Apperò lotus.. che bel motore

[85kimeruccio]

signed a licensing agreement with the North American tier one supplier Eaton Automotive to develop for production Active Valve Train (AVT) system has focussed attention on what is colloquially called the "camless engine". Simon Wood, director of Lotus Engineering, has described the agreement as being "important for both companies." AVT is Lotus Engineering's version of the Fully Variable Valve Train (FVVT). It is said to offer a level of valve control not seen so far in production engines.

The use of electro-hydraulic valve actuation technology enables the camshaft to be replaced by lighter and more compact hardware. This enables virtually infinite manipulation of the timing, duration and extent of lift for each valve. The complex control system selects and implements the valve lift profile that achieves optimal operational efficiency across the engine's entire speed and load range. "At the end of the day though," says James Turner, Lotus's Senior Technical Specialist, Powertrain Research, "it is just control of an actuator." AVT, in fact, has its origins in the fast actuation systems used in Lotus's work on active suspension systems.

Lotus has been working on AVT since 1992. It was originally used as a single cylinder research tool to look at the relative merits of port- versus valve-deactivation, similar to Honda VTEC-E engines and rapid evaluation of cam profiles. It has also been used to investigate Mechanical Variable Valvetrain (MVVT) like the BMW Valvetronic. The AVT system is enclosed in a cassette sitting atop of the engine. Contained within the cassette are a digital three-way valve, control coil, integral displacement transducer and actuating piston.

The company has since sold 15 AVT research engines to vehicle manufacturers and tier one suppliers mainly for the significant savings in testing time resulting from the ease of changing valve profiles. The power of AVT in research has assisted Lotus to become a leading company in Controlled Auto Ignition (CAI) research, experimentation into CAI having commenced in 1998.

Lotus and Eaton will be working together to meet the cost, packaging and performance requirements of a production system. One essential feature will be to develop an inexpensive alternative to the MOOG valves currently being used in the research system and which cost around 5,700-7,000 Euro each.

Eaton aims to have demonstration vehicles on the road within two years and is planning to put AVT into volume production by 2008 although this very much depends upon industry pressures. However, an undisclosed major European vehicle manufacturer has already signed an agreement to acquire the AVT system for one of its platforms.

Lotus Engineering's Head of Sales John Moore points out that virtually all of the company's major clients are working actively on "camless" technology. It is thought that the first FVVT to reach the market will be an electro-magnetic system. Lotus contends that the electro-hydraulic systems that are being developed, both with and without positional feedback control, will be superior in that the have the possibility to vary valve lift. This is something not easily achievable with the electro-magnetic "catch and hold" approach. It is therefore more difficult for them to realise all of the possible benefits of improved combustion be promised by electro-hydraulic systems. "A variable lift is the end game from a combustion point of view," says Turner.

The first AVT engines that appear in production will probably differ little from mechanical systems. However, there are said to be huge possibilities in the use of this technology. Each cylinder in the engine can be though of as a single cylinder head, the crank speed the only thing that they have to share. Every combustion event can be viewed as a separate event with the aim being to make every combustion event controllable.

Lotus sees the AVT system as being an essential enabler for new combustion processes. It has, for example, demonstrated that Controlled Auto Ignition (CAI) and Homogenous Charge Compression Ignition (HCCI) are capable of reducing engine-out nitrogen oxides (NOx) emissions by up to 98%.

The benefits that AVT brings include not only reduced emissions and fuel consumption but also increased torque and power output potential. Simulations show that for a conventional baseline engine, the improved operational efficiency increases torque by up to 10%. This kind of valve train can also give a massive increase to the performance of diesel engines. An almost incidental benefit is that there is no need for any engine oil in the head anymore. The fact that the engine can be started on one cylinder also means than the starter motor and battery can be downsized. "There so many things that you can achieve once you have flexibility of control," says Turner.


da quel che ho capito questo sembrerebbe un sistema di attuazione delle valvole senza albero a camme.

niente male!! vedo tanti vantaggi in futuro per questo motore..

[Fradetti]

Ieri in autostrada ho visto 3 Lotus Elise in fila che entravano in un Autogrill.... che spettacolo

[Quincy_it]

Originariamente inviato da 85kimeruccio

da quel che ho capito questo sembrerebbe un sistema di attuazione delle valvole senza albero a camme.

niente male!! vedo tanti vantaggi in futuro per questo motore..

Sembra molto interessante!

[JENA PLISSKEN]

ottimo...dalla Lotus esce solo roba di un certo livello...peccato x la linea della Europa S...un obbrobrio

[checo]

Originariamente inviato da Fradetti

Ieri in autostrada ho visto 3 Lotus Elise in fila che entravano in un Autogrill.... che spettacolo

erano quelle di porny?

[Coyote74]

Un sistema simile, per rivoluzionario che sia, ha delle problematiche intrinseche da far paura. Tenendo conto di questo, non vedo perchè abbandonare la cara, vecchua e buona strada dell'albero per soluzioni esotiche che lasciano il tempo che trovano

[Engelbert]

Originariamente inviato da Coyote74

Un sistema simile, per rivoluzionario che sia, ha delle problematiche intrinseche da far paura. Tenendo conto di questo, non vedo perchè abbandonare la cara, vecchua e buona strada dell'albero per soluzioni esotiche che lasciano il tempo che trovano

Beh magari questa soluzione non verrà mai adottata, ma un po' di sperimentazione non fa certo male in ambito motoristico.

x Kimeruccio:
COme mai non hai ancora aperto un thread sulla prodrive p2??

[Fradetti]

Originariamente inviato da checo

erano quelle di porny?

non lo so... ma se lo fossero state mi sarei fermato pure io

[85kimeruccio]

Originariamente inviato da Engelbert

Beh magari questa soluzione non verrà mai adottata, ma un po' di sperimentazione non fa certo male in ambito motoristico.

x Kimeruccio:
COme mai non hai ancora aperto un thread sulla prodrive p2??

beh... sperimentazione boh.. kissà.. qualcosa di nuovo devono tirare fuori anche gli altri.. nonpenso si vivrà solo a uniair


la p2? bah... non volevo scocciare

[Swisström]

Originariamente inviato da Fradetti

non lo so... ma se lo fossero state mi sarei fermato pure io

sei dell'altra sponda?

[Gos]

se non sbaglio la fiat sta facendo la stessa cosa con l'uniair......i primi motori dovrebbero uscire nel 2007

[85kimeruccio]

Uniair è un "aiuto" dell'albero a camme che varia il movimento delle valvole con un sistema idraulico. tanto per farla spiccia

cmq penso sarà il futuro stà roba... non so ma, ci vedo perfino un futuro step degli uniair.

[ninja750]

bmw con il valvetronic ci ha già pensato (inutilmente) tre anni fa

[Zappz]

interessante, sicuramente avra' molti vantaggi sulla gestione elettronica della distrubuzione (gia' ci vedo del tuning estremo ), ma finche' nn sara' perfezionato per bene avrei paura a comprare qualcosa del genere per questioni di affidabilita'...

[Fradetti]

Originariamente inviato da Swisström

sei dell'altra sponda?

no.... è che non mi dispiacerebbe prenderlo a schiaffi