A method for troubleshooting fuel consumption inconsistencies in mass-produced vehicles

Abstract

This invention is a method for troubleshooting fuel consumption consistency issues in mass-produced vehicles. It includes: 1. Inspecting fuel consumption acceptance vehicles during the development phase; 2. Inspecting and setting parameters for fuel consumption acceptance equipment during the development phase; 3. Recording fuel consumption acceptance test data during the development phase; 4. Inspecting fuel consumption consistency test vehicles, testing equipment, setting equipment parameters, and recording data; 5. Troubleshooting fuel consumption consistency issues. This invention improves the efficiency of fuel consumption consistency issue troubleshooting, shortens the troubleshooting time, and reduces the workload. Furthermore, it requires only one fuel consumption consistency verification test to determine the cause of the fuel consumption problem, further shortening the troubleshooting time. It can also quickly identify the area where the fuel consumption consistency problem occurs, eliminating the need to interchange subsystems or parts and repeatedly conduct fuel consumption tests, thus reducing the workload of fuel consumption issue troubleshooting.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology, specifically a method for troubleshooting fuel consumption consistency issues in mass-produced vehicles. Background Technology

[0002] National testing agencies conduct annual random checks on fuel consumption consistency for selected models from various automakers. Failure to meet these checks can lead to losses for automakers, such as production halts, changes to model announcements, suspension of new model applications, or fines. Fuel consumption consistency issues cause fluctuations in user fuel consumption, impacting vehicle reputation. Therefore, automakers are increasingly focused on controlling fuel consumption consistency in mass-produced vehicles, regularly conducting fuel consumption tests to determine if consistency meets standards. When high fuel consumption is detected in a mass-produced vehicle, identifying the underlying cause is a common challenge faced by all automakers.

[0003] There is limited literature on the consistency of vehicle fuel consumption. Some studies employ an elimination method, testing fuel consumption by swapping subsystems to rule out factors such as the engine, transmission, and exhaust system. Others focus on the electrical system as the source of fuel consumption differences through motor disconnection tests. Generator efficiency is tested to eliminate the generator's influence. Ultimately, the difference in energy consumption is determined to originate from electrical consumption and the initial battery charge. However, this method does not perform a vehicle condition check before testing, thus failing to rule out differences in initial battery SOC values. Furthermore, this method is complex, requiring repeated replacement of powertrain-related systems, resulting in numerous fuel consumption tests, increasing testing costs and operational errors. Some literature uses experimental data to illustrate how differences in vehicle break-in mileage, wheel stability, engine assembly, transmission assembly, and intake and exhaust assemblies affect the consistency of vehicle fuel consumption. It focuses on the impact of tire assembly consistency on fuel consumption, standardizing tire rolling resistance evaluation criteria and strengthening tire suppliers' control over rolling resistance production consistency. However, this paper only discusses the factors influencing fuel consumption consistency and does not explain how to determine the specific causes of vehicle fuel consumption consistency problems or the relevant subsystems or components causing the fuel consumption issues. Zhou Junxiao et al. analyzed the control of new vehicle fuel consumption consistency by examining the drive axle transmission and braking internal resistance of rear-wheel drive models, focusing on aspects such as component manufacturing precision consistency, vehicle assembly, stricter testing line control, and pre-test vehicle inspection. Other literature has identified key control items for the drive axle, aiming to improve overall vehicle fuel consumption consistency by controlling drive axle consistency. Both papers improve overall vehicle fuel consumption consistency by enhancing component consistency. However, they do not discuss troubleshooting methods for problems arising in overall vehicle fuel consumption consistency, or how to attribute fuel consumption issues to subsystems or components. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a method for troubleshooting fuel consumption consistency problems in mass-produced vehicles. This method can quickly identify the reasons for high fuel consumption in mass-produced vehicles and develop solutions based on the high fuel consumption, ensuring that the fuel economy of mass-produced vehicles meets the national fuel consumption consistency sampling inspection requirements.

[0005] The technical solution of this invention is described below in conjunction with the accompanying drawings:

[0006] A method for troubleshooting fuel consumption consistency issues in mass-produced vehicles includes the following steps:

[0007] Step 1: Inspect the fuel consumption test vehicles during the development phase;

[0008] Step 2: Inspect the fuel consumption acceptance equipment during the development phase and set its parameters;

[0009] Step 3: Record fuel consumption acceptance test data during the development phase;

[0010] Step 4: Inspect the fuel consumption consistency test vehicle, inspect the test equipment, set the equipment parameters, and record the data;

[0011] Step 5: Investigate the issue of inconsistent fuel consumption.

