Nice to finally see the Air Impulse Valve finally coming to market. Essentially, it replaces the conventional butterfly valve and regulates air intake by the cylinder by opening the manifold fully, but only for a fraction of each intake stroke. The intake air no longer flows around a partial obstruction. In theory, the system could be used in boosted engines, but the gains described above apply to naturally aspirated gasoline designs.

At low RPM, an LTV can be switched multiple times during an intake stroke. If these events are timed correctly, gas dynamic resonance in the intake manifold is improved. Maximum mass flow into the cylinder can be increased by 15-20% at all engine speeds. This enables significant downsizing and downspeeding of the engine, enabling additional fuel economy gains.

The actuation mechanism for the valve is not described in detail above or on Mahle's web site. Last I read a paper on the status of LDV development (>18 months ago), it was essentially a flap mounted on a flexible shaft anchored at the far end (= torsion spring). An anchor mounted on the same shaft but outside the air pipe allows magnets to hold the valve either open or closed - the neutral position is 50% open. During engine start, the flap is excited into oscillation and caught in the open position before the starter motor cranks the engine. Normal operation begins as soon as the cylinders are fired.

It is possible that Mahle has by now figured out cheaper but equally fast pneumatic or hydraulic actuation. Switching times of just 3ms are hard to achieve, though. For maximum benefit, you need a short distance between cylinder and LTV, i.e. one LTV per cylinder.

Rafael,
Fascinating. How mature is this technology? (When do you think such a system could see implemantation?)

Who is Mahle anyway? Are they a big company? Is it a European equivalent to Delphi?

Bottom line, is this near term or is this a small company's pipe dream?

just try to think how many VW and Porsche engines were built since the 1940's and you'll get an idea who Mahle is..
http://www.mahle.com/

@ DieselHybrid -

Mahle is one of the largest companies in the supply chain to the European auto industry, though they are active all over the world. 2006 revenue for the Group was EUR 4.3 billion, payroll 38.600 employees spread over 80 manufacturing locations. So no, Mahle is not a fly-by-night garage outfit.

They are best known for their dominant market position in pistons and filters, but they have expanded into air handling and will soon be entering the turbocharger market. Their recent technology demonstrator engine was intended to show off the breadth of their capabilities.

When they put out this kind of general press release on a new product, you can be sure they have a product that is mature enough to ship in high volume. The concept of vaporware is rare in German business culture, mostly because there isn't much of a venture capitalist/angel investor culture for start-ups.

Whether Mahle already have an OEM customer for this particular product, I don't know. It's not unusual for such innovations to be exclusive to a single manufacturer for a limited time, which means they are kept under wraps for a while to give that customer a head start.

The German supply chain works a little differently from the one in the US. Delphi was spun out from GM, still its biggest customer. Mahle, Bosch, Siemens VDO, ZF, Getrag, Continental, Hella and many others in Germany sprang up independently.

I sent this article to Mike when I found it on Mahle's website. I went there to research the 3 cylinder 1.2L engine posted here a week or so ago. (I did not realize that Mahle was involved in complete engine solutions.) I would like to suggest that all GCC fans go to mahle.com and download the .pdf files of their customer magazines. These would normally be delivered to auto manufacturers, but they are extremely well written examples of the state of the art at present, and will provide valuable insight to those outside the industry. One interesting product shown in one of the magazines was a variable valve timing solution for single cam engines. This is accomplished by having a cam within a cam, so both intake and exhaust timing can be independently controlled. A very cool idea especially for 2 valve engines.

Mahel was not involved in whole engine solutions until they bought Cosworth Technology from Audi AG a few years ago with the express aim of leveraging their Tier One component supplier status to whole powertrains.

Cosworth Technology itself had in turn been created by the purchase and subsequent breakup of Cosworth Engineering (into CT and Cosworth Racing which was sold to Ford) by Audi at the same time as VW bought Bentley and BMW bought the Rolls Royce brand.

All three companies (RR, Bentley and Cosworth) had previously been owned by the UK Defence Conglomerate, Vickers.

Hope that clarifes things!

