JP2543884B2 - Engine fuel vaporization rate detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine fuel vaporization rate detection device for detecting the vaporization rate of fuel supplied to a fuel chamber or the like of an automobile engine.

(Prior Art) To understand the fuel efficiency of an automobile engine,
It is necessary to accurately and quickly detect the state of the air-fuel mixture supplied to the fuel chamber of the engine. Therefore, conventionally, for example, as shown in Japanese Utility Model Application Laid-Open No. 58-26660, the sample gas discharged from the engine is introduced into a sample gas introduction pipe provided with an oxidation catalyst heated to 300 ° C. or higher. After completely oxidizing CO and various HCs in this sample gas, the concentration of CO ₂ was analyzed by a quadrupole mass spectrometer, and the air-fuel ratio of the air-fuel mixture was calculated based on this. There is. But,
In this configuration, since it takes a considerable time to completely oxidize the CO and various HCs, the response is poor, and a heating device for heating the oxidation catalyst to a high temperature is required. There is the problem of complexity.

Further, since the fuel efficiency of the engine is affected by whether the fuel in the air-fuel mixture is in the vaporized state or in the liquid state, that is, in the particulate state, the detection device capable of properly detecting the vaporization rate of the fuel Development was desired.

(Object of the Invention) The present invention has been made based on the above technical background, and it is possible to accurately and quickly detect the vaporization rate of the fuel supplied to the fuel chamber and the like of the engine with a simple configuration. A fuel vaporization rate detection device for an engine is provided.

(Structure of the Invention) According to the present invention, a vacuum passage into which an air-fuel mixture of an engine is introduced, an air-fuel mixture amount detection unit that obtains an amount of the air-fuel mixture to be introduced into the vacuum passage, and the air-fuel mixture is introduced. A pressure sensor that measures the degree of vacuum in the vacuum passage that changes with
A fuel vaporization rate detection device for an engine, comprising a quadrupole mass analyzer for measuring the ionic strength of components constituting the air-fuel mixture, and the air-fuel mixture amount obtained by the air-fuel mixture amount detection unit, and the pressure. A liquid fuel amount calculation unit for obtaining the liquid fuel amount in the air-fuel mixture based on the change state of the degree of vacuum detected by the sensor and the correlation of the liquid fuel amount obtained in advance corresponding to these values; Based on the air-fuel ratio calculation unit for calculating the air-fuel ratio of the air-fuel mixture based on the ion intensity measured by the polar mass spectrometer, the liquid fuel amount calculated by the liquid fuel amount calculation unit and the air-fuel ratio calculated by the air-fuel ratio calculation unit. And a control unit having a vaporization rate calculation unit for calculating the vaporization rate of the fuel.

According to the above configuration, the amount of the air-fuel mixture introduced into the vacuum passage, and the degree of vacuum in the vacuum passage which changes when the air-fuel mixture is introduced into the vacuum passage and the liquid fuel in the air-fuel mixture is vaporized, , The amount of liquid fuel in the air-fuel mixture is obtained according to the correlation corresponding to these values, and the air-fuel ratio of the air-fuel mixture is obtained by analyzing the components of the air-fuel mixture introduced into the quadrupole mass spectrometer. The vaporization rate can be calculated by calculating the ratio of the total amount of fuel contained in a predetermined amount of air-fuel mixture and the fuel in the vaporized state based on the liquid fuel amount and the air-fuel ratio. .

(Embodiment) FIG. 1 shows an embodiment of a fuel vaporization rate detecting device for an engine according to the present invention. This fuel vaporization rate detection device includes a first pressure sensor 3 for measuring the pressure of the air-fuel mixture supplied into the combustion chamber 2 of the engine 1, and a control valve 4 for taking out the air-fuel mixture in the combustion chamber 2 at a predetermined timing. And a vacuum passage 5 through which the air-fuel mixture is introduced as sample gas when the control valve 4 is opened.
A second pressure sensor 6 for measuring the degree of vacuum in the vacuum passage 5, and a first vacuum chamber 7 and a second vacuum chamber 8 arranged at the end of the vacuum passage 5 facing each other. ing.

