Maybe we can use these. Apparently they are much faster so the dynamic
range is higher.

http://www.conti-online.com/generator/www/de/en/cas/cas/functions/contact/contact_en.html

http://www.autoweek.com/apps/pbcs.dll/article?AID=/20060609/FREE/60605013/1024/LatestNews

"Piezo injectors are just now coming to Europe on high-end vehicles from Range
Rover, Audi and Mercedes-Benz. Piezo is widely seen as the next big evolution of
the diesel engine.

Small crystalline discs in the injector change shape when electricity is
applied. When the discs change shape, diesel fuel under high pressure is shot
through a needle in a fine spray into the engine's combustion chambers.

As many as seven injections can be made in a single piston stroke, compared with
one or three injections in most diesel engines. Those multiple injections lower
the temperature in the combustion chamber, which in turn lowers oxides of
nitrogen emissions.

Piezo injectors also reduce noise, vibration and smoke, all unpopular traits of
a diesel engine."

"The piezo injectors to be used in the Super Duty pickups will be made by a
joint-venture company in Blythewood, S.C., owned by German supplier Siemens VDO
and International. Production of the injectors is scheduled to start in
December,[2007?] said Siemens spokesman Brad Warner. He would not confirm any
vehicle applications but said the plant's entire output will go to International."

Continental Teves, Inc.
One Continental Drive,
Auburn Hills, MI 48326, USA
Phone: +1 248 393-5300
Fax: +1 248 393-5301


----------------------------------------------------------------------------------

Sorry about the size of that picture folks. I sent it without checking it.

Here is some more info on these injectors.

For all I know the RX8 engine injectors are already Piezo and not solonoid.
They do seem to click down to a very narrow pulse of around 1 ms.
I'll explore this more with pulses less than 1 ms.

I'll know more when I get this engine on the dyno with the RX8 injectors.

Paul Lamar

http://www.thehindubusinessline.com/2004/03/15/stories/2004031500150900.htm

Many companies are working on the piezo fuel-injector technology. At the Frankfurt show, Delphi unveiled the highly advanced piezo-based injector intended to meet stringent emission standards of US07 and Euro 5 for heavy vehicles.

BESIDES improvements in combustion and exhaust gas after-treatment, high pressure multiple fuel injection in precisely metered dosages and in correct spray shape is the primary focus of diesel engine manufacturers for the development of cleaner, quieter and fuel-efficient diesel engines.

In the common rail system, the fuel is pressurised by a supply pump and stored in a closed reservoir or rail, ensuring that an injection pressure up to 1600 bar (160 Mpa) is available at all times and, even at low engine speeds. And the fuel is then injected into the combustion chambers by solenoid injectors.

The fuel pressure is controlled by the supply pump's electromagnetic valve and kept constant at the preset value. The total volume of the fuel can be injected in multiple steps — fixed pilot injections, main injection and the post injections.

Leading companies such as Denso and Delphi, pioneers in introducing controlled engine management system allowing programmable injection events, including timing and pressure, have demonstrated the success of this system on European market cars.

Delphi's next generation common rail system (Multec) using five-injections in steps at 1800 bar [24,000 psi], uses a solenoid injector to optimise the fuel rate, spray shape and accuracy. According to the recent reports in SAE literature, the Multec system is used by Renault/Nissan, PSA Peugeot Citroen, Hyundai/Kia, Ssang Yong, and Ford's Premier Auto group.

Although a high level of innovation has taken place in solenoid injection technology, the Piezoelectric effect, a well known phenomena in science, which lay dormant without practical application for a long time, has suddenly matured into hard-core technology after 1920.

It has recently found several commercial applications. The significant application is in diesel technology for the development of a quieter and clean burning diesel engine. Piezo injection is gradually replacing the solenoid injection.

Piezoelectricity, a Greek-derived word meaning "pressure electricity", was discovered in 1880 by the brothers Pierre and Jacques Curie.

They found that certain non-conducting asymmetrical crystals generated a potential difference across the opposite faces as a result of application of mechanical stress between these faces. The electric polarisation produced is proportional to the stress, and the direction of the polarisation reverses if the stress changes from compression to tension.

This effect is also reversible. If the opposite faces of the crystal are subjected to a potential difference, the crystal lattice changes within a few milliseconds resulting in expansion or contraction giving a change of shape, thus producing enormous force for actuating a valve by physical contact and elastic coupling. Solenoid is a magnetic technology and is based on a force that arises at a distance. Piezo actuators can be designed to replace any solenoid but they always come out bulkier. On the other hand, they take much less power to operate. With the discovery of new piezoelectric ceramics, the designers can actually tailor the material for a definite purpose. Siemens VDO Automotive was the first to develop a common rail injection using Piezo electronic actuators, the greatest advantage of which is the speed compared to solenoid valves. Multiple injections are designed to produce clean and efficient combustion without a steep pressure rise, which results in quieter operation.

According to recent SAE literature, many companies are working on the piezo fuel-injector technology. At Frankfurt show, Delphi unveiled the highly advanced piezo-based injector intended to meet stringent emission standards of US07 and Euro 5 for heavy vehicles.

The company expects a new injection system (Piezotec) to generate about a 25-30 per cent reduction in emissions compared to current production piezo common rail technology. Siemens has had piezo common rail injection systems in production vehicles for several years, starting from the Peugeot 307.

Now the company is starting work on a smaller piezo actuator integrated directly into the valve shaft, enabling the pressure in the system to be increased to 1800 bar instead of 1600 bar [24,000 psi]. According to Siemens, pressures up to 2000 bar [30,000 psi] are possible in their system.

Bosch, in their Bamberg plant, have replaced the unit's magnetic actuator by a package of several hundred piezo crystals for the actuator, which switches very fast, requiring only half the time attained by a magnetic switch. [Ah So]

Although it may be an interesting laboratory curiosity, the extension of this work has a tremendous impact in curing the ills of a two-stroke engine, where fuel can be injected either in the manifold or into the cylinder without short-circuiting part of the fuel through the exhaust.

This suggestion was made in the mid-1980s by Prof R. K. Pefley of Santa Clara University in the course of an early NSF funded project in collaboration with IIT Madras.