JPH0537008Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to an evaporative fuel control device for a vehicle, and is particularly designed to control the flow of high-concentration evaporative fuel into the intake system when the fuel system temperature is above a predetermined temperature and during high-load operation. The present invention relates to an evaporative fuel control device for a vehicle that promotes purging efficiency of evaporated fuel by inhaling the evaporated fuel.

[Conventional technology]

In the past, evaporated fuel generated from the fuel tank, etc. when the engine was stopped was released directly into the atmosphere, causing air pollution. However, with the recent tightening of air pollution prevention regulations, a canister system has been adopted as a countermeasure. was developed. This canister system temporarily adsorbs evaporated fuel onto activated carbon (charcoal) inside the canister to prevent it from being released into the atmosphere.During operation, the evaporated fuel adsorbed on the canister is purged (separated) from the activated carbon. This method introduces it into the intake system and burns it.

An evaporative fuel control device using this canister method is disclosed in Japanese Patent Laid-Open No. 53-56416. According to this publication, the valve is configured to switch the vaporized fuel adsorbed by a valve during idling and deceleration from flow release to vacuum release, and purging is performed in accordance with the operating state.

[Problem that the invention attempts to solve]

By the way, in a conventional vehicular evaporative fuel control device, the evaporative fuel adsorbed by the canister is sucked into the engine using the engine's suction negative pressure.

Therefore, during high-load operation, the suction negative pressure becomes small, the amount of evaporated fuel sucked is small, and the purge efficiency is reduced.

Furthermore, during purging, atmospheric air is also sucked into the engine along with the evaporated fuel.

As a result, for example, when the fuel temperature is high, a large amount of evaporated fuel is generated within the fuel tank, and this large amount of evaporated fuel cannot be sufficiently purged.

[Purpose of invention]

Therefore, in order to eliminate the above-mentioned disadvantages, the purpose of this invention is to provide a temperature detection section that detects the fuel system temperature of the vehicle, a load detection section that detects during high load operation, and an atmospheric passage that opens to the atmosphere in the canister. When the fuel system temperature is above a predetermined temperature and the canister is operated under high load, the atmospheric passage is closed in the canister to prevent the intake of atmospheric air, and the intake system operates to draw only high-concentration evaporated fuel from the canister into the intake system. By installing a solenoid valve, it is possible to close the atmospheric passage of the canister when the fuel system temperature is above a predetermined temperature and during high-load operation, allowing high-concentration evaporated fuel to be drawn into the intake system, improving the efficiency of purging evaporated fuel. The object of the present invention is to realize a vehicle evaporative fuel control device that can be accelerated.

[Means for solving problems]

In order to achieve this object, this invention provides a temperature detection section for detecting the fuel system temperature of the vehicle in an evaporative fuel control device for a vehicle having a canister that adsorbs and holds evaporated fuel, and also detects when high load operation is being performed. A load detection section is provided, and the canister is provided with an atmospheric passage that is open to the atmosphere, and when the fuel system temperature of the vehicle is higher than a predetermined temperature and the vehicle is operated under high load, the atmospheric passage of the canister is closed and the atmospheric passage is opened to the atmosphere. The present invention is characterized in that a solenoid valve is provided that operates to prevent the intake of vaporized fuel from the canister and to allow only high-concentration evaporated fuel to be drawn from the canister into the intake system of the vehicle.

[Effect]

With the above configuration, when the fuel system temperature of the vehicle is above a predetermined temperature and the vehicle is operated under high load,
The atmospheric passage of the canister is closed by a solenoid valve installed in the middle of the atmospheric passage, preventing the intake of atmospheric air into the canister and allowing only high-concentration evaporated fuel to be sucked from the canister into the intake system, improving the purging efficiency of evaporated fuel. It is being promoted.

[Example] An example of this invention will be described in detail below based on the drawings.

The drawings show an embodiment of the invention. In the drawings, reference numeral 2 indicates an evaporative fuel control device of the vehicle, 4 indicates a carburetor, 6 indicates a throttle valve, 8 indicates an intake manifold, 10 indicates an intake passage, 12 indicates a canister, and 14 indicates an intake manifold.
is the fuel tank. A purge opening 18 of a purge passage 16 is provided in the intake passage 10 of the intake manifold 8.
is provided, and the intake passage 10 and the canister 12
are communicated with each other by a purge passage 16.

Further, the canister 12 and the fuel tank 14 are connected through an evaporative passage 20, and
The canister 12 is provided with an atmospheric passage 22 .

The fuel tank 14 is provided with a thermoswitch 24 serving as a temperature detection section for detecting the fuel system temperature, for example, the fuel temperature.

Further, the carburetor 4 is provided with a load detection section 26 that detects when it is operating under high load. This load detection section 26
More specifically, the load detection section 26 includes a switch lever 28 on the throttle valve 6 provided in the carburetor 4, and a throttle switch 30 that is turned on by the switch lever 28 during high load operation. .

A solenoid valve 32 is provided in the middle of the atmosphere passage 22 of the canister 12, and the thermoswitch 24 and the throttle switch 30 are connected to this solenoid valve 32, so that when the fuel temperature is above a predetermined temperature and the high load operation is performed, the atmosphere is removed. The passage 22 is configured to be closed by a solenoid valve 32.

