FR2573817A1 - Device for starting alcohol-powered engines from cold - Google Patents

Abstract

Device for starting alcohol-powered engines from cold, of the type linked with a carburettor 5 whose float chamber is fed from an alcohol tank 9. In the invention the device comprises in particular two variable-volume sealed chambers 3, 7 separated by a piston 12 controlled by two electromagnets 13, 14 respectively surrounding these chambers, in addition to a series of valves 2, 4, 6, 8 and a tank 1 of volatile fuel such as petrol. Application particularly to engines running on pure alcohol or alcohol in high proportions.

Description

COLD STARTING DEVICE FOR MOTORS OPERATING AT
THE ALCOHOL
The present invention relates to a cold starting device intended to equip an engine running on alcohol.

On engines operating with pure alcohol or in high proportions (greater than 90%), the latent heat of high vaporization combined with the fact that it is a product with little or no light fractions make starting difficult, if not impossible below certain temperatures (for example, below 80C with pure methanol). If starting could have been obtained with an additional device allowing, for example, to introduce a volatile product into the intake manifold, activation during the period when the engine has not yet reached its normal operating temperature generally proves to be very laborious (return holes, stalls) due to poor fuel vaporization.

 It would be possible to remedy these start-up and activation faults if there was a small auxiliary carburetor running on petrol during the difficult period described, then to return to the alcohol supply, once the engine warm.

The device which is the subject of the present invention aims to supply the engine with petrol (or another volatile auxiliary fuel) during the start-up and start-up period using the same carburetor as that used for normal vehicle operation. the alcohol.

To this end, the invention provides a cold starting device, of the type fitted to a carburetor, the tank of which is supplied by an alcohol reservoir, which comprises in particular, according to a feature of the invention - two first and second sealed chambers volume
variable separated by a piston controlled by two
electromagnets respectively surrounding these, - a first valve disposed between the first chamber and a
volatile fuel tank such as petrol, - a second valve disposed between the first chamber and the
upper part of the carburetor tank, - a third valve arranged between the second chamber and the
lower part of the carburetor tank, - and a fourth valve disposed between the second chamber and the
alcohol tank.

This arrangement makes it possible, before starting, to replace part or all of the content of the constant-level carburetor tank with petrol (the term petrol will also denote any other volatile fuel).

Other features and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment given 8 by way of nonlimiting example with reference to the accompanying drawings in which - Figure 1 shows a view schematic of a
cold start according to the invention, - and Figure 2 shows a schematic view of a stop
mobile used in the device illustrated in Figure 1.

A cold start device according to the invention and illustrated in FIG. 1 is associated with a carburetor 5, the constant level tank of which is supplied with alcohol from a tank 9.

This device comprises two sealed chambers 3, 7 of variable volume, separated by a piston 12 controlled by two electromagnets 13, 14 surrounding them respectively and a set of valves 2, 4, 6, 8.

These valves 2, 4, 6, 8 are respectively arranged - between chamber 3 and a petrol tank 1, - between chamber 3 and the upper part of the tank of the
carburetor 5, - between chamber 7 and the lower part of the tank of the
carburetor 5, and - between chamber 7 and the alcohol tank 9.

This cold start device which allows a fuel exchange operates in the following manner during start-up (or just before it) - the coil 14 is energized; the piston 12 moves on the
straight sucking into the cavity 3 a certain amount
tank fuel 1 through valve 2.

Simultaneously, the piston 12 drives the contents of the cavity 7
in the alcohol tank 9 through the valve 8.

- Then, the coil 13 is excited the piston 12 returns to its
original position and therefore
pushes back the quantity of gasoline contained in the cavity 3
in the carburetor tank 5 through the valve 4,
draws the previous contents from the tank into the cavity 7 at
through the valve 6.

The tank is thus filled either with pure petrol, or with a mixture of petrol and alcohol according to the ratios between the volume swept by the piston and the volume of the tank 5.

A modulation of the quantity of gasoline introduced as a function for example of the water temperature can be advantageously envisaged and carried out by means of a movable stop 15 with expandable wax (FIG. 2). Indeed, a minimum quantity of gasoline is necessary in the tank if this temperature is high.

A thermal switch 11 on water temperature switches off the cold starting device when this temperature exceeds a determined value.

As is generally provided for engines running on alcohol, heating the intake manifold with water, it may be advantageous to place this thermoswitch 11 (and the movable stop system 15 possibly) on the water of the intake manifold. 'admission.

The replacement of alcohol by petrol 11 produces two effects: - an increase in volatile fractions, - and an enrichment of the mixture by changing the ratio
stoichiometric.

The fact that the fuel contained in the carburetor tank is replaced makes it possible to obtain operation with the fuel enriched in gasoline for a sufficient period (the time to empty the carburetor tank) to allow the engine to warm up.

If this proves to be insufficient, the coils 14 and 13 can be periodically re-energized (provided that the mobile wax stopper device 15 is available) to return decreasing amounts of fuel to the tank as they heat up. of the motor. This makes it possible to "accompany" this heating for a period longer than the time necessary to empty the tank.

In order to avoid any risk of diffusion of one fuel into the other by internal leaks, it will be advantageous for the pressures to be as close as possible on the two sides of the piston 12 and on the two sides of each valve 2, 4, 6, 8 by a suitable arrangement of the load heights of tanks 1 and 9.

The control of the piston 12 by external coils makes it possible to avoid any risk of external leakage.

Claims (4)

1. Cold start device for an alcohol-powered engine, of the type associated with a carburetor (5), the tank of which is supplied by an alcohol reservoir (9), characterized in that this tool comprises in particular - two chambers (3 , 7) of variable volume, separated by a  piston (12) controlled by two electromagnets (13, 14)  surrounding them respectively, - a first valve (2) disposed between the chamber (3) and a  tank (1) of volatile fuel such as petrol, - a second valve (4) disposed between the chamber (3) and the  upper part of the carburetor tank (5), - a third valve (6) disposed between the chamber (7) and the  lower part of the carburetor tank (5), - and a fourth valve (8) arranged between the chamber (7) and the  alcohol tank (9). 2. Cold start device according to claim 1. characterized in that the stroke of the piston (12) is limited by a movable stop (15), for example with expandable wax, sensitive to the temperature of the engine coolant. 3. Cold start device according to claim 1 or 2, characterized in that it comprises a thermal switch (11) sensitive to the temperature of the engine coolant and capable of canceling the control of the electro-energizers (13, 14) when this temperature exceeds a determined threshold. 4. Cold start device according to claim 2 or 3, characterized in that the movable stop (15) or / and the thermal switch (11) is / are connected (s) to the warming water of the collector engine intake.