[0012] Furthermore, the specific method for step one is as follows:

[0013] The engine and transmission must be in the form of a C-sample or mass-produced part;

[0014] The engine and transmission control unit version numbers and calibration data numbers are in mass production status;

[0015] The tire pressure and model meet the requirements of the drawings;

[0016] The vehicle's four-wheel alignment parameters meet the drawing requirements; the battery's initial SOC is ≥90%, and the battery voltage is ≥12.3V;

[0017] The idle start-stop function is working normally.

[0018] The intake and exhaust systems are leak-proof;

[0019] The vehicle can enter a sleep mode after being locked.

[0020] The vehicle's fuel meets the requirements of the drawings;

[0021] The vehicle has no other fault codes affecting fuel consumption performance;

[0022] The break-in mileage for the vehicle should not exceed 300km.

[0023] Furthermore, if the inspection results do not meet the requirements, explanatory materials must be provided.

[0024] Furthermore, the specific method for step two is as follows:

[0025] The technical specifications of the rotary drum testing equipment meet the requirements of the sixth stage of emission limits and measurement methods for pollutants from light-duty vehicles.

[0026] Vehicle immersion time ≥ 6 hours;

[0027] The laboratory temperature was 23±5℃;

[0028] The vehicle's coasting curve used in the test shall be based on the values ​​in the test report.

[0029] Before the fuel consumption test, the vehicle should undergo a coasting test on the rotating drum to determine the drum loading curve.

[0030] Furthermore, the specific method for step three is as follows:

[0031] Before the fuel consumption test, the CAN bus device is started, and PT-CAN bus data is recorded during the test. The test data includes: fuel cut-off status, engine start / stop status, engine speed, air conditioning AC switch status, brake pedal status, torque without TCU request, throttle opening, accelerator opening, air conditioning compressor request, target gear, actual gear, cooling fan duty cycle, ambient temperature, wheel speed of all four wheels, vehicle speed, driver's seat belt status, lost torque, combustion torque, TCU requested torque, TCU speed request, DCT pressure plate speed, DCT output shaft speed, instantaneous fuel consumption, engine coolant temperature, battery SOC, battery SOC status, generator load, transmission operating mode, and total mileage.

[0032] Furthermore, the specific method for step four is as follows:

[0033] Conduct vehicle inspections for consistency testing, check and set parameters for the rotating equipment, refer to the fuel consumption acceptance test, and record PT-CAN bus data.

[0034] Furthermore, the specific method for step four is as follows:

[0035] Based on the vehicle speed signal, the time start point of the CAN bus data for the acceptance test and conformance test is aligned as follows:

[0036] 1) Analyze the issue of fuel consumption consistency;

[0037] Based on the trend of vehicle fuel consumption changes, the time period during which fuel consumption increases in the consistency fuel consumption test is determined. During the time period during which fuel consumption increases in the consistency fuel consumption test, the differences in transmission gear position, deceleration section oil level, engine speed, vehicle speed, engine coolant temperature, battery SOC change, engine torque loss, engine crankshaft output torque, and generator load are analyzed. Through the above analysis, the direction for troubleshooting fuel consumption consistency issues is clarified, and each system or component conducts further analysis and troubleshooting for the problems found.

[0038] 2) Analyze instantaneous fuel consumption data;

[0039] Instantaneous fuel consumption is defined as the total amount of fuel injected by the engine within 0.1 seconds; cumulative fuel consumption is defined as the total amount of fuel injected by the engine from the start of the test to a certain moment, i.e., the total instantaneous fuel consumption within that time period; the curve relating cumulative fuel consumption to time is defined as the cumulative fuel consumption curve; subtracting the cumulative fuel consumption curves of the consistency test and the acceptance test yields the fuel consumption trend curve of the vehicle in the consistency test relative to the acceptance test; the rising segment of the curve indicates that the fuel consumption in the consistency test is greater than that in the acceptance test within that time period, and the falling segment indicates that the fuel consumption in the consistency test is less than that in the acceptance test within that time period; by investigating other signals within that time period, the cause of the fuel consumption change is determined;

[0040] 3) Analyze the vehicle speed data;

[0041] From the start to a certain moment, the vehicle speed is integrated over time to obtain the vehicle's mileage at that moment; the relationship curve between mileage and time is defined as the mileage curve; the mileage curves of the consistency test and the acceptance test are subtracted to obtain the mileage change trend curves of the two tests; the rising segment of the curve indicates that the mileage of the consistency test is greater than that of the acceptance test within that time period, and the falling segment indicates that the mileage of the consistency test is less than that of the acceptance test within that time period; when the mileage change value of the acceleration segment continues to increase and the mileage change value of the deceleration segment continues to decrease, it is determined that in the consistency test cycle, the driver is driving along the upper deviation of the vehicle speed during the acceleration segment and along the lower deviation of the vehicle speed during the deceleration segment;

[0042] 4) Analyze the engine speed data;

[0043] By comparing the engine speed data of the consistency test and the acceptance test, the test vehicle with higher engine speed also had relatively higher fuel consumption; the difference in fuel consumption can be obtained from the cumulative fuel consumption curve.

