阅读说明：本技术 用于测定汽油辛烷值、柴油十六烷值的装置及方法 (Device and method for determining gasoline octane number and diesel cetane number ) 是由 曾学军 韩庆民 颜文 刘冬峰 于 2021-08-12 设计创作，主要内容包括：本发明提供了一种用于测定汽油辛烷值、柴油十六烷值的装置及方法,包括可变压缩比发动机,所述可变压缩比发动机内设置有用于检测缸压的第一传感器和用于检测可变压缩比发动机运行相位的第二传感器；进气模块,所述进气模块通过进气道与可变压缩比发动机连通；喷油模块,所述喷油模块与进气模块和可变压缩比发动机之间的进气道连通。将多组已知辛烷值或十六烷值的标准燃料在可压缩比发动机内燃烧并得到特征压缩比与标准燃料辛烷值或十六烷值的对应关系,使待测燃料在相同的条件下燃烧测得特征压缩比,测试待测燃料的辛烷值或十六烷值,实现了只使用一台机械测试汽油辛烷值和柴油十六烷值,减少了检测仪器的占地面积,且降低了投资。(The invention provides a device and a method for measuring gasoline octane number and diesel cetane number, comprising a variable compression ratio engine, wherein a first sensor for detecting cylinder pressure and a second sensor for detecting the running phase of the variable compression ratio engine are arranged in the variable compression ratio engine; an intake module in communication with a variable compression ratio engine through an intake passage; and the oil injection module is communicated with an air inlet channel between the air inlet module and the variable compression ratio engine. The method has the advantages that multiple groups of standard fuels with known octane numbers or cetane numbers are combusted in the compressibility ratio engine, the corresponding relation between the characteristic compression ratio and the octane number or the cetane number of the standard fuels is obtained, the fuel to be tested is combusted under the same condition to measure the characteristic compression ratio, the octane number or the cetane number of the fuel to be tested is tested, the purpose of testing the octane number and the cetane number of the gasoline and the diesel by using one machine is achieved, the occupied area of a detection instrument is reduced, and the investment is reduced.)

1. The device for measuring the octane number of gasoline and the cetane number of diesel oil is characterized by comprising a variable compression ratio engine (1), wherein a first sensor for detecting cylinder pressure and a second sensor for detecting the running phase of the variable compression ratio engine (1) are arranged in the variable compression ratio engine (1);

the air inlet module (2), the air inlet module (2) is communicated with the variable compression ratio engine (1) through an air inlet channel;

the fuel injection module (3) is communicated with an air inlet channel between the air inlet module (2) and the variable compression ratio engine (1);

the auxiliary function module (4), the said auxiliary function module (4) is used for exhausting the heat dissipation, filtering and silencing;

the operation control module (5), operation control module (5) are used for carrying out operation, demonstration and observing and controlling to the device.

2. The device for determining the octane number of gasoline and the cetane number of diesel according to claim 1, wherein the intake module (2) comprises a natural intake unit (7), a supercharged intake unit (8) and an intake air conditioning unit (9), and the intake air conditioning unit (9) filters, dehumidifies and controls the temperature of the gas entering the variable compression ratio engine (1).

3. The device for determining the octane number of gasoline and the cetane number of diesel oil according to claim 1, wherein the fuel injection module (3) comprises a fuel storage tank set (11), the fuel storage tank set (11) comprises a standard fuel oil storage tank, a fuel oil storage tank to be tested and a heat engine fuel oil storage tank, the oil outlets of the standard fuel oil storage tank, the fuel oil storage tank to be tested and the heat engine fuel oil storage tank are connected with a selective valve (13), and the selective valve (13) is communicated with the fuel injection nozzle (15).

4. A method for determining the octane number of gasoline, characterized in that it comprises an apparatus for determining the octane number of gasoline, the cetane number of diesel according to claims 1-3, said method comprising the steps of:

s1, selecting the controllable air inlet module (2) as natural air inlet, setting the temperature, pressure and humidity of air inlet, setting the temperature of air mixture and setting the ignition advance angle of the variable compression ratio engine (1);

s2, assembling a group of standard fuel with known octane number, fuel to be tested and heat engine fuel in an oil storage tank in the oil injection module (3);

s3, selecting heat engine fuel, and starting and preheating the variable compression ratio engine (1);

