temperature inside the GPF reaches the ideal heat - preservation interval;

[0044] An air-fuel ratio control module, which is used to determine the final value of the target air-fuel ratio at idle speed during engine operation;

[0045] An engine control algorithm module, which is used to provide a basic algorithm for the normal operation of the engine, calculate and output the intake air mass flow M of the engine intk , calculate the minimum oxygen filling time t for filling the three-way catalyst and GPF with oxygen min , and adjust the idle speed, idle reserve torque and target air-fuel ratio of the engine according to the calibration values calibrated by the parameter calibration unit.

[0046] In the present invention, by online adjusting the engine idle speed and reserve torque on the vehicle, and monitoring the GPF temperature through the temperature measuring point installed on the GPF, maintaining the floor-type GPF temperature within an ideal heat preservation range, and then by quickly disassembling the GPF, timely transferring the GPF to a high-precision weighing device, recording the GPF weight after the GPF naturally cools to the weighing temperature point, the complete GPF weighing process is completed, providing a reliable weighing result for GPF calibration, enabling the carbon accumulation test weighing of vehicles equipped with floor-type GPFs to be not restricted by muffle furnace equipment, significantly improving the convenience of GPF carbon accumulation test weighing in winter low-temperature road tests and various adaptability road tests, saving test costs and shortening the development cycle. Description of the Drawings

[0047] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0048] Figure 1 is a flowchart of a preferred embodiment of the vehicle fast heat preservation control method for floor-type GPF carbon accumulation test weighing of the present invention.

[0049] Figure 2 is a flowchart of step S3.

[0050] Figure 3 is a structural block diagram of a preferred embodiment of the vehicle fast heat preservation control system for floor-type GPF carbon accumulation test weighing of the present invention.

[0051] Figure 4 is a flowchart of GPF heat preservation target idle speed control.

[0052] Figure 5 is a flowchart of GPF heat preservation idle speed torque control.

[0053] Figure 6 is a flowchart of GPF heat preservation target air-fuel ratio control.

[0054] Figure 7Flow chart for completing the whole vehicle cumulative carbon weighing and heat preservation control process of GPF. Detailed implementation manners

[0055] The following uses specific specific examples to illustrate the implementation manners of the present invention. The diagrams provided in the following embodiments only schematically illustrate the basic concept of the present invention. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0056] As Figure 1 shown, the present invention discloses a floor - type GPF cumulative carbon test weighing whole vehicle fast heat preservation control method. A preferred embodiment of the floor - type GPF cumulative carbon test weighing whole vehicle fast heat preservation control method of the present invention includes the following steps:

[0057] S1. After the GPF whole vehicle cumulative carbon test is completed, drive the vehicle slowly to the lift and park it, and keep the engine running at normal idle speed. At the same time, observe the values of each temperature measurement point inside the gasoline particulate filter GPF, and wait for the temperature to reach a stable state. Preferably, a first temperature measurement point, a second temperature measurement point, and a third temperature measurement point are respectively set at the 1 / 6, 1 / 2, and 5 / 6 positions in the exhaust gas flow direction inside the GPF. The first temperature measurement point, the second temperature measurement point, and the third temperature measurement point are all close to the axis of the GPF. A temperature thermocouple is arranged at each temperature measurement point to measure the temperature value at that place.

[0058] S2. Take the highest measured value among the temperature measurement points inside the GPF as the highest value T of the internal temperature of the GPF max ; take 390°C - 410°C as the ideal heat preservation interval of the GPF. If the highest value T of the internal temperature of the GPF max is within the ideal heat preservation interval, it means that the internal temperature of the GPF meets the requirements, and step S4 is executed. If the highest value T of the internal temperature of the GPF max is lower than the ideal heat preservation interval, it means that the internal temperature of the GPF is too low, and the internal temperature of the GPF needs to be increased, and step S3 is executed.

[0059] S3. Increase the idle speed of the engine and / or increase the idle reserve torque of the engine so that the highest value T of the internal temperature of the GPF max reaches the ideal heat preservation interval and then execute step S4. As Figure 2 shown, this step may specifically include the following sub - steps:

[0060] S301. Increase the idle speed of the engine. The idle speed of the engine can be increased sequentially in a predetermined step (for example, 50 rpm).

