JP3511539B2 - Hydrocarbon adsorption / desorption performance evaluation device for canister - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an apparatus for evaluating the performance of adsorption and desorption of hydrocarbons of a canister used as an environmental measure for automobiles, and more particularly to an automobile industry, an oil industry and an environmental industry. Used in the field. 2. Description of the Related Art As a method for testing the hydrocarbon adsorbing and desorbing performance of a canister such as an activated carbon used to prevent the evaporation of hydrocarbons from a fuel system of an automobile or the like, butane gas and pure air or pure nitrogen are used. Distributed to
Methods for measuring canister weight changes have been widely adopted. [0003] Hydrocarbons that may evaporate from automobiles are not pure butane used in conventional performance tests but are mixtures of various hydrocarbons such as gasoline. May not always match the performance in actual use. In particular, emission regulations have been tightened, and it has become necessary to evaluate the performance of the canister when actually refueling the fuel tank. [0004] Hydrocarbons that evaporate from the conditions at the time of refueling automobile gasoline and from the fuel system when the engine is stopped are extremely low in propane and butane, pentane, hexane and other hydrocarbons in a vaporized state having a high C number. Concentrations are also different from pure butane 100% and are mixtures of less than 1% each in air. The absorption / desorption performance of canisters such as activated carbon for hydrocarbons having such complex components is complicated, and it is difficult to desorb and measure the performance under the same initial test conditions in a short time. In particular, it is an object of the present invention to clarify hydrocarbon desorption conditions so that an adsorption / desorption performance test can be performed under certain desorption conditions, and to configure an apparatus capable of performing a test with a practical fuel evaporation component with good reproducibility. [0005] In response to this problem, an apparatus for evaluating the adsorption and desorption of hydrocarbons of a canister according to the present invention comprises:
In a device for testing the adsorption and desorption performance of hydrocarbons of automobile canisters, while measuring the weight change of the test canister while circulating the test gas, the discharged fluid is kept at a constant pressure and the volume can be measured. The amount of hydrocarbons adsorbed to and desorbed from the canister and the amount of hydrocarbons discharged without being desorbed or adsorbed are simultaneously determined by continuously measuring the hydrocarbon concentration in the space. According to the present invention, the amount of hydrocarbon desorbed when pure air or pure nitrogen flows through the canister at a constant flow rate is accurately measured, and a constant temperature, pressure and pure air flow rate are set as initial conditions for the test. Under the conditions, the amount of hydrocarbon desorbed by the canister is set within the required conditions, and the amount of hydrocarbon desorbed or not adsorbed even during the adsorption process is accurately measured, and the canister for the inflow gas with a concentration change is measured. A means for clearly grasping the hydrocarbon adsorption / desorption characteristics of the above was adopted. That is, the outflow side of the canister is used as one flow path, which is maintained under almost the same conditions as the atmospheric pressure, led to a space where its volume and change can be measured, and the hydrocarbon concentration in that space is continuously measured. Then, a method of determining the amount of hydrocarbons flowing out of the canister was used. This measuring method can grasp the absorption and desorption characteristics of the canister in correlation with the continuous measurement of the weight of the canister during the test. An embodiment of the present invention will be described with reference to FIG. In FIG. 1, reference numeral 100 denotes a device for evaluating the hydrocarbon adsorbing / desorbing performance of a canister. The device 100 for evaluating the hydrocarbon adsorbing / desorbing performance of a canister has a fuel tank 23, a pure butane gas cylinder 20, and a pure butane gas cylinder 20 at 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 inlet 11 of canister 1
Is connected to a flow meter 17 via a flexible tube 14, and the outlet side is connected to the outlet 12 by a flexible tube 15 with one outlet, and sufficient pressure is measured by a pressure gauge 18 while measuring the pressure. It is connected to a container 30 having a volume. Canister 1
Is continuously measured by the balance 51. The interior of the container 30 is divided into two spaces by which a pressure difference is negligible by a diaphragm 32 supported by a ventilation member 33 such as a grid. One of the spaces is a measurement space 34, and the measurement space 34 is a canister 1. And the internal gas is always sufficiently homogenized by the stirring fan 31, and the sample gas is supplied to the flow meter 40.
The hydrocarbon concentration is continuously measured by the gas analyzer 41 while the measurement is performed in the step (1). When the gas analyzer 41 does not alter or consume the sample gas, the sample gas can be returned to the measurement space 34 via the reflux path 42. The change in the volume of the measurement space 34 is determined 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 fixed volume separated by the diaphragm 32.
Measured by measuring with. 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, and 38 when measurement is not performed. With the above-described apparatus, a sufficient amount of pure air is supplied from the pure air cylinder 29 to the canister 1 via the pressure reducing valve 28 and the three-way solenoid valve 16 to keep the initial conditions 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 and its weight change is measured. At the same time, the change in the hydrocarbon concentration in the measurement space 34 and the change in its volume are measured. The amount of non-adsorbed butane that is not adsorbed by the canister 1 under atmospheric pressure conditions can be measured. Further, even in the case of supplying gasoline to the fuel tank 23, when the fuel flow 25 is supplied from the gasoline injector 26, the gas containing the fuel vapor is supplied from the space 24 in the tank to the three-way solenoid valve 22,
16 and flows into the canister 1 as in the case of butane gas, and is measured. At this time, the concentration and composition of the inflowing hydrocarbon are unknown. However, also in this case, the weight change of the canister 1 and the canister 1
The amount of hydrocarbons flowing out of the system is measured. That is, the hydrocarbon concentration in the outflowing gas is measured by the gas analyzer 41, and the flow rate is measured from the volume change of the flow meter 40 and the measurement space 34 to obtain the amount of hydrocarbons. 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. Acquisition processing,
The adsorption characteristics of the canister 1 with respect to the fuel vapor can be displayed. After a certain period of time, the three-way solenoid valve 16
Is switched to purge the canister 1 with pure air, and the hydrocarbon desorption characteristics of the canister can be measured and displayed. Furthermore, a repetition test can be performed by setting the initial conditions for the next adsorption test to certain specified conditions. As described above, according to the present invention, the amount of hydrocarbon flowing out of the canister is determined from the change in the volume of the measurement space 34 in the vessel of a fixed volume and the hydrocarbon concentration in the gas in the space. Can be measured by a relatively small and simple device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a structural explanatory view of a hydrocarbon adsorbing / desorbing performance evaluation device for a canister [Description of symbols] 1 canister 11 inlet side inlet 12 outlet 14 flexible tube 15 flexible tube 16 3 Electromagnetic 17 Flow meter 18 Pressure gauge 19 Solenoid valve 20 Pure butane gas cylinder 21 Pressure reducing 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 Stirrer fan 32 Diaphragm 33 Ventilation member 34 Measurement space 35 Gas meter 36 Solenoid valve 37 Pump 38 Solenoid valve 40 Flow meter 41 Gas analyzer 42 Reflux path 51 Balance 52 Calculator 55 Space 100 on the other side 100 Apparatus for evaluating hydrocarbon adsorption / desorption performance of canister

