JPS6027819Y2 - Purge flow control device for evaporative gas recovery equipment - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of a steam gas recovery device,
In particular, the present invention relates to a purge flow control device for an evaporative gas recovery device that prevents unstable engine operation during cold startup and high-speed warm-up operation.

Traditionally, automobiles, motorcycles, etc. have been focusing on fuel efficiency,
As part of exhaust gas countermeasures, evaporated fuel from the fuel tank is guided into a canister and collected in the canister, and atmospheric air (hereinafter referred to as purge air) is passed through the canister by the suction negative pressure generated during engine operation.

), and the evaporated fuel collected together with this purge air is constantly sucked into the engine and combusted.

Incidentally, in engines equipped with this type of discovered gas recovery device, engine malfunctions often occur during low-speed cold rotation and high-speed warm-up operation.

The purpose of this invention is to eliminate the above drawbacks.
This invention has demonstrated that the cause of engine malfunction is that the air-fuel mixture generated by purge air and discovered fuel is constantly drawn into the intake passage, which prevents the proper air-fuel ratio required at low speeds when cold and at high speeds during warm-up. This was developed by focusing on the problem of misalignment, and its feature is that the air-fuel mixture generated by purge air and vapor fuel is not taken into the intake passage when the engine is cold at low speed or when warm-up is at high flux. In order to achieve this, a purge flow switching valve is provided that cuts off or selectively connects the main purge passage to the intake system purge passage and the exhaust system purge passage depending on the temperature conditions of the engine.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a fuel tank, and after vaporized fuel in the fuel tank 1 is separated into gas and liquid by a separator 2,
The liquefied fuel is recycled into the fuel tank 1, and the vaporized fuel is led to the canister 3.

The evaporated fuel introduced into the canister 3 is collected by activated carbon 4 within the canister 3, and this collection is mainly performed while the engine is stopped.

This canister 3 includes a main purge passage 6 for guiding evaporated fuel collected together with purge air taken in through the atmosphere opening pipe 5 into the intake/exhaust passage during engine operation.
is connected.

The main purge passage 6 is branched into two parts on the downstream side, each of which is a purge passage 7 for the intake system and a purge passage 8 for the exhaust system.

The intake system purge passage 7 is designed to guide the evaporated fuel collected in the canister 3 together with purge air to the intake passage 10 of the engine 9, and a check valve (not shown) is provided in the middle of this intake system purge passage. It is designed to prevent backflow.

The exhaust system purge passage 8 carries the evaporated fuel collected in the canister 3 together with purge air to the exhaust passage 11 of the engine 9.
There is a check valve (not shown) in the middle of this exhaust system purge passage.

) is provided to prevent backflow.

An atmospheric release passage 12 for introducing secondary air is provided on the downstream side of this check valve, and the secondary air is taken into the exhaust system purge passage 8 through a check valve 13 for preventing backflow. It has become.

A switching valve 14 is provided at a branch portion of the main purge passage 6.

This switching valve 14, as shown in FIGS. 2 to 4,
A closed container 15, a thermowax 16 that expands and contracts depending on temperature changes, and a purge passage 6. 7. 8 and a valve body 17 that performs opening/closing control.

The temperature of the cooling water of the engine 7 is transmitted to the switching valve 14 through a wood pipe 18, and the wax 16 expands and contracts in accordance with the temperature of the cooling water.

The movement of the valve body 17 is controlled by the expansion and contraction of the wax 16, and the valve body 17 has a recess 19 for communicating the main purge passage 6 and the intake system purge passage 7, and a main purge passage 7. Small holes 20 are provided at predetermined positions for communicating the passage 6 and the exhaust system purge passage 8.

To further explain this, the switching valve 14 is set at a set temperature (approx.
When the temperature is below 0°C, the valve body 17 is closed as shown in Fig. 2.
The main purge passage 6 is closed to prevent the collected evaporated fuel and purge air from being introduced into the intake/exhaust system purge passages 7 and 8, and the settings are set according to the cold engine temperature. As shown in FIG. 3, when the temperature is above the temperature and below the set temperature (approximately 60° C. in terms of cooling water temperature) determined in response to engine warm-up, the recess 19 of the valve body 17 opens into the main purge passage 6, as shown in FIG. Facing both openings of the intake system purge passage 7, the main purge passage 6 and the intake system purge passage 7 are communicated with each other, and the main purge passage 6 and the intake system purge passage 7 are configured to communicate with each other. Sometimes, as shown in FIG. 4, the opening of the small hole 20 of the valve body 17 faces both the openings of the main purge passage 6 and the exhaust system purge passage 8, so that the main purge passage 6 and the exhaust system purge passage 8 are connected to each other. are connected to each other.

Although the embodiments have been described above, the switching valve 14 is not limited to the wax type as long as it has the above function.

Since the present invention is configured as explained above, it has the following effects.

(1) When the engine is cold, the collected evaporative fuel and purge air are not taken into the intake passage, so the carburetor alone can set the appropriate air-fuel ratio. You can prevent illness.

(2) A severe air-fuel ratio is required when the engine warms up at high speed, but according to the present invention, the collected evaporated fuel and purge air are taken into the exhaust passage and combusted. The air-fuel ratio can be set severely, and engine malfunctions during engine warm-up at high speeds can therefore be prevented, and an increase in unburned exhaust gas caused by engine malfunctions can also be prevented.

(3) During the period from when the engine is cold to when the engine is warmed up, when a severe air-fuel ratio is not required, a rich air-fuel mixture created by the collected evaporated fuel and purge air is drawn into the intake passage. Therefore, the period of use of the choke (or starter) can be shortened, and fuel costs can also be saved.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a system diagram of a purge flow control device of an evaporative gas recovery device according to an embodiment of the present invention, FIGS. 2 to 4 are partial sectional views of a switching valve, The figure is a partial sectional view to explain that the main purge passage is closed when the engine temperature is below cold, and Figure 3 is a partial cross-sectional view when the engine temperature is above cold and below engine warm temperature. Figure 4 is a cross-sectional view to explain that the main purge passage and the intake system purge passage are in communication with each other. FIG. 3 is a partial cross-sectional view for explaining that the device is in a communicating state. 3...Canister-17...Intake system purge passage, 2...Exhaust system purge passage, 10...
...Intake passage, 11...Exhaust passage, 14...
...Switching valve.

Claims (1)

[Scope of utility model registration request] The intake/exhaust system purge passage is closed when the temperature is below the set temperature determined corresponding to the engine cold temperature, and the exhaust system purge passage is closed when the temperature is higher than the set temperature determined corresponding to the engine warm temperature. Only the intake system purge passage is opened when the temperature is higher than the set temperature determined corresponding to the cold engine temperature and lower than the set temperature determined corresponding to the warm engine temperature. A purge flow switching valve is provided at the bottom, and each connection port of the purge flow switching valve is connected to a main purge passage whose one end is connected to a canister, and a main purge passageway in which the vapor fuel collected in the canister is connected to the engine intake passageway together with purge air. An evaporative gas recovery device, characterized in that the evaporative gas recovery device is connected to an intake system purge passage for guiding the evaporated fuel to the engine, and an exhaust system purge passage for guiding the evaporated fuel collected in the canister together with the purge air to the exhaust passage of the engine. Purge flow control device.