[0061] S302. Determine whether the idle speed of the engine has reached or exceeded the idle limit stable speed N max ; the idle limit stable speed Nmax Generally around 2000 rpm. If it reaches or exceeds the idle limit stable speed N max It indicates that the idle speed of the engine cannot be increased any further, and step S304 is executed to no longer increase the idle speed of the engine; otherwise, step S303 is executed.

[0062] S303. Judge whether the maximum value T of the internal temperature of the GPF max reaches the ideal heat preservation range; if it reaches the ideal heat preservation range, step S4 is executed; otherwise, return to execute step S301 to continue increasing the idle speed of the engine.

[0063] S304. Maintain the idle speed of the engine at the idle limit stable speed N max .

[0064] S305. Increase the idle reserve torque of the engine, and the idle reserve torque of the engine can be increased successively by a predetermined step size (for example, 0.2 N).

[0065] S306. Judge whether the maximum value T of the internal temperature of the GPF max reaches the ideal heat preservation range; if it reaches the ideal heat preservation range, step S4 is executed and the idle reserve torque of the engine is no longer increased; otherwise, return to execute step S305 to continue increasing the idle reserve torque of the engine.

[0066] Of course, in step S3, the idle reserve torque of the engine can also be adjusted first. When increasing the idle reserve torque cannot make the maximum value T of the internal temperature of the GPF max reach the ideal heat preservation range, then increase the idle speed of the engine. Or adjust the idle speed of the engine and the idle reserve torque of the engine simultaneously to make the maximum value T of the internal temperature of the GPF max reach the ideal heat preservation range.

[0067] S4. Keep the engine running at the current idle state and maintain the engine running for a predetermined time t in the ideal heat preservation range of the GPF b , so that other areas outside the temperature measurement point are fully heated. Generally, the time t for maintaining the engine running in the ideal heat preservation range of the GPF b is not less than 500 s.

[0068] S5. Debug the idle target air-fuel ratio of the engine to the preset final value of the idle target air-fuel ratio, and the final value of the idle target air-fuel ratio can be 1.05 - 1.1, so that the idle target air-fuel ratio is in a lean state; for example, the final value of the idle target air-fuel ratio can be set to 1.05 to oxygenate the three-way catalytic converter TWC and GPF; after the TWC and GPF are filled with oxygen, turn off the engine. Considering that the GPF coating has a certain oxygen storage capacity, different oxygen contents before and after weighing will affect the weight of the GPF. Therefore, in this embodiment, before weighing, the TWC and GPF are oxygenated for a specific duration by adjusting the target air-fuel ratio to a lean state to maintain the consistency of the GPF weighing reference.

[0069] The method for judging whether the TWC and GPF are filled with oxygen is: calculate the minimum oxygenation time t required to fill the TWC and GPF according to the final value of the idle target air-fuel ratio of the engine min When the oxygenation time of the TWC and GPF is greater than or equal to the minimum oxygenation time t min it is determined that the TWC and GPF are filled with oxygen.

[0070] Calculate the minimum oxygenation time t min The formula is:

[0071]

[0072] where the minimum oxygenation time t min is in the unit of s; M twc represents the maximum oxygen storage capacity of the three-way catalytic converter, in the unit of mg; M gpf is the maximum oxygen storage capacity of the GPF, in the unit of mg; t soft represents the execution cycle of the engine control algorithm software, in the unit of ms; M intk represents the engine intake air mass flow calculated by the engine control algorithm, in the unit of kg / h; L last represents the final value of the idle target air-fuel ratio of the engine, dimensionless, generally 1.05 - 1.1; T0 is the time margin reserved considering possible small fluctuations in the actual air-fuel ratio and intake air mass flow, in the unit of s; for example, T0 = 10 s can be taken.

[0073] S6. After the engine is turned off, immediately lift the vehicle with a hoist; and quickly disassemble the GPF through the quick-release flanges at both ends of the GPF, and transfer the GPF to a high-precision weighing device for natural cooling before the internal temperature of the GPF drops to the highest carbon accumulation test weighing measurement temperature point (for example, 330 °C), and at the same time monitor the internal temperature of the GPF through each temperature measurement point inside the GPF.

[0074] S7. The weight of the GPF is measured at each predetermined carbon accumulation test weighing measurement temperature point. Generally, the weight of the GPF is measured at three temperature points of 330°C, 300°C, and 280°C. The measurement data is recorded, and thus a complete GPF carbon accumulation test weighing is completed, providing a reliable weighing result for GPF calibration.

[0075] Since the floor-mounted GPF is usually directly below the vehicle chassis, if the vehicle is lifted and combined with tooling facilities such as quick-release flanges, rapid installation and disassembly can be achieved in a short time. If the GPF is transferred to a high-precision weighing device before the GPF temperature cools to the weighing temperature, the muffle furnace heating and insulation link can be omitted, thus lifting the restriction of the muffle furnace equipment resources on the GPF vehicle carbon accumulation test. Therefore, in this embodiment, the engine idle speed and reserve torque are adjusted online on the vehicle, and the GPF temperature is monitored through the temperature measurement points installed on the GPF, maintaining the floor-mounted GPF temperature within an ideal heat preservation range. Then, by quickly disassembling the GPF and promptly transferring the GPF to a high-precision weighing device, the GPF weight is recorded after the GPF naturally cools to the weighing temperature point, completing a complete GPF weighing process, providing a reliable weighing result for GPF calibration, omitting the muffle furnace heating and insulation process, saving the test cost, shortening the development cycle, and improving the flexibility of the GPF road test.

[0076] As Figure 3 shown, the present invention also discloses a quick heat preservation control system for the whole vehicle of the floor-mounted GPF carbon accumulation test weighing. A preferred embodiment of the quick heat preservation control system for the whole vehicle of the floor-mounted GPF carbon accumulation test weighing of the present invention includes a rotational speed sensor and an oxygen sensor installed on the engine, a three-way catalytic converter TWC, a gasoline particulate filter GPF, a temperature acquisition unit, a parameter calibration unit, a communication unit, and an engine controller. Among them, the rotational speed sensor is used to measure the engine crankshaft rotational speed. The oxygen sensor includes a front oxygen sensor installed at the front end of the TWC and a rear oxygen sensor installed at the rear end of the TWC. The front oxygen sensor can adopt a linear oxygen sensor and is used to measure the exhaust gas air-fuel ratio signal before the TWC; the rear oxygen sensor can adopt a switching oxygen sensor and is used to measure the exhaust gas Nernst voltage signal after the TWC. The three-way catalytic converter TWC is used for the treatment of engine exhaust gas pollutants. The gasoline particulate filter GPF is used for the treatment of engine exhaust gas particulate pollutants; quick-release flanges are respectively arranged at both ends of the GPF; to facilitate the quick disassembly of the GPF.

[0077] The temperature acquisition unit is used to set at least one test measuring point in the exhaust gas flow direction inside the GPF, and collect the temperature values of each temperature measuring point and send them to the communication unit. The temperature acquisition unit preferably includes a temperature acquisition circuit and three thermocouples. The three thermocouples are respectively arranged at the 1 / 6, 1 / 2, and 5 / 6 positions in the exhaust gas flow direction inside the GPF, and as close as possible to the axis of the GPF, so as to form a first temperature measuring point at the 1 / 6 position inside the GPF, a second temperature measuring point at the 1 / 2 position inside the GPF, and a third temperature measuring point at the 5 / 6 position inside the GPF.

[0078] The parameter calibration unit may include a calibration computer and calibration software, and is used to monitor the temperature inside the GPF and the parameters of the engine, as well as modify the calibration quantity F of the GPF heat preservation speed increase request n , the calibration quantity F of the GPF heat preservation reserve torque increase request t and the calibration quantity F of the GPF oxygen charging request. 02 value.

[0079] The specific method for modifying the calibration quantity F of the GPF heat preservation speed increase request n , the calibration quantity F of the GPF heat preservation reserve torque increase request t is as follows: When the engine is in a normal idle running state, if the highest value T of the temperature inside the GPF max is within the ideal heat preservation interval, the parameter calibration unit makes the calibration quantity F of the GPF heat preservation speed increase request n = 0, and makes the calibration quantity F of the GPF heat preservation reserve torque increase request t = 0. If the engine is in a normal idle running state and the highest value T of the temperature inside the GPF max is lower than the ideal heat preservation interval, the parameter calibration unit makes the calibration quantity F of the GPF heat preservation speed increase request n > 0 (for example, F n can be made = 1) to increase the idle speed of the engine. If the idle speed of the engine reaches the idle limit stable speed, the parameter calibration unit makes the calibration quantity F of the GPF heat preservation reserve torque increase request t > 0 (for example, F t can be made = 1) to increase the idle reserve torque of the engine and make the highest value T of the temperature inside the GPF max be within the ideal heat preservation interval.

