CN102080598B - Control method of combustion engine using dimethyl ether and high-octane rating fuel - Google Patents

Abstract

The invention provides a control method of a combustion engine using dimethyl ether and high-octane rating fuel, relating to a flexible scene mixing mode of dimethyl ether (DME) and high-octane rating fuel combining with a compound mixing combustion mode of ignition and compression ignition. According to the operation working condition of the combustion engine, the combustion mode is selected, and the scene mixing in different ratios is regulated in real time by using the pure DME and high-octane rating fuel so as to meet the requirement of the combustion engine on the fuel under the whole working condition. Under a starting and idling working condition, ignition is carried out by the pure DME; when in 0-30% small load, high-octane rating fuel-DME with high DME mixing ratio is used for carrying out homogeneity premixing and compression ignition; when in 30-70% intermediate load, the high-octane rating fuel-DME mixing fuel with low DME mixing ratio is used for carrying out spark ignition; and when in 70-100% high load, high-octane rating fuel is used for ignition. By using the technology, a combustion engine for a vehicle can reach an emission standard above ohm 4, and an efficient technical way is provided for using and consuming oil and fuel as well as improving engine heat efficiency and fuel oil economy.

Description

A control method for an internal combustion engine using dimethyl ether and high-octane fuel

technical field

The invention provides a control method of an internal combustion engine using dimethyl ether DME and high-octane fuel on-site mixing and compound combustion mode, and specifically relates to a combustion control and operation mode, fuel preparation and supply of the internal combustion engine.

Background technique

With the rapid increase of vehicle ownership, energy consumption and environmental pollution have become the focus of people's attention, and it is also one of the problems that need to be solved urgently. With the development of electronic control technology, traditional gasoline engines and diesel engines have been greatly improved and improved in terms of fuel consumption and exhaust emissions, but they still have their own disadvantages. Due to the stoichiometric equivalent ratio and premixed homogeneous combustion of traditional gasoline engines, NOx and PM emissions are low. At the same time, due to the low compression ratio, the working noise is low, but also due to the limitation and influence of factors such as knocking and low compression ratio, the fuel consumption is large and the thermal efficiency is low. Compared with gasoline engines, the higher compression ratio of diesel engines makes them have higher thermal efficiency and lower fuel consumption. However, the combustion of a traditional diesel engine is the diffusion combustion of fuel spray, relying on the high temperature when the piston of the internal combustion engine is compressed to close to the top dead center to make the mixture spontaneously ignite. Due to the short mixing time of spray and air, the mixture of fuel and air is seriously uneven, forming a high-temperature rich mixture area and a high-temperature flame area, resulting in a large amount of soot and NO _X. At the same time, the high compression ratio also causes the diesel engine to work rough and noisy. The combustion method of homogeneous premixed compression ignition HCCI is to combine the compression ignition of the traditional diesel engine with the premixed homogeneous combustion of the traditional gasoline engine, achieve high thermal efficiency through a high compression ratio, and achieve low emissions through homogeneous premixing. The HCCI internal combustion engine sucks the premixed gas in the intake port into the cylinder during the intake stroke, and when it is compressed to near the top dead center, the homogeneous mixed gas realizes multi-point autoignition and ignition. Due to the lean mixture and homogeneous multi-point combustion at the same time, there is no local high-temperature area on the spark ignition and propagation, and the diffusion combustion peak, so HC, CO, NO _X and PM emissions are very low, and it also has high thermal efficiency. . However, the HCCI combustion method is controlled by the combustion boundary conditions and fuel chemistry, and it is difficult to accurately control the ignition time, so the operating conditions of the whole machine are narrow. Although the current use of electronic control and exhaust after-treatment devices can make gasoline engines achieve extremely low emissions. At the same time, the use of electronically controlled high-pressure common rail and multiple fuel injection technologies with exhaust after-treatment technology also enables diesel engines to achieve very low emissions. The HCCI combustion method can significantly reduce emissions while improving thermal efficiency. However, since the vehicle engine is in a constantly changing and complex process during operation, it is difficult for a single combustion mode and traditional single fuel to meet and adapt to the operating requirements of the engine under all working conditions, resulting in the reduction of emissions while consuming part of the power or increasing fuel consumption. and so on.

Contents of the invention

The present invention adopts the following technical scheme: a control method of an internal combustion engine using on-site mixing and compound combustion mode of dimethyl ether and high-octane fuel, and the on-site mixing and compound combustion mode internal combustion engine of dimethyl ether and high-octane fuel It is transformed from a traditional electronically controlled spark ignition internal combustion engine, including a cylinder 20, an internal combustion engine intake pipe 16, an internal combustion engine exhaust pipe 21, an internal combustion engine piston 19, an ignition module 11, a spark plug 12, an electronic throttle valve 15, and the crank angle signal of the crank angle position sensor 1. The cooling water temperature signal of the cooling water temperature sensor 2. The intake air temperature signal of the intake air temperature sensor 3. The intake air pressure signal of the intake pressure sensor 4. The throttle position signal of the throttle position sensor 5. The knock sensor Combustion pressure and knock signal 6, air-fuel ratio signal 7 of linear oxygen sensor; also includes mixed fuel electronic control unit 8, high-octane fuel tank 9, high-octane fuel pressure regulator 10, high-octane fuel Nozzle 13, DME nozzle 14, DME pressure regulator 17, DME tank 18, mixed fuel ignition control signal a for controlling mixed fuel injection, high octane number fuel injection signal b, DME injection signal c and electronic throttle control signal d;

