JP2002214082A - Simultaneity correction apparatus for ensuring simultaneity in measurement of mass emission or fuel consumption quantity by high speed continuous measurement of flow rate and composition of exhaust gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain mass emission measuring technique enabling the correction of time because the flow rate of exhaust gas is also changed corresponding to a change in an operation state but it is necessary to ensure the simultaneity of a measured value of an exhaust gas flow rate and a gas analyzing value, when the discharge amount of a component is calculated from the direct measurement of the flow rate and component concentration of exhaust gas. SOLUTION: In an apparatus constituted so that the mass emission of the exhaust gas of a car is continuously measured at the outlet of an exhaust pipe by using a high speed response exhaust gas flowmeter 10 and a high speed response gas analyzer 16 and converted to mass concentration and a mass flow rate to operate momentary mass emission to calculate the same, an arithmetic circuit which automatically corrects the time related to the compositional change of the exhaust gas on the basis of operational expression: τ=a+273C/[q(273+t)] or calculation similar to this expression by using the measured value (q) of the flow rate of the exhaust gas converted to a standard state, the measured value (t) of the temperature of the exhaust gas, the definite constant C corresponding to the dead volume of an exhaust system, and the delay time (a) fixative to an exhaust gas analyzing system with respect to the synthetic delay time τ of the gas analyzed value to a flow rate measured value, is provided to ensure the simultaneity of the change of the flow rate and the compositional change of the gas in the measurement of mass emission.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an apparatus for measuring the amount of emission of components that may cause environmental pollution such as exhaust gas from automobiles, and relates to the field of environmental technology.

[0002]

2. Description of the Related Art A CVS device has been widely used as a device for measuring the emission of components that may cause environmental pollution from an automobile, and the emission during a certain operation mode or operation time has been obtained. This method utilizes the fact that the exhaust gas is diluted with clean air to prevent condensation and has a constant flow rate, and that the component concentration of the diluted exhaust gas is proportional to the emission amount.

[0003]

2. Description of the Related Art In the conventional CVS method, when the exhaust gas purification technology for automobiles has advanced and the emission concentration of environmental pollutants has become extremely low, the background concentration of a large amount of air used for dilution decreases the dilution exhaust gas. There is a big problem that the concentration is close to that and accurate measurement is no longer possible. Furthermore, the conventional method has a drawback that it is not possible to analyze a detailed emission amount of a technically important fine operation mode.

[0004]

[Means for Solving the Problems] It is obvious that the emission amount can be easily obtained by multiplying the exhaust gas flow rate of the automobile by the concentration of the pollutant contained therein, but actually, the measurement of the exhaust gas flow rate is difficult. A practical device has not been developed due to technical difficulty or insufficient response of gas analysis. However, recently, an exhaust gas flowmeter of 0.1
Except for the gas sampling system, the main unit detection unit is also used as a device or exhaust gas analyzer that can measure with a response within seconds.
Responsiveness of about one second is becoming possible.

[0005] When the component emission amount is obtained from the direct measurement of the flow rate and the component concentration of the exhaust gas, since the exhaust gas flow rate and the component also change in accordance with the change of the operation state, the synchronism within about 0.2 seconds is required. In this case, the actual emission value may be different from the actual emission value. In this connection, it is necessary to correct the measured value, particularly the gas analysis value, over time. This also applies to a stage where high-speed exhaust gas sampling is performed and then gas analysis is performed separately from the analysis of the exhaust gas. Normally, there is little delay in the exhaust gas flow measurement value, but the gas analysis value first flows out of the exhaust valve of the engine and then flows through various devices including the exhaust system muffler, and is exhausted from the tail pipe until it is exhausted from the tail pipe. You must pass the time to pass the route. Further, even after the gas is extracted, it takes a certain amount of time to reach the detection unit of the analyzer even if it is almost constant. By simply estimating these times from the inherent characteristics of the engine and the operating conditions and automatically correcting the time, it is possible to secure the synchronization.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention. Engine 3 of car 2 in FIG.
Is provided with an exhaust system from the exhaust manifold 4 to the tail pipe outlet 7 via the catalyst device 5 and the muffler 6. The volume of the exhaust system varies depending on the engine, but may be about 10 liters in a passenger car class.
Since the time during which the exhaust gas passes through the exhaust system is substantially constant in absolute pressure and volume, it is inversely proportional to the product of the actual flow velocity, that is, the product of the standard state reduced flow rate and its absolute temperature. Although there is almost no time lag in the flow measurement at the tail pipe outlet 7, it takes time for the actual exhaust gas to flow from the exhaust manifold 4 to the tail pipe outlet 7. This time can be obtained by various estimation methods, one of which is the time obtained by using the constant C relating to the dead volume of the exhaust system, the ratio of the standard state equivalent flow rate q, and the absolute temperature of the exhaust gas. C / [q (273 + t) / 273]. It is not impossible to simply estimate from the engine speed alone.