[0080] The specific method for modifying the calibration quantity F of the GPF oxygen charging request 02 is as follows: When the highest value T of the temperature inside the GPF max is lower than the ideal heat preservation interval, or the highest value T of the temperature inside the GPF maxAfter reaching the ideal heat preservation range, when the time for maintaining the engine operation in the GPF ideal heat preservation range is less than 500S, the parameter calibration unit makes the GPF oxygen charging request calibration quantity F 02 = 0; when the time for maintaining the engine operation in the GPF ideal heat preservation range reaches or exceeds 500s, the parameter calibration unit makes the GPF oxygen charging request calibration quantity F 02 > 0 (for example, F 02 can be made to be 1).

[0081] The communication unit is used for the communication between the engine controller and the parameter calibration unit, and for sending the temperature value collected by the temperature acquisition unit to the parameter calibration unit. For example, the communication unit transmits various parameter signals of the engine controller and the temperature signals of the temperature acquisition unit to the parameter calibration unit, and at the same time sends the calibrated quantity modified in the parameter calibration unit to the engine controller to change the operation parameters in the engine controller.

[0082] The engine controller is a special calibration development engine controller obtained by adding the function of adjusting the idle speed, idle reserve torque and idle target air-fuel ratio of the engine according to the calibration value on the basis of the existing engine controller; it is used to adjust the idle speed, idle reserve torque and idle target air-fuel ratio of the engine according to the calibration value calibrated by the parameter calibration unit, so that the highest value T max of the internal temperature of the GPF is in the ideal heat preservation range, and after the time for maintaining the engine operation in the GPF ideal heat preservation range reaches or exceeds 500s, the three-way catalytic converter and the GPF are filled with oxygen.

[0083] The engine controller may include a calibration data storage unit, an idle speed control module, a reserve torque control module, an air-fuel ratio control module and an engine control algorithm module. The calibration data storage unit is used to store the GPF heat preservation speed increase request calibration quantity F n , the GPF heat preservation reserve torque increase request calibration quantity F t and the GPF oxygen charging request calibration quantity F 02 calibrated by the parameter calibration unit for other modules of the special calibration development engine controller to call.

[0084] The idle speed control module adds the GPF heat preservation speed increase request calibration quantity F nor and the GPF heat preservation target speed offset table on the basis of the idle speed control module of the existing engine controller (a normal idle target speed control table is set in the idle speed control module of the existing engine controller, and the normal idle target speed N n of the engine is stored in the normal idle target speed control table) to determine the final value of the idle target speed of the engine, so that the highest value T maxReach the ideal heat preservation range. Among them, the calibrated value F of the GPF heat preservation speed increase request n is used to judge the final value N of the idle target speed of the engine last Whether it is necessary to increase the GPF heat preservation offset speed N nor on the basis of the normal idle target speed N of the engine off The GPF heat preservation target speed offset table is used to store the GPF heat preservation offset speed N off . Such as Figure 4 shown, when F n =0, it indicates that the highest value T of the internal temperature of the GPF max is in the ideal heat preservation range and there is no need to increase the idle speed of the engine; at this time, the final value N of the idle target speed of the engine last is equal to the normal idle target speed N nor . When F n >0, it indicates that the highest value T of the internal temperature of the GPF max is lower than the ideal heat preservation range and the idle speed of the engine needs to be increased; at this time, the final value N of the idle target speed of the engine last is equal to the sum of the normal idle target speed N nor and the GPF heat preservation offset speed N off ; if the highest value T of the internal temperature of the GPF is still lower than the ideal heat preservation range at this time, the value of the GPF heat preservation offset speed N max can be increased in sequence according to a predetermined speed step value (for example, the speed step value can be 50 rpm) until the highest value T of the internal temperature of the GPF off is in the ideal heat preservation range or N max reaches the idle limit stable speed. The calculation formula of the final value N of the idle target speed is as follows: last last nor

[0085]

