WO1992007186A1

WO1992007186A1 - Spark phase changing device for endothermic engines

Info

Publication number: WO1992007186A1
Application number: PCT/IT1991/000065
Authority: WO
Inventors: Astorre Biondi; Gianni Regazzi
Original assignee: Ducati Energia S.P.A.
Priority date: 1990-10-18
Filing date: 1991-07-24
Publication date: 1992-04-30
Also published as: IT9083502A0; AU8317791A; IT9083502A1; IT1242661B

Abstract

A spark phase change device for endothermic engines, including at least: phase sensor means related to a certain angular position of the engine shaft 'PV': an ignition group 'CD', timer means 'Tz1, Tz2' directly or indirectly operated or controlled by said phase sensor means 'PV'; an interruption means of the electric circuit 'SW' operated or controlled by said timer means 'Tz1' and by said phase sensor means 'PV'; shunting means 'D1' of said timer means 'Tz2'; logic operation means 'OR-I1' operated by said electric circuit interruption means 'SW' and by said shunting means 'D1', characterized in that the change of the phase is carried out by a first gradual changing phase included in the time of the signal of the phase sensor 'PV' controlled by said timer means 'Tz1' that operate the interruption means of the electric circuit 'SW'.

Description

DESCRIPTION

SPARK PHASE CHANGING DEVICE FOR ENDOTHERMIC ENGINES

The object of the present invention is a spark phase changing device for endolhermic engines.

The present invention concerns a device and its relevant changing method for the very right ignition phase for power limitation and consequent limitation of the rotation speed of endothermic engines.

At the moment such devices are planned to limit the power of the motors by simply eliminating the spark and deriving pollution from unburnt gas. Furthermore they are frequently executed with analogical type circuits that delay the intervention reducing in that way preciseness. The aim of the present invention is to obviate the above-mentioned drawbacks without increasing the cost of the device. This and other scopes are reached with the present invention as claimed by using a digital planned circuit with a spark phase change device including at least: - phase sensor means related to certain angular position of the engine shaft; - an ignition group; - timing means directly or indirectly operated or controlled by the phase sensor means; - electric circuit cut-off means, cutting off circuits from timing means and from phase sensor means controlled by the timing means themselves; - shunting means of the timing means - control and logic selection means operated by the electric circuit cut-off means by the shunting means; characterized in that the change of phase is carried out by a first gradual change phase taking place during the signal time of the phase sensor "PV" controlled by said timing means which control the cut-off means of the electric circuit. We get to the change in a favorable way by means of a second step- phase change, controlled by a second timer from the end of the signal of the phase sensor. Advantageously the phase change of the spark takes place starting from a rotation speed of the endothermic engine, which is selectable on the grounds of the lime fixed on the first timer. Advantageously the type of step-phase change is selectable on the grounds of the time fixed on the second timer. Advantageously the operation of the ignition group is made by means of a logic electronic device "OR" which input signals are sent respectively by the electronic switch operated by the first timer by means of a respective signal and by a shunter controlled by the second timer by means of a respective signal, and in which the first timer and second timer are synchronized with the exit signal of the phase sensor "PV", and in which the second timer is preset by said first timer only for angular speeds higher than a maximum prefixed value. In this way we get a fast and gradual delay of the ignition phase which causes a diminution of the engine power and of the relevant rotation speed without generating unburnt gas because the spark is always present at the plug. Furthermore generating the command impulse (for engine revolution) in real time, the angular intervention speed of the device does not undergo delays depending on the electric circuit therefore and therefore becomes very precise even with a high dynamic state of the angular speed (strong accelerations). This solution is therefore suitable for speed limits as to the law in force and as to the marine applications where the runaway speed of the engines are very dangerous for the integrity of the engine itself. The device can however be used in many other applications. The invention is clearer referring to the following description and relevant drawings supplied only as example, in which: - Fig. 1 represents a block scheme of the system where the device according to present invention makes part of the outlined zone; - Fig. 2 represents a phase diagram of the signals indicated in Fig.l; - Fig. 3 represents a typical state of the change of the spark phase determined by the device. With reference to the Figures and according to what claimed the invention regards a change device of the spark phase including: - a phase sensor related to a special angular position of the engine shaft "PV"; - an ignition group "CD"; - a first timer "Tzl" operated by a phase sensor "PV"; - a second timer "Tz2" preset by the first timer "Tzl" and operated by the phase sensor "PV"; - an electronic switch "SW" controlled by said first timer "Trl"; - a shunter "Dl" for said second timer "Tz2"; - a logic element "OR" operated by the "SW" switch and by the shunter "Dl "; wherein the change of the phase takes place in two times and in very different ways but always being synchronized with the angular signal of the PV sensor . The first change is controlled by the "Tzl" timer with the help of the "SW" switch. It is gradual and inserted in the signal time of the phase sensor "PV" while the second is operated by the "Tz2" timer by means of the "Dl " shunter and it is a jump of phase which is proportional to the duration of "Tz2" but always linked to the phase shunted from the angular position of the motor or from the "PV" phase sensor. The logic element "OR" has has been assigned to send to the ignition group "CD" the logic sum of the two signals coming from the shunter "CD" of the electronic switch "SW". In particular : Figure 2 represents the comparison between the times in which the signal operates in all the various positions of the circuit according to the present invention and indicated in Figure 1 with: "A" below the phase detector "PV"; "B" below the first timer "TZ1"; "C" below the second timer "TZ2"; "D" below the differentiator element "Dl "; "E" below the " electronic switch "SW"; "F" below the logic element "OR"; "G" below the ignition group "CD" and over the ignition plug "AT". The phase changing device refers to an angular ω A speed value which can be programmed by the timer Tzl. The latter is commanded on the front terminal of the phase signal "A Fig.2". For "ω" angular speeds lower than "ωa", the time tpl due for "Tzl" is lower than the time Tl which entity depends on the phase sensor "PV" "A Fig. 2". This situation, along with the fact that the switch "SW" is closed when Tpl is inactive, allows the signal coming from the angular position of the engine shaft and also from the phase sensor "PV" to reach the ignition group "CD" going across the logic element "OR" "II". In this way the spark strikes on the the first front of "PV" with the angle phase which represents the angular reference of the engine shaft. As a result : • For angular speeds lower than intervention speed "ω < ωa" the device acts transparently for the ignition in order to permit a conventional way of operation. With reference to fig.1 , the path of the signal is: PV. A. SW, E, I1, F, G • For angular speeds ω higher than ω a the device enters in the gradual phase displacement area of the spark compared to the first front supplied by the signal of the phase sensor "PV". In this work area "tpl " due to "Tzl " it ends inside the signal "A" of "PV" because it is greater than "T2" or "T3". In this situation the electronic switch "SW" is open during the starting front "A" of "PV" not permitting in such a way any passage until "ω2" or "ω3" gets closed. At this point the electronic switch "SW" gets closed and the passage of signal "A" deriving from sensor "PV" by means of the logic device "OR-I1" gets recycled just up to the ignition group "CD". Therefore we obtain a changing phase "α2" and "α3" which entity depends on the the temporal difference between the end of "tpl" and the end of "T2" or "T3". Such difference is represented at points "ω2" and "ω3" respectively by "α2" and "α3". For "ω " angular speeds higher than "ω b" "ω " > "cob" the gradual displacement phase function gets finished while the release or "step" displacement phase takes over. This happens when the lime of the signal "A" of "PV" "T2" + "T3" is lower than the time tpl of "Tzl". In this circumstance the signal of "Tzl" is always activated therefore keeping the electronic switch "SW" open. The switch inhibits the signal "A" of the phase sensor "PV" up to the ignition group "CD". In these conditions "Tz2" gets preset and being controlled by the phase sensor "PV" it sends a "Tp2" signal which time represents the phase difference between "α4" and "α5" indicated at the angular speed "ω4". To obtain such phase release displacement the corresponding "D"signal gets shunted from the differentiator element "Dl". The signal "D" corresponds to the conclusive front of "tp2" which gets to ignition "CD" through the logic element "OR" - "II". The path of the signal is therefore the following: PV, A, Tz2, C, D1, D, I1, F, CD, G.