Crankshaft angle signal from crank angle position sensor 1, cooling water temperature signal from cooling water temperature sensor 2, intake air temperature signal from intake air temperature sensor 3, intake air pressure signal from intake pressure sensor 4, throttle valve from throttle position sensor The position signal 5, the combustion pressure of the knock sensor and the knock signal 6, and the air-fuel ratio signal 7 of the linear oxygen sensor are input into the mixed fuel electronic control unit 8; the mixed fuel electronic control unit 8 is improved on the basis of the existing ECU, On the basis of realizing the original control function, the injection timing and injection pulse width of the mixed fuel dual nozzles are controlled, and the communication, collection and judgment of various signals follow the settings of the original ECU; the mixed fuel electronic control unit 8-way ignition module 11 Send the mixed fuel ignition control signal a to make the spark plug 12 ignite or close, and realize the combined combustion mode of ignition or compression ignition; send the electronic throttle control signal d to the electronic throttle 15 to adjust the opening of the electronic throttle 15, and change the engine's Intake air volume to meet the requirements of different loads and rotational speeds; send a high-octane fuel injection signal b to the high-octane fuel nozzle 13 to realize high-octane fuel injection, and send dimethyl ether injection to the dimethyl ether nozzle 14 Signal c, to realize the injection of dimethyl ether, the injected two fuels are mixed in the intake pipe 16 of the internal combustion engine, and the ratio of the energy of the injected dimethyl ether to the total injected fuel energy is set as α _DME , so as to Indicates the mixing ratio of the two fuels; when the internal combustion engine is in the intake stroke, the mixture of fuel and air is sucked into the cylinder 20 of the internal combustion engine as the piston 19 of the internal combustion engine descends to realize the combustion of the mixture. During the gas stroke, the burned exhaust gas is discharged from the internal combustion engine cylinder 20 through the internal combustion engine exhaust pipe 21 along with the internal combustion engine piston 19; the high octane fuel tank 9, the high octane fuel pressure regulator 10 and the high octane fuel nozzle 13 The high-octane fuel nozzle 13 is fixedly connected to the intake pipe 16 of the internal combustion engine; the dimethyl ether tank 18, the dimethyl ether pressure regulator 17 and the dimethyl ether nozzle 14 are connected in sequence through stainless steel pipes or The pressure-resistant and anti-corrosion hoses are connected sequentially, and the dimethyl ether nozzle 14 is fixedly connected to the intake pipe 16 of the internal combustion engine;

The mixed fuel electronic control unit 8 determines the current speed and load of the engine by reading the crank angle signal 1 of the crank angle position sensor, the throttle position signal 5 of the throttle position sensor, and the intake pressure signal 4 of the intake pressure sensor. Take the cooling water temperature signal 2 from the cooling water temperature sensor, the intake air temperature signal 3 from the intake air temperature sensor, the combustion pressure and knocking signal 6 from the knock sensor, and the air-fuel ratio signal 7 from the linear oxygen sensor, and perform various signal processing Analysis thereby determines the operating conditions under which the engine is operating;

It is characterized in that it includes four control modes: start-idle, low load, medium load and high load:

1) Starting-idling working condition: This working condition is divided into three different situations according to the specific operating environment, which are starting working condition, warm-up working condition and idling working condition; when the engine is in starting-idling working condition, adopt The ignition and combustion method of igniting high cetane number dimethyl ether solely by spark plug ignition;

Starting condition: when the crank angle signal 1 of the crankshaft position sensor shows that the engine speed is higher than 220r/min, the mixed fuel electronic control unit 8 judges that the engine is in the starting condition, and then sends an ignition control signal a to the ignition module 11, and the ignition The module 11 controls the spark plug 12 to flash, and at the same time, the mixed fuel electronic control unit 8 will also send a dimethyl ether injection signal c to the dimethyl ether nozzle 14, so as to realize ignition and starting by pure dimethyl ether;

When the engine is started, the state of the engine at the time of starting is determined according to the cooling water temperature signal 2 of the cooling water temperature sensor and the air-fuel ratio signal 7 of the linear oxygen sensor, and the fuel mixture ratio α, excess air coefficient λ and ignition advance angle are determined according to specific working conditions β; the fuel used in the starting condition is α _DME = 1 pure dimethyl ether, the excess air coefficient λ = 0.5-0.8, and the ignition advance angle β = 6° ATDC; along with the cooling water temperature signal 2 of the cooling water temperature sensor, the engine temperature is displayed As the water temperature continues to increase, the mixed fuel electronic control unit 8 dynamically adjusts the dimethyl ether injection signal c in real time, so that the excess air coefficient λ gradually tends to 1, until the engine water temperature reaches the normal operating range of 90-95°C, and the engine enters a stable idle state;

The starting condition is divided into two states according to the water temperature of the engine:

[1] When the mixed fuel electronic control unit 8 receives the cooling water temperature signal 2 from the cooling water temperature sensor and the water temperature displayed is lower than 30°C, it is judged that the engine is in a cold start condition. Increase the injection amount of dimethyl ether to meet the over-rich mixture of λ=0.5-0.6 required by the engine at cold start; at this time, it is ignited by α _DME =1 pure dimethyl ether, and the excess air coefficient is at λ=0.5 -0.6 rich mixture area;

[2] When the mixed fuel electronic control unit 8 receives the cooling water temperature signal 2 from the cooling water temperature sensor and the water temperature displayed is not lower than 30°C, it is judged that the engine is in the hot engine starting condition, and the required mixture concentration is higher than that of the cold engine start. low time; the mixed fuel electronic control unit 8) adjust the ignition control signal a and the dimethyl ether injection signal c according to the cooling water temperature. At this time, α _DME = 1 pure dimethyl ether is ignited, and the excess air coefficient is at a rich value of λ = 0.6-0.8 mixture area;

Warm-up working condition: when the crankshaft angle signal 1 of the crankshaft position sensor shows that the engine speed is higher than 700r/min, the mixed fuel electronic control unit 8 judges that the engine has started normally, and if the cooling water temperature is lower than 75°C, it is a warm-up Working condition: α _DME = 1 pure dimethyl ether is used to ignite and burn in the warm-up condition, the concentration of the mixed gas is 10%-20% higher than the theoretical equivalent ratio of λ = 1, and the mixed fuel electronic control unit 8 is based on the linear oxygen sensor The air-fuel ratio signal 7 controls the excess air coefficient in the rich mixture region of λ=0.8-1, and gradually reduces the injection amount of dimethyl ether by controlling the dimethyl ether injection signal c as the cooling water temperature increases, so that The gas mixture concentration tends to the stoichiometric concentration;

The mixed fuel electronic control unit 8 sends a mixed fuel ignition control signal a to the ignition module 11 according to the relevant signal, causing the spark plug 12 to flash; sends a dimethyl ether injection signal c to the dimethyl ether nozzle 14; Valve control signal d; by controlling the opening of the electronic throttle valve 15 and the ignition timing, the engine can run stably within the range where the engine cycle variation is less than 10%, and the target speed is set at 1000-1400r/min;

Idle speed condition: when the engine water temperature is higher than 75°C and the mixed fuel electronic control unit 8) determines that the engine is in the idle speed condition according to the sensor signal, it sends a mixed fuel ignition control signal a to the ignition module 11 and causes the spark plug 12 to flash, and at the same time sends The dimethyl ether nozzle 14 sends out a dimethyl ether injection signal c to make it inject dimethyl ether fuel, and sends an electronic throttle control signal d to the electronic throttle valve 15 according to the corresponding signal so that the electronic throttle valve 15 can be adjusted within the range of 0-10%. ; Under idling speed conditions, by α _DME = 1 pure dimethyl ether ignition combustion mode operation, the gas mixture concentration is the stoichiometric ratio concentration, the mixed fuel electronic control unit 8) by delaying or advancing the ignition moment, changing the injection amount of dimethyl ether And the opening of the electronic throttle valve 15 realizes the stable control of the engine idling operation, so that the excess air coefficient λ=1, the ignition advance angle β=0-6°ATDC is adjusted, and the target speed is controlled at 790-800r/min;

The above-mentioned cold engine start, normal start conditions, warm-up conditions and idling conditions should be verified by the test bench to determine the corresponding DME injection amount and ignition timing, so that the engine can start normally without any failure. fire or detonation;

2) Low load condition: when the engine is running at a low load condition of 0-30% of its full load, the homogeneous premixed compression ignition combustion method of high-octane fuel and dimethyl ether is used, and α _DME should be Not less than 30%.

The mixed fuel electronic control unit 8) after determining that the engine belongs to the low-load operation of 0-30% of its full load, first close the ignition module 11 through the mixed fuel ignition control signal a, so that the spark plug 12 stops ignition, and realizes the average charge mixing Combustion mode of compression ignition HCCI; at the same time, the mixed fuel electronic control unit 8) judges the speed and load range according to the signals of each sensor, and adjusts the dimethyl ether injection signal c and the high-octane fuel injection signal b, so that the dimethyl ether nozzle 14 and the high-octane fuel injection signal b The octane number fuel nozzle 13 injects dimethyl ether and high-octane number fuel at an appropriate ratio of α _DME not less than 30%, and the mixed fuel electronic control unit 8) simultaneously sends an electronic throttle valve control signal d to the electronic throttle valve 15 to make the electronic throttle valve Valve 15100% open, to achieve low-load homogeneous mixed fuel compression ignition operation in the engine speed range of 1200-6500r/min, engine full load 0-30%;

When the engine is running in a low-load range, it needs fuel with a low octane number that is easy to burn and explode, so the α _DME that needs to be used should not be less than 30%. On this basis, the combination of dimethyl ether and high octane number is verified and optimized through bench tests The mixing ratio of the fuel and the injection pulse width make the excess air coefficient λ of the mixed fuel between 1-3 to ensure that the engine does not misfire;

3) Medium load condition: when the engine is running at 30-70% of its full load, the spark ignition combustion method of high-octane fuel and dimethyl ether mixed fuel is used, and the α _DME used at this time is less than 30 %;

The mixed fuel electronic control unit 8) after determining that the engine belongs to the medium load operating condition of 30-70% of its full load, connects the ignition module 11 and controls the spark plug 12 to ignite, and the mixed fuel electronic control unit 8) judges the rotational speed and In the load interval, adjust the DME injection signal c and the high-octane fuel injection signal b, so that the DME nozzle 14 and the high-octane fuel nozzle 13 inject DME and high-octane at a ratio of α _DME less than 30%. Value fuel, mixed fuel electronic control unit 8) send electronic throttle valve control signal d to electronic throttle valve 15 at the same time to adjust the throttle valve opening to change between 20-55% in real time, along with the continuous improvement of engine load and speed will be The ignition advance angle β is continuously advanced from 8°BTDC to 40°BTDC, realizing the medium-load operation of the engine at 30-70% of the full load of the engine in the speed range of 1200-6500r/min and the excess air coefficient λ=1; Under the circumstances, the α _DME used is less than 30% to avoid situations such as knocking caused by the low octane number of the fuel.

4) High-load working condition: when the engine is running at a high-load working condition of 70-100% of its full load, the engine burns α _DME = 0 pure high-octane fuel, and adopts the combustion method of spark plug ignition;

The mixed fuel electronic control unit 8) after determining that the engine belongs to the high-load operation, connects the ignition module 11 and controls the spark plug 12 to ignite, and closes the dimethyl ether injection signal c so that the dimethyl ether nozzle 14 stops injecting dimethyl ether, and at the same time sends a high The octane number fuel injection signal b causes the high-octane number fuel nozzle 13 to inject high-octane number fuel, and realizes that α _DME = 0 simply ignites the high-octane number fuel under the high-load working condition of 70-100% of the full engine load;

The mixed fuel electronic control unit 8 sends an electronic throttle control signal d to the electronic throttle 15 at the same time so that the throttle opening can be adjusted in real time between 55-100%. As the engine load and speed continue to increase, the ignition advance angle β is continuously advanced from 8°BTDC to 40°BTDC, and the engine is in the 1200-6500r/min speed range and the excess air coefficient λ=1. The engine full load is 70-100 % high-load operation; on this basis, the bench test was conducted to verify and optimize the injection pulse width and ignition timing of high-octane fuel to ensure that the engine does not experience misfire and knocking.

The high-octane fuel is methanol or ethanol or liquefied petroleum gas or natural gas.

When the mixed fuel electronic control unit 8 detects that the excess air coefficient λ measured by the air-fuel ratio signal 7 from the linear oxygen sensor deviates from the theoretical target value by more than 3%, the mixed fuel electronic control unit 8) re-detects the crankshaft angle position sensor The crank angle signal 1, the throttle position signal 5 of the throttle position sensor and the intake pressure signal 4 of the intake pressure sensor determine the current speed and load of the engine again, and determine the current combustion method and fuel injection ratio; At the same time, by adjusting the PID algorithm to adjust the fuel injection pulse width of the dimethyl ether nozzle 14 and the high-octane fuel nozzle 13, an effective closed-loop control of the excess air coefficient λ in each working condition is realized.

