CN111811821A

CN111811821A - Matching and calibration test method and system for three-cylinder engine of small racing car

Info

Publication number: CN111811821A
Application number: CN202010698565.7A
Authority: CN
Inventors: 石振; 王轲轲; 彭黎
Original assignee: Hubei University of Automotive Technology
Current assignee: Hubei University of Automotive Technology
Priority date: 2020-07-20
Filing date: 2020-07-20
Publication date: 2020-10-23

Abstract

The invention belongs to the technical field of racing car engine calibration, and discloses a matching and calibration test method and a system for a three-cylinder engine of a small racing car, which are used for completing model selection matching of an ECU (electronic control Unit) and a sensor; then processing and manufacturing a coupler and an engine bracket to complete the construction of the experiment bench; in the bench test process, basic parameter setting of the ECU and calibration work of various sensors are completed; comparing and analyzing the previous year competition data to finish the division of MAP graph load and engine speed gradient; the method comprises the following steps of carrying out detailed calibration on fuel injection and ignition Main MAP by taking the dynamic property and the fuel economy of an engine as targets; and corresponding improvement is made aiming at the sudden change working condition points on the MAP, so that the MAP is smoother, and the data of the engine rack is analyzed and evaluated. The invention completes the ECU parameter configuration and the engine sensor calibration work, realizes the matching design of the ECU and the engine and ensures the normal work of the engine.

Description

Matching and calibration test method and system for three-cylinder engine of small racing car

Technical Field

The invention belongs to the technical field of racing car engine calibration, and particularly relates to a matching and calibration test method and system for a three-cylinder engine of a small racing car.

Background

Currently, Formula SAE (FSAE) is a college project design competition created in 1978 by the society of International automotive Engineers (SAE International), which states that the team members must be the college students and require the college design team to design and manufacture a well-behaved small Formula race car within a year of time and complete all the competition items. The competition items comprise two aspects of a dynamic item which is completed by a player driving a racing car in person and a static item which is developed in an answer form, and the performance of the racing car is evaluated by scoring. Today, FSAE events are held in 15 different countries each year, for up to 20 yards and attracting the co-participation of hundreds of fleets from the top-level universities worldwide.

In terms of racing dynamics, naturally aspirated engines must incorporate a circular restriction valve with a diameter of no more than 20.0mm behind the throttle body. Due to the limitation of the competition rules, the air inlet characteristic of the engine is changed, so that the dynamic property of the engine is reduced, and the engine cannot work normally. For the reasons, calibration parameters stored in the ECU when the engine leaves the factory are no longer applicable, and in order to enable the engine to normally work and output greater power on the premise of limited air intake, it is necessary to perform a new matching design on an engine control system and perform a calibration test.

In 1978, when an FSAE event was first launched, the participating fleet was all using carburetors as fuel supply devices for the engines, subject to engine technology limitations. In 1997, with the continuous maturation of the technology of electronic fuel injection engines, the rules of the race were modified, allowing the use of electronic fuel injection engines to drive racing cars. At the moment, engine calibration work carried out by the ECU of the original factory is abandoned by each racing fleet and each college. Competition is becoming more intense with technological innovation, but it is readily apparent that in the last two years of competition, fleets of vehicles carrying out ECU replacement and engine calibration work have dominated the first ten major FSAE events. The first FSAE event is officially held in China in 2010, each large fleet is just formed, the preparation time is insufficient, most fleets also adopt original factory ECUs, and the problem that the air input of an engine is limited is solved by other methods, for example, an FSAE racing engine of a Ji-Ling university speed fleet is simultaneously provided with a turbocharging and mechanical supercharging double-supercharging system; however, the development of the engine calibration system of the domestic FSAE racing car is rapid, and in the second year after the competition is introduced into China, the participating racing car fleets of domestic famous colleges and universities such as Beijing Miller university, Harbin industry university (Weihai) and the like all adopt MoTeC series ECU and carry out the engine calibration work. Along with the lapse of time, each motorcade of participating in the race is constantly innovated in engine technical field, and former factory ECU has failed to satisfy the motorcade demand, and more motorcades of participating in the race begin to abandon former factory ECU. By the formula automobile competition of the ninth college students in China in 2018, the competition fleet with more than 9 years abandons the ECU of the original factory, and meanwhile, the calibration work of the engine is also deepened continuously.

Through the above analysis, the problems and defects of the prior art are as follows: in the aspect of the dynamic property of racing cars, the naturally aspirated engine is required to be additionally provided with a circular ring-shaped flow limiting valve with the diameter not more than 20.0mm behind a throttle body; due to the limitation of the competition rules, the air inlet characteristic of the engine is changed, so that the dynamic property of the engine is reduced, and the engine cannot work normally. Meanwhile, after an air inlet system of the engine is changed, the ECU of the original engine cannot accurately judge the working condition of the engine, so that the working state of the engine is deteriorated; because the ECU of the original engine cannot be directly written, the calibration data of the original engine is not suitable for a brand new air intake system any more. Therefore, the ECU with mature technology and open system is adopted to replace the original ECU, and a set of open engine control system is built again.

The difficulty in solving the above problems and defects is:

because a fully-substituted ECU is adopted, the calibration wiring harness needs to be redesigned and manufactured according to the ECU port schematic diagram and the UTC wiring harness connection schematic diagram, so that the communication between the ECU and the notebook computer is realized, and the data transmission and acquisition work of the sensor is completed; except for the engine crankshaft position sensor, other sensors are replaced by the same type of sensors with higher precision, so that the working characteristics of the sensors are not matched with the ECU (electronic control unit), namely the problem of sensor calibration is faced; the original engine ECU reading and writing authority of the engine is not opened, the working parameters of the engine cannot be directly changed, basic parameter setting work needs to be completed after the ECU is replaced, and the problem that the engine cannot be started or the idle speed is unstable after the engine is started is solved; the calibration data of the ECU of the original engine cannot be directly read, so that the basic MAP drawing problem is also faced. When the ignition Main MAP calibration is carried out, the problem that the rotating speed of a dynamometer is difficult to maintain due to the fact that the rotating speed of an engine is changed rapidly by changing the ignition advance angle blindly is faced.

The significance of solving the problems and the defects is as follows: because of the limitation of test equipment and environment, aiming at the test, the method has a plurality of defects, and a plurality of parts are worth extending and promoting: (1) the calibration of the engine under the three-high extreme environment is not carried out, the performance of the engine under the extreme environment is unknown, and the auxiliary correction of the extreme environment is set according to the empirical value and is not verified by the test. (2) The method is characterized in that the Main MAP and the Main MAP for ignition obtained by a calibration test are actually carried out in a standard laboratory environment, although auxiliary correction is carried out on partial environmental parameters, in the actual running process of an engine, the running condition of the engine changes instantly and extreme operations such as rapid acceleration and rapid deceleration are frequently carried out on racing cars, so that the final Main MAP and the Main MAP for ignition need to be adjusted in the actual driving process.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method and a system for testing matching and calibration of a three-cylinder engine of a small racing car.

The invention is realized in this way, a method for testing matching and calibration of a three-cylinder engine of a small racing car comprises the following steps:

firstly, completing the model selection matching of an ECU and sensors in the preparation work of the early stage of a bench test, and completing the manufacture of a calibration wire harness according to a MoTeCM800 port schematic diagram and a Daytona675 circuit diagram, so that the ECU and ECU Manager management software establish communication and can read data of various sensors;

secondly, processing and manufacturing a coupler and an engine bracket, mounting and fixing the engine on the test bed, and completing flexible connection between the engine and the dynamometer, so as to complete the construction of the test bed;

step three, in the bench test process, firstly, basic parameter setting of the ECU and calibration work of various sensors are completed, so that the ECU controls the engine and the idle speed of the engine is ensured to be stable;

step four, comparing and analyzing the previous year competition data to finish the division of MAP graph load and engine speed gradient;

step five, taking the dynamic property and the fuel economy of the engine as targets, carrying out detailed calibration on the injection and ignition Main MAP, and carrying out corresponding auxiliary correction on the temperature of the cooling liquid, the temperature of the intake air and the like;

and step six, after the bench test is completed, correspondingly improving the working condition points of sudden change on the MAP, enabling the MAP to be smoother, and analyzing and evaluating the bench data of the engine.

Further, in the step one, the ECU parameters are specifically set as follows:

setting main parameters, namely setting parameters to be set in a MoTeC ECU Manager management software main parameter setting interface, namely a cylinder number, an oil injection MAP efficiency calculation method and an ignition MAP load calculation method, namely a metering method of engine air flow;

setting ignition system parameters, setting basic parameters, wherein the parameters to be set in a basic parameter setting interface of the MoTeC ECU Manager ignition system comprise an ignition system trigger mode, the number of ignition coils, ignition delay time, an ignition advance angle correction mode, an ignition advance angle compensation mode and ignition system driving current;

setting parameters of an oil injection system, setting basic parameters, wherein the parameters needing to be set in an oil injection system basic parameter setting interface of MoTeC ECU Manager management software comprise maximum oil injection pulse width, oil injector driving current, peak voltage proportion, oil injection timing position and accelerated enrichment mode; and after the basic parameter setting of the oil injection system is finished, carrying out voltage compensation on the oil injector, and setting a voltage compensation table of the oil injector.

Further, after the basic parameter setting of the ignition system is finished, setting coil energy storage time; ignition sequence is set, the ignition output of the MoTeC M800ECU adopts a sequential mode, and an ECU port outputs ignition signals in sequence to control the corresponding igniter to work.

