It’s a fact. In the UK the Ford Focus 1.6 petrol engine has a combined mpg figure of 47 mpg with three options for performance. There are diesel options. A BMW new x3 xdrive 20d returns 50 mpg does 130 mph and hits 62 mph in 8.5 seconds. The 30d does it in 6.2 seconds and has combined 47 mpg. You obviously don’t get both at the same time. An Audi Q5 2.0 TDI has a 45 mpg combined figure.
Obviously the Ford Focus has diesel engines but many owners don’t do the mileage to justify the added cost of the car and fuel. Diesel works well in large cars and is the only option in some SUVs.
How do they do it? It doesn’t make sense. We’ll have a look in a minute but first let’s describe the problems.
In 2006 I posted A guide on Renault fuel economy and CO2 emissions on carbuyersinfo. I discovered at the time only tiny petrol engines or fairly small diesel engines achieved less than 130 CO2s. It also had to be a small-sized car. A few medium cars managed it. It needed to be manual or Quickshift, not automatic. It was noticeable Renault’s common rail injected turbo diesels had high power outputs.
So it’s remarkable how economical big powerful SUVs can be.
BMW explain their EfficientDynamics as a combination of auto stop start, brake energy regeneration, electric power steering, optimum shift indicator, lightweight engineering, reduced resistance, low friction fluids and active aerodynamics. The same approach is taken by Audi.
Automatic stop start is easy enough to understand. When the engine switches off you’re saving fuel and emissions. Stop Start can be found on many cars as standard or an option. The question is, is the price you pay for stop start less or more than your fuel savings.
Brake energy regeneration is one step towards solving a problem manufacturers have long been aware of. A significant amount of power produced by an engine goes to driving other motors, the alternator being one plus pumps not to driving the wheels.
Brake energy regeneration collects energy wasted for charging the battery. When your foot is on the gas energy to the alternator is reduced, when you’re rolling or braking energy is increased above the normal level.
The more the alternator and battery can be boosted to drive motors and pumps the more engine power there is to drive the car meaning smaller engines are needed. Which leads us to …
Electric power steering which has been in production on everyday cars for over a decade. Back then they said it saved one mile per gallon. Not a lot in it for you. But multiply it by the 200 gallons you’ve bought per year multiplied by the last ten years and it adds up. It’s especially important for our environment when you then multiply your figure by the millions of cars made and sold every year.
Optimal shift indicators have been available for some time and is now more widely used.
Lightweight engineering has long been an issue in car manufacture from the early days of Peugeot, Renault and Ford. BMW and Audi can afford aluminium at the prices they charge.
Reduced resistance is reduced rolling resistance tyres which are widely available mainly as an option extra. Again is the price you pay more or less than your fuel savings especially as tyres inevitably wear out? Do they actually cost more to manufacture than previous tyres?
Low friction fluids and active dynamics to help your engine reach operating temperature faster are nothing new.
The big difference is large SUVs cost at least twice the price of the bread and butter car the man in street buys. They can afford aluminium and energy recuperation systems. The rest is on most cars or an optional extra.
It will come one day as ABS became standard in 2006 and ESP will be later this year. Legislation to some extent now drives car safety, economy and ecology. All you’ll have to do is decide on style.
I should say I’m not for one moment suggesting and X3 or Q5 is cheaper to run than a Ford Focus. Nothing could be further from the truth. A Focus is way cheaper to own.
Regards
Ralph
