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Chrysler Group LLC Introducing Fiat’s 1.4-liter FIRE with Multiair to Powertrain Lineup, Investing $179M to Launch Production

Fiat’s Multiair system on the 1.4-liter FIRE. Click to enlarge.

Chrysler Group LLC will begin production in the fourth quarter of 2010 of Fiat’s 1.4-liter, in-line four-cylinder Fully Integrated Robotized Engine (FIRE) featuring Multiair for incorporation into its powertrain lineup. (Earlier post.) The first application of the engine will be in the North American-built Fiat 500 that will go into production in 2011.

The engine, well-suited for a small car application, delivers 100 hp (75 kW) at 6,750 rpm and 95 lb-ft (129 N•m) of torque at 4,250 rpm. A turbo version also will be available in future applications. The 1.4-liter FIRE features Fiat’s Multiair technology which significantly reduces emissions, while improving fuel economy and power delivery. (Earlier post.)

1.4-liter, Four-cylinder Turbo FIRE with Multiair. Click to enlarge.

Chrysler Group LLC will invest $179 million to produce the engine at the company’s Global Engine Manufacturing Alliance (GEMA) plant in Michigan. The investment will create up to 573 new jobs industry-wide, including up to 155 new Chrysler Group jobs.

The 1.4-liter FIRE features four valves per cylinder and incorporates Fully Variable Valve Actuation (FVVA), also known as MultiAir. Multiair delivers an increase in power up to 10% and a reduction in fuel consumption and emissions up to 10% when compared to similar engines. A turbo version of the engine also is planned and will produce a fuel economy improvement up to 25% when compared to a V-6 engine with equivalent power.

The MultiAir system consists of electro-hydraulic variable valve actuators filled with conventional oil, which is interposed between the camshaft and each valve. A solenoid valve is energized every 360 degree camshaft rotation, regulating the quantity of oil addressed to the actuator or to a reservoir. The lift of the valve is a function of the quantity of oil addressed to the actuator, ranging from full lift to complete valve closure. Each solenoid valve may also delay application of the actuator in advance, leading to late valve opening or early valve closing.

The 1.4-liter FIRE with Multiair is the first mass production engine to incorporate such technology to control the intake valves. Dedicated components have been developed to accommodate four “bricks” (one for each cylinder) which package relevant components. MultiAir technology can be adapted to different types of engines (including Diesels for enhanced NOx control) and is planned for Chrysler Powertrain's 4-cylinder World Gas Engine and all-new Pentastar V-6.

MultiAir is exclusive for Chrysler Group in North America and is based on a series of Fiat Powertrain patents related to hardware, combustion strategies and controls which allows for full control of the lift and timing of engine valves.

(In the early 1970s, robotics in assembly plants was not common. The term “FIRE” came into existence when Fiat integrated the use of robotics in the production process of manufacturing plants. Although mechanized assembly is commonplace today, the brand name FIRE has remained with Fiat’s powertrain line up.)



FIAT may wish they could FIRE after dealing with the UAW!


More moving parts = higher chance of something breaking...I don't like it.

Henry Gibson

High torque air hybrids should replace this engine immediately. In the future only diesel engines with great exhaust gas treatment should be built and these as a hydraulic hybrid. Turbine hybrids that run on diesel are also good enough. ..HG..



There are loads of MultiAir engines running already and there aren't any quality problems related specifically to that technology.
Cars are becoming more complex every year but they still break down increasingly less, so I think you can "like it" even though I have to bow down to the inherent logic of "More moving parts = higher chance of something breaking"

Stan Peterson

Fiat's "Multiair" variable Valve Lift technology transforms the ICE engine. In conjunction with VVT it allows easy use of alternative combustion cycles such as the Atkinson, normal aspirated, and Miller, supercharged cycles, as well as the foundation stone of the Otto cycle.

It even offers the method to implement Homogeneous Charge Compression Ignition, HCCI on such ICE engines.

