JPH0466763A - Fuel vapor gas purge system - Google Patents

Abstract

PURPOSE:To calculate the gas amount flowing in an engine accurately by providing a gas adsorbed amount detecting mechanism to a vaporing gas adsorption device, and measuring the temperature of the air flowing in the purge, the pressure at the purge gas inflow port of the engine, and the inflow air amount. CONSTITUTION:In a vaporing gas adsorption device 3, electrodes 344 and 345 provided oppositely are connected to a control circuit 371 through lead wires 346 and 347, in a chamber full of an adsorbent 36. And in the control circuit 371, the adsorbed amount of the vaporing gas is measured by the voltage variation generated between the other opposite two poles of a bridge circuit following the variation of the resistance Rx between a pair of electrodes. In this case, the gas amount flowing in the engine 1 when a purge control valve 5 is opened is determined by the above adsorbed amount of the adsorbent 36, the temperature of the air flowing in the purge time, and the inflow air amount, in the ECU, while the pressure in a maniford 11 to be purged is measured by a pressure sensor 15, and the temperature of the inflow air is measured by a temperature sensor 7, to calculate the gas amount.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel evaporative gas purging system for adsorbing and purging evaporative gas from fuel in a fuel tank of an automobile or the like.

[Conventional technology]

2. Description of the Related Art Conventionally, automobiles have been equipped with an evaporative gas adsorption device to prevent fuel atrophy gas in a fuel tank from being released into the atmosphere, and the device controls adsorption and purging of gas in accordance with engine operation.

[Problems to be Solved by the Invention] Since the conventional fuel evaporative gas adsorption device is configured as described above, the amount of evaporative gas is not measured, and in particular, it is not possible to measure the amount of evaporative gas being purged during purging. I don't understand it at all. Incidentally, in recent years, demands for environmental purification have become stricter, and exhaust gas regulations have become increasingly strict. For this reason, even in a purge system, it is necessary to know the amount of gas to be purged.

This invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a fuel ejection gas purge system that can accurately measure the amount of evaporative gas entering an engine.

[Means for Solving the Problems] A fuel evaporative gas purge system according to the present invention has at least an inlet, an exhaust port, a purge port, and a chamber filled with an adsorbent for adsorbing evaporative gas, evaporated gas adsorption means having a detection means for detecting the amount of adsorbed gas;
The system is equipped with a purge means for purging adsorbed gas, a pressure detecting means for detecting the pressure of the purge gas discharge part of the purge means, and an intake temperature detecting means for detecting the temperature of the air flowing in when purging the adsorbed gas, and the amount of purge gas at the time of purging can be determined. It is characterized by measuring.

[Function] The fuel evaporative gas purge system of the present invention measures the temperature of the air flowing in during purging, and also measures the pressure at the purge gas inlet of the engine to measure the amount of air flowing in.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a configuration diagram of a fuel evaporative gas purge system according to the present invention, in which 1 is an engine of an automobile, 11 is a manifold of this engine 1, 12 is a throttle valve that adjusts the amount of intake air, 13 is an air flow meter, and 14 is an air flow meter that controls outside air. The air cleaner 15 to be introduced is a pressure sensor that detects the pressure inside the manifold 11. On the other hand, 2 is a fuel tank, 3 is a fuel evaporative gas adsorption device, 4 is a check valve installed in the pipe between the fuel tank 2 and the evaporative gas adsorption device 3, 5 is a purge control valve for controlling the amount of purge, 6 is an engine control unit, and 7 is an intake temperature sensor. Also, 3
21 is an exhaust port of the evaporative gas adsorption device 3, 331 is an inlet port, 332 is a persillo, and 371 is a control circuit.

FIG. 2 shows a detailed configuration diagram of the evaporative gas adsorption device 3. In the figure, a case 32 having an exhaust port 321 to the atmosphere at the bottom, an evaporative gas inlet 331, and a persillo 33 are shown.
A partition plate 34 having a plurality of flow holes 341 on the lower side and a partition plate 35 having a plurality of flow holes 351 on the upper side are provided in the chamber sealed with a cap 33 having a cap 2.
Both partition plates 34 and 35 separate chambers A, BC, and
D is formed. Chamber A communicates with inlet 331, chamber B communicates with persillo 332, chamber communicates with outlet 321, and chamber C communicates with chamber ABD by means of flow holes 341, 351, respectively.

Further, in the chamber C, there is a holding portion 342 formed on the partition plate 34.
Electrodes 344 and 345 are installed opposite to 343, and an adsorbent 36 made of activated carbon is filled in the chamber C. The intake temperature sensor 7 is provided at the exhaust port 321. The electrode 344345 is connected to a control circuit 371 provided outside the case 32 via lead wires 346 and 347.