Reference numeral 34 is an ignition switch, 36 is a battery, 38 is a two-way cap for the fuel tank 14, 40 is a fuel supply passage, and 42 is a fuel return passage.

Next, the effect will be explained.

When the fuel temperature of the vehicle is below a predetermined temperature and/or during operation other than under high load, the thermo switch 2
At least one of the throttle switch 4 and the throttle switch 30 is turned off, and the solenoid valve 32 is not energized. Therefore, the atmosphere passage 22 is opened, and the evaporated fuel and the atmosphere are transferred to the purge opening 1 of the purge passage 16.
8 into the intake passage 10.

Further, when the fuel temperature of the vehicle is above a predetermined temperature and the vehicle is operated under high load, the thermoswitch 24 and the throttle switch 30 are respectively turned on, and the solenoid valve 32 is energized. As a result, the atmospheric passage 22 is closed to prevent the intake of atmospheric air, and only vaporized fuel is sucked into the intake passage 10 through the purge opening 18 of the purge passage 16.

As a result, the atmospheric passage of the canister can be closed by the solenoid valve installed in the middle of the atmospheric passage, thereby preventing atmospheric air from being sucked into the canister and allowing only highly concentrated evaporated fuel to be sucked from the canister into the intake system. In this way, the purge efficiency of evaporated fuel can be promoted.

In addition, even when the vehicle operating state changes from high-load operation to idling, the solenoid valve is turned off and the atmospheric passage is opened, allowing atmospheric air to be introduced into the intake system and avoiding overload conditions during idling. It is possible and has practical advantages.

Further, even if the engine is stopped immediately after high-load operation, the solenoid valve is turned off and the atmosphere passage is opened, thereby introducing the atmosphere into the intake system and suppressing the pressure increase in the fuel tank.

Furthermore, the canister can be effectively purged under high-temperature, high-load operating conditions, making it possible to downsize the canister and contributing to cost reduction.

It should be noted that this invention is not limited to the above-mentioned embodiments, and can be modified in various ways.

For example, in the embodiment of this invention, a throttle switch that is turned on during high-load operation is provided as a load detection section for detecting high-load operation of the vehicle. A negative pressure switch that detects pressure and detects high load operation can also be used.

In addition, in the embodiment of this invention, a thermoswitch is provided as a temperature detection section for detecting the fuel system temperature, for example, the fuel temperature, but instead of this thermoswitch, an air temperature detection section for detecting the temperature inside the fuel tank is used. A thermoswitch can be used.

[Effect of idea]

As explained in detail above, according to this invention, a temperature detection section for detecting the fuel system temperature of the vehicle is provided, a load detection section is provided for detecting high load operation, an atmospheric passage is provided in the canister that opens to the atmosphere, An electromagnetic valve is provided in the atmospheric passageway that operates to close the atmospheric passage of the canister to prevent the intake of atmospheric air when the fuel system temperature is above a predetermined temperature and during high-load operation to allow only high-concentration evaporated fuel to be sucked from the canister into the intake system. With the provision of a This makes it possible to inhale only a concentrated amount of evaporated fuel, thereby promoting purging efficiency of the evaporated fuel. Furthermore, even if the operating state of the vehicle is changed from a high-load operating state to an idling operating state, an overload state during idling can be avoided, which is advantageous in practice.
Furthermore, even if the engine is stopped immediately after high-load operation, the increase in pressure within the fuel tank can be suppressed.
Furthermore, the canister can be effectively purged under high-temperature, high-load operating conditions, making it possible to downsize the canister.

[Brief explanation of the drawing]

The drawing is a schematic explanatory diagram of an evaporative fuel control system for a vehicle showing an embodiment of this invention. In the figure, 2 is an evaporated fuel control device, 4 is a carburetor, 6 is a throttle valve, 8 is an intake manifold, 10 is an intake passage, 12 is a canister, 14 is a fuel tank, 16 is a purge passage, 18 is a purge opening, 20 is an evaporative passage, 22 is an atmospheric passage, 24 is a thermo switch, 26 is a load detection section, 28 is a switch lever, 30 is a throttle switch, 32 is a solenoid valve, 34 is an ignition switch, 36 is a battery, 38 is 2 In the way type cap, 40 is a fuel supply passage, and 42 is a fuel return passage.

Claims (1)

[Claims for Utility Model Registration] 1. In a fuel vapor control device for a vehicle having a canister that adsorbs and holds vaporized fuel, a temperature detection section is provided to detect the temperature of the fuel system of the vehicle, and a load detection unit is provided to detect high load operation. The canister is provided with an atmospheric passage that is open to the atmosphere, and when the fuel system temperature of the vehicle is above a predetermined temperature and the vehicle is operated under high load, the atmospheric passage of the canister is closed to allow atmospheric air to be drawn in. 1. An evaporative fuel control device for a vehicle, comprising an electromagnetic valve that operates to prevent the evaporative fuel from evaporating from the canister and to allow only high-concentration evaporative fuel to be sucked into the intake system of the vehicle. 2. The evaporative fuel control device for a vehicle according to claim 1, wherein the temperature detecting section is a temperature detecting section comprising a thermoswitch provided in a fuel tank and detecting fuel temperature. 3. The load detecting section is a load detecting section comprising a throttle switch that is provided with a switch lever that operates together with a throttle valve and is turned on and off by the switch lever. evaporative fuel control system for vehicles.