It allows the engine combustion engineer to do away with the throttle and its losses. These losses result in the lower mileage of ICE gasoline engine when compared to the Diesel cycle mileage.

In plain words it allows a significantly lighter gasoline engine to produce the same mileage as a diesel, but without the diesel disadvantages. ICE engines have advanced to the point that they are now routinely delivered as ZERO Pollution engines, recording sub T2B2 levels of emissions, and matching pure electric, and sometimes bettering fuel cell cars.

Meanwhile the cleanest diesels available, those meeting the present US standard of T2B5, struggle to be able to achieve a level 1000 times dirtier. European so-called "clean diesels" a genuine contradiction in terms, are about 9000 times dirtier.

CARB listed some 56 car models for sale from virtually all the car makers, in the 2008 model year, the last available data, that met the ZERO pollution level. Of interest, the cars from Chrysler with the World Gas Engine, currently built at Dundee, that are soon to receive this technology too, are cars that already achieve the CARB ZERO pollution rating.

This is a significant spread of technological advance in conventional ICE technology. A Dodge Caliber auto presently achieving 24 city 30 highway mpg could be improved to 29 city-35 highway mpg with its World engine, with no other change, while reducing 0-60 by 1.5 seconds. Replacing with a FIRE engine the mileage could rise to 37-45 mpg.

Bradford Wade

"It allows the engine combustion engineer to do away with the throttle and its losses."

Interesting. For those of us who are not engine combustion engineers, could someone explain how throttling an engine using a throttle plate creates losses, but throttling using the valvetrain does not?

The only way I can picture that being true would be if engine output is "throttled" by completely shutting down individual cylinders. Or does this technology somehow allow extremely lean combustion? If not, I don't understand why it would matter how the air flow into the cylinder is being restricted.


This might help

Chrysler should look at the 2 cylinder turbo 900cc multiair engine fiat is using in the 500. Pair that with a similar sized electric motor and that would be a pretty cool power train.

Bradford Wade

Ok. In the youtube video, they claim that optimizing valve timing reduces throttle losses. Reducing is a lot different than eliminating. I bet most of the throttle loss is still there.


Variable valve lift does significantly reduce the pumping losses as compared to using a throttled engine. This is one of the primary reasons diesel engines have an inherent advantage in efficiency - they do not use a throttle either. They control engine speed by the amount of fuel injected.

Anyway, back to the variable valve lift. Using conventional valvetrains, when the piston is in it's intake stroke and sucking air through the intake valves, the amount of air let into the cylinder is controlled by restricting the air via the throttle plate. So, the engine is "fighting" this added resistance during the entire intake stroke, which causes the "pumping losses" that are always mentioned. The lighter the load, the more the losses are.

With variable valve lift, the amount of air let into the cylinder is controlled by the duration the intake valves are left open. During that time, there is no throttle to add additional resistance to the air intake. I'm sure you might ask, what happens when the valve closes and the cylinder is still in it's intake stroke? Yes, that would cause a temporary vacuum, but this vacuum that is created on the intake stroke is going to help the engine during the compression stroke, since the cylinder will be going the other direction very shortly. This is the same premise that enables the various "cylinder deactivation" strategies that are employed. They simply close all valves in that case that and the vacuums essentially offset each other, and the deactivated pistons work more like springs.

Not sure if this helps...


Great question Bradford,

My take on it is that it wil allow full throttles operation at one end of its range and any combination (that includes throttling) that the CPU deems appropriate.
Since it would only throttle in favourable circumstances there should be no penalty.

This could also supply 'exhaust braking in non regen applications if the CPU so commanded.

I'd hate to be the 'robot' deciding which parts to replace in on rebuild.
there's a 'UAW'(type) saying that goes " If Jumbo's jet engines were designed to be worked on by monkeys, and they could, we would be in real trouble!