s4, selecting a standard fuel with a known octane number to be sprayed into an air inlet channel, premixing the standard fuel with air, then entering the variable compression ratio engine (1), igniting the premix of the standard fuel with the known octane number and the air to generate detonation, adjusting the fuel injection quantity, and measuring the maximum detonation intensity of the fuel injection quantity through a first sensor;

s5, adjusting the engine compression ratio of the variable compression ratio engine to enable the maximum knock intensity to be a fixed value, and obtaining the corresponding relation between the characteristic compression ratio and the standard fuel octane number;

s6, selecting different types of standard fuels, repeating the step S4 and the step S5 to obtain the corresponding relation between the characteristic compression ratio and the fuel octane number of the different types of standard fuels under the same combustion condition, and establishing an octane number-characteristic compression ratio curve through mathematical fitting;

s7, selecting the fuel to be tested, repeating the steps S4 and S5 under the same working condition to obtain the characteristic compression ratio of the fuel to be tested, and obtaining the octane number of the fuel to be tested by utilizing the octane number-characteristic compression ratio curve.

5. The method for measuring the octane number of gasoline according to claim 4, wherein the octane number of gasoline includes motor octane number and research octane number, and for the step S1, when the octane number of gasoline is measured, the inlet temperature of the controllable inlet module (2) is 155 + -10 ℃, the inlet pressure is normal pressure, the inlet humidity is 3.56-7.12 water/kg dry air, and the set temperature of the mixed gas is 155 + -10 ℃;

when the research octane number is measured, the air inlet temperature of the controllable air inlet module (2) is 52 +/-1 ℃, the air inlet pressure is normal pressure, the air inlet humidity is 3.56-7.12 water/kg dry air, and the set temperature of the mixed air is 52 +/-1 ℃.

6. The method for determining the octane number of gasoline according to claim 5, characterized in that the variable compression ratio engine (1) is rotated at 900 ± 9r/min when determining the octane number of motor;

the rotational speed of the variable compression ratio engine (1) is 600 +/-6 r/min when the research octane number is measured.

7. Method for determining the octane number of gasoline according to claim 4, characterized in that for step S1, the spark advance angle of the variable compression ratio engine (1) is 13 °.

8. A method for determining the cetane number of diesel oil, comprising an apparatus for determining the octane number of gasoline and the cetane number of diesel oil according to claims 1 to 3, said method comprising the steps of:

s1, selecting the controllable air inlet module (2) as supercharged air inlet, and setting air inlet temperature, air inlet pressure and air mixture temperature;

s2, a group of standard fuel with known cetane number, fuel to be tested and heat engine fuel are filled in an oil storage tank group (11) in the oil injection module (3);

s3, selecting heat engine fuel, and starting and preheating the variable compression ratio engine (1);

s4, selecting a standard fuel with a known cetane number to be injected into an air inlet channel, premixing the standard fuel with air, then entering the variable compression ratio engine (1), adjusting the fuel injection quantity and the compression ratio to ensure that the premix of the standard fuel and the air is self-ignited under high pressure, and measuring a phase angle corresponding to a combustion point of the standard fuel and the air through a first sensor, wherein the phase angle is also called a combustion lag period;

s5, adjusting the compression ratio of the variable compression ratio engine (1) to make the ignition lag period be a fixed value, thereby obtaining the corresponding relation between the characteristic compression ratio and the cetane number of the standard fuel;

s6, selecting different types of standard fuels, repeating the step S4 and the step S5 to obtain the corresponding relation between the characteristic compression ratio and the cetane number of the fuel of the different types of standard fuels under the same combustion condition, and establishing a cetane number-characteristic compression ratio curve through mathematical fitting;

s7, selecting the fuel to be tested, repeating the step S4 and the step S5 under the same working condition, obtaining the characteristic compression ratio of the fuel to be tested, and obtaining the cetane number of the fuel to be tested by utilizing the curve from the cetane number to the characteristic compression ratio.

9. The method for determining the cetane number of diesel fuel according to claim 8, wherein for step S1, the intake air temperature is 66 ± 0.5 ℃, the intake air pressure is 1bar, and the set temperature of the mixture is 66 ± 0.5 ℃.

10. The method for determining the cetane number of diesel fuel according to claim 8, wherein the adjustable compression ratio engine adopts a compression ignition mode, and the rotating speed of the adjustable compression ratio engine is 900 +/-9 r/min.

