JP6838289B2 - How to measure the amount of fuel in the exhaust gas - Google Patents

Description

The present invention relates in advance the amount of fuel measured how in the exhaust gas can be used in such analysis in the exhaust gas of an internal combustion engine.

In internal combustion engines such as diesel engines, in order to improve the purification performance of the exhaust gas purification device and regenerate it, unburned fuel is supplied and burned to raise the temperature of the exhaust gas, and the amount of this unburned fuel supplied. It is becoming important to measure the amount of unburned fuel in the exhaust gas for the purpose of optimizing the fuel and evaluating the performance of the exhaust gas purification device.

Conventionally, the amount of unburned fuel in the exhaust gas is measured by passing a certain amount of the exhaust gas through the filter and using gas chromatography (GC) and mass spectrometry (MS) to collect the unburned fuel by the filter. Polycyclic aromatic hydrocarbons and the like are measured by GC / MS analysis (see, for example, Patent Document 1).

However, in this measurement method, the area of the chromatogram of the measured specific ion can be quantified by using the chromatogram consisting of the elution time (retention time) required for the separation of the unburned fuel and the amount detected at that time. The amount of unburned fuel is calculated and obtained by approximating using the area, but there is a problem that real-time measurement cannot be performed because the unburned fuel collected by the filter is analyzed.

Japanese Unexamined Patent Publication No. 2009-175048

The present invention has been made in view of the above, and its object is advance fuel in the exhaust gas can be measured in real time the advance amount of fuel in exhaust gas discharged from an internal combustion engine or the like in a relatively simple measurement system It is to provide an amount of measuring how.

The method for measuring the amount of unburned fuel in the exhaust gas of the present invention for achieving the above object is to measure the amount of unburned fuel contained in the exhaust gas to be measured generated by the combustion of fuel in an internal combustion engine. the measuring method of the amount of unburned fuel, to eliminate the non-volatile components in the measurement object, when measuring only volatile components in the exhaust gas mass spectrometry were analyzed introduced into the mass spectrometer without passing through the gas chromatography It is characterized in that the amount of unburned fuel in the exhaust gas is calculated from the result of the analysis and the result of the preliminary analysis in which the fuel sample used in the internal combustion engine is analyzed in advance.

According to this method, when analyzing the amount of unburned fuel contained in the exhaust gas to be measured by using a mass spectrometer, a mass spectrometer is used instead of gas chromatography, so that the analytical instrument is simplified. , It is possible to measure during running in an internal combustion engine mounted on an automobile.

More specifically, in the above-mentioned method for measuring the amount of fuel in the exhaust gas, as the preliminary analysis, a GC / MS analyzer comprising gas chromatography and a mass spectrometer for a fuel sample used in the internal combustion engine. It analyzed using, together with obtaining the intensity ratio of the ionic strength of certain of the ionic strength and molecular ion corresponding to the fuel component in the fuel, in relation to the weight of the fuel component and the ionic strength of the specific ions A certain calibration curve is obtained, and as the analysis at the time of measurement, the ion intensity of the molecular ion in the mass spectrum is measured, and the ion intensity of the specific ion corresponding to the molecular ion is determined from the ion intensity of the molecular ion and the intensity ratio. together to calculate, by multiplying the converted value obtained from the previous SL calibration curve to a sum of the ionic strength of the calculated by said identified ions calculated mass of the fuel component, the mass of the fuel component this calculated The total amount is the amount of unburned fuel in the exhaust gas.

Alternatively, more specifically, in the above-mentioned method for measuring the amount of fuel in the exhaust gas, as the preliminary analysis, a sample of the fuel used in the internal combustion engine is subjected to GC / MS including gas chromatography and mass spectrometer. spectrometer and analyzed using the intensity ratio of the ionic strength of certain of the ionic strength and molecular ion corresponding to the fuel component in the fuel, in relation to the mass of the ionic strength and the fuel component of the specific ions A specific calibration line is obtained, and the specific total ion consisting of the specific ion and its surroundings in the total ion chromatogram that represents all ions with the ion intensity of the specific ion in the selective ion chromatogram that represents only the selected ion. The conversion coefficient corresponding to the molecular ion is obtained by dividing the ion intensity of the above, and the ion intensity of the molecular ion in the mass spectrum is measured as the analysis at the time of measurement, and the ion intensity of the molecular ion and the intensity ratio correspond to the molecular ion. In addition to calculating the ion intensity of the specific ion, the mass of the fuel component is calculated by multiplying the calculated sum of the ion intensity of the specific ion by the conversion coefficient and the conversion value obtained from the calibration line. The calculated mass of the fuel component is integrated to obtain the amount of unburned fuel in the exhaust gas.

As a result, the amount of unburned fuel can be calculated from the ionic strength of molecular ions with a relatively simple algorithm, so that the amount of unburned fuel in the exhaust gas can be measured in real time.

