A fuel-saving test method and recording medium for electronically controlled air compressor

Abstract

The present invention belongs to the technical field of engine test, and particularly relates to a fuel-saving test method for an electronically controlled air compressor, including obtaining basic data of a vehicle fuel consumption cycle test working condition, determining the braking time point, duration and braking air consumption; inputting relevant data into an engine bench test control system, so that the working conditions of the engine bench test and the vehicle fuel consumption cycle test are consistent; configuring an electronically controlled air compressor working in a mechanical mode as a brake air source in the engine bench test, and measuring the fuel consumption of the electronically controlled air compressor working in the mechanical mode; then measuring the fuel consumption of the electronically controlled air compressor configured under various other control strategies and making a comparison, and obtaining the fuel saving rate of the electronically controlled air compressor relative to the mechanical air compressor in the vehicle fuel consumption cycle test process under different control strategies. The present invention also provides a medium storing the method program. The present invention overcomes the problem that it is difficult to accurately measure a small fuel saving rate due to human error on the bench, and is suitable for engine bench fuel saving tests.

Description

Technical Field

[0001] The invention belongs to the technical field of engine test and discloses a fuel-saving test method for an electronically controlled air compressor and a recording medium storing a program capable of executing the method. Background Art

[0002] The fuel consumption of a vehicle is an economic technical indicator of the vehicle. Lower fuel consumption is beneficial to environmental protection and energy conservation, and can also better reflect the competitiveness of the vehicle product. At present, electronic control of engine accessories is an important technical measure for engine fuel saving. For example, the electronically controlled water pump, electronically controlled oil pump, and electronically controlled air compressor attached to the engine can save more fuel and reduce consumption than conventional mechanical control components.

[0003] The factors affecting the fuel efficiency of the electric air compressor under different control strategies are mainly the actual working time of the electric air compressor under different control strategies. The longer the working time, the more fuel the electric air compressor consumes to replenish the air tank, and the more fuel the mechanical friction of the air compressor consumes. However, the fuel saving rate between different control strategies of the general electric air compressor is only less than 3% in the NEDC cycle fuel consumption of the whole vehicle or other fuel consumption regulations cycle tests such as C-WTVC. The fuel consumption measurement equipment itself will also have a certain measurement error. In addition, there are certain differences in the fuel consumption cycle conditions of the whole vehicle and the driver's braking driving habits during each measurement. It is difficult to accurately test the fuel saving rate in such a narrow range. For example, the patent with announcement number CN104964827A: "A method for calculating idle fuel saving rate" is based on the NEDC road cycle of the whole vehicle. The fuel saving rate is approximately deduced by converting the average fuel consumption values ​​at different engine idle speeds over a long period of time into the NEDC cycle fuel consumption of the whole vehicle. The reason for adopting this method of converting fuel consumption is mainly because the difference in fuel consumption at different idle speeds is small, and the idle condition accounts for a small proportion of the time in the NEDC condition. However, this method is not suitable for conditions in cities where vehicles often stop and idle due to traffic lights. Announcement No. CN 105628392 A: The method in the patent "A method for calculating the fuel saving rate of a start-stop system" is based on the NEDC road cycle. It adopts a formula and uses the vehicle NEDC measured data, calibrated theoretical fuel volume data and empirical data (idle fuel consumption correction coefficient Φn, start-up enriched fuel consumption Fstart) to calculate the fuel saving rate of the engine start-stop system. Obviously, the correction coefficient Φn is difficult to determine, and the patent does not disclose the method for determining Φn; therefore, it is also difficult to derive the accurate fuel saving rate of the NEDC operating condition. Summary of the invention

[0004] In view of the above problems, the present invention provides a fuel saving test method for an electronically controlled air compressor, and the specific scheme includes the following steps:

[0005] P1. Carry out a vehicle fuel consumption cycle test to obtain basic data of the vehicle fuel consumption cycle test conditions, the basic data including engine speed, engine torque, brake chamber pressure at different times under the vehicle fuel consumption cycle conditions and their corresponding relationship;

