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False Fuel Consumption Claims


Wass
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A common theme which seems to run on forums for hybrid vehicles and in magazine articles too is how the manufacturers and government fuel figures are at variance with those figures which may be arrived at during a test drive or during ownership.

Having driven a hybrid on and off for 2 years , I can understand how it may be reported that there is a difference between government/ manufacturers claims and "real World" ( as they are sometimes referred to) figures.

I drive 35 miles to work on a slow moving rural A road and over a period of time, I have devised my own style of driving which returns fuel consumption figures which are very close to or better than government /manufacturers figures. So that dispels the myth that "real world" figures are different to manufacturers/government figures.

When I first started to drive that particular route, I was driving in my " usual" style which I considered to be reasonably quick but within the law of the land ; overtaking slower moving vehicles where possible and maintaining a smooth pace with no sudden, sharp or late braking. The result was an average journey time of about 55 minutes and fairly unremarkable fuel consumption which was nowhere near the manufacturers/ government figures for the vehicle.

My journey time, driving in my new style, is still about the same:.sometimes its a bit less than 55 minutes and sometimes its a bit more. I tend to set out 5 minutes earlier and arrive about 5 minutes earlier but miss a lot of the heavier traffic most days. I have occasionally reverted to my original style of driving which I would have called normal and I see that I arrive at the traffic lights at mile 34 in much the same time....about 3 car lengths in front of the heavy lorry ( who has been happily doing 40mph in the 30mph camera van patrolled villages) which I overtook at mile 5. On the occasions that i do revert to my previous driving style, I immediately notice the mediocre fuel consumption figures.

Perhaps the manufacturers should give lessons on how to drive hybrids? More importantly, perhaps the manufacturers should give lessons on where to drive hybrids. I have never obtained any motorway/ dual carriageway fuel consumption figures which remotely resemble those hybrid manufacturer/government figures. More to the point, I have actually come close to or exceeded manufacturers/government figures for modern automatic diesels on motorways and duel carriageways with both an Audi and a Volvo. My conclusion is therefore perhaps a little controversial: choose your car to suit your journey if fuel economy is foremost in your mind.

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What you pointed out is very true! the government and car companies paint both Hybrids and Diesel cars as extremely economical by a large margin compared to pure petrol counter parts leading to the public jumping on the Hybrid or Diesel band wagon without asking if those cars actually suits their daily commute route to work or driving style. If one lives and works in a densely congested place like London with lots of start and stop traffic without going more than 40 or so mph in 80% of the journey then a Hybrid car comes into its zone because the car will run solely on the electric motor during those start and stop thereby using no fuel from the main engine, will be road tax exempt and congestion charge exempt too so this car will be a win win for someone living and working in the city. If ones daily commute involves more than 70% open road or motorway driving then a hybrid will be a waste of time because for a start the car will run more on the engine than the electric motor and those hybrid batteries are heavy so one will be carrying around extra weight around which will result in more fuel consumption. A 2.0 TDI diesel will be the opposite of a CT200h as 2.0TDI will be in its sweet spot on longer motorway journeys i.e 60 – 70mph cruising but wont be any more economical than a 1.6 to 1.8 litre modern petrol car in start stop driving as diesels are heavier than an equivalent petrol car so it takes more effort to move the car from a stop. This is why you hear diesel drivers complaining about not getting the 50-60mpg quoted figure. because that’s a combined mpg figure not an urban (town) driving figure. And diesels are also a bit more expensive to buy at the pumps and slightly expensive to service so a cheap car to run starts becoming expensive to run. So I do agree with your comment about choosing your car to suit your daily journey/commute. It’s simple; if 60-70% of ones driving involves motorway or open road then get a diesel if you want the economy. If 60-70% of ones driving involve start/stop with driving speeds not exceeding 30-40mph then get a hybrid if you want the economy. But what people forget is modern day petrol powered cars are getting better and edging towards mpg figures of hybrids and diesels e.g. 2011 ford focus 1.6 litre achieves 47mpg if this car is driven sensibly you can get 3-5mpg more taking it up to 50-52mpg. A Toyota Urban cruiser will give 50mpg from its 1.3VVT-i engine will hit a reasonable 110mph and it’s a spacious car so as you can see petrol is catching up. and both of these two examples will be cheaper to by from new than both an equivalnet Hybrid or Diesel car which returns the same mpg.

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  • 1 month later...

Thank you all very much for your comments and opinions...... I was particularly fascinated by the 'Pulse and Glide' info, although everyone's comments have been both informative and helpful.

Firstly just to let you know, I carried out my own test today by driving the car to a town approximately 15 miles away thereby warming the engine. Upon my return, I refueled and drove back at a steady 50-55 miles per hour on a smooth dual carriageway. I did in fact see consumption while going down a slight hill touch 41.8mpg confirming that these figures probably are in fact achievable. I noticed someone commented on temperature also being a factor, so maybe at a pleasant 20 degrees as per manufacturer's tests the petrol may also burn leaner, again increasing this figure further.

I take on board what many of you have said about the conditions in which these figures are obtained by the manufacturer and I suppose driving in this manor today and achieving the MPG's that I did, didn't exactly suprise me, and that's probably the whole point to my initial post.......

It's not that I thought there was no way on god's green earth that these numbers could possibly be achieved, it's just that with Lexus, the gap seems so vast between maximum MPG and 'real world' MPG, and from my experience at least, the extent of this gap seems far greater than those quoted by other manufacturer's..... and that is my niggle!

However, at the end of the day my wife likes the car and feels very comfortable with driving / parking it, size, comfort, etc.... So I guess that's all that matters. Although I personally still prefer driving my Mercedes S Class, I think as an SUV the RX450h was still the best choice for us. In Obsidian Black with Cream Leather, I think the car looks understated and elegant, it has the softest leather I've ever found in any car and a similar spec new Mercedes ML (which by the way felt quite cheap inside) would have cost £20K more!

Thank you all once again for taking the time to share your thoughts and knowledge.

Allister

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