FR2930297A1 - DEVICE FOR GAS SUPPLYING A VEHICLE LIQUEFIED PETROLEUM GAS RESERVOIR FOR USE ON STARTING THE ENGINE. - Google Patents

Abstract

The subject of the present invention is a gaseous withdrawal device for a liquefied petroleum gas tank of a land or sea vehicle for use at engine start.This device comprises a double liquefied gas feed constituted by the combination, on the one hand , a liquid phase fuel line (3) from the bottom of the tank (1) associated with a vaporization system (20) of said fuel and, secondly, a gas phase fuel line (4). ) taken from the upper part of said tank and intended to supply the engine during the start-up period, the supply of gaseous fuel being cut off when the engine is sufficiently hot and replaced by the liquefied gas supply. The invention may be suitable for all types of internal combustion engines of the carburettor and injection type, be they stationary engines, land vehicle engines or marine engines.

Description

The present invention relates to a gaseous withdrawal device 5 of a tank of liquefied petroleum gas from land or sea vehicle for use at engine start.

This device relates generally to the technical field of equipment for supplying gaseous fuels of the type 10 liquefied petroleum gas (LPG) or natural gas of the city (CNG) of combustion engines, and in particular engines for combustion. explosion normally receiving a liquid fuel. It may be suitable for all types of carburettor and injection type internal combustion engines, be they stationary engines, land vehicle engines or marine engines.

Liquefied petroleum gas is increasingly used as a source of energy for motor vehicles. This fuel makes it possible to substantially reduce the emissions of CO2, hydrocarbons, NOx, VOCs, etc. compared with that produced by conventional gasoline or diesel fuel combustion engines. LPG is the least polluting fuel available today and its octane rating allows smoother operation, avoiding vibration and noise while increasing engine life. In addition, in many countries, LPG is subject to advantageous taxation allowing a significant reduction in the cost price per kilometer.

The use of liquefied gas to operate an engine originally designed to receive a liquid fuel requires the use of a specific fuel system having an "expander", which vaporises the fuel under a specified pressure and flow rate. . The vapor pressure regulator is usually in the form of a housing comprising a double chamber formed of a gas vaporization chamber and a thermal chamber in which a hot liquid circulates, which is often constituted by the cooling water of the engine removed. thanks to a -2- derivation on the circuit connecting it to the radiator. Both chambers have a common wall arranged to allow a good transmission of calories. The heating of the expander can also be obtained by the engine lubricating oil (patent No. FR 2 764 002), or by an electric heating element incorporated (patent No. FR 2 759 419) or external (patent No. FR 2,780,102). It should be noted that the vapor pressure regulator may be formed of two independent parts connected by a single pipe, a regulator of the flow and pressure of the vaporized gas, connected to the engine, and a vaporization element consisting of a heat exchanger consisting of a tube a heat-conducting material in which the gas passes, liquid at the inlet connected to the feed tank and gaseous at the outlet, this tube being immersed in a heating liquid contained in a chamber (Patent No. FR 2 801 643 ). (The above-mentioned patents have been filed by the applicant of the present invention).

Currently, the vast majority of vehicles running on liquefied petroleum gas (LPG) or natural gas (CNG) have a dual fuel supply: - the tank of liquefied gas connected by a first pipe to a vapor pressure regulator and a regulating element flow and pressure. - A tank of gasoline or diesel fuel connected by a second pipe to the carburetor or an injector supply rail. This second feed is used to allow the engine to start and run until the temperature of the cooling water or lubricating oil is high enough to ensure vaporization of the liquefied fuel. .

Indeed, when the engine is cold, the heat transfer fluid of the vaporization element can not be hot enough to provide the gaseous fuel the calories necessary for its vaporization. Under these conditions, it is generally used a parallel supply circuit of gasoline or diesel to run the engine until the latter has reached its optimum operating temperature, that is to say a temperature sufficient for the The heat transfer fluid of the vaporization element is sufficiently hot to vaporize the liquefied gaseous fuel. Once this optimum operating temperature is reached, the fuel supply circuit is cut off from the main liquefied gaseous fuel supply circuit. This is commonly called bi-injection or bi-carburation. Although effective, this technical solution is however complex and expensive.

It is possible, by taking the liquefied gaseous fuel at the top of the tank, to obtain it directly in gaseous form and to feed a carburetor or injectors without using a vaporizer. However, this can only be used for a shorter duration or for very low power engines because the vaporization in the tank produces a drop in temperature resulting in a short lapse of time the icing of the pipes and connecting members .

The purpose of the device according to the present invention is to allow the use of liquefied gaseous fuel for a standard type of explosion engine without requiring the use of a second fuel or gas oil supply to ensure starting.

It consists of a dual liquefied gas supply formed from the combination of a vaporization system using the heat of the coolant or the engine lubricating oil to heat the fuel taken in the liquid state in the reservoir , and liquefied petroleum gas sampling equipment at the top of the tank for supplying the engine during the start-up period, the supply of gaseous fuel being cut off when the engine is sufficiently hot and replaced by the supply of liquefied gas through solenoid valves.

In the accompanying drawings, given by way of nonlimiting example of one embodiment of the object of the invention: FIG. 1 represents a schematic view of the entire gaseous fuel supply system; liquefied, the lid of the tank connection box being removed, FIG. 2 is an enlarged longitudinal section of the

4-vaporization showing the internal structure of the latter and corresponding to the detail Dl of Figure 1, Figure 3 is a vertical section of the tank along the arrows F1 of Figure 2 and Figure 4 is a partial view of a variant of the heating system of the vaporization system, this view showing the connection of said network on a calorstat support.

The device, FIGS. 1 to 3, consists of a tank 1 of liquefied gaseous fuel 2 equipped with two engine supply lines, a liquid phase fuel line 3 and a gas phase fuel line 4.

The tank 1 is of any shape of the type customarily used for liquefied petroleum gas (LPG) or natural gas of the town (CNG) and comprises a tube 5 for withdrawing the liquid phase fuel, which ends at the bottom of the tank and is equipped with a control electro-valve 6 at its outlet, and a filling pipe 7. The tank 1 may be designed to replace a tank of gasoline or diesel.

The tank 1 is equipped, in addition to the usual equipment such as level gauge, safety valve, etc., a solenoid valve 8 mounted on a nozzle installed on the upper wall 9 of the tank and having a short tube 10 terminating above the upper level 11 of the liquefied fuel 2 so as to withdraw the latter in the gas phase.

The liquid phase fuel line 3 may comprise a safety solenoid valve 12 arranged upstream of a three-way connector 13 to which are connected, in addition to the liquid phase fuel supply, the gas phase fuel line 4 and the tubing supplying the regulating element 15 with the flow rate and the pressure of the vaporized gas supplied to the engine, this tubing being connected directly to the carburettor or to the injection system in the case of a vapor-expander in a salt element. The solenoid valve 8 for drawing off the gas phase fuel

-5- may possibly be mounted near the three-way connector 13.

The fuel in the liquid phase 2 passes, before reaching the safety solenoid valve 12, by a vaporization system 20 advantageously constituted by a tubular element 21 in which circulates the engine coolant taken from a bypass consisting of 22 and a return pipe 23. In the case of a marine engine, in particular of the outboard type, the withdrawal pipe 22 and return pipe 23 will advantageously be connected to the engine cooling circuit by means of a specific thermostat support 24 arranged so that the flow in these pipes is controlled by said thermostat, FIG. In general, the metal equipment to be used for a marine engine will be made of corrosion resistant materials.

The tubular element 21 is formed of a sealed enclosure preferably made of deformable insulating material, and in which passes the fuel line in the liquid phase 3. This sealed enclosure may consist of a reinforced rubber hose type "hose or the like and closed at both ends by an upstream connection 25 and a downstream connection 26 traversed by said vaporization tube.

The heating of the vaporization system 20 can also be obtained by the engine lubricating oil, or possibly by an external electric heating body connected to said system by pipes traversed by a suitable liquid.

The control valves 6 for liquid fuel outlet and for sampling 8 for gaseous fuel as well as the vaporized fuel supply safety solenoid valve 12 are controlled by a system able to determine when the vaporisation system temperature 20 is sufficient to ensure the passage in the gas phase of the fuel taken from the liquid phase. At startup of the engine, the control electrodes 6 and safety valves 12 of the liquid phase fuel line 3 are closed, the gaseous fuel sampling solenoid valve 8 is open. As soon as

-6- control system detects that the vaporization temperature is sufficiently high, it causes the opening of the control solenoid valve 6 and the electro-safety valve 12 of liquid phase 3, and the closing the solenoid valve 8 for gaseous fuel. This arrangement makes it possible to use the fuel in the gaseous phase for a sufficiently short period to prevent icing of the pipes and connecting members while eliminating the need for a second tank containing gasoline or gas oil.

The gas phase gas sampling system can be arranged so that it can be used for feeding heating or cooking appliances in a "home-car" or a towed caravan.

The positioning of the various constituent elements gives the object of the invention a maximum of useful effects which had not been obtained so far by similar devices. 10