[0006] P2. Determine the braking time point, braking duration and brake chamber pressure through the curve of the brake chamber pressure changing with time;

[0007] P3. Input the braking time point, braking duration, brake chamber pressure and the basic data into the engine bench test control system, so that the engine state and brake system gas state of the engine bench test are consistent with the engine state and brake system gas state of the vehicle fuel consumption cycle test;

[0008] P4. In the engine bench test, configure the electronically controlled air compressor to work in mechanical mode (simulating a mechanical air compressor) as the brake air source and measure the fuel consumption during the entire test duration;

[0009] P5. In the engine bench test, configure the electronically controlled air compressor to work as the brake air source under different electronic control strategies, and measure the fuel consumption under each control strategy during the entire test duration;

[0010] P6. Compare the fuel consumption under each control strategy measured in step P5 with the fuel consumption measured in step P4, and obtain the fuel saving rate of the electronically controlled air compressor under each control strategy relative to the mechanical air compressor during the fuel consumption cycle test.

[0011] The above method can better transplant the working conditions of the vehicle fuel consumption cycle test to the engine test bench through the extraction of key basic data, which is convenient for conducting fuel saving rate tests for different control strategies of the electronically controlled air compressor under the condition of consistent working conditions and compliance with industry testing standards.

[0012] Preferably, step P3 includes a step of using proportional-integral-differential (PID) control to achieve the consistency of the operating conditions.

[0013] This procedure for achieving consistent operating conditions uses closed-loop control. When various sensors and servo systems are sensitive, it can accurately simulate the action of the driver stepping on the brake pedal on the laboratory engine test bench to reproduce the operating conditions of the vehicle fuel consumption cycle test.

[0014] Preferably, step P3 includes a step of achieving the consistency of the working conditions by pushing the brake pedal at a uniform speed during braking.

[0015] This procedure to achieve consistent operating conditions only considers the braking point and braking duration, simplifies the braking speed to a uniform speed, reduces possible fault defects caused by too many components, and more importantly, eliminates the lag phenomenon in the closed-loop control that may cause fuel consumption deviations due to the non-coincidence of the actual pressure curves of the brake chamber in multiple tests.

[0016] Another embodiment of the present invention is to provide a non-transitory readable recording medium for storing one or more programs including a plurality of instructions. When the instructions are executed, the processing circuit will execute the above-mentioned fuel saving test method for the electronically controlled air compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a diagram showing the corresponding relationship between the vehicle speed and the engine speed under the C-WTVC working condition in an embodiment of the present invention;

[0018] Figure 2 : is a diagram showing the corresponding relationship between engine speed and torque under C-WTVC working condition in an embodiment of the present invention;

[0019] Figure 3 : is a graph showing the corresponding relationship between the engine speed and the brake chamber pressure under the C-WTVC working condition in an embodiment of the present invention;

[0020] Figure 4 Schematic diagram of different control strategies for an electronically controlled air compressor in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making innovative efforts are within the scope of protection of the present invention.

[0022] 1. Vehicle preparation before testing

[0023] Replace the electronically controlled air compressor on the vehicle, install the pressure sensor on the brake air chamber of the vehicle, electrically connect the controller with the electronically controlled air compressor, pressure sensor, relay and vehicle battery to ensure that the controller can normally control the operation of the electronically controlled air compressor and read the value of the pressure sensor.

[0024] The controller drives the relay to close normally, so that the electronic air compressor is in the working mode of a conventional mechanical air compressor. Before the test, make sure that the brake system air tank is full of air.

