AU728291B2 - Simulation device for disconnecting injectors in motor vehicles - Google Patents

Description

S F Ref: 426073

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: A.E.B. S.r.l.

Via dell'Industria, Zona Ind. Corte Tegge 42025 Cavriago (RE)

ITALY

Ivan Paterlini and Vincenzo Baroni Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Simulation Device for Disconnecting Injectors in Motor Vehicles a.* The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845 SIMULATION DEVICE FOR DISCONNECTING INJECTORS IN MOTOR

VEHICLES

DESCRIPTION

The present invention relates to a simulation device for disconnecting injectors in motor vehicles.

The invention is used in vehicles with an internal combustion engine having an injection system fed by two different sources (for example petrol and gas). One of the problems which arises when changing over from a petrol feed system to a feed system using methane gas or LPG (or other fuels) is that, when the petrol injectors are disconnected and the petrol flow interrupted, the electronic injection control unit detects incorrect operation of the injectors or detects that they are not active, signalling malfunctioning thereof, even if the injectors are disconnected intentionally.

S -10 The known art, in order to solve this problem, has developed simulation devices, namely devices which simulate the active presence of the injectors even when they are :-os.deactivated.

Said simulation devices provide, for example, for each injector, a voltage which is the S. same as that which the control unit detected during correct operation of the injector itself.

15 One drawback of these devices lies in the fact that it is necessary to determine the correct polarity (positive pole and negative pole) upon installation and it is necessary to have in stock two types of simulators, called a right-hand and left-hand simulator depending on Sthe position of the positive pole, so that they can be mounted on all types of injection vehicles.

A further drawback consists in the fact that, owing to their design, they require cutting of the original wiring with a consequent potential invalidation of the guarantee covering the original feed system of the vehicle, if it is a new vehicle which is still under guarantee.

In order to overcome these drawbacks, recently simulation devices have been developed, said devices consisting essentially of a resistor which is arranged between the injector and the injection control unit and has the function of reducing the current flow so as to ensure that the injector is kept at the operating voltage, but is supplied by a current which is insufficient to cause it to operate.

In this Way an additional reference voltage source is not required and the problems associated with installation of the device due to possible inversion of polarity are also eliminated.

However, in some control units of the more advanced type, it is necessary to provide a current which is higher, i.e. sufficiently high to deceive the control unit, but at the same time sufficiently low to keep the injector deactivated.

For this reason it is nevertheless required to have in stock various types of simulators which differ from one another in terms of the ohmic value of the resistor contained therein.

Object of the Invention It is an object of the present invention to overcome or ameliorate some of the disadvantages of the prior art, or at least to provide a useful alternative.

2Summary of the Invention 20 There is firstly disclosed herein a simulation device for disconnecting injectors in motor vehicles, of the type mounted between an injection control unit and injectors, characterized in that it comprises internally at least one resistor unit with a variable resistance value for simulating different load values.

2.The present invention, at least in a preferred embodiment, provides a device which is universal, namely can be applied to all injection vehicles whatever type of control unit they use, which allows simulation of the injectors during operation of the vehicle with a gas feed system, by means of simple limitation of the value of the electric current without interrupting the injector circuit and without therefore activating an alternative path in order to simulate its load.

30 The present invention further preferably provides a device particularly simple and low-cost and easy to fit, without the need for cutting any of the original wiring.

The present invention, still further preferably comprises internally at least one variable-resistance resistor unit, which allows different load values to be simulated. The resistor unit may consist, for example, of two or more resistors with a different resistance value which can be selected individually, or may consist of two or more resistors which can be connected in parallel or in series so as to vary the overall resistance value of the resistor unit, or may consist of a simple variable-resistance or rheostat.

Preferably an external actuating device is present, in the form of a microswitch with two or more positions, for varying directly the resistance value of the resistor unit, by activating for example a secondary resistor in parallel with a main resistor or by activating selectively individual resistors of varying resistance value.

Brief Description of the Drawings A preferred form of the present invention will now be described by way of example only with reference to the acconpanying drawings wherein: l0 Figure 1 shows an electrical block diagram of the device; Figure 2 illustrates schematically application of the device; and Figure 3 shows a variation of embodiment of a circuit part of the device.

Detailed Description of the Preferred Embodiments With reference to the figures, 1 denotes in its entirety a preferred simulation device enclosed in a box-type casing 1 a of the known type.

The device may comprise an external trimmer 2 by means of which it is possible to adjust a command unit 2a for regulating the fuel overlap time (where necessary) in order to avoid supply voids which may cause flashback. The trimmer is calibrated during testing, but may also be used for subsequent adjustment.

20 The device 1 may be installed in the passenger compartment, in the boot space, oooo or outside the vehicle, in the engine compartment or on the drive system and may be installed or contained also inside other more complex devices or equipment, such as for example a carburation and/or gas injection control unit.

o*o• ooooo3 4 3 denotes the individual simulation groups, only one of which is shown in greater detail and each of which is connected to a corresponding injector 4. The number of groups 3 is normally equivalent to the number of injectors, but there may be a single simulation group connected to a single injector (in the case of single-point injection) or to several injectors (in the case of multi-point injection).

Each simulation group comprises an activation relay 5 and a resistor unit 6.

When the relay 5 is closed, the resistance circuit of the simulation group is disabled, whereas when the relay is open the present device is activated aihd consequently the injectors deactivated. This represents a safety condition because, in the event of malfunctions, the closed condition of the relay ensures exclusion of the device.

The relay is activated by the command unit 2a which is operated by the vehicle driver by means of an actuating member (switch member) of the known type situated inside the passenger compartment.

The relay 5 may be replaced by an active component such as, for example, a MOSFET.

15 The resistor unit 6 comprises a plurality of resistors 7 arranged in parallel (as shown in Figure 1) or in series, called R0, R, but may also comprise a variable resistor or rheostat °The resistors in parallel are configured with a resistor Ro always selected and one or more resistors in parallel R, Rn which can be selected individually or in a group, as in 20 Figure 1, by means of respective selectors 8 called in order to reduce the overall °o resistance value of the resistor unit, in accordance with Ohm's law. It is obvious that, in the case of resistors in series, the total resistance value will be determined instead by the sum of the individual resistance values.

According to a variation of embodiment illustrated in Figure 3, the resistors R 0 R, Rn may be configured in such a way that they can be selected individually by means of S i, a single multiple-position load selector 8.

In this case the resistance value of the resistor unit coincides with the resistance value of the resistor selected.

The selectors 8 are of the type which can be operated manually from the outside upon installation of the device.

This is achieved by designing the selectors 8 as microswitches or movable jumpers which are intended to connect selectively the resistors 7 by means of the connection of selected pins, so as to close the circuit between an injection control unit 9 and the injectors 4.

However, it is possible to envisage automatic selection of the resistors 7: the device detects the self-diagnosis output signal of the control unit 9 which signals an error or malfunction situation, after which it varies the load (or the resistance value) until it detects several malfunction signals of the control unit 9.

S"The present device is installed between the injection control unit 9 and the injectors 4 and .is provided with connectors 10 such that each input connector 1 Oa of the device is coupled 15 with a corresponding output connector 11 of the control unit, while each output connector of the device is coupled with a corresponding input connector 12 of each injector.

In this way the device is inserted between injection control unit 9 and injectors 4 without •.cutting any of the existing wiring.

The present invention continues to function correctly even after 50,000 simulation cycles, •20 without the need for periodic checks.

i At the moment of installation of the device, depending on the load value required by the vehicle control unit, the load needed is correspondingly set in the device by operating the external actuating device (multiple switch, multiple relay or connector with movable jumper).

Selection and setting of the load value to be activated in series with the injector circuit, however, may also be performed automatically by means of detection of suitable signals from the control unit, as already described above.

At this stage the device is ready for operation and does not require further calibration, nor periodic calibration, and is universal, being able to be applied to all the commercially available control units, since the resistance value may be varied.

The choice of the resistance value depends not on the type of vehicle, but on the type of control unit mounted on the vehicle.

Deactivation of the injectors, during operation with gas, is performed without the need to determine the polarity of said injectors, using a single device of the universal type which can be easily installed on all the injection control units and which allows a variable resistor to be activated such that a current insufficient to cause activation of the injectors passes into the injector circuit.

This has the purpose of deactivating the petrol injectors and sending to the electronic ~injection control unit of the vehicle a signal such that the disabled condition of the 0 15 injectors is not detected as being a malfunction by the same control unit.

Installation of the device is performed without the need to identify the polarity of the injectors and without cutting any original wiring and therefore without invalidating the vehicle guarantee.

020

Claims (11)

1. Simulation device for disconnecting injectors in motor vehicles, of the type mounted between an injection control unit and injectors characterized in that it comprises internally at least one resistor unit with a variable resistance value for simulating different load values.

2. Device according to Claim 1, in which each resistor unit consists of a rheostat.

3. Device according to Claim 1, in which each resistor unit comprises a plurality of resistors which are connected in parallel and one or more selectors for selecting one or more of said resistors so that the resistance value of the resistance unit depends on the resistors selected, in accordance with Ohm's law on the resistors in parallel.

4. Device according to Claim 1, in which each resistor unit comprises a plurality of resistors connected in series or one more selectors for selecting one or more of said resistors so that the resistance value of the resistance unit depends on the resistors selected in accordance with Ohm's law. Device according to Claim in which each resistor unit comprises a plurality of 1 .e resistors and a puorr o *resistors and a selector by meansof which the resistor with the desired resistance value is selected.

S

6. Device according to Claims 3, 4 or 5, in which each selector nss of a ov Jumper which closes the circuit between the control unit and the injectors by u selecting a resistor. ,m consists of a microswitch

7. Device according to Claim 3 or 4, in which each selector w consists tfa microswitch.

8. Device according to Claim 5, in which the selector consists of a multiple-position microswitch.

9. Device according to Claim 3, in which the selectors r activatd automatic wit etin of he load vle (or rince vale) to are activated automatically, with setting of the load value (or resistance value) to be activated in series with the injector An RALie wihteijco circuit being performed by means of detection of self-diagnosis output signals of the control unit.

Electronic apparatus for motor vehicles, characterized in that it comprises a device according to any one of the preceding claims.

11. Simulation device for disconnecting injectors in motor vehicles, substantially as described herein in relation to any one of the embodiments with reference to the accompanying drawings. to Dated 31 October, 2000 A.E.B. S.r.l. Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON 0* *00* 0 0 0 *ooo 0 0 [R:\LIBM]39027.doc:lzg