Comparative motor gasoline, diesel, hybrid and hydrogen 2020 (Source MIT)

[Christophe]

ecological comparison of different engine technologies for engines to 2020 horizon ie 6 the following technologies:

a) Petrol
b) hybrid Essence
c) Diesel
d) Diesel Hybrid
e) hydrogen fuel cell with fixed reformer
f) fuel cell with hydrogen onboard reformer

... Science & Avenir document from June ... 2003 and inspired by a study by MIT (which has surely evolved in 13 years ...):

My analyzes (in 2004)

A misnomer wants called hydrogen engine engines based on a Fuel Cell. But some details are necessary:

1) A conventional combustion engine (spark ignition) is able to burn pure hydogen with some modifications for better efficiency and reliability (materials of the chamber, seats and valves, piston, ignition adjustment, etc. ...). The main difficulty lies in the storage of Hydrogen (27 gas is lighter than air and so small that it diffuses in most materials) This type of engine could of course be called Hydrogen Engine.

2) The "hydrogen" engines currently being talked about in the media are in fact based on a Fuel Cell (see the specific pages on this technology for more information) which will "transform" the hydrogen (and oxygen from air) into electricity and water (liquid or vapor).
So there is that liquid water and steam coming out of the exhaust.
The still big possible confusion with the "water engine" (which does not officially exist) because it is not because we reject water that it is what we consume. Is a gasoline engine called a CO2 engine? No of course!

3) Hydrogen is not an energy carrier in any case a power source (assuming we are not talking recess thermonuclear fusion). For as there is no (or very few) present on earth in the single state, we must transform it from other chemical elements, packaged, transported and stored. All these steps consume energy it takes obviously take into account the performance and emission technology or another. This is exactly what an MIT team.
The results are unfortunately (for his defenders ...) not for the fuel cell.

This extract from a Science & Avenir comes from a study carried out by MIT and compares, in 2020, the different propulsion technologies used:

- Gasoline
- Gasoline Hybrid
- Diesel
- Diesel Hybrid
- Hydrogen with fixed reformer
- Hydrogen with board reformer

The author presents the environmental impact for each technology: energy consumption at kilometer traveled (in MJ / km) and emissions of CO2 (in grams carbon / km).

He concludes that environmentally, the diesel hybrid can strongly compete with the car fuel cell (more econological in all cases with a CAP reform embedded). Economically there is a good chance that the diesel hybrid is much cheaper than the CAP vehicles (especially re-board). The diesel hybrid is the most econological currently available vehicle.

Especially as the cost and the technological development of diesel hybrid is already developed, which is far from the case of PAC! These are just a macroeconomic concepts that hold back its market launch.

The 7 modes of hydrogen production.

Here are 7 possible means of production of hydrogen energy:

Reforming of heavy hydrocarbons to steam

Reforming of light hydrocarbons

Biomass gasification

Gasification of coal with water

thermolysis

electrolysis nuclear

renewable electrolysis

Read also: new-transport / engine-a-hydrogen-with-or-without-carbon-t2163.html

[Adrien (ex-nico239)]

I'm not sure what to raise but I heard today on TV (TF1) that finally diesel cars would be preferred once again to gasoline cars because less polluting.

And I learned at the same time that gasoline cars "benefited" from a penalty for pollution.

In short, I do not understand anything

[Janic]

In short, I do not understand anything

gasoline vehicles, like diesel, have a free exhaust (burnt gas). The strong rejection of diesel Nox, particulate, has led manufacturers to add filters that are quite efficient, but expensive, which on a truck represents only a tiny part of the price. but on small vehicles the additional cost becomes important according to the price of this one. It is therefore a game of cat and mouse where the requirements follow a sort of "fashion", more or less ecological and economical. It suffices for these same gasoline manufacturers to add other accessories to reduce these emissions and gasoline takes over the virtuous head in terms of direct pollution, but less virtuous on the industrial level which must manufacture these accessories ... by polluting, obviously. !