Otherwise, the only real innovation here is marrying a boxer config to diesel combustion. Subaru had to do that because all of its vehicles are designed around the boxer concept. There are definite advantages in terms of center of gravity, pedestrian crash safety and especially, engine vibrations.

However, it's also an expensive configuration: you need four camshafts and two timing chains for a DOHC layout vs. two camshafts plus one timing chain for an inline four.

wood is a natural fiber composite. Individual fibers may break but transverse cracks don't propagate. The mechanical failure mechanism is delamination, either parallel to the fibers or between the layers in a plywood construction. The latter also avoids warping.

Solid wood members will also warp or delaminate if they dry out, if only because of the internal stresses that sets up.

Moreover, the joins between components tend to be weak spots, that's why master carpenters use techniques like mortice and tenon to avoid glue, nails and screws.

and you know this because...

How about this music instead?

Btw, clothing with integrated air cushions is on the market, as are big cruiser motorcycles with an air bag.

[www.windmeadow.com]
[video.google.com]

big rotaries are interesting, but really tiny ones even more so. Not for vehicle propulsion, obviously, but they just might replace the batteries in your laptop!

[www.me.berkeley.edu]

this *is* a diesel engine with uniflow scavenging using side ports instead of poppet valves for both intake and exhaust.

In the perspex model, the cylinder end with the single row of large cutouts represents the intake port, while the other with the two rows of small cutouts represents the exhaust. Note that the inner piston on cylinder #1 (on the left) handles the intake port there while the inner piston on cylinder #2 handles an exhaust port.

I can see no obvious reason why they decided against a fully symmetrical design, which would have positioned both exhaust ports close to the turbo.

This thing looks like a forklift truck from a minimalist designer.

large two-stroke marine diesels use the piston for to manage the intake port and hydraulically activated poppet valves for the exhaust.

This engine uses ports for both intake and exhaust. The oil film deposited by the piston at the exhaust port does get burnt, producing blue smoke and coking.

Golle Motor AG has suggested using special coatings (e.g. molybdenum sulfide) to avoid oil-based lubrication of opposed piston engines altogether, but such coatings are very expensive. They also greatly increase both friction and blow-by losses. The company's web site is in German.

[www.gollemotor.ag]

the gain comes from achieving a 2:1 stroke:diameter ratio without excessive piston speeds at high RPM. Also, uniflow scavenging is more efficient than other strategies for two stroke engines.

[home.arcor.de]
[www.propulsiontech.com]
[www.sae.org]

@ SRekaugh -

the long rods are always in tension, so there's no risk of buckling. Besides, diesel engines generally don't run at 6000 RPM - the fuel needs time to ignite.

The inner pistons actually use a partial rather than a full piston pin, this reduces lateral forces on the piston liner. It only works because the boost system always keeps the pressure in the combustion chambers above that in the crankcase.

Presumably because of the target application in military UAVs, the company has kept a number of important details private. In particular, thermal problems with the pistons had been the primary reason why R&D in opposed-piston engines was discontinued decades ago.

A few years ago, a small company in Germany developed a carbon-magnesium matrix composite for the pistons of an opposed piston engine intended for light aircraft. Video in German:

[video.google.com]

The point of an entry-level commercial vehicle is utility and low cost of operations. The F150 is not a musclecar.

somewhere on Jalopnik.com, Balsy the five-point harness owl salutes you!

At least I think it's called saluting. Damn ESL...

not weird at all. The 335i uses high-pressure spray-guided GDI to run stratified combustion in part load for the sake of fuel economy. The price for that is that the injector and spark plug need to be positioned very close to one another at a very precise angle, or you get soot like in a diesel. To make room for all that, the valves need to be a little smaller. Also, the main injection is very late (just before TDC) so there is very little time for evaporation and mixture formation. All of this limits maximum RPM and therefore, rated power. The turbos are relatively small, intended to provide torque boost at low RPM. In other words, the 335i engine is optimized for normal road use.

By contrast, the M3 is designed for maximum power density, i.e. a rev limit bounded only by the high expected life of the engine. That means optimizing the whole air intake system for minimum pressure loss (straight ports), the long valves for maximum throat section, the spark plug for minimum diameter and, the valve train for maximum stiffness - all without exposing any part of the cylinder head to excessive heat, which could lead to engine knock, a cracked block or leaking valves. A lot of work has to go into shaving weight off the pistons and connrods, not just to rev easily but also to protect the journal bearings. At high engine speeds, peak stresses in the cranktrain occur not during combustion but at the end of the exhaust stroke, due to inertial forces.

