WO2016078175A1

WO2016078175A1 - Method and system for controlling fuel injection quantity of ethyl alcohol flexible fuel engine

Info

Publication number: WO2016078175A1
Application number: PCT/CN2014/093930
Authority: WO
Inventors: 李财宝; 李�杰; 胡俊勇; 何博; 曹慧颖; 杨越; 胡福建
Original assignee: 安徽江淮汽车股份有限公司
Priority date: 2014-11-17
Filing date: 2014-12-16
Publication date: 2016-05-26
Also published as: BR112017010306A2; CN104481716B; CN104481716A

Abstract

A method for controlling the fuel injection quantity of an ethyl alcohol flexible fuel engine. The method comprises: collecting the air intake of an engine intake manifold; collecting the engine speed and the engine coolant temperature to obtain the target air-fuel ratio by looking up a table; calculating the running fuel evaporation in an engine running process according to a preset period; calculating the target fuel injection quantity of the engine according to the air intake, the target air-fuel ratio and the running fuel evaporation; and controlling the fuel injection of the engine according to the target fuel injection quantity. Also provided is a system for controlling the fuel injection quantity of an ethyl alcohol flexible fuel engine. By means of the method and system for controlling the fuel injection quantity of an ethyl alcohol flexible fuel engine, the fuel injection quantity of the engine can be accurately controlled according to the running fuel evaporation in the engine running process.

Description

Method and system for controlling fuel injection quantity of ethanol flexible fuel engine

Technical field

The invention relates to the technical field of automobile electronics, in particular to a method and a system for controlling the fuel injection amount of an ethanol flexible fuel engine.

Background technique

Fuel ethanol is a new clean energy source derived from the fermentation of sugar-rich crops. Ethanol flexible fuel, commonly referred to as ethanol fuel, can be obtained by adding fuel ethanol to a gasoline component in a certain volume ratio and compounding it by a specific process. Compared with traditional fuels, ethanol fuel can not only reduce the dependence on non-renewable resources such as petroleum, but also has the following advantages: fuel ethanol combustion products are water and carbon dioxide, high environmental performance; high octane number, good antiknock performance; High volume, is conducive to full combustion; and convenient for storage and transportation. According to the ratio of gasoline to ethanol, ethanol fuel can be divided into many different specifications.

Ethanol Flexible Fuel Vehicles are vehicles that can adapt to any type of ethanol fuel (the ratio of gasoline to ethanol in the fuel can be changed at will). In the process of using ethanol flexible fuel vehicles, the ethanol content is changed due to the different specifications of the ethanol fuel added before and after, and the ratio of fuel injection to ethanol is not suitable, resulting in deterioration of combustion and exhaust in the automobile. Increased pollutants. Therefore, it is necessary to accurately control the fuel injection amount of the ethanol flexible fuel engine based on the actual ethanol content in the combustible mixture.

In the prior art, self-learning of the ethanol content is usually carried out by directly adding an ethanol content sensor to the fuel tank, directly detecting the ethanol content, or by detecting the vehicle exhaust. After obtaining the ethanol content in the ethanol fuel, the air-fuel ratio can be determined according to the ethanol content, and the fuel injection amount can be further calculated according to the intake air amount, which can be calculated according to the formula: fuel injection amount = intake air amount / air-fuel ratio. Among them, the air-fuel ratio refers to the ratio of air quality and fuel quality in the combustible mixture (the fuel quality refers to the mass sum of ethanol and gasoline).

In practice, in order to meet the cold start requirements of ethanol flexible fuel engines, it is necessary to increase the supply of ethanol fuel to form a richer mixture. In this process, a large amount of ethanol enters the crankcase through the piston ring and dissolves into the oil. This condition is often referred to as fuel dilution. When the oil temperature rises, part of the ethanol dissolved in the oil will evaporate and enter the intake air through the crankcase forced ventilation system. The tube has an influence on the air-fuel ratio of the combustible mixture, so that the ethanol content obtained by the prior art method for detecting the ethanol content is inaccurate, and the calculated fuel injection amount does not meet the actual needs.

Summary of the invention

The embodiment of the invention provides a method and a system for controlling the fuel injection amount of an ethanol flexible fuel engine, which can accurately control the fuel injection amount of the engine according to the running fuel evaporation amount during the engine operation.

The technical solution provided by the embodiment of the present invention is as follows:

In one aspect, a method for controlling fuel injection amount of an ethanol flexible fuel engine is provided, comprising:

Collecting the intake air amount of the engine intake manifold;

According to the engine speed and the engine coolant temperature, look up the table to get the target air-fuel ratio;

Calculate the amount of running fuel evaporation during engine operation according to a preset period;

Calculating a target fuel injection amount of the engine according to the intake air amount, the target air-fuel ratio, and the operating fuel evaporation amount;

The engine is controlled to inject oil in accordance with the target injection amount.