[0044] 5) Analyze the engine loss torque data;

[0045] Engine torque loss includes engine body losses and accessory losses; engine body losses include friction losses and pumping losses; accessory losses include compressor losses and generator losses; vehicles with high torque loss have relatively high fuel consumption; power loss is calculated based on torque loss and engine speed; from the beginning to a certain moment, the power loss is integrated over time to obtain the cumulative power loss at that moment; the curve of interest between cumulative power loss and time is defined as the cumulative power loss curve; subtracting the cumulative power loss curves of the conformity test and the acceptance test yields the trend curve of the cumulative power loss between the two tests; the rising segment of the curve indicates that the power loss of the conformity test is greater than that of the acceptance test within that time period, and the falling segment indicates that the power loss of the conformity test is less than that of the acceptance test within that time period;

[0046] 6) Analyze the engine crankshaft output torque data;

[0047] The crankshaft output torque is the combustion torque minus the loss torque. Vehicles with higher crankshaft output torque have relatively higher fuel consumption. The crankshaft output power is calculated based on the crankshaft output torque and engine speed. From the start to a certain moment, the crankshaft output power is integrated over time to obtain the cumulative crankshaft output power at that moment. The curve showing the relationship between the cumulative crankshaft output power and time is defined as the cumulative crankshaft output power curve. Subtracting the cumulative crankshaft output power curves from the consistency test and the acceptance test yields the trend curve of the cumulative crankshaft output power changes between the two tests. The rising segment of the curve indicates that the crankshaft output power in the consistency test is greater than that in the acceptance test during that time period, while the falling segment indicates that the crankshaft output power in the consistency test is less than that in the acceptance test during that time period.

[0048] 7) Analyze the engine coolant temperature data;

[0049] Compare engine coolant temperature data from consistency tests and acceptance tests. The time it takes for the coolant temperature to reach 80℃ is the engine warm-up time; test vehicles with longer warm-up times generally have higher fuel consumption.

[0050] 8) Analyze the deceleration fuel cut-off time data;

[0051] By comparing the deceleration fuel cut-off time data from the consistency test and the acceptance test, the test vehicle with a longer deceleration fuel cut-off time had relatively lower fuel consumption; the fuel consumption difference was calculated based on the cumulative fuel consumption trend curve.

[0052] 9) Analyze the gearbox gear position data;

[0053] By comparing the gearbox gear data from the consistency test and acceptance test, the engine speed was higher and the fuel consumption of the test vehicle was relatively higher under the condition of lower gear; the difference in fuel consumption was obtained based on the cumulative fuel consumption trend curve.

[0054] 10) Analyze engine load data;

[0055] Compare the generator load data of the conformance test and the acceptance test; the test vehicle with a higher generator load consumes more motor energy, and therefore consumes more fuel; the generator load signal fluctuates greatly, so the generator load signal is integrated over time; the integral value of the conformance test is subtracted from the integral value of the acceptance test to obtain the trend curve of motor load change over time; the rising part of the curve indicates that the motor load of the conformance test is greater than that of the acceptance test during the time period, and the falling part of the curve indicates that the motor load of the conformance test is less than that of the acceptance test during the time period.

[0056] 11) Analyze the battery SOC data;

[0057] The battery should be fully charged before the fuel consumption test. According to the vehicle leakage requirements, the battery SOC should be greater than 90% before the formal test; if the battery SOC is too low, the alternator will charge the battery during the test, resulting in increased fuel consumption.

[0058] The beneficial effects of this invention are as follows:

[0059] 1) This invention improves the efficiency of troubleshooting fuel consumption consistency issues, shortens the troubleshooting time, and reduces the workload of troubleshooting fuel consumption consistency issues;

[0060] 2) This invention conducts fuel consumption acceptance tests and fuel consumption consistency sampling tests in accordance with the fuel consumption consistency problem investigation process, and records CAN bus data, and determines the differences of each system or component in accordance with the process;

[0061] 3) According to the process and method of this invention, the cause of fuel consumption inconsistency can be determined by only one fuel consumption consistency verification test, which shortens the time for troubleshooting fuel consumption problems;

[0062] 4) This invention can quickly identify the area where fuel consumption consistency problems occur, saving the work of swapping subsystems or parts and repeatedly conducting fuel consumption tests, thus reducing the workload of troubleshooting fuel consumption problems. Attached Figure Description

[0063] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 This is a schematic diagram of the process of the present invention;

[0065] Figure 2 This is a schematic diagram illustrating the trend of fuel consumption changes;

[0066] Figure 3 This is a diagram showing the engine speed.

[0067] Figure 4 This is a schematic diagram of the engine's partial rotational speed.

[0068] Figure 5 This is a diagram of the gearbox gear positions;

[0069] Figure 6 This is a diagram illustrating the deceleration fuel cutoff mechanism.

[0070] Figure 7 This is a diagram illustrating the difference in vehicle mileage.

[0071] Figure 8 This is a diagram showing the engine coolant temperature.

[0072] Figure 9 This is a schematic diagram illustrating the power loss of the engine.

[0073] Figure 10 This is a schematic diagram of the power difference output from the engine crankshaft.

[0074] Figure 11 This is a schematic diagram of engine load. Detailed Implementation

[0075] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0076] Example 1

[0077] See Figure 1 A method for troubleshooting fuel consumption consistency issues in mass-produced vehicles includes the following steps:

[0078] Step 1: Inspect the fuel consumption test vehicles during the development phase;

[0079] The specific method is as follows:

[0080] The engine and transmission must be in the form of a C-sample or mass-produced part;

[0081] The engine and transmission control unit version numbers and calibration data numbers are in mass production status;

[0082] The tire pressure and model meet the requirements of the drawings;

[0083] The vehicle's four-wheel alignment parameters meet the drawing requirements; the battery's initial SOC is ≥90%, and the battery voltage is ≥12.3V;

[0084] The idle start-stop function is working normally.

[0085] The intake and exhaust systems are leak-proof;

[0086] The vehicle can enter a sleep mode after being locked.

[0087] The vehicle's fuel meets the requirements of the drawings;

[0088] The vehicle has no other fault codes affecting fuel consumption performance;

[0089] The break-in mileage for the vehicle should not exceed 300km.

[0090] If the inspection results do not meet the requirements, explanatory materials must be provided to ensure that the fuel consumption test results are not affected.

[0091] Step 2: Inspect the fuel consumption acceptance equipment during the development phase and set its parameters;

[0092] The specific method is as follows:

[0093] The technical specifications of the rotary drum testing equipment meet the requirements of the sixth stage of emission limits and measurement methods for pollutants from light-duty vehicles.

[0094] Vehicle immersion time ≥ 6 hours;

[0095] The laboratory temperature was 23±5℃;

[0096] The vehicle's coasting curve used in the test shall be based on the values ​​in the test report.

[0097] Before the fuel consumption test, the vehicle should undergo a coasting test on the rotating drum to determine the drum loading curve.

[0098] Step 3: Record fuel consumption acceptance test data during the development phase;

[0099] The specific method is as follows:

[0100] Before the fuel consumption test, the CAN bus device is started, and PT-CAN bus data is recorded during the test. The test data includes: fuel cut-off status, engine start / stop status, engine speed, air conditioning AC switch status, brake pedal status, torque without TCU request, throttle opening, accelerator opening, air conditioning compressor request, target gear, actual gear, cooling fan duty cycle, ambient temperature, wheel speed of all four wheels, vehicle speed, driver's seat belt status, lost torque, combustion torque, TCU requested torque, TCU speed request, DCT pressure plate speed, DCT output shaft speed, instantaneous fuel consumption, engine coolant temperature, battery SOC, battery SOC status, generator load, transmission operating mode, and total mileage.

[0101] Step 4: Inspect the fuel consumption consistency test vehicle, inspect the test equipment, set the equipment parameters, and record the data;

[0102] The specific method is as follows:

[0103] Conduct vehicle inspections for consistency testing, check and set parameters for the rotating equipment, refer to the fuel consumption acceptance test, and record PT-CAN bus data.

[0104] Step 5: Investigate fuel consumption consistency issues;

[0105] The specific method is as follows:

[0106] Based on the vehicle speed signal, the time start point of the CAN bus data for the acceptance test and conformance test is aligned as follows:

[0107] 1) Analyze the issue of fuel consumption consistency;

[0108] Based on the trend of vehicle fuel consumption changes, the time period during which fuel consumption increases in the consistency fuel consumption test is determined. During the time period during which fuel consumption increases in the consistency fuel consumption test, the differences in transmission gear position, deceleration section oil level, engine speed, vehicle speed, engine coolant temperature, battery SOC change, engine torque loss, engine crankshaft output torque, and generator load are analyzed. Through the above analysis, the direction for troubleshooting fuel consumption consistency issues is clarified, and each system or component conducts further analysis and troubleshooting for the problems found.

[0109] 2) Analyze instantaneous fuel consumption data;

[0110] Instantaneous fuel consumption is defined as the total amount of fuel injected by the engine within 0.1 seconds; cumulative fuel consumption is defined as the total amount of fuel injected by the engine from the start of the test to a certain moment, i.e., the total instantaneous fuel consumption within that time period; the curve relating cumulative fuel consumption to time is defined as the cumulative fuel consumption curve; subtracting the cumulative fuel consumption curves of the consistency test and the acceptance test yields the fuel consumption trend curve of the vehicle in the consistency test relative to the acceptance test; the rising segment of the curve indicates that the fuel consumption in the consistency test is greater than that in the acceptance test within that time period, and the falling segment indicates that the fuel consumption in the consistency test is less than that in the acceptance test within that time period; by investigating other signals within that time period, the cause of the fuel consumption change is determined;

[0111] 3) Analyze the vehicle speed data;

[0112] From the start to a certain moment, the vehicle speed is integrated over time to obtain the vehicle's mileage at that moment; the relationship curve between mileage and time is defined as the mileage curve; the mileage curves of the consistency test and the acceptance test are subtracted to obtain the mileage change trend curves of the two tests; the rising segment of the curve indicates that the mileage of the consistency test is greater than that of the acceptance test within that time period, and the falling segment indicates that the mileage of the consistency test is less than that of the acceptance test within that time period; when the mileage change value of the acceleration segment continuously increases and the mileage change value of the deceleration segment continuously decreases, it is determined that in the consistency test cycle, the driver is driving along the upper deviation of vehicle speed during the acceleration segment and along the lower deviation of vehicle speed during the deceleration segment; although the total mileage of the two tests is similar, fuel is injected during the acceleration segment and cut off during the deceleration segment. This will lead to an increase in fuel consumption in the consistency test, and this difference in fuel consumption is caused by driver operation deviation;

[0113] 4) Analyze the engine speed data;

[0114] By comparing the engine speed data of the consistency test and the acceptance test, the test vehicle with higher engine speed also had relatively higher fuel consumption; the difference in fuel consumption can be obtained from the cumulative fuel consumption curve.

[0115] 5) Analyze the engine loss torque data;

[0116] Engine torque loss includes engine body losses and accessory losses; engine body losses include friction losses and pumping losses; accessory losses include compressor losses and generator losses; vehicles with high torque loss have relatively high fuel consumption; power loss is calculated based on torque loss and engine speed; from the beginning to a certain moment, the power loss is integrated over time to obtain the cumulative power loss at that moment; the curve of interest between cumulative power loss and time is defined as the cumulative power loss curve; subtracting the cumulative power loss curves of the conformity test and the acceptance test yields the trend curve of the cumulative power loss between the two tests; the rising segment of the curve indicates that the power loss of the conformity test is greater than that of the acceptance test within that time period, and the falling segment indicates that the power loss of the conformity test is less than that of the acceptance test within that time period;

[0117] 6) Analyze the engine crankshaft output torque data;

[0118] The crankshaft output torque is the combustion torque minus the loss torque. Vehicles with higher crankshaft output torque have relatively higher fuel consumption. The crankshaft output power is calculated based on the crankshaft output torque and engine speed. From the start to a certain moment, the crankshaft output power is integrated over time to obtain the cumulative crankshaft output power at that moment. The curve showing the relationship between the cumulative crankshaft output power and time is defined as the cumulative crankshaft output power curve. Subtracting the cumulative crankshaft output power curves from the consistency test and the acceptance test yields the trend curve of the cumulative crankshaft output power changes between the two tests. The rising segment of the curve indicates that the crankshaft output power in the consistency test is greater than that in the acceptance test during that time period, while the falling segment indicates that the crankshaft output power in the consistency test is less than that in the acceptance test during that time period.

[0119] 7) Analyze the engine coolant temperature data;

[0120] Compare engine coolant temperature data from consistency tests and acceptance tests. The time it takes for the coolant temperature to reach 80℃ is the engine warm-up time; test vehicles with longer warm-up times generally have higher fuel consumption.

[0121] 8) Analyze the deceleration fuel cut-off time data;

[0122] By comparing the deceleration fuel cut-off time data from the consistency test and the acceptance test, the test vehicle with a longer deceleration fuel cut-off time had relatively lower fuel consumption; the fuel consumption difference was calculated based on the cumulative fuel consumption trend curve.

