Thursday, April 17, 2008


Rocco's twin brother
Last october i declared the death of my old car, which i was very attached to. It was a Ford Focus turbo-diesel station wagon, metallized light greenish, named James, which took me for 200 thousands kilometers [125 thousands miles] (five times the world tour!), in about nine years. We spent a lot of adventures, together, and frankly i missed it, for some times.
James had been substituted by Rocco, a muscular Hyundai Tucson. Metallized gray.
Now, the opposers of the SUV's will get pissed with me, but in the place i live, a 4 wheels drive is practically a necessity.
At first i wanted a gasoline version with LPG (Liquefied Petroleum Gas) plant, but for a number of stupid reasons at the end i bought a 2 liters gasoline and i had it transformed in bi-fuel only in february. Which was a bother, but allowed me to check the exact fuel consumption in order to make a comparison between LPG and gasoline
During gasoline feeding Rocco drinks about 10 liters per 100 km (or 10 km per liter) [4.25 gallons per 100 miles (or 23.5 miles per gallon)], in a mixed type of path including several hairpin bends (from the work place to home there are 10 of them in about 10 km [6.2 miles] with a difference of altitude of about 400 meters [1312 feet]). LPG is a little less efficient, from a consumption point of view, and when Rocco uses this kind of fuel the consumption raise to about 12 liters per 100km (or 8.3 km per liter) [5.1 gallons per 100 miles (or 19.6 miles per gallon)].
Now, in this one should better evaluate the honesty of the LPG station people, because it is kind of difficult to evaluate exactly the amount of LPG effectively given by the pump. LPG, infact, at normal atmosphere pressure and environment temperature is gassiform, and so, by definition, it cannot be measured in liters [gallons] (volume): a gas can infact be compressed, andso the same amount of gas can take up a different volume depending on the compression factor. But a gas, at a certain amount of pressure, mutates in liquid (hence the L of the acronym), and so, by definition, becomes uncompressable, or, in other words, a certain amount of LPG takes up always (about) the same space till when it is in a liquid status. I have the suspicion that some LPG stations i have visited are sly and use minor compression factors and at the end give LPG in a gassified status, giving so a minor amount than the paid much. Anyway i am not complaining here about this: i wanted only to clarify that maybe this problem could make my measurements a little wrong.

cost in euros to drive a distance of 100 miles
with diesel (tested on James),
gasoline and GPL (tasted on Rocco)
Anyway i have a good save of money because, considering the cost of gasoline about 1.40 euros per liter [5.30 euros per gallon] and the LPG about 65 eurocents per liter [2.46 euros per gallon], to make 100km one spends 14 euros of gasoline or 7.8 euros of LPG [to make 100 miles one spends 22.53 euros of gasoline or 12.55 euros of LPG].
But there is some save also with respect of the much i would have spent with the Focus in diesel fuel. With James infact i used about 7 liters per 100km (or 14.3 km per liter) [2.98 gallons per 100 miles (or 33.56 miles per gallon)], and with the actual price of diesel (1.37 euros per liter [5.18 euros per gallon] 100 km would cost 9.60 euros [100 miles would cost 15.45 euros]

Anyway there are also other reasons to prefer the LPG powered instead the traditional gasoline. It is an ecological choice. LPG produces much less pollution than gasoline or diesel. Also about this point of view one should distinguish the type of pollution. With LPG there is a total elimination of micro-powders, that are the one that make our towns unbreathable, and there is also a good decrease of the other polluting substances that are bad for health. It is actually for this reason that bi-fuel cars are allowed to drive in the days of pollution-lock traffic. Then there is the greenhouse effect, widely worse, but that has a much minor direct impact on the air that we breathe. LPG produce much less of this pollution, even if in a less evident way.

There are other types of alternative fuel, that offer some advantages and disadvantages with respect to LPG. I will try to describe them.


It gives immediate advantages for the wallet, because, even if it consumes a little more, it costs much less (if, distance being equal, LPG costs a little more than the half of the gasoline, methane costs a little more than a third). Moreover it pollutes even less under all the points of view. But it gives some problems. The distribution in Italy and in the rest of Europe of methan stations is really insufficient, and one risks to have to procede for long distances with gasoline before he finds the way to make fuel. The fuel tank for the methan is also very big and heavy, and that has the consequence to loose space in the trunk (while LPG tank can be put in the spare tire space, and one must find an alternative place to put the tire, or buy the repair sprays - but... do they work?!?) and an inconvenient distribution of the weights in the vehicle.
Gasoline LPG Methane
CO2 100 90 75
Benzene 100 7 0
HC 100 100 100
NOx 100 47 42
CO 100 93 60
PM10 100 0 0
Values of polluting substances for LPG
and methane,
made 100 the much produced by gasoline,
testing the same distance.
source Quattroruote magazine
From an ethical point of view one should consider also another side. LPG is still extracted from oil, and so, besides of following its costs, also a total conversion to ghis type of fuel wouldn't stop the economical interests in the middle east or the "Wars-To-Terror" fought to control the distribution of the resources. Methan, on the other hand, in nature does not belong to oil, but it has the problem that a big request of methan would surely push towards the extraction from the huge deposits in the ocean floors, where this gas is available in the form of "methan hydrates". Here the gas is "trapped" under enormous pressure in the ice crystals. This extraction would cause some ecological problems. First of all there would be a damage to the eco-systems. Moreover it seems that those crystals decisively helps to the compactness of the continental slopes, and a big extraction could cause the sliding of them, compromising the stability of the continents theirselves. Moreover methan, if brought to athmospherical pressure would expand something like 800 times, somehow growing the atmosphere layers, and increasing the greenhouse effect.


