JPH08327524A - Hydrocarbon adsorbing and desorbing performance evaluation device for canister - Google Patents

Abstract

PURPOSE: To concurrently find the volume of each hydrocarbon adsorbed to or desorbed from a canister and discharged without being adsorbed or desorbed, by measuring the weight change of a test canister under the circulation of test gas, keeping an exhaust fluid at a constant pressure, introducing the test gas into volumetrically measurable sealed space for continuously measuring the concentration of hydrocarbon in the space, regarding the test of the hydrocarbon adsorbing and desorbing performance of a vehicular canister. CONSTITUTION: A fluid with or without hydrocarbon contained is made to flow across a canister 1 for evaluating the performance thereof. In this case, the weight change of the canister 1 is continuously measured, and outgoing fluid within a constant volume is introduced into isolated space 24 capable of a volumetric change at a small differential pressure. Then, the concentration of hydrocarbon therein is continuously measured. In addition, the volume of outgoing hydrocarbon is continuously obtained from the flowrate of a sample consumed for the measurement as well as the volumetric change of the space 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a canister hydrocarbon adsorption / desorption performance evaluation device used as an environmental measure for an automobile, and is used in the automobile industry, petroleum industry and environmental industry.

[0002]

2. Description of the Related Art As a method for testing the hydrocarbon adsorption / desorption performance of a canister such as activated carbon used to prevent the evaporation of hydrocarbons from an automobile fuel system, butane gas and pure air or pure nitrogen are passed through the canister. hand,
The method of measuring the weight change of a canister has been widely adopted.

[0003]

The hydrocarbons that may evaporate from an automobile are not pure butane used in conventional performance tests but are a mixture of many kinds of hydrocarbons such as gasoline. There is a possibility that the performance may not always match the performance during use. In particular, it has become necessary to evaluate the performance of the canister when the fuel tank is actually refueled due to stricter emission regulations, but it was difficult to cope with this with the conventional technology.

The hydrocarbons that evaporate from the fuel system when the vehicle is refueled with gasoline or when the engine is stopped are propane and butane, which are extremely small, and pentane, hexane and higher hydrocarbons in a vaporized state having a large C number. The concentration is different from pure butane 100%, and the mixture is 1% or less in air. The adsorption / desorption performance of a canister such as activated carbon for hydrocarbons having such complicated components is complicated, and it is difficult to perform desorption within a short time and perform performance measurement under the same initial test conditions. In particular, it is a subject to clarify the hydrocarbon desorption conditions so that the adsorption / desorption performance test can be carried out under a certain desorption condition, and to construct a device capable of performing a test with a practical fuel evaporation component with good reproducibility.

[0005]

In response to this problem, the canister hydrocarbon adsorption / desorption performance evaluation device of the present invention is
In a device that tests the adsorption and desorption performance of hydrocarbons in automobile canisters, while measuring the weight change of the test canister while flowing the test gas, keep the discharged fluid at a constant pressure and measure the volume. The amount of hydrocarbons adsorbed and desorbed by the canister and the amount of hydrocarbons exhausted without being desorbed or adsorbed onto the canister can be simultaneously determined by introducing into the above space and continuously measuring the hydrocarbon concentration in that space.

[0006]

In the present invention, the amount of hydrocarbons desorbed when pure air or pure nitrogen is flown through the canister at a constant flow rate is accurately measured, and the canister under constant temperature / pressure and pure air flow rate conditions is used as the initial condition of the test. The amount of hydrocarbons desorbed in the canister must be kept within the required conditions, and the amount of hydrocarbons that are desorbed or not adsorbed during the adsorption process must be accurately measured to determine the amount of hydrocarbons in the canister for the inflow gas with varying concentrations. The means to clearly grasp the adsorption / desorption characteristics was adopted. That is, the outflow side of the canister is used as a single flow path, which is maintained under conditions almost the same as atmospheric pressure, and is led to a space where its volume and change can be measured, and the hydrocarbon concentration in that space is continuously measured. The method of determining the amount of hydrocarbons flowing out of the canister was used. With this measuring method, the adsorption / desorption characteristics of the canister can be ascertained in a correlated manner together with the continuous weight measurement of the canister during the test.

[0007]

EXAMPLE An example of the present invention will be described with reference to FIG. In FIG. 1, 100 is a hydrocarbon adsorption / desorption performance evaluation device for a canister, and a hydrocarbon adsorption / desorption performance evaluation device 100 for a canister is a fuel tank 23, a pure butane gas cylinder 20, and a pure butane gas cylinder 20 on the inlet side of the canister 1 to be evaluated. The air cylinder 29 is connected, and the container 30 continues on the outlet side of the canister 1. Inlet side entrance 11 of canister 1
Is connected to the flow meter 17 via the flexible tube 14, and the outlet side is connected to the outlet 12 with the flexible tube 15 with one outlet, and the pressure gauge 18 is sufficient to measure the pressure. It is connected to a container 30 having a volume. Canister 1
The weight of is continuously measured by the balance 51. The inside of the container 30 is divided into two spaces by a diaphragm 32 supported by a ventilation member 33 such as a lattice so that the pressure difference is small enough to be ignored. One of the spaces is a measurement space 34, and the measurement space 34 is the canister 1 And the internal gas is always sufficiently homogenized by the stirring fan 31, and the sample gas is flown to the flowmeter 40.
The hydrocarbon concentration is continuously measured by the gas analyzer 41 while being measured. When the gas analyzer 41 does not alter or consume the sample gas, it can be circulated to the measurement space 34 via the reflux passage 42. The change in the volume of the measurement space 34 is caused by the change in the volume of the space 55 on the opposite side of the measurement space 34 of the container 30 having a constant volume separated by the diaphragm 32 from the gas meter 35.
Measure by measuring at. Further, the gas in the space 55 on the opposite side of the measurement space 34 can be discharged and ventilated by operating the pump 37 and the solenoid valves 19, 36, 38 during non-measurement.

With the above apparatus, a sufficient amount of pure air is made to flow from the pure air cylinder 29 through the pressure reducing valve 28 and the three-way solenoid valve 16 to the canister 1 to keep the initial condition constant, for example, from the pure butane gas cylinder 20. Via the pressure reducing valve 21 and the three-way solenoid valves 22 and 16, butane gas is adsorbed to the canister 1 to measure its weight change, and at the same time, the change in the hydrocarbon concentration in the measurement space 34 and its volume change are measured, It is possible to measure the non-adsorbed amount of butane that is not adsorbed by the canister 1 under atmospheric pressure conditions. Further, even when gasoline is supplied to the fuel tank 23, when the fuel flow 25 is introduced from the gasoline injector 26, the gas containing the fuel vapor is discharged from the space 24 in the tank by the three-way solenoid valve 22,
It is measured by flowing into the canister 1 via 16 as in the case of butane gas. At this time, the concentration and composition of the inflowing hydrocarbon are unknown. However, even in this case, the weight change of the canister 1 and the canister 1
The amount of hydrocarbons flowing out of the is measured. That is, the hydrocarbon concentration in the outflowing gas is measured by the gas analyzer 41, and the flow rate thereof is measured from the volume change of the flow meter 40 and the measurement space 34 to obtain the hydrocarbon amount. The flow rate of the gas flowing into the canister is measured by the flow meter 17, the weight change of the canister is measured by the balance 51, and the hydrocarbon flowing out of the canister 1 is measured by the gas analyzer 41, the flow meter 40, and the gas meter 35, respectively, and calculated by the computer 52. Acquisition process,
The adsorption characteristics of the fuel vapor of the canister 1 can be displayed. After a certain period of time, the three-way solenoid valve 16
The canister 1 can be purged with pure air by switching between the above and other conditions, and the hydrocarbon desorption characteristics of the canister can be measured and displayed. Further, the initial test for the next adsorption test may be set to a prescribed condition, and the repeated test may be performed.

[0009]

As described above, according to the present invention, the amount of hydrocarbons flowing out from the canister can be relatively determined from the volume change of the measurement space 34 in a container having a constant volume and the hydrocarbon concentration in the gas in the space. It can be measured by a small and simple device.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of a hydrocarbon adsorption / desorption performance evaluation device for a canister.

[Explanation of symbols]

 1 Canister 11 Inlet Side Inlet 12 Outlet Port 14 Flexible Tube 15 Flexible Tube 16 3 Way Electromagnetic 17 Flowmeter 18 Pressure Gauge 19 Solenoid Valve 20 Pure Butane Gas Cylinder 21 Pressure Reduction Valve 22 3 Way Solenoid Valve 23 Fuel Tank 24 Space 25 Fuel flow 26 Gasoline injector 28 Pressure reducing valve 29 Pure air cylinder 30 Container 31 Stirring fan 32 Diaphragm 33 Ventilation member 34 Measuring space 35 Gas meter 36 Solenoid valve 37 Pump 38 Solenoid valve 40 Flowmeter 41 Gas analyzer 42 Reflux path 51 Balance 52 Calculation 55 Space on opposite side 100 Hydrocarbon adsorption / desorption performance evaluation device for canister

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[Procedure amendment]

[Submission date] July 12, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

EXAMPLE An example of the present invention will be described with reference to FIG. In FIG. 1, 100 is a hydrocarbon adsorption / desorption performance evaluation device for a canister, and a hydrocarbon adsorption / desorption performance evaluation device 100 for a canister is a fuel tank 23, a pure butane gas cylinder 20, and a pure butane gas cylinder 20 on the inlet side of the canister 1 to be evaluated. air cylinder 29 is connected, also the container 30 connect the outlet side of the canister 1. Inlet side entrance 11 of canister 1
Is connected to the flow meter 17 via the flexible tube 14, and the outlet side is connected to the outlet 12 with the flexible tube 15 with one outlet, and the pressure gauge 18 is sufficient to measure the pressure. It is connected to a container 30 having a volume. Canister 1
The weight of is continuously measured by the balance 51. The inside of the container 30 is divided into two spaces by a diaphragm 32 supported by a ventilation member 33 such as a lattice so that the pressure difference is small enough to be ignored. One of the spaces is a measurement space 34, and the measurement space 34 is the canister 1 And the internal gas is always sufficiently homogenized by the stirring fan 31, and the sample gas is flown to the flowmeter 40.
The hydrocarbon concentration is continuously measured by the gas analyzer 41 while being measured. When the gas analyzer 41 does not alter or consume the sample gas, it can be circulated to the measurement space 34 via the reflux passage 42. The change in the volume of the measurement space 34 is caused by the change in the volume of the space 55 on the opposite side of the measurement space 34 of the container 30 having a constant volume separated by the diaphragm 32 from the gas meter 35.
Measure by measuring at. Further, the gas in the space 55 on the opposite side of the measurement space 34 can be discharged and ventilated by operating the pump 37 and the solenoid valves 19, 36, 38 during non-measurement.

Claims (1)

[Claims] 1. A device for evaluating the performance of a canister, which is characterized by allowing a fluid containing a hydrocarbon or a fluid not containing a hydrocarbon to pass through the canister and continuously measuring the weight change of the canister, and measuring the fluid flowing out from the canister. In a certain volume, it leads to an isolated space where its volume can be changed with a small pressure difference, and the hydrocarbon concentration in that space is continuously measured, and the flow rate of the sample consumed for concentration measurement and the isolated space An apparatus for evaluating hydrocarbon adsorption / desorption performance of a canister, characterized in that the amount of hydrocarbons flowing out from the canister is continuously obtained from the volume change amount to evaluate the hydrocarbon adsorption / desorption performance of the canister.