[0123] 9) Analyze the gearbox gear position data;

[0124] By comparing the gearbox gear data from the consistency test and acceptance test, the engine speed was higher and the fuel consumption of the test vehicle was relatively higher under the condition of lower gear; the difference in fuel consumption was obtained based on the cumulative fuel consumption trend curve.

[0125] 10) Analyze engine load data;

[0126] Compare the generator load data of the conformance test and the acceptance test; the test vehicle with a higher generator load consumes more motor energy, and therefore consumes more fuel; the generator load signal fluctuates greatly, so the generator load signal is integrated over time; the integral value of the conformance test is subtracted from the integral value of the acceptance test to obtain the trend curve of motor load change over time; the rising part of the curve indicates that the motor load of the conformance test is greater than that of the acceptance test during the time period, and the falling part of the curve indicates that the motor load of the conformance test is less than that of the acceptance test during the time period.

[0127] 11) Analyze the battery SOC data;

[0128] The battery should be fully charged before the fuel consumption test; according to the vehicle leakage requirements, the battery SOC should be greater than 90% before the formal test; if the battery SOC is too low, the generator will charge the battery during the test, which will lead to increased fuel consumption.

[0129] Example 2

[0130] This example uses the Besturn B70 15T production vehicle as an example to investigate the issue of consistent fuel consumption:

[0131] 1. Following steps 1-4 in Example 1, conduct fuel consumption test vehicle inspections, test equipment inspections, equipment parameter settings, and data recording for a certain vehicle model during both the development and mass production stages. The test results show that the fuel consumption consistency test results for the mass-produced vehicle are 0.2L / 100km higher than the announced value.

[0132] 2. Follow step five in Example 1 to investigate fuel consumption consistency issues.

[0133] 2.1 Instantaneous fuel consumption data analysis. Figure 2 The graph shows the fuel consumption trend curve, specifically the difference between consistent cumulative fuel consumption and acceptance cumulative fuel consumption. As can be seen from the graph, the fuel consumption difference increases for each idle stop condition between 0 and 800 seconds. Figure 3 For engine speed data, Figure 4 This is partial engine speed data. From... Figure 4 As shown in the red circle, before the engine idles and stops, the engine speed in the mass-produced vehicle increases from 850 rpm to 1200 rpm. Combined with... Figure 2 It can be seen that this increase in engine speed leads to increased fuel consumption. After confirmation with the transmission specialists, it was found that the optimized speed control strategy, implemented to address drivability issues, resulted in an increase in engine speed before shutdown.

[0134] 2.2 Gearbox gear data analysis. Figure 5 The graph shows the gear shift curves for the transmission. As can be seen from the graph, the gear shifts in the development verification test and the conformance test are basically the same.

[0135] 2.3 Analysis of deceleration fuel cut-off data. Figure 6 As shown in the deceleration fuel cut-off curve, the fuel cut-off time during the deceleration phase of the vehicle in the consistency test is longer than that in the acceptance test, so it will not lead to an increase in fuel consumption.

[0136] 2.4 Vehicle speed data analysis. Figure 7 The curve showing the difference in vehicle mileage is obtained by integrating vehicle speed over time. As shown in the figure, the mileage of the consistency test vehicle is less than that of the verification test vehicle; therefore, the driver's operation during the consistency test did not lead to an increase in fuel consumption.

[0137] 2.5 Engine coolant temperature data analysis. Figure 8This is the engine coolant temperature profile. The conformance test vehicle reached 80°C in 537 seconds, while the acceptance test vehicle did so in 470 seconds. 80°C is the engine warm-up temperature; the shorter the time to reach this temperature, the lower the engine warm-up fuel consumption. The conformance verification vehicle's warm-up time increased by 67 seconds, resulting in increased fuel consumption.

[0138] 2.6 Analysis of lost torque data. Figure 9 The figure shows the difference curve of engine power loss. As can be seen from the figure, the engine power loss of the consistency test vehicle is less than that of the verification test vehicle, therefore the engine torque loss does not lead to an increase in fuel consumption.

[0139] 2.7 Crankshaft output torque data analysis. Figure 10 The figure shows the difference curve of engine crankshaft output power. As can be seen from the figure, the crankshaft output power of the engine in the consistency test vehicle is less than that in the verification test vehicle. Therefore, the engine crankshaft output torque does not lead to an increase in fuel consumption.

[0140] 2.8 Generator load data analysis. Figure 11 The figure shows the generator load curve. As can be seen, the generator load of the conformity test vehicle is significantly higher than that of the acceptance test vehicle. This higher generator load leads to increased fuel consumption.

