MultiAir at work: This photo shows the position of red solenoids that push oil into actuators to open and close air-intake valves.
Credit: Chrysler
Energy
Going Further on the Same Tank
A technology coming to Chrysler vehicles can improve the fuel economy of standard gasoline engines by 25 percent.
- Thursday, August 19, 2010
- By Julie Halpert
Chrysler is unveiling a way to squeeze more fuel efficiency out of existing gasoline engines, adopting a technology pioneered by Fiat, which controls Chrysler. The effort represents the latest strategy by automakers to meet federal standards that require an automotive fleet to get an average of 35.5 miles per gallon by 2016.
While General Motors and Ford have made progress in retooling their gasoline engines to make them more fuel-efficient, Chrysler has lagged. Now Chrysler hopes to catch up with the MultiAir technology, which it claims will increase fuel economy by 25 percent.
In a conventional engine, a camshaft opens and closes the valves that bring air into the engine. These valves all make the same movement all the time, even at low engine speeds, when less air is required. The MultiAir system is different because it electronically determines the most efficient way to open and close the valves, depending on road conditions and necessary power, allowing the car to run more efficiently at all speeds.
Here's how it works: A small solenoid, a mechanical device that can act like a switch, opens and closes the valves. This solenoid adjusts the cycle of valves opening and closing so that the engine takes in the best amount of air for the load it's handling at any given moment. Opening the valves for a short period of time at low loads is less work for the engine, increasing its efficiency. And because the system can open the valves longer when more power is needed, it can extract more energy out of the engine.
As a result, MultiAir not only increases fuel economy, it also increases the engine's torque by 15 percent, says Chrysler spokesman Nick Cappa.
"It gives the engine a more efficient breathing pattern whether at idle or 6,000 rpm," Cappa says.
The MultiAir technology was launched by Fiat in Europe in 2009. Its first application in the U.S. will be on the 2011 Fiat 500. Cappa says Chrysler is looking to use MultiAir on its new, more efficient Pentastar six-cylinder engines, which are used in everything from pickup trucks to small sedans. Cappa says the cost of adding the technology to a car hasn't been determined yet.
Chrysler's use of the technology is the latest attempt to improve the fuel efficiency of internal combustion engines. Shifting to radically different engines, like those in electric cars, may offer the best long-term benefits for the environment and fuel economy. But the infrastructure necessary for vehicle charging stations won't spring up overnight.
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gophermobile
1 Comment
- 536 Days Ago
- 08/19/2010
Isn't this similar to VTEC on Honda cars and what already exists on other manufacturers (I forget what other companies call it)? If so...talk about being behind the times!
lasertekk
146 Comments
- 536 Days Ago
- 08/19/2010
No, not even close. The old vtec technology is almost a full two generations behind this engine management hardware. Vtec came out in the 90's. This is much more recent. Reading the technical editorials of various car magazines and websites, they all agree (how rare) multiair represents a major revolution for the ICE.
colinnwn
88 Comments
- 536 Days Ago
- 08/19/2010
Re: It is called variable valve timing
And almost all implementations I know of provide one or 2 extra maps of how the valvetrain can move in relation to the cylinder positions. It does this by releasing hydraulic pressure on the lifters or by shifting the position of the camshaft drive. This improves efficiency and torque somewhat, but in making it cheap and reliable, it doesn't provide the maximum benefit.
With full electonically actuated valvetrain, you can map the valve movements to the cylinder precisely based on engine load to get the best possible efficiency and power from this technology. In the past the electrical power demands and actuator sizes that could withstand engine heat were problematic. Chrysler has apparently resolved this.
dasigi
1 Comment
- 532 Days Ago
- 08/23/2010
Re: It is called variable valve timing
Does the new MultiAir engine eliminate the camshaft altogether by replacing it with solenoids and electronics?
colinnwn
88 Comments
- 531 Days Ago
- 08/24/2010
Re: It is called variable valve timing
Yes.
It also means you can get rid of the starter motor if you have a small fan to purge some fresh air into the cylinders.
zelectron
7 Comments
- 536 Days Ago
- 08/19/2010
to 40% pearhaps 50% asa... total until 450% ?