Further, the setting method of the number of the cylinders comprises the following steps: the number of cylinders of the four-stroke engine is represented by positive integers, the number of cylinders of the two-stroke engine is represented by negative integers, and the number of cylinders of the rotary engine is represented by negative integers;

the metering methods of the air flow of the engine are totally four in MoTeC M800: "1" represents a throttle-speed control method, "2" represents a speed-density control method, "3" represents a mass flow control method, and "4" represents a ratio of an intake manifold absolute pressure value to a value of the custom sensor "1".

Further, in the first step, the engine sensor matching process is as follows:

the crank shaft position sensor of the engine body is magnetoelectric, is mounted on the front end of the crank shaft, is provided with a 24-tooth fluted disc with 2 teeth uniformly distributed, inputs the signals to an ECU after shaping and amplifying pulse signals, and selects an 8-way spark mode;

during calibration of the throttle position sensor, only the initial value and the final value of the throttle position sensor are needed to be calibrated, the pressure sensor of the intake manifold is calibrated, a Delco 100kPa pressure sensor is selected as the pressure sensor of the intake manifold, and calibration data are already recorded in a sensor calibration database of ECU Manager management software;

the calibration of the intake air temperature sensor is carried out by taking 10 ℃ as a gradient value to calibrate the sensor in the calibration process; the temperature sensor of the cooling liquid is required to be completely immersed in kerosene at the head part of the thermometer and the detection part of the sensor in the calibration process and is not required to be in contact with the wall of the beaker.

Further, the calibration process of the throttle position sensor is as follows:

(1) selecting a 'Throttle Pos Closed' setting item in a calibration interface of the Throttle position sensor, adjusting the Throttle to a completely Closed state, knocking an 'enter' key on a keyboard after calibration data are stable, and determining an output value of the Throttle position sensor in the completely Closed state;

(2) selecting a 'Throttle Pos Open' setting item in a calibration interface of the Throttle position sensor, adjusting the Throttle to be in a fully Open state, knocking an 'enter' key on a keyboard after calibration data are stable, and determining an output value of the Throttle position sensor in full opening.

Further, the intake air temperature sensor calibration process is as follows:

(1) adding appropriate kerosene into a beaker, simultaneously placing a thermometer, completely immersing the head of the thermometer in the kerosene, and preparing an alcohol lamp for heating;

(2) the student power supply is used for adjusting the voltage to 5V to supply power for the intake air temperature sensor, the universal meter is adjusted to a voltage level, a red meter pen of the universal meter is connected with a signal line of the sensor, and a black meter pen of the universal meter is connected with a ground wire of the sensor;

(3) igniting an alcohol lamp to heat, slowly raising the temperature of kerosene in the beaker, and recording a temperature value and a corresponding multimeter voltage value once without 10 ℃ interval.

Further, in the second step, the process of matching the engine and the dynamometer is as follows:

the connection scheme of the engine and the dynamometer is that the transmission output shaft, the coupler, the flexible material, the adapter shaft and the dynamometer are adopted;

the engine bracket is smallest in size as far as possible on the premise of meeting the strength requirement, and the exhaust pipe is connected with the silencer through a spring.

Further, after the coupler and the output shaft of the transmission are connected in a spline fit mode, the engine is fixed on the test bed through the engine support;

measuring the circular runout of the coupler and the input shaft of the dynamometer by using a dial indicator, and continuously adjusting the position of the engine on a test bed to keep the runout within 1 mm;

the connection between the input shaft of the dynamometer and the coupler is completed by using the adapter shaft, and meanwhile, a flexible gasket is additionally arranged between the adapter shaft and the coupler, so that the flexible connection between the engine and the dynamometer is realized, and the vibration of a certain degree is relieved; and (5) matching design of an exhaust pipe.

Another object of the present invention is to provide a matching and calibration test system of a three-cylinder engine for a small racing car, which implements the matching and calibration test method of a three-cylinder engine for a small racing car, the matching and calibration test system of a three-cylinder engine for a small racing car is provided with an ECU engine control unit,

an ECU engine control unit is connected with a crankshaft position sensor, a camshaft position sensor, a throttle position sensor, an intake manifold pressure sensor, an intake temperature sensor, an oxygen sensor 1 and an oxygen sensor 2 through electric signals;

the ECU engine control unit is provided with AT input, thermal AV input and digital input, is respectively connected with an auxiliary sensor ground wire and an auxiliary sensor power line, and is connected with the ground wire which is connected with a 12V battery.

It is a further object of the invention to provide a computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of:

selecting and matching the ECU and the sensors, making a calibration wire harness, and reading data of various sensors;

manufacturing a coupler and an engine bracket, flexibly connecting an engine and a dynamometer, and building an experiment bench;

finishing basic parameter setting of the ECU and calibration of various sensors, so that the ECU controls the engine and the idle speed of the engine is stable;

dividing MAP graph load and engine speed gradient;

calibrating oil injection and ignition, and correcting the temperature of cooling liquid and the temperature of intake air;

and improving the working condition points of the sudden change on the MAP to smooth the MAP, and analyzing the data of the engine pedestal.

It is another object of the present invention to provide a computer-readable storage medium storing a computer program which, when executed by a processor, causes the processor to perform the steps of:

dividing MAP graph load and engine speed gradient;

By combining all the technical schemes, the invention has the advantages and positive effects that:

the invention analyzes the technical characteristics of the electric control gasoline engine used in the test and researches the basic mechanism and the control principle of the electric control gasoline engine. The MoTeC M800ECU port schematic diagram and the Daytona675 circuit diagram are analyzed in detail, the two circuit diagrams are compared carefully, the calibration wiring harness schematic diagram is drawn by software, and the calibration wiring harness is manufactured to complete the matching design of the engine circuit. And the ECU parameter configuration and the engine sensor calibration work are completed, and the matching design of the ECU and the engine is realized to ensure that the engine can work normally. And the coupler and the engine support are designed and processed, so that the engine is installed and fixed on the test bed, and the flexible connection between the engine and the dynamometer is completed. And finishing the arrangement of the exhaust pipeline and other peripheral equipment, and finally finishing the construction of the test bench. In the engine calibration test process, the system analyzes the metering method of the air flow of the engine and the MoTeC calibration method, compares and analyzes the previous year match data, completes the division of MAP graph load and engine speed gradient, and determines the test scheme of the calibration test according to the throttle opening value. And then, calibrating the basic injection pulse width and the basic ignition advance angle, wherein the calibration test is actually carried out in a standard environment and has difference with the actual running environment of the engine, so that auxiliary correction calibration is carried out on the injection Main MAP and the ignition Main MAP according to the temperature of cooling liquid, the temperature of air intake and the like in order to reduce the influence of the change of the environment on the actual running of the engine. After the bench test is completed, corresponding improvement is made aiming at the sudden change working condition points on the MAP, so that the MAP is smoother, and an oil injection Main MAP and an ignition Main MAP of the engine are obtained. And analyzing the external characteristic curve of the engine, and obtaining the improvement of the engine power after the engine is subjected to matching design and recalibration from the external characteristic curve of the engine. In the normal rotating speed interval 6000-9500r/min, the engine has power output of over 51 N.m, and when the rotating speed of the engine is 12000r/min, the power reaches the maximum and is 55.3 kw. Meanwhile, the calibration test adopts the throttle opening value to define the load of the working condition point of the engine, so that the engine torsion curve graph under different loads is drawn, the torque output of the engine continuously and stably increases along with the increase of the throttle opening, and the engine has good power performance under each throttle opening.

Technical effect or experimental effect of comparison.

The basic injection pulse width of the engine is the product of IJPU and the value in the MainMAP injection map. The values in the Main MAP for injection of Daytona675 engine were overall lower than for the CBR 600 engine for the same IJPU, from which it was concluded that Daytona675 engine fuel economy was significantly better.

After the engine is matched and designed and recalibrated, the engine power is improved. In the normal rotating speed interval 6000-9500r/min, the engine has power output of over 51 N.m, and when the rotating speed of the engine is 12000r/min, the power reaches the maximum and is 58.9 kw. The peak torque of the Daytona675 engine is improved by 12.19% compared with that of the CBR 600 engine; and in the low rotating speed interval 3000-. It can be seen from 38 that, since the throttle position sensor signal is used to define the load of the operating point of the engine during the calibration test, the torque output of the engine continuously and stably increases with the increase of the throttle opening, and the engine has good power performance under each throttle opening; meanwhile, within the conventional rotating speed range 6000-9500r/min, the engine torque output has high sensitivity relative to the throttle opening degree change. The engine has quick response to a certain extent, and is beneficial to the operation of a driver.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained from the drawings without creative efforts.

FIG. 1 is a flow chart of a method for testing matching and calibration of a three-cylinder engine of a small racing car according to an embodiment of the invention.

Fig. 2 is a basic configuration diagram of an Electronic Control Unit (ECU) provided by the embodiment of the present invention.

Fig. 3 is a structural diagram of an electronic control ignition system provided by the embodiment of the invention.

Fig. 4 is a block diagram of a piezo-resistive intake manifold pressure sensor according to an embodiment of the present invention.

Fig. 5 is a block diagram of a throttle position sensor provided in accordance with an embodiment of the present invention.

Fig. 6 is a structural diagram of a temperature sensor according to an embodiment of the present invention.

Fig. 7 is a structural diagram of an oxygen sensor according to an embodiment of the present invention.

Fig. 8 is a structural view of a crank position sensor provided in the embodiment of the present invention.

FIG. 9 is a schematic diagram of a hydraulic dynamometer provided by an embodiment of the invention.

Fig. 10 is a schematic diagram of an eddy current dynamometer provided in an embodiment of the present invention.

Fig. 11 is a schematic diagram of a dynamometer of the electric dynamometer provided by the embodiment of the invention.

FIG. 12 is a diagram of a MoTeC M800ECU in accordance with an embodiment of the present invention.

