METHOD AND DEVICES TO IDENTIFY THE PHASE IN AN INTERNAL COMBUSTION ENGINE

Technical field

The present invention relates to a method and devices therefor for phase identification in an internal combustion engine, in particular for identifying which cylinder thereof is in the compression phase. Background Art

The methods and devices currently utilised and available on the market for phase identification in an internal combustion engine, in particular for identifying which cylinder thereof is in the compression phase, are based on the use of sensors positioned on the cam shaft. This known method has various drawbacks. The most relevant drawbacks are constituted of possible sensor functioning failure. A further method is likewise known for phase identification in of an internal combustion engine which involves forcing combustion failure. This method is based on the failure of the mixture ignition in a determined cylinder.

The said method presents the drawback that it determines an anomalous functioning of the said internal combustion engine with damaging effects for the said engine and for the functioning of the vehicle in which the said engine is mounted. Disclosure of Invention

The aim of the present invention is to identify a method, and the devices therefor, for identifying, in an accurate and reliable manner, which cylinder of an internal combustion engine is in the

compression phase, thereby overcoming the drawbacks of the known methods and devices.

The present invention makes advantageous use of the ionisation current developed during the combustion of the mixture in each cylinder of an internal combustion engine.

This ionisation current is measured by a Control Unit (4), commonly used for the management of the said internal combustion engines. The aims and advantages will better emerge in the description that follows and the plates enclosed, which illustrate, purely in the form of a non-limiting example, an internal combustion engine with a plurality of cylinders: figure 1 illustrates a schematic view of an engine which utilises the method, and the Control Unit in which the means that actuate the invention in question are housed (the said means are not shown graphically); figure 2 illustrates the part of the device in question in the present invention, located on top of the cylinders which, in addition to creating the spark necessary to realise the combustion inside the cylinder, produces the ionisation current indispensable for actuating the method in question; figure 3 illustrates, schematically, the flow chart relating to the method according to the invention in question.

With reference to figure 1, (1) indicates an internal combustion engine as a whole, fitted with one or more cylinders (2), one or more pistons (3), a device (5) positioned on top of each cylinder which, in addition to creating - by means of the spark plug - the spark necessary to realise the combustion inside the cylinder, releases the ionisation current, which is indispensable to actuate the method in question. This figure also shows

a Control Unit (4). The devices for actuating the method (not shown graphically) likewise are positioned in the said Control Unit. With reference to figure 2, the said figure indicates the part of the device in question in the invention, positioned on top of the cylinders which, in addition to creating the spark necessary to realise the combustion inside the engine, produces the ionisation current, which is indispensable to implement the method in question. This part of the device is constituted of a coil (6) and a spark plug (9). The coil (6) is fitted with a primary circuit (7) and a secondary circuit (8). The two elements (5) and (9) are mutually connected by a polarisation circuit (10) and an acquisition circuit (11).

With reference to figure 3, the said figure indicates a flow chart which schematically illustrates the method in question in the invention. This method develops over various phases, to each of which the electronic device therefor corresponds, the said device being identified with the same reference number as the respective number of the method phase. In a first phase (300) the fuel is admitted to each cylinder (2) of the internal combustion engine (1). In the following phase of the method (301), in which the engine begins to function and completes the first cycle, the spark plug (9) causes a spark in each cylinder (2) whose piston (3) is located at the top dead centre.

In phase (302) the registration is effected, from the end of the spark produced by the spark plug (9) - as mentioned in the previous phase - of the ionisation current (IC) signals produced in the secondary circuit (8) of the device (5) of each cylinder (2) whose piston (3) is at the top dead centre. These signals are called, in the present invention, (S).

The method continues with a subsequent phase (303) consisting of the calculation of the average value of the signals S produced during the previous phase (302). This average value is called, in the present invention, VmS. The subsequent phase (304) of the method relates to the comparison of the average value VmS registered in the previous phase (303) and a predetermined value, called in the present invention, V. The method concludes with phase 305. In the said phase, each cylinder (2) of the internal combustion engine (1) in which the average value VmS is greater than the predetermined value V is identified. In conventional engines, the cylinder identified in the said phase (305) is the sole cylinder which is in the compression phase. The description above and the tables enclosed illustrate an embodiment of the present invention and constitute a non-limiting example thereof within the scope of protection of the claims that follow.