Into the second vacuum chamber 8, an orifice 9 that regulates the flow rate of the sample gas introduced from the vacuum passage 5, a valve 10 for introducing the sample gas, a valve 11 for discharging the sample gas, and an inside of the second vacuum chamber 8 are introduced. A quadrupole mass analyzer 12 for measuring the ionic strength of each component in the sample gas is provided, and a turbo molecular pump 13 for evacuating the inside of the second vacuum chamber 8 to set a predetermined vacuum degree. And the rotary pump 14 is connected. When the control valve 4 is closed, the second
The vacuum passage 5 is set to a predetermined vacuum degree according to the degree of vacuum inside the vacuum chamber 8, and when the control valve 4 is opened, the sample gas is flown into the second vacuum chamber 8 through the orifice 9 at a predetermined flow rate. It is configured to be introduced in. The sample gas whose inflow into the second vacuum chamber 8 is blocked by the orifice 9 is connected to the first vacuum chamber 7 by the rotary pump.
It is designed to be discharged to the outside by 15.

The control valve 4 is controlled to open and close according to a control signal output from the control unit 17 of the control means 16 including a microcomputer or the like. Then, the mixed pressure in the engine fuel chamber 2 when the control valve 4 is opened is measured by the first pressure sensor 3 described above.
And the detected value is detected by the air-fuel mixture amount detection unit 18 of the control means 16.
By inputting into, the amount of air-fuel mixture introduced into the vacuum passage 5 is obtained. That is, since the degree of vacuum in the vacuum passage 5 is maintained at a constant level when the control valve 4 is closed, the flow rate of the air-fuel mixture introduced into the vacuum passage 5 when the control valve 4 is opened is equal to that of the fuel chamber. It changes according to the mixed atmospheric pressure in 2. Therefore, by constantly setting the open period of the control valve 4 by a timer or the like, the mixture gas introduced into the vacuum passage 5 according to the mixture pressure in the combustion chamber 2 detected by the first pressure sensor 3 can be controlled. The quantity can be calculated.

The second pressure sensor 6 detects a change in the degree of vacuum caused by the introduction of the air-fuel mixture into the vacuum passage 5, and inputs the detected value to the liquid fuel amount calculation unit 19 of the control means 16, By inputting the amount of the air-fuel mixture obtained by the air-fuel mixture amount detection unit 18 into the liquid fuel amount calculation unit 19, the liquid fuel amount calculation unit is configured to obtain the liquid fuel amount contained in the air-fuel mixture. Has been done. That is, the degree of vacuum in the vacuum passage 5 is temporarily lowered by introducing the air-fuel mixture into the vacuum passage 5. At this time, the air-fuel mixture is rapidly depressurized to vaporize the amount of liquid fuel in the air-fuel mixture, so that the amount of decrease in the degree of vacuum changes according to the amount of liquid fuel. Therefore, it is possible to obtain the output signal of the detection unit 19 and the detection signal of the second pressure sensor 6 by previously obtaining the correlation between the change state of the air-fuel mixture amount and the degree of vacuum and the corresponding liquid fuel amount. Accordingly, the liquid fuel amount in the air-fuel mixture can be read by the liquid fuel amount calculation unit 19.

As shown in FIG. 2, the quadrupole mass spectrometer 12 collects the ionized components by ion bombarding each component in the sample gas by electron bombarding each component and ionizing each component. An electrode unit 22 composed of a lens system 21 for forming an ion beam and four rods for vibrating the ions incident through the lens system 21 and allowing only ions having a specific charge ratio to pass therethrough.
And a secondary electron multiplier 23 that detects the ionic strength of the ions that have passed through the electrode portion 22 as an ionic current. Then, by adjusting the voltage value applied to the electrode portion 22, ions of a specific charge ratio, that is, various HC ions and ionic strength of O ₂ ⁺ etc. are selectively detected, and various HC ions contained in the air-fuel mixture are detected. The ionic strength of O ₂ ⁺ is output to the air-fuel ratio calculation unit 24 of the control means 16 as a detection signal indicating the fuel amount, and the ionic strength of O ₂ ⁺ is output to the air-fuel ratio calculation unit 24 as a detection signal indicating the air amount. It is configured.