Working process of the present invention: the internal combustion engine is started, and the mixed fuel electric control unit 8 receives the crankshaft angle signal 1 of the crankshaft angle position sensor, the cooling water temperature signal 2 of the cooling water temperature sensor and the throttle position signal 5 of the throttle position sensor to determine that the engine is In the starting condition, the DME nozzle 14 is controlled to inject DME fuel, and at the same time, a mixed fuel ignition control signal a is sent to the ignition module 11 to make the spark plug 12 ignite. In order to ensure fuel ignition, different concentrations of mixed gas are used according to different cooling water temperatures. The air-fuel ratio signal 7 of the sensor shows the excess air ratio, so that it is in the range of λ=0.5-1, and the ignition angle β=0-6° ATDC. With the continuous increase of the cooling water temperature, the excess air coefficient λ can be dynamically changed according to the working conditions by adjusting the DME injection amount until it enters the idle state. In the idling condition, the mixed fuel electronic control unit 8 receives the crank angle signal 1 from the crank angle position sensor, the cooling water temperature signal 2 from the cooling water temperature sensor, the throttle position signal 5 from the throttle position sensor, and the air-fuel ratio signal from the linear oxygen sensor 7. Control the DME nozzle 14 to inject DME fuel, send out the electronic throttle control signal d, and realize the stable idling operation of the internal combustion engine by adjusting the opening degree and ignition angle β of the electronic throttle valve 15, the excess air coefficient λ=1, and the ignition angle β=0 °ATDC. 0-30% low-load working condition, when the mixed fuel electronic control unit 8 judges that the engine currently belongs to 0-30% low-load working condition according to the signals of various sensors, it sends a DME injection signal c to the DME nozzle 14 to make it inject DME, and at the same time The high-octane fuel nozzle 13 sends out a high-octane fuel injection signal b to make it inject high-octane fuel. The mixed fuel electronic control unit 8 stops sending the ignition control signal a to the ignition module 11, turns off the spark plug 12, and at the same time sends out the electronic throttle control signal d to make the electronic throttle 15 fully open, realizing the mixed compression ignition combustion mode of DME and high-octane fuel . In the 30-70% medium load condition, the mixed fuel electronic control unit 8 judges that the engine currently belongs to the 30-70% medium load condition according to the signals of various sensors. At this time, the mixed fuel electronic control unit 8 sends a DME injection signal c to the DME nozzle 14 to make it inject DME, and at the same time sends a high-octane fuel injection signal b to the high-octane fuel nozzle 13 to make it inject high-octane fuel . The mixed fuel electronic control unit 8 sends an ignition control signal a to the ignition module 11, the ignition angle β=18°BTDC, and sends an electronic throttle control signal d. By adjusting the opening of the electronic throttle 15, DME and high-octane fuel are realized. Mixed ignition combustion mode. In the 70-100% high-load working condition, the mixed fuel electronic control unit 8 judges that the engine currently belongs to the 70-100% high-load working condition according to the signals of various sensors. At this time, the mixed fuel electronic control unit 8 closes the DME nozzle 14, opens the high-octane fuel nozzle 13, and injects high-octane fuel. The mixed fuel electronic control unit 8 sends the ignition control signal a to the ignition module 11, the ignition angle β=24°BTDC, sends out the electronic throttle control signal d, and adjusts the opening of the electronic throttle 15 to realize the ignition of pure high-octane fuel combustion mode.

The beneficial effect of the present invention is that, aiming at the shortcomings of traditional ignition and compression ignition internal combustion engines, a control method for the internal combustion engine using on-site mixing and compound combustion mode of dimethyl ether and high-octane fuel is proposed. The internal combustion engine of the present invention adopts an ignition and compression ignition composite mixed combustion mode, and the fuel adopts a flexible on-site mixing mode of DME and high-octane fuel. According to the operating conditions of the internal combustion engine, the combustion mode is selected and pure DME, pure high-octane fuel, and high-octane and DME fuel are used to adjust the on-site mixing of different proportions in real time to meet the fuel requirements of the internal combustion engine under all working conditions.

Using high-octane number and DME fuel on-site mixing technology and compound combustion mode is a convenient and feasible technical route. By controlling the opening and closing of spark plugs, it can meet the requirements of internal combustion engines using compound combustion and mixed fuel on-site mixing in different working conditions, that is, in The α _DME = 1 pure DME ignition combustion mode is adopted under the starting-idling condition to improve the cold start performance of the engine and reduce the emission under the idling condition; 0-30% low load adopts the homogeneous mixed fuel compression ignition combustion with higher α _DME The method is to mix more DME into the high-octane fuel, reduce the cetane number of the mixed fuel through the high-octane fuel, control the ignition moment of DME, and improve the performance of the mixed fuel engine; in the middle of 30-70% In the load area, the ignition combustion method with a lower α _DME is adopted, that is, less DME is mixed into the high-octane fuel to reduce the octane number of the fuel, and the ignition performance of the fuel is improved on the basis of no knocking; at 70- In the 100% high-load area, α _DME = 0 pure high-octane fuel is used to ignite and burn, so that the engine does not appear knocking when it is running at high load. The above-mentioned fuels are mixed on site and conform to the combustion mode, and the flexible control of the octane number and cetane number of the mixed fuel internal combustion engine fuel is realized, which improves the starting performance of the internal combustion engine, reduces fuel consumption and emissions, and becomes a simple and practical technical means to improve the performance of the internal combustion engine .

Description of drawings

Fig. 1 structure and working principle diagram of the present invention

In the figure, 1 crank angle signal of crank angle position sensor; 2 cooling water temperature signal of cooling water temperature sensor; 3 intake air temperature signal of intake air temperature sensor; 4 intake air pressure signal of intake air pressure sensor; 5 throttle position sensor throttle position signal; 6 combustion pressure and knock signal of knock sensor; 7 air-fuel ratio signal of linear oxygen sensor; 8 hybrid fuel electronic control unit; 9 high-octane fuel tank; 10 high-octane fuel pressure regulation 11 ignition module; 12 spark plug; 13 high-octane fuel nozzle; 14 high cetane fuel nozzle; 15 electronic throttle; 16 internal combustion engine intake pipe; 17 high cetane fuel pressure regulator; 18 high ten Hexane number fuel tank; 19 internal combustion engine pistons; 20 internal combustion engine cylinders; 21 internal combustion engine exhaust pipes. Mixed fuel ignition control signal a; high octane fuel injection signal b; high cetane fuel injection signal c; electronic throttle control signal d.

Detailed ways

This embodiment has done following experiment to various working conditions:

The experimental internal combustion engine is an in-line 4-cylinder 1.6L EFI gasoline engine, which is transformed into a DME and high-octane fuel on-site mixed load combustion mode internal combustion engine as shown in Figure 1. The high-octane fuel used in the experiment is methanol CH ₃ . A Horiba-7100DEGR emission analyzer produced by Horiba Co., Ltd. was used to measure the HC, CO and NO _x emissions of the internal combustion engine under various operating conditions.

1. Start experiment

Start the engine, and the mixed fuel electronic control unit 8 determines the injection amount of DME and the mixture gas concentration according to the temperature indicated by the cooling water temperature signal 2 of the cooling water temperature sensor. The experimental results show that when the cooling water temperature signal 2 is 0.3V, the cooling water temperature is 10-12°C, the intake air temperature signal 3 is 0.4V, the intake air temperature is 14-15°C, and the intake air pressure signal 4 is 3.7V. The air pressure is 0.91 bar, the mixed fuel electronic control unit 8 sends an ignition control signal a (4.1V) to the ignition module 11, the ignition angle β=6°ATDC, and sends a DME injection signal c (2.3V) to the DME nozzle 14 at the same time, so that It injects DME into the intake port with an injection volume of 8.62L/min. At this time, the throttle position signal 5 is 0.1V, the throttle opening is 3%, and the engine starts to burn normally. At this time, the air-fuel ratio signal of the linear oxygen sensor is 7 It is 2.3V, and the excess air coefficient λ is 0.71, which belongs to the condition of cold engine start and rich mixture.

