ITFE20060039A1 - ELECTRONIC GEAR REDUCER / VAPORIZER FOR SEQUENTIAL ELECTRONIC INJECTION SYSTEMS SET FOR LPG IN ENDOTHERMAL ENGINES WITH CONTROLLED IGNITION - Google Patents

Description

DESCRIPTION

Description of a gas engine with electronic injection

First of all, we want to give a brief but global description of the main characteristics and operation of an isodemo system for the sequential electronic injection of GEI * in the gaseous phase in a controlled ignition soie r.

The fuel

GEL (Liquefied Petroleum Gas) and a gas mixture essentially composed of Propane (C3HS) and Butane (€ *! 1⁄2}, - in slightly variable proportions depending on the season, 11 Propane, more volatile, is always pressed in a higher percentage (about 76-60% of the total. ©) than Butane # whose quantity is increased in summer precisely because of its lower volatility.

The gas mixture thus composed gives rise to a fuel, the GEL precisely, which in ambient conditions (pressure of about 1 bar and temperature of about 26; * C) is also in the gaseous phase, but it is sufficient, however, to use a few bar to obtain liquefaction.

In autogas systems, the SPI * is stowed inside the tank in the liquid phase at a pressure that is on average

THE! applicant

around 4/6 bar. Téle value also varies in the finishing of the. fill level of the tank.

A modern system for powering the latest generation spark ignition engines, equipped with: electronic fuel injection management and catalytic converter, is essentially composed of:

Ξt * rìriritO3..Ο

Reduce / zzabore vapors

Electronic injectors and Rail

Electronic control unit

These components can be considered essential since they characterize the type of system, which is completed by accessories of more general use such as solenoid valves, sensors and various connecting and fixing elements.

Reservoir

It is made of steel and generally has a cylindrical or toroidal shape. management of the quantity of gas present in the tank {level sensor,

applicant: τ. 5 load limiter at 801 of the volume} è systems - «11. sicul'ernia, such as the thermo-fuse and the overpressure valve which prevent the bursting in case of fire © excessive pressure increase.

The nducer / vaporizer

This component is located immediately downstream of the tank and has the purpose of adapting the chemical-physical conditions of the gas taken from the tank to those necessary for powering the engine.

The gas that reaches the reducer / vaporizer is in the liquid phase and is under pressure, therefore easo basically has two functions, that of vaporising the LPG and of reducing its pressure to the <'> value required for the injection {usually 1 * About 2 bar} *

This occurs by introducing the gas into a chamber whose volume increases in the reverse of the motion, thus favoring the expansion of the gas and its vaporization. This chamber is made in different ways by the various manufacturers, but very often has the shape of a spiral whose width is constant while the height increases in the direction of the motion fFxg * 1-a}. In this way the expansion of the liquid gas is realized, which it vaporizes. The passage of: phase from liquid to gas inevitably occurs with absorption of heat from the gas itself and thus causing a lowering

The applicant; SCG

of the temperatures, which can also bring the system to the key congeiaBto. To limit this risk *. The reducer / vaporizer is equipped with a second chamber {Fig. 1-b}, adjacent to the first, inside: of which flows the water of the cooling circuit: of the engine, intercepted upstream of the radiator, when it is still at a high temperature. The heat supplied by the water, is transmitted by conduction to the whole system, it is generally made of aluminum; it compensates for the cooling consequent to the expansion of the gas.

Electronic injectors e

LPG, in the gaseous phase and at the predetermined pressure, coming out of the regulator / vaporiser reaches the injectors, particular solenoid valves whose opening is regulated by the electronic control unit in phased sequential mode. In other words, injection takes place in one cylinder at a time, coinciding, for each of them, with its intake phase.

In order to stabilize the gas pressure upstream of the indectotes, so as to be able to adjust <:> the quantity injected only within the opening time of the injector, a volume ( You know!} That its purpose is to dampen the oscillations that inevitably there

the applicant: 7 undergoes pressure as a result of the centin.ua opening and closing of the injectors and the shutter

Electronic control unit

The sideriti autogas systems for the electronic injection of GPli are equipped with their own specific 3⁄4a control unit with the function of managing the gas supply of the engine but also of keeping all the main functional parameters of the system under control. It # "communicates * constantly with the main control unit installed on the engine # and on the basis of the signals received from the various pressure sensors is the temperature of the system, it determines # for each operating condition # the parameters with which to manage the power supply of the engine # such as the advance and the injection time.

The applicant:

THE INVENTION

1 / the proposed invention relates to the realization of an electronic reducer / vaporizer,

The system, created as a 3Q model, is characterized by its original shape, which incorporates the Rail and the injectors and redraws 1 <T> water and gas flow trends, and above all for the adoption of an electronic device (and therefore managed by control unit) for 1 * shutter opening, replacing the mechanical / pneumatic one, commonly used,

The Fxg „2 shows in section the model 3 © of a mechanical reducer equipped with a shutter opening system by means of an axial pin; in other solutions, a swath lever mechanism is adopted.

The admission of liquid gas into the reducer / vaporiser # occurs through a special inlet fitting f "a" in Fig. 2) and is regulated by a shutter C "b" in Fig. 2), equipped with a spring C "c" in Fig. 2ìts on which acts, by means of a spinet i "à * in Fig, 2), a membrane p <w> in Fig, 2) which is subject to the pressure of the gas and is pushed by a spring (" f "in Fig, 2)

The applicant; 9 In order to keep the shutter open; the spring which acts on the diaphragm is usually preloaded and equipped with a screw device ("g" in Fig. 2) for adjusting this preload, therefore the injection pressure.

As long as there is a demand for gas, the expansion of the gas (Fig. 3) keeps the pressure low and keeps the shutter open, allowing liquid gas to enter the regulator / vaporizer, when, conversely, no flow rate is required (release phase ), the increase in gas pressure, acting on the membrane, generates a force that causes the shutter to close (Fig, 4).

OPERATION OF THE ELECTRONIC REDUCER

The electronic reducer is represented in Fig. 5-a and Fig. 5-b in two axonometric views of the assembly and in Fig. 6 in an exploded view. It is characterized by a cylindrical development in which the chambers, for the expansion of the gas and the circulation of the heating water, are made up of longitudinal through channels; some small chambers are obtained inside the two side faces of the reducer body and in the two side covers with the purpose of allowing the inversion of the relative flows, that of gas and that of water. In the first case, at each inversion there is an increase in the total passage section, which allows the expansion of the gas.

The applicant: <'> J <T>, 10 Figs, 7-a and 7-b show the path of the gas; through the reducer: the liquid gas enters the duct indicated by the arrow 1 in Fig. 7-a and passing through the shutter, when it is open # <■> it runs through the entire through channel coming out of the hole indicated by the arrow 2 in Fig. 7-b. Here it fills the entire chamber Gl dì Fìg. 7-b taking the two channels indicated by arrows 3 in Fig. 7-b. In chamber C2 of Fig. 7-a the same inversion of motion occurs, the gas escapes from the holes indicated by arrows 4 to enter the Rail indicated by arrow 5.

Figure 8 shows the exploded detail of the shutter control device. The shutter ("b" in Fig. 8} is equipped with a closing spring f ^ a "in Fig. 8): <& · a rubber sealing disk f" c "in Fig. 8) and is inserted in a cylinder of ferromagnetic material ("d" in Fig. 8) in turn surrounded by the electromagnet ("e" in Fig. 9}. The spring keeps the shutter closed until the magnet is powered; Fig. . 9-a); faulty cheek is excited, the electromagnetic field that is generated produces the shutter opening (Fig. 9-bj, The electric impulse must be generated by the control unit which for this reason must be specially prepared. purpose # a sensor is inserted in the reducer which detects the pressure inside the Hall; when this falls below the preset value, the control unit commands opening

The applicant: ì of the shutter "vice versa, if the value exceeds a predetermined upper limit, it commands its closure. Fig. 10 shows the passage of gas through the open shutter while Fig. 11 shows the condition in which the shutter is closed.

In Figures 12-a and 12-b the path of the heating water is highlighted. 1 / water from the engine cooling circuit, before passing through the radiator, is conveyed into the reducer through the duct indicated by arrow 1 in Fig, 12-a. 12-b and fills the chamber C3 entering the channel indicated by the arrow 3 of Fig. 12-b. once: when the motion is reversed, the water leaves the hole indicated by the arrow 4 in Fig. 12-a and returns to the engine cooling circuit.

INNOVATIONS AND ADVANTAGES SOLUTIONS PROPOSAL <■>

With the adoption of an electronic shutter control, it is possible to obtain numerous advantages, in terms of *

SAFETY

With 1 * mechanical shutter, when the engine is switched off, closing of the shutter itself is not always guaranteed. It depends on the difference

The applicant: 12

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pressure which rests inside the reducer between the two chambers separated by the diaphragm, taking into account that the spring always tends to keep it open, the electronic shutter is instead a solenoid valve which, when not energized, i.e. with the engine off, closes automatically.

PERFORMANCE

The possibility of. - manage the quantity of: liquid gas that feeds the collector / vaporiser. with the precision typical of electronic systems, it allows to have a device with a high response speed and therefore much more ready in <'> adapting the gas flow rate to the user's requests. This also makes it possible to better respect the fundamental condition for the correct realization of the phased sequential electronic injection, that of keeping the pressure inside the Rati as constant as possible.

RELIABILITY AND MAINTENANCE

A complex system, no matter how simple the mechanical shutter ceases, requires: adequate maintenance and can be subject to malfunctions and breakdowns that require assistance. Not of

The applicant: 13 shafts. breakage of the membrane occurs © blockages of the moving or sealing parts, caused <'> by wear and often by the impurities always present in the automotive gas. The application of a solenoid valve drastically reduces the number of components used, almost completely eliminating the number of moving components and Co-ring sealing).

DIMENSIONS

As mentioned, the mechanical shutter is a complex system, already made up of various components in itself. It also has a significant impact on the overall dimensions of the reducer / steamer.

1 / the obturator in fact works due to the effect of pressure which # acting on the diaphragm determines the force that compresses the spring. In order not to work with too high pressures, it is necessary to increase the size of the diaphragm. By eliminating the membrane and the numerous components of the mechanical shutter, it was possible to design a reducer / vaporizer of much smaller dimensions.

The model created is also distinguished by the innovative solution of integrating in a single component, the reducer / vaporizer, the Rail -a the injectors.

iedente: 14 These are between elements incorporated into one, having smaller dimensions than just the mechanical reducer / steam generator "

INSTALLATION

The reduced dimensions of the electronic reducer / vaporizer make its installation in the outlined engine compartment safer and faster * This reduces atlC.be to the risk of errors during assembly and the inevitable interventions on series components.

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Claims (1)

Ff 200 8 1000039 CLAIMS 1. St claims the idea of using an electronic type device for controlling the shutter and thus for managing the quantity of liquid gas entering the reducer. The realistate model has resorted to using a solenoid valve, but the considerations made do not matter from the specific characteristics of the! The electric motor used and is believed to remain valid even if another type of electric actuator is used, such as a stepper motor, to control the opening / closing of the shutter. realize the expansion of the gas by means of a volume that develops according to channels of cylindrical shape of increasing section, with: l suitable chambers for inversion of the motion, and culminates directly in the rare. !