[0086] The reserve torque control module adds the calibrated value F of the GPF heat preservation reserve torque increase request t and the GPF heat preservation reserve torque offset table on the basis of the reserve torque control module of the existing engine controller (there is a normal idle reserve torque control table in the reserve torque control module of the existing engine controller, and the normal idle reserve torque control table stores the normal idle reserve torque T of the engine nor value) to determine the final value T of the idle reserve torque of the engine last max so that the highest value T of the internal temperature of the GPF t reaches the ideal heat preservation range. The calibrated value F of the GPF heat preservation reserve torque increase request t is used to judge the final value T of the idle reserve torque of the enginelast Whether it is necessary to increase the GPF heat preservation offset reserve torque T nor on the basis of the normal idle reserve torque T of the engine off , and the GPF heat preservation reserve torque offset table is used to store the GPF heat preservation offset reserve torque T off . As Figure 5 shown, when F t = 0, it indicates that the highest value T of the internal temperature of the GPF max is in the ideal heat preservation interval and there is no need to increase the idle reserve torque of the engine; at this time, the final value N of the idle target speed of the engine last is equal to the normal idle reserve torque T nor . When F t > 0, it indicates that the highest value T of the internal temperature of the GPF max is lower than the ideal heat preservation interval and it is necessary to increase the idle reserve torque of the engine; at this time, the final value T of the idle reserve torque of the engine last is equal to the sum of the normal idle reserve torque T nor and the GPF heat preservation offset reserve torque T off ; if the highest value T of the internal temperature of the GPF is still lower than the ideal heat preservation interval at this time, the value of the GPF heat preservation offset reserve torque T max can be increased sequentially according to a predetermined torque step value (for example, the torque step value can be taken as 0.2 N) until the highest value T of the internal temperature of the GPF off is in the ideal heat preservation interval. The calculation formula for the final value T of the idle reserve torque max is as follows: last The air-fuel ratio control module adds the GPF oxygen charging request calibration quantity F

[0087]

[0088] on the basis of the air-fuel ratio control module of the existing engine controller (the air-fuel ratio control module of the existing engine controller is provided with a normal idle target air-fuel ratio control table, and the normal idle target air-fuel ratio control table stores the value of the normal idle target air-fuel ratio L tar of the engine) and the GPF oxygen charging target air-fuel ratio control table, and is used to determine the final value L of the idle target air-fuel ratio when the engine is working 02 . The GPF oxygen charging request calibration quantity F last is used to judge whether it is necessary to charge oxygen to the TWC and the GPF; the GPF oxygen charging target air-fuel ratio control table is used to store the value of the GPF oxygen charging target air-fuel ratio L 02 , and the value of the GPF oxygen charging target air-fuel ratio L 02 is generally 1.05 - 1.1, preferably 1.05. As 02 shown, when F Figure 6 ​02 When it is 0, it indicates that there is no need to oxygenate the TWC and GPF; at this time, the final value L of the target air-fuel ratio at engine idle speed last is equal to the normal target air-fuel ratio L at engine idle speed tar . When F 02 > 0, it indicates that it is necessary to make the target air-fuel ratio at engine idle speed lean in order to oxygenate the TWC and GPF; at this time, the final value L of the target air-fuel ratio at engine idle speed last is equal to the target air-fuel ratio L for GPF oxygenation 02 . The final value L of the target air-fuel ratio at engine idle speed last is calculated as follows:

[0089]

[0090] The engine control algorithm module is used to provide the basic algorithm for the normal operation of the engine, calculate and output the engine intake air mass flow M intk , calculate the minimum oxygenation time t for filling the TWC and GPF with oxygen according to the final value of the target air-fuel ratio at engine idle speed min , and adjust the final value N of the target engine idle speed n , the final value T of the idle reserve torque t and the final value L of the target air-fuel ratio at engine idle speed 02 according to the calibration values (including F off , F off and F 02 ) calibrated by the parameter calibration unit and the values of N last , T last and L last , so as to adjust the engine idle speed, idle reserve torque and target air-fuel ratio at engine idle speed to ensure the correct execution of the final value N of the target engine idle speed last , the final value T of the idle reserve torque last and the final value L of the target air-fuel ratio at engine idle speed last . Among them, the formula for calculating the minimum oxygenation time t min is:

[0091]

[0092] where the unit of the minimum oxygenation time t min is s; M twc represents the maximum oxygen storage capacity of the three-way catalytic converter, with the unit of mg; M gpf is the maximum oxygen storage capacity of the GPF, with the unit of mg; t soft represents the execution cycle of the engine control algorithm software, with the unit of ms; M intkIndicates the engine intake air mass flow calculated by the engine control algorithm, with the unit of kg / h; T0 is the time margin reserved considering the actual air-fuel ratio and possible small fluctuations in the intake air mass flow, with the unit of s.