[0141] In summary, this invention requires only one fuel consumption consistency verification test to determine the cause of fuel consumption problems, thus shortening the time for troubleshooting fuel consumption problems; it can also quickly identify the area where fuel consumption consistency problems occur, eliminating the need to swap subsystems or parts and repeatedly conduct fuel consumption tests, thereby reducing the workload of troubleshooting fuel consumption problems.

[0142] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for troubleshooting fuel consumption consistency issues in mass-produced vehicles, characterized in that, Includes the following steps: Step 1: Inspect the fuel consumption test vehicles during the development phase; Step 2: Inspect the fuel consumption acceptance equipment during the development phase and set its parameters; Step 3: Record fuel consumption acceptance test data during the development phase; Step 4: Inspect the fuel consumption consistency test vehicle, inspect the test equipment, set the equipment parameters, and record the data; Step 5: Investigate fuel consumption consistency issues; The specific method for step five is as follows: Based on the vehicle speed signal, the time start point of the CAN bus data for the acceptance test and conformance test is aligned as follows: 1) Analyze the issue of fuel consumption consistency; Based on the trend of vehicle fuel consumption changes, the time period during which fuel consumption increases in the consistency fuel consumption test is determined. During the time period during which fuel consumption increases in the consistency fuel consumption test, the differences in transmission gear position, deceleration section oil level, engine speed, vehicle speed, engine coolant temperature, battery SOC change, engine torque loss, engine crankshaft output torque, and generator load are analyzed. Through the above analysis, the direction for troubleshooting fuel consumption consistency issues is clarified, and each system or component conducts further analysis and troubleshooting for the problems found. 2) Analyze instantaneous fuel consumption data; Instantaneous fuel consumption is defined as the total amount of fuel injected by the engine within 0.1 seconds; cumulative fuel consumption is defined as the total amount of fuel injected by the engine from the start of the test to a certain moment, i.e., the total instantaneous fuel consumption within that time period; the curve relating cumulative fuel consumption to time is defined as the cumulative fuel consumption curve; subtracting the cumulative fuel consumption curves of the consistency test and the acceptance test yields the fuel consumption trend curve of the vehicle in the consistency test relative to the acceptance test; the rising segment of the curve indicates that the fuel consumption in the consistency test is greater than that in the acceptance test within that time period, and the falling segment indicates that the fuel consumption in the consistency test is less than that in the acceptance test within that time period; by investigating other signals within that time period, the cause of the fuel consumption change is determined; 3) Analyze the vehicle speed data; From the start to a certain moment, the vehicle speed is integrated over time to obtain the vehicle's mileage at that moment; the relationship curve between mileage and time is defined as the mileage curve; the mileage curves of the consistency test and the acceptance test are subtracted to obtain the mileage change trend curves of the two tests; the rising segment of the curve indicates that the mileage of the consistency test is greater than that of the acceptance test within that time period, and the falling segment indicates that the mileage of the consistency test is less than that of the acceptance test within that time period; when the mileage change value of the acceleration segment continues to increase and the mileage change value of the deceleration segment continues to decrease, it is determined that in the consistency test cycle, the driver is driving along the upper deviation of the vehicle speed during the acceleration segment and along the lower deviation of the vehicle speed during the deceleration segment; 4) Analyze the engine speed data; By comparing the engine speed data of the consistency test and the acceptance test, the test vehicle with higher engine speed also had relatively higher fuel consumption; the difference in fuel consumption can be obtained from the cumulative fuel consumption curve. 5) Analyze the engine loss torque data; Engine torque loss includes engine body losses and accessory losses; engine body losses include friction losses and pumping losses; accessory losses include compressor losses and generator losses; vehicles with high torque loss have relatively high fuel consumption; power loss is calculated based on torque loss and engine speed; from the beginning to a certain moment, the power loss is integrated over time to obtain the cumulative power loss at that moment; the curve of interest between cumulative power loss and time is defined as the cumulative power loss curve; subtracting the cumulative power loss curves of the conformity test and the acceptance test yields the trend curve of the cumulative power loss between the two tests; the rising segment of the curve indicates that the power loss of the conformity test is greater than that of the acceptance test within that time period, and the falling segment indicates that the power loss of the conformity test is less than that of the acceptance test within that time period; 6) Analyze the engine crankshaft output torque data; The crankshaft output torque is the combustion torque minus the loss torque; vehicles with higher crankshaft output torque have relatively higher fuel consumption. The crankshaft output power is calculated based on the crankshaft output torque and engine speed. From the start to a certain moment, the crankshaft output power is integrated over time to obtain the cumulative crankshaft output power at that moment. The curve relating the cumulative crankshaft output power to time is defined as the cumulative crankshaft output power curve. Subtracting the cumulative crankshaft output power curves from the consistency test and the acceptance test yields the trend curve of the cumulative crankshaft output power changes between the two tests. The rising segment of the curve indicates that the crankshaft output power in the consistency test is greater than that in the acceptance test within that time period, and the falling segment indicates that the crankshaft output power in the consistency test is less than that in the acceptance test within that time period. 7) Analyze the engine coolant temperature data; Compare engine coolant temperature data from consistency tests and acceptance tests; the time it takes for the coolant temperature to reach 80℃ is the engine warm-up time; test vehicles with longer warm-up times have relatively higher fuel consumption. 8) Analyze the deceleration fuel cut-off time data; By comparing the deceleration fuel cut-off time data from the consistency test and the acceptance test, the test vehicle with a longer deceleration fuel cut-off time had relatively lower fuel consumption; the fuel consumption difference was calculated based on the cumulative fuel consumption trend curve. 9) Analyze the gearbox gear position data; By comparing the gearbox gear data from the consistency test and acceptance test, the engine speed was higher and the fuel consumption of the test vehicle was relatively higher under the condition of lower gear; the difference in fuel consumption was obtained based on the cumulative fuel consumption trend curve. 10) Analyze engine load data; Compare the generator load data of the conformance test and the acceptance test; the test vehicle with a higher generator load consumes more motor energy, and therefore consumes more fuel; the generator load signal fluctuates greatly, so the generator load signal is integrated over time; the integral value of the conformance test is subtracted from the integral value of the acceptance test to obtain the trend curve of motor load change over time; the rising part of the curve indicates that the motor load of the conformance test is greater than that of the acceptance test during the time period, and the falling part of the curve indicates that the motor load of the conformance test is less than that of the acceptance test during the time period. 11) Analyze the battery SOC data; The battery should be fully charged before the fuel consumption test; according to the vehicle leakage requirements, the battery SOC should be greater than 90% before the formal test; if the battery SOC is too low, the generator will charge the battery during the test, resulting in increased fuel consumption.