Technical Field

The invention relates to a fuel testing instrument, in particular to a device and a method for determining gasoline octane number and diesel oil cetane number.

Background

The octane number of the gasoline is a digital index for measuring the anti-knock combustion capability of the gasoline in a cylinder, and a high value indicates good anti-knock property. The cetane number of diesel oil is used to indicate the ignition performance of diesel oil.

In the prior art, a direct testing instrument for gasoline octane number and a direct testing instrument for diesel oil cetane number are two different instruments. The gasoline octane number measurement can generally measure motor octane number and research octane number.

Chinese patent No. CN210665722U discloses a device for measuring gasoline octane number, which comprises: bottom plate, detonation intensity detection device, temperature control device, electronic box and operation panel, top one side fixed mounting of bottom plate detonation intensity detection device, detonation intensity detection device includes guide rail, track motor, oil cup, goes out oil pipe and detonation intensity detector, top one side fixed mounting of bottom plate the guide rail, the top fixed mounting of guide rail has the stopper, swing joint on the guide rail the track motor, one side fixed mounting of track motor the oil cup, fixed mounting has level sensor in the oil cup, the bottom intercommunication of oil cup goes out oil pipe.

Chinese patent with publication number CN108613812A discloses a full-automatic determination system and method for diesel cetane number engine, comprising: a signal acquisition and control device; the piston automatic moving device is connected with the signal acquisition and control device through a circuit and realizes the automatic movement of the compression ratio piston of the engine under the control of the signal acquisition and control device; the oil circuit automatic switching device is connected with the signal acquisition and control device through a circuit, and realizes automatic switching or switching-off of an oil inlet cup of the engine under the control of the oil circuit automatic switching device; the automatic oil line cleaning device is connected with the signal acquisition and control device through a circuit and realizes the automatic cleaning of an oil pipe pipeline of the engine under the control of the automatic oil line cleaning device; and the human-computer interaction control device is in communication connection with the signal acquisition and control device and transmits data to realize human-computer interaction operation.

The inventor thinks that when the laboratory detects the gasoline octane number and the diesel oil cetane number, two instruments are needed, the occupied area is large, the investment is high, and a part to be improved exists.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a device and a method for measuring the octane number of gasoline and the cetane number of diesel oil.

The device for measuring the octane number of the gasoline and the cetane number of the diesel comprises a variable compression ratio engine, wherein a first sensor for detecting cylinder pressure and a second sensor for detecting the running phase of the variable compression ratio engine are arranged in the variable compression ratio engine; an intake module in communication with a variable compression ratio engine through an intake passage; the oil injection module is communicated with an air inlet channel between the air inlet module and the variable compression ratio engine; the auxiliary function module is used for exhausting, radiating, filtering and silencing; and the operation control module is used for operating, displaying, measuring and controlling the device.

Preferably, the air intake module comprises a natural air intake unit, a supercharging air intake unit and an air intake arrangement unit, and the air intake arrangement unit is used for filtering, dehumidifying and controlling the temperature of air entering the variable compression ratio engine.

Preferably, the oil spout module includes the oil storage tank group, the oil storage tank group includes standard fuel oil storage tank, the fuel oil storage tank that awaits measuring and heat engine fuel oil storage tank, the oil-out department of standard fuel oil storage tank, the fuel oil storage tank that awaits measuring and heat engine fuel oil storage tank three is connected with the select valve, just the select valve communicates with the nozzle.

According to the present invention, there is provided a method for measuring gasoline octane number, comprising an apparatus for measuring gasoline octane number and diesel cetane number according to claims 1 to 3, the method comprising the steps of: s1, selecting the controllable air inlet module as natural air inlet, setting the temperature, pressure and humidity of the air inlet, setting the temperature of air mixture and setting the ignition advance angle of the variable compression ratio engine; s2, assembling a group of standard fuel with known octane number, fuel to be tested and heat engine fuel in an oil storage tank in the oil injection module; s3, selecting heat engine fuel, and starting and preheating the variable compression ratio engine; s4, selecting a standard fuel with a known octane number to be sprayed into an air inlet channel, premixing the standard fuel with air, then entering the variable compression ratio engine, igniting the premix of the standard fuel with the known octane number and the air to generate detonation, adjusting the fuel injection quantity, and measuring the maximum detonation intensity of the fuel injection quantity through a first sensor; s5, adjusting the engine compression ratio of the variable compression ratio engine to enable the maximum knock intensity to be a fixed value, and obtaining the corresponding relation between the characteristic compression ratio and the standard fuel octane number;

s6, selecting different types of standard fuels, repeating the step S4 and the step S5 to obtain the corresponding relation between the characteristic compression ratio and the fuel octane number of the different types of standard fuels under the same combustion condition, and establishing an octane number-characteristic compression ratio curve through mathematical fitting; s7, selecting the fuel to be tested, repeating the steps S4 and S5 under the same working condition to obtain the characteristic compression ratio of the fuel to be tested, and obtaining the octane number of the fuel to be tested by utilizing the octane number-characteristic compression ratio curve.