[0093] The working principle of this embodiment is as follows:

[0094] As Figures 3 to 7 shown, install the floor-type GPF carbon accumulation test weighing vehicle quick heat preservation control system of this embodiment on the vehicle and the engine. After the GPF vehicle carbon accumulation test is completed, drive the vehicle slowly to the lift and park it, and keep the engine in a normal idle running state. The parameter calibration unit obtains the values of the three temperature measurement points inside the GPF through the temperature acquisition unit and waits for the temperature to reach a stable state. After the temperature reaches a stable state, the parameter calibration unit uses the highest measured value among the three temperature measurement points as the highest value T of the temperature inside the GPF max , and determines whether the highest value T of the temperature inside the GPF max is within the ideal heat preservation interval of the GPF (i.e., 390°C < T max < 410°C). If the highest value T of the temperature inside the GPF max is lower than the ideal heat preservation interval (i.e., T max < 390°C), then the parameter calibration unit modifies the calibrated value of the GPF heat preservation speed increase request stored in the idle speed control module to make F n = 1. At this time, the final value N of the idle target speed of the engine last = N nor + N off ; when the engine control algorithm module adjusts the idle speed of the engine to reach the new N last and if the highest value T of the temperature inside the GPF max is still lower than the ideal heat preservation interval, the parameter calibration unit increases the value of N off by 50 rpm and makes the engine control unit recalculate the value of N last to increase the idle speed of the engine by 50 rpm. If the highest value T of the temperature inside the GPF max is still lower than the ideal heat preservation interval, the parameter calibration unit repeats the above adjustment process to increase the value of N off by 50 rpm each time until the highest value T of the temperature inside the GPF max is within the ideal heat preservation interval.

[0095] If the value of N last reaches or exceeds the idle limit stable speed N max and the highest value T of the temperature inside the GPF max is still lower than the ideal heat preservation interval; then stop increasing the value of N off , and maintain N last = Nmax ; The parameter calibration unit modifies the calibrated value of the GPF thermal insulation reserve torque boost request, making F t = 1. At this time, the final value of the engine's idle reserve torque T last = T nor + T off ; When the engine control algorithm module debugs the engine's idle reserve torque to reach a new T last and if the maximum value T max of the internal temperature of the GPF is still lower than the ideal thermal insulation range, the parameter calibration unit increases the value of T off by 0.2 N and causes the engine control unit to recalculate the value of T last , thereby increasing the engine's idle reserve torque by 0.2 N; if the maximum value T max of the internal temperature of the GPF is still lower than the ideal thermal insulation range, the parameter calibration unit repeats the above adjustment process, increasing the value of T off by 0.2 N each time until the maximum value T max of the internal temperature of the GPF is within the ideal thermal insulation range.

[0096] After the maximum value T max of the internal temperature of the GPF reaches the ideal thermal insulation range, keep the engine running at the current idle speed, maintain the engine operation in the GPF ideal thermal insulation range for no less than 500 s, so that other areas outside the internal temperature measurement point of the GPF are fully heated. After that, the parameter calibration unit modifies the calibrated value of the GPF oxygen filling request, making F 02 = 1. Assuming L 02 = 1.05, then the final value of the engine's idle target air-fuel ratio L last = L 02 = 1.05, and the engine control algorithm module debugs the engine's idle target air-fuel ratio to 1.05, making the idle target air-fuel ratio in a lean state; oxygen is filled into the three-way catalytic converter TWC and the GPF. When the oxygen filling time reaches or exceeds the minimum oxygen filling time t min required to fill with oxygen, turn off the engine; and immediately lift the vehicle with a lift, quickly disassemble the GPF through the quick-release flanges at both ends of the GPF, transfer the GPF to a high-precision weighing device for natural cooling, and at the same time monitor the internal temperature of the GPF through three temperature measurement points. Weigh the GPF at three temperature points of 330 °C, 300 °C and 280 °C respectively and record the measurement data, that is, complete a complete GPF carbon accumulation test weighing.

[0097] In this embodiment, the engine idle speed and reserve torque can be adjusted online on the vehicle, the floor-type GPF temperature can be maintained within an ideal heat preservation range, the GPF can be quickly disassembled, and the GPF can be promptly transferred to a high-precision weighing device to record the GPF weight at the weighing temperature point. The muffle furnace heating and heat preservation process can be omitted in the GPF carbon accumulation test weighing process, thereby saving test costs, shortening the development cycle, and improving the flexibility of the GPF road test.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A quick heat preservation control method for weighing a whole vehicle in a floor-type GPF carbon accumulation test, characterized in that, It includes the following steps: S1. After the GPF vehicle cumulative carbon test is completed, keep the engine running at idle speed; and observe the values of each temperature measurement point inside the GPF, and wait for the temperature to reach a stable state; S2. Take the highest measured value among the temperature measurement points inside the GPF as the highest value of the GPF internal temperature; if the highest value of the GPF internal temperature is within the ideal heat preservation range, execute step S4; if the highest value of the GPF internal temperature is lower than the ideal heat preservation range, execute step S3; S3. Increase the idle speed of the engine and / or increase the idle reserve torque of the engine, and execute step S4 after the highest value of the GPF internal temperature reaches the ideal heat preservation range; S4. Keep the engine running at the current idle speed and maintain the engine running for a predetermined time within the GPF ideal heat preservation range; S5. Adjust the idle target air-fuel ratio of the engine to the preset final value of the idle target air-fuel ratio, make the idle target air-fuel ratio in a lean state, and oxygenate the three-way catalytic converter and the GPF; S6. After the three-way catalytic converter and the GPF are filled with oxygen, turn off the engine, lift the vehicle and quickly disassemble the GPF; S7. Transfer the GPF to high-precision weighing equipment for natural cooling, and at the same time monitor the internal temperature of the GPF through each temperature measurement point inside the GPF; S8. Measure the weight of the GPF at each predetermined cumulative carbon test weighing measurement temperature point and record the measurement data.

2. The quick heat preservation control method for weighing the whole vehicle in the floor-type GPF carbon accumulation test according to claim 1, wherein: A first temperature measurement point, a second temperature measurement point and a third temperature measurement point are respectively set at the 1 / 6, 1 / 2 and 5 / 6 positions in the exhaust gas flow direction inside the GPF, and the first temperature measurement point, the second temperature measurement point and the third temperature measurement point are all close to the axis of the GPF.

3. The quick heat preservation control method for the whole vehicle with floor type GPF carbon accumulation test weighing according to claim 1, characterized in that: Quick-release flanges are respectively installed at both ends of the GPF. In step S1, after the GPF vehicle cumulative carbon test is completed, drive the vehicle slowly to the lift and park it, and keep the engine running at normal idle speed; in step S6, after the engine is turned off, immediately lift the vehicle through the lift; and quickly disassemble the GPF through the quick-release flanges at both ends of the GPF.

4. The floor-type GPF carbon accumulation test weighing and vehicle quick heat preservation control method according to claim 1, wherein: The GPF ideal heat preservation range is 390°C to 410°C.

5. The floor-type GPF carbon accumulation test weighing vehicle quick heat preservation control method according to claim 1, characterized in that: Step S3 includes the following sub-steps: S301. Increase the idle speed of the engine; S302. Judge whether the idle speed of the engine reaches or exceeds the idle limit stable speed; if it reaches or exceeds the idle limit stable speed, execute step S304; otherwise, execute step S303; S303. Judge whether the highest value of the GPF internal temperature reaches the ideal heat preservation range; If it reaches the ideal heat preservation range, execute step S4; Otherwise, return to execute step S301; S304. Maintain the idle speed of the engine at the idle limit stable speed; S305. Increase the idle reserve torque of the engine; S306. Judge whether the highest value of the GPF internal temperature reaches the ideal heat preservation range; If it reaches the ideal heat preservation range, execute step S4; Otherwise, return to execute step S305.

