阅读说明：本技术 发动机系统及发动机进气异常的检测方法 (Engine system and method for detecting intake abnormality of engine ) 是由 潘俊 许建昌 彭智华 刘思 于 2018-08-23 设计创作，主要内容包括：本发明提供了一种发动机系统及发动机进气异常的检测方法,曲轴箱的通风管路与气缸的进气管路连通,能实现对曲轴箱内窜气的通风。利用发动机系统的节气门开启的程度、第一压力和第一温度计算出第一进气流量；利用第二压力、第二温度、曲轴转速和气缸排量计算出第二进气流量；比较第一进气流量和第二进气流量的值；若第一进气流量小于第二进气流量并且第一进气流量与第二进气流量的差值达到预设值时,判断所述通风管路已经断开。在本发明提供的发动机系统及发动机进气异常的检测方法中,能判断通风管路是否断开从而防止窜气泄漏到大气中造成环境污染。(The invention provides an engine system and a method for detecting abnormal air intake of the engine. Calculating a first intake air flow rate using a degree of throttle opening of an engine system, a first pressure, and a first temperature; calculating a second intake air flow by using the second pressure, the second temperature, the crankshaft speed and the cylinder displacement; comparing values of the first intake air flow rate and the second intake air flow rate; and if the first air inflow is smaller than the second air inflow and the difference value between the first air inflow and the second air inflow reaches a preset value, judging that the ventilation pipeline is disconnected. In the engine system and the method for detecting the intake abnormity of the engine, provided by the invention, whether the ventilation pipeline is disconnected or not can be judged, so that the blow-by gas is prevented from leaking into the atmosphere to cause environmental pollution.)

1. An engine system, characterized in that the engine system comprises: the air inlet pipeline, the throttle valve, the air cylinder, the crankshaft, the crankcase and the ventilation pipeline are sequentially connected through the air inlet pipeline, the air cylinder is positioned on the crankcase, the crankshaft is positioned in the crankcase, and the crankcase is communicated with the ventilation pipeline;

the ventilation pipeline is divided into a first ventilation pipeline and a second ventilation pipeline, the first ventilation pipeline is connected to an air inlet pipeline between the air cylinder and the throttle valve, the second ventilation pipeline is connected to an air inlet pipeline in front of the throttle valve, and the first ventilation pipeline is communicated with the second ventilation pipeline;

when the throttle valve is opened, gas can flow in the air inlet pipeline, and the gas flow rate of the air inlet pipeline is positively correlated with the opening degree of the throttle valve;

air reaches the cylinder through the throttle valve and the air inlet pipeline, the cylinder burns the air to enable the crankshaft to rotate, the air which is not completely burnt in the cylinder can enter the crankcase to form blowby gas, the blowby gas enters the air inlet pipeline through the first ventilation pipeline and the second ventilation pipeline from the crankcase respectively, and the blowby gas and the air are mixed and then are combusted again for use.

2. The engine system of claim 1, further comprising an air filter on the intake conduit before the throttle valve, the air filter for filtering air entering the intake conduit, a supercharger, and a intercooler; the supercharger is positioned on an air inlet pipeline between the air filter and the throttle valve, and is used for increasing air pressure so as to increase the air inflow; the intercooler is positioned between the supercharger and the cylinder and is connected with the supercharger and the cylinder through the air inlet pipeline, and is used for reducing the temperature of the air passing through the supercharger; the second ventilation pipeline is connected to an air inlet pipeline between the air filter and the supercharger.

3. The engine system of claim 2, further comprising a first sensor selected from a pressure temperature sensor located in the intake conduit between the intercooler and the throttle valve, the first sensor configured to sense a pressure and a temperature of gas in the intake conduit, the pressure of gas sensed by the first sensor being a first pressure and the temperature of gas sensed by the first sensor being a first temperature.

4. The engine system of claim 3, further comprising a second sensor located in an intake conduit between the throttle valve and the cylinder, the second sensor configured to sense a temperature of gas in the intake conduit, the temperature of gas sensed by the second sensor being a second temperature.

5. The engine system of claim 4, further comprising a third sensor located in an intake conduit between the throttle valve and the cylinder, the third sensor configured to sense a pressure of gas in the intake conduit, the pressure of gas sensed by the third sensor being a second pressure.