Further, in the above-mentioned method for measuring the amount of unburned fuel in exhaust gas, the mass-charge ratio corresponding to the molecular weight of a linear saturated hydrocarbon having a hydrocarbon number of 15 or more and 26 or less as the specific ion and the mass-charge ratio of fragment ions. However, when 57, 71, and 85 ions are used, the measurement method uses linear saturated hydrocarbons contained in the fuel of the diesel engine as specific ions, so that the amount of unburned fuel in the exhaust gas of the diesel engine can be measured. This is a suitable method.

Further, in the above method for measuring the amount of unburned fuel in the exhaust gas, the non-volatile component in the exhaust gas to be measured is eliminated by colliding the exhaust gas with a heated collision member or passing it through a heated filter. With a relatively simple configuration, non-volatile components in the exhaust gas can be easily eliminated.

According to advance the fuel amount measuring method in the exhaust gas of the present invention, when analyzed using a mass spectrometer to advance the amount of fuel contained in the exhaust gas to be measured, since the analysis without the use of gas chromatography analysis The equipment will be simplified and the amount of fuel can be calculated in real time.

It is a figure which shows typically the structure of the system used for the method of measuring the amount of unburned fuel in the exhaust gas of embodiment which concerns on this invention. It is a figure which shows typically the structure of the mass spectrometer of FIG. It is a figure which shows the structure of the step in the method of measuring the amount of unburned fuel in the exhaust gas of the embodiment which concerns on this invention. It is a figure which shows an example of the chromatogram obtained by the mass spectrometer. It is a figure which shows an example of the mass spectrum obtained by the mass spectrometer. It is a figure which shows the 1st example of the mass spectrum which shows the relationship of the count of a specific ion and a molecular ion in a fuel component. It is a figure which shows the 2nd example of the mass spectrum which shows the relationship of the count of a specific ion and a molecular ion in a fuel component. It is a figure which shows the 3rd example of the mass spectrum which shows the relationship of the count of a specific ion and a molecular ion in a fuel component. It is a figure which shows the calibration curve which shows the relationship between a specific ion and the amount of a linear saturated hydrocarbon. It is a figure which shows an example of the chromatogram which shows the total amount (TIC) of the ion count of all the ranges to measure. It is a figure which shows an example of the chromatogram which shows the amount (SIC) of the ion count of only selected ions. It is a figure which shows an example of the chromatogram at the time of analysis of a fuel sample. It is a figure which shows the method of classification in the elution time of a chromatogram. It is a figure which shows the relationship between the SIC peak area and the TIC division area in a chromatogram. It is a figure which superimposes the chromatogram of only the selected ion with all the ions in the analysis of an exhaust gas. It is a figure which shows the example of the mass spectrum which shows the mass fragment of the exhaust gas which shows the relationship between the count of a specific ion and the count of a molecular ion in the analysis of an exhaust gas. It is a figure which shows typically the structure of the GC / MS analyzer used for the analysis of the fuel sample. It is a figure which shows the working procedure in the analysis of the fuel sample using a GC / MS analyzer.

It will be described below with reference to the drawings attached to the measuring how advance the amount of fuel in the exhaust gas of the embodiment according to the present invention.

First, the system used for the method of measuring the amount of fuel in the exhaust gas according to the embodiment of the present invention will be described. As shown in FIG. 1, the measurement system 1 for the amount of unburned fuel in the exhaust gas includes a measurement pipe 21, a heating collision portion 22, and a mass spectrometer 30, and is an exhaust gas passage through which the exhaust gas G to be measured passes. The exhaust pipe 11 of a certain internal combustion engine (hereinafter, engine) 10 and the mass spectrometer 30 are connected by a measuring pipe 21.

Further, a heating collision portion 22 is provided in the middle of the measurement pipe 11, and a heating collision member 22a that collides the inside of the heating collision portion 22 with a particulate matter such as soot of exhaust gas G introduced into the measurement pipe 21. In addition to being arranged, as shown in FIG. 2, the mass spectrometer 30 includes a mass spectrometer (MS: mass spectrometry) 30a and a calculation device 30b including a calculation unit 34. The mass spectrometer 30a includes an ionization chamber 31, a quadrupole 32, and an ion detector 33.

Then, as shown in FIG. 1, a probe 23 is provided at a portion inserted into the exhaust pipe 11 on the tip end side of the measurement pipe 21, and a flow rate adjusting valve 24 and suction are provided in the middle of the measurement pipe 21. A pump 25 is provided. Further, an exhaust gas pipe 26 for discharging the exhaust gas G that is no longer needed by the mass spectrometer 30 is provided, and after purifying the exhaust gas G by an exhaust gas purification device (not shown) provided in the exhaust gas pipe 26, the atmosphere is reached. Release inside.

