Here's what FIAT is giving America, the most efficient least polluting gasoline engines ever

[divideandconquer]

MARCH 08, 2009
Fiats Multi-Air Engine Breakthrough for 25% more Fuel Efficiency and Less Pollution


MultiAir turbocharged and downsized engines can achieve up to 25 per cent fuel economy improvement over conventional naturally aspirated engines with the same level of performance. Maximum power is increased by up to 10 per cent thanks to the adoption ofa power-orientated mechanical camshaft profile. Low RPM torque is improved by up to 15 per cent through early intake valve closing strategies that maximise the air mass trapped in the cylinders. Elimination of pumping losses brings a 10 per cent reduction in fuel consumption and CO2 emissions, both in naturally aspirated and turbocharged engines with the same displacement. Optimum valve control strategies during engine warm-up and internal exhaust gas recirculation, realised by reopening the intake valves during the exhaust stroke, result in emissions reductions ranging from 40 per cent for unburnt hydrocarbons and carbon monoxide (HC/CO), and up to a 60 per cent cut in oxides of nitrogen, (NOx). Constant upstream air pressure, atmospheric for naturally aspirated and higher for turbocharged engines, together with extremely fast air mass control, cylinder-by-cylinder and stroke-by-stroke, result in a superior dynamic engine response, and enhanced driving pleasure. MultiAir is applicable to all internal combustion engines, regardless of the fuel used. It can be adapted for diesel engines to reduce their NOx emissions and make particulate filters significantly more effective.

In short, an engine equipped with Fiat MultiAir technology is more powerful, more responsive across the entire engine speed range, uses considerably less fuel, and reduces all types of exhaust emissions by a substantial amount. It will also assist in enabling Fiat to maintain its lead in low emissions and low fuel consumption technology, which has seen Fiat crowned for the past two years as the number one car maker for the lowest range-wide CO2 emissions.
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<http://nextbigfuture.com/2009/03/fiats-multi-air-engine-breakthrough-for.html>

These extraordinary environmentally positive engines will be built in the millions right here in America in a few years.

[NYC_SKP]

1. Sweet! Seems to use valves to control fuel/air delivery more than traditional throttle valves..

Here's their page:

http://www.alfaromeo.com/

Alfa MiTo:

[tridim]

2. As a certified Fiat nut I love this news.

Unfortunately I'm Fiat-less for the first time in my life and that hurts.

[sailor65]

3. We already have this

all Fiat brought us is new semantics. This is another flavor for Variable Valve Timing. Great process, but not new and certainly not brought by Fiat.

The GM Family 0 engines coming online this year do very similar things, and Fiat had nothing to do with those.

[Fumesucker]

5. I built a 400 small block Chevy in 1980 that had variable valve timing.

You're right, it's not a new technology..

http://www.rhoadslifters.com/

Over 100,000 satisfied customers, including big name engine builders like Gale Banks, will tell you...With Rhoads lifters you can run more cam and still have great low-end torque, engine vacuum and idle quality. The secret? Variable Valve Timing! Rhoads' exclusive patented design reduces lift and duration on the low-end and restores it on the top.

[divideandconquer]

7. FIAT had the first patents on variable valve timing in 60's

"Fiat was the first auto manufacturer to patent a functional automotive variable valve timing system which included variable lift. Developed by Giovanni Torazza in the late 1960s, the system used hydraulic pressure to vary the fulcrum of the cam followers (US Patent 3,641,988). The hydraulic pressure changed according to engine speed and intake pressure. The typical opening variation was 37%.
In September 1975, General Motors (GM) patented a system intended to vary valve lift. GM was interested in throttling the intake valves in order to reduce emissions. This was done by minimizing the amount of lift at low load to keep the intake velocity higher, thereby atomizing the intake charge. GM encountered problems running at very low lift, and abandoned the project.
Alfa Romeo was the first manufacturer to use a variable valve timing system in production cars (US Patent 4,231,330). The 1980 Alfa Romeo Spider 2.0 L had a mechanical VVT system in SPICA fuel injected cars sold in the United States. Later this was also used in the 1983 Alfetta 2.0 Quadrifoglio Oro models as well as other cars. The system was engineered by Ing Giampaolo Garcea in the 1970s.<2>"

<http://en.wikipedia.org/wiki/Variable_valve_timing>

[sailor65]

9. And they were ingenious....

considering a good backyard mechanic could do the upgrade.