Preferably, the octane number of the gasoline comprises motor octane number and research octane number, and for step S1, when the motor octane number is determined, the inlet temperature of the controllable air inlet module is 155 ± 10 ℃, the inlet pressure is normal pressure, the inlet humidity is 3.56-7.12 water/kg dry air, and the set temperature of the mixed gas is 155 ± 10 ℃; when the research octane number is measured, the air inlet temperature of the controllable air inlet module is 52 +/-1 ℃, the air inlet pressure is normal pressure, the air inlet humidity is 3.56-7.12 water/kg dry air, and the set temperature of the mixed air is 52 +/-1 ℃.

Preferably, the variable compression ratio engine has a speed of 900 ± 9r/min when determining the motor octane number; and when the research octane number is measured, the rotating speed of the variable compression ratio engine is 600 +/-6 r/min.

Preferably, for step S1, the spark advance angle of the variable compression ratio engine is 13 °.

According to the invention, a method for determining the cetane number of diesel oil is provided, which comprises the device for determining the octane number and the cetane number of the diesel oil, which is disclosed in the claims 1-3, and the method comprises the following steps: s1, selecting the controllable air inlet module as supercharged air inlet, and setting air inlet temperature, air inlet pressure and air mixture temperature; s2, a group of standard fuel with known cetane number, fuel to be tested and heat engine fuel are filled in an oil storage tank group in the oil injection module; s3, selecting heat engine fuel, and starting and preheating the variable compression ratio engine; s4, selecting a standard fuel with a known cetane number to be injected into an air inlet channel, premixing the standard fuel with air, then entering the variable compression ratio engine, adjusting the fuel injection quantity and the compression ratio to ensure that the premix of the standard fuel and the air is self-ignited under high pressure, and measuring a phase angle corresponding to a combustion point of the standard fuel and the air by a first sensor, wherein the phase angle is also called a firing lag phase; s5, adjusting the compression ratio of the variable compression ratio engine to make the ignition lag period be a fixed value, thereby obtaining the corresponding relation between the characteristic compression ratio and the cetane number of the standard fuel; s6, selecting different types of standard fuels, repeating the step S4 and the step S5 to obtain the corresponding relation between the characteristic compression ratio and the cetane number of the fuel of the different types of standard fuels under the same combustion condition, and establishing a cetane number-characteristic compression ratio curve through mathematical fitting; s7, selecting the fuel to be tested, repeating the step S4 and the step S5 under the same working condition, obtaining the characteristic compression ratio of the fuel to be tested, and obtaining the cetane number of the fuel to be tested by utilizing the curve from the cetane number to the characteristic compression ratio.

Preferably, for step S1, the intake air temperature is 66 ± 0.5 ℃, the intake air pressure is 1bar, and the set temperature of the mixture is 66 ± 0.5 ℃.

Preferably, the adjustable compression ratio engine adopts a compression ignition mode, and the rotating speed of the adjustable compression ratio engine is 900 +/-9 r/min.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention can burn a plurality of groups of standard fuels with known octane number or cetane number in a compressible ratio engine by matching the air inlet module capable of switching natural air inlet and supercharged air inlet with the fuel injection modules capable of storing a plurality of groups of standard fuels with known octane number or cetane number, fuels to be tested and heat engine fuels, establishes an octane number-characteristic compression ratio curve or a cetane number-characteristic compression ratio curve by mathematical fitting, enables the fuels to be tested to burn under the same condition to test the characteristic compression ratio, namely can obtain the octane number or the cetane number of the fuels to be tested according to the octane number-characteristic compression ratio curve or the cetane number-characteristic compression ratio curve, realizes that only one machine is used for testing the octane number of gasoline and the cetane number of diesel, and is beneficial to reducing the floor area of a detection instrument, and contributes to the reduction of investment;

2. according to the invention, the first sensor is used for detecting the cylinder pressure in the variable compression ratio engine, and the second sensor is used for detecting the running phase of the variable compression ratio engine, so that the corresponding relation between the characteristic compression ratio of gasoline or diesel oil and the standard fuel octane number or cetane number in one variable compression ratio engine can be detected, the cost is reduced, and the detection is accurate;

3. the auxiliary function module is matched with the operation control module, so that the stability of the experimental environment of the device is ensured, and the accuracy of the experiment is improved.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic view showing the overall structure of a measuring apparatus according to the present invention.

Shown in the figure:

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

As shown in the figure 1, the device for measuring the octane number of the gasoline and the cetane number of the diesel comprises a variable compression ratio engine 1, an air inlet module 2, an oil injection module 3, an auxiliary function module 4 and an operation control module 5. The air intake module 2 is communicated with the variable compression ratio engine 1 through an air intake passage, and the oil injection module 3 is communicated with the air intake passage between the air intake module 2 and the engine with the compression ratio, so that fuel sprayed by the oil injection module 3 can be mixed with gas in an input device of the air intake module 2 in the air intake passage and then enters the variable compression ratio engine 1.

The variable compression ratio engine 1 is a single-cylinder four-stroke variable compression ratio engine, and the cylinder diameter, the stroke, the rotating speed and the variable compression ratio range of the variable compression ratio engine 1 are required to be specific values. The variable compression ratio engine 1 has a cylinder diameter of 83.0mm, a stroke of 110.0mm, and a variable compression ratio range of 5 to 11. When the octane number of the gasoline motor method and the cetane number of the diesel oil are detected, the rotating speed of the variable compression ratio engine 1 is 900 +/-9 r/min, and is preferably 900 r/min; when the research octane number of gasoline is measured, the rotation speed of the variable compression ratio engine 1 is 600 + -6 r/min, preferably 600 r/min.

The variable compression ratio engine 1 is supplied with oil by adopting an air inlet channel oil injection mode, and the variable compression ratio engine 1 further comprises a first sensor capable of directly measuring the cylinder pressure when the variable compression ratio engine 1 runs, a second sensor capable of detecting the running phase of the variable compression ratio engine 1 and an ignition plug 6 for ignition.

The air inlet module 2 comprises a natural air inlet unit 7, a pressurization air inlet unit 8 and an air inlet arrangement unit 9, a sealing device 10 is installed at an air outlet of the pressurization air inlet unit 8, the sealing device 10 is a sealing plate, and the sealing plate can open or close an air outlet of the pressurization air inlet unit 8 through rotation. When the octane number of gasoline is detected, the natural gas inlet unit 7 works to convey gas into the device, at the moment, the sealing plate seals the gas outlet of the pressurization gas inlet unit 8, and the pressurization gas inlet unit 8 does not work; when the cetane number of diesel oil is detected, the closing plate is opened, the supercharging air inlet unit 8 works and conveys air into the device, and the natural air inlet unit 7 does not work at the moment.

As shown in fig. 1, the air inlet arrangement unit 9 is installed on the air inlet channel, and the air inlet arrangement unit 9 includes a special type-selected dehumidification device and a temperature control combination of a heating rod and a PT100, and can simultaneously complete filtration, dehumidification and temperature control of the inlet air. And then can guarantee that: when testing the octane number of gasoline, the natural inlet air humidity meets the requirement that the humidity is 3.56-7.12 water/kg dry air, the inlet air pressure is normal pressure, and when testing the octane number of a gasoline motor, the inlet air temperature is 155 +/-10 ℃; when testing the research octane number of gasoline, the inlet air temperature is 52 plus or minus 1 ℃; when the cetane number of diesel oil is tested, the supercharging inlet pressure is 1bar, the humidity is not controlled, and the inlet temperature is as follows: 66. + -. 0.5 ℃.