Further, the heating collision portion 22 is connected to the exhaust pipe 11 by the measurement pipe 21 on the inlet side of the exhaust gas G and to the mass spectrometer 30 by the measurement pipe 21 on the outlet side of the exhaust gas G. Further, inside the heating collision portion 22, the heating collision member 22a is arranged so as to face the outlet of the measurement pipe 21. At the time of measurement, an electric heater or the like is used at 400 ° C. or higher to 600 ° C. (to prevent thermal decomposition and carbonization) so that the organic matter adhering to the surface of the particulate matter that collides with the thermal collision member 22a can be volatilized. It is configured so that it can be heated to the following extent.

The heating collision member 22a has a simple structure when formed in a plate shape. Further, a gap 22c is provided between the periphery of the heating collision member 22a and the wall surface 22b of the heating collision portion 22. The exhaust gas G that has collided with the heating collision member 22a passes through the gap 22c and flows into the measurement pipe 21 through an opening 21a provided next to the measurement pipe 21 connected to the back side of the heating collision member 22a. Therefore, the exhaust gas G containing the volatilized component is introduced from the measurement pipe 21 into the mass spectrometer 30a. On the other hand, the non-volatile particulate matter that has collided with the heating collision member 22a adheres to the heating collision member 22a and is separated from the exhaust gas G.

In addition, as the heating collision member 22a, a filter (not shown) heated at 400 ° C. or higher and 600 ° C. or lower (to prevent thermal decomposition and carbonization) may be provided instead of the plate material. The introduced exhaust gas G is passed through this heated filter to volatilize the organic substances adhering to the surface of the particulate matter, and the non-volatile components such as the particulate matter such as soot are captured by the filter to cause the volatile components. And the non-volatile component are separated, and the exhaust gas G containing only the volatilized component is introduced into the mass analyzer 30a from the measurement pipe 21.

Then, in sampling the exhaust gas G when measuring the amount of unburned fuel in the exhaust gas G, the exhaust gas G is diverted from the exhaust pipe 11 of the engine 10 and introduced into the measurement pipe 21. The exhaust gas G introduced into the measurement pipe 21 is made to collide with the heating collision plate 22a provided in the middle of the measurement pipe 21 to volatilize the organic matter adhering to the surface of the particulate matter contained in the exhaust gas G. , The exhaust gas G containing the volatile component is introduced into the mass spectrometer 30a.

As shown in FIG. 2, each component in the exhaust gas G introduced into the mass spectrometer 30a is ionized in the ionization chamber 31 by the electron impact method (EI ionization method). As the ionizing voltage, 10 eV to 70 eV is used. The ions It of each component ionized in the ionization chamber 31 are made to fly by electrostatic force and pass through the quadrupole 32.

By changing the voltage in the quadrupole 32 to change the strength of the electric field, only specific ions Is can reach the detector 33. Thereby, the ions can be separated and sorted according to the mass-to-charge ratio (m / z: m is the mass of the ions and z is the charge).

The selected ion Is is sensitized and detected by a detector 33 with an electron multiplier tube or a microchannel plate, the number of the ion Is is counted, and the number of the ion Is is converted into an electric signal according to the count number to be converted into an electric signal. It is sent to the arithmetic unit 34 of 30b. The number of this count becomes the ionic strength of the ion Is.

The mass spectrum (mass spectrum) as shown in FIG. 5 can be obtained from the electric signal converted by the detector 33. The horizontal axis is the mass-to-charge ratio, and the vertical axis is the detected ionic strength (count).

In this mass spectrum, ions with only one positive or negative charge, polyvalent ions charged with divalent or higher, fragment ions (Fin, Fim) dissociated during the ionization process or flight, and samples are associated with each other. Associative ions appear. Normally, the molecule contains isotope elements, and each peak appears with a unique distribution of the molecule derived from it. And since the mass spectrum contains all of this information, it becomes a considerably complicated spectrum.

As shown in FIGS. 1 and 2, the method for measuring the amount of unburned fuel in the exhaust gas according to the embodiment of the present invention excludes the non-volatile component in the exhaust gas G to be measured and eliminates the volatile component in the exhaust gas G. The result of mass spectrometry at the time of measurement, which was analyzed by introducing only the sample into the mass spectrometer 30a without passing through gas chromatography, and a sample of a fuel that generates exhaust gas G to be measured in advance as shown in FIG. Is a method of calculating the amount of unburned fuel in the exhaust gas G from the result of the preliminary analysis analyzed by using the GC / MS spectrometer 40 including the gas chromatography 40a and the mass spectrometer 30a.

Then, in this method of measuring the amount of unburned fuel in the exhaust gas, as a preliminary analysis, a sample of the fuel used in the engine 10 is subjected to gas chromatography (GC) 40a and mass spectrometry (MS) as shown in FIG. : Mass spectrometer) 30a is directly connected, and a sample from gas chromatography (GC) 40a is analyzed by a GC / MS (GCMS) analyzer 40 for mass spectrometry.