It is possible to produce bio-ethanol or bio-diesel with vegetable cultivation. Even if I cannot provide exact datas now, it looks that they pollute somehow less than traditional gasoline or diesel. Moreover their availability does not depend on the presence of bio-fossil deposits, and it wouldn't be bad to give a big beat to the Lords of the Wars. But, the problem is that that production needs huge extensions of land to cultivate the vegetables for the transformation. So much that this type of production would compete with the cultivations for food, whici is obviously not a good thing.

Hybrid power

Already some models are circulating with this type of power. For example Toyota Prius. It is all about an interaction between two engines: one is electric and the other pushed by gasoline power. The electric uses a battery that is recharged thanks to the motion of the gasoline one. The advantage of this mechanism is that, for the power, it is used the gasoline engine only when the requested power and speed make it convenient, while in the other cases, when the gasoline engine performance wouldn't be good, the electric engine would assume control. Moreover there are some tricks to increase the efficiency (to tell the truth i ask myself why they are not adopted on traditional engines). For example, instead of wasting the kinetic energy, the breaking system of the Prius uses it to contribute in the battery recharging. Toyota declares that a Prius can make in this way 28 km with one liter of gasoline [65.84 miles with one gallon], which is atleast 2.5 times more efficient than any other car of the same category. But technology looks like is still very expensive, for now. There is only one model of SUV 4 wheels drive i know, by Lexus, pushed by hybrid power, but its cost is for me unreachable: 60 thousands euros.

Electric power

The problem of those cars is the range and the time for battery recharging. One car that every 100 to 200 km [62 to 124 miles] must be laying for several hours in order to recharge its battery would be in my case totally useless. Moreover, if the environmental direct impact is null (it doesn't produce any pollution), from the ecological point of view they would be convenient only if the energy sources used to the recharging would be the clean ones.


It looks like the technology is ready now. There are several ways to use hydrogen for car power. The most promising one look like the "Fuel-Cell", which is actually a battery very similar to the electric one, that produces electricity, but it uses hydrogen to the recharge cycle. One problem looks like the storage of big amount of hydrogen in the tank of the car. Hydrogen is unstable and it risks to explode, and moreover, in order to provide a good range, one need huge tanks. But i read some place that there is the way to store hydrogen in the ethanol, and resolve it in the moment it is going to be used. The refueling should then be the substitution of ethanol (already used, to be "recharged") with hydrogenate ethanol (that can be used).... i am not confident with chemistry, but if i well understood it is something like that. The advantages of ethanol as a vector is that in this way hydrogen would use much less space and wouldn't be unstable anymore. The problem is to start the chemical process to separate hydrogen from ethanol when it needs.
Another problem is that hydrogen cannot be found in ntaure but it must be produced breaking the water moleculas. And to do this it needs huge amount of energy. Fortunately it looks that the solar energy can be efficiently used for this task, and it looks that of thist type of energy we will have plenty for some other million years.
The wonderful advantage of hydrogen is that the "waste" is only pure water, which is not polluting.
Anyway nowadays there is no commercial model of car available, not to mention the unexistent network of distribution of this gas.


Not being able to avoid the use of a car, the choice that i considered more convenient, both from the economical point of view and from the ethical one, has been LPG. Unfortunately i am not a scientist and i couldn't say if the sources that i quoted (and the ones that i silently read) are or not reliable. I found on the net also some documents that speak ill of any alternative source of energy for car power, but i have the suspicion that these articles had been directly dictated by the oil lobbies. Anyway i decided to trust who says that LPG is not the ultimate solution, but atleast it is a step towards a world a little cleaner... ehm... a little less dirty.

The plant on Rocco is by BRC. It is a toroidal tank, fixed on the spare tire space. Its capacity is 61 liters [16.12 gallons], but the current European laws for security allow to fill it only till 80%, which means a little less of 57 liters [15 gallons] (so, with a range of about 470 km [292 miles]). Driving, i cannot feel any decrease of power by the engine. With the mandatory type system it is possible to run through the tunnels, put the car on the ferryboats, park in any parking till the first level underground. The plant costed 2000 euros minus 350 euros as a state contribution for ecology.

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