I'm not sure if Stan's post refers to the mechanical and manufacturing expense penalty or a fuel - combustion penalty but the first is not overcome by this high spec design (although this specific application makes no reference to DI.) DI versions can have compresion ratios similar to diesel in a low (sub 3,000) rpm 'donk'
The proliferation close tolerance components can't be simpler or less specified than diesel.

Emissions? there are many options albeit they may be best achieved through diesel gas offerings.


Throttling losses are not the only reason SI (gas) engines are less efficient than Diesels. Compression ratio is another.

If/when the Multiair engines incorporates both HCCI AND Fully Variable Valve Actuation maybe it will be able to match a Diesel.

I like the innovation, but am not so sure (but hope) this technology, from Fiat, will be a good buy.


The CO2-emissions of the Fiat Punto Evo with its 135 HP Mulitair engine is 129 g_CO2 per km.

The CO2-emissions of the Fiat Punto Evo with its 120 HP Diesel engine is 119 g_CO2 per km.

The difference between the diesel and the more powerful gasoline option is only 9%.

Needless to say, that there's no efficient way to convert gasoline into diesel. As long as there are cars running on oil, some will always need to run on gasoline.


Because the Mulitair concept also delivers more torque and power for a given engine size (as the volumetric efficiency at high torque requirements is improved), a smaller displacement engine can be chosen to accomplish the same task.
An engine with less displacement has inherently lower pumping losses.

Btw, this is not a new concept. BMW has had similar concept for many years:
(BMW has an electromechanical system whereas Fiat has an electrohydraulic system.)

Bradford Wade

Thanks for explaining that the cylinder can be filled early in the stroke, then the valve can close to create a vacuum that stores/recovers pumping energy by acting as a spring.

I can finally picture it. Thanks for helping me along.

Does anyone have an idea what percentage of throttle loss can be avoided this way? I hope I'm not the only garden-variety car nut (non-engineer) who finds this stuff interesting.

Bradford Wade

Ok. I've been trying to visualize this vacuum spring effect in more detail. Sorry, but I still have questions.

I can only picture one way less energy would be used by using the valve train to throttle the engine. That's because I can only picture two important variables: 1) the quantity of air, and 2) the quality of the air in the cylinder.

If the fuel/air ratio is the same, doesn't a particular engine output level always use about the same amount of air? I'm assuming that's true, so the quantity (mass) of air (variable #1) would be the same regardless of the throttle technique. That leaves us with variable #2. Maybe using the valve train as a throttle somehow produces a higher vacuum at the beginning of the compression stroke even though the mass of air is the same? I suppose the air could be cooler or have less exhaust gas mixed in it. Otherwise, it seems that the amount of vacuum present at the beginning of the compression stroke would be based on the amount of air needed for the engine output level, not on whether the air was restricted by a throttle plate or by the valve train.

Maybe part of the problem is that we're talking about two different things. I'm sure that adjusting the valve timing and lift can reduce pumping losses, but those losses should be in a different category than throttle losses --- pumping losses vs. throttle losses. In other words, if the improvement could be reproduced using a cam that's optimized for a particular RPM and load on a conventionally throttled engine, then maybe we should call it a pumping loss, not a throttle loss.

Are there other important variables? No doubt I'm missing something. Unfortunately, I'm still having trouble picturing how we can eliminate anything but a small portion of the throttle losses by shifting the point of air restriction.

If we want to eliminate more of the throttle loss, maybe we need to look elsewhere, such as cylinder deactivation, leaning, or energy recovery through a intake turbine generator?

Thanks again for all the helpful feedback.


GM is using the 1.4l engine from the Cruze for the Volt, so they might use this one for a future range extended plug hybrid. Perhaps THAT car would have the modular battery packs that allows the owner to chose what they need.

Stan Peterson


Variable Valve lift, VVL, is a desirable technology that improves mileage and power. VVL in Fiat's terminology, aka Fiat's version, called 'Multiar', is an inexpensive and trouble free, electro-hydraulic way of implementing VVL. VVL is something that every engine designer would like to incorporate in his engines.