6. The floor-type GPF carbon accumulation test weighing vehicle fast heat preservation control method according to claim 1, characterized in that: In step S4, the time for maintaining the engine running within the GPF ideal heat preservation range is greater than or equal to 500 s.

7. The quick heat preservation control method for weighing the whole vehicle during the floor type GPF carbon accumulation test as claimed in claim 1, wherein: In the step S5, the method for determining whether the three-way catalytic converter and the GPF are filled with oxygen is as follows: Calculate the minimum oxygen filling time for filling the three-way catalytic converter and the GPF with oxygen according to the final value of the idle target air-fuel ratio of the engine t min , when the oxygen filling time of the three-way catalytic converter and the GPF is greater than or equal to the minimum oxygen filling time t min , it is determined that the three-way catalytic converter and the GPF are filled with oxygen; Calculating the minimum oxygenation time t min The formula is: Among them, the minimum oxygen charging time t min has the unit of s; M twc represents the maximum oxygen storage capacity of the three-way catalytic converter, with the unit of mg; M gpf is the maximum oxygen storage capacity of the GPF, with the unit of mg; t soft represents the execution cycle of the engine control algorithm software, with the unit of ms; M intk represents the engine intake air mass flow calculated by the engine control algorithm, with the unit of kg / h; L last represents the final value of the idle target air-fuel ratio of the engine; T 0 is the reserved time margin, with the unit of s.

8. The quick heat preservation control method for the whole vehicle with floor type GPF carbon accumulation test weighing according to claim 1, characterized in that: In the step S8, the predetermined carbon accumulation test weighing measurement temperature points include three temperature points of 330 °C, 300 °C, and 280 °C.

9. A floor-type GPF carbon accumulation test weighing and vehicle quick heat preservation control system, characterized in that: Adopt the floor-type GPF carbon accumulation test weighing vehicle rapid heat preservation control method according to any one of claims 1 to 8, including a rotational speed sensor for measuring the rotational speed of the engine crankshaft; an oxygen sensor for measuring the exhaust gas air-fuel ratio signal at the front end of the three-way catalytic converter and the exhaust gas Nernst voltage signal at the rear end of the three-way catalytic converter; a three-way catalytic converter for treating engine exhaust gas pollutants; a GPF for treating engine exhaust particulate pollutants; quick-release flanges are respectively arranged at both ends of the GPF; a temperature acquisition unit for arranging at least one test measuring point in the exhaust gas flow direction inside the GPF and collecting the temperature values of each temperature measuring point and sending them to the communication unit; The parameter calibration unit is used to monitor the internal temperature of the GPF and the parameters of the engine, and modify the calibrated value of the GPF heat preservation speed increase request, F n , the calibrated value of the GPF heat preservation reserve torque increase request, F t and the calibrated value of the GPF oxygen charging request; F 02 value; a communication unit for communicating between the engine controller and the parameter calibration unit and sending the temperature values collected by the temperature acquisition unit to the parameter calibration unit; an engine controller for adjusting the idle speed, idle reserve torque, and idle target air-fuel ratio of the engine according to the calibration values calibrated by the parameter calibration unit, so that the highest value of the temperature inside the GPF is within the ideal heat preservation range.

10. The floor-type GPF carbon accumulation test weighing vehicle quick heat preservation control system according to claim 9, characterized in that: The engine controller includes a calibration data storage unit for storing the final values of the idle target speed, idle reserve torque final value, and the calibrated value of the idle target air-fuel ratio of the engine calibrated by the parameter calibration unit for other modules of the special engine controller for calibration development to call; an idle speed control module for determining the final value of the idle target speed of the engine so that the highest value of the temperature inside the GPF reaches the ideal heat preservation range; a reserve torque control module for determining the final value of the idle reserve torque of the engine so that the highest value of the temperature inside the GPF reaches the ideal heat preservation range; an air-fuel ratio control module for determining the final value of the idle target air-fuel ratio during engine operation; The engine control algorithm module is used to provide the basic algorithm for the normal operation of the engine, calculate and output the engine intake air mass flow rate M intk , calculate the minimum oxygen filling time to fill the three-way catalytic converter and GPF with oxygen t min , and adjust the engine idle speed, idle reserve torque, and idle target air-fuel ratio according to the calibration values calibrated by the parameter calibration unit.

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