In the test, the HC emission measured by the Horiba-7100DEGR emission analyzer is 768ppm, the CO emission is 0.51%, and the NO _x emission is 11ppm. This compares to HC emissions of 2101ppm, CO emissions of 1.08%, _and NO _x emissions of 34ppm with the single-fuel isooctane _C8H18 ignition. The reason is that DME is a fuel with a high cetane number, and its flash point is -24°C. It not only has good ignition performance, but is also easy to ignite. The alkane is greatly improved, the starting is easy, the combustion is rapid, and the emission is greatly reduced.

2. Warm-up experiment n=1000-1800r/min, cooling water temperature 13-75℃, throttle opening 3-10%

After the engine is started, the mixed fuel electronic control unit 8 measures the current water temperature as 13-15°C when the cooling water temperature signal 2 of the cooling water temperature sensor is 0.4V, the intake air temperature signal 3 is 0.4V, and the intake air temperature is 14-15°C. ℃, the intake air pressure signal 4 is 3.7V, and the intake air pressure is 0.91 bar, so it is judged that the engine is currently in the warm-up mode, and continues to send the ignition control signal a (4.1V) to the ignition module 11, and the ignition angle β=6°ATDC , and at the same time send a DME injection signal c (2.1V) to the DME nozzle 14, so that it injects DME into the intake port with an injection volume of 7.48L/min, and the engine runs normally. At this time, the throttle position signal 5 is 0.5V, and the throttle valve The air-fuel ratio signal 7 of the linear oxygen sensor with an opening of 10% is 2.6V, the excess air coefficient λ is 0.85, and the target speed of the engine is set at 1800r/min. With the engine running in the warm-up condition, the cooling water temperature signal 2 of the cooling water temperature sensor increases from 0.4V to 3.8V, indicating that the engine temperature gradually rises to 70-73°C, other signals remain unchanged, and the mixed fuel electric The control unit 8 gradually reduces the DME injection signal c (1.6V) of the DME injection amount, so that it injects DME into the intake port with an injection amount of 7.08L/min, so that the mixture concentration gradually decreases. At this time, the throttle position signal 5 is 0.1V, the throttle opening is 3%, the engine starts to burn normally, at this time the air-fuel ratio signal 7 of the linear oxygen sensor is 3.1V, the excess air coefficient λ is 0.94, and the target engine speed is set at 1000r/min.

3. Idle speed test n=790-800rpm, cooling water temperature>75℃, throttle opening 6-8%

When the engine cooling water temperature signal 2 is 3.9V and the current cooling water temperature reaches 75°C, the intake air temperature signal 3 is 0.6V, the intake air temperature is 20-23°C, the intake air pressure signal 4 is 3.7V, and the intake air pressure is 0.91bar, the mixed fuel electronic control unit 8 judges that the engine is currently in the idling condition, and continues the pure DME ignition combustion mode. The mixed fuel electronic control unit 8 sends an ignition control signal a (3.7V) to the ignition module 11, and the ignition angle β=0°ATDC, and at the same time sends a DME injection signal c (1.4V) to the DME nozzle 14 to make it burn at 6.7L/min DME is injected into the air intake port with the injection amount of DME, and the engine runs normally. At this time, the excess air coefficient λ is 1, and the mixed fuel electronic control unit 8 sends an electronic throttle control signal d (0.3V) to the electronic throttle 15 to adjust the electronic throttle. The opening of the valve 15 reaches 6-8%. At this time, the throttle position signal 5 is 0.3V, the throttle opening is 7%, and the engine is running at normal idle speed. At this time, the air-fuel ratio signal 7 of the linear oxygen sensor is 3.5V. The coefficient λ is 1.01, and the target speed of the engine is set at 791r/min.

The experimental results in the idling stage show that the pure DME ignition combustion mode, the actual average engine speed is 791r/min, and the speed cycle variation COVn<5%. The Horiba-7100DEGR emission analyzer measured HC emissions as 834ppm, CO emissions as 0.47%, and _NOx emissions as 20ppm. This compares to 3326ppm HC emissions, 0.531% CO emissions and 87ppm _NOx emissions with _a single fuel isooctane _C8H18 ignition. The engine needs an easy-to-burn fuel under idling conditions. DME’s high cetane number, low-temperature oxidation heat release, and oxygen content make it possible to improve in-cylinder combustion, improve engine efficiency and reduce emissions under idling conditions. .

4. Low load experiment n=1400rpm, cooling water temperature=90℃, throttle opening 100%

When the mixed fuel electronic control unit 8 measures the engine cooling water temperature signal 2 at 4.4V, after the current cooling water temperature reaches 90°C, the intake air temperature signal 3 is 0.9V, the intake air temperature is 25-26°C, and the intake air pressure signal 4 is 3.7V, the intake pressure is 0.91bar, the throttle position signal 5 is 1V, the throttle opening is 20%, and when it is judged that the engine currently belongs to the 0-30% low load condition, the DME injection signal c is sent to the DME nozzle 14 ( 1.2V), so that it injects DME into the engine intake pipe 16 at a flow rate of 6.9L/min, and at the same time sends a high-octane fuel injection signal b (1.1V) to the high-octane fuel nozzle 13, making it flow at 2.81kg/min The flow rate of h injects methanol into the intake pipe 16. The mixed fuel electronic control unit 8 stops sending the ignition control signal a (0V) to the ignition module 11, turns off the spark plug 12, and at the same time sends out the electronic throttle control signal d (5V) to fully open the electronic throttle 15, and the throttle position signal 5 is 5V , to realize the mixed compression ignition combustion mode of DME and methanol. The engine is running normally.

The experimental results show that the crankshaft angle signal 1 is 0.8V, the internal combustion engine speed is 1400rpm, according to the above high-octane number fuel and high cetane number fuel injection amount, the Horiba-7100DEGR emission analyzer measures HC emission as 455ppm, and CO emission as 0.35%, _NOx emissions are 566ppm. This compares to HC emissions of 677ppm, CO emissions of 0.51%, and _NOx emissions of _512ppm with single-fuel isooctane _C8H18 ignition. When the homogeneous mixture compression ignition combustion method is adopted, the mixed gas explodes and burns at multiple points in the cylinder simultaneously, and the excess air coefficient λ>1, so the emission is reduced and the thermal efficiency is increased.