6. A method of detecting an intake abnormality of an engine, characterized by comprising:

calculating a first intake air flow rate using the degree of throttle opening, the first pressure, and the first temperature;

calculating a second intake air flow using the second pressure, the second temperature, a crankshaft speed, and a cylinder displacement;

comparing values of the first intake air flow rate and the second intake air flow rate;

and if the first air inflow is smaller than the second air inflow and the difference value between the first air inflow and the second air inflow is larger than or equal to a preset value, judging that the ventilation pipeline is disconnected.

7. The engine intake abnormality detection method according to claim 6, characterized in that the first intake air flow rate M is obtained by the following formula_S(DK)：

Wherein A is the projection area of the throttle opening in the direction vertical to the air inlet pipeline, and P is₀Is a first pressure, M is the molar mass of air, k is the adiabatic index of air, R is the gas constant, T₀Is the first temperature and Y is the gas expansion factor.

8. The engine intake air abnormality detection method according to claim 7, characterized in that when the ratio P of the second pressure to the first pressure is high_S/P₀When it is less than 0.5283, the first intake air flow rate is obtained where Y is 1.

9. The engine intake air abnormality detection method according to claim 8, characterized in that when the ratio P of the second pressure to the first pressure is high_S/P₀Above 0.5283, Y in the equation for obtaining the first intake air flow rate is calculated by the equation:

10. the engine intake abnormality detection method according to claim 6, characterized in that the second intake air flow rate M is obtained by the following formula_S(P)：

Wherein: n is crankshaft speed, M is air molar mass, P_SAt a second pressure, V is the displacement of the cylinder, R is the gas constant, T_SIs the second temperature.

11. The method of detecting intake abnormality of an engine according to claim 6, wherein the preset value is a value of 10kg/h to 20 kg/h.

12. The engine intake abnormality detection method according to claim 11, characterized in that it is determined that the ventilation pipe is not disconnected when the first intake air flow rate is equal to the second intake air flow rate or a difference between the first intake air flow rate and the second intake air flow rate is smaller than the preset value.

Technical Field

The invention relates to the field of automobile engines, in particular to an engine system and a method for detecting intake abnormity of an engine.

Background

When the engine works, air can enter the cylinder through the air inlet pipeline to perform combustion work, unburned gas in the cylinder can enter the crankcase through a gap between the piston and the cylinder sleeve in the process, and the gas entering the crankcase can be leaked into the atmosphere to cause environmental pollution. Emission regulations require that automotive manufacturers must monitor crankcase ventilation system vent line disconnection failures to prevent crankcase blow-by gas leakage to the atmosphere due to the vent line disconnection.

Disclosure of Invention

The invention aims to provide an engine ventilation system and a method for judging disconnection of a ventilation pipeline, which can ventilate blowby gas in a crankcase, can detect whether the ventilation pipeline is disconnected or not, and prevent the blowby gas from leaking into the atmosphere to cause pollution.

In order to achieve the above object, the present invention provides an engine system comprising: the air inlet pipeline, the throttle valve, the air cylinder, the crankshaft, the crankcase and the ventilation pipeline are sequentially connected through the air inlet pipeline, the air cylinder is positioned on the crankcase, the crankshaft is positioned in the crankcase, and the crankcase is communicated with the ventilation pipeline;

the ventilation pipeline is divided into a first ventilation pipeline and a second ventilation pipeline, the first ventilation pipeline is connected to an air inlet pipeline between the air cylinder and the throttle valve, the second ventilation pipeline is connected to an air inlet pipeline positioned in front of the throttle valve, and the first ventilation pipeline is communicated with the second ventilation pipeline;

when the throttle valve is opened, gas can flow in the air inlet pipeline, and the gas flow rate of the air inlet pipeline is positively correlated with the opening degree of the throttle valve;

air reaches the cylinder through the throttle valve and the air inlet pipeline, the cylinder burns the air to enable the crankshaft to rotate, the air which is not completely burnt in the cylinder can enter the crankcase to form blowby gas, the blowby gas enters the air inlet pipeline through the first ventilation pipeline and the second ventilation pipeline from the crankcase respectively, and the blowby gas and the air are mixed and then are combusted again for use.