Preferably, the calculating the amount of running fuel evaporation during engine operation according to a preset period comprises:

Calculating the initial running fuel dilution amount during engine operation based on the initial fuel dilution amount at the start of the engine and the starting fuel dilution amount during engine starting;

Calculating an initial fuel evaporation amount when the engine is running according to the initial running fuel dilution amount, the engine coolant temperature, and the engine running time;

Calculating the amount of running fuel dissolved during engine operation according to a preset period according to the intake oil amount and the fuel dilution factor of the engine;

Calculating an operating fuel dilution amount during engine operation according to the initial operating fuel dilution amount, the initial fuel evaporation amount, and the operating fuel dissolution amount;

Based on the operating fuel dilution amount, the engine coolant temperature, and the engine running time, the amount of operating fuel evaporation during engine operation is calculated.

Preferably, the method for obtaining the starting fuel dilution amount during the engine starting process is as follows:

Collect engine coolant temperature;

Obtaining the ethanol content of the ethanol flexible fuel;

Based on the engine coolant temperature and the ethanol content in the ethanol flexible fuel, a look-up of the starting fuel dilution during the engine start is obtained.

Preferably, the method for calculating the fuel dilution factor comprises:

Calculating the initial fuel dilution factor;

Obtaining a first correction factor according to the ethanol content in the ethanol flexible fuel and the engine coolant temperature table;

Obtaining a second correction factor according to the pressure manifold of the intake manifold;

And calculating the fuel dilution factor according to the initial fuel dilution factor, the first correction factor, the second correction factor, and the ethanol oil dilution factor.

Preferably, the calculating the initial fuel dilution factor comprises:

Calculating an excess air ratio on the intake side according to a theoretical air-fuel ratio of the ethanol flexible fuel, an intake air amount, and the intake air amount collected from an engine intake manifold;

Obtaining an exhaust air excess air coefficient according to the intake side excess air coefficient table;

Calculating an exhaust air-fuel ratio according to the exhaust side excess air coefficient and the theoretical air-fuel ratio;

Calculating the exhaust oil amount according to the intake air amount and the exhaust air-fuel ratio;

The initial fuel dilution factor is calculated based on the intake oil amount and the exhaust oil amount.

In another aspect, an ethanol flexible fuel engine fuel injection amount control system is provided, comprising:

a first acquisition module, configured to collect an intake air amount of an engine intake manifold;

The first look-up table module is configured to obtain a target air-fuel ratio according to an engine speed and an engine coolant temperature table;

a first calculation module, configured to calculate a running fuel evaporation amount during engine operation according to a preset period;

a second calculating module, configured to calculate a target fuel injection amount of the engine according to the intake air amount, the target air-fuel ratio, and the running fuel evaporation amount;

And a control module, configured to control the engine to perform fuel injection according to the target fuel injection amount.

Preferably, the first calculation module comprises:

a first calculating unit, configured to calculate an initial running fuel dilution amount when the engine is running according to an initial fuel dilution amount at the time of starting the engine and a starting fuel dilution amount during an engine starting process;

a second calculating unit, configured to calculate an initial fuel evaporation amount when the engine is running according to the initial running fuel dilution amount, the engine coolant temperature, and the engine running time;

a third calculating unit, configured to calculate, according to an intake oil quantity and a fuel dilution factor of the engine, a running fuel dissolved amount during an engine running according to a preset period;

a fourth calculating unit, configured to calculate an operating fuel dilution amount during engine operation according to the initial running fuel dilution amount, the initial fuel evaporation amount, and the running fuel dissolved amount;

And a fifth calculating unit, configured to calculate an operating fuel evaporation amount during engine operation according to the running fuel dilution amount, the engine coolant temperature, and the engine running time.

Preferably, the method further comprises:

a second acquisition module for collecting engine coolant temperature;

Obtaining a module for obtaining an ethanol content in an ethanol flexible fuel;

The second look-up table module obtains the starting fuel dilution amount during the engine starting process according to the engine coolant temperature and the ethanol content in the ethanol flexible fuel.

Preferably, the first calculating module further includes:

a sixth calculating unit for calculating an initial fuel dilution factor;

a first look-up unit, configured to obtain a first correction factor according to an ethanol content in the ethanol flexible fuel and a temperature of the engine coolant;

a second look-up unit for obtaining a second correction factor according to a pressure check table of the intake manifold;

And a seventh calculating unit, configured to calculate the fuel dilution factor according to the initial fuel dilution factor, the first correction factor, the second correction factor, and the ethanol oil dilution factor.

