A fuel-saving bench test device for electronically controlled air compressors

Abstract

The present invention belongs to the technical field of engine testing, and particularly relates to a fuel-saving bench test device for an electronically controlled air compressor, comprising an electronically controlled air compressor brake air circuit system with a controller and a bench measurement and control system. The bench measurement and control system can receive vehicle fuel consumption cycle test data, and control the engine and brake pedal to operate according to the working conditions of the vehicle fuel consumption cycle test accordingly. The present invention overcomes the problem that it is difficult to accurately measure a tiny fuel saving rate due to human error on the bench, and is suitable for engine bench fuel saving testing.

Description

Technical Field

[0001] The invention belongs to the technical field of engine test and discloses a fuel-saving bench test device for an electronically controlled air compressor. 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-saving 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. At the same time, the mechanical friction of the air compressor also consumes more fuel. However, the fuel saving rate between different control strategies of general electronic air compressors is only less than 3% in NEDC cycle fuel consumption or other fuel consumption regulation cycle tests such as C-WTVC. When testing the fuel consumption level of electronic air compressors on a vehicle road or a vehicle hub dynamometer, even if the same driver has different braking duration and braking timing during each test, the fuel consumption test will be different. The difference will be even greater when different drivers operate, and the resulting error may even exceed 3%. In addition, fuel consumption cycle tests on engine benches are conducted to avoid the influence of human factors. Although theoretically it can solve the problems of test errors and poor repeatability, it is difficult to implement. The main problems are how to control the vehicle brake pedal, how to synchronize the brake pedal control signal and the test condition data, etc. Therefore, electronic air compressor manufacturers and vehicle manufacturers are unable to come up with real data on the fuel saving of electronic air compressors in engineering applications. Summary of the invention

[0004] In view of the above problems, the present invention provides a fuel-saving bench test device for an electronically controlled air compressor, comprising an electrically connected vehicle battery 9, a relay 7, a controller 8, and an air tank 2, a brake air chamber 4, a brake pedal 3 and an electronically controlled air compressor 1 connected through a pipeline, wherein a pressure sensor 5 is installed on the air tank 2, and a pressure sensor 6 is installed on the brake air chamber 4. The controller 8 can receive information sent back by the pressure sensors 5 and 6 and control the start and stop of the electronically controlled air compressor 1 through the relay 7. The device also includes a brake pedal displacement actuator 10 installed above the brake pedal 3, a bench measurement and control system 11, and a motor forward and reverse controller 12. The bench measurement and control system 11 can receive vehicle fuel consumption cycle test data, and control the engine to operate according to the working conditions of the vehicle fuel consumption cycle test accordingly, and control the brake pedal displacement actuator 10 to move through the motor forward and reverse controller 12, thereby driving the brake pedal 3 to move according to the working conditions of the vehicle fuel consumption cycle test.

[0005] The above device can conveniently transplant the working conditions of the vehicle fuel consumption cycle test onto the engine test bench, making it easy to conduct 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.

[0006] Preferably, the test bench measurement and control system 11 can also receive data sent back by the pressure sensor 6, and use a proportional-integral-differential (PID) control method to drive the brake pedal 3 to move according to the working conditions of the vehicle fuel consumption cycle test.

[0007] This configuration uses closed-loop control, and with all sensors and servo systems responding sensitively, it can more accurately reproduce the operating conditions of the vehicle fuel consumption cycle test on the laboratory engine test bench.

[0008] Furthermore, the test bench measurement and control system 11 establishes a communication connection with the controller 8 and can directly read the data returned by the pressure sensor 6 from the controller 8 .

[0009] Preferably, the test bench measurement and control system 11 can control the brake pedal displacement actuator 10 to move at a uniform speed according to the working conditions of the fuel consumption cycle test.

[0010] This simplifies the working condition transplantation process, reduces possible faults and defects caused by too many components, and eliminates the fuel consumption deviation caused by the hysteresis in the closed-loop control that may cause the actual pressure curves of the brake chamber to not overlap in multiple tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 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;

[0012] 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;

[0013] 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;

[0014] Figure 4 1 is a schematic diagram corresponding to different control strategies of the electronically controlled air compressor in an embodiment of the present invention;

[0015] Figure 5 is a schematic diagram of the layout of the fuel-saving bench test device for the electronically controlled air compressor in an embodiment of the present invention,

[0016] Among them: 1. Electronically controlled air compressor; 2. Air storage tank; 3. Brake pedal; 4. Brake air chamber; 5. Pressure sensor; 6. Pressure sensor; 7. Relay; 8. Controller; 9. Vehicle battery; 10. Brake pedal displacement actuator; 11. Bench measurement and control system; 12. Motor forward and reverse controller; K1. Contact; K2. Contact. DETAILED DESCRIPTION

[0017] 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.

