ITRM20120068A1 - ELECTRONIC DEVICE WITH SYMMETRICAL STAGE OF INHIBITION AND EMULATION SWITCHING INJECTORS FOR OPERATION WITH TWO OR MORE FUELS - Google Patents

Description

DESCRIPTION

accompanying a patent application for an industrial invention entitled:

- ELECTRONIC DEVICE WITH SYMMETRIC STAGE OF INHIBITION AND EMULATION

SWITCHING INJECTORS, FOR OPERATION WITH TWO OR MORE FUELS "

FIELD OF INVENTION

The invention relates to a new electronic device for powering internal combustion engines, which can also use a second alternative fuel, in an adaptive and proportional manner, by easily integrating said device into the original electronic injection system of the fuel. The invention is therefore placed in the field of application of mechanical internal combustion engines and in the technical field of active injectors for the modulated injection of fuel.

PREVIOUS STATE OF ART

Modern petrol-fueled automotive engines have an electronic control unit which, taking into account variable parameters such as the number of revolutions per minute, the mechanical torque exerted, etc., constantly calculates the optimal quantity of petrol to be introduced into the cylinders of the engine and consequently activates the petrol injector devices appropriately. Normally each cylinder receives fuel through an injector, which is electrically operated by an electronic circuit, called â € œdriverâ €, located in the aforementioned electronic control unit. The driver controls the electric current that passes through the injector and generates a sufficient magnetic field inside it to move a shutter, in order to open a nozzle through which the petrol can flow into the cylinder. The quantity of gasoline that passes depends both on the opening time of said nozzle and on the fuel pressure, and these two factors are constantly controlled by said control unit.

In order to feed the petrol engine also with an alternative fuel, such as methane or LPG, it is necessary to install a second tank and a second fuel system with an additional control unit: call control unit for alternative fuel, necessary to control the alternative fuel injectors, which are usually applied to the intake manifolds. In general, alternative fuels can be injected both in liquid and gas phases: in the first case a pump is used to push the alternative fuel with the necessary pressure, in the second case a heating evaporator with stabilized output pressure is used.

The control unit for alternative fuel, in addition to calculating and controlling the quantity of alternative fuel to be delivered through the appropriate injectors, must however also inhibit the operation of the petrol injectors, and must do so in a non-intrusive way, that is, in such a way that the original control unit does not notice it. If this were not the case, the original control unit, activating its own diagnostic checks, would reveal the presence of a foreign component or the defect of an original component, and would signal the problem through the lighting of an engine warning light, â € œcheck engineâ € , and could also implement â € œrecoveryâ € strategies that would lead to unsatisfactory operation in terms of poor engine combustion and generation of pollutant emissions.

Therefore, the alternative fuel control unit includes a special device, called the petrol injectors "emulator", which is used to make the petrol control unit work correctly as if the petrol injectors were operational; while they are actually inhibited.

In practice, to also install an alternative fuel system, it is necessary to interrupt the original connection between each petrol injector and the corresponding driver, and then connect the latter, by means of connectors or solder wires, to the aforementioned injector emulator device of the gas; which can be inside the alternative fuel control unit or even outside. Substantially, said emulator device contains an electrical impedance of an appropriate value, that is, to satisfy the diagnostic checks of the petrol ECU and at the same time reduce the passage of current and therefore the magnetic field inside the petrol injector in such a way as not to make it open the nozzle further, thus effectively cutting off the flow of petrol to the engine.

Fig. 1 illustrates what has been described so far, in the case of an ordinary four-cylinder engine fueled with petrol, where the four petrol injectors B are connected on one side to the battery voltage V and on the other to the respective drivers D located in the electronic control unit for petrol C.

Fig. 2 refers to a single petrol injector B, but also applies to all the others, and shows that, in order to use the alternative fuel, the connection L must be interrupted and, between the two points Lâ € ™ and Lâ € so ¬ obtained, introduce the emulator device E mentioned above. From now on, for simplicity, it will be considered the single injector, as it can be understood that the discussion easily extends to the others.

Fig. 3 schematises a circuit of the aforementioned emulator device E of the petrol injector, formed by a relay R which has the contact K normally closed so as to short-circuit the impedance Z. When the engine is fueled with petrol, all the current supplied by the driver D of the petrol control unit reaches, through the contact K of the relay R, the petrol injector B, which is therefore operational ... When instead the engine is fed with alternative fuel, then the control unit for the alternative fuel G commands the relay R to open the contact K and thus inserts the impedance Z in series with the connection between the driver D and the petrol injector B, which is therefore inhibited because © receives insufficient current to open the nozzle.

The solution described in the FSG. 3 however does not give satisfactory results, on the contrary it is quite limiting for current applications: as, for example, it does not allow the progressive passage from operation with petrol to that with alternative fuel, because switching the relay enables operation or with the petrol or with alternative fuel, and the snap between these two types of operation is sometimes very abrupt with consequent loss of power and misfires, â € œmisfireâ €, which can be detected by the diagnostic checks of the petrol ECU with consequent malfunctions .

The market also offers other solutions, technologically more advanced, which allow the gradual transition from petrol operation to alternative fuel operation and also allow the implementation of temporary petrol operations, possibly localized only on some cylinders, to solve the problem of â € œmisfire "mentioned above and optimize combustion in certain operating regions, thus also trying to preserve the integrity of the engine and catalyst. For example,

Fig. 4 schematises a typical modern example of a control unit for alternative fuel G containing an emulator device E of the petrol injector; which has, in parallel to the impedance Z, an additional active component, consisting for example of a transistor T of the MOSFET type. During operation with alternative fuel, the relative control unit G drives transistor T so as to short-circuit the impedance Z and thus restore the flow of current for the petrol injector B, which therefore resumes operation. This solution allows gasoline to be injected into the engine also during operation with alternative fuel; the carburetion control is guaranteed by an appropriate compensation on the quantity of alternative fuel introduced. Therefore, when you want to switch the power supply of the engine from petrol to alternative fuel, it is possible to progressively reduce the quantity of petrol introduced into the engine, also by acting sequentially on one cylinder at a time, in order to inhibit one petrol injector at a time, and instead gradually increase the injection of alternative fuel by enabling the relative injectors one at a time. Consequently, the fuel changeover in the engine takes place gradually, in a soft way, without disturbing the driver of the vehicle and without creating problems for the petrol control unit, which will have no reason to diagnose malfunctions.

Usually modern control units for alternative fuel establish the driving times of their injectors by deducting them from those established by the petrol control unit; for this purpose, each emulator device E of the petrol injector also contains a special sensor S which perceives the electric command generated by the driver D.

Fig. 5 illustrates a generic petrol injector emulator device E which also contains the aforementioned sensor S.

However the presence of the transistor T requires, as an expert in the art, a precise polarity. This means that during the installation phase the electrical connections must be made with scrupulous attention to the polarity, because if two connections are inverted, statistically frequent case with the solder wires, the emulator device would receive an inverted polarity and could not work, with the risk indeed to create damage. Fig. 6 illustrates the risk of such an unpleasant eventuality, for which, for example, if the transistor T is of the power MOSFET type, then the diode J incorporated in it can be crossed by a current such as to travel also the injector enough petrol B to open the nozzle, thus causing unwanted petrol injection when running on alternative fuel.

DESCRIPTION OF THE INVENTION

The invention determines a significant improvement in the technical specification with respect to the state of the art mentioned above, for the following reasons of distinction.

the first reason for distinction lies in the fact that the invention introduces a new petrol injector emulator device, having innovative architectural characteristics, in particular symmetrical, with regard to the electrical connections required during the installation of the system. It always allows for the possibility of gradually switching the operating mode with petrol and that with alternative fuel, as well as the possibility of carrying out operations with petrol even during operation with alternative fuel, in line with the most modern state of the art. . To all this, however, the invention brings a double additional advantage:

- avoid malfunctions and damage resulting from inverted electrical connections;

- make the electrical connections much easier and faster.

This double advantage derives from a first salient feature of the present invention, namely in the fact that the electronic circuit of the new petrol injector emulator device has a symmetrical architecture, which eliminates any need for polarization in the electrical connection. This therefore becomes easier and faster, and moreover without the risk of malfunctions and damage caused by reversed electrical connections.

Fig. 7 schematizes said innovative electronic circuit having symmetrical architecture - illustrated here purely by way of example and certainly not exhaustive, given that different technologies are available to obtain equivalent results - according to a first form preferred by the inventor, where it is seen added, in series with the first, also a second transistor Tâ € in symmetrical configuration; in this case, when fueling with petrol, the relay R closes the contact K between the driver D and the petrol injector B; on the other hand, when feeding with alternative fuel, the relay opens the contact K and the current of the petrol injector B passes through the impedance Z. with alternative fuel, as well as the possibility of fueling with petrol even while feeding with alternative fuel, is made possible by the presence of transistors T and T and diodes Jâ € ™ and Jâ €, which in certain MOSFET components of power are also integrated internally to them, but which can also be applied externally. As an expert in the art can easily understand, when it is desired to fill in petrol even during operation with alternative fuel, the control unit for the alternative fuel G appropriately drives the transistor T so that this allows the current to pass through the diode Jâ And to injector B sufficiently to cause the mechanical opening of the nozzle. This solution preferred by the inventor foresees to introduce also two other impedances Z and Zâ € of identical value and much higher than that of the impedance Z, and to put them respectively in parallel to the transistors TP and Tâ €, so that the node the central unit common to them and to the two transistors is used to apply the sensor S, which is used by the control unit for the alternative fuel G to know the timing of the fuel injection.