Mercedes Benz intended to retire all its V6 engines, and to distinguish them from more mundane Chrysler ones, to implement an electro-mechanical VVL on their own Pentastar V6s, that would bear its Mercedes name. Ironically, Chrysler gets the Pentastar, Mercedes-quality modern V6. But now, upgraded with Fiat's VVL, and Daimler gets nothing, and is wondering what to do next with its obsolescent V6 engines.

VVL allows you to keep the air pressure in the intake manifold, at atmospheric or very near it, since the throttle plate, the source of regulating engine power via flow restriction, 'vacuum' is eliminated. Each cylinder can be individually varied as to how much air is going to be needed and supplied by its own valve lift and duration, in the next stroke of that particular cylinder. The air drawn in through the VVL cylinder valves is at atmospheric rather than partial vacuum, so it is essentially, partially supercharged.

This improves efficiency of the OTTO cycle. Not as much as full Diesel operation, but a long ways to wards it, from standard OTTO cycle operation.

Adding GDI, or Gasoline Direct Injection, inside the cylinder rather than in the intake manifold as is now common, so-called Sequential multi-port fuel injection, controls the fuel even better for each particular cylinder, prevents fuel puddling in the intake manifold, and allows the fuel to cool the compressed air in the cylinder. This in turn, allows an effectively higher compression ratio, actually a leaner burn. Each improves thermal efficiency.

Stan Peterson


Both VVL and GDI together, along with a faster engine computer, a simple chip change, and a O2 sensor for each cylinder, enables control sufficient to operate in Homogeneous Charge Compression Ignition, HCCI mode. The synergistic effect is to approach diesel thermal efficiency, and mileage but with cheaper gasoline, ICE toxic emissions cleanliness, and much lower weight.

The weight can be lower by almost half. A Cummins 6.7 I-6 liter diesel, weighs 1100+ pounds, but without all the cleanup paraphernalia, to merely reach still dirty T2B5 levels of cleanliness. A comparable Chrysler 6.4 liter Hemi V8 gasoline ICE, weighs 600 pounds together with its close-coupled catalytic converter(s).

Despite the image of ICEs as pollution belching devices, that was formerly true, you can actually NOW breathe the tailpipe of ZERO Pollution ICEs. After making a few simple precautions, such as cooling it, and adding some oxygen to the oxygen depleted exhaust.

A modern PZEV ICE powered car, quite common now, actually produces a cleaner air, than the ambient air quality in the Los Angeles basin. I, as an engineer, never expected the ICE to get that clean. Neither did the CARB. They created the PZEV category for their preferred non-ICE power sources as a illustrative trick, with the expectation that ICEs would never reach this level; but they have done so.

In contrast, if you tried breathing of the tailpipe with a 'clean' T2B5 diesel exhaust, you'd soon be D-E-A-D. If you breathed an EU 'clean diesel' you'd be dead, but much quicker.


A way to look at Variable Valve Actuation (VVA) is to picture the intake valve closed early or left open late enough to “expel back” enough of the incoming air to reduce power.
Thus instead of throttling and creating a vacuum above the downward moving piston (when reduced power is required) you just let the engine breath easy but reject some of the intake air by early or late intake valve closing.
Early and late intake closing are about the same, both reduce the effective displacement (during the intake stroke).
Throttling and VVA both reduce effective compression ratio and power, but VVA does not require extra power (and fuel) to perform the work of pulling the air past the throttle.


so-called Sequential multi-port fuel injection, controls the fuel even better for each particular cylinder,

A Cummins 6.7 I-6 liter diesel, weighs 1100+ pounds, but without all the cleanup paraphernalia, to merely reach still dirty T2B5 levels of cleanliness. A comparable Chrysler 6.4 liter Hemi V8 gasoline ICE,

Except that Sequential DI is the correct term and the cummings motor is a heavy duty heavy flywheel ruggedised unit while the Chrysler is a light duty and high rpm unit so the two cannot be compared.
you should compare like with like.

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