Although various types of exhaust gas flow rate measuring devices 10 are conceivable, in the case of high speed, the delay time of measurement is 0.1 second or less, and this delay time is not considered in comparison with the delay time of gas analysis values. Is also good. Extraction of a sample gas for exhaust gas composition analysis is performed at a constant flow rate from a probe 12 provided immediately after the exhaust gas flow rate measurement via a sample system 15 including a filter 13 and a pump 14. The delay time of the sample system usually varies depending on the flow rate, system length, dead volume, etc., but can be regarded as constant regardless of the operating conditions of the engine. Further, since the delay time in the gas analyzer 16 can be assumed to be constant, the delay of the analysis system including these is taken into consideration as a constant a in order to secure the simultaneousness of the exhaust gas flow measurement and the analysis value output. The calculation for ensuring the simultaneity is performed by the delay time calculation circuit 17 in which the flow rate signals q,
This is performed using the exhaust gas temperature signal t and the constant C, or using the engine speed signal N or the boost pressure signal Pi from the engine. As an arithmetic expression, τ = a + 273C / [q (27
3 + t)] or τ ′ = f (q) similar to this equation, or τ _N = a + 1.5 (N / 1000) ^−1.5 or τ _N ′ = f (N, Pi) similar to this equation. .

[0008] In the mass emission calculation circuit 18, the exhaust gas flow rate signal from the flow rate calculation circuit 11 and the gas analyzer 1
The product of the gas composition signal in the wet state from Step 6 and the signal corrected by the delay time calculation circuit 17 is obtained, and the instantaneous mass emission is displayed and output. Further, when the gas analysis was performed in dry conditions, following humidity correction factor to the drying gas concentration of the gas components [1 / {1+ (r / 4 ) (C0 2 + C
O) The gas composition signal is input to the mass emission arithmetic circuit 18 by using the humidity correction arithmetic circuit 19 for multiplying the concentration by multiplying by [｝] to convert the concentration into the wet state. Mass emission calculation circuit 1
Numeral 8 not only displays and outputs, for example, mg / 0.2 sec as an instantaneous emission value, but also can display and output an integrated emission value in any required time or operation mode.

Flow rate calculation circuit 11 and delay time calculation circuit 17
Since the time relationship between the time and the mass emission calculation circuit 18 is delayed on the gas analysis side, the mass emission is actually calculated by delaying the measured flow value by the delay time. The flow rate calculation circuit 1 including the humidity correction calculation circuit 19
1, the delay time calculation circuit 17, the mass emission calculation circuit 18, and the like can be combined into a single panel to form the calculation device 20.

Similar time correction can be applied not only to continuous gas analysis but also to a case where high-speed gas sampling is performed and gas analysis is performed later. In this case, a fixed time delay a of the analyzer is required.
May be set to zero, and the delay caused by other dead volume of the exhaust system may be corrected.

[0011]

According to the present invention, the measurement of the exhaust gas flow rate and the gas analysis can be performed without using a large-sized and large-energy-consuming apparatus such as a conventional CVS apparatus in measuring the mass emission of automobile exhaust gas. Can be obtained at the same time, and accurate emissions can be obtained. There is no room for errors such as contamination components caused by dilution air, and it is suitable for measuring mass emission of low-emission vehicles. In addition, emission measurement for the operation mode can be performed with a short time resolution, so that not only measurement of total emission but also detailed analytical evaluation of emission values is possible, and emission value measurement and evaluation at the development stage can be performed almost in real time. effective.

[0012]

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a simultaneousness correction device that secures simultaneousness in mass emission measurement by high-speed continuous measurement of an exhaust gas flow rate and a gas composition.