2. The method for troubleshooting fuel consumption consistency issues in mass-produced vehicles according to claim 1, characterized in that, The specific method for step one is as follows: The engine and transmission must be in the form of a C-sample or mass-produced part; The engine and transmission control unit version numbers and calibration data numbers are in mass production status; The tire pressure and model meet the requirements of the drawings; The vehicle's four-wheel alignment parameters meet the drawing requirements; the battery's initial SOC is ≥90%, and the battery voltage is ≥12.3V; The idle start-stop function is working normally. The intake and exhaust systems are leak-proof; The vehicle can enter a sleep mode after being locked. The vehicle's fuel meets the requirements of the drawings; The vehicle has no other fault codes affecting fuel consumption performance; The break-in mileage for the vehicle should not exceed 300km.

3. The method for troubleshooting fuel consumption consistency issues in mass-produced vehicles according to claim 2, characterized in that, If the inspection results do not meet the requirements, explanatory materials must be provided.

4. The method for troubleshooting fuel consumption consistency issues in mass-produced vehicles according to claim 1, characterized in that, The specific method for step two is as follows: The technical specifications of the rotary drum testing equipment meet the requirements of the sixth stage of emission limits and measurement methods for pollutants from light-duty vehicles. Vehicle immersion time ≥ 6 hours; The laboratory temperature was 23±5℃; The vehicle's coasting curve used in the test shall be based on the values ​​in the test report. Before the fuel consumption test, the vehicle should undergo a coasting test on the rotating drum to determine the drum loading curve.

5. The method for troubleshooting fuel consumption consistency issues in mass-produced vehicles according to claim 1, characterized in that, The specific method for step three is as follows: Before the fuel consumption test, the CAN bus device is started, and PT-CAN bus data is recorded during the test. The test data includes: fuel cut-off status, engine start / stop status, engine speed, air conditioning AC switch status, brake pedal status, torque without TCU request, throttle opening, accelerator opening, air conditioning compressor request, target gear, actual gear, cooling fan duty cycle, ambient temperature, wheel speed of all four wheels, vehicle speed, driver's seat belt status, lost torque, combustion torque, TCU requested torque, TCU speed request, DCT pressure plate speed, DCT output shaft speed, instantaneous fuel consumption, engine coolant temperature, battery SOC, battery SOC status, generator load, transmission operating mode, and total mileage.

6. The method for troubleshooting fuel consumption consistency issues in mass-produced vehicles according to claim 1, characterized in that, The specific method for step four is as follows: Conduct vehicle inspections for consistency testing, check and set parameters for the rotating equipment, refer to the fuel consumption acceptance test, and record PT-CAN bus data.

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