I also went 25 mph on an interstate at 2:00AM in Texas (Very flat). I was in no hurry to go anywhere but between fill ups I did 25 mpg. I could have done better but I did have a small load on the Pick-up (and the weight of the engine and truck worked against better fuel economy).
Since the 1960s the way American Cars improve fuel economy was through cutting back weight. Prior to the 1960s most cars were design to have air flow through the car even if the windows were up. Thus such cars had tunnels in them between the outer body and inner body where air flowed from the front grill to air inlets in the car. Once the car was stopped you had no air flow, but it was almost as comfortable as A/C if the car was moving. A/C started to be introduced in the 1960s, by the 1970s Cars were designed with A/C in mind (the old force air system was abandoned as cars lost the weight of having two sets of metal for the Air to flow through. While A/C consumed power (And thus require more power than a car without A/C) the use of A/C permitted the cars to be lighter for no need for a force air system of tunnels in the body. Remember when you looking at fuel economy, look at the WHOLE SYSTEM not jut one part of it. In the Case of A/C, A/C uses power (which requires a bigger engine) but once you design a car around A/C you no longer have to design tunnels for a force Air system and thus the car can be made much lighter which permits lighter cars and thus better fuel Economy.
The problem is since the 1970s most ways to trim weight off a car have been done. Thus the next step are more fundamental than taking off weight. The key is better running engines, more efficient engines, better engine-Transmissions- Drive Wheels systems etc. In many ways electronics introduced in the 1970s have made cars more efficient than they were in the 1970s but, like weight, most saving were done by the early 1980s.
Standard TransmissionsOnce you have done all you can do as to weight of cars and electric controls, you have to look at the Engine-Transmission-Drive wheel system to improve economy. Except for Electric cars, the best way to increase miles per gallon in regards to the Engine-Transmission-Drive wheels system, is getting and keeping the Vehicle in the highest gear possible and at the lowest speed possible. This is easier on Standards than Automatics for with a standard transmission a driver can leave the transmission buckle every so often, while the automatic will automatically downshift when it starts to buckle. Standards are also lighter than Automatics and use less power to shift gears. A fourth factor Standards provide better fuel economy is that Standards are metal to metal connections so more efficient at transferring power from the engine to the wheels. This greater efficiency means you can often get the same performance out of a standard transmission with a smaller engine than an Automatic, thus the fifth reason an standard gets better mileage, the engine-transmissions set can be lighter (My father use to say if you wanted an Automatic Transmission in a pIck up of th 1950s and 1960s you had to go with a V-8, if you wanted a six cylinder engine you had to go with a Standard do to this difference in performance between automatics and Standard transmissions, starting in the late 1970s the same rule applied to Four Cylinders engines and V-6s, never buy an Automatic with a Four).
HybridsIn Electric Cars (including Hybrids) the issue is different (Through the key is using the generator motor the least). In a hybrid, you have an electric Generator that provides power to the Electric Motors on a wheel (or Wheels). Notice no trans-axel, no transmission in the conventional sense of those terms. The Gasoline or Diesel engine is nothing but a generator that provides power to the wheels AND excess power to charge the batteries (When the Batteries are fully discharged). The batteries provide any extra power needed that the generator can NOT provide itself (once charged). For best fuel economy the Generator is run at peak level for greatest efficiency, and than cuts off when the batteries are fully charged. The Car then operates on the Batteries till extra power is needed OR the Batteries need to be charged.