Preferably, the sixth calculating unit comprises:

An eighth calculating unit, configured to calculate an excess air ratio on the intake side according to a theoretical air-fuel ratio of the ethanol flexible fuel, an intake air amount, and the intake air amount collected from an engine intake manifold;

a third look-up unit for obtaining an exhaust air excess air coefficient according to the intake side excess air coefficient table;

a ninth calculating unit, configured to calculate an exhaust air-fuel ratio according to the exhaust side excess air coefficient and the theoretical air-fuel ratio;

a tenth calculating unit, configured to calculate the exhaust oil amount according to the intake air amount and the exhaust air-fuel ratio;

And an eleventh calculating unit, configured to calculate the initial fuel dilution factor according to the intake air amount and the exhaust oil amount.

Method and system for controlling fuel injection amount of ethanol flexible fuel engine provided by embodiments of the present invention According to the intake air volume of the engine intake manifold, the target air-fuel ratio and the running fuel evaporation amount, the target fuel injection amount of the engine is accurately calculated, thereby controlling the engine to perform fuel injection according to the target fuel injection amount. The ethanol flexible fuel engine fuel injection quantity control method and system fully consider the influence of the operating fuel evaporation amount on the air-fuel ratio of the combustible mixed gas during the engine operation, and can accurately calculate the combustible mixed gas according to the target during the engine operation. The air-fuel ratio is the target injection amount required for combustion, thereby controlling the engine to inject fuel according to the target fuel amount, which can effectively improve the fuel utilization efficiency, ensure sufficient combustion, and reduce pollutant emissions.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are merely described in the present invention. Some of the embodiments of the present invention can also be obtained from those of ordinary skill in the art from the drawings.

1 is a flow chart of a method for controlling fuel injection amount of an ethanol flexible fuel engine according to an embodiment of the present invention;

2 is a flow chart of a method for calculating a running fuel evaporation amount during engine operation according to an embodiment of the present invention;

3 is a flowchart of a method for acquiring a starting fuel dilution amount according to an embodiment of the present invention;

4 is a flow chart of a method for calculating a fuel dilution factor according to an embodiment of the present invention;

FIG. 5 is a flowchart of a method for calculating an initial fuel dilution factor according to an embodiment of the present invention; FIG.

6 is a schematic structural diagram of an ethanol fuel injection fuel quantity control system according to an embodiment of the present invention;

Figure 7 is a schematic structural view of the first calculation module of Figure 6;

8 is a schematic structural diagram of another ethanol flexible fuel engine fuel injection amount control system according to an embodiment of the present invention;

FIG. 9 is another schematic structural diagram of the first calculation module of FIG. 6; FIG.

FIG. 10 is a schematic structural view of the sixth calculating unit of FIG. 9.

detailed description

In order to enable those skilled in the art to better understand the solution of the embodiments of the present invention, the following is attached The drawings and embodiments further illustrate the embodiments of the present invention.

As shown in FIG. 1, the method for controlling the fuel injection amount of the ethanol flexible fuel engine according to the embodiment of the present invention comprises the following steps:

Step 101: Collect the intake air amount of the engine intake manifold.

Specifically, the intake of the engine intake air amount may be performed by an intake manifold pressure sensor and an intake manifold temperature sensor provided at the intake manifold.

Step 102: According to the engine speed and the engine coolant temperature, look up the target air-fuel ratio.

Specifically, the engine speed can be collected by a meter or the like, and the engine coolant temperature is collected by a coolant temperature sensor disposed at the water outlet of the engine cooling system. After the engine speed and the engine coolant temperature are collected, those skilled in the art can It is easy to obtain the target air-fuel ratio by looking up the table.

Step 103: Calculate the running fuel evaporation amount during engine operation according to a preset period.

Since the running fuel evaporation amount during engine operation is related to the engine running time, the running fuel evaporation amount can be calculated once every other time, that is, the running fuel evaporation amount during the engine running process is calculated according to the preset period. The preset period can be specifically set according to the control precision requirement, and the shorter the set period is, the more frequently the calculation is, and the control precision is higher. In the embodiment of the present invention, the preset period is preferably set to 125 ms. The specific calculation method of the running fuel evaporation amount will be described in detail through steps 201 to 205.

Step 104: Calculate the target fuel injection amount of the engine according to the intake air amount, the target air-fuel ratio, and the running fuel evaporation amount.