Fig. 13 is a schematic view of a MoTeC M800 port provided in an embodiment of the present invention.

FIG. 14 is a diagram of a MoTeC UTC object provided by an embodiment of the present invention.

Fig. 15 is a schematic diagram of UTC harness connection provided in an embodiment of the present invention.

FIG. 16 is a schematic diagram of a main interface of MoTeC ECU Manager management software according to an embodiment of the present invention.

FIG. 17 is a schematic view of an ECU Manager management software toolbar according to an embodiment of the present invention.

FIG. 18 is a schematic diagram of the ECU Manager management software status bar provided by the embodiment of the present invention.

FIG. 19 is a schematic diagram of an ECU Manager management software working interface provided by an embodiment of the present invention.

FIG. 20 is a schematic diagram of an ECU Manager management software sensor setup interface provided by an embodiment of the present invention.

FIG. 21 is a schematic view of an ECU Manager management software interface provided by an embodiment of the present invention.

Fig. 22 is a schematic diagram of a wiring harness provided by an embodiment of the present invention.

FIG. 23 is an intake manifold pressure sensor calibration provided by an embodiment of the present invention.

FIG. 24 is a calibration graph of an intake air temperature sensor provided in accordance with an embodiment of the present invention.

FIG. 25 is a calibration graph of a coolant temperature sensor according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides a method and a system for matching and calibrating a three-cylinder engine of a small racing car, and the invention is described in detail below with reference to the attached drawings.

As shown in fig. 1, a method for testing matching and calibration of a three-cylinder engine of a small racing car according to an embodiment of the present invention includes:

s101: in the preparation work of the bench test at the early stage, the type selection matching of the ECU and the sensors is completed, and the manufacturing of the calibration wiring harness is completed according to the MoTeCM800 port schematic diagram and the Daytona675 circuit diagram, so that the ECU and the ECU Manager management software establish communication and can read data of various sensors.

S102: and then, the shaft coupling and the engine support are processed and manufactured, the installation and the fixation of the engine on the test bed are realized, and the flexible connection between the engine and the dynamometer is completed, so that the construction of the test bed is completed.

S103: in the bench test process, basic parameter setting of the ECU and calibration work of various sensors are firstly completed, so that the ECU controls the engine and the idle speed of the engine is ensured to be stable.

S104: and comparing and analyzing the previous year competition data to finish the division of the MAP graph load and the engine speed gradient.

S105: the method is characterized in that the dynamic property and the fuel economy of an engine are taken as targets, the injection and ignition Main MAP is calibrated in detail, and corresponding auxiliary correction is carried out according to the temperature of cooling liquid, the temperature of intake air and the like.

S106: after the bench test is completed, corresponding improvement is made aiming at the sudden change working condition point on the MAP, so that the MAP is smoother, and the data of the engine bench is analyzed and evaluated.

In S101, the ECU parameter setting provided by the embodiment of the present invention is specifically as follows:

1. setting main parameters, namely setting parameters to be set in a MoTeC ECU Manager management software main parameter setting interface, namely a cylinder number, an oil injection MAP efficiency calculation method and an ignition MAP load calculation method, namely a metering method of engine air flow;

the setting method of the number of the cylinders comprises the following steps: the number of cylinders of the four-stroke engine is represented by positive integers, the number of cylinders of the two-stroke engine is represented by negative integers, and the number of cylinders of the rotary engine is represented by negative integers;

2. Ignition system parameter setting

Setting basic parameters, wherein the parameters to be set in a basic parameter setting interface of the MoTeC ECU Manager management software ignition system comprise an ignition system trigger mode, the number of ignition coils, ignition delay time, an ignition advance angle correction mode, an ignition advance angle compensation mode, ignition system driving current and the like. After the basic parameters of the ignition system are set, setting coil energy storage time; ignition sequence is set, the ignition output of the MoTeC M800ECU adopts a sequential mode, and an ECU port outputs ignition signals in sequence to control the corresponding igniter to work.

3. Fuel injection system parameter settings

Setting basic parameters, wherein the parameters to be set in a basic parameter setting interface of the MoTeC ECU Manager management software fuel injection system comprise maximum fuel injection pulse width, fuel injector driving current, peak voltage proportion, fuel injection timing position, acceleration enrichment mode and the like. And after the basic parameter setting of the oil injection system is finished, carrying out voltage compensation on the oil injector, and setting a voltage compensation table of the oil injector.

The engine sensor matching process in S101 provided by the embodiment of the invention is as follows:

the crank shaft position sensor of the engine body is magnetoelectric, is mounted on the front end of the crank shaft, is provided with a 24-tooth fluted disc with 2 teeth uniformly distributed, inputs the signals to an ECU after shaping and amplifying pulse signals, and selects an 8-way spark mode; the calibration of the throttle position sensor only needs to calibrate the initial value and the final value of the throttle position sensor in the calibration process. And (3) calibrating the intake manifold pressure sensor, namely selecting a Delco 100kPa pressure sensor as the intake manifold pressure sensor, and recording calibration data in a sensor calibration database of ECU Manager management software. The intake air temperature sensor is calibrated by taking 10 ℃ as a gradient value in the calibration process. The temperature sensor of the cooling liquid is required to be completely immersed in kerosene at the head part of the thermometer and the detection part of the sensor in the calibration process and is not required to be in contact with the wall of the beaker.

The calibration process of the throttle position sensor comprises the following steps:

(1) selecting a 'Throttle Pos Closed' setting item in a calibration interface of the Throttle position sensor, adjusting the Throttle to a fully Closed state, knocking an 'enter' key on a keyboard after calibration data are stable, and determining an output value of the Throttle position sensor in the fully Closed state.

The calibration process of the air inlet temperature sensor comprises the following steps:

(1) the appropriate kerosene was added to the beaker while the thermometer was placed and the thermometer head was completely immersed in the kerosene and prepared for heating by an alcohol lamp.

(2) The student power supply is used for adjusting the voltage to 5V to supply power for the air inlet temperature sensor, the universal meter is adjusted to a voltage level, a red meter pen of the universal meter is connected with a signal line of the sensor, and a black meter pen is connected with a ground wire of the sensor.

In S102 provided by the implementation of the present invention, the process of matching the engine and the dynamometer is as follows:

the engine bracket is minimized in size as far as possible on the premise of meeting the strength requirement, and after the coupler and the output shaft of the transmission are connected in a spline fit mode, the engine is fixed on the test bed by the engine bracket; the circular runout of the coupler and the dynamometer input shaft is measured by using the dial indicator, the position of the engine on the test bed is continuously adjusted, the runout is kept within 1mm, finally, the dynamometer input shaft is connected with the coupler by using the transfer shaft, meanwhile, a flexible gasket is additionally arranged between the transfer shaft and the coupler, the flexible connection of the engine and the dynamometer is realized, and the vibration of a certain degree is relieved.

The exhaust pipe is matched with the silencer and is connected with the silencer through a spring.

The matching and calibration test system of the three-cylinder engine of the small racing car provided by the embodiment of the invention is provided with an ECU engine control unit,

the ECU engine control unit sends electric signals to a crankshaft position sensor, a camshaft position sensor, a throttle position sensor, an intake manifold pressure sensor, an intake air temperature sensor, an oxygen sensor 1 and an oxygen sensor 2.

The technical solution of the present invention is further described with reference to the following examples.

Brief introduction to testing of electronically controlled gasoline engines

2.1 basic composition of electric control system of gasoline engine

1. Electronic Control Unit (ECU)

An Electronic Control Unit (ECU) is an electronic control device having comprehensiveness. The ECU is connected with the storage battery, the sensor and the actuator by utilizing the main plug to complete the work of signal acquisition, instruction sending and the like. A block diagram of the system is shown in fig. 2.

The ECU is used for receiving signals of the sensors, outputting obtained results in a command form after processing and calculation, and controlling the relevant actuators to act, so that the purpose of automatically controlling the engine is achieved.

2. Sensor with a sensor element

The sensor mainly plays a role in information perception and conversion, can perceive the measured change and convert the perceived change into an electric signal or a signal in other required forms according to a certain rule to be output, and therefore information transmission is completed. As can be seen from fig. 2, the digital signal is a pulse signal, and needs to be amplified and shaped before being input to the ECU. The analog signal is usually represented by a continuously varying voltage signal, and the analog signal needs to be converted into a digital signal by an a/D converter before being input to the ECU.

3. Actuator

An actuator is a mechanical mechanism or device. The actuator is strictly in accordance with

The control command output by the ECU completes specific operation actions, and the electric signal output by the ECU is converted into mechanical work, so that the engine is ensured to work in a set state.

2.2 electric control gasoline engine management system

2.2.1 basic constitution and control principle of electric control gasoline injection system

1. Air supply system

The air supply system is used for supplying air amount suitable for the engine according to the load of the engine when the engine runs and measuring air quality in a direct or indirect mode to provide basis for fuel injection amount. Air is filtered by an air filter, passes through a throttle valve control assembly, is measured by a sensor to be distributed to an intake manifold by an intake pipeline, is mixed with gasoline sprayed by a fuel injector at the tail end of the intake manifold to form combustible mixed gas, and is finally sucked into a cylinder to participate in combustion.

2. Gasoline supply system

The gasoline supply system is used for supplying gasoline required by the engine according to different operation conditions of the engine during the operation of the engine, and simultaneously finishing the filtering and atomizing work of the gasoline to ensure that the gasoline is better combusted. The gasoline pump extrudes the gasoline from the oil tank at a certain pressure, the pressure sensor senses the pressure value and the pressure value is received by the ECU, the extruded gasoline is filtered by the filter and then is conveyed to the oil injector through oil transportation, the oil injector sprays the gasoline according to an oil injection pulse signal sent by the ECU and atomizes the gasoline, and the oil injection quantity is determined by the gasoline pressure and the oil injection pulse signal together.