Thus Hybrids improve fuel economies in several ways, first by lighter weight. The light weight comes in many forms as follows:
1. No transmission or trans-axles, through offset by the extra weight of the Electric Motor on a wheel.
2. Much Smaller engine which is lighter than a conventional engine.
Thus the whole Engine to Wheel system is lighter, through this is offset by the weight of the Batteries and the Electric Motor. You must understand in a Conventional Engine-Transmission combination the engine-Transmission-Drive Wheel system must be powerful enough to keep up with traffic at peak traffic situations (Such as entering a freeway at rapid acceleration). The problem with this is most cars only need this peak power less than 5% of the time, most times the car is just sitting in traffic, of going along at a steady pace both of which requires a lot less power than entering a freeway (and most of these times is just idling). This is complicated by the fact most engines are design to be most efficient at full Acceleration, but used predominately at much lower levels of Acceleration. Please note when I use the term "Most Efficient" I mean that point where the engine provides the most power for the fuel used NOT the best fuel economy. Fuel economy is more than an efficient engine, but that engine tied in with its drive train. Thus most efficient for fuel usage is when the engine is operating at its lowest fuel usage for the bare power needed (See the paragraph on Standard transmission for further information on this situation).
With a Hybrid the extra power needed in Freeway situations is provided by the Batteries and generator working together. The Engine can be made smaller for it can be set to run AT ITS MOST EFFICIENT SPEED, for its is NOT tied down with a Drive Train, but being used to provide electric power to the Electric Motor, and any extra power being produced being used to charge the batteries.
Thus a Hybrid save fuels in the following ways:
1. Less weight do to NO transmission and mechanical drive train (Through this is more than off-set by the weight of the Batteries).
2. The Smaller engine is lighter and save fuel economy (again off-set by the Batteries and the Electric Motor).
3. The Engine/Generator is running at its most efficient speed with 25-50% of its excess power being saved as energy in the Batteries.
4. The Engine cuts off when the batteries are fully charged and they is no need for more power than can be provided by the batteries (Such as cruising down the highway).
Other ways to improve fuel economyGiven the above what is the "best" way to improve fuel economy? If you want the speed and performance of todays large engine cars that is the Hybrid. But there is another way, that is REDUCING PERFORMANCE. If people will accept a lower level of performance, you can have a even larger increase in fuel economy than from Hybrids. For example if you were to use the Hybrid's gasoline engine tied in with a six speed manual transmission (and ditching all the Electric Batteries and motors) you will get even better fuel economy than the hybrid does today BUT THE ACCELERATION WILL TO 1/2 to 1/4 of today's cars (and top speed will be much smaller). Why would fuel economy be the same? For you will be using the same amount of fuel but hauling less weight (i.e. no batteries).
I am sorry I do NOT see Hybrids as the final say in the issue of improving fuel economy, for going to even smaller cars and engines will do the same or better . The chief reason for the problem is the in-efficiency of Batteries as an electric Storage device, Batteries are at best 25% efficient. i.e. for every 100 watt of power you put into the battery you get 25 out of it. Fuel Cells are better at 50% efficiency with fly-wheels getting almost 90% efficiency. The problem is Fuel Cells are just starting to be made let alone used while Fly-Wheels are even more expensive and if one should break in an accident just a Killing machine (Thus I foresee Fuel Cells being used But NOT Fly-Wheels). The ideal combination is a gas turbine generator combined with a Fuel Cell (Which I see being adopted in the Future but for high end users only, i.e. Military/Commercial use not commuting use).
Volkswagen instead of opting for a Hybrid has done its research in direction of smaller and lighter cars with much smaller engines for maximum fuel economy. VW thus has had a 235 mpg demo car and a 3 liter of Gasoline for a 100 in production (Through NOT sold in the US, this is the Lupo Diesel). These promise to provide much better fuel efficiency than Hybrids (even Gas-Turbine-fly Wheels Hybrids). You may be only going 25 mph, but at least you will get to work at a price per mile you can afford.
For more on the 235 mpg CONCEPT CAR (This was NEVER intended to be produced):
http://www.ultimatecarpage.com/frame.php?file=car.php&carnum=1316http://en.wikipedia.org/wiki/VW_1-litre_carhttp://vw.co.uk/new_devs/one_litreThe VW Lupo is now out of production, replaced by the VW Fox in the super mini Car Market. Neither the Lupo nor the Fox (or the even slightly larger Polo) are imported into the US.
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