Optionally, in the engine system, the engine system further includes an air filter, a supercharger and a intercooler, the air filter is located on the air intake pipeline before the throttle valve, and the air filter is used for filtering air entering the air intake pipeline; the supercharger is positioned on an air inlet pipeline between the air filter and the throttle valve, and is used for increasing air pressure so as to increase the air inflow; the intercooler is positioned between the supercharger and the cylinder and is connected with the supercharger and the cylinder through the air inlet pipeline, and the intercooler is used for reducing the temperature of air passing through the supercharger; the second ventilation pipeline is connected to an air inlet pipeline between the air filter and the supercharger.

Optionally, in the engine system, the engine system further includes a first sensor, the first sensor is selected from a pressure and temperature sensor, the first sensor is located on an intake pipe between the intercooler and the throttle valve, the first sensor is configured to sense a gas pressure and a gas temperature in the intake pipe, the gas pressure sensed by the first sensor is a first pressure, and the gas temperature sensed by the first sensor is a first temperature.

Optionally, in the engine system, the engine system further includes a second sensor, the second sensor is located on an intake pipe between the throttle valve and the cylinder, the second sensor is configured to sense a temperature of gas in the intake pipe, and the temperature of gas sensed by the second sensor is a second temperature.

Optionally, in the engine system, the engine system further includes a third sensor, the third sensor is located in an intake pipe between the throttle valve and the cylinder, the third sensor is configured to sense a gas pressure in the intake pipe, and the gas pressure sensed by the third sensor is a second pressure.

Correspondingly, the invention also provides a method for detecting the intake abnormity of the engine, which comprises the following steps:

calculating a first intake air flow rate using the degree of throttle opening, the first pressure, and the first temperature;

calculating a second intake air flow using the second pressure, the second temperature, a crankshaft speed, and a cylinder displacement;

comparing values of the first intake air flow rate and the second intake air flow rate;

and if the first air inflow is smaller than the second air inflow and the difference value between the first air inflow and the second air inflow is larger than or equal to a preset value, judging that the ventilation pipeline is disconnected.

Alternatively, in the method for detecting intake abnormality of an engine, the first intake air flow rate M is obtained by the following formula_S(DK)：

Wherein A is the projection area of the throttle opening in the direction vertical to the air inlet pipeline, and P is₀Is a first pressure, M is the molar mass of air, k is the adiabatic index of air, R is the gas constant, T₀Is the first temperature and Y is the gas expansion factor.

Optionally, in the method for detecting intake abnormality of engine, when the ratio P of the second pressure to the first pressure is higher than the second pressure_S/P₀When it is less than 0.5283, the first intake air flow rate is obtained where Y is 1.

Optionally, in the method for detecting intake abnormality of engine, when the ratio P of the second pressure to the first pressure is higher than the second pressure_S/P₀Above 0.5283, Y in the equation for obtaining the first intake air flow rate is calculated by the equation:

alternatively, in the method for detecting intake abnormality of an engine, the second intake air flow rate M is obtained by the following formula_S(P)：

Wherein: n is crankshaft speed, M is air molar mass, P_SAt a second pressure, V is the displacement of the cylinder, R is the gas constant, T_SIs the second temperature.

Optionally, in the method for detecting intake abnormality of an engine, the preset value is 10kg/h to 20 kg/h.

Optionally, in the method for detecting intake abnormality of an engine, when the first intake air flow rate is equal to the second intake air flow rate or a difference between the first intake air flow rate and the second intake air flow rate is smaller than the preset value, it is determined that the ventilation pipe is not disconnected.

In the engine system and the method for detecting the intake abnormity of the engine, the ventilation pipeline of the crankcase is communicated with the intake pipeline of the cylinder, so that the ventilation of the crankcase can be realized, and whether the pipeline is disconnected or not can be conveniently detected; the invention also provides a detection method for the intake abnormity of the engine, which can detect whether the ventilation pipeline is disconnected or not and prevent the blow-by gas of the crankcase from entering the atmosphere to cause pollution.

Drawings

FIG. 1 is a schematic structural view of an engine ventilation system according to an embodiment of the present invention;

FIG. 2 is a flow chart of a method for determining the disconnection of a ventilation line according to an embodiment of the present invention;

FIG. 3 is a graph comparing a first intake air flow rate to a second intake air flow rate with a vent line of an embodiment of the present invention disconnected;

wherein: 110-air filter, 120-air inlet line, 130-supercharger, 140-intercooler, 150-cylinder, 160-crankcase, 170-ventilation line, 171-first ventilation line, 172-second ventilation line, 180-throttle, 191-first sensor, 192-second sensor, 193-third sensor, 194-check valve, 195-control valve, first air inlet flow curve when 1-ventilation line is disconnected, and second air inlet flow curve when 2-ventilation line is disconnected.