[Fumesucker]

4. I took this from their website..

Looks like it uses oil pressure controlled by solenoids to vary the valve timing according to engine demand.

[divideandconquer]

6. Yes, it goes beyond variable valve timing and GM doesn't have it

How does Fiat's MultiAir vary from existing variable valve timing (VVT) systems?

Current VVT systems rely on mechanical systems to open and close the valves. Engineers have long understood the benefits of changing valve opening and closing times to tweak an engine's power and emissions performance, depending on the need for power or parsimony.

Valves are an engine's nose and mouth – it inhales through inlet valves and exhales through exhaust valves. Sounds simple enough, but actually engines are a lot like people. Depending on what they're doing, they need to breathe more or less air and the timing and rate of their breathing needs to vary. Like competitive swimmers who time their breathing to match the stroke, an engine wants to take long deep breaths when it's working hard, and short shallow ones when it isn't.

Trouble is, it can't. The ancient method of opening and closing valve, the camshaft, is still in use today because it's simple to make, robust and very effective. Each valve is opened by a rotating cam on the camshaft whose shape and size controls how the valve opens and shuts and when it does so. The valve is closed by a simple spring because, in 100 years, no-one's found a better tool for the job. But what's right for developing high power at high rpm isn't right for that torquey, low-speed slog around town and greater variability of valve opening and closing helps reduce consumption and CO2 emissions too.

How do other variable valve timing systems work?

A lot of modern engines try to overcome the inadequacies of the traditional valvetrain with phasers to vary the timing of when valves open and shut. They may also have cam profile switching (like the Honda VTEC system), which switches to a hotter cam profile at higher revs. But the effect is limited. If the engine were a swimmer, it would still be gagging to get the right amount of air at exactly the right time, like when its face was under water.

The MultiAir system replaces the twin camshafts of a four-valves-per-cylinder engine. It's so cleverly designed, not only can it be incorporated in new engines, it fits exsiting motors too – so potentially all sorts of engines (not just Fiat's) could use it. The single camshaft opens up all four valves. Exhaust valves are not variable and are opened in the usual way by mechanical cam lobes. But between the inlet cam lobes and inlet valves are hydraulic chambers from which oil can be released by electronic solenoid valves.

How MultiAir works

When the electronic solenoid valve is closed, the chamber becomes a solid body and the valve follows the profile of the cam exactly. But if the electronic solenoid is opened to release some of the oil, the chamber shrinks to absorb the cam movement and the valve opens less. Choosing when to bleed the oil from the chamber, as well as by how much, makes it possible to control timing and lift as well as the duration of opening on an individual, valve-by-valve basis.

The mechanical inlet cam profile is 'hot', that is to say designed for high power at high rpm. For maximum power, the chambers remain full so the valves are opened to their maximum for longer. At slow speed, the solenoid is opened near the end of the cam's 'ramp' to close the valve early, maximising the amount of air trapped in the cylinder and improving torque. At part throttle, different strategies are used, partially opening the valves to trap just the right amount of air and speed up air flow.

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<http://www.carmagazine.co.uk/News/Search-Results/Industry-News/Tomorrows-world-Fiats-MultiAir-engine-tech/>

[sailor65]

8. Ok, I'll bite...

but before we continue this discussion, do you actually understand the technologies, or are you just searching, copying and pasting?

If it's the latter, you're not going to understand the new GM engines.

On edit: I should probably note also that we're in the process of building all of the equipment that is going to build these engines for Flint Engine South. Which means I have every single part of the new Fam 0 engines right here in my building.

[divideandconquer]

10. So how does GM's engine achieve the same result?

BTW, GM buys FIAT diesels for their European cars.