In the embodiment of the present invention, the threshold value (predetermined threshold value) of the running fuel evaporation amount may be preset, and when the running fuel evaporation amount is less than or equal to the preset threshold value, it is considered that the running fuel evaporation amount is small and the air-fuel ratio is affected. Small, negligible, the intake air amount is collected through the above step 101, and after the target air-fuel ratio is obtained in step 102, the fuel injection amount obtained by directly inputting the intake air amount/target air-fuel ratio can be directly used as the target fuel injection amount; When the running fuel evaporation amount is greater than the preset threshold value, it is considered that the running fuel evaporation amount is large, and the air-fuel ratio is greatly affected. According to the formula: target fuel injection amount = intake air amount / target air-fuel ratio - running fuel evaporation amount, according to the above steps The intake air amount collected by 101, the target air-fuel ratio obtained in step 102, and the running fuel evaporation amount calculated in step 103 can calculate the target fuel injection amount of the engine. The preset threshold may be set according to specific needs (such as accuracy requirements), for example, set to 0.2 g/s (g/s).

Step 105: Control the engine to perform fuel injection according to the target fuel injection amount.

After calculating the target fuel injection amount in step 104, the engine is controlled to perform fuel injection according to the target fuel injection amount, which can ensure sufficient combustion, effectively improve fuel utilization efficiency, and reduce pollutant discharge.

The calculation method of the running fuel evaporation amount during the engine operation in step 103 will be described in detail below.

As shown in Figure 2, calculating the amount of operating fuel evaporation during engine operation includes the following steps:

Step 201: Calculate the initial running fuel dilution amount when the engine is running according to the initial fuel dilution amount at the time of engine starting and the starting fuel dilution amount during engine starting.

Since the working process of the engine is mainly divided into two processes: starting and running, wherein the engine starting process refers to a transition process from the start of the engine to the steady state of operation, which usually takes several seconds, in the process, Some of the fuel in the ethanol flexible fuel will dissolve into the oil. When the oil temperature is high, it will evaporate and enter the intake manifold through the positive crankcase ventilation system, causing the air-fuel ratio of the combustible mixture to change. The initial fuel dilution amount is the amount of fuel remaining in the engine oil collected at the moment of engine starting (the amount of fuel dissolved in the engine oil but not evaporated), which may remain in the last time the engine stops running. The amount of fuel in the engine oil is stored in the relevant storage unit, and after the engine is started again, it is collected at the start of the start. Since the engine starting process has a short duration, the amount of fuel evaporation during the starting process can be neglected. Therefore, after the engine completes the start, after entering the normal operation, the initial running fuel dilution amount when the engine starts running is equal to the initial fuel dilution amount at the engine starting. And the sum of the starting fuel dilution during engine starting.

As shown in FIG. 3, the method for obtaining the starting fuel dilution amount during engine starting includes the following steps:

Step 301: Collecting a coolant temperature of the engine;

Step 302: Obtain an ethanol content in the ethanol flexible fuel;

Step 303: According to the coolant temperature of the engine and the ethanol content in the ethanol flexible fuel, look up the starting fuel dilution amount during the engine starting process.

Specifically, a coolant temperature sensor may be disposed on the water outlet of the engine cooling system for collecting the temperature of the engine coolant, and the ethanol content is easily obtained according to the ratio of ethanol to gasoline in the flexible fuel used. Wherein, the correspondence relationship between the coolant temperature and the ethanol content in the ethanol flexible fuel and the starting fuel dilution amount is previously constructed according to experience or calculation, and those skilled in the art It is easy for the member to obtain the correspondence table, and the table can be manually checked, or it can be stored in the relevant storage unit in advance, and is called when needed by the setting of the computer program. After collecting the coolant temperature of the engine and obtaining the ethanol content in the ethanol flexible fuel, the meter reading program can be automatically activated to obtain the starting fuel dilution amount during the engine starting process by looking up the table. For other aspects of the present invention, the related content of the table, the construction, the acquisition, the invocation, and the like of the respective tables may be referred to the related descriptions herein.

Step 202: Calculate the initial fuel evaporation amount when the engine is running according to the initial running fuel dilution amount, the engine coolant temperature, and the engine running time.

After calculating the initial running fuel dilution amount in step 201, according to the coolant temperature collected by the coolant temperature sensor, the initial fuel evaporation rate can be obtained by looking up the table, and after collecting the engine running time, according to the formula: initial fuel evaporation amount = initial Fuel evaporation rate * engine running time, can calculate the initial fuel evaporation when the engine is running.

Step 203: Calculate the running fuel dissolved amount during the engine running according to the preset period according to the intake air amount of the engine and the fuel dilution factor.