This looks like the first commercial implementation of the camincam Mahle product.
Below text is copied from the MOTOR TREND 2008 Viper road test article.
"CamInCam-in-Block

Dodge and the SRT gang have managed the seemingly impossible -- variable exhaust-valve timing in a single-cam engine. The system is trademarked CamInCam, which aptly describes how it works. The assembled cam consists of a tube onto which the four double-lobe intake cams are press-fit. In between them, the exhaust cams are pinned, through slots in the main tube, to a second concentric rod. An off-the-shelf hydraulic cam phaser from INA can rotate this inner rod by up to 45 degrees relative to the intake-cam tube, but the Viper is currently only utilizing 40 degrees of that range. Minimal valve overlap makes for smooth, quiet idle and clean emissions, while big overlap boosts power when the hammer's down. Between idle and 3000 rpm, depending on throttle position, the overlap increases to the maximum amount. The system is less expensive than two or four cam phasers on a DOHC engine, so expect to see this technology spread among other high-end OHV engines."

If I recall right, Mechadyne in the UK came up with the cam-in-cam design. Perhaps Mahle licensed it or they came up with something similar on their own.

Yep, Mechadyne did the cam in cam that allows true Dual In/Ex VVT on a single cam in block engine.

However, the application above has nothing to do with cams, it is an air control valve located close to the inlet valve in the inlet port which controls airflow in a highly dynamic manner, replacing the throttle.

Apols for the anonymous postings! Browser lost my details.

2000 rpm--30 msec/turn--15 msec/intake stroke
6000 rpm--10 msec/turn--5 msec/intake stroke
with 3 msec switching time, gas dynamic resonance could be done only at low speeds (special for big V8´s).
The system is very interesting specially if faster valves are developed in the future.

@ Mario -

multiple switching events are indeed only possible at low RPM, as indicated. But that's exactly where you most need the torque boost. At higher RPM, there is just one open and one close event per cylinder and cycle.

Btw, your numbers are slightly off. 30ms per turn corresponds to 1800RPM, 10ms to 5400RPM. Moreover, the intake stroke typically extends well beyond 180 degrees; 230 is not uncommon, because valve lift is roughly sinusoidal. In PFI engines, the negative valve overlap is minimized to limit HC emissions. This is not necessary in GDI engines, especially if they are boosted.

@ Mario -

sorry, I goofed up. 2000 RPM does correspond to 15ms per stroke.

You're right to point out that engines with high displacement NA engines (3.0L and above) would benefit most, because they spend most of their life in a severely throttled state. However, even a 1.5L engine suffers significant throttling losses when near idling.

By opening the LTV after the poppet valve(s), the additional vacuum pressure increases the inrush of fresh air into the cylinder, permitting more vigorous mixture formation and higher torque levels when those are needed. In this mode, the last LTV close event occurs at the same time as or after intake valve close.

Conversely, closing the LTV before the poppet valve(s) do(es) reduces the pressure and temperature of the charge mass already in the cylinder, such that peak cycle temperatures and NOx formation are reduced when torque demand is moderate. In this context, the LTV may be opened prior to or simultaneously with the poppet valves.

Rafael, thanks for your explanation , but I´m still a little confused.
It´s possible to regulate the amount of income air in the cylinder with the LVT working in a PWM (Pulse Width Modulation) mode between displacement limits, up to here OK, but ¿is there also an effect of supercharging due to dynamics of the air flow?
¿Is the LPT able of retaining the vacuum between itself and the intake valve from one intake stroke to another?
if it isn´t that vacuum is "lost" (this in the case when LPT closes before than the intake valve) and it implies a decrement in yield.
¿Is there a connection with others cylinders?

@ Mario -

afaik, the LTV is not gastight. Any beneficial pressure differential across it in the closed state quickly dissipates. The cylinder must use it right away or lose it.

Any supercharging due to control of gas dynamic effects will apply only to the cylinder currently in its intake stroke. Opening the LTV late is the easiest way to achieve higher air mass in the cylinder, but it sets up a fairly violent tumble motion. In a GDI engine with a medium or high pressure common rail, you can wait for that too calm down before you inject any fuel.