[0018] 1. Vehicle preparation before testing

[0019] The electrically connected vehicle battery 9, relay 7, controller 8, and the air tank 2, brake air chamber 4, brake pedal 3 and electronically controlled air compressor 1 connected through pipelines, the air tank 2 is installed with a pressure sensor 5, the brake air chamber 4 is installed with a pressure sensor 6, the controller 8 can receive the information sent back by the pressure sensor 5 and the pressure sensor 6 and control the start and stop of the electronically controlled air compressor 1 through the relay 7, and also includes a brake pedal displacement actuator 10 installed above the brake pedal 3, a bench measurement and control system 11, and a motor forward and reverse controller 12. The bench measurement and control system 11 can receive the vehicle fuel consumption cycle test data, and control the engine to operate according to the working conditions of the vehicle fuel consumption cycle test accordingly, and control the brake pedal displacement actuator 10 to move through the motor forward and reverse controller 12, thereby driving the brake pedal 3 to move according to the working conditions of the vehicle fuel consumption cycle test.

[0020] Replace the electronically controlled air compressor 1 on the vehicle, install the pressure sensor 6 on the brake air chamber 4 of the vehicle, and electrically connect the controller 8 with the electronically controlled air compressor 1, the pressure sensor 6, the relay 7 and the vehicle battery 9 to ensure that the controller 8 can normally control the operation of the electronically controlled air compressor 1 and read the value of the pressure sensor 6. The controller 8 drives the relay 7 to be normally closed, so that the electronically controlled air compressor is in the working mode of a conventional mechanical air compressor. Before the test, ensure that the brake system air tank 2 is full of air.

[0021] 2. Acquisition of basic data of vehicle fuel consumption cycle and recording of test parameters

[0022] 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.

[0023] Relay 7 is set to be normally closed to ensure that the electronically controlled air compressor is always in the pumping state 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.

[0024] 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 chamber pressure sensor; by monitoring the pressure value of the brake chamber pressure sensor, the driver's braking point, braking duration and brake chamber pressure (corresponding to the braking depth of the brake pedal) in the vehicle's C-WTVC condition can be known.

[0025] 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 brake chamber pressure sensor is superimposed on the speed 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.

[0026] Table 1: Engine speed, torque and brake chamber pressure

[0027]

[0028]

[0029] 3. Transplantation of working conditions from vehicle to test bench and preparation for fuel saving test of electronically controlled air compressor test bench

[0030] The basic data of the vehicle fuel consumption cycle test conditions obtained in the above steps and the information of braking time, braking duration and brake chamber pressure (corresponding to the braking depth of the brake pedal) are input into the engine test bench measurement and control system 11 as the basic data for the engine test bench to perform C-WTVC. The fuel saving efficiency comparison test of the electronically controlled air compressor under any different control strategies is carried out on this basic data.

[0031] Before conducting the C-WTVC test on the engine bench, the electronically controlled air compressor 1 is installed on the engine, and the components related to the vehicle braking system (air dryer assembly, four-protection valve, air tank 2, brake pedal 3, quick release valve assembly, front / rear axle assembly, etc.) and the pedal displacement actuator 10 (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 measurement and control system 11.

[0032] The air tank 2, brake air chamber 4, brake pedal 3 and electronically controlled air compressor 1 are connected through pipelines, a pressure sensor 5 is installed on the air tank 2, a pressure sensor 6 is installed on the brake air chamber 4, and the controller 8 is electrically connected to the electronically controlled air compressor 1, the pressure sensor 6, the relay 7 and the vehicle battery 9 to ensure that the controller 8 can control the operation of the electronically controlled air compressor 1 and read the value of the pressure sensor 6 according to the built-in control strategy program.

[0033] The test bench control system 11 can receive the basic data of the vehicle fuel consumption cycle test, establish a communication connection with the controller 8 and the motor forward and reverse controller 12, install the brake pedal displacement actuator 10 above the brake pedal 3, and connect the motor driven by the motor forward and reverse controller 12 through the pedal displacement actuator 10.

[0034] The engine test bench measurement and control system 11 adopts PID closed-loop control, and can operate the engine according to the working condition specifications imported in the aforementioned Table 1. The controller 8 receives the pressure value of the brake air chamber 4 fed back by the pressure sensor 6, and controls the brake pedal displacement actuator 10 to push the brake pedal 3 to move accordingly.

[0035] In order to avoid the deviation of the test condition due to the untimely response of the PID closed-loop control and the equipment accuracy error, the PID closed-loop control may not be used during the working condition transplantation. Instead, the response action of the brake pedal 3 may be regulated by controlling the pedal displacement actuator 10 to move at a uniform speed, as shown in Table 2.