The air-fuel ratio calculation unit 24 calculates the ion intensity of various HC ions and
Calculate the air-fuel ratio of the mixture based on the ionic strength of O ⁺ ,
The value is output to the vaporization rate calculator 25.
The vaporization rate calculation unit 25 determines the total amount according to the detection signal of the liquid fuel amount in the mixture output from the liquid fuel amount calculation unit 19 and the detection signal of the air-fuel ratio output from the air-fuel ratio calculation unit 24. The ratio of the vaporized fuel amount (the value obtained by subtracting the liquid fuel amount from the total fuel amount) to the fuel amount is calculated as the vaporization rate.

A control operation in the case of detecting the vaporization rate of the air-fuel mixture introduced into the combustion chamber 2 of the engine 1 using the fuel vaporization rate detection device configured as described above will be described based on the flowchart shown in FIG. . First, before introducing the air-fuel mixture of the engine 1 into the above apparatus, the mass spectrum of each component is measured and stored using the standard air-fuel mixture. That is, a standard mixture whose constituents are known in advance is introduced into the quadrupole mass spectrometer 12 to determine the ionic strength of various HC ions, and the correspondence relationship between this ionic strength and the amount of each constituent is stored as a mass spectrum. To do.

Next, in step S ₂ , the control unit 17 controls the control valve 4
The control valve 4 is opened by outputting an open command signal to the air conditioner, and the air-fuel mixture in the combustion chamber 2 is introduced into the vacuum passage 5. Further, in step S ₃ , the detection value of the mixture atmospheric pressure in the combustion chamber 2 detected by the first pressure sensor 3 is used as the mixture amount detection unit 18
Then, in step S ₄ , the amount of air-fuel mixture introduced into the vacuum passage 5 is calculated in accordance with the above-mentioned air pressure. In step S _5, it is determined whether or not elapsed set time set in advance by a timer or the like, at the time that the setting time has elapsed has been confirmed, to close the control valve 4 in step S ₆ Output a control signal.

Next, in step S ₇ , the liquid fuel amount calculation unit 19 obtains the detected value of the degree of vacuum at the peak state when the change rate of the degree of vacuum of the vacuum passage 5 detected by the second pressure sensor 6, that is, the rate of decrease of the degree of vacuum is maximized. To enter. Then, in step S _8, the air-fuel mixture amount determined in step S _4,
A vacuum degree detection value input from the second pressure sensor 6;
Based on the correlation of the liquid fuel amount corresponding to these values, the liquid fuel amount in the air-fuel mixture introduced into the vacuum passage 5 is read.

Next, in step S ₉ , the ionic strength and O ₂ of various HC ions in the mixture measured by the quadrupole mass spectrometer 12 are measured.
The ionic strength of the ⁺ input to the air-fuel ratio calculator 24, Step S ₁₀
At, the air-fuel ratio of the air-fuel mixture is calculated according to these values. Since it is difficult to measure all of the HC ions when measuring the ionic strength of the HC ions, typical ones such as C ₄ H ₇ ⁺ and C ₅ H in each HC ion are difficult to measure.
The ionic strengths of ₉ ⁺ , C ₆ H ₉ ⁺ , C ₇ H ₇ ⁺ , C ₇ H ₁₁ ^+, etc. were measured, and based on the correlation between the ionic strengths of these representative ions and various HC total amounts, You may make it calculate the total amount of HC.

Then, in step S _11, to calculate the evaporation rate of the fuel on the basis of a liquid fuel content in the gas mixture obtained in step S _8, the air-fuel ratio of the mixture obtained in step S _10.

This way, the detection of the vaporization rate of a single engine 1 ends returns to step S _2, it starts to detect the vaporization rate of the other engine.

As described above, the vacuum passage 5 is removed from the combustion chamber 2 according to the mixed atmospheric pressure in the combustion chamber 2 detected by the first pressure sensor 3.
The amount of the air-fuel mixture introduced into the inside of the air-fuel mixture is detected, and the liquid state contained in the air-fuel mixture is detected according to the change state of the degree of vacuum in the vacuum passage 5 detected by the second pressure sensor 6 and the amount of the air-fuel mixture. Since the fuel amount is determined, and the air-fuel ratio of the air-fuel mixture is calculated according to the ionic strength of each component of the air-fuel mixture analyzed by the quadrupole mass analyzer 12, the liquid fuel amount in the air-fuel mixture is determined. The fuel vaporization rate can be calculated accurately and rapidly based on the air-fuel ratio of the air-fuel mixture.

In the above embodiment, the opening time of the control valve 4 is set to be always constant so that the amount of air-fuel mixture introduced into the vacuum passage 5 is calculated according to the detection value of the first pressure sensor 3. However, the opening time of the control valve 4 is detected by a sensor or the like, and the opening time and the pressure sensor 3 are detected.
It may be configured to calculate the air-fuel mixture based on the detected value of. In addition, an air flow meter or the like for directly measuring the amount of the air-fuel mixture introduced into the vacuum passage 5 may be provided.

Further, in the above embodiment, the air-fuel mixture is taken out as the sample gas from the combustion chamber 2 of the engine 1.
The control valve 4 and the vacuum passage 5 are connected to the intake passage of
The air-fuel mixture may be taken out as the sample gas from this intake passage.

(Effects of the Invention) As described above, the present invention is based on the amount of the air-fuel mixture introduced into the vacuum passage and the degree of vacuum of the vacuum passage changed by the introduction of the air-fuel mixture into the vacuum passage. The amount of liquid fuel contained in the air-fuel mixture is determined, and the air-fuel ratio of the air-fuel mixture is calculated according to the ionic strength of each component constituting the air-fuel mixture analyzed by the quadrupole mass spectrometer. There is an advantage that the vaporization rate of the fuel required for grasping the engine combustion efficiency can be accurately and quickly detected based on the amount of liquid fuel in the air and the air-fuel ratio of the air-fuel mixture.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall schematic diagram showing an embodiment of a fuel vaporization rate detection device according to the present invention, FIG. 2 is a schematic diagram showing the configuration of a quadrupole mass spectrometer, and FIG. It is a flowchart which shows the effect | action of a control means. 1 ... Engine, 5 ... Vacuum passage, 6 ... Pressure sensor (second pressure sensor), 12 ... Quadrupole mass analyzer, 16 ...
Control means, 18 ... Mixture ratio detection section, 19 ... Liquid fuel amount calculation section, 24 ... Air-fuel ratio calculation section, 25 ... Vaporization rate calculation section.

Claims (1)

(57) [Claims] 1. A vacuum passage into which an air-fuel mixture of an engine is introduced, an air-fuel mixture amount detecting unit for determining the amount of the air-fuel mixture introduced into the vacuum passage, and a vacuum which changes when the air-fuel mixture is introduced. A pressure sensor for measuring the degree of vacuum in the passage,
A fuel vaporization rate detection device for an engine, comprising a quadrupole mass analyzer for measuring the ionic strength of components constituting the air-fuel mixture, and the air-fuel mixture amount obtained by the air-fuel mixture amount detection unit, and the pressure. A liquid fuel amount calculation unit for obtaining the liquid fuel amount in the air-fuel mixture based on the change state of the degree of vacuum detected by the sensor and the correlation of the liquid fuel amount obtained in advance corresponding to these values; Based on the air-fuel ratio calculation unit for calculating the air-fuel ratio of the air-fuel mixture based on the ion intensity measured by the polar mass spectrometer, the liquid fuel amount calculated by the liquid fuel amount calculation unit and the air-fuel ratio calculated by the air-fuel ratio calculation unit. A fuel vaporization rate detection device for an engine, comprising: a control unit having a vaporization rate calculation unit for calculating a fuel vaporization rate.