Spotted: new Mega City in the wild

We couldn't help noticing this bright tangerine new-style Nice Mega City electric car, parked in central London's busy Wardour Street the other day. The lack of vendor livery suggests it might even be a customer car, rather than a demonstrator or promotional vehicle.

So that's one sold, at least.

The restyle works really well, we reckon. The new car looks a lot more attractive from the side, particularly where the swoopy curve has replaced the old angular chop around the C-pillar. The new rear side-window radius echoes the curve of the screen pillar, and gives the daylight opening a cohesive symmetry. Shame about the yawning fist-sized voids betwen the tops of the tyres and the wheelarches.

We peered inside, as you do, trying not to look like we were about to nick it. The interior looks to have much the same neat but rather flimsy centre console as the old model.

Judging from Car Magazine's recent test drive, the biggest complaints we had when we drove the old car last year - lack of acceleration beyond 30mph and "crashingly bad" ride quality - still remain to be fixed. Still, one thing at a time.

Scottish hybrid system makes for a better BMW

Anyone with an ounce of engineering sympathy will feel a natural suspicion of petrol-electric hybrids like the Toyota Prius and Honda Civic IMA. Transforming energy from one form to another is generally a wasteful process, shuffling backward and forward from one to another doubly so. In the Prius, regenerative braking followed by assisted acceleration is a case in point. Kinetic energy of motion is first transformed into electrical energy by the generator, and this is then converted to potential energy in the battery chemistry. On acceleration, reversible chemical reactions in the battery release electricity, powering the motor to build up kinetic energy once again. It’s a complicated and loss-prone round-trip. Bad, therefore, from an engineering standpoint.

This messy business is one reason why Formula 1 cars, required to run regenerative systems next year, will be using Flybrid flywheels rather than batteries to temporarily bottle up energy during the slow bits of a lap. A wholly mechanical system with no major energy conversions is just so much more efficient in a world where every erg counts.

An interesting alternative has recently emerged from a Scottish company called Artemis Intelligent Power, exploiting fluid power research done at the University of Edinburgh.

Artemis offers a novel type of hydraulic actuator, which can act as either a motor or pump. It relies on a radial arrangement of pistons with ultra-rapid, digitally switched valves and has a very high claimed efficiency. In other words it wastes very little in turning the potential energy of pressurised hydraulic fluid into rotational mechanical energy, and vice versa. The system is called Digital Displacement.

Interesting for diggers and tractors, of course, but also – surprisingly – interesting for hybrid road cars.

To show off the potential of its new components, the company has butchered a BMW 5-Series and given it a transmission transplant. In place of a mechanical gearbox, driveshafts and differential, the Bimmer now boasts a hydraulic-pneumatic set-up.

Under the car, the engine drives a Digital Displacement pump, pipes carry pressurised hydraulic fluid rearward to the back axle, and there a pair of Digital Displacement drives get the rear wheels moving independently.

The pump and drives don’t have to spin at the same rate, allowing the overall computerised system to provide infinitely variable transmission ratios. The engine can spin at its most efficient rate, irrespective of the speed of the car, depending only on the power demands made by the driver’s right foot. We’ve not tried it, but Artemis says the car remains highly drivable and retains its original performance envelope.

Hybrid energy storage is done pneumatically. During braking, the rear actuators switch from drive mode to pump mode, putting energy back into the hydraulic system and using it to pressurise a gas cylinder. When acceleration is demanded later, the energy stored in the cylinder is released back into the hydraulics, driving the wheels.

It’s a neat, purely mechanical system that cuts out the wasteful electrical and chemical steps demanded by a petrol-electric setup.

And the results speak for themselves: on the tough urban cycle the BMW 530i normally scores 20.4mpg; with Artemis’s digital hydraulic system, it scored an independently verified 40.1mpg. Beyond the urban crawl, the standard car gives 29.7mpg on the combined cycle – the hydraulic car achieved 39.6mpg.

And finally, Artemis says its hydraulic transmission is “potentially much more durable, lighter and cheaper than electric hybrids”, with their engine-plus-motor-plus-batteries bloat.

To put it cornily, the land of the rising sun may currently have the lead in hybrid technology, but the canny Scots could soon put them in the shade.