The oil injection module 3 comprises a group of parallel oil storage tanks 11 and a pressure source 12 connected with the same, wherein the output pressure of the pressure source 12 is adjustable at 3-5bar, and the oil injection module comprises a selector valve 13, an oil injection control unit 14 and an oil injection nozzle 15. The oil storage tank group 11 includes a standard fuel oil storage tank for containing standard fuel, a fuel oil storage tank to be tested for containing fuel to be tested, and a heat engine fuel oil storage tank for containing heat engine fuel. The selector valve 13 is connected with a plurality of oil storage tanks, and is connected with an oil injection control unit 14 and an oil injection nozzle 15 in sequence. When the fuel injection control device works, the selection is carried out through the selector valve 13, the fuel in different oil storage tanks is conveyed into the air inlet channel, and the oil injection quantity can be controlled through the oil injection control unit 14. Because the air inlet channel is adopted for injecting oil, the fuel to be measured can be liquid fuel or gas fuel.

The air inlet channel is communicated with the air inlet module 2 and the variable compression ratio engine 1, the air inlet channel is provided with a mixed gas temperature control module 16, and the mixed gas temperature control module 16 comprises a heating belt connected with the operation control module 5 and a temperature control assembly of PT 00. When testing the octane number of a gasoline motor, the temperature of the mixed gas is 155 +/-10 ℃, and when testing the octane number of a gasoline experiment, the temperature of the mixed gas is 52 +/-1 ℃; when the cetane number of diesel oil is tested, the temperature of the mixed gas is 66 +/-0.5 ℃. The variable compression ratio engine 1 is also communicated with an exhaust pipeline and an oil supply pipeline.

The auxiliary function module 4 is connected with the variable compression ratio engine 1 and the operation control module 5, and the auxiliary function module 4 comprises general functions of engine auxiliary heat dissipation, engine lubricating oil temperature control, engine clamping sleeve temperature control, exhaust heat dissipation, filtering, noise reduction and the like. When testing the octane number of gasoline and the cetane number of diesel oil, the temperature of the lubricating oil of the engine is controlled to 57 +/-8 ℃, and the temperature of the clamping sleeve of the engine is controlled to 100 +/-1.5 ℃.

The operation control module 5 is responsible for the functions of operation, display and measurement and control, adjusts the engine to select corresponding rotating speed and ignition mode according to different target parameters (gasoline octane number or diesel cetane number) to be tested, adopts the spark plug 6 for ignition when testing the gasoline octane number, leads the ignition to be 13 degrees in advance, and adopts a compression ignition mode when testing the diesel cetane number. And adjusting the air inlet module 2 to enable the air inlet temperature and the air inlet pressure to be in corresponding specific states, adjusting the controllable oil injection module 3 of the air inlet channel to be in corresponding specific working states, and adjusting related pipelines to be in corresponding specific working states.

The operation control module 5 is the core of the system and is responsible for the functions of operation, display and measurement and control, and guides the test steps in real time to obtain a test result; and meanwhile, the running working condition of the whole device is monitored in real time, and whether the running working condition meets the specified requirements or not is judged. The operation control module 5 is a console including an industrial computer and related circuits, and is responsible for the measurement and control functions of the whole instrument, and is also a human-computer interaction interface of the instrument.

According to the invention, the method for measuring the octane number of the gasoline comprises the device for measuring the octane number of the gasoline and the cetane number of the diesel, and comprises the following steps:

s1, selecting the controllable air inlet module 2 as natural air inlet, and when determining the motor octane number, controlling the air inlet temperature of the controllable air inlet module 2 to be 155 +/-10 ℃, the air inlet pressure to be normal pressure, the air inlet humidity to be 3.56-7.12 water/kg dry air, and the set temperature of the mixed air to be 155 +/-10 ℃; when the research octane number is measured, the air inlet temperature of the controllable air inlet module 2 is 52 +/-1 ℃, the air inlet pressure is normal pressure, the air inlet humidity is 3.56-7.12 water/kg dry air, and the set temperature of the mixed air is 52 +/-1 ℃. And the ignition advance angle of the variable compression ratio engine 1 is set to 13 °.

And S2, filling a group of standard fuel with known octane number in a standard fuel storage tank in the fuel injection module 3, filling the fuel to be tested in a fuel storage tank to be tested and filling the heat engine fuel in a heat engine fuel storage tank.

S3, selecting heat engine fuel, starting the variable compression ratio engine 1 for preheating, and enabling the air inlet temperature, the air inlet humidity, the air inlet pressure, the mixed gas temperature, the engine speed, the engine lubricating oil temperature, the engine jacket temperature and the like of the device to reach the preset range.