5.30-70% medium load test n=2000rpm, cooling water temperature=95℃, throttle opening 35%

With the increase of the engine speed and load, the mixed fuel electronic control unit 8 measures that the current cooling water temperature reaches 95°C when the engine cooling water temperature signal 2 is 4.6V, the intake air temperature signal 3 is 0.9V, and the intake air temperature is 25- 26°C, intake pressure signal 4 is 3.7V, intake pressure is 0.91bar, throttle position signal 5 is 1.4V, throttle opening is 35%, it is judged that the engine is currently in the 30-70% medium load condition. At this time, the mixed fuel electronic control unit 8 sends a DME injection signal c (0.3V) to the DME nozzle 14, injects DME into the engine intake pipe 16 with a flow rate of 2.2L/min, and sends a high-octane number fuel nozzle 13 to the high-octane number Fuel injection signal b (1.9V), methanol is injected into the intake pipe 16 at a flow rate of 4.8kg/h. The mixed fuel electronic control unit 8 sends an ignition control signal a (2.2V) to the ignition module 11, the ignition angle β=18°BTDC, and realizes the mixed ignition combustion mode of DME and methanol. The engine is running normally, the air-fuel ratio signal 7 of the linear oxygen sensor is 3.5V, and the excess air coefficient λ is 1.01.

The results of the medium load test show that the crankshaft angle signal 1 is 1.3V, the internal combustion engine speed is 2000rpm, according to the above high-octane fuel and DME fuel injection quantity, the Horiba-7100DEGR emission analyzer measures 454ppm of HC emission and 0.48% of CO emission , NO _x emission is 513ppm. Combustion pressure and detonation signal 6 are 0.1V, and the cycle variation is less than 2%. This compares to HC emissions of 423ppm, CO emissions _of 0.51%, and _NOx emissions of 392ppm with single-fuel isooctane _C8H18 ignition. When the engine is running at a medium load, the octane number of the fuel needs to be increased to prevent knocking, but at the same time, in order to ensure that the fuel is easy to burn, it is necessary to mix a lower proportion of DME to improve the overall ignition performance of the fuel. HC and CO emissions are further reduced, but _NOx emissions are increased.

6. 70-100% high load test n=4500r/min, cooling water temperature 95°C, throttle opening 75%

With the increase of the engine speed and load, the mixed fuel electronic control unit 8 measures that the current cooling water temperature reaches 95°C when the engine cooling water temperature signal 2 is 4.6V, the intake air temperature signal 3 is 0.9V, and the intake air temperature is 25- 26°C, intake pressure signal 4 is 3.7V, intake pressure is 0.91bar, throttle position signal 5 is 3.8V, throttle opening is 75%, it is judged that the engine is currently under 70-100% high load condition. At this time, the mixed fuel electronic control unit 8 sends a DME injection signal c (0V) to the DME nozzle 14 to close the DME nozzle 14, open the high-octane fuel nozzle 13, and send a high-octane fuel injection signal to the high-octane fuel nozzle 13 b (2.6V), spray methanol into the intake port at a flow rate of 6.3kg/h. The mixed fuel electronic control unit 8 sends an ignition control signal a (1.9V) to the ignition module 11, the ignition angle β=24°BTDC, and the pure methanol ignition combustion mode is realized. The engine is running normally, and the air-fuel ratio signal 7 of the linear oxygen sensor is 3.5V, and the excess air coefficient λ is 1.

The experimental results show that the crank angle signal 1 is 2.9V, the internal combustion engine speed is 4500r/min, and the internal combustion engine power is 74.2kW, while the original gasoline engine is 75.3kW. Combustion pressure and detonation signal 6 are 0.1V, and the cycle variation is less than 2%. The Horiba-7100DEGR emission analyzer measured 222ppm of HC emissions, 0.21% of CO emissions and 677ppm of NO _x emissions. That compares to 254ppm HC emissions, 0.34% _CO emissions and 339ppm _NOx emissions with the single-fuel isooctane _C8H18 . When running at high load, fuel with better anti-knock performance is required to participate in the combustion. The octane number of methanol exceeds 110, so it can effectively avoid the occurrence of engine knocking caused by excessive load. The use of pure methanol ignition mode under high load conditions can make the engine run normally and reasonably within the range of working conditions, and effectively reduce problems such as cycle fluctuations and emissions. At the same time, because DME is an oxygen-containing fuel, the HC and CO emissions are further reduced, but the _NOx emissions are greatly increased due to the increase of the combustion temperature in the cylinder.

Through the bench test of dimethyl ether and high-octane fuel on-site mixing and compound combustion mode internal combustion engine, the results show that the present invention provides a control method for dimethyl ether and high-octane fuel on-site mixing and compound combustion mode internal combustion engine , can run under all working conditions and speeds, and achieve low emissions and high efficiency in a wide range of speeds and loads. Compared with single high-octane fuel ignition, the internal combustion engine has obvious improvement in idling speed, low load and medium load working conditions. This technology will provide an effective technical way for the vehicle internal combustion engine to meet the emission standard above Euro 4 while reducing the use and consumption of oil and fuel.

Claims (3)

1. controlling method that adopts the internal-combustion engine of dimethyl ether and antiknock gasoline mixed on site and compound combustion pattern; Described dimethyl ether and antiknock gasoline mixed on site and compound combustion pattern internal-combustion engine are formed by the automatically controlled spark-ignition internal combustion engine transformation of tradition, comprise firing pressure and the detonation signal (6) of throttle position signal (5), the detonation sensor of suction pressure signal (4), the TPS of intake air temperature signals (3), the air inlet pressure sensor of cooling water temperature signal (2), the intake air temperature sensor of corner signal (1), the cooling-water temperature sensor of cylinder (20), intake lines of combustion engines (16), internal-combustion engine vent-pipe (21), internal combustion engine (19), ignition module (11), spark plug (12), electronic throttle (15) and CAP sensor, the air fuel ratio signal (7) of linear oxygen sensors; The hybrid fuel ignition control signal (a), antiknock gasoline injection signal (b), dimethyl ether injection signal (c) and the Electronic Throttle Control signal (d) that also comprise fuel combination electronic control unit (8), antiknock gasoline case (9), antiknock gasoline pressure regulator (10), antiknock gasoline nozzle (13), dimethyl ether nozzle (14), dimethyl ether pressure governor (17), dimethyl ether jar (18) and control hybrid fuel jet simultaneously;

Fuel combination electronic control unit (8) is advanced in air fuel ratio signal (7) input of the firing pressure of the suction pressure signal (4) of the cooling water temperature signal (2) of the corner signal of CAP sensor (1), cooling-water temperature sensor, the intake air temperature signals (3) of intake air temperature sensor, air inlet pressure sensor, the throttle position signal (5) of TPS, detonation sensor and detonation signal (6), linear oxygen sensors; Fuel combination electronic control unit (8) is on the basis of existing ECU, to improve; On the basis of realizing original control function, the time for spraying and the injection pulse width of fuel combination twin nipple are controlled, the setting of former machine ECU is followed in the communication of various signals, collection and judgement; Fuel combination electronic control unit (8) sends hybrid fuel ignition control signal (a) to ignition module (11) makes spark plug (12) get angry or close, and realizes lighting or the compound combustion pattern of compression ignite; Send the aperture of Electronic Throttle Control signal (d) to electronic throttle (15), change the air inflow of motor, realize the requirement of different load and rotating speed with adjustment electronic throttle (15); Send antiknock gasoline injection signal (b) to antiknock gasoline nozzle (13); Realize the injection of antiknock gasoline; Send dimethyl ether injection signal (c) to dimethyl ether nozzle (14); Realize the injection of dimethyl ether, two kinds of fuel of injection mixed on site in intake lines of combustion engines (16) accounts for the ratio that always sprays into fuel energy with the energy of the dimethyl ether that sprays into and is set at α _DME, show the mixed proportion of two kinds of fuel with this; When internal-combustion engine is in aspirating stroke; Go into cylinder of internal-combustion engine (20) along with being about to fuel and Air mixing aspiration under the internal combustion engine (19); Realize the burning of mixed gas; Behind overcompression, expansion stroke, the waste gas that when exhaust stroke, will burn is discharged cylinder of internal-combustion engine (20) with the up internal-combustion engine vent-pipe (21) that passes through of internal combustion engine (19); Antiknock gasoline case (9), antiknock gasoline pressure regulator (10) and antiknock gasoline nozzle (13) are connected through Stainless Steel Tube or pressure hose successively, and antiknock gasoline nozzle (13) is connected on the intake lines of combustion engines (16); Dimethyl ether jar (18), dimethyl ether pressure governor (17) and dimethyl ether nozzle (14) are connected through Stainless Steel Tube or withstand voltage corrosion protection flexible pipe successively, and dimethyl ether nozzle (14) is connected on the intake lines of combustion engines (16);

Fuel combination electronic control unit (8) is confirmed rotating speed and the load that motor is current through the corner signal (1) that reads the CAP sensor, the throttle position signal (5) of TPS and the suction pressure signal (4) of air inlet pressure sensor; Read the cooling water temperature signal (2) of cooling-water temperature sensor, the intake air temperature signals (3) of intake air temperature sensor, the firing pressure of detonation sensor and the air fuel ratio signal (7) of detonation signal (6) and linear oxygen sensors simultaneously, confirm the operating mode that motor is moved thus through various signals are analyzed;

It is characterized in that: comprised starting-idling, low-load, middle load and four kinds of control modes of high load:

1) starting-idling operation: this operating mode is divided into three kinds of condition of different according to concrete running environment, is respectively state of starting operating, warming-up operating mode and idling operation; When motor is in starting-idling operation, adopt the ignition combustion mode that relies on plug ignition to light the high cetane number dimethyl ether separately;

State of starting operating: when the corner signal (1) of crankshaft position sensor shows that the rotating speed of motor is higher than 220r/min; Fuel combination electronic control unit (8) judges that motor is in state of starting operating; Send ignition control signal (a) to ignition module (11) afterwards; By the arcing of ignition module (11) control spark plug (12), fuel combination electronic control unit (8) also will send dimethyl ether injection signal (c) to dimethyl ether nozzle (14) simultaneously, realize lighting starting by pure Dimethyl ether;

The state of motor when confirming starting according to the air fuel ratio signal (7) of the cooling water temperature signal (2) of cooling-water temperature sensor and linear oxygen sensors during engine start, and confirm fuel mixture ratio α, air excess factor and ignition advance angle β according to concrete operating mode; Fuel adopts α during state of starting operating _DME=1 pure Dimethyl ether, air excess factor=0.5-0.8, ignition advance angle β=6 ° ATDC; The water temperature that shows motor along with the cooling water temperature signal (2) of cooling-water temperature sensor improves constantly; Fuel combination electronic control unit (8) Real-time and Dynamic adjustment dimethyl ether injection signal (c); Make air excess factor be tending towards 1 gradually; Reach 90-95 ℃ normal range of operation until engine water temperature, motor gets into the idling steady state simultaneously;

State of starting operating is divided into two states according to the water temperature of motor:

[1] when fuel combination electronic control unit (8) receives water temperature that the cooling water temperature signal (2) of cooling-water temperature sensor shown and is lower than 30 ℃; Judge that motor is the cold post-start operating mode; Should improve the dimethyl ether straying quatity this moment according to concrete cooling water temperature, to satisfy the Over-rich mixture of motor needed λ=0.5-0.6 when the cold post-start; This moment is by α _DME=1 pure Dimethyl ether is lighted, and excess air coefficient is in the Over-rich mixture zone of λ=0.5-0.6;

[2] when fuel combination electronic control unit (8) received water temperature that the cooling water temperature signal (2) of cooling-water temperature sensor shown and is not less than 30 ℃, the judgement motor was a hot-start situation, and needed mixture strength is low during than cold post-start; Fuel combination electronic control unit (8) is according to coolant water temperature adjustment ignition control signal (a) and dimethyl ether injection signal (c), and this moment is by α _DME=1 pure Dimethyl ether is lighted, and excess air coefficient is in the rich mixture zone of λ=0.6-0.8;

The warming-up operating mode: when the corner signal (1) of crankshaft position sensor showed that the rotating speed of motor is higher than 700r/min, fuel combination electronic control unit (8) was judged motor normal starting, if this moment, coolant water temperature was lower than 75 ℃ then belong to the warming-up operating mode; Under the warming-up operating mode, adopt α _DME=1 pure Dimethyl ether ignition combustion mode; Mixture strength is higher than the theoretical equivalent proportion 10%-20% of λ=1; Fuel combination electronic control unit (8) is controlled at the regional than rich mixture of λ=0.8-1 according to the air fuel ratio signal (7) of linear oxygen sensors with excess air coefficient; And along with the raising of coolant water temperature through control dimethyl ether injection signal (c), reduce the dimethyl ether straying quatity gradually, make mixture strength be tending towards the stoichiometry specific concentration;

Fuel combination electronic control unit (8) sends hybrid fuel ignition control signal (a) according to coherent signal to ignition module (11), makes spark plug (12) arcing; Send dimethyl ether injection signal (c) to dimethyl ether nozzle (14); Send Electronic Throttle Control signal (d) to electronic throttle (15) simultaneously; Through control electronic throttle (15) aperture and time of ignition make motor can stable operation in engine cycles changes less than 10% scope, rotating speed of target is set in 1000-1400r/min;

