Timeandleisure
Senior Member
- Joined
- Aug 26, 2020
- Messages
- 3,912
- Reaction score
- 1,603
- Location
- London
- Your Mercedes
- SL500 2003 R230, E400d 4MATIC Coupe 2021
- Thread Starter
- Thread starter
- #41
Totally agree with your conclusion only trouble is there is no money in it... (not talking about us mere mortals)...Ok. Fuel injectors deliver a fixed amount per shot. Increase the frequency of those shots by increasing the rate of revolutions per unit time and therefore more fuel is used. The more heavily loaded a powertrain is, the more stress (ok, technically strain) is placed on it and therefore more quickly it’s internal lubricating and transmissions fluids are consumed.
Wind resistance from 60 to 70mph doesn’t increase by 36% in the real world. The aerodynamics of modern cars are tuned pretty well to peak efficiency at modern motorway speed limits. So, wind resistance is broken down into a number of factors, in no particular order these are:
block coefficient (the size of hole needing to be punched through the air).
Skin friction, directly proportional to wetted area.
Rate of change of profile.
Stagnation zones.
Parasitic drag.
Then there are road friction, powertrain losses and aero: noise effect losses to account for.
Air is a strange fluid to move through. It takes more energy to get up to a speed (any speed) above the aero effect boundary than it does to stay there. Then, taking all of the points above:
A low, narrow car has to bore a smaller hole than a tall, fat one.
A car with low rate of change of shape (long and pointy) pushes air more efficiently out of the way than a short and fat one.
A car with smaller surface area is less subject to skin friction and, higher in the speed regime, parasitic drag, than one with more surface area (this directly contradicts the long & pointy issue btw).
A car with poorly designed transition zones can leave stagnation areas, where the air rolls like a comber on a beach and attempts to suck the car backwards.
The undersides of cars used to get zero attention, now they have all sorts of aero channels to reduce or eliminate topside aero problems. Those funny shaped wheel arches contribute useful percentages of aero efficiency improvements.
Add all that together and we arrive at (generally) long, low, smooth & sleek cars being the best at aero, however costing significantly more in materials and labour than small, rounded or flattish sided vehicles so therefore being less efficient to manufacture.
None of this is basic physics either..!
So, we then get to the argument: what is best to reduce fuel burn? Well, burning the least amount of fuel per mile of course. So it follows, one can theoretically design a long, low, sleek vehicle with a given engine that, on a straight flat road, for the mass of that car and for a given drivetrain setup, will produce engine revolutions and therefore fuel burn per unit time that equal the fuel burn of a short, fat vehicle at a lower speed. The issue then includes controlling the total units of time that such a car spends on the road, which is determined by its speed. The time taken makes no difference the emissions per mile, but then conversely the emissions per mile also make no difference to the total emissions per journey if the journey takes 15-20% longer in time for a car optimised for a higher cruising speed.
Natural warming and cooling has not always taken millennia, there was a cooling period that took around 2 centuries late in the first millennium that lasted to, well, around now; also there was one around the third millennium BC that again took in the order of several centuries start to finish to begin and then revert back.
You do realise that Peak Oil as a theory has long since been exploded? Oils sands and shales cost more to recover due to the economies of scale of the kit utilised; the infrastructure for a deep sea rig system is enormous in comparison.
The IPCC data and the UN reports are all available by searching online. I’m in a meeting at work so right now don’t have the time to dig it out for you, but they’re publically available.
The reforestation is a natural process not any form of government initiative. Do you think that nature just stops..?! Again, google it. Many articles showing secondary and tertiary rainforest regrowth in surprisingly short timescales.
p.s. came out of a meeting to read your post