[0025] 2. Acquisition of basic data of vehicle fuel consumption cycle and recording of test parameters

[0026] There are two ways and methods to obtain the basic data of vehicle fuel consumption cycle conditions. One is to conduct a vehicle fuel consumption regulation cycle test on a vehicle hub test bench according to the vehicle fuel consumption regulation cycle (such as NEDC, C-WTVC and other fuel consumption regulation cycles); the other is to use the actual vehicle road to collect road spectrum parameters. The road conditions can cover 40% of urban conditions, 40% of suburban or rural conditions, and 30% of high-speed conditions. The specific distribution ratio of conditions can be determined according to the application market environment of the vehicle. Which method is selected as the basic data of the vehicle fuel consumption cycle condition as the fuel saving efficiency test of different control strategies of the electronic air compressor depends on the company's own development purpose. Therefore, the vehicle fuel consumption cycle condition scheme can be freely selected. Which method is used for road spectrum parameter collection can be applied to the subsequent scheme description of the patent of this invention; this patent simplifies the subsequent test scheme description and is unified as the vehicle C-WTVC condition fuel consumption regulation cycle.

[0027] The relay is normally closed to ensure that the electronically controlled air compressor is always in working condition during the vehicle hub C-WTVC working condition fuel consumption test, that is, the electronically controlled air compressor is in the working mode of a conventional mechanical air compressor during the test.

[0028] When the C-WTVC fuel consumption regulation cycle is carried out on the vehicle's rotating hub, when the vehicle's rotating hub dynamometer enters the C-WTVC condition, the controller is triggered through the rotating hub dynamometer control system to record the pressure value of the brake air chamber pressure sensor; by monitoring the pressure value of the pressure sensor, the driver's braking point, braking duration and brake air chamber pressure (corresponding to the braking depth of the brake pedal) in the vehicle's C-WTVC condition can be known.

[0029] At the same time, the engine speed (OBD_EngineSpeed), engine torque (OBD_RealTorque) and vehicle speed (vehicle Speed) in the vehicle ECU are read and recorded at a frequency of 1 Hz through the vehicle OBD terminal interface, and the engine speed parameter and engine torque parameter table of 1800s can be obtained as the operating condition of the engine test bench C-WTVC; the pressure value of the pressure sensor on the brake chamber is superimposed on the speed and torque list of the engine C-WTVC, and the corresponding relationship between the engine speed, torque and the pressure of the brake chamber of the brake system can be obtained, as shown in Table 1.

[0030] Table 1: Engine speed, torque and brake chamber pressure

[0031]

[0032]

[0033] 3. Transplantation of working conditions from vehicle to test bench and preparation for fuel saving test of electronically controlled air compressor test bench

[0034] The basic engine data of the vehicle fuel consumption cycle test conditions obtained in the above steps and the information on braking time, braking duration and brake chamber pressure (corresponding to the braking depth of the brake pedal) are input into the engine bench test control system as the basic data for the engine bench to perform C-WTVC. The fuel saving efficiency comparison test of any electronically controlled air compressor under different control strategies is carried out on this basic data.

[0035] Before conducting the C-WTVC test on the engine bench, the electronically controlled air compressor is installed on the engine, and the components related to the vehicle braking system (air dryer assembly, four-protection valve, air reservoir, brake pedal, quick release valve assembly, front / rear axle assembly, etc.) and the pedal displacement actuator (used to push the brake pedal according to the instructions issued by the control system) are arranged in the engine test room and electrically connected to the engine bench test control system.

[0036] The engine bench test control system can control the engine operation according to the working conditions introduced above, and control the brake pedal displacement actuator to push the brake pedal according to the brake air chamber pressure value. The brake pedal displacement actuator can perform PID feedback of the brake air chamber pressure signal through the brake air chamber pressure sensor, or the brake pedal displacement actuator adopts a scheme that only considers the braking time point and braking duration and simplifies the braking speed to a uniform speed (the speed of the brake pedal displacement actuator uniform speed scheme is determined by detecting the speed at which the driver steps on the brake pedal during the vehicle fuel consumption cycle and taking the average value).

[0037] 4. Engine Bench C-WTVC Fuel Consumption Test

[0038] Since the fuel consumption test of the electronically controlled air compressor under different control strategies cannot be completed within one day, the factors affecting the fuel consumption results need to be checked before each test.

[0039] It includes checking engine control conditions, such as engine water temperature, oil temperature, intake temperature, intake pressure, intercooler temperature, intercooler pressure, exhaust temperature, exhaust pressure, fuel consumption at rated power and other engine operating parameters to ensure that the engine status is consistent each time the engine undergoes the C-WTVC fuel consumption test; ensuring that the air tank is full during each test; checking the zero and full points of the fuel consumption meter to ensure that the zero and full point status of the fuel consumption meter are consistent each time the engine undergoes the C-WTVC fuel consumption test.

[0040] For the engine bench test corresponding to each electronically controlled air compressor control strategy, the C-WTVC operating condition is run continuously for no less than 3 times. After the test, the average value of multiple C-WTVC test fuel consumption is calculated as the C-WTVC test fuel consumption under the current electronically controlled air compressor control strategy.

[0041] The most basic fuel-saving control strategy for an electronically controlled air compressor is to control the lower pressure limit of the air tank. When the pressure of the air tank is lower than the set value, the electronically controlled air compressor starts to run to replenish the air in the air tank until it is full and then stops working. However, in addition to this most basic fuel-saving control strategy, electronically controlled air compressors also have other fuel-saving control strategies, such as controlling the upper pressure limit of the air tank, or controlling the number of times the unloading pressure of the brake system unloading valve is opened, etc. Figure 4 The control strategy above is the normally closed state of the electronically controlled air compressor, which simulates the working state of a conventional mechanical air compressor. Figure 4 The middle control strategy is to control the lower limit of the gas tank pressure. Figure 4 The control strategy below is to control the upper and lower limits of the air tank pressure and the number of times the brake system unloading valve is opened. Different types of control strategies will have different fuel-saving effects, and the same type of control strategy will also bring different fuel-saving effects due to different parameter settings; Table 2 below is a C-WTVC engine bench test fuel consumption record table of the electronic air compressor under different control strategies. Comparing the fuel consumption of each strategy in Table 2 with S1 can obtain the corresponding fuel saving rate of different control strategies.

[0042] Table 2: Different control strategies for electronically controlled air compressors

[0043]

[0044]

[0045] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computers, available storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0046] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0047] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0048] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0049] Compiling the above method steps into a program and then storing it in a hard disk or other non-transitory storage medium constitutes the technical solution of "a non-transitory readable recording medium" of the present invention.

[0050] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fuel saving test method for an electronically controlled air compressor, characterized in that The following steps are involved: P1. Carry out a vehicle fuel consumption cycle test to obtain basic data of the vehicle fuel consumption cycle test conditions, the basic data including engine speed, engine torque, brake chamber pressure at different times and their corresponding relationships; P2. Determine the braking time, braking duration and braking air consumption by the change of the pressure of the brake chamber over time; P3. Input the braking time point, braking duration, braking gas consumption and the basic data into the engine bench test control system so that the engine bench test is consistent with the vehicle fuel consumption cycle test conditions; P4. In the engine bench test, an electronically controlled air compressor operating in mechanical mode is configured as the brake air source, and the fuel consumption during the entire test duration is measured; P5. In the engine bench test, an electronically controlled air compressor operating under different electronic control strategies is configured as the brake air source, and the fuel consumption during the entire test duration is measured; P6. Compare the fuel consumption data under each control strategy measured in step P5 with the fuel consumption measured in step P4, and obtain the fuel saving rate of the electronically controlled air compressor under each control strategy relative to the mechanical air compressor during the vehicle fuel consumption cycle test.

2. A fuel saving test method for an electronically controlled air compressor as claimed in claim 1, characterized in that Step P3 includes the step of controlling the brake pedal using a proportional-integral-differential (PID) control method to achieve the consistent working conditions.

3. A fuel saving test method for an electronically controlled air compressor as claimed in claim 1, characterized in that Step P3 includes the step of controlling the brake pedal to achieve the consistent working condition by pushing the brake pedal at a constant speed during braking.

4. A non-transitory readable recording medium for storing one or more programs including a plurality of instructions, characterized in that: When the instruction is executed, the processing circuit will be caused to execute the fuel-saving test method for an electronically controlled air compressor according to any one of claims 1 to 3.

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