3. Electronic control unit

The Electronic Control Unit (ECU) mainly has the functions of signal acquisition and processing and instruction sending. The ECU receives the signals and then calculates and processes the signals to obtain the information of air inflow, rotating speed, temperature, air-fuel ratio and the like of the engine under the current working condition, determines the optimal oil injection quantity and the optimal oil injection time of the engine under the working condition according to programs and data stored in the ECU, and sends instructions to the oil injector to control the action of the oil injector to realize the optimal oil injection control.

2.2.2 basic constitution and control principle of electric control ignition system

The structure of the electronic ignition system is shown in fig. 3. The power supply provides the ignition system with the required ignition energy and is composed of a storage battery and a generator. In an electronic control ignition system, a sensor is mainly used for detecting the running state of an engine and providing basis for an ECU to control the ignition advance angle. When the electronic control ignition system works, the sensor continuously transmits the sensed change to the ECU, the ECU obtains information such as the rotating speed, load, coolant temperature and the like of the engine under the working condition after processing and calculation, determines the optimal ignition advance angle and the power-on time of the engine under the working condition according to programs and data stored in the ECU, and transmits an ignition instruction to the ignition control module. The ignition control module controls the ignition coil to act according to the ignition instruction of the ECU, so that the corresponding spark plug jumps to work and ignites the combustible mixture in the cylinder.

2.3Daytona 675 Engine technical characteristics

2.3.1Daytona 675 Engine basic parameters

In this test, a Daytona675 engine was selected as the subject, with a displacement of 674.8cc, and the other parameters of this engine are shown in Table 2.1.

TABLE 2.1 Daytona675 Engine base parameters

2.3.2Daytona 675 Engine Primary sensor

1. Intake manifold pressure sensor

An intake manifold pressure sensor is mounted on the intake manifold for detecting the intake pressure to estimate the intake air amount of the engine. The pressure sensor of the intake manifold is a piezoresistor type, when the pressure in the intake manifold changes, the piezoresistor deforms, the resistance value changes, and the output voltage correspondingly changes, so that the purpose of measuring the gas pressure in the intake manifold is achieved. The intake manifold pressure sensor is structured as shown in fig. 4.

2. Throttle position sensor

The throttle position sensor is arranged on the throttle body, and transmits throttle opening signals, acceleration and deceleration signals and the like to the ECU, so that the ECU can optimally control the oil injection quantity and the oil injection time according to the current operating condition of the engine. The structure and principle of the throttle position sensor is similar to a sliding resistor sheet, as shown in fig. 5. The rotation of the throttle valve rotating shaft drives the sliding contact to slide on the sliding sheet resistor, the resistance values of the sliding contact and the output signal end of the sensor change, and the output voltage signal and the throttle valve opening degree are in a direct proportion relation, so that the purpose of measuring the throttle valve opening degree is achieved.

3. Temperature sensor

The temperature sensor mainly comprises a coolant temperature sensor and an air inlet temperature sensor which are respectively arranged on the coolant pipeline and the air inlet pipeline and used for sensing the coolant temperature and the air inlet temperature in the running process of the engine, judging the thermal state of the engine under the working condition and calculating the air inlet flow. The temperature sensor adopts a negative temperature coefficient thermistor type, when the temperature changes, the resistance value of the thermistor also changes, and the output voltage also correspondingly changes, thereby achieving the purpose of detecting the temperature. The negative temperature coefficient means that the resistance value of the sensor decreases along with the rise of the temperature, the resistance of the sensor and the temperature value have a one-to-one correspondence relationship, the sensor is connected in series with a fixed value of resistance, and the corresponding temperature value can be calculated by detecting the voltage value obtained by dividing the resistance of the sensor. The structure is shown in fig. 6.

4. Oxygen sensor

The oxygen sensor is arranged on an engine exhaust pipeline, senses the actual air-fuel ratio in the running process of the engine in real time, provides a feedback signal of the air-fuel ratio to the ECU, and the ECU controls the fuel injection quantity according to a program and data stored in the ECU so that the actual air-fuel ratio is converged in a narrow range near a theoretical value, thereby reducing the generation of harmful substances in exhaust gas and reducing exhaust pollution. The oxygen sensor is of a zirconia type, and the basic element is a zirconia ceramic body. The structure is shown in fig. 7. When the zirconia ceramic body is heated to a higher temperature, oxygen molecules permeating into the zirconia ceramic body are ionized, and because the concentration of oxygen ions in the inner side of the zirconia ceramic body is higher than that in the outer side, the oxygen ions are diffused outwards, so that electromotive force is generated between the two electrodes, and because the magnitude of the electromotive force and the concentration of the oxygen in the waste gas have a one-to-one correspondence relationship, the magnitude of the electromotive force is detected, and then an oxygen concentration signal in the waste gas can be obtained.

5. Crankshaft position sensor

The crank position sensor is one of the most important sensors in the engine, provides an engine crank angle signal, a piston stroke position signal, an engine speed signal and the like for the ECU, and the ECU determines the basic oil injection quantity, the basic ignition advance angle, the oil injection time, the ignition time and the like of the engine according to the signals to ensure the normal operation of the engine. The crank position sensor is of a magnetoelectric type and has a structure shown in fig. 8. It is mainly composed of gear type signal disk, magnetic head, electromagnetic coil and related circuit. The crankshaft position sensor is provided with a gear type signal disc which is arranged at the front end and the rear end of the engine crankshaft. When the engine runs, the signal panel is driven to synchronously rotate along with the crankshaft, the magnetic flux in the electromagnetic coil periodically changes to generate an alternating induced electromotive force signal, and the signal is processed and then output to the ECU.

Chapter iii experimental equipment brief introduction

3.1 brief introduction to Experimental dynamometer

3.1.1 Classification and principle of dynamometer

1. Principle of hydraulic dynamometer

The rotor assembly on the main shaft of the dynamometer is mechanically connected with the engine through a coupler, the rotor assembly is driven to synchronously rotate when the engine runs, and the rotor assembly is located in the dynamometer to stir water in the working cavity. The centrifugal force generated by the rotation of the rotor and the action of the rotor pits promote water to generate strong water eddy between the dynamometer shell and the rotor pits, so that a rotating torque is applied to the dynamometer shell, the torque of the engine is transmitted to the dynamometer shell by the rotor, the dynamometer shell rotates by a certain angle, and a brake arm, namely a tension sensor, is mounted on the dynamometer shell. When the dynamometer shell is stressed to rotate by a certain angle, the brake arm transmits force to the tension sensor mechanically connected with the dynamometer shell, and the tension sensor senses the force and converts the force into an electric signal to be output, so that the aim of measuring the torque of the engine is fulfilled. The principle diagram of the hydraulic dynamometer is shown in FIG. 9.

2. Principle of electric eddy current dynamometer

The working principle of the electric eddy current dynamometer is the magnetic effect of current. When the dynamometer works, direct current is conducted to the excitation winding, and a magnetic field is generated around the excitation winding due to the fact that the current obtains a magnetic effect. The induction body is mechanically connected with the engine through a coupler, when the engine runs, the induction body is driven by the engine to rotate, eddy current is generated due to the periodic change of a magnetic density value, a magnetic field generated by the eddy current interacts with a magnetic field generating the eddy current, so that braking torque opposite to the running direction of the engine is generated, the braking torque acts on the armature body, the dynamometer armature body transmits braking force to the sensor through a force arm arranged on the dynamometer armature body, and the braking force is output after signal conversion, so that the aim of measuring the torque of the engine is fulfilled. The schematic diagram of the electric eddy current dynamometer is shown in fig. 10.

3. Dynamometer principle of electric dynamometer

The electric dynamometer is essentially a dc motor. The engine is mechanically connected with the direct current motor rotor through the coupler, and when the dynamometer works, the direct current motor stator and the direct current motor rotor simultaneously bear the torque generated by the motor. The stator is arranged on an independent bearing seat and can freely swing in a small range. The dynamometer shell is provided with a force measuring arm, and when the dynamometer shell is stressed and swings, the force measuring arm transmits the force applied to the dynamometer shell to the tension sensor, so that the aim of detecting the torque applied to the stator is fulfilled. According to the principle of the direct current motor, the following steps are known: the torque exerted by the motor on the stator and the rotor is equal in magnitude and opposite in direction, so that the torque output by the motor is the torque measured on the stator. Fig. 11 shows a schematic diagram of the dynamometer of the electric dynamometer.

3.1.2 calibration test instrument

The calibration test is completed by means of gasoline engine performance laboratory calibration test equipment of Hubei automobile industry academy, and an ET2000 eddy current measurement and control instrument is selected as test instrument equipment. The performance parameters of the ET2000 eddy current dynamometer are shown in table 3.1.

TABLE 3.1 ET2000 electric eddy current measuring and controlling instrument performance parameters

The list of the instruments and equipment used in the calibration test is shown in table 3.2. The engine measurement and control system is used for measuring the power and the torque of the engine; the accelerator actuator plays a role in changing the opening of a throttle valve in the calibration process, so that the load of an engine in the calibration process is changed; the spray fan is matched with the engine coolant constant temperature system for use, so that the temperature of the engine coolant is controlled in the calibration process, and the damage of the engine caused by overheating is prevented; the starting test power supply supplies power to the engine starting motor. The electronic fuel injection engine oil return processor is matched with the intelligent oil consumption meter for use, so that the oil consumption of the engine is measured.

TABLE 3.2 test Instrument Equipment List

3.2 Experimental ECU introduction

3.2.1MoTeC M800 ECU

MoTeC M800 is a compact professional-level engine control unit introduced by MoTeC in 2000. A real map of the MoTeC M800ECU is shown in FIG. 12. The ECU supports the control of 12-cylinder engines at most and supports the control of electronic throttle bodies. In the aspect of data storage and transmission, the MoTeC M800 is provided with a 1Mb data memory, one path of CAN communication and one path of RS232 serial port communication. Meanwhile, the signal input and output ports of the MoTeC M800 are also extremely rich, and part of the signal input and output ports support user-defined. Available for user-customized ports include: 4 analog temperature signal input ends, 6 analog voltage signal input ends and 8 auxiliary output ends. In addition, the signal input port includes: crankshaft position signal input, camshaft position signal input, throttle position signal input, intake manifold pressure signal input, machine oil pressure signal input, fuel pressure signal input, coolant temperature signal input, temperature signal input that admits air, exhaust temperature signal input, oxygen sensor signal input, 4 way digital input signal input that are used for the fast collection of wheel. The signal output port includes: 8 way oil spout output, 6 way ignition coil outputs. The port schematic is shown in fig. 13:

in addition, the MoTeC M800 also has many features and advanced functions, including: quick Lambda, starting control, traction control, turbocharging control, gear shifting and fire breaking and the like. The Quick Lambda is the most distinctive function of the MoTeC M800ECU, and the addition of the function simplifies the engine calibration test process and greatly improves the efficiency of the engine calibration test. In the calibration test process, a user only needs to press a 'Q' key on a keyboard, the ECU can receive data transmitted by the wide-area oxygen sensor in real time, compares the data with a target Lambda MAP preset by the user, and automatically adjusts the value in an oil injection pulse width MAP node to enable the value of the excess air coefficient of the current working point to be converged to a set value, so that a new oil injection pulse width MAP is generated.

MoTec M800 utilizes a CAN bus technology and an RS232 protocol to complete communication with other equipment, is provided with matched MoTeC ECU Manager management software, and facilitates a user to complete work such as parameter configuration and data modification inside an ECU. M800 communicates with the notebook computer by adopting a CAN bus technology, is connected with a USB interface of a computer end by using a MoTeC UTC and debugs a MoTeC ECU Manager. The connection mode of the UTC object and the wire harness is shown in FIGS. 14 and 15.

3.2.2MoTeC ECU Manager management software

The MoTeC ECU Manager is debugging software developed by matching with the MoTeC M800ECU, has a good human-computer interaction interface, supports user self-definition of interface layout and content, and can realize multi-page quick switching so as to adapt to debugging of engines and other equipment in different scenes. The main interface of which is shown in figure 16.

The upper left corner of the main interface is a toolbar of ECU Manager management software for shortcut operation of some common functions. The method mainly comprises data writing, data storage, remark editing, sensor monitoring, error codes, oil injection pulse width setting, ignition advance angle setting, target Lambda setting, main parameter setting, throttle position sensor calibration, sensor input setting and the like, and a user can conveniently and rapidly switch and set in the calibration test process. As shown in fig. 17.

The lower left corner of the main interface is a status bar of the ECU Manager management software for displaying the current connection status and the number of error codes of the ECU, as shown in fig. 18.

After the MoTeC UTC is used for establishing communication between the M800ECU and the notebook computer, a plurality of monitoring interfaces with different functions, including engine rotating speed, intake manifold pressure, intake air temperature, coolant temperature, air-fuel ratio difference, storage battery voltage, oil injection pulse width and the like, can be displayed in a working interface of ECU Manager management software, and the requirement of a user for monitoring data of each sensor and the running condition of the engine in real time in a calibration test process is met. The layout of the working interface, the display mode of the sensor data and the like can be customized by a user, and a plurality of working interfaces capable of being switched quickly can be set so as to meet the debugging of the engine in different scenes. The working interface is shown in fig. 19.

In order to complete the matching design of the engine and the ECU and enable the ECU to accurately control the operation of the engine, all sensors connected to the ECU are required to be set so as to ensure that all sensors of the engine can normally work in the calibration test process. The setting interface of the sensor in the ECUManager management software is shown in FIG. 20.

TABLE 3.3 ECU Manager management software sensor set-up interface

The view interface can display sensor data, ECU errors, knock information, GPS information, engine operation condition points and the like, can quickly enter the view interface by pressing V on a keyboard, and is convenient for a user to monitor the sensor information and the engine operation condition points, so that the current operation state of the engine can be quickly and accurately judged, and meanwhile, the view interface can also display the reason of abnormal operation of the engine, and is convenient for the user to carry out troubleshooting and processing. The view interface is shown in fig. 21.

TABLE 3.4 ECU Manager management software View interface

Matching design of chapter iv engine

4.1 matching design of ECU and Engine

4.1.1 Engine Circuit matching design

The original machine wiring harness is designed to be relatively integrated in consideration of tidiness and attractiveness, comprises an engine electrical system, an instrument and other electrical systems, is wired along an original machine frame, is fixed in length, and meanwhile, an A, B connector used by the original machine wiring harness is not matched with an interface of a MoTeC M800 ECU. And comprehensively considering, determining to abandon the original machine wire harness, and redesigning and manufacturing the wire harness used for the calibration test.

TABLE 4.1ECU and sensor and executor connection table

The wiring harness design and manufacture follows the principle of simplicity and reliability, and has logicality. In order to ensure the tidiness of the wiring harness, the sensor, the fuel injector and the ignition module share one bottom line. In order to ensure the reliability and safety of the calibration test wire harness, the working current is calculated according to the power of different electric equipment during the design of the wire harness, and the used line type is determined according to the magnitude of the current. When designing the wiring harness, firstly, a table shown in table 4.1 is drawn by combining the ECU port schematic diagram provided by the MoTeC official shown in fig. 9, and matching of the sensor and the MoTeC M800ECU input port and the actuator and the MoTeC M800ECU output port is completed. And then drawing a wiring harness schematic diagram by using drawing software, and adding a starting circuit, an emergency stop circuit, an oil supply circuit, a data acquisition circuit and the like. And finally, manufacturing a calibration test wire harness according to the wire harness schematic diagram. In the process of manufacturing the wire harness, in order to improve the shock resistance, friction resistance, high temperature resistance and waterproofness of the wire harness, special tool equipment is necessary to be used, such as: a wire harness connector, a waterproof connector, a double-wall heat-shrinkable tube, a hot air gun, wire stripper, wire crimper and the like. The specification and the color of the cable are marked, so that later-stage inspection is facilitated. Meanwhile, relevant control circuits such as: the starting circuit, the emergency stop circuit and the like need to be extended to a control room, so that the operation safety is improved. The wiring harness schematic is shown in fig. 22.

4.1.2ECU parameter settings

1. Main parameter setting

Parameters to be set in a main parameter setting interface of MoTeC ECU Manager management software include the number of cylinders, an oil injection MAP efficiency calculation method and an ignition MAP load calculation method, namely an engine air flow metering method. The setting method of the number of the cylinders comprises the following steps: the number of cylinders of a four-stroke engine is represented by a positive integer, the number of cylinders of a two-stroke engine is represented by a negative integer, and the number of cylinders of a rotary engine is represented by a negative integer. The metering methods of the air flow of the engine are totally four in MoTeC M800: "1" represents a throttle-speed control method, "2" represents a speed-density control method, "3" represents a mass flow control method, and "4" represents a ratio of an intake manifold absolute pressure value to a value of the custom sensor "1". Combining the practical condition of Daytona675 engine used in the test and the technical characteristic of high response speed of the required throttle, the number of cylinders is set to be 3, and the metering method of the air flow of the engine selects a throttle-speed control method and is set to be 1. The main parameter settings are shown in table 4.2.

TABLE 4.2 Main parameter settings

2. Ignition system parameter setting

(1) Basic parameter setting

The parameters required to be set in the basic parameter setting interface of the MoTeC ECU Manager management software ignition system include an ignition system trigger mode, the number of ignition coils, ignition delay time, an ignition advance angle correction mode, an ignition advance angle compensation mode, ignition system driving current and the like.

The ignition system triggering mode is an option for setting a triggering edge of an ignition system, wherein '1' represents falling edge triggering, and '2' represents rising edge triggering, and the parameter setting of 100 or more directly corresponds to a special ignition mode of some classical vehicle type engines, so that the traditional vehicle type engines can be directly matched conveniently, such as Mazda rotor engines and the like. By consulting the Daytona675 engine technical manual, the ignition system trigger type is set to "1", i.e., falling edge trigger; the number of the ignition coils is set according to the number of the physical coils, and the Daytona675 engine adopts an independent ignition mode, so that the number of the ignition coils is the same as that of the cylinders and is set to be 3; the ignition delay time is a time interval between the ECU issuing the ignition command and the ignition system performing the ignition operation, and may be set to "50" by default. The ignition advance angle correction mode comprises two modes: "0" represents a correction of the spark advance angle based on percentage, and "1" represents a correction of the spark advance angle based on angle. Since the engine spark advance is usually expressed by the angle of rotation of the crankshaft, mode "1" is selected, i.e., the spark advance is corrected based on the angle; the ignition advance angle compensation mode is a compensation setting of the ECU to the dynamic working condition of the engine, and comprises the following steps: the '0' represents that the ignition advance angle is reduced under the acceleration working condition, the ignition advance angle is increased under the deceleration working condition, the '1' is just opposite, the ignition advance angle is increased under the acceleration working condition, and the ignition advance angle is reduced under the deceleration working condition. Set to "0" here; the ignition system drive current has two types: "0" represents a low current mode and "1" represents a high current mode. The Daytona675 engine ignition system drives current in the high current mode, and is set to "1", i.e., the high current mode. Ignition system parameter settings are shown in table 4.3.

TABLE 4.3 ignition System parameter settings

(2) Coil energy storage time

After the basic parameter setting of the ignition system is completed, an extremely important parameter needs to be set, namely the energy storage time of the ignition coil. Under the influence of the voltage fluctuation of the battery, the energy stored by the ignition coil in the same energy storage time may be different, so that the discharge energy of the spark plug is influenced, and the combustion process in the cylinder is influenced finally. To avoid this phenomenon, the energy storage time of the ignition coil needs to be compensated for the battery voltage. The cell voltage compensation table is shown in table 4.4.

TABLE 4.4 Battery Voltage Compensation Table

(3) Ignition sequence arrangement

The ignition output of the MoTeC M800ECU adopts a sequential mode, and an ECU port outputs ignition signals in sequence to control the corresponding igniter to work. Referring to the Daytona675 engine technical manual, the cylinder ignition sequence is 1-2-3, so that the setting can be carried out according to the signal output sequence of the ECU. The firing sequence settings are shown in table 4.5.

TABLE 4.5 ignition sequence settings

3. Fuel injection system parameter settings

(1) Basic parameter setting

The parameters to be set in the basic parameter setting interface of the MoTeC ECU Manager management software fuel injection system include maximum fuel injection pulse width, fuel injector driving current, peak voltage proportion, fuel injection timing position, acceleration enrichment mode and the like.

The maximum injection pulse width (IJPU) refers to the longest duration of one time of opening of the injector, and is expressed in ms. The product of the IJPU and the value in the MAP of the oil injection is the basic oil injection pulse width. Here set to "4". The driving current of the oil injector refers to the current required for driving the oil injector to work, and is related to the resistance value of the oil injector. The recommended values provided in connection with the MoTeC and the injector are set to "0". The peak voltage ratio is set to the recommended value, set to "4". The fuel injection timing position determines the position of the fuel injector for injecting fuel, and comprises the following steps: "0" represents the end of injection and "1" represents the start of injection. Set to "0" here. The acceleration enrichment mode includes two types: "0" represents increased fuel injection during acceleration conditions and "1" represents decreased fuel injection during acceleration conditions. Set to "0" here. Fuel injection system parameter settings are shown in Table 4.6

TABLE 4.6 oil injection system parameter settings

(2) Injector voltage compensation

Similar to the setting of an ignition system, after the basic parameters of the fuel injection system are set, in order to reduce the fuel injection quantity error of the fuel injector caused by the voltage fluctuation of the battery, a voltage compensation table of the fuel injector is required to be set. The cell voltage compensation table is shown in table 4.7.

TABLE 4.7 Battery Voltage Compensation Table

4.1.3 Engine sensor matching

1. Crankshaft position sensor

A crankshaft position sensor arranged on an engine body is magnetoelectric, is arranged at the front end of a crankshaft and is provided with a fluted disc with 24 uniformly distributed teeth and 2 teeth, and pulse signals are input into an ECU after being shaped and amplified, so that the rotating speed and the crankshaft position of the engine are accurately measured. The method is limited by the structural design of the engine, the engine is not provided with a camshaft position sensor, and the selection between two control modes is finally determined by combining the technical characteristics of the MoTeC M800ECU, wherein the two control modes are respectively as follows: "65" Kawasaki mode, "8" wait spark mode.

Looking up the MoTeC M800ECU User Manual, the Kawasaki mode requires that the crankshaft fluted disc of the engine is of a missing 2 tooth type, a camshaft position sensor is not needed, and an intake manifold pressure sensor is used for replacing the camshaft position to provide a cylinder top dead center signal for the ECU. Compared with the technical characteristics of the Daytona675 engine, the Daytona675 engine can meet the use premise of the Kawasaki mode, and only one pressure sensor needs to be additionally arranged on a cylinder intake manifold if the Kawasaki mode is used. In the actual operation process, when the MoTeC M800ECU is used for controlling the engine, if the original air inlet system is installed, the engine is started normally and runs stably. However, when the modified intake system is installed and the test conditions are the same, the engine cannot be started. After careful comparison, the air inlet manifold of the original air inlet system of the engine is directly communicated with the atmosphere, and the pressure value in the air inlet manifold changes obviously in the running process of the engine. The reformed air inlet system meets the competition rule, and a pressure stabilizing cavity is additionally arranged on the structure for improving the air charging quantity, so that the pressure change of an air inlet manifold is not obvious, the ECU can not identify the pressure value change of the air inlet manifold, and an accurate ignition signal can not be sent, thereby causing the engine to not run normally. So the wait spark mode is decided to be used.

In the wait spark mode, the trigger mode selects "8", and the spark plug discharges twice during one cycle of the cylinder, once in the power stroke and once in the exhaust stroke. The number of teeth of the coding disc is equal to the number of teeth of uniformly distributed teeth of a fluted disc of the crankshaft, and the coding disc comprises the number of missing teeth, wherein the number of teeth is set to be 24; the gear ratio is set to determine the threshold value for judging the gear missing, and the proper gear ratio setting can enable the ECU to judge the gear missing position more accurately, so that a trigger signal is provided. Typically set to a default value of "50"; the crankshaft index tooth position (CRIP) refers to the angle the crankshaft rotates from the index position in the crankshaft fluted disc to the top dead center of the compression stroke, and can be measured by an ignition timing gun. However, since the wait spark mode is adopted, the ECU cannot determine whether the piston is at the compression stroke top dead center or the exhaust stroke top dead center. The actual angle of the engine crankshaft rotation is set to 315 CA as measured when the piston first reaches top dead center after the crankshaft has rotated past the index position. Set to "315";

two types of crankshaft position sensors are provided in an ECU for selection by a user, wherein the two types of crankshaft position sensors are respectively as follows: "1" represents a Hall sensor, "2" represents a magnetoelectric sensor, and the Daytona675 engine adopts a magnetoelectric sensor, so is set to "2"; the trigger edge setting represents the trigger mode of the crankshaft signal, wherein '0' represents a falling edge, and '1' represents a rising edge, and the trigger edge setting is set to '1' because signals are acquired by an oscilloscope and analyzed to obtain the rising edge. The crankshaft position sensor parameter settings are shown in table 4.8.

TABLE 4.8 crankshaft position sensor parameter settings

2. Throttle position sensor calibration

The Daytona675 engine adopts a throttle position sensor as a potentiometer, the structural principle is similar to that of a sliding resistance card, and the signal output of the sensor is linear output. Therefore, only the initial value and the final value of the calibration process need to be calibrated. Usually, due to manufacturing or assembly errors, the throttle position sensor has dead zones at both ends of its stroke, within which the sensor output signal deviates significantly from the actual situation, and therefore needs to be avoided during calibration. If the position of the throttle valve is changed or the position of the throttle valve position sensor is changed, the throttle valve position sensor needs to be calibrated again so as to ensure the normal operation of the engine.

The specific calibration process is as follows:

(2) Selecting a 'Throttle Pos Open' setting item in a calibration interface of the Throttle position sensor, adjusting the Throttle to be in a fully Open state, knocking an 'enter' key on a keyboard after calibration data are stable, and determining an output value of the Throttle position sensor in full opening. The throttle position sensor calibration data is shown in table 4.9.

TABLE 4.9 throttle position sensor calibration

3. Intake manifold pressure sensor calibration

The intake manifold pressure sensor adopts a piezoresistor type, is connected with the intake manifold by using a hose, and is prevented from being directly installed on an engine body during installation, so that inaccurate sensor reading is prevented from being caused by interference of shaking of the engine on an output signal of the sensor. After comprehensive comparison and analysis, a common Delco 100kPa pressure sensor is determined to be selected as the intake manifold pressure sensor, and due to the universality and universality of the sensor, calibration data of the sensor is recorded in a sensor calibration database of ECU Manager management software, so that the sensor can be directly called. The calibration data is shown in FIG. 23.

4. Intake temperature sensor calibration

The air inlet temperature sensor adopts a negative temperature coefficient thermistor type, and the resistance value of the thermistor and the temperature have a one-to-one correspondence relationship. However, as the function relation of the resistance value of the thermistor along with the temperature change is nonlinear, the sensor is calibrated by taking 10 ℃ as a gradient value in the calibration process.

The specific calibration process is as follows:

The calibration results are shown in fig. 24.

5. Coolant temperature sensor calibration

The principle and the calibration process of the engine coolant temperature sensor are the same as those of an air inlet temperature sensor, a negative temperature coefficient thermistor type is also adopted, and the aim of measuring the temperature of the engine coolant is achieved by utilizing the one-to-one correspondence relationship between the resistance value of the thermistor and the temperature. However, as the function relation of the resistance value of the thermistor along with the temperature change is nonlinear, the sensor is calibrated by taking 10 ℃ as a gradient value in the calibration process. The calibration process is the same as that of the near-air temperature sensor, and the head of the thermometer and the detection part of the sensor need to be completely immersed in kerosene in the calibration process and cannot be in contact with the wall of the beaker. The calibration results are shown in fig. 25.

4.2 matching design of engine and dynamometer

4.2.1 coupling matching design

The Daytona675 engine is an engine used on a motorcycle manufactured and sold by Kesoon, UK, and unlike an automobile engine, its transmission is in a single housing with the engine.

In addition, the motorcycle adopts chain transmission, and the output shaft of the transmission is also special. The coupling connecting the engine and the dynamometer also has a large difference in structure from most engines. The output shaft structure of the Daytona675 engine transmission is an involute spline. Considering the structural characteristics of the output shaft of the transmission, the connection scheme of the engine and the dynamometer is finally determined to be the transmission output shaft, the coupler, the flexible material, the coupling shaft and the dynamometer.

4.2.2 Engine Mount design

The engine bracket plays a role in supporting the engine and buffering the vibration of the engine in the calibration test process. In order to ensure the coaxiality of the output shaft of the speed changer and the input shaft of the dynamometer and facilitate the centering of the engine, the engine is positioned by adopting an engine bracket which is designed and processed by self. The strength and the size of the bracket are comprehensively considered in the design process, if the strength of the bracket is not enough, the bracket may deform in the process of high-speed and high-load operation of the engine, so that the relative position of the engine and the dynamometer is changed, and the engine shakes. Also, considering that the space for disposing the bracket is limited, the bracket having an excessively large size may interfere with the engine body or the exhaust system. Therefore, in the design process, the size should be minimized as much as possible while meeting the strength requirement.

After the coupler and the output shaft of the transmission are connected in a matched mode through the spline, the engine is fixed on the test bed through the engine support. The circular runout of the coupler and the dynamometer input shaft is measured by using the dial indicator, the position of the engine on the test bed is continuously adjusted, the runout is kept within 1mm, finally, the dynamometer input shaft is connected with the coupler by using the adapter shaft, meanwhile, the flexible gasket is additionally arranged between the adapter shaft and the coupler, the flexible connection of the engine and the dynamometer is realized, and the vibration of a certain degree is relieved.

4.2.3 exhaust pipe matching design

The original exhaust pipe of the Daytona675 engine penetrates through the bottom of the engine for a second time, and interferes with an engine support in the process of erecting a rack, so that the exhaust pipe needs to be designed and matched again to solve the interference problem. After comprehensive consideration and analysis, the exhaust pipe is determined to penetrate through the side of the engine and a three-in-one arrangement mode is adopted. The exhaust pipe is connected with the silencer through a spring to reduce vibration. Meanwhile, the temperature of the exhaust pipe is extremely high in consideration of the fact that the engine runs under a large-load working condition for a long time in the calibration test process. Therefore, an engine oil supply system and a wire harness are required to be disclosed in the exhaust pipe arrangement process.

5. The invention is further described below in connection with engine calibration tests.

5.1 Engine calibration test method

5.1.1 Engine air flow metering method

In general, the ECU adjusts the fuel injection quantity according to the air intake quantity under the current working condition of the engine so as to realize the control of the air-fuel ratio. Therefore, the accuracy of measuring the air flow rate largely determines the accuracy of controlling the air-fuel ratio.

1. Speed-density control method

The ECU collects pressure signals of an air inlet manifold and rotating speed signals of the engine to measure air inflow of each working cycle of the engine, and then calculates the required fuel quantity under the working condition to control the fuel injector to inject fuel. Because the intake air flow under different working conditions has larger difference to cause fluctuation of the intake pressure value, the accuracy of the intake air amount measured by the speed-density control method is not high, but the charging efficiency is high and the use cost is low.

2. Mass flow control method

The mass flow control method senses the air inflow of the engine by using an air flow meter, converts the air inflow into an electric signal and transmits the electric signal to the ECU. And determining the oil supply quantity required by the engine running under the working condition by combining the engine speed signal acquired by the ECU, and controlling the oil injector to inject the fuel oil. Compared with a speed-density control method and a throttle-speed control method, the method has high measurement precision and good stability.

3. Throttle valve speed control method

The throttle-speed method measures the amount of intake air per one operating cycle of the engine based on the throttle opening and the engine speed. And (5) after the fuel supply quantity under the working condition is calculated, controlling the fuel injector to inject fuel. The mechanism is simple and the manufacturing cost is low.

The engine electric control system has the advantages of high control precision and quick response, and can optimally control the oil injection parameters and the ignition parameters according to the operating condition of the engine. Meanwhile, the engine electric control system has a fault diagnosis function, so that the reliability of the engine is further improved. Considering that the engine is often under the working conditions of rapid acceleration and rapid deceleration in the actual operation process, in order to ensure the quick response of an engine electric control system, a throttle opening signal is adopted to define the load of an engine working condition point, namely, a throttle-speed control method is adopted to meter the air flow of the engine.

5.1.2MoTeC calibration method

In order to ensure that the power output of the engine is smoother in the whole operation interval, the operation is smoother. Theoretically, the finer the division of the operating point, the smaller the span of each operating point is, the better. However, the division of the operating points in the actual operation process cannot be infinite, and too many operating points are too dense, which brings inconvenience to the later-stage engine debugging. The accurate control of the ECU on the engine by using a limited number of operating points is very important, and in this respect, the MoTeC M800ECU is realized by using a linear interpolation method between two operating points.

During bench test, the dynamometer is adjusted to a constant rotating speed mode, the dynamometer provides reverse torque to stabilize the rotating speed of the engine within a certain range, the throttle is adjusted from an idle position to a full open state, the load of the engine is continuously increased, meanwhile, oil injection MAP and ignition MAP are calibrated, and the counter torque which is applied to the engine by the dynamometer and used for maintaining the rotating speed of the engine is the torque of the engine under the working condition.

5.2 Engine pedestal calibration test

5.2.1 basic injection pulsewidth calibration

The fuel injection pulse width is a parameter for measuring fuel injection quantity by the ECU and consists of a basic fuel injection pulse width and an auxiliary correction quantity. When the ECU measures the injected quantity, the basic injection pulsewidth is the basic value, so it is calibrated first. In the MoTeCM800 ECU, the basic injection pulsewidth is determined by the Main MAP injection, and when the Main MAP injection calibration is performed, the auxiliary injection pulsewidth correction is closed completely. And starting the engine to maintain the idling working condition and fully warm up the engine until the water temperature reaches 85-90 ℃, and maintaining the water temperature of the engine to be constant in the whole calibration test process.

The dynamometer is adjusted to a constant rotation mode, and the throttle valve opening degree is changed by adjusting the throttle valve actuator under the condition of maintaining the constant rotating speed of the engine, so that the load is changed when the engine operates. After the engine stably works at an expected working condition point, the Lambda value is adjusted through the Quick Lambda function speed to be converged near a target value, the obtained oil injection pulse width value is basic oil injection pulse width data of the working condition point, and the torque output value of the engine at the working condition point is recorded. According to the method, calibration of all load points of the throttle valve from an idle state to a full-open state at a certain rotating speed is completed. And changing the rotating speed of the dynamometer, and by analogy, completing the calibration of the engine load points in all rotating speed intervals.

5.2.2 basic spark advance calibration

The influence of the ignition advance angle of the engine on the engine is mainly reflected on the dynamic property and the fuel economy of the engine. The ignition advance angle is too small, and the gasoline is combusted in the process of increasing the volume of the cylinder, so that the combustion heat efficiency of the engine is reduced, and the dynamic property is reduced; the ignition advance angle is too large, the gasoline is ignited to do work when the piston is still in an ascending stage, the ascending of the piston is blocked, the efficiency is reduced, and the engine can knock in serious conditions, so that the abrasion of the engine is aggravated, and even the irreversibility damage is caused to the engine body. The basic ignition advance angle calibration refers to the ignition advance angle which can enable the engine to output the maximum torque and has no occurrence of explosion through tests under the condition that the engine normally works. It has been found through experimentation that engine torque output increases with increasing spark advance angle before the engine spark advance angle value has been adjusted to the optimum spark advance value. In the MoTeCM800 ECU, a basic ignition advance angle is determined by ignition Main MAP, and when the ignition Main MAP is calibrated, in order to avoid the sudden change of the engine speed caused by the blind increase or decrease of the ignition advance angle, the global modification function and the parameter value fine adjustment function of the MoTeC M800ECU are determined. The global modification function operates in the following manner: after the MoTeC M800ECU Manager management software ignites the Main MAP to select a certain working condition point, a 'Shift' key of a keyboard is pressed, all the required working condition points are selected by using a direction key, and parameters are input by using a numeric keyboard. At this time, all the parameters of the selected operating points are modified. The operation mode of the parameter value fine-tuning function is as follows: selecting a certain working condition point, using the keys of 'Page Up' and 'Page Down' to finely adjust the selected parameter value by taking 0.5 DEG CA as gradient, adjusting to a proper value, and pressing the key of 'Enter' for confirmation.

The calibration of the ignition Main MAP should be synchronized with the calibration of the injection Main MAP. Before the ignition Main MAP calibration is carried out, all the ignition advance auxiliary correction quantity is turned off firstly. And starting the engine to maintain the idling working condition and fully warm up the engine until the water temperature reaches 85-90 ℃, and maintaining the water temperature of the engine to be constant in the whole calibration test process. And (3) adjusting the dynamometer to a constant rotation mode, firstly, integrally adjusting the parameter values in the ignition Main MAP down by 1 CA by using the global modification function, calibrating the fuel injection pulse width, observing the torque output change of the engine, and determining whether the ignition advance angle has an adjustable space. And if the torque of the engine is found to be reduced after the operation is finished, calibrating the ignition advance angle by using a parameter value fine adjustment function. The method comprises the steps of maintaining the operation condition of an engine to a calibration working condition point, calibrating the oil injection pulse width by utilizing a Quick Lambda function, switching to an ignition Main MAP interface to press a 'Page Up' key, increasing the ignition advance angle by 0.5 DEG CA, observing torque output of the engine after the engine operates stably, repeating the steps if the torque is increased, pressing an 'Enter' to confirm a calibration value until the engine torque is not increased any more, wherein the ignition advance angle parameter value at the moment is the best ignition advance angle parameter value under the current operation working condition. After calibration of all working condition points of the throttle valve from an idle state to a full-open state at a certain rotating speed is completed, the rotating speed of the dynamometer is changed, and calibration of the working condition points of the engine in all rotating speed intervals is completed by the same method.

5.3 environmental parameter assisted correction

In order to ensure the operating conditions of the engine to be consistent and eliminate the influence of the environmental parameters on the calibration test, the environmental parameters are basically maintained unchanged in the calibration test process, such as: ensure that the laboratory temperature is maintained at 20 ℃ and the like. Meanwhile, when calibration of injection and ignition Main MAP is carried out, auxiliary correction quantity is completely closed through MoTeC M800ECU Manager management software, the engine is fully warmed up before the test is carried out, and the water temperature is kept constant in the test process.

However, in the actual operation process of the engine, the environmental parameters are not controlled by human beings any more and cannot be kept consistent completely, for example, the intake temperature of the engine is changed due to the difference of the environmental temperature in different seasons; at different altitudes, the lean degree of air may have an effect on the intake air amount of the engine. The values of the parameters in the injection and ignition Main MAP are determined and not changed, and the control of the engine cannot be adjusted according to the change of the environmental parameters. In order to eliminate the influence of the environmental parameters and ensure that the engine can still maintain good performance in various complex and variable environments, the environmental parameters need to be corrected in an auxiliary manner. In the auxiliary correction test process of the environmental parameters, a single variable principle is adopted, namely, only one parameter is changed while other environmental parameters are kept unchanged in the test process, and the running state of the engine is kept consistent with the reference state or the difference between the running state and the reference state is reduced as much as possible by calibrating the parameter values of the corresponding auxiliary correction table.

5.3.1 intake air temperature assisted correction

Along with the rise of the air inlet temperature, the air charging coefficient of the engine is reduced, meanwhile, the high temperature is also beneficial to the propagation of flame, the combustion speed of the mixed gas is high, the knocking tendency is increased, and therefore, the ignition advance angle is properly reduced; as the temperature of the intake air decreases, the combustion condition of the air-fuel mixture deteriorates and ignition becomes difficult, and in order to improve the combustion condition, the air-fuel mixture should be further compressed, that is, the ignition advance angle should be appropriately reduced. The amount of correction of the ignition timing based on the intake air temperature is shown in table 5.1.

TABLE 5.1 spark advance-intake air temperature correction

5.3.2 Coolant temperature assisted correction

The temperature of the wall surface of the air inlet channel is mainly influenced by the temperature of the engine, when the temperature of the engine is low during cold start or warm-up, the temperature of the wall surface of the air inlet channel is low, the evaporation speed of gasoline is low, and then an adherent oil film cannot be well mixed with air due to poor gasification, so that the mixed gas is too dilute. Additional fuel injection is required. When the temperature of the engine is too high, the fuel injection quantity is properly increased in order to improve the temperature condition of the engine. The correction amount of the fuel injection amount based on the coolant temperature is shown in table 5.2.

TABLE 5.2 correction of spray-coolant temperature

5.4 data analysis

The basic injection pulse width of the engine is the product of IJPU and the value in the MAP of the injection MAP. The values in the Main MAP for injection of Daytona675 engine were overall lower than for the CBR 600 engine for the same IJPU, from which it was concluded that Daytona675 engine fuel economy was significantly better.

And finally obtaining the engine external characteristic curve by calibrating the basic oil injection pulse width, the basic ignition advance angle and the environmental parameters.

After the engine is matched and designed and recalibrated, the engine power is improved. In the normal rotating speed interval 6000-9500r/min, the engine has power output of over 51 N.m, and when the rotating speed of the engine is 12000r/min, the power reaches the maximum and is 58.9 kw. The peak torque of the Daytona675 engine is improved by 12.19% compared with that of the CBR 600 engine; and in the low rotating speed interval 3000-. Combining with competition data, the engine is in a low-rotation-speed interval in an 8-shaped encircling competition project, and meanwhile, torque improvement in the middle-low-rotation-speed interval is obviously more favorable for improving the power performance of the track with good working conditions, which is more beneficial to the multi-low-speed curve of the Xiangyang dream racing track, so that the requirement of the competition can be met, and the aim of improving the power performance is fulfilled.

It can be seen that, because the throttle position sensor signal is adopted to define the load of the engine operating point in the calibration test process, the torque output of the engine continuously and stably increases along with the increase of the throttle opening, and the engine has good power performance under each throttle opening; meanwhile, within the conventional rotating speed range 6000-9500r/min, the engine torque output has high sensitivity relative to the throttle opening degree change. The engine has quick response to a certain extent, which is beneficial to the operation of a driver; when the opening of the throttle valve is between 90% and 100%, the torque output curves of the engine are almost completely overlapped, which shows that the performance of the engine is limited due to the limitation of a 20mm throttle valve in the Gauss rule, and when the opening of the throttle valve reaches over 90%, the torque output of the engine does not have too large lifting space, and even has the phenomenon of reduction at partial rotating speed points.

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for testing matching and calibration of a three-cylinder engine of a small racing car is characterized by comprising the following steps:

firstly, selecting and matching types of an ECU and sensors, manufacturing a calibration wire harness, and reading data of various sensors;

manufacturing a coupler and an engine support, flexibly connecting an engine and a dynamometer, and building an experiment bench;

step three, completing basic parameter setting of the ECU and calibration of various sensors, so that the ECU controls the engine and the idle speed of the engine is stable;

step four, dividing MAP graph load and engine speed gradient;

step five, calibrating oil injection and ignition, and correcting the temperature of the cooling liquid and the temperature of the intake air;

and step six, improving the sudden change working condition points on the MAP to smooth the MAP, and analyzing the data of the engine pedestal.

2. The method for testing matching and calibration of a three-cylinder engine of a small racing car as claimed in claim 1, wherein in the step one, the ECU parameter setting specifically comprises:

setting main parameters, namely setting the number of cylinders, fuel injection MAP efficiency calculation and ignition MAP load calculation parameters and metering parameters of the air flow of the engine;

setting ignition system parameters, namely setting an ignition system trigger mode, the number of ignition coils, ignition delay time, an ignition advance angle correction mode, an ignition advance angle compensation mode and ignition system drive current parameters;

setting parameters of an oil injection system, namely setting parameters of a maximum oil injection pulse width, an oil injector driving current, a peak voltage proportion, an oil injection timing position and an accelerated enrichment mode; and after the basic parameters are set, performing voltage compensation on the oil sprayer, and setting a voltage compensation table of the oil sprayer.

3. The method for matching and calibrating a three-cylinder engine of a small racing car as claimed in claim 2, wherein after the basic parameter setting of the ignition system is completed, the coil energy storage time is set; the ignition sequence is set, the ignition output of the ECU adopts a sequential mode, and the ECU port outputs ignition signals in sequence to control the corresponding igniter to work.

4. A method for testing the matching and calibration of a three-cylinder engine of a slot car as claimed in claim 2, wherein the setting of the number of cylinders comprises: the number of cylinders of the four-stroke engine is represented by positive integers, the number of cylinders of the two-stroke engine is represented by negative integers, and the number of cylinders is represented by negative integers for a rotary engine;

the setting of the engine air flow rate comprises: 1 represents throttle-speed control, 2 represents speed-density control, 3 represents mass flow control, and 4 represents the ratio of intake manifold absolute pressure value to the value of custom sensor 1.

5. The method for matching and calibrating a three-cylinder engine of a small racing car as claimed in claim 1, wherein in the step one, the engine sensor matching process comprises:

the crank shaft position sensor of the engine body is in a magnetoelectric type, is arranged at the front end of the crank shaft, is provided with a 24-tooth fluted disc with uniformly distributed 2 teeth, and inputs pulse signals into an ECU after shaping and amplifying the pulse signals;

the calibration of the throttle position sensor only calibrates the initial value and the final value in the calibration process, the intake manifold pressure sensor calibrates, the pressure sensor is selected as the intake manifold pressure sensor, and the calibration data is recorded in a sensor calibration database of ECU management software;

the calibration of the intake air temperature sensor is carried out by taking 10 ℃ as a gradient value to calibrate the sensor in the calibration process; the temperature sensor of the cooling liquid is completely immersed in kerosene at the head of the thermometer and the detection part of the sensor in the calibration process.

6. The method for matching and calibrating a three-cylinder engine for a slot car according to claim 5, wherein the throttle position sensor calibration process comprises:

(1) setting in a calibration interface of a throttle position sensor, adjusting the throttle to a fully closed state, and determining an output value of the throttle position sensor in the fully closed state after calibration data are stable;

(2) and setting in a calibration interface of the throttle position sensor, adjusting the throttle to be in a fully open state, and determining the output value of the throttle position sensor in the fully open state after the calibration data is stable.

7. The method for matching and calibrating a three-cylinder engine of a small racing car as claimed in claim 1, wherein in the second step, the process of matching the engine with the dynamometer comprises the following steps:

the engine and the dynamometer are connected by a transmission output shaft, a coupling, a flexible material, a transfer shaft and the dynamometer;

after the coupler is matched and connected with the output shaft of the transmission through a spline, the engine is fixed on the test bed by using the engine bracket;

measuring the circular runout of the coupler and the input shaft of the dynamometer by using a dial indicator, and continuously adjusting the position of the engine on the test bed;

the connecting shaft is utilized to complete the connection of the input shaft of the dynamometer and the coupler, and meanwhile, a flexible gasket is additionally arranged between the connecting shaft and the coupler, so that the flexible connection of the engine and the dynamometer is realized.

8. A match and calibration test system for a three-cylinder engine of a slot car implementing the match and calibration test method for a three-cylinder engine of a slot car according to claims 1-7, wherein the match and calibration test system for a three-cylinder engine of a slot car is provided with an ECU engine control unit;

9. A computer device, characterized in that the computer device comprises a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to carry out the steps of:

dividing MAP graph load and engine speed gradient;

10. A computer-readable storage medium storing a computer program which, when executed by a processor, causes the processor to perform the steps of:

dividing MAP graph load and engine speed gradient;