In this GC / MS analysis, a sample (sample) driven by a syringe (not shown) or the like is vaporized in a high-temperature vaporization chamber (not shown), and then gas chromatography (GC) is performed by a carrier gas used as a mobile phase. ) Move from the GC injector 41 of 40a to the capillary column 42. An inert gas such as helium, nitrogen, or argon is used as this carrier gas, and the sample is carried by this carrier gas.

This sample is separated into each component by the principle of chromatography in a capillary column 42 in which a stationary phase for component separation is applied to the inner wall of a tube having an inner diameter of 1 mm or less of molten quartz.

Each component of the sample separated by this elution time (retention time: time elution from the capillary column) and carried to the carrier gas is further sent to the mass spectrometer 30a. In this mass spectrometer 30a, each component contained in the sent carrier gas is ionized in a vacuum applied with a high voltage in the ionization chamber 31, and each of the ionized components is made to fly in the apparatus by electrostatic force. Then, the ions are separated by the quadrupole 32 by electrical and magnetic action according to the mass spectrometry ratio, and the ions selected by the quadrupole 32 are separated by the detector 33 in an electron multiplying tube or micro. Sensitize with a channel plate for detection.

This work flow is shown in FIG. In this work flow, in step S21 of the pretreatment step S20, the soluble component of the fuel sample to be measured is extracted with an organic solvent, and in step S22, the soluble component of the fuel sample is injected into the GC injector 41. .. On the other hand, in step S23, the volatile component of the fuel sample is introduced into the GC injector 41 by thermal desorption. In step S31 of the next GC separation step S30, the mixture is separated by the capillary column 42, and in step S41 of the next detection step S40, the component eluted from the capillary column 42 is detected by the mass spectrometer 30a.

The detector 33 converts the electrical signal into an electric signal, and the time is taken on the horizontal axis and the signal intensity obtained from the detector 33 is taken on the vertical axis to obtain a chromatogram as shown in FIG. Be done. In this chromatogram, the substance is identified from the elution time tr indicated by the horizontal axis, and the quantification is performed from the height or area of the chromatogram called the peak P (i) on the vertical axis. In the chromatogram used here, the number of detected ions is shown.

An example of a chromatogram obtained when a sample of this fuel is analyzed is shown in FIG. For example, in the analysis results when JIS light oil is used as fuel, assuming that the horizontal axis is the elution time tr, the peak P (i) of the linear saturated hydrocarbon is periodically spaced at regular intervals with respect to this elution time tr. appear. That is, hydrocarbons are classified into alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, etc. according to their molecular structure, but most of the fuel components are linear saturated hydrocarbons, and these linear saturated hydrocarbons are used. Since the peak P (i) of hydrogen appears, this peak P (i) is used as a reference.

Then, some (a, b) of specific ions corresponding to the fuel component (for example, a linear saturated hydrocarbon having 15 to 26 carbon atoms (normal alkane: n-alkane)) in the fuel sample are selected and set. I will do it. In this selection, it is preferable to select fragment ions and molecular ions having a high production rate of mass fragment patterns obtained by an electron impact method (EI ionization method) that differs for each molecule. When ions having mass-to-charge ratios of 57, 71, and 85 are used as the specific ions (fragment ions having a high production ratio), a measurement method using linear saturated hydrocarbons contained in the fuel of a diesel engine as specific ions can be used. Therefore, it becomes a method suitable for measuring the amount of unburned fuel in the exhaust gas of a diesel engine, which is more preferable. In the following, for the sake of simplicity, the specific ions will be described with two (a, b), but the present invention is not limited to two.

Further, a mass spectrum of linear saturated hydrocarbons separated by gas chromatography (GC), as shown in FIGS. 6 to 8, is obtained. 6 to 8 show the relationship between the count p (j) of the three molecular ions p and the counts a (j) and b (j) of the specific ions a and b. That is, in FIGS. 6 to 8, the counts “a (n), b (n)” and “a (n)” of the specific ions a and b with respect to the counts p (n), p (m) and p (o) of the molecular ions p, respectively. “A (m), b (m)”, “a (o), b (o)”) are shown, respectively.

Furthermore, at the time of analysis of fuel data, the counts of specific ions a and b (number of ions) ac (j) and bc (j) and the count p (j) of molecular ions p are detected, and these are detected. The intensity ratio, which is the value of the ratio, α (j) = ac (j) / pc (j), β (j) = bc (j) / pc (j) is calculated. The subscript "c" next to "a", "b", and "p" represents the value at the time of analysis of the fuel sample.

This makes it possible to estimate the counts am (j) and bm (j) of the specific ions a and b from the count pm (j) of the molecular ions p detected during the analysis of the exhaust gas. That is, “am (j) = α (j) × p (j)” and “bm (j) = β (j) × pm (j)”. The subscript "m" next to "a", "b", and "p" represents the value at the time of exhaust gas analysis.