During the operation of the engine, the fuel dissolved in the oil will evaporate, thereby affecting the air-fuel ratio of the combustible mixture. In order to ensure sufficient combustion of the combustible mixture, the air-fuel ratio of the combustible mixture is adjusted by controlling the fuel quantity of the engine to make the combustible The air-fuel ratio of the mixed gas is substantially close to the target air-fuel ratio set in advance. We refer to the engine fuel amount corresponding to the target air-fuel ratio as the intake air amount (also referred to as the target fuel amount), which is known to those skilled in the art. In the case of the air-fuel ratio, it is easy to calculate the amount of intake air.

The fuel dilution factor is a key parameter that characterizes the oil's ability to dissolve fuel, which can be affected by a variety of factors. For example, the initial fuel dilution factor, the ethanol content of the ethanol flexible fuel, the engine coolant temperature, and the intake manifold pressure all have an effect on the fuel dilution factor.

After calculating the intake oil amount and the initial fuel evaporation amount according to the above steps, the operating fuel dissolving amount can be calculated according to the formula: running fuel dissolving amount = (intake oil amount - initial fuel evaporating amount) * fuel dilution factor.

Step 204: Calculate the running fuel dilution amount according to the initial running fuel dilution amount, the initial fuel evaporation amount, and the running fuel dissolution amount.

After obtaining the initial running fuel dilution amount and the initial fuel evaporation amount by step 203, according to the formula: running fuel dilution amount = running fuel dissolved amount - initial fuel evaporation amount + initial running fuel dilution amount, Calculate the running fuel dilution amount.

Step 205: Calculate the running fuel evaporation amount during engine operation according to the running fuel dilution amount, the engine coolant temperature, and the engine running time.

Since the fuel evaporation rate changes with the engine coolant temperature during engine operation, it is necessary to collect the engine coolant temperature according to the preset period, and check the table to obtain the operating fuel evaporation rate at different operating times of the engine. According to the formula: operating fuel evaporation Quantity = operating fuel evaporation rate * engine running time, you can find the amount of running fuel evaporation during engine operation.

As shown in FIG. 4, it is a flowchart of a method for calculating a fuel dilution factor in step 203, which specifically includes the following steps:

Step 401: Calculate an initial fuel dilution factor.

The above initial fuel dilution factor is a parameter characterizing the initial value of the fuel dissolved in the oil, specifically, the initial fuel dilution factor = (intake oil amount - exhaust oil amount) / intake oil amount, wherein the intake oil amount It is easy to calculate based on the target air-fuel ratio. According to the "wet wall effect", a part of the fuel sprayed from the engine will adhere to the intake pipe and will not participate in the actual combustion, resulting in unequal amount of exhaust oil and intake oil. Therefore, it is necessary to accurately calculate the "wet wall". The initial fuel dilution factor in the case of an effect.

As shown in Figure 5, calculating the initial fuel dilution factor includes the following steps:

Step 501: Calculate the excess air ratio on the intake side according to the theoretical air-fuel ratio of the ethanol flexible fuel, the amount of intake air, and the amount of intake air collected from the intake manifold of the engine.

The theoretical air-fuel ratio refers to the air-fuel ratio between air and fuel (ethanol and fuel) when the combustible mixture is completely burned. When the model specification of the flexible fuel used is specified, the theoretical air-fuel ratio is easily calculated.

Through the above steps, the theoretical air-fuel ratio, the intake air amount, and the pressure and temperature data detected by the intake manifold pressure sensor and the intake manifold temperature sensor disposed at the intake manifold are obtained, and the intake air amount is obtained. According to the formula: excess air ratio on the intake side = (intake amount / intake oil amount) / theoretical air-fuel ratio, the excess air ratio on the intake side is calculated.

Step 502: Obtain an exhaust air excess air coefficient according to an intake air excess air coefficient table.

After calculating the excess air ratio on the intake side by the step 501, the person skilled in the art can easily obtain the excess air coefficient on the exhaust side by means of a look-up table, wherein the correspondence relationship between the excess air ratio on the intake side and the excess air coefficient on the exhaust side is obtained. For the prior construction by experiment, the person skilled in the art Easy to get the table.

Step 503: Calculate the air-fuel ratio of the exhaust gas according to the exhaust air excess air coefficient and the theoretical air-fuel ratio.

After the exhaust air excess air coefficient and the stoichiometric air-fuel ratio are calculated by the above steps, the exhaust air-fuel ratio is easily calculated according to the formula: exhaust air-fuel ratio = exhaust-side excess air ratio * theoretical air-fuel ratio.

