ITCT20080016A1 - ELECTROMAGNETIC DISTRIBUTION SYSTEM FOR VARIABLE ACTIVATION OF VALVES IN MCI - Google Patents

Description

SUMMARY of the industrial invention having the TITLE:

"Electromametic distribution system Der the variable actuation of valves in MCI",

SUMMARY

The device in question? an electromagnetic servomechanism for the actuation of the variable actuation of the valves in Internal Combustion Engines. Compared to the usual distribution systems, the proposed solution has the following advantages.

./ Elimination of mechanical components belonging to the classic distribution mechanisms with consequent reduction of weight and dimensions and of the height of the center of gravity of the MCI (for example camshaft, pulleys and / or gears and control belts, tappets, cups, etc. )

./ Total flexibility in controlling the law of motion of each single valve (easy timing variation according to engine speed and load)

./ Optimization of filling of each single cylinder with consequent increase in torque and power over the entire engine speed range

./ Generation of turbulence in the cylinder by playing on the different laws of motion of the two intake valves (combustion optimization)

./ Possibility? to realize a modular operation of the motor by excluding at partial loads one or more? cylinders minimizing consumption

./ Simplicity construction of the assembly with relatively low costs

The system can? therefore to find practical application both for the increase of the performances, and for the containment of consumptions and noxious emissions to the exhaust of the MC !.

DESCRIPTION of the industrial invention with TITLE:

"Electromametic distribution system for variable actuation of valves in MCI",

DESCRIPTION

The device ? It has been designed to allow the operation of each single valve in Internal Combustion Engines regardless of the lift law of all the other valves, by means of an electric command coming from a relative management circuit.

The system ? represented in Table 1; the parts making up the actuating servomechanism are indicated below.

The device is based on the use of a series magnetic circuit consisting of:

- / a Permanent Magnet (responsible for the development of mechanical strength) bound to a suitable sealing cover

./ an anchor (high magnetic permeability core) connected with forced coupling to the valve stem, also having the function of a plate for the transfer of the reaction thrusts of the contrast springs to the valve ./ a winding of Magneto-Driving Force coaxial to the ferromagnetic core. / a Magneto-Rheological fluid with permeability? magnetic pi? of the air commonly used in normal magnetic circuits as an air gap.

Under normal conditions (absence of current in the FMM winding) the magnetic field generated by the MP induces high permeability in the core? a magnetic field of the same direction as the magnet, so that? the overall mechanical force (deriving from the equilibrium obtained considering also the elastic reactions of the springs) acting on the anchor? attractiveness, and the valve remains closed. The function of the winding of FMM lies in the inversion of the mechanical force through the passage of current in the turns of the coil, wound in such a way as to generate in the area of the core with high permeability? a magnetic field having the opposite direction to the MP field, causing the valve to open; the start and maintenance times of the winding power supply depend on the engine speed and load. By removing power from the FMM winding. thanks to the calibration of the preloads and the stiffness of the contrast springs, the valve returns to its seat with a mirror motion law with respect to the opening phase. The use of an MR fluid instead of air allows to minimize the reluctance of the air gap allowing to have a little variable mechanical force acting on the valve, passing from the condition of minimum air gap (valve closed) to that of maximum air gap (max lift). The presence of an MP in the circuit? instead it causes a high base reluctance but also an equally high FMMMP due to the product of the intrinsic coercive force of the MP by its length.

This solution has the characteristic of making the time constant of the electrical circuit negligible (transient response) ensuring excellent performance in terms of force development.

The unreliability of the device from possible valve-valve and valve-piston collisions is eliminated by means of an appropriate design of the combustion chamber (roof) and by making suitably deep slots in the piston crown.

The use of a phonic wheel keyed on the crankshaft in an angular reference position (for example the Top Dead Center in cylinders l and 4 in an in-line four-cylinder) allows the position and speed sensors angular to obtain the information respectively in terms of e and ro necessary for the electronic control unit together with the position of the accelerator pedal, to give the command (FMM winding power supply) to each individual valve.

The rough sizing of the device carried out to meet the specifications of a two-liter four-cylinder in-line 16-valve (Stroke! Bore = l) with compression ignition with maximum speed of 4000 rpm, has allowed us to obtain the following data and performances.

Dimensions R and A are indicated in Table 2, while Tables 3 and 4 refer to the possible practical application indicated above.

Claims (1)

CLAIMS of the industrial invention having as TITLE: "Electromametic distribution system for variable actuation of valves in MCI", CLAIMS l) Shape and geometry of the entire distribution system 2) Shape and geometry of the single actuating servomechanism Geometric shape of the following components. 3) Ferromagnetic core 17 4) Permanent Magnet 19 New applications of materials and solutions. 5) Use of Magneto-Rheological fluid instead of air as air gap 6) Magneto-Rheological Fluid made using highly brushed metal glass particles? magnetic 7) Use of a Pennanent Magnet for the generation of repulsive force 8) Use of a winding of FMM for the inversion of the direction of the force 9) Electromagnetic circuit as a whole (unipolar configuration) 10) Use of an electromagnetic servomechanism for actuating the valves in Internal Combustion Engines.