At first glance, the two Toyotas pictured may appear to be the colour red. A serious motoring fundi might even be able to identify them as red mica metallic and solar red, but unfortunately in both instances the viewer would be mistaken. These two cars are in fact green.

The new Auris seen here is a lovely shade of 1AD-FTV turbodiesel green, while the Prius is indeed the rich hue of 1NZ-FXE ETCS-I series-parallel green.

Sounds like a mouthful doesn’t it? Not to worry. In both cases that techno-jargon engine code lingo can easily be translated to ‘low emission or fuel efficient’. In a world that’s slowly suffocating on noxious fumes created by resource guzzling transportation, many motorists are searching for ways to reduce their respective carbon footprints and do their part in earth conservation.

Well here’s two prime examples of such ways. Originally launched seven years ago with a major revision in 2004, Toyota’s Prius is actually old news. But over those past few years this car has led the way in fuel efficiency and pollution reduction, so we just had to see how it compares to Toyota’s latest green offering with all the cutting edge turbodiesel technology available in a modern passenger car.

The challenger here is the new Auris 2.0-litre D-4D.

After spending a couple of days with both cars, the results became very clear to me. Please excuse the pun but it’s really a case of six litres per hundred kays of one, and half a dozen for the other.

I drove both cars over a test period that included fairly equal amounts of morning and afternoon traffic, some highway stuff and a bit of lunch break material in between. Both cars returned such similar fuel consumption results that they’re pretty much on par with each other in this particular category. Interesting, especially considering the vast difference in propulsion methods.

Okay, to be really fair, the Prius did edge out the Auris by a margin slimmer than the hair on your chinny chin-chin. I averaged between 5.8 and 6.0l/100km in the Prius, while the Auris gave me between 6.0 and 6.2. I must mention that I drove both cars as I would normally. No economy run style here. I just went with the flow like everyone else.

Ingenious combination

The Prius uses this ingenious combination of petrol and electric engines to achieve these results. It’s actually one of the eeriest feelings I’ve ever had driving a car. Put the key in the slot and press the ‘power’ button. Nothing happens except for the illuminating of a few dash lights.

However, she’s ready to go. Flick the tiny gear lever into reverse or drive and start moving. Well, hovering actually. Sounds exactly like a golf cart as up to a certain speed and load, propulsion in provided by only the 500 volt electric motor.

But when more oomph is needed for accelerating or overtaking, another electric motor starts the 57kW 1.5-litre petrol engine on the fly, quicker than you can say “green peace”. So whilst driving normally, a 32-bit microprocessor is constantly deciding whether to use electric, petrol or both motors to propel the car. There’s also a nifty display setting in the centre console indicating what’s currently happening between the wheels, motors and batteries in real-time.

The really clever thing though is that the batteries that power the electric motors are charged either by the petrol motor or the driven wheels while coasting. What I discovered is that with exactly the right throttle input at any given time, you can get the petrol engine to drive the wheels as well as charge the batteries at the same time. That’s what the display was indicating to me anyway.

More conservative approach

The Auris takes a much more conservative approach. No electric motors other than the ones that work the windows. It does however utilise the latest in common rail fuel injection technology. Watch your head, here comes some more of that jargon.

The fuel injection system operates under a pressure of 1700 bar in conjunction with a variable nozzle turbo charger, while at the same time an oxidation catalytic converter reduces fuel emissions. Phew, did you get all that? In English that means – fill the car with diesel when it’s empty, drive for approximately 900km, and repeat.

Two different approaches to obtain essentially the same results. What really differentiates these two is the packaging and performance. Auris still has the edge, especially when it comes to overtaking acceleration on the open road. It’s a different story when it comes to image.

Driving a Prius is a blatant statement in eco-conservation. There’s no hiding in this car. You might as well be piloting a flying saucer through rush hour. While on the other hand the Auris allows for complete anonymity.

Think of high profile Angelina Jolie doing her part to save starving babies in Ethiopia versus quiet little Annelie Jooste from Kriel making an anonymous donation to Unicef. Something like that.

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