Step 504: Calculate the exhaust oil amount according to the intake air amount and the exhaust air-fuel ratio.

When the intake air amount is obtained by step 501 and the exhaust air-fuel ratio is calculated by step 503, since the exhaust gas amount is equal to the intake air amount, according to the formula: the exhaust gas amount = the exhaust gas amount / the exhaust air-fuel ratio, it is easy Calculate the amount of exhaust oil.

Step 505: Calculate an initial fuel dilution factor according to the intake oil amount and the exhaust oil amount.

When the intake oil amount and the exhaust oil amount are known, the initial fuel dilution factor can be calculated according to the formula: initial fuel dilution factor = (intake oil amount - exhaust oil amount) / intake oil amount.

After calculating the initial fuel dilution factor through the above steps, since the ethanol content in the ethanol flexible fuel, the engine coolant temperature and the intake manifold pressure will affect the fuel dilution factor, the initial fuel dilution factor needs to be corrected to calculate Get the fuel dilution factor.

Among them, the person skilled in the art can easily obtain the corresponding fuel dilution factor correction relationship correspondence table when calculating the initial fuel dilution factor, thereby obtaining the correction factor by looking up the table. Specifically, the first correction factor and the second correction factor may be obtained by looking up the table through

steps

402 and 403, respectively:

Step 402: Obtain a first correction factor according to the ethanol content in the ethanol flexible fuel and the temperature of the engine coolant.

Step 403: Obtain a second correction factor according to the pressure manifold of the intake manifold.

The foregoing step 402 and step 403 are not limited to the foregoing execution sequence. Step 403 may be performed first, and then step 402 may be performed. Step 402 and step 403 may be performed at the same time, which is not specifically limited in this embodiment of the present invention.

Step 404: Calculate a fuel dilution factor according to an initial fuel dilution factor, a first correction factor, a second correction factor, and an ethanol oil dilution factor.

Since the ethanol oil dilution factor also affects the fuel dilution factor, it is also necessary to obtain an ethanol oil dilution factor. Among them, the value of the ethanol oil dilution factor is a constant value, for example, 0.5, which is easily obtained by a person skilled in the art. After obtaining the initial fuel dilution factor, the first correction factor, the second correction factor, and the ethanol oil dilution factor by the above steps, the fuel thinning can be calculated. Release factor.

The method for controlling the fuel injection amount of the ethanol flexible fuel engine provided by the embodiment of the invention can accurately calculate the target fuel injection amount of the engine according to the intake air amount of the engine intake manifold, the target air-fuel ratio and the running fuel evaporation amount, thereby controlling the engine according to the method. The target injection amount is injected. The ethanol flexible fuel engine fuel injection quantity control method and system fully consider the influence of the operating fuel evaporation amount on the air-fuel ratio of the combustible mixed gas during the engine operation, and can accurately calculate the combustible mixed gas according to the target during the engine operation. The air-fuel ratio is the target injection amount required for combustion, thereby controlling the engine to inject fuel according to the target fuel amount, which can effectively improve the fuel utilization efficiency, ensure sufficient combustion, and reduce pollutant emissions.

Correspondingly, an embodiment of the present invention further provides an ethanol fuel injection fuel quantity control system, as shown in FIG. 6, comprising:

a first collecting module 601, configured to collect an intake air amount of an engine intake manifold;

The first look-up table module 602 is configured to obtain a target air-fuel ratio according to an engine speed and an engine coolant temperature table;

a first calculating module 603, configured to calculate, according to a preset period, an operating fuel evaporation amount during an engine running process;

a second calculating module 604, configured to calculate a target fuel injection amount of the engine according to the intake air amount, the target air-fuel ratio, and the running fuel evaporation amount;

The control module 605 is configured to control the engine to perform fuel injection according to the target fuel injection amount.

As shown in FIG. 7, the first calculation module 603 includes:

a first calculating unit 701, configured to calculate an initial running fuel dilution amount when the engine is running according to an initial fuel dilution amount at the time of starting the engine and a starting fuel dilution amount during an engine starting process;

a second calculating unit 702, configured to calculate an initial fuel evaporation amount when the engine is running according to the initial running fuel dilution amount, the engine coolant temperature, and the engine running time;

a third calculating unit 703, configured to calculate, according to an intake air amount of the engine and a fuel dilution factor, a running fuel dissolved amount during engine operation according to a preset period;

a fourth calculating unit 704, configured to calculate an operating fuel dilution amount during engine operation according to the initial running fuel dilution amount, the initial fuel evaporation amount, and the running fuel dissolved amount;

The fifth calculating unit 705 is configured to calculate the running fuel evaporation amount during the engine running according to the running fuel dilution amount, the engine coolant temperature, and the engine running time.