S4, selecting a standard fuel with a known octane number to be sprayed into an air inlet channel, premixing the standard fuel with air, then entering the variable compression ratio engine 1, igniting the premix of the standard fuel with the known octane number and the air, generating detonation, adjusting the fuel injection quantity, changing the fuel injection quantity, namely changing the concentration of oil gas in the premix, finding an optimal oil gas concentration according to the engine combustion theory, wherein the detonation intensity is the maximum, and measuring the maximum detonation intensity through a first sensor.

S5, the engine compression ratio of the variable compression ratio engine is adjusted so that the maximum knock intensity is a fixed value, thereby obtaining the correspondence relationship between the characteristic compression ratio and the standard fuel octane number.

S6, selecting different types of standard fuels, repeating the step S4 and the step S5 to obtain the corresponding relation between the characteristic compression ratio and the fuel octane number of the different types of standard fuels under the same combustion condition, and establishing an octane number-characteristic compression ratio curve through mathematical fitting.

S7, selecting the fuel to be tested, repeating the steps S4 and S5 under the same working condition to obtain the characteristic compression ratio of the fuel to be tested, and obtaining the octane number of the fuel to be tested by utilizing the octane number-characteristic compression ratio curve.

According to the invention, the method for measuring the cetane number of the diesel oil comprises the device for measuring the octane number of the gasoline and the cetane number of the diesel oil, and comprises the following steps:

s1, selecting the controllable air inlet module 2 as supercharged air inlet, setting the air inlet temperature to be 66 +/-0.5 ℃, setting the air inlet pressure to be 1bar, and setting the temperature of the mixed air to be 66 +/-0.5 ℃.

S2, filling a set of standard fuel with known cetane number in a standard fuel storage tank in the fuel injection module 3, filling the fuel to be tested in a fuel storage tank to be tested, and filling the fuel for the heat engine in a fuel storage tank for the heat engine.

S3, selecting heat engine fuel, starting the variable compression ratio engine 1 for preheating, and enabling the air inlet temperature, the air inlet humidity, the air inlet pressure, the mixed gas temperature, the engine speed, the engine lubricating oil temperature, the engine jacket temperature and the like of the device to reach the preset range.

S4, selecting a standard fuel with a known cetane number to be injected into an air inlet channel, premixing the standard fuel with air, then entering the variable compression ratio engine 1, adjusting the fuel injection quantity and the compression ratio, setting the fuel injection quantity to be 13ml/min, enabling the pre-mixture of the standard fuel and the air to be self-ignited under high pressure, and measuring a phase angle corresponding to the combustion point of the standard fuel and the air through a second sensor, wherein the phase angle is also called a combustion lag phase.

S5, the compression ratio of the variable compression ratio engine 1 is adjusted so that the ignition lag phase becomes a fixed value of 13 °, whereby the correspondence relationship between the characteristic compression ratio and the standard fuel cetane number is obtained.

S6, selecting different types of standard fuels, repeating the step S4 and the step S5 to obtain the corresponding relation between the characteristic compression ratio and the fuel cetane number of the different types of standard fuels under the same combustion condition, and establishing a cetane number-characteristic compression ratio curve through mathematical fitting.

S7, selecting the fuel to be tested, repeating the step S4 and the step S5 under the same working condition, obtaining the characteristic compression ratio of the fuel to be tested, and obtaining the cetane number of the fuel to be tested by utilizing the curve from the cetane number to the characteristic compression ratio.

Principle of operation

During work, the heat engine fuel is combusted in the variable compression ratio engine 1, and the air inlet temperature, the air inlet humidity, the air inlet pressure, the mixed gas temperature, the engine rotating speed, the engine lubricating oil temperature, the engine holding sleeve temperature and the like of the adjusting device reach the preset range; then, a plurality of groups of standard fuels with known octane numbers or standard fuels with known cetane numbers are combusted under the specific conditions, and the maximum detonation intensity or the ignition lag period of the standard fuels is measured, so that the corresponding relation between the characteristic compression ratio and the standard fuel octane number or the corresponding relation between the characteristic compression ratio and the standard fuel cetane number is obtained, further, an octane number-characteristic compression ratio curve or a cetane number-characteristic compression ratio curve is established through mathematical fitting, finally, the fuel to be measured is selected, the characteristic compression ratio of the fuel to be measured is obtained under the same conditions, and the octane number or the cetane number of the fuel to be measured is obtained by utilizing the octane number-characteristic compression ratio curve or the cetane number-characteristic compression ratio curve.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.