Carnot's cycle demonstrate the absolute limit to 50%
jrkennedy2
1 Comment
- 536 Days Ago
- 08/19/2010
Could this not be combined with the fuel injector technology reviewed earlier in TR? Seems like a nice pairing.
joewilder
4 Comments
- 534 Days Ago
- 08/21/2010
Or could this technology work on a 2 cycle engine? I really like the simplicity of Lotus's Omnivore engine, with it's fewer parts and combined head and cylinder structure. They have been having trouble making it idle. Perhaps this is something further they can look at.
stuber@mit.edu
1 Comment
- 530 Days Ago
- 08/25/2010
This technology is about replacing the mechanical valvetrain with electronically controlled valvetrain. Two-strokes don't have valves at all.
zaczek@prodigy.net
3 Comments
- 536 Days Ago
- 08/19/2010
Could you explain the valve tech
My son put a turbo charger on a 1995 Camaro,,, yes old technology. But now he has to reprogram his cars new computer to recognise this new hardware. This winter he most likely will purchase a program that will "optomize" the performance of the car based on how he drives. This latest system looks like another "Retro Fit" that he could do to an existing engine to give him better performance (torque) and much better efficiency (MPG).
Please remember any really new technology will still need the egg head / motor monkeys to keep them on the road after the warranty is over. He now smiles when I say it's power to weight ratio today not just raw power. When his brother and sister engineers are around I say the Camero is the "Prof of Conecpt" car.
We don't want Technology Review to become the Popular Mechanics of MIT but we would like to see more working machines and less announcements of lab results and company PR.
14159265358979323846264338327
1 Comment
fensterbaby
7 Comments
- 535 Days Ago
- 08/20/2010
Farther versus Further
Throughout history, farther and further have been used interchangeably. Even the Merriam-Webster Dictionary states that the words are interchangeable; they are the inflected form of far. It is not until recent history that they are becoming distinguished by grammarians.
corleyman
1 Comment
- 532 Days Ago
- 08/23/2010
Of course to open the valves for shorter and longer intervals, the amount of fuel injected and air allowed in (pressure) would need to be varied as well.
I'm no high-tech mechanic, but why hasn't anyone proposed using an "air injector" just like how fuel injectors work? Is it just that air is in the gaseous state while fuel is in the liquid state, thus allowing for more precise controls for fuel but not air?
Is anyone experimenting with coupling air injectors and fuel injectors? If so, I could imagine even further down the line not even needing valves ... if the injectors could hardened enough.
paulfmeyer
18 Comments
- 531 Days Ago
- 08/24/2010
The Scuderi Air-cycle engine is indeed using an air-injection approach.
http://www.scuderigroup.com/
colinnwn
88 Comments
- 531 Days Ago
- 08/24/2010
The Scuderi is a good example of what you are talking about.
But the simpler version of your proposal is already being done. Valves are simply large low pressure air injectors that normally use atmospheric pressure to get the air into the cylinder. That keeps their efficiency high versus trying to inject a lot of air through a small orifice at high pressure, which is very inefficient.
The simple version of your proposal is a turbocharger or supercharger that pressurizes incoming air. Then with electronically controlled wastegate valve and cylinder valves, you can specifically control the amount of air allowed into the cylinders.
pattakoncom
4 Comments
- 504 Days Ago
- 09/20/2010
Quote from the internet:
"The Fiat 500 TwinAir (the two cylinder version of MultiAir) is equipped with a two-cylinder turbo 85 HP (900 cc) engine which has the lowest CO2 emission levels for a petrol engine (up to 95 g/km) without compromising performance and driving pleasure."
Fiat with Schaeffler-INA made a good step ahead among all the carmakers, because no other VVA system (neither the valvetronic of BMW, nor the VVEL of Nissan, nor the ValveMatic of Toyota, nor the electromagnetic VVA of Lotus or of Valeo or of Siemens …) can achieve what the MultiAit / TwinAir / UniAir do.
Yet the MultiAir / TwinAir / UniAir system of Fiat can be further improved.
Take a look at the PatAir and the PattAir Electro-Hydraulic systems, at http://www.pattakon.com/pattakonHydro.htm .
The PatAir uses the same hardware with the MultiAir (only the profile of the intake camlobes of the camshaft changes to have a duration of some 400 crank degrees).
The PatAir provides all the “modes” and strategies of the MultiAir system, which is based on the “Ingoing Air Control”, plus the “Outgoing Air Control” modes and strategies that are more efficient, especially at urban cycle, i.e. at medium-low revs and partial load operation.