As shown in Fig. 8, the ethanol flexible fuel engine fuel injection amount control system further includes:

a second collecting module 801, configured to collect an engine coolant temperature;

An obtaining module 802, configured to obtain an ethanol content in the ethanol flexible fuel;

The second look-up table module 803 looks up the starting fuel dilution amount during engine starting according to the engine coolant temperature and the ethanol content in the ethanol flexible fuel.

As shown in FIG. 9, the first calculating module 603 further includes:

a sixth calculating unit 706, configured to calculate an initial fuel dilution factor;

The first look-up table unit 707 is configured to obtain a first correction factor according to an ethanol content in the ethanol flexible fuel and a temperature of the engine coolant;

a second lookup unit 708, configured to obtain a second correction factor according to a pressure check table of the intake manifold;

The seventh calculating unit 709 is configured to calculate a fuel dilution factor according to the initial fuel dilution factor, the first correction factor, the second correction factor, and the ethanol oil dilution factor.

As shown in FIG. 10, the sixth calculating unit 706 includes:

An eighth calculating unit 901, configured to calculate an excess air coefficient on the intake side according to a theoretical air-fuel ratio of the ethanol flexible fuel, an intake air amount, and an intake air amount collected from an engine intake manifold;

a third look-up table unit 902, configured to obtain an exhaust-side excess air coefficient according to an intake air excess air coefficient look-up table;

a ninth calculating unit 903, configured to calculate an exhaust air-fuel ratio according to an exhaust air excess air coefficient and a theoretical air-fuel ratio;

a tenth calculating unit 904, configured to calculate an exhaust oil amount according to the intake air amount and the exhaust air-fuel ratio;

The eleventh calculating unit 905 is configured to calculate an initial fuel dilution factor according to the intake oil amount and the exhaust oil amount.

The ethanol flexible fuel engine fuel injection amount control system provided by the embodiment of the invention can accurately calculate the target fuel injection amount of the engine according to the intake air amount of the engine intake manifold, the target air-fuel ratio and the running fuel evaporation amount, thereby controlling the engine according to the The target injection amount is injected. The ethanol flexible fuel engine fuel injection quantity control method and system fully consider the influence of the operating fuel evaporation amount on the air-fuel ratio of the combustible mixed gas during the engine operation, and can accurately calculate the combustible mixed gas according to the target during the engine operation. The air-fuel ratio is the target injection amount required for combustion, thereby controlling the engine to inject fuel according to the target fuel amount, which can effectively improve the fuel utilization efficiency, ensure sufficient combustion, and reduce pollutant emissions.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalents, improvements, etc., which are within the spirit and scope of the present invention, should be included in the protection of the present invention. Within the scope.

Claims

A method for controlling fuel injection quantity of an ethanol flexible fuel engine, comprising:

Collecting the intake air amount of the engine intake manifold;

According to the engine speed and the engine coolant temperature, look up the table to get the target air-fuel ratio;

Calculate the amount of running fuel evaporation during engine operation according to a preset period;

Calculating a target fuel injection amount of the engine according to the intake air amount, the target air-fuel ratio, and the operating fuel evaporation amount;

The engine is controlled to inject oil in accordance with the target injection amount.
The fuel injection quantity control method for an ethanol flexible fuel engine according to claim 1, wherein the calculating the amount of running fuel evaporation during engine operation according to a preset period comprises:

Calculating the initial running fuel dilution amount during engine operation based on the initial fuel dilution amount at the start of the engine and the starting fuel dilution amount during engine starting;

Calculating an initial fuel evaporation amount when the engine is running according to the initial running fuel dilution amount, the engine coolant temperature, and the engine running time;

Calculating the amount of running fuel dissolved during engine operation according to a preset period according to the intake oil amount and the fuel dilution factor of the engine;

Calculating an operating fuel dilution amount during engine operation according to the initial operating fuel dilution amount, the initial fuel evaporation amount, and the operating fuel dissolution amount;

Based on the operating fuel dilution amount, the engine coolant temperature, and the engine running time, the amount of operating fuel evaporation during engine operation is calculated.
The ethanol flexible fuel engine fuel injection amount control method according to claim 2, wherein the method for obtaining the starting fuel dilution amount during the engine starting process is as follows:

Collect engine coolant temperature;

Obtaining the ethanol content of the ethanol flexible fuel;

Based on the engine coolant temperature and the ethanol content in the ethanol flexible fuel, a look-up of the starting fuel dilution during the engine start is obtained.
The fuel injection quantity control method for an ethanol flexible fuel engine according to claim 3, wherein the calculation method of the fuel dilution factor comprises:

Calculating the initial fuel dilution factor;

Obtaining a first correction factor according to the ethanol content in the ethanol flexible fuel and the engine coolant temperature table;

Obtaining a second correction factor according to the pressure manifold of the intake manifold;

And calculating the fuel dilution factor according to the initial fuel dilution factor, the first correction factor, the second correction factor, and the ethanol oil dilution factor.
The method for controlling fuel injection amount of an ethanol flexible fuel engine according to claim 4, wherein said calculating an initial fuel dilution factor comprises:

Calculating an excess air ratio on the intake side according to a theoretical air-fuel ratio of the ethanol flexible fuel, an intake air amount, and the intake air amount collected from an engine intake manifold;

Obtaining an exhaust air excess air coefficient according to the intake side excess air coefficient table;

Calculating an exhaust air-fuel ratio according to the exhaust side excess air coefficient and the theoretical air-fuel ratio;

Calculating the exhaust oil amount according to the intake air amount and the exhaust air-fuel ratio;

The initial fuel dilution factor is calculated based on the intake oil amount and the exhaust oil amount.
An ethanol flexible fuel engine fuel injection quantity control system, comprising:

a first acquisition module, configured to collect an intake air amount of an engine intake manifold;

The first look-up table module is configured to obtain a target air-fuel ratio according to an engine speed and an engine coolant temperature table;

a first calculation module, configured to calculate a running fuel evaporation amount during engine operation according to a preset period;

a second calculating module, configured to calculate a target fuel injection amount of the engine according to the intake air amount, the target air-fuel ratio, and the running fuel evaporation amount;

And a control module, configured to control the engine to perform fuel injection according to the target fuel injection amount.
The fuel injection quantity control system for an ethanol flexible fuel engine according to claim 6, wherein the first calculation module comprises:

a first calculating unit, configured to calculate an initial running fuel dilution amount when the engine is running according to an initial fuel dilution amount at the time of starting the engine and a starting fuel dilution amount during an engine starting process;

a second calculating unit, configured to calculate an initial fuel evaporation amount when the engine is running according to the initial running fuel dilution amount, the engine coolant temperature, and the engine running time;

a third calculating unit, configured to calculate, according to an intake oil quantity and a fuel dilution factor of the engine, a running fuel dissolved amount during an engine running according to a preset period;

a fourth calculating unit, configured to calculate an operating fuel dilution amount during engine operation according to the initial running fuel dilution amount, the initial fuel evaporation amount, and the running fuel dissolved amount;

And a fifth calculating unit, configured to calculate an operating fuel evaporation amount during engine operation according to the running fuel dilution amount, the engine coolant temperature, and the engine running time.
The fuel injection quantity control system for an ethanol flexible fuel engine according to claim 7, further comprising:

a second acquisition module for collecting engine coolant temperature;

Obtaining a module for obtaining an ethanol content in an ethanol flexible fuel;

The second look-up table module obtains the starting fuel dilution amount during the engine starting process according to the engine coolant temperature and the ethanol content in the ethanol flexible fuel.
The fuel injection control system for an ethanol flexible fuel engine according to claim 8, wherein the first calculation module further comprises:

a sixth calculating unit for calculating an initial fuel dilution factor;

a first look-up unit, configured to obtain a first correction factor according to an ethanol content in the ethanol flexible fuel and a temperature of the engine coolant;

a second look-up unit for obtaining a second correction factor according to a pressure check table of the intake manifold;

And a seventh calculating unit, configured to calculate the fuel dilution factor according to the initial fuel dilution factor, the first correction factor, the second correction factor, and the ethanol oil dilution factor.
The ethanol flexible fuel engine fuel injection amount control system according to claim 9, wherein the sixth calculating unit comprises:

An eighth calculating unit, configured to calculate an excess air ratio on the intake side according to a theoretical air-fuel ratio of the ethanol flexible fuel, an intake air amount, and the intake air amount collected from an engine intake manifold;

a third look-up unit for obtaining an exhaust air excess air coefficient according to the intake side excess air coefficient table;

a ninth calculating unit, configured to calculate an exhaust air-fuel ratio according to the exhaust side excess air coefficient and the theoretical air-fuel ratio;

a tenth calculating unit, configured to calculate the exhaust oil amount according to the intake air amount and the exhaust air-fuel ratio;

And an eleventh calculating unit, configured to calculate the initial fuel dilution factor according to the intake air amount and the exhaust oil amount.