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-101534 (JP, A) JP-A-6-108930 (JP, A) JP-A-6-173789 (JP, A) JP-A-6-173789 235355 (JP, A) JP-A-51-146276 (JP, A) JP-A-57-63431 (JP, A) JP-A-59-69140 (JP, A) JP-A-63-214643 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 5/00-5/04 G01M 15/00-17/06 F02M 25/00-25/14 F02B 47/00-49/00 JICST file (JOIS)

Claims (1)

(57) [Claims] [Claim 1] Passing a test gas through a canister
In the apparatus for evaluating the hydrocarbon adsorption / desorption performance of the canister , a constant flow of pure air or pure nitrogen is applied to the canister.
A constant temperature and
Canister under pressure and pure air or pure nitrogen flow conditions
Make sure that the star's hydrocarbon desorption is within the required conditions
In addition, while continuously changing the weight of the canister while passing the test gas through the canister, the volume of the fluid flowing out of the canister can be changed with a small differential pressure within a certain volume. , Almost the same conditions as atmospheric pressure
The canister is guided from the measured value of the continuous measurement of the hydrocarbon concentration in the space, the flow rate of the test gas consumed for the concentration measurement, and the volume change of the isolated space. Characterized in that the amount of hydrocarbons flowing out of the canister is continuously determined to evaluate the hydrocarbon adsorption / desorption performance of the canister.