Further, as shown in FIG. 9, the ionic strength (count) P (i) (= at, bt) of these specific ions (i = a, b) and these specific ions P (i) (= a, Calibration curve L (i) (= L (a)) showing the relationship with the mass (linear saturated hydrocarbon amount) M (i) (= M (a), M (b)) of the fuel component corresponding to b). , L (b)) is created and prepared. Specifically, a conversion value for obtaining the mass (linear saturated hydrocarbon amount) M (i) (= M (a), M (b)) of the fuel component from the intensities at and bt of the specific ions a and b. C (i) (= C (a), C (b)) is set.

That is, the amount of linear saturated hydrocarbon M (a) corresponding to the intensity at of the specific ion a is “M (a) = C (a) × at”, and the linear saturation corresponding to the intensity bt of the specific ion b. The amount of hydrocarbon M (b) can be calculated by "M (b) = C (b) x bt". That is, "M (i) = C (i) x P (i)".

Further, since the fuel contains a compound having a boiling point close to that of each linear saturated hydrocarbon at a constant ratio, the conversion coefficient k (i) for obtaining the fuel amount including the surrounding compounds is obtained. It is preferable to keep it.

In this regard, in the analysis using the mass spectrometer 30a, the chromatograph as shown in FIG. 4 can be drawn for each selected ion, and as shown in FIG. 10, all measurements are made. Both TIC (Total Ion Counts) indicating the total amount of total ion counts in the range of and SIC (Selected Ion Counts) indicating the amount of selected ion counts of only selected ions can be represented. ..

In this chromatogram analysis, the chromatogram is divided on an elution time basis as shown in FIG. 13 to determine the conversion factor k (i). This division point is an intermediate point ts (i) of adjacent peaks (P (i), P (i + 1)), and one division Δts (i) has two peaks (P (i-1)) with respect to the elution time tr. ), From the midpoint ts (i-1) of P (i)). It is up to the midpoint ts (i) of the next two peaks (P (i), P (i + 1)).

Next, as shown in FIG. 14, the total amount of total ion counts in the entire range to be measured with respect to the area from the midpoint ts (i-1) to the midpoint ts (i) of the target peak P (i) is shown. The TIC division area At (i) is defined by TIC, and the area of the peak portion corresponding to the peak P (i) in SIC indicating the amount of selected ion count of only the selected specific ion fragment is determined as the SIC peak area Ap (i). .. The SIC peak area Ap (i) is the area of only the linear saturated hydrocarbon, and the TIC division area At (i) is the area of the sum of the linear saturated hydrocarbon and the compounds around it.

Then, in the analysis of the fuel sample in the preliminary analysis, the TIC division area At (i) of the total amount ion chromatogram representing the total amount TIC of the ion count in the entire range to be measured and the selection to count only the selected specific ion fragment are selected. The SIC peak area Ap (i) of the selected ion chromatogram representing the ion count SIC is calculated.

Using these areas, a conversion coefficient k (i), which is a value of the ratio of the TIC division area At (i) and the SIC peak area Ap (i), is set for each peak P (i) of the chromatogram. i) = (TIC division area / SIC peak area) = (Act (i) / Acp (i)) ”. Thereby, the TIC division area At (i) can be estimated from the SIC division area As (i). “Act (i) = k (i) × Acs (i)”. The area Ac when calculating the conversion coefficient k (i) is obtained when the fuel sample is analyzed, and is different from the area Am when the exhaust gas is analyzed. Therefore, the area when the fuel sample is analyzed. Is set to Ac.

That is, in the preliminary analysis, in the mass spectrum obtained by GC / MS analysis, the ions of the specific ions a and b corresponding to the specific fuel component (linear saturated hydrocarbon) in the fuel that generates the exhaust gas G to be measured The intensity ratios α (j) and β (j) of the intensities a (j) and b (j) to the ionic strength p (j) of the molecular ion p, the ionic strength P (i) of the specific ions a and b, and the fuel. The calibration line L (i), which is the relationship with the mass M (i) of the component, is obtained. Further, preferably, the ionic strengths Acs (i) of the specific ions a and b in the selected ion spectrum representing only the selected ions are composed of the specific ions a and b in the total ion spectrum representing all the ions and their surroundings. The conversion coefficient k (i) obtained by dividing the ionic strength Act (i) of all the specific ions is obtained.

Next, in the analysis performed on the exhaust gas, only mass spectrometry (MS: mass spectrometer) 30a is used without using gas chromatography (GC). In this case, the mass spectrum of the exhaust gas containing all of the molecular ions p as shown in FIG. 16 is obtained. In this case, the specific ions a and b corresponding to the specific fuel component (linear saturated hydrocarbon) overlap, but the molecular ions p (n), p (m), and p (o) have mass charges. They are separated because of the different ratios. In other words, the mass spectrum is as shown in FIG.