Idling operation: when engine water temperature is higher than 75 ℃; Fuel combination electronic control unit (8) is when confirming that according to sensor signal motor belongs to idling operation; Send hybrid fuel ignition control signal (a) and make spark plug (12) arcing to ignition module (11); Send dimethyl ether injection signal (c) to dimethyl ether nozzle (14) simultaneously and make it spray dimethyl ether fuel, send Electronic Throttle Control signal (d) according to corresponding signal to electronic throttle (15) and make electronic throttle (15) in 0-10% interval, adjust; Under idling operation, by α _DME=1 pure Dimethyl ether ignition combustion mode operation; Mixture strength is the stoichiometry specific concentration; Fuel combination electronic control unit (8) is realized the stable control for the engine idle operation through postponement or the premature ignition moment, change dimethyl ether emitted dose and electronic throttle (15) aperture; Make air excess factor=1, ignition advance angle β=0-6 ° ATDC encloses interior adjustment, and rotating speed of target is controlled at 790-800r/min simultaneously;

Above-described cold post-start, normal starting operating mode, warming-up operating mode and idling operation all should carry out demonstration test through stand, confirm corresponding dimethyl ether emitted dose and time of ignition, make motor not occur catching fire or pinking by normal starting;

2) running on the lower load: when the running on the lower load of engine running, adopt the homogeneous homogeneous charge compression ignition combustion manner of antiknock gasoline and dimethyl ether, at this moment α at its full load 0-30% _DMEShould be not less than 30%.

Fuel combination electronic control unit (8) is after confirming that motor belongs to the running on the lower load operation of its full load 0-30%; At first close ignition module (11) through hybrid fuel ignition control signal (a); Make spark plug (12) stop igniting, realize the combustion mode of average charge mixing and compressed ignition HCCI; Fuel combination electronic control unit (8) judges that according to each sensor signal between rotating speed and loading zone, adjustment dimethyl ether injection signal (c) and antiknock gasoline injection signal (b) make dimethyl ether nozzle (14) and antiknock gasoline nozzle (13) press α simultaneously _DMEBe not less than 30% proper proportion injection dimethyl ether and antiknock gasoline; Fuel combination electronic control unit (8) sends Electronic Throttle Control signal (d) to electronic throttle (15) simultaneously opens electronic throttle (15) 100%, realize motor in 1200-6500r/min rotating speed interval, the low-load homogeneous fuel combination compression ignite operation of full engine load 0-30%;

Motor needs the low fuel that is easy to combustion explosion of octane value when operating between low load region, therefore need the α that adopts _DMEShould be not less than 30%; Through the mixed proportion and the injection pulse width of stand test checking and optimization dimethyl ether and antiknock gasoline, the air excess factor that makes fuel combination guarantees that situation such as catching fire does not appear in motor take place between 1-3 on this basis;

3) load condition in: when the middle load condition of engine running, adopt antiknock gasoline and dimethyl ether mixed fuel spark ignition combustion manner, the α of employing this moment at its full load 30-70% _DMELess than 30%;

Fuel combination electronic control unit (8) is after confirming that motor belongs to the middle load condition operation of its full load 30-70%; Be communicated with ignition module (11) and control spark plug (12) igniting; Fuel combination electronic control unit (8) is judged between rotating speed and loading zone according to each sensor signal; Adjustment dimethyl ether injection signal (c) and antiknock gasoline injection signal (b); Make dimethyl ether nozzle (14) and antiknock gasoline nozzle (13) spray dimethyl ether and antiknock gasoline less than 30% ratio in α DME; Fuel combination electronic control unit (8) sends Electronic Throttle Control signal (d) to electronic throttle (15) simultaneously to be changed between 20-55% with real-time adjustment throttle opening; Along with engine load and improving constantly of rotating speed ignition advance angle β constantly is advanced to 40 ° of BTDC by 8 ° of BTDC, realizes the middle load operation of motor full engine load 30-70% in 1200-6500r/min rotating speed interval, under air excess factor=1 situation; The α DME that under this operating mode, adopts is to avoid crossing the low situation such as pinking that causes and taking place owing to fuel octane number less than 30%.

4) high load operating mode: when the high load operating mode of engine running at its full load 70-100%, engine for combusting α _DME=0 pure antiknock gasoline, and the combustion manner of employing spark ignitor;

Fuel combination electronic control unit (8) is after definite motor belongs to the operation of high load operating mode; Be communicated with ignition module (11) and control spark plug (12) igniting; Closing dimethyl ether injection signal (c) makes dimethyl ether nozzle (14) stop to spray dimethyl ether; Send antiknock gasoline injection signal (b) simultaneously and make antiknock gasoline nozzle (13) spray antiknock gasoline, be implemented in α under the high load operating mode of full engine load 70-100% _DME=0 lights antiknock gasoline merely;

Fuel combination electronic control unit (8) simultaneously electronic throttle (15) is sent Electronic Throttle Control signal (d) so that throttle opening adjustment in real time between 55-100%; On the basis that all uses antiknock gasoline; Along with engine load and improving constantly of rotating speed ignition advance angle β constantly is advanced to 40 ° of BTDC by 8 ° of BTDC, realizes the high load running of motor full engine load 70-100% in 1200-6500r/min rotating speed interval, under air excess factor=1 situation; On this basis through stand test checking and optimize the injection pulse width and the time of ignition of antiknock gasoline, guarantee that the motor situation such as pinking that do not occur catching fire takes place.

2. a kind of controlling method that adopts the internal-combustion engine of dimethyl ether and antiknock gasoline mixed on site and compound combustion pattern according to claim 1 is characterized in that described antiknock gasoline is methyl alcohol or ethanol or LPG or rock gas.

3. a kind of controlling method that adopts the internal-combustion engine of dimethyl ether and antiknock gasoline mixed on site and compound combustion pattern according to claim 1; It is characterized in that: depart from 3% when above when fuel combination electronic control unit (8) detects from the measured air excess factor of the air fuel ratio signal (7) of linear oxygen sensors and theory target value; Fuel combination electronic control unit (8) detects the corner signal (1) of CAP sensor, the throttle position signal (5) of TPS and suction pressure signal (4) and the definite once more current rotating speed and load of motor of air inlet pressure sensor again, and confirms the injection proportion of current combustion manner and fuel with this; Regulate the effective closed-loop control of the fuel injection pulsewidth realization of dimethyl ether nozzle (14) and antiknock gasoline nozzle (13) through the adjustment pid algorithm simultaneously to each operating mode air excess factor.

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