In the “Ingoing Air Control” the sooner the intake valve closes, the more "ingoing air" is kept from entering the cylinder during the suction; the later the intake valve closes, the heavier the load.
In the "Outgoing Air Control" cycle, the later the intake valve closes, the more "outgoing" air is left to escape from the cylinder back to the intake manifold as the piston moves towards TDC at the compression stroke; the engine of Toyota Prius (Atkinson/Miller cycle, over-expansion) operates in a limited "Outgoing Air Control" cycle.
The PattAir runs according the “Outgoing Air Control”.
Its difference from the MultiAir and the PatAir systems is that the intake valves open pure mechanically (the valve acceleration and jerk can be as high as in the mechanical systems); the hydraulic system gets into play only during the closing of the intake valves in order to control the quantity of air / mixture trapped into the cylinder.
In Ferrari (of Fiat) they decided not to use the Fiat-MultiAir system because it doesn’t fit to the character of their cars.
With the PattAir system, a super-car can keep its sport character, while reducing a few times its emissions and consumption at the combined cycle.
Manousos Pattakos
RBynum
1 Comment
- 481 Days Ago
- 10/13/2010
Remember the old days when you only had a carburetor and butterfly valves and a screw driver to adjust the fuel/air mix?
pattakoncom
4 Comments
- 478 Days Ago
- 10/16/2010
I like carburetors too: simple is nice.
Take a look at at http://www.pattakon.com/pattakonRod.htm ; there is a carburetor there; it can run on pure ethanol even in winter days ; when it runs on gasoline, few cars accelerate, at the traffic lights like this 20 years old carburetor (flat torque from 1000 to 7000 rpm)
The Desmodromic Variable Valve Actuation (or DVVA) seems having unlimited revving capacity (i.e. it can rev higher than F1 and MotoGP pneumatic valves, or Ducati MotoGP Desmo). Take a look at http://www.pattakon.com/pattakonDesmo.htm
Unfortunately, when it comes to the new regulations, to compromise with the digital control is unavoidable.
Fiat and Schaeffler-INA with their MultiAir / UniAir / TwinAir system turn the internal combustion engine into a digital device.
The fact that the Fiat 500 TwinAir is currently, according the official tests, the greenest gasoline engine car is indicative, if not proof, that there is no control like the digital control.
Schaeffler-INA has all it takes to make a DVVA running at 20,000 rpm and still comply with even stricter regulations, as it did with the Fiat MultiAir/TwinAir: the digital control is hardly different.
Manousos Pattakos
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jschwieg
1 Comment
Re: Duh?
Crazy thought, improve the quality of our vehicles and more people may buy them. While capitalism should make companies compete to make better and better products, the auto industry instead has sucked every last ounce of quality out of their products to maximize profits. The problem with this strategy is that sooner or later someone comes along with a higher quality product (read Japanese automakers circa 1980 and 2001) and beats the pants of you.
Suddenly with higher standards US automakers are adopting off the shelf technology to improve efficiency when they should have been doing this all along.
Come on folks, step up and gives us the stuff!
Reply
thegreenmarket
1 Comment
Re: Duh?
To say that Chrysler`s efforts are too little too late would be an understatement. Given the competitive environment in the auto industry, Chrystler`s new technology is hardly revolutionary.
Nissan already has the mass produced Leaf
http://thegreenmarket.blogspot.com/2009/10/nissans-greener-cars.html
Toyota and Tesla have teamed up to create a fully electric sedan for mass production
http://thegreenmarket.blogspot.com/2010/08/toyota-and-tesla-making-electric-sedan.html
There is already a fully electric 4x4
http://thegreenmarket.blogspot.com/2010/08/e-range-first-fully-electric-4x4.html
Hyundai is already getting over 30 mpg
http://thegreenmarket.blogspot.com/2010/08/hyundais-fuel-efficiency-leadership-and.html
At at 40 mpg, the Jaguar XJ gets better fuel economy than Chrysler`s goal of 35 mpg
http://thegreenmarket.blogspot.com/2010/08/jaguar-xj-greener-luxury-car.html
Honda`s hydrogen powered FCX Clarity FCEV gets 240 miles on hydrogen created by sunlight
http://thegreenmarket.blogspot.com/2010/08/hondas-fcx-clarity-fcev.html
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