37 is a package containing a control circuit 371;
is a grommet for drawing out the lead wires 346 and 347, and 373 is an external lead terminal.

FIG. 3 shows an example of the control circuit 371, which detects changes in the electrical resistance R between the electrodes 344 and 345, where r, ``-r'' are bridge resistance circuits, and VCC is the power supply voltage. 4 shows an equivalent circuit when the capacitance between the electrodes 344° and 345 is C.

Next, the operation will be explained. When the amount of evaporated gas increases and the pressure inside the fuel tank 2 increases, the evaporated gas in the fuel tank 2 is discharged from the suction boat 331 to the chamber A via the check valve 4.
It flows into the chamber C through the circulation hole 351. Here, the evaporated gas is adsorbed by the adsorbent 36, and only air enters the room through the direct hole 341 and is discharged into the atmosphere from the exhaust port 321. In addition, when the purge conditions for the engine 1 are established, the gas adsorbed by the adsorbent 36 along with the air flowing in from the exhaust port 321 separates again and passes through the chamber B from the persillo 332 to the manifold 11 side of the engine 1. The air is sucked into the engine 1 together with the air that is discharged from the air cleaner 14 and flows in through the air flow meter 13 and the throttle valve 12.

Now, the adsorption and desorption of vaporized gas by the adsorbent 36 is as follows.
6, such as electrical conductivity and dielectric constant.

Therefore, the resistance value RX and capacitance value CX between the electrodes 344 and 345 provided in the chamber C will also change due to the adsorption and desorption of gas.
．． A power supply voltage (■) is applied between two opposing poles of a bridge circuit formed by the resistor R8 between 345 and 345 as one side of the bridge, and the other three sides as fixed resistors r1 to r. , a voltage is generated between the other two opposing poles of the bridge circuit as the resistance RX changes. This voltage change makes it possible to measure the adsorption amount of evaporated gas.

The above has described a measurement method that utilizes the fact that the electrical characteristics change depending on the adsorption amount of the adsorbent 36 provided in the evaporative gas adsorption device 3. However, as another detection method, as shown in FIG. A similar effect can be obtained by utilizing the temperature change caused by the gas in the temperature sensor 38 buried in the temperature sensor 36 .

The amount of gas flowing into the engine 1 when the purge control pulp 5 is opened is determined by the adsorption amount of the adsorbent 36, the temperature of the air flowing during purging, and the amount of air flowing. Therefore, if the pressure of the manifold 11 to be purged is measured by the pressure sensor 15 and the temperature of the incoming air is measured by the temperature sensor 7, the gas amount will be determined from the following equation.

GPcX: Q, S (T,) = 1T block]--S P
S (T,) where G is the purge gas amount, Q is the purge air amount, P is the atmospheric pressure, Pl is the manifold pressure, T
1 incoming air temperature, SP is the purge passage cross-sectional area.

[Effects of the Invention] As explained above, according to the present invention, the evaporated gas adsorption device is provided with a gas adsorption amount detection mechanism, and the temperature of the air flowing in during purging is measured, and the pressure at the purge gas inlet of the engine is measured. Since the amount of air flowing into the engine is measured, the amount of gas flowing into the engine can be accurately determined.

[Brief explanation of drawings]

The first part is a configuration diagram of a fuel evaporative gas purge system according to an embodiment of the present invention, FIG. 2 is a sectional view of an evaporative gas adsorption device, FIG. 3 is a control circuit diagram for detecting the amount of adsorption, and FIG. 4 is a diagram of another example. FIG. 5 is a diagram illustrating another method of detecting the amount of adsorption. DESCRIPTION OF SYMBOLS 1... Engine, 2... Fuel tank, 3... Capsule gas adsorption device, 5... Purge control valve, 6...
・Engine control unit, 7... Intake temperature sensor, 12... Throttle valve, 15... Pressure sensor, 32]... Exhaust port, 331... Intake port, 332
... Persil, 36... Adsorbent, 371... Control circuit, AC, D... Chamber. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] an evaporated gas adsorption means having at least an inlet, an outlet, a purge port, a chamber filled with an adsorbent for adsorbing evaporated gas, and a detection means for detecting the amount of gas adsorbed by the adsorbent; A purge means for purging, a pressure detection means for detecting the pressure of a purge gas discharge part of the purge means, and an intake air temperature detection means for detecting the temperature of air flowing in during adsorption gas purging, and measuring the amount of purge gas during purging. A fuel evaporative gas purge system featuring: