How Renault makes a 50mpg 7 seater January 11, 2010
Posted by richard in : Technology , add a commentRENAULT and I won our class in last year’s MPG Marathon – a right ol’ result, it was, after 400 miles’ somewhat steady driving.
But how? All down to the Grand Scenic I drove – fitted with the 1.4-litre TCe ‘downsized’ engine.
In Renault parlance, this is a 2.0-litre power-puncher with 1.6-litre fuel-sipping ability. Tiny turbo, no direct injection, Nissan all-alloy block and plain efficiency. It’s a canny wee thing, alright.
Particularly if you want to drive economically. See, its key characteristic is delivering loads of torque at really low revs – diesel-like revs, in fact. Throughout the entire Marathon, I honestly didn’t exceed 2000rpm. And still managed to summit the 1-in-2 climbs dotted through the route.
That tiny turbo allows this; it spools up fast, which is just what you need for eco driving. Here’s traits I exploited:
• Responsive to light throttles
• Ability to select 6th at ridiculously low speeds
• Linearity when modulating the throttle
• Turbo doesn’t ‘run away’ from you
• If you’re genteel, then so will it be
Being eco is about fluid motion. You need to swim along, with not a misplaced stroke, slipping along like an eel. Only with infintesimal control over the fuel being pumped into the engine can you do this.
Tiny turbo engines often produce great figures on the test rig, but plunge in real life, due to the turbo sucking in air like an iron fist, and forcing fuel injection to throw petrol in accordingly. Many people who drive at low revs and in a seemingly eco manner actually get mediocre economy – because of the lack of control the engine seems to have over itself.
None of that with the TCe. If you want to accurately throttle back as far as necessary to maintain pace, you can do. No torque-free gullies to fall into, no risk of being left floundering. It’s almost electric-like in its reponsiveness when you’re taking it steady.
The result of this is 50.3mpg in a 7-seat Grand Scenic. Official.
RenaultSport past to inspire turbo future
Green car countdown January 4, 2010
Posted by richard in : Technology , add a commentIs this the single most important feature a car can have to encourage economical green driving?
It is, no less, an ETA for sat nav journeys. No more than that, either. Eh? The big deal is..?
This: In real time, it tells you what time you’ll arrive where you’ve said you want to be. In this instance, it’s seen on a BMW M3 Edition Coupe, but y’£100 TomToms have the very same function. With a bit of thought, it’s potentially massive.
It’s why I set sat nav to take me home. Now, Lord, even I’m not forgetful enough to forget the route. No, I instead like to know how long it will take.
Surely you know, you may ask? And yes, I do, roughly. But I like exacts, not guestimates. Particularly as, and here’s the key, my eco head sees my speed vary from day to day. Seriously. And it’s sat nav that allows me to do this in confidence.
Say I have 5mins ‘spare’. I’ll slow down a bit. Tweak the ETA. By driving more slowly, I’ll have returned more miles to the gallon. See it as a bit of real-time money-saving. In practice, it means I can be as green as possible and STILL not miss the start to Corrie.
It’s pilot mode. Whenever they’re late, what does a scheduled aircraft’s pilot say? That they’ll put their foot down and make the time up. That’s because planes are usually operating at way less than vmax – they’re flying at the EXACT speed required to reach their destination on time. No faster. No slower. This is, err, plain efficiency – both of time and of resources.
We could be doing this in our cars in the future: plugging in what time we need to be home, and letting the car cap, say, our motorway speed to only that required to achieve this. Perhaps, with layered financial penalties for those who want to go faster, within the realms of legality? Companies in particular would love this, and with vehicle tracking now all the rage, it would be particularly easy to implement.
Folk don’t like being told to do stuff slowly. But, they could be convinced to do it a bit slower, if they knew by how much they’d be penalised if they didn’t. What’s a few minutes here and there, for the prize of 5mpg and a fiver?
The Maestro of the instruments
Audi Q5 economy enough to tyre you out
Fuel economy economical with the truth?
The 58mpg MINI and my turbo engine theory June 28, 2009
Posted by richard in : Green cars , 1 comment so farMINI John Cooper S Works returns 58mpg shock.
Yes, indeed. And a real-life shock, as I proved over the weekend.
I wasn’t doing anything particularly special on this 100-mile journey, either. Simply driving steadily up the motorway.
Listening to Radio 5Live. Hearing Eamonn Holmes interview Steve Bruce. Enjoying the sun. Considering the tactile qualities of Alcantara steering wheels. Normal, everyday stuff.
Yes, my right foot was light, but I wasn’t crawling. Yet, at journey’s end, there the remarkable result was. Boldly blinking on the trip computer. 58.6mpg.
This, from a 211hp turbocharged 1.6-litre… petrol engine! Naughty exhausts and all! Pretty jazz, I reckoned. And yet another tick against my turbo engine theory.