Fig. 8 shows that, by inverting the connection diagram described above, the operation of the device still remains correct. In fact, thanks to the aforementioned innovative symmetrical architecture of the circuit, this time the transistor Tâ € and the diode Jâ € ™ come into play to pass the current of the injector B; while nothing changes for the sensor S which is applied to the center of the symmetrical configuration.

Fig. 9 shows another embodiment of the invention, with the same advantages described above, where the petrol injector B is activated by the current flowing through the diode Jâ € ™ and the transistor Tâ €, which is driven by the ECU for the alternative fuel G. By inverting the connection diagram, the diode Jâ € and the transistor T 'are involved, so that the circuit symmetry of the device makes it work even by connecting it with inverted polarity. This also applies to sensor S, as it is applied in the center of a symmetrical circuit.

The second reason for the distinction of the invention lies in the fact that, compared to traditional devices, it also denotes a marked technological improvement which translates into the following three further advantages:

- lower electricity consumption;

- improved efficiency of the device due to the reduced waste of dissipated thermal power; - more powerful miniaturization of the device;

as explained below with the help of the following figure.

Fig. 10 introduces yet another embodiment of the invention, where the impedance Z previously considered is now replaced by a special active circuit A. Ordinarily the devices that we find on the market contain the impedance Z , which is a passive component and rather bulky because it has to dissipate a considerable thermal energy: in fact it typically admits a current of about 200 mA which, with the nominal voltage of about 15V generated by the battery, means a power of about 3W which is dissipated as thermal energy. According to the invention, on the other hand, this impedance Z is replaced by the aforementioned active circuit A, which develops an original application of the so-called â € œswitchingâ € technique, well known in a different field of application which is that of high efficiency power supplies, characterized precisely from the low dissipation of thermal energy. It follows that the new petrol injector emulator device also has high efficiency and low dissipation of thermal energy. This lower expenditure of thermal energy is equivalent to a lower need for electricity. Furthermore, the reduced need for dissipation allows to further miniaturize the device itself.

Fig. 11 shows, purely by way of example, an example of said active circuit A, also called recirculation circuit, here adapted to the above mentioned function, but technically already known in the art and therefore there is no need to explain it further . Suffice it to say that the alternative fuel control unit G drives the two transistors TP and Tâ € in switching mode with duty-cycle control, while enabling the active recirculation circuit A by sending a specific command on input H; in this way in the petrol injector B a recirculation of current is formed through the recirculation circuit A and the diode Jâ € ™; in case of connection with inverted polarity the diode Jâ € is involved. Therefore the current flowing in the petrol injector B can be controlled electronically through the input H; in such a way that, when feeding with alternative fuel, said current is not strong enough to trigger the mechanical opening of the nozzle, but at the same time sufficient to satisfy the diagnostic checks carried out by the petrol ECU.

Ultimately, the invention considered according to the form illustrated in Fig. 10 reveals an unprecedented electronic solution which, in addition to the symmetrical architecture without the need for polarity in the electrical connections, also makes use of the switching technique. This characterizes a petrol injector emulator device E having superior and absolutely original performances compared to all the other devices known today on the market, which have the polarity constraint in the electrical connections, use passive components with impedance Z and do not use the circuit. active A of the switching technique considered here.

Finally, it should be noted that the device according to the invention is fully suitable and compatible for the generality of the current uses for which it is intended, because it can be applied independently of:

â € ¢ type and number of petrol injectors on the engine;

â € ¢ type and number of alternative fuel injectors;

â € ¢ type of injector control exercised by the petrol ECU;

â € ¢ type of injector control exercised by the control unit for alternative fuel;

â € ¢ physical state, liquid or gaseous, in which the alternative fuel is at the time of injection into the engine;

â € ¢ type of system installed;

â € ¢ level of integration, partial or total, of the petrol injector emulator device inside the control unit for alternative fuel;

â € ¢ installation method of the petrol injector emulator device. - -

Claims (12)

CLAIMS 1. Electronic device, for the injection system of two or more fuels in internal combustion engines, capable of inhibiting the injectors of a first fuel, usually petrol, and at the same time emulating their normal operation in order not to create an undesired alarm in the diagnostic systems of the original electronic control unit, characterized by the fact of having a symmetrical architecture of its own electrical circuit (E), which consists of two equal groups, where a first group contains at least a first transistor (T) with its own diode (Jâ € ™) and its own impedance (Z) connected in parallel, while a second group contains at least a second transistor (Tâ €) with its own diode (Jâ €) and its own impedance (Zâ €) connected in parallel, and said two groups are connected in series and symmetrically to each other, so that the complex formed by them is also symmetrical, and said complex is also connected in parallel to the contact (K) of a relay ̈ (R) and to an impedance (Z) or to an active circuit (A) in switching technique, so that the whole circuit thus formed is still symmetrical, and in the central point of the symmetry, i.e. where the two transistors (Τ ', Tâ €) are joined, a sensor (S) is applied which detects the electrical signal generated by the driver (D) to control the injectors (B); so that the connections (L, L ") of said electrical circuit (E) with the injector (B) and with the driver (D) can also be reversed, without the need to respect the polarity of the electrical connections. 2. Electronic device, according to the preceding claim, characterized in that the electric circuit (E) for emulating the petrol injector (B) performs the multiple function of: reducing the current circulating in the petrol injector (B) to prevent it the opening of the nozzle, emulate the normal operation of the petrol injector (B) in such a way that the original control unit (C) does not notice it, increase the current circulating in the petrol injector (B) to make it open the nozzle by means of an electronic control applied to the transistors (Τ ', Tâ €) in order to power the engine by dosing together both the original fuel flow and the alternative fuel flow, making installation easier and safer without no need to pay attention to the polarization of the electrical connections facing the petrol injector (B) and the driver (D), to reduce the consumption of electricity required and the effect of d thermal emission thanks to the use of the active circuit (A) based on the switching technique. 3. Electronic device, according to the preceding claims, characterized by a circuit functioning correctly even with reverse polarity applied to its electrical connections (Lâ € ™, Lâ €) made with the petrol injector (B) and with the driver (D ), regardless of the installation method, whether it uses free solder wires or connectors, which can also be the simplest, single-pole type and without references or constraints that predetermine a specific connection in relation to the polarization. 4. Electronic device, according to the preceding claims, characterized in that it exploits the switching power supply technique to manage and control the current circulating on the petrol injector (B). 5. Electronic device, according to the preceding claims, characterized by the fact of exploiting the switching technique for the management and control of the current circulating on the petrol injectors (B) regardless of the polarity applied to its electrical connections (Lâ € ™, Lâ €) practiced with the petrol injector (B) and with the driver (D). 6. Electronic device, according to the preceding claims, characterized in that it exploits the switching technique for the management and control of the current circulating on the petrol injectors (B) regardless of the technology and type of circuit adopted for the recirculation current. 7. Electronic device, according to the preceding claims, characterized in that it allows the metered and modulated flow of the fuel at will, both of a single type and of several types, even simultaneously, in a differentiated, progressive, regressive, alternating, sequential manner, etc. , according to commands appropriately given by the electronic control unit, in manual, semiautomatic or automatic mode, also on the basis of specific computerized programs. 8. Electronic device, according to the preceding claims, characterized by the fact that it can also be applied to pre-existing engine fuel systems operating with fuel injection into the cylinders, maintaining total compatibility regardless of the type of injection system, both with direct injection and indirect injection , regardless of the number and type of injectors, regardless of the number and type of engine cylinders. 9. Electronic device, according to the preceding claims, characterized by the fact that it maintains correct performance regardless of the nature of the alternative fuel used, which can be methane, LPG or other, and regardless of the physical state, liquid or gaseous, assumed by it at the time injection in the engine. 10. Electronic device, according to the preceding claims, characterized by the fact of r be applicable also as a single unit, i.e. regardless of the level of integration, total or partial, of the device itself, in the alternative fuel control unit (G), and independently of the single or joint implementation of all the possible combinations of the technological solutions and performance mentioned above. 11. Electronic device, according to the preceding claims, characterized in that it uses a new original method of exploiting the switching power supply technique which involves high efficiency and less waste of thermal energy to be dissipated, allowing a push to miniaturize the device itself. 12. Electronic device, according to the preceding claims, characterized by the fact both of obeying electronic signals, by means of commands to the transistors (Τ ', Tâ €) and by means of commands to the active circuit (A), and of generating electronic signals, through the sensor (S) that reads the voltage caused by the driver (D) or also through other sensors that read other useful parameters such as the temperature, etc. where said sensors (S) remain operational regardless of the polarization applied to the device, being connected to a symmetry point of the electronic circuit (E), obtained at and