Detailed Description

The following describes in more detail embodiments of the present invention with reference to the schematic drawings. Advantages and features of the present invention will become apparent from the following description and claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Referring to fig. 1, the present disclosure provides an engine system including: the air filter 110, the air inlet pipeline 120, the supercharger 130, the throttle valve 180, the cylinder 150, the crankshaft (not shown in the figure), the crankcase 160 and the ventilation pipeline 170, wherein the air filter 110, the supercharger 130, the throttle valve 180 and the cylinder 150 are connected in sequence through the air inlet pipeline 120, the cylinder 150 is positioned on the crankcase 160, the crankshaft is positioned in the crankcase 160, and the crankcase 160 is communicated with the ventilation pipeline 170;

the ventilation line 170 is divided into a first ventilation line 171 and a second ventilation line 172, the first ventilation line 171 is connected to the intake line 120 between the cylinder 150 and the throttle valve 180, the second ventilation line 172 is connected to the intake line 120 between the air cleaner 110 and the supercharger 130, and the first ventilation line 171 and the second ventilation line 172 are communicated;

the air filter 110 is used for filtering air;

the supercharger 130 is used to increase air pressure so as to increase the intake air amount;

when the throttle valve 180 is open, gas can flow in the intake pipe 120, and the gas flow rate of the intake pipe 120 is positively correlated with the degree to which the throttle valve 180 is open;

air passes through the air filter 110, the supercharger 130, the throttle valve 180 and the air intake pipe 120 to the cylinder 150, the cylinder 150 burns the air to rotate a crankshaft, the air which is not completely burnt in the cylinder 150 enters the crankcase 160 to form blow-by gas, the blow-by gas enters the air intake pipe 120 from the crankcase 160 through the first ventilation pipe 171 and the second ventilation pipe 172 respectively, and the blow-by gas and the air are mixed and then combusted again for use.

In the present embodiment, when the engine is operating in a low load condition (e.g., the engine load is less than 40%), gas in the crankcase 160 is drawn into the intake conduit 120 through the first ventilation conduit 171; when the engine is operated in a high-load condition (for example, the load of the engine is greater than or equal to 40%), the gas in the crankcase 160 is sucked into the air inlet pipeline 120 through the second ventilation pipeline 172, and finally the blow-by gas enters the cylinder for reuse, so that the atmosphere pollution caused by the inflow of the atmosphere is avoided.

In this embodiment, the first ventilation pipeline 113 and the second ventilation pipeline 112 are respectively connected to the air intake pipeline 120 through a one-way valve 194, and the one-way valve 194 can prevent air in the air intake pipeline 120 from entering the first ventilation pipeline 113 and the second ventilation pipeline 112. The check valve 194 provided at the junction of the first ventilation pipe 171 and the intake pipe 120 may be provided at any position in the first ventilation pipe 171. The one-way valve 194 provided at the junction of the second vent line 172 and the air intake line 120 may also be provided anywhere within the second vent line 172.

In this embodiment, a control valve 195 is further disposed at a connection between the ventilation pipeline and the crankcase 160, and the control valve 195 may control a flow rate of the blow-by gas.

Preferably, the engine system further comprises an intercooler 140, the intercooler 140 is located between the supercharger 130 and the cylinder 150 and connected with the supercharger 130 and the cylinder 150 through the air inlet pipeline 120, and the intercooler 140 is used for reducing the temperature of the air after passing through the supercharger.

Preferably, the engine system further comprises a first sensor 191, the first sensor 191 is selected from a pressure and temperature sensor, the first sensor 191 is located on the air intake pipe 120 between the intercooler 140 and the throttle valve 180, the first sensor 191 is used for sensing the air pressure and the air temperature in the air intake pipe 120, the air pressure sensed by the first sensor is a first pressure, and the air temperature sensed by the first sensor is a first temperature. The intake air flow rate may be calculated from the gas pressure and the gas temperature on the intake line 120 between the intercooler 140 and the throttle valve 180.

Preferably, the engine system further comprises a second sensor 192, the second sensor 192 is located on the air intake conduit 120 between the throttle valve 180 and the cylinder 150, the second sensor 192 is used for sensing the temperature of the air in the air intake conduit 120, and the temperature of the air sensed by the second sensor 192 is a second temperature. The second sensor 192 may be a conventional temperature sensor and the temperature of the gas in the intake line 120 between the throttle valve 180 and the cylinder 150 may be measured to calculate the intake air flow rate.

Preferably, the engine system further comprises a third sensor 193, the third sensor 193 is located on the intake pipe 120 between the throttle valve 180 and the cylinder 150, the third sensor 193 is used for sensing the gas pressure in the intake pipe 120, and the gas pressure sensed by the third sensor 193 is a second pressure. The third sensor 193 may be a conventional pressure sensor, and the intake air flow rate may be calculated by measuring the gas pressure in the intake line 120 between the throttle valve 180 and the cylinder 150.

Correspondingly, the invention also provides a method for detecting the intake abnormity of the engine, which comprises the following steps:

s11: calculating a first intake air flow rate using the degree to which the throttle valve 180 is opened, the first pressure, and the first temperature;

s12: calculating a second intake air flow using the second pressure, the second temperature, a crankshaft speed, and a displacement of the cylinder 150;

s13: comparing values of the first intake air flow rate and the second intake air flow rate;

s14: if the first intake air flow rate is less than the second intake air flow rate and the difference between the first intake air flow rate and the second intake air flow rate is greater than or equal to a preset value, it is determined that the ventilation pipe 170 is disconnected.

In the present embodiment, the first intake air flow rate M is obtained by the following formula_S(DK)：

Wherein A is the projected area of the opening of the throttle valve 180 in the direction perpendicular to the air intake pipe 120, and P₀Is a first pressure, M is the molar mass of air, k is the adiabatic index of air, R is the gas constant, T₀Is the first temperature and Y is the gas expansion factor.

In this embodiment, when the ratio P of the second pressure to the first pressure is smaller_S/P₀When it is less than 0.5283, the first intake air flow rate is obtained where Y is 1.

In this embodiment, when the ratio P of the second pressure to the first pressure is smaller_S/P₀Above 0.5283, Y in the equation for obtaining the first intake air flow rate is calculated by the equation:

in the present embodiment, the second intake air flow rate M is obtained by the following formula_S(P)：

Wherein: n is crankshaft speed, M is air molar mass, P_SAt a second pressure, V is the displacement of the cylinder, R is the gas constant, T_SIs the second temperature.

In this embodiment, the preset value is 10kg/h to 20 kg/h.

In the present embodiment, when the first intake air flow rate is equal to the second intake air flow rate or the difference between the first intake air flow rate and the second intake air flow rate does not reach a preset value, it is determined that the ventilation pipe 170 is not disconnected. When the ventilation pipe 170 is disconnected, external air enters the intake pipe 120 through the disconnected portion of the ventilation pipe due to a certain negative pressure in the intake pipe 120, which causes an increase in the cylinder intake air flow rate and an increase in the engine load. To control the engine load at the target load, the intake air flow rate of the cylinder is maintained at the first intake air flow rate before occurrence of leakage. The engine controller controls the throttle valve 180 to close, and at this time, since the throttle valve 180 is closed, the second intake air flow rate calculated from the opening degree of the throttle valve 180, the pressure of the supercharger 130, and the pressure in the intake pipe 120 is also reduced, resulting in the first intake air flow rate being smaller than the second intake air flow rate. When the deviation between the first intake air flow and the second intake air flow reaches a preset value, it can be determined that a disconnection fault has occurred in the ventilation pipe. And when the first intake air flow rate is equal to the second intake air flow rate or the difference between the first intake air flow rate and the second intake air flow rate is less than the preset value, it is determined that the ventilation pipe 170 is not disconnected.

Referring to fig. 3, the abscissa of fig. 3 is time and the ordinate is intake air flow rate, and it can be known from the figure that the first intake air flow rate is smaller than the second intake air flow rate after the ventilation pipe is disconnected.

In summary, in the method for determining disconnection of the ventilation line and the ventilation system of the engine according to the embodiment of the present invention, the ventilation line 120 of the crankcase 160 is communicated with the intake line 120 of the cylinder 150, so as to ventilate the crankcase 160, and whether the ventilation line 170 is disconnected or not can be detected by calculating the flow rate of intake air of the engine, so as to prevent blow-by gas from leaking into the atmosphere and causing environmental pollution.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.