Also, you want fuel evaporation to begin as early as possible to maximize the density of the fresh charge - power is limited by the available oxygen. With GDI, the onset of evaporative cooling is delayed until after intake valve close. This allows the engineers to increase the compression ratio for greater thermodynamic efficiency. However, once you have to enrich the mixture to protect components such as the cylinder head and three-way catalyst, fuel economy is a moot point and extra compression heat is the last thing you want. Besides, GDI pumps operate at higher pressure, so there's more to go wrong and greater parasitic load. For all these reasons, racing engines continue to use port injection.

The Bush administration picked up the engineering talent and created the a new corporate welfare boodoggle called FreedomCAR, as in "you want freedom fries with that? By refocusing the team on hydrogen fuel cells rather than diesels and advanced batteries instead of aerodynamics, the boffins were in effect sent back to square one. This ensured that sales of petroleum distillates would not be threatened during the Bush presidency or indeed, for many years after that.

Chances are, Skoda will build both versions.

[www.urbandictionary.com]

For the sake of damage control, VW's marketing mavens might want to explain what they intend CC to stand for, since it's obviously not a convertible. How about "Coromell Coupe", that at least fits into VW's historical practice of naming its larger cars (except SUVs and the Phaeton) after winds. A night breeze in Baja sounds about right for this particular car.

[ggweather.com]

Note: it's possible this particular fast food restaurant had already reduced its trash removal bill because the service he contracted was already using it for biodiesel production of its own.

How long before we finally get 180+ degree wrap-around rear-view displays based on stitched-together video feeds?

[video.google.com]

I think it's to keep them from getting stolen.

[video.google.com]

Chrysler > Ferrari (stretch versions only)

The IMO - a body that requires unanimity to make decisions - is unlikely to require the use of low-sulfur fuel on the high seas any time soon, precisely because there's not enough available. Ships will therefore have to be equipped with a flex fuel system that keeps LSD and DMX (or worse) in separate tanks. Most likely, additional fuel pumps and injectors will have to be installed as well.

The bigger problem is that many refineries in Asia and certain other parts of the world are not yet equipped to deliver LSD fuel at all. Ergo, ships plying routes to and from the US would likely have to take on enough LSD in the US to cover sailing in US waters on the return trip.

As usual, engineering changes for the sake of the environment cost money. It all boils down to who pays for it. There's also the issue of enforcing compliance out to the limit of US territorial waters using remote sensing equipment. Near the ports, that could be installed at elevated locations (e.g. nearby hills, skyscrapers, bridge bylons), out at sea you'd probably have to use slow-moving aircraft like blimps or helicopters.

[www.landships.freeservers.com]

[microcarmuseum.com]
[evolution.loremo.com]

The Janus configuration is named after the Roman god with two faces. The advantage is that you can fit the engine in the middle of the car, in-between the seats. Also, passengers in the back (e.g. babies, children) are much better protected in the event of a head-on collision.

One downside is that the rear passengers can't see ahead, so at high speeds every bend comes as a surprise - resulting in nausea. There is a trunk up front, but unless the engine is air-cooled, the available space are severely restricted by the radiator and fan.

Conventional two-stroke gasoline engine designs are based on crankcase scavenging and ports. Gas exchange timing is fixed by their position relative to the piston's range of motion. The exhaust port opens roughly 120 degrees after TDC - i.e. after the piston has completed ~75% of its downward motion - to depressurize the cylinder. The intake port opens shortly thereafter to admit fresh charge from the crankcase. This was slightly compressed by the piston during the downward motion, so initially there is a puff of gas that displaces the spent charge (pressure acts before diffusion can). After that, the crankcase is emptied at atmospheric pressure. The intake port closes again before the exhaust port does, but the upward motion of the piston creates just enough pressure to prevent exhaust gases from re-entering the cylinder, but of course residual EGR rates are still higher than for four-stroke engines.

By contrast, a head-scavenged two-stroke uses a full valve train for both intake and exhaust. This means you can implement any valve timing and lift you like with appropriate cam profiles. In particular, it does not have to be symmetric relative to BDC and, the intake valves can close after the exhaust valves do. This is a prerequisite for effective boosting, which in a two-stroke also requires aggressive intercooling. In this particular case, Ricardo also chose to retard both valve timings to achieve overexpansion, presumably to keep things cool enough. As usual, the amount of retardation can be adjusted with cam phasers.

They are using an electro-hydraulic valve train on the research engine so they can simulate arbitrary cam profiles without having to change the hardware. This has been standard practice in cam profile tuning for many years now. Any production version would use a much simpler and cheaper system to switch between two sets of cams (cp. Honda V-TEC, Porsche Variocam etc., though they use an alternate cam profile that delivers partial lift in regular four-stroke mode).

The two-stroke mode is used specifically so the engine displacement can be laid out for the most common load cases and not the rare requirement for very high power. Downsizing increases the fuel economy of gasoline engines by reducing weight, internal friction and throttling losses. The objective is to deliver the same rated power more efficiently, not to give a vehicle more power.