The crushing truth about traffic jams

Oxford academic Nick Bostrom has come up with a startling piece of statistical reasoning that is well worth considering the next time you’re stuck in a traffic jam on a motorway or dual carriageway. It’s not just your frustrated imagination: the cars in the other lanes really are going faster than you.

Of course it’s not always true that you’re in the slower lane, but the law of averages means that most of the time, in most jams, you’ll spend the bulk of your time in the slower lane.

This is a simple result of the fact that the slower lane is the one that tends to have a greater density of cars in it. From the perspective of the jam as a whole, you are an unremarkable random motorist. And since there are more cars in the slower lane, the chances are that you will be in the lane with the most vehicles in it. All travelling slowly. It stands to reason.

The solution, therefore, is clear. To make better progress, don’t sit there like an idiot. Change lanes. And don’t just change lanes when you think your lane is slower – change lanes whenever you see a gap that will accommodate you in another lane, whether or not it happens to be making better progress than your own at the time. According to Bostrom, statistics decree that this will get you out of the jam quicker. Apparently.

Why is it that we suspect Bostrom drives a BMW 3-Series?

All gallons are not equal

We have been exercising our sceptical muscle after reading a recent bit of hybrid bashing:

“Tests by environmental website, Clean Green Cars, show that current hybrids offer no significant CO2 advantage over an equivalent diesel of similar performance. Having tested three hybrids and three diesel models in similar circumstances, the fuel consumption figures showed that diesel models generally used less fuel and therefore emitted less CO2. The results of our tests were:

Toyota Prius vs. Jeep Patriot 2.0 CRD
Toyota Prius: 39.9 mpg
Jeep Patriot: 38.9 mpg

Honda Civic vs. Ford Focus Econetic
Honda Civic IMA: 40.2 mpg
Ford Focus Econetic: 52.7 mpg

Lexus GS 450h vs. BMW 535d
Lexus GS 450h: 28.5 mpg
BMW 535d: 30.6 mpg

The tests involved a return trip from central London to Brighton, which involved a mix of urban, dual carriageway and motorway driving.”

Obviously the first thing to say is that hybrids aren’t a panacea. The wisdom of buying one depends entirely on what kind of motoring you do. Drive on hilly roads or in stop-start traffic and you’ll get great results from a Prius. Slog up and down the motorway and you won’t. So you actually need to think about the kind of motoring you’ll be doing before choosing between a diesel or a hybrid, a mental exercise that Clean Green Cars doesn’t seem to have bothered with. And never mind the air-quality issues of soot particulates and oxides of nitrogen that diesels typically cough out.

The report is also a little surprising in that it seems to suggest that CO2 output is directly proportional to fuel consumption, irrespective of the fuel used. Which, of course, it’s not.
Use a gallon of diesel in an engine and you’ll release about 12kg of CO2, but use a gallon of petrol and you’ll liberate about 10.8kg of CO2 – or about 10 percent less. And on top of that, a gallon of diesel has a worse carbon footprint than a gallon of petrol - it takes more energy to extract, refine and distribute diesel, apparently.

So if a Prius scores 40mpg, a Jeep Patriot would have to achieve better than 44mpg to beat it in CO2 emissions, without even considering the carbon trail hidden behind the fuel pump.

Applying this scrap of knowledge to the Clean Green Cars data, we can see that of the pairs above, only the Ford Focus actually bettered its hybrid equivalent in CO2 emissions.

To this we should add the fact that the Honda is actually a really nice car to drive, whereas uber-economical diesels tend to be about as pleasant to pilot as a dumper truck.

(BTW, this is not the first time we have been left underwhelmed by Clean Green Cars' inability to think things through...)

BMW's Gina slips into something skin-tight

BMW's latest concept is a bizarre confection of metal space-frame and taut fabric. As the company's chief designer notes, it's possible to meet all the structural and safety-related requirements of a car without relying on body panels - as is amply demonstrated by the Ariel Atom (and of course BMW's own plastic-skinned Z1). So the GINA Light Visionary concept uses this notion as a springboard and ends up in the vaguely fetishistic realms of tight, body-hugging, stretchy silver fabric. It even has zippers over its eyes. Sorry, headlamps.

Watch the video and all will be, er, revealed: