Tag Archive | "fuel economy"

How CVT Gearboxes Work

Although by no means commonplace, Continuously Variable Transmissions (CVT) are beginning to appear on more and more cars. The thinking presumably is that, given the rise of hybrid and electric vehicles, they are more efficient and thus more economic.

Most CVT systems replace traditional gears with a pair of pulleys – one for the engine and one for the wheels. They are linked together by a metal belt. Because the diameter of the pulleys changes the effect is of having an infinite number of gears.

In regular gearboxes the ratios are predetermined to whatever the manufacturer requires the in-gear performance to be – longer or shorter for acceleration or economy with the engine speed rising or falling accordingly; this is what we’ve all grown up with. With CVT the ratios change which allows the engine to maintain it’s most efficient speed thus making the car more economical.

Switching a CVT ‘box from auto to manual has the effect of fixing the ratios and allowing the driver to select a gear just like a regular transmission but to the detriment of the efficiency of the car. The only real advantage of doing such a thing is to maximise engine braking when descending a steep hill but, after a couple of seconds, the on-board computer should recognise what’s happening with the descent and switch to a lower ratio anyway. With CVT it is probably best to leave it to the car.

At this point it is worth mentioning some caveats to this. On the face of it CVT gearboxes are the way to go but Motor Blogger isn’t so sure. Certainly, the way the car proceeds is at first slightly odd. Under acceleration the engine note rises and kind of stays there and, because, economy is at the helm, progress doesn’t seem a brisk as with conventional gears.

This gearbox will suit drivers who have no interest in cars. They see them as just being transport and they will require the best of economic choices. Keen drivers might not be so easily pleased and I would suggest it will be harder to prise them away from their regular choices.

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Happiness is an abstract concept. Curiously, you can feel it but you can’t touch it. Our cars make us happy but this euphoria evaporates almost from the minute you pull out and enter traffic. This is when even the most benign suburban streets can turn into a war zone.
As if life wasn’t tough enough, the average motorist has a lot to additionally deal with. Poor road surfaces, rotten weather and the rules of the road all seem to conspire against drivers; and yet these inconveniences pale into insignificance when compared with the bane of our lives – other drivers. The French philosopher, Jean-Paul Sartre, once said that “Hell is other people”. Clearly, at some point, he has driven in the UK.
People: stop and think for a minute. What sort of driving personality are you? Some of you will be careful, others volatile. Perhaps there are some who should be locked up for their own good. Is that a devil or an angel on your shoulder? Watch the video and seek your inner self. Maybe it’s time to be a little more charitable to each other and just maybe that might help to reduce the dings and scrapes of modern motoring. Feel the love on the streets and be happy.

This post has been sponsored by Quotemehappy.com but the thoughts are our own.

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Are We Done With Diesel?

Until recently I owned an Alfa Romeo 159ti with a five cylinder 2.4L diesel engine – the most beautiful car I have ever possessed. Sadly, it wasn’t very economical and the sheer weight of the engine over the driving wheels meant costly tyre bills. The bulk of the engine also compromised the handling of the car, something I didn’t consider when buying.

I blame myself of course but I also blame the sales person. Neither of us properly assessed my driving needs or matched those needs with the correct model. The customer is not always right. At the time, diesel was king and economy the thing. I thought I would save money in the long run. Unfortunately, I didn’t do many long runs. Selling a long distance cruiser to someone who’s motoring mostly takes place within a fifty mile radius of his home on the basis of fuel efficiency was a mistake and it’s a common error. I should have selected a petrol version.

Lately there seems to have been a bit of a backlash against the oil-burners and the problem seems to be with the diesel particulate filters (DPF). While this system acts as a ‘soot filter’, to prevent unburnt diesel particulates from entering the atmosphere, infinite quantities cannot be held indefinitely and so a cleaning cycle is initiated by the engine management system, which heats the exhaust system to such a high temperature, the trapped particles simply vaporise.

What most unwary buyers fail to note is that for this cleaning process to work, the engine needs to be under a continuous load requiring the car to be driven at over 40mph for at least ten minutes. This is unlikely to occur with many urban motorists who will, in due time, find a little lamp glowing on their dashboard which is telling them their DPF is choked with soot. At this stage a visit to the dealer may well be needed, incurring extra expense and kissing goodbye to any putative fuel savings.

It isn’t fair simply to blame the dealers though. European legislation must also carry at least some of the can because those over-paid log stackers do not take into consideration the environmental cost of maintaining (or replacing) a diesel engine’s emission-controlling components or, indeed the excessive cost of diesel fuel.

Drivers must also acknowledge that, although diesel cars are way faster and smoother than oil-burners of old, the high cost of emission control components – and other ‘wear and tear’ items such as fuel pumps – can be a lot higher than those fitted to a petrol engine vehicle. Not only is petrol cheaper than diesel but the cars are too.

It is becoming increasingly clear that we have fallen out of love with diesel, especially with the electric revolution just around the corner. Unless you’re a high-miler, diesel no longer makes sense.

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