[Explanation of symbols]

 2 Automobile 3 Engine 4 Exhaust manifold 5 Catalytic device 6 Muffler 7 Outlet 8 Duct 9 Duct 10 Exhaust gas flow measuring device 11 Flow calculating circuit 12 Probe 13 Filter 14 Pump 15 Sample system 16 Gas analyzer 17 Delay time calculating circuit 18 Mass emission calculating Circuit 19 Humidity correction arithmetic circuit

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[Procedure amendment]

[Submission date] September 12, 2001 (2001.9.1)
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Patent application title: Simultaneity correction device for ensuring simultaneousness in mass emission or fuel consumption measurement by high-speed continuous measurement of exhaust gas flow rate and gas composition

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010] The time correction for ensuring the simultaneity is based on the exhaust gas.
Calculate and calculate fuel consumption from flow meter and exhaust gas analysis
Especially important in the case of
Compensation for gas analysis value lagging flow measurement value
And the approach is exactly the same. Similar time correction can be applied not only to continuous gas analysis but also to a case where high-speed gas sampling is performed and gas analysis is performed later. In this case, the fixed time delay a of the analyzer may be zero, and other exhaust systems may be used. May be corrected for the delay caused by the dead volume.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

[0011]

According to the present invention, the measurement of the exhaust gas flow rate and the gas analysis can be performed without using a large-sized and large energy-consuming device such as a conventional CVS device in measuring the mass emission of automobile exhaust gas. Can be obtained at the same time, and accurate emissions can be obtained. It has no room for errors such as contamination components caused by dilution air, and is suitable for mass emission measurement of low-emission vehicles. In addition, the measurement of emissions for the operation mode can be performed with a short time resolution, so that not only the measurement of the total emissions but also a detailed analytical evaluation of the emission values is possible. effective. Ma
Also, from the exhaust gas analysis and the exhaust gas flow measurement, the H / C
To calculate the instantaneous fuel consumption by calculating
It is especially important to ensure timeliness,
Measuring and calculating fuel consumption for about 0.2 seconds
Can be done.

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Claims (3)

[Claims] An exhaust gas mass emission of a vehicle is continuously measured at an outlet of an exhaust pipe using a high-speed response exhaust gas flow meter and a high-speed response gas analyzer, or gas is analyzed by performing high-speed gas sampling. In an apparatus for calculating and calculating the instantaneous mass emission by converting the mass concentration and the mass flow rate, the total delay time τ of the gas analysis value with respect to the flow rate measurement value is calculated as a standard state conversion exhaust gas flow rate measurement value q. Using the exhaust gas temperature measurement value t, a constant C corresponding to the dead volume of the exhaust system, and a fixed delay time a for the exhaust gas analysis system, etc., the following arithmetic expression or a calculation similar to this expression is used. Having an arithmetic circuit for automatically correcting the time for the change in the exhaust gas composition,
Simultaneity correction device that ensures the simultaneousity of flow rate change and gas composition change in mass emission measurement. τ = a + 273C / [q (273 + t)] 2. Mass emission of automobile exhaust gas is continuously measured at the outlet of an exhaust pipe using a high-speed response exhaust gas flow meter and a high-speed response gas analyzer, or gas analysis is performed by performing high-speed gas sampling. In an apparatus for calculating and calculating an instantaneous mass emission by converting into a mass concentration and a mass flow rate, an exhaust gas analysis system or the like is added with a fixed delay time a and a delay time due to gas accumulation in the exhaust system. For the delay time τ, there is an arithmetic circuit for automatically correcting the time for the change in the exhaust gas composition based on the following equation or a calculation similar to this equation as a function of the engine speed N (rpm) extremely simply. And a device that ensures synchronization in mass emission measurement. τ = a + 1.5 (N / 1000) ^-1.5 3. An H / C value r of fuel (normally r is about 1.75) when gas analysis is performed on dry exhaust gas in the apparatus for calculating and calculating mass emission according to claim 1 or 2. The moisture in the exhaust gas is estimated from the analysis values of the volume concentration of CO ₂ and CO in the dry gas, and the humidity correction coefficient [1 / ｛1+ (r / 4) (C0
₂ + CO)｝], and automatically converts the concentration into a wet state to obtain the mass emission directly from the product of the component ratio of the exhaust gas and the flow rate. Has an arithmetic circuit that automatically corrects,
A device that ensures synchronization in mass emission measurement.