That they’re super-economical when you drive them economically. But thirstier than Richard Burton when on it. Disproportionally so. Jekyll and Hyde. And so on.
Car makers know this. And this is why modern turbo petrol engines always do really well on the official test cycle.That’s something conducted in a genteel manner not dissimilar to how I drove last Saturday.
But what’s real in my world, and the world of Euro-MPG test drivers, isn’t in the vast majority of turbo petrol drivers. Hence, the disparity in economy many report.
It’s a theory I’m going to run with, and put to the next engine, err, engineer I meet…
MINI John Cooper S Works photostream on Flickr
MINI prices and the daily heart-flutter
More on Mini’s classic brochure
Audi Q5 economy enough to tyre you out April 19, 2009
Posted by richard in : Minutiae of cars , 1 comment so farDON’T buy an S line Audi Q5 if you want the best fuel economy possible.
The Q5 scores a Cd drag coefficient of 0.33 – for all engines… fitted with 17-inch or 18-inch wheels. That’s standard and SE, then – not S line, with its great-looking standard 19”s.
In days gone by, this would have forced Audi to publish individual CO2 and economy figures for the S line version. Today, while eco rules are generally tougher, they’re also more lenient in areas like this.
It also means customers can really destroy the mpg, by taking up optional 20-inch wheels. There are air brakes that are less effective.
Me, I can’t deny they look great – but it still seems a shame to undo all the good work done my engineer insider, whom I met on the Q5 launch.
Boasting of the Q5’s low drag, he said it was all the more impressive, considering the 2.65 sq m frontal area. Not particularly aero, that.
How to overcome? ‘We designed in a V-shape, which helps,’ he told me. ‘We also have a smooth roofline and a tapered rear end. The underside is flat, too.’
But Audi prefers not to use complicated solutions such as BMW’s active aerodynamics. ‘We’ve managed to reduce fuel consumption by 15 percent without them,’ my engineer insider said.
Canny. Then, someone goes and ruins it all by bolting on a set of 22-inch aftermarket rims. Dammit…
Fuel economy economical with the truth?
Secrets of the new Toyota Prius
Fuel economy economical with the truth? March 27, 2009
Posted by richard in : Minutiae of cars, What I learned today , 5commentsFuel economy is all nowadays. Not since the 1980s have manufacturers been so intent on producing efficient cars.
It’s all in the name of being green, you see. That’s why we’re seeing the return of the ‘eco special’.
Back in the day, car makers achieved good returns with long gear ratios, economy meters and stripped-out, lightweight equipment levels. Volkswagen Polo Formel E, anyone? Austin Metro 3+E?
25 years later, things are, of course, much more advanced. We have, err, long gear ratios, trip computers and, well, stripped down equipment levels. Audi TDIe, Ford Econetic, etc and so forth. OK… not much progress there, then. But, if something ‘aint broke and all that…
Why this post, then? Because Ford’s revealed some of the secrets behind the eco game in Automotive Engineer this month. See, nowadays there’s far more to it than simply keeping the revs low.
The fuel test cycle may be oft-criticised, but it still takes in a whole host of parameters. Which can be, for want of a better word, massaged.
Here’s 5 revealing ways the new Fiesta Econetic beats the system.
• Every kg saved benefits real-world economy – but only HUGE mass reductions affect the test cycle figures. That’s because ‘inertial weight classes’ are used, each covering around 100kg. This is basically a rolling road with a resistance against it. But… it’s only by shaving enough to move into a new band that you will improve economy.
• Fitting longer gear ratios is expensive. Volkswagen does this in Bluemotions – 1st and 2nd are standard, 3rd to 5th stretched. Far cheaper, says Ford, to simply fit a longer final drive ratio. It cuts 5g/km from CO2 emissions. But depends on having a torquey enough engine to still pull well in 1st and 2nd…
• It’s not hard to make a more aerodynamic car – but it IS costly to produce and fit the bespoke panels required. Ford reduced CO2 emissions by 2g/km, by easy measures. The maker didn’t want any more bespoke ‘workstations’ on the production line, to fit extra aerodynamic addenda.
• An easy fit, you’d think, would be aerodynamic wheel trims. Yes, says Ford – but the redevelopment work in ensuring the brakes behind them get enough cooling air is another matter. That’s why they’re not here.
• The biggest trick to improving test cycle economy is recalibrating the engine ECU. Measures here include reducing the idle speed, as it takes up a big part of the official test cycle. In the future, Ford also expects eco credits for fitting a standard trip computer.
All of this helps improve the official figures. However, only some of it will affect real world economy. Just goes to show, when judging economy cars, that it’s best to look beyond the figures, and what measures are actually employed to achieve them.
Are they test cycle cheats, or real-world benefits?