[0036] The brake pedal displacement actuator 10 uses an electric push rod, which can convert the uniform rotational motion of the motor into the linear reciprocating uniform motion of the push rod through the worm gear transmission pair. The stroke and thrust-related parameters of the electric push rod need to be determined according to the stroke and thrust of the brake pedal. At the same time, the electric push rod needs to have a self-locking protection function for the stroke (that is, after reaching the maximum stroke, the stroke of the electric push rod will not change even when it is powered on, and the push rod will only move in the opposite direction when a reverse voltage is applied). The A / B port of the motor forward and reverse controller 12 is electrically connected to the brake pedal displacement actuator 10. When the A and B terminals output a positive voltage, the electric push rod extends to push the pedal. When the A and B terminals output a negative voltage, the electric push rod retracts the brake pedal to reset. The motor switching between the A and B terminals of the motor forward and reverse controller 12 is controlled by the closed state of the contact K1\contact K2. When the contact K1 is closed and the contact K2 is disconnected, the A and B terminals output a positive voltage. When the contact K2 is closed and the contact K1 is disconnected, the A and B terminals output a negative voltage. The opening and closing timing control of contact K1\contact K2 is controlled through the digital port of the test bench measurement and control system, where port D01 corresponds to contact K1, port D02 corresponds to contact K2, and the contact corresponding to the high voltage output of each port is closed.

[0037] As shown in the following table, the engine speed OBD_EngineSpeed ​​and torque value OBD_RealTorque of the C-WTVC working condition measured by the vehicle hub test are input into the measurement and control system of the engine bench, and the engine bench measurement and control system is required to control the operation of the engine according to the speed and torque values ​​per second in the following table; at the same time, the digital output ports D01 and D02 of the engine bench measurement and control system output control signals according to the high and low level timing per second in the following table to control the state of the relay contacts K1 and K2. The number 1 represents a high level, and the number 0 represents a low level. When the high level is high, the relay is energized, and when the low level is low, the relay is disconnected. When the D01 port is high and the D02 port is low, the contact K1 is energized and the contact K2 is disconnected, and the electronic push rod extends outward to push the brake pedal for braking; when the D02 port is low and the D02 port is high, the contact K2 is energized and the contact K1 is disconnected, and the electronic push rod is retracted to reset the brake pedal.

[0038] By converting the vehicle braking signal into high and low level timing signals of the digital port of the engine test bench measurement and control system, the linkage between the engine speed, torque signal and braking signal can be achieved.

[0039] Table 2: Signal linkage processing table of engine test bench measurement and control system

[0040]

[0041]

[0042] 4. Engine Bench C-WTVC Fuel Consumption Test

[0043] 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.

[0044] 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 state is consistent each time the engine undergoes the C-WTVC fuel consumption test; ensuring that the air tank 2 is full of gas during each test; checking the zero point and full point of the fuel consumption meter to ensure the consistency of the zero point and full point of the fuel consumption meter each time the engine undergoes the C-WTVC fuel consumption test.

[0045] 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.

[0046] The most basic fuel-saving control strategy of the electronically controlled air compressor 1 is to control the lower limit of the pressure of the air tank. When the pressure value of the air tank 2 is lower than the set value, the electronically controlled air compressor starts to run to replenish the air in the air tank 2 until it is full of air, and then the electronically controlled air compressor 1 stops working. However, in addition to this most basic fuel-saving control strategy, the electronically controlled air compressor 1 also has other fuel-saving control strategies, such as controlling the upper limit of the pressure of the air tank, or controlling the number of times the unloading pressure of the unloading valve of the brake system 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 3 below is a C-WTVC engine bench test fuel consumption record table for an electronically controlled air compressor under different control strategies. By comparing the fuel consumption of each strategy in the table with S1, the corresponding fuel saving rate of different control strategies can be obtained.

[0047] Table 3: Different control strategies for electronically controlled air compressors

[0048]

[0049] 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.

[0050] 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.

[0051] 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 including 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.

[0052] 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 in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0053] 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 bench test device for an electronically controlled air compressor, comprising an electrically connected vehicle battery (9), a relay (7), a controller (8), and an air tank (2), a brake air chamber (4), a brake pedal (3), and an electronically controlled air compressor (1) connected through a pipeline, wherein a pressure sensor (5) is installed on the air tank (2), and a pressure sensor (6) is installed on the brake air chamber (4). The controller (8) can receive information returned by the pressure sensor (5) and the pressure sensor (6) and control the start and stop of the electronically controlled air compressor (1) through the relay (7), characterized in that: It also includes a brake pedal displacement actuator (10) installed above the brake pedal (3), a bench measurement and control system (11), and a motor forward and reverse rotation controller (12); the bench measurement and control system (11) can receive vehicle fuel consumption cycle test data, and control the engine to operate according to the working conditions of the vehicle fuel consumption cycle test, and control the movement of the brake pedal displacement actuator (10) through the motor forward and reverse rotation controller (12), thereby driving the brake pedal (3) to move according to the working conditions of the vehicle fuel consumption cycle test; The test bench measurement and control system (11) can also receive data sent back by the pressure sensor (6) in the brake air chamber, and use a proportional-integral-differential (PID) control method to drive the brake pedal (3) to move according to the working conditions of the vehicle fuel consumption cycle test.

2. The fuel-saving bench test device for an electronically controlled air compressor according to claim 1, characterized in that The bench measurement and control system (11) establishes a communication connection with the controller (8) and can directly read the data sent back by the pressure sensor (6) from the controller (8).

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