GB2142383A

GB2142383A - Carburettor with overrunning air supply to the idling system

Info

Publication number: GB2142383A
Application number: GB08317815A
Authority: GB
Inventors: Dei Lai Min
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-06-30
Filing date: 1983-06-30
Publication date: 1985-01-16
Also published as: GB8317815D0

Abstract

Air from a filter is admitted to the idling mixture passage 14 when a valve 36 is opened by a diaphragm 34 in response to overunning vacuum in the intake 14 manifold 42. <IMAGE>

Description

SPECIFICATION An improved carburettor This invention relates to a low speed economy device for vehicle carburettors and more specifically to a device which is able to open an air valve automatically in circumstances where the vehicle concerned is reducing its speed.

As a rule, ordinary automobiles using gasoline as fuel will call for a release of the throttle while going downhill or when changing gear or executing a braking action. If the throttle valve in the carburettor is at the minimum position or if the engine is started up by using the drive wheels to drive the engine, the consequence is that the engine will induce a strong vacuum on the underside of the throttle valve (larger that the idle speed), causing a big demand for fuel. The mixture that would eventually be delivered may not be completely combusted, or worse still, combustion of the mixture may even take place in the exhaust passage, thus not only causing a waste of energy but also releasing undesirable emissions into the air.

A method of saving fuel that prevails currently is to reduce the amount of fuel to be delivered by reducing the size of the fuel nozzle; this ignores the fact that there is a prescribed ratio for the air/fuel mixture. Attenuation of the mixture will inevitably give rise to improper combustion, worsening of acceleration characteristics and even explosive shocking of the engine thus rendering the engine faulty easily, shortening service life of the engine and bringing unnecessary troubles to the driver.

It has often been the case that in order to save fuel, a driver would let his car glide along downhill or travel along in Neutral Gear whenever the car was going at extremely high velocity, and this is very dangerous indeed should there be a shifting of center of gravity or an emergency condition, because of the total absence of engine drive to keep the car under control.

According to the present invention there is provided a low-speed economy device for the carburettor of a vehicle, comprising an air intake control mechanism having a connection to an air purifier, and air intake by-pass passage connected to said intake control mechanism, a low speed fuel network connected to said by-pass passage and to the engine of the vehicle to feed the cylinders of the engine, said air intake control mechanism including a valve gate to block and unblock said air intake by-pass passage from its connection to the air purifier, and having a connection to the fuel inlet manifold of the carburettor and to a throttle valve of the carburettor, and means connected to said valve gate for automatically moving said valve gate between its blocking and unblocking positions, whereby with a vacuum in the fuel inlet manifold when the throttle valve is closed said means moves said valve gate to its unblocking position allowing air from said connection to the air purifier into said air intake control mechanism and via said by-pass passage into said low-speed fuel network to feed the air to the cylinders of the engine.

By way of example, an embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a section through a device according to the invention.

Fig. 1 shows a low-speed economy device 10 for use with the carburettor of a vehicle.

The device 10 has an air intake by-pass passage 1 6 provided on the bleed pipe 14 of a low-speed fuel network 1 2. By means of an adaptor 16a, the by-pass passage 1 6 is connected to the outlet 22a of an intake control mechanism 1 8. The intake control mechanism 1 8 comprises a base portion 28 which is dishshaped and has a tubular extension 26 at the bottom thereof, and an lid portion 32 serving as a hood over the base portion 28. A chamber 24 adjoins the lid portion 32, the chamber 24 having an intake passage 30 and exit passage 22. A rubber plug 36, which is fitted onto a diaphragm 34 that is set between the base portion 28 and the lid portion 32, serves to control the access of port 22b to the exit passage 22.A tubular connector 38, screwthreadedly engaged with the tubular extension 26 of the base portion 28, is connected to the manifold 44 of the gas access tubework 42 that leads to the engine. The tubular connector 38 permits adjustment of the tension of a spring 40 that is set between the connector 38 and the diaphragm 34 to ensure that the rubber plug 36 that is fitted to the diaphragm 34 will normally be biased by the spring 40 so as to close off port 22b.

An automobile or other vehicle incorporating the low-speed economy device in its carburettor will function to have the throttle valve 60 in the carburettor shut off at a minimal position as the accelerator is released when, for example, the automobile is running downhill or changing from a higher speed to a lower speed or is on the point of effecting a braking action. At such time, the engine's speed of rotation would remain above about 950 RPM, which is equivalent to a speed of more than about 25 KPH in top gear. When this happens, the engine will momentarily create a strong vacuum on the underside of the throttle valve 60, which in turn will pull down the diaphragm 34 of the intake control mechanism 1 8 and serve to have the rubber plug 36, as fitted to the diaphragm 34, detached from its closed off position with respect to port 22b.The result is that the port 22b is openend. Since the intake passage 30 is connected to an air filter A. the air fed in from the filter A will get stuffed and packed in the bleed pipe 14 of the low-speed fuel network 1 2 by way of the exit passage 22 and the by-pass passage 1 6 and thence find its way into the engine. The process related above will serve to pass air into the engine to aid complete combustion of the fuel so as to reduce waste. Furthermore, the reduced consumption of the carburettor thus achieved will serve greatly to reduce the amount of fuel fed from the fuel network, thus achieving the objective of fuel saving.

The air intake control mechanism 1 8 as related herein before will function to allow the throttle valve in the carburettor to move to a more wide open position as the automobile incorporating the device is accelerated to travel at higher speeds. As the demand from the engine is stepped down, the diaphragm 34 will be restored to its original position auto matically under the biasing action of spring 40 and consequently the rubber plug 36 will be set to close off port 22b once again.

Claims

1. A low-speed economy device for the carburettor of a vehicle, comprising an air intake control mechanism having a connection to an air purifier, an air intake by-pass passage connected to said intake control mechanism, a low-speed fuel network connected to said by-pass passage and to the engine of the vehicle to feed the cylinders of the engine, said air intake control mechanism including a valve gate to block and unblock said air intake by-pass passage from its connection to the air purifier, and having a connection to the fuel inlet manifold of the carburettor and to a throttle valve of the carburettor, and means connected to said valve gate for automatically moving said valve gate between its blocking and unblocking positions, whereby with a vacuum in the fuel inlet manifold when the throttle valve is closed said means moves said valve gate to its unblocking position allowing air from said connection to the air purifier into said air intake control mechanism and via said by-pass passage into said low-speed fuel network to feed the air to the cylinder of the engine.

2. A device as claimed in claim 1, wherein said air intake control mechanism comprises a base portion, said connection to the fuel inlet manifold of the carburettor including a tubular extension connecting said base portion to the fuel inlet manifold, a lid portion enwrapped over said base portion, a chamber annexed to said lid portion and having intake and exit passage into and out of said chamber, said means for automatically moving said valve gate including a diaphragm fixed between said base portion and said lid portion, said valve gate including plug means fixed to said diaphragm to control access to said exit passage, and adjustable spring means for biasing said plug means towards sealing off said exit passage.

3. A device as claimed in claim 2. wherein said adjustable spring means includes a connector screw-threadedly engaged with said tubular extension and having a passage therethrough for connection to the fuel inlet manifold of the carburettor, and a spring connected between said connector and said diaphragm for adjustment by movement of said connector to regulate the biasing force of said spring between said connector and said diaphragm.

4. A low-speed economy device substantially as hereinbefore described with reference to and as shown in the accompany drawings.