JPS59192858A - Canister purge controlling apparatus - Google Patents

Abstract

PURPOSE:To enable to achieve optimum purge control according to the operational conditions of an engine, by effecting purging of fuel vapor stored in a canister by calculating an optimum purge quantity through detection of the water temperature, opening of a throttle valve, intake pressure, etc. for judging the quantity of intake air and the operational conditions of engine. CONSTITUTION:In operation of an engine, a basic purge quantity is calculated at a control circuit 13 on the basis of the output signal of an air-flow meter 9 representing the quantity of intake air. In case that the engine temperature is judged to be low from the output signal of a water-temperature sensor 10, purging of fuel vapor is stopped. At the time of high-load operation of the engine, purging of fuel vapor is also stopped in response to a signal representing the throttle opening or the output signal of a boost sensor 11 representing the intake pressure. Further, purge is also stopped for change in the air-fuel ratio detected from the output signal of an O2-sensor 12, and the purge quantity is corrected to a value not to affect the air-fuel ratio through detection of the air-fuel ratio. Thus, a variable displacement pump 8 is operated in response to the output signal of the control circuit 13, and fuel vapor in a canister 5 is purged to the intake system according to the quantity of intake air.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a canister purge control device incorporated into a fuel evaporative emission control device in a vehicle internal combustion engine.
In particular, it relates to optimal purge control in relation to engine operating conditions.

According to the charcoal canister method of fuel vapor gas emission control devices, the fuel vapor generated in the fuel tank, etc. at high temperatures is temporarily adsorbed and stored in a canister, and is then purged from this canister into the engine intake system along with the outside air. In this case, the purge device is, for example, the
As shown in Japanese Patent No. 90923, purging is performed in a relatively low load range by boat negative pressure depending on the trace of the throttle valve.

By the way, when the purge is controlled by the bow 1 negative pressure of the throttle valve, the purge is performed even when the operating state is unstable such as when the engine is cold, and this may deteriorate the drivability. In addition, in an internal combustion engine where the air-fuel ratio is controlled by the signal from the 02 sensor, the air-fuel ratio will fluctuate if you purge improperly.
In a supercharged internal combustion engine, the boat negative pressure becomes positive pressure during supercharging, causing problems such as being unable to purge, and the above-mentioned prior art method cannot be applied.

In view of these circumstances, the present invention performs electronically optimal purge control according to the engine operating state, and is applicable even when special air-fuel ratio control, supercharging, etc. are performed. The purpose is to provide equipment.

For this purpose, the device according to the present invention detects the water temperature, throttle opening, intake pressure, etc. in order to determine whether intake air is available and the engine operating state, and uses these detection signals to calculate the optimal purge by the control circuit. Based on this, it is recommended that the variable flow fil pump purges the 31st steam stored in the cylinder.

Hereinafter, one embodiment of the present invention will be described quantitatively with reference to the drawings. In one drawing, 65 are shown, 1 is the engine body, 2 is the carburetor, 3 is the intake manifold, 4 is the 111 whistle, and 5 is the Moe 1
This is a canister that communicates with a tank or the like and adsorbs fuel vapor.In the case of a non-turbo car, the purge line 6 from the kitnister 5 is connected to the downstream side of the valve 7 as shown in the figure, and is connected to the downstream side of the valve 7 in the case of a turbo car. In this case, the purge line G is connected to the upstream side of the supercharger, and there is a sitot valve f'l in this purge line G.
A pump 8 is installed as a control system. On the other hand, the amount of intake air measured by the near flow meter 9, which is installed upstream of the vaporizer 2 as a control system, and the amount of intake air detected by the water temperature sensor 9"10 are The intake pressure detected by the boost pincer 11 on the downstream side of the throttle valve 7, the throttle opening according to the throttle valve 7, and the signal from the exhaust system 12 are input to the control circuit 13. A circuit 11'I'1 is configured to drive the variable flow closed pump 8 based on the purge command number from the control circuit 13. A substantially proportional purge map is stored and applied to each operating state to further control the purge.

With this configuration, the control circuit 1 is controlled based on the intake air amount signal from the upper aflow meter 9 during engine operation.
3, the basic purge ii'i /J'X is shut out, and in contrast, the water temperature of the water temperature sensor 9-10 (rj Booth 1 - Intake pressure of sensor 11 (No. 8 sets the high negative value to '1' and purge is started. The signal from 02 and 12/rsl indicates that the air-fuel ratio changes and the air-fuel ratio changes to '1'. Then, the air-fuel ratio is sensed η1 and the purge is corrected to a level that does not damage the air-fuel ratio.In this way, the control circuit 13 outputs the purge command signal as a result of various judgments. Yamahenryukan pump 8 is driven, IL '7
At 8 o'clock when P + luck φ, the fuel IfA stored in the canister 5 and -C is purged into the intake system according to the amount of intake air.

As is clear from the above description, according to the present invention, intake air m, water temperature, throttle opening, intake pressure, ()z't?
Since the purge (2) is controlled 211 by each signal from the air conditioner, etc., optimal purge control can be performed without impairing drivability or air-fuel ratio. Furthermore, it is possible to apply J5 in relation to leakage in cases where a supercharger, an EGl is installed, and the air-fuel ratio is controlled.

[Brief explanation of the drawing]

The drawing is a block diagram of an embodiment of the device according to the present invention. 5... Canister, 6... Purge line, 7...
1) Valve, 8... Variable flow rate pump, 9...
Airf I"-Meter, 10...Water temperature sensor, 11...
・Boost sensor 1.12・, 0□Senna, 12・
...Control circuit.

Claims (1)

[Claims] A shut-off buoy 4 variable flow in pump is installed in the purge line from the canister, and the control circuit calculates the purge amount according to each operating condition during normal operation based on signals such as intake air, water temperature, throttle pressure, and intake pressure. A canister purge control device, characterized in that it is configured to block the purge command signal from the control circuit and drive the above-mentioned variable A≧quantity pump to perform purge control.