Then, in this exhaust gas analysis, the exhaust gas G is drawn from the probe 23 attached to the exhaust pipe 11 of the engine 10 by the suction pump 25 in a state of being adjusted to a constant flow rate by the flow rate adjusting valve 24, and the exhaust gas G is drawn from the exhaust pipe 11. It is guided to the measurement pipe 21 which is a sampling pipe, and further, the particulate matter of the exhaust gas G is made to collide with the heating collision member 22a of the heating collision portion 22 and adheres to the surface of the particulate matter contained in the exhaust gas G. The organic matter is volatilized, and the exhaust gas G containing the volatile component is introduced into the mass analyzer 30 to measure the amount of unburned fuel in the exhaust gas G.

In measuring the amount of unburned fuel in the exhaust gas G, the count (ionic strength) pm (j) of the molecular ions p (j = n, m, o) is detected from the mass spectrum of the exhaust gas as shown in FIG. To do. From the count pm (j) of the molecular ion p, it is the ratio of the count ac (j) and bc (j) of the specific ions a and b and the count pc (j) of the molecular ion p obtained by the preliminary analysis. Using the intensity ratios α (j) and β (j), the counts of specific ions am (j) and bm (j) are determined. That is, am (j) and bm (j) are calculated by "am (j) = α (j) × p (j)", “bm (j) = β (j) × pm (j)” and the like.

Then, the sum amt and bmt of the counts am (j) and bm (j) of the specific ions corresponding to the respective molecular ions are obtained. amt = Σam (j), bmt = Σbm (j). FIG. 16 represents "amt = am (n) + am (m) + am (o) + ..." and "bmt = bm (n) + bm (m) + bm (o) + ...".

Next, with respect to P (i), which is the sum of the counts am (j) and bm (j) of the specific ions a and b, and bmt, of the calibration curve L (i) set in the preliminary analysis. Using the converted value C (i), the mass (linear saturated hydrocarbon amount) M (i) of the fuel component corresponding to the specific ions a and b is calculated. Specifically, "M (i) = C (i) x P (i)", and more specifically, "M (a) = C (b) x amt", "M (a) =". C (b) × bmt ”.

Next, from the value M (i) of only the mass (the amount of linear saturated hydrocarbon) of the fuel component corresponding to the specific peak P (i), the identification including the peripheral compounds corresponding to the specific peak P (i) is also included. The mass Mf (i) of the fuel component of the above is calculated. In this calculation, the sum of the counts of specific ions amt and bmt correspond to the SIC peak area Amp (i) of the selected ion chromatogram representing the selected ion count SIC that counts only the selected ions. From i), the conversion coefficient k (i) is used to calculate the TIC division area Amt (i) of the total ion chromatogram representing the total ion count TIC. Since "Amt (i) = k (i) x Amp (i)", Mf (i) = k (i) x M (i) includes peripheral compounds corresponding to the specific peak P (i). The mass Mf (i) of the specific component of the fuel is calculated.

Then, the mass Mf (i) of the specific component of the fuel is integrated by the number of peaks P (i) to obtain the unburned fuel amount Mt (= ΣMf (i)) in the exhaust gas.

That is, in the measurement analysis, the ionic strength pm (j) of the molecular ion p is measured, and the ionic strength pm (j) of the molecular ion p and the intensity ratios α (j) and β (j) are used to determine the molecular ion p. The ionic strengths am (j) and bm (j) of the specific ions a and b corresponding to the above are calculated, and the sum of the calculated ionic strengths of the specific ions a and b am (j) and bm (j) amt, Multiply bmt by the conversion value C (i) obtained from the calibration line L (i) to calculate the mass M (i) of the fuel component, and integrate the calculated mass M (i) of the fuel component. Assuming that the amount of unburned fuel in the exhaust gas is Mt, the amount of unburned fuel Mt can be calculated from the ionic strength pm (j) of the molecular ions p, so that the amount of unburned fuel Mt in the exhaust gas can be measured in real time.

When the conversion coefficient k (i) has been obtained, the conversion coefficient k is converted to the sum of the ionic strengths am (j) and bm (j) of the specific ions a and b calculated by the measurement analysis. Multiply the converted value C (i) obtained from (i) and the calibration curve L (i) to calculate the mass M (i) of the fuel component, and integrate the calculated mass M (i) of the fuel component. Then, the amount of unburned fuel in the exhaust gas is Mt.

When the above analysis is displayed in steps, the step configuration is as shown in FIG. That is, the method S50 for measuring the amount of unburned fuel in the exhaust gas is composed of the following steps. That is, in the fuel sample analysis (pre-analysis) S50A, there are a first analysis step S51, an ion selection step S52, an intensity ratio calculation step S53, a calibration curve setting step S54, and a conversion coefficient calculation step S55. In the analysis of exhaust gas corresponding to the process (analysis at the time of measurement) S50B, there are a second analysis step S56, a specific ion intensity calculation step S57, a quantification step S58, and an unburned fuel amount calculation step S59.

The first analysis step S51 is a step of analyzing a sample of a fuel that generates exhaust gas G to be measured by using a GC / MS analyzer 40 including a gas chromatography 40a and a mass spectrometer 30a, and is an ion selection step S52. Is a step of selecting specific ions a and b from the ions constituting the mass spectrum from the mass spectrum corresponding to the peak for the fuel component in the gas chromatograph 40a obtained in the first analysis step S51.

Further, in the intensity ratio calculation step S53, the intensity ratio α (intensity ratio α (j) of the ionic strengths ac (j) and bc (j) of the specific ions a and b selected in the ion selection step S52 and the ionic strength p (j) of the molecular ion p j), β (j) is calculated, and the calibration curve setting step S54 is a calibration curve L (which shows the relationship between the ionic strengths at and bt of the specific ions a and b and the mass M (i) of the fuel component. This is the step of setting i).

Then, in the conversion coefficient calculation step S55, in the gas chromatograph obtained in the first analysis step S51, in the total ion chromatogram displaying all ions and the selected ion chromatogram displaying only selected ions, the total ion chromatogram is displayed. The conversion coefficient k (i) is calculated from the TIC division area Act (i), which is the area of the specific total ions, and the SIC peak area Accp (i), which is the area of the peaks of the specific ions a and b in the selected ion chromatogram. It is a step to do.

On the other hand, the second analysis step S56 of the analysis at the time of measurement is a step of analyzing the amount of unburned fuel in the exhaust gas to be measured by using the mass spectrometer 30a, and the specific ion intensity calculation step S57 is the second analysis step. In, the ionic strength pm (j) of the molecular ion p is measured, and the ionic strength am (j) of the specific ions a and b is obtained from the ionic strength pm (j) of the molecular ion p and the intensity ratios α (j) and β (j). This is a step of calculating j) and bm (j).

In the quantification step S58, the conversion value C (i) obtained from the calibration line L (i) on the sum amt and bmt of the ionic strengths am (j) and bm (j) of the specific ions a and b in the specific ionic strength calculation step S7. Is a step of multiplying the fuel component mass M (i) to calculate the fuel component mass Mf (i), or further multiplying the multiplied value by the conversion coefficient k (i) to calculate the fuel component mass Mf (i). In the unburned fuel amount calculation step S59, the mass M (i) or Mf (i) of the fuel component calculated in the quantification step S58 is integrated, and this integrated value is taken as the unburned fuel amount Mt in the exhaust gas. It is a step to do.

According to this method for measuring the amount of unburned fuel in the exhaust gas, the ratio of specific ions to molecular ions of the fuel component (for example, linear saturated hydrocarbon) in the fuel is obtained in advance, and the strength of the specific ions and the fuel A calibration line L (i) showing the relationship with the mass of the component is prepared, the exhaust gas G to be measured is introduced into the measurement pipe 21, introduced into the mass spectrometry (MS) of the mass spectrometer 30, and the electrons are introduced. Ionization of molecules by collision is performed, and the ion strength of the molecular ion loaded with electrons on the molecule obtained at this time is detected, the relationship between the ion strength of this molecular ion and the ion strength of the specific ion is obtained, and the ion of the specific ion is obtained. The mass of the fuel component is quantified based on the strength.

Then, based on these, when measuring the unburned fuel in the exhaust gas, the strength of the specific ions in the exhaust gas is multiplied by the ion strength of the molecular ions corresponding to each fuel component in advance. Can be calculated, the mass of each fuel component can be quantified, and the mass of each of these fuel components can be integrated to calculate the amount of unburned fuel. At this time, since the fuel contains a compound having a boiling point close to that of each fuel component at a constant ratio, the amount of unburned fuel is calculated by correcting the mass of each fuel component with a conversion coefficient that takes this constant ratio into consideration. It is preferable to do so.

Furthermore, when analyzing the exhaust gas to be measured using an MS analyzer, if a selective ion chromatogram is used instead of a total ion chromatogram, the exhaust gas is contained in a relatively short time and with high accuracy. The amount of unburned fuel contained in can be determined.

According to the amount of unburned fuel measuring how in the exhaust gas of the above-described embodiments of the structure, when analyzed using a mass spectrometer amount of unburned fuel contained in the exhaust gas to be measured, a gas chromatography since analysis without, analytical instrument will be able to calculate the amount of unburned fuel in real time while being simplified.

Then, since the amount of unburned fuel in the exhaust gas discharged from the internal combustion engine or the like can be measured in real time, it is possible to measure the running time in the internal combustion engine or the like mounted on the automobile.

1 Measurement system for the amount of unburned fuel in exhaust gas 10 Internal combustion engine (engine)
11 Exhaust pipe 21 Measurement pipe 22 Heating collision part 22a Heating collision member 30 Mass spectrometer 30a Mass spectrometer 30b Computing device 31 Ionization chamber 32 Quadrupole 33 Ion detector 34 Calculation unit 40 GC / MS analyzer 40a Gas Chromatography (GC)
41 GC injector 42 Capillary column At (i), Act (i), Amt (i) Division area Ap (i), Ap (i), Amp (i) Peak area (area of peak part)
C (i) Calibration curve conversion value G Exhaust gas k (i) Conversion coefficient L (i) Calibration curve p (j) Molecular ions P (i), P (i + 1) Peak tr of fuel component (linear saturated hydrocarbon) Elution time (retention time: Retention Time)
ts (i-1), ts (i) partition point (midpoint of adjacent peaks)
Δts (i) classification

Claims (4)

In the method of measuring the amount of unburned fuel in the exhaust gas, which measures the amount of unburned fuel contained in the exhaust gas to be measured generated by the combustion of fuel in the internal combustion engine.
As a preliminary analysis, a sample of the fuel used in the internal combustion engine is analyzed using a GC / MS analyzer consisting of gas chromatography and a mass spectrometer, and the ion intensity of a specific ion corresponding to the fuel component in the fuel is determined. The intensity ratio of the molecular ion to the ion intensity is obtained, and the calibration line which is the relationship between the ion intensity of the specific ion and the mass of the fuel component is obtained.
As a measurement analysis of mass spectrometry analyzed by excluding the non-volatile components in the exhaust gas to be measured and introducing only the volatile components in the exhaust gas into a mass spectrometer without passing through gas chromatography, the above-mentioned in the mass spectrum. The ion intensity of the molecular ion is measured, the ion intensity of the specific ion corresponding to the molecular ion is calculated from the ion intensity of the molecular ion and the intensity ratio, and the sum of the calculated ion intensity of the specific ion is calculated. wherein by multiplying the converted value obtained from the calibration curve to calculate the mass of the fuel component, characterized in that the amount of unburned fuel in the exhaust gas by integrating the mass of the fuel component this is calculated A method for measuring the amount of unburned fuel in exhaust gas. In the method of measuring the amount of unburned fuel in the exhaust gas, which measures the amount of unburned fuel contained in the exhaust gas to be measured generated by the combustion of fuel in the internal combustion engine.
As a preliminary analysis, a sample of the fuel used in the internal combustion engine is analyzed using a GC / MS analyzer consisting of gas chromatography and a mass spectrometer, and the ion intensity of a specific ion corresponding to the fuel component in the fuel is determined. The intensity ratio of the molecular ion to the ion intensity, the calibration line which is the relationship between the ion intensity of the specific ion and the mass of the fuel component are obtained, and further, the specification in the selected ion chromatogram showing only the selected ion. The conversion coefficient obtained by dividing the ion intensity of the specific ion consisting of the specific ion and its surroundings in the total ion chromatogram representing all ions by the ion intensity of the ion is obtained, and at the same time.
As a measurement analysis of mass spectrometry analyzed by excluding the non-volatile components in the exhaust gas to be measured and introducing only the volatile components in the exhaust gas into a mass spectrometer without passing through gas chromatography, the above-mentioned in the mass spectrum. The ion intensity of the molecular ion is measured, the ion intensity of the specific ion corresponding to the molecular ion is calculated from the ion intensity of the molecular ion and the intensity ratio, and the sum of the calculated ion intensities of the specific ion. wherein by multiplying the converted value obtained conversion factor and from the calibration curve to calculate the mass of the fuel component, to the amount of unburned fuel in the exhaust gas by integrating the mass of the fuel component this is calculated A method for measuring the amount of unburned fuel in exhaust gas, which is characterized by. Claim 1 or 2 uses ions having a mass-to-charge ratio corresponding to the molecular weight of a linear saturated hydrocarbon having a carbonation number of 15 or more and 26 or less and a mass-to-charge ratio of fragment ions of 57, 71, 85 as the specific ions. The method for measuring the amount of unburned fuel in the exhaust gas described in. In the method of measuring the amount of unburned fuel in the exhaust gas, which measures the amount of unburned fuel contained in the exhaust gas to be measured generated by the combustion of fuel in the internal combustion engine.
By colliding the exhaust gas to be measured with a heated heating collision member or passing it through a heated filter, the non-volatile components in the measurement target are eliminated, and only the volatile components in the exhaust gas are subjected to gas chromatography. From the result of the measurement analysis of the mass spectrometry that was introduced into the mass spectrometer without passing through and the result of the pre-analysis that analyzed the fuel sample used in the internal combustion engine in advance, it is unburned in the exhaust gas. A method for measuring the amount of unburned fuel in exhaust gas, which comprises calculating the amount of fuel.

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