Claims

CLAIMS 1 A spark phase change device for endothermic engines, including at least - phase sensor means related to a certain angular position of the engine shaft "PV"; - an ignition group "CD", - timer means"Tzl,Tz2" directly or indirectly operated or controlled by said phase sensor mcans' V"; - an interruption means of the electric circuit "SW" operated or controlled by said timer means' zl " and by said phase sensor means"PV"; - shunting means"Dl" of said timer means"Tz2"; - logic operation means"OR-Il" operated by said electric circuit interruption means"SW" and by said shunting means"Dl"; characterized in that the change of the phase is carried out by a first gradual changing phase included in the time of the signal of the phase sensor "PV" controlled by said timer means "Tzl" that operate the interruption means of the electric circuit "SW". - a second timer means "Tz2" preset by the first timer means "Tzl" and operated by the phase sensor "PV";

2. A spark phase changing device for endothermic engines according to claim 1 including: - a phase sensor in relation with a certain angular position of the engine shaft "PV"; - an ignition group "CD": - a first timer means "Tzl" operated by a phase sensor "PV"; - a second timer means "Tz2" preset by the first timer means "Tzl" and operated by the phase sensor "PV"; - an electronic switch "SW" controlled by the first timer means "Trl "; - a shunter "Dl" for the second timer means "Tz2"; - a logic element "OR" operated by the electronic switch "SW" and by the shunter"Dl "; characterized in that the change in phase takes place in two times and different ways but always synchronized with the angular signal of the "PV" sensor ; • a first gradual change of phase taking place during the signal time of said phase ^"sensor "PV" controlled by the first timer means "Tzl" that commands the electronic switch "SW"; -- a second "step" change of phase controlled by the second timer means "Tz2" starting from the end of the signal of the "PV" phase sensor.

3 A spark phase change device for endothermic engines according to claim 1., characterized in that the phase change of the spark takes place starting from a rotation speed of the selectable endothermic engine on the grounds of the time fixed on the first timer means "Tzl".

4. A spark phase change device for endothermic engines according to claim 1., characterized in that the entity of the "step" phase change is selectable on the grounds of the time fixed on the second timer "Tz2".

5. Spark phase change device for endothermic engines according to claim 1., characterized in that the command "F" of the ignition group is sent through a logic electronic device "OR" which input signals "E,D" arc sent respectively by the electronic switch "SW" operated by the first timer "Tzl " by means of a respective signal "B" and by a shunter "Dl " operated by said second timer means "Tz2" through a respective signal "C", and in which the first timer means "Tzl" and second timer means "Tz2" are synchronized with the exit signal "A" of ihc phase sensor "PV" and in which said second timer means "Tz2" is preset by said first timer means "Tzl " only for angular speeds "ω " higher than the preset maximum value "ωb " .