Joseph Chikva wrote:Wrong. I said that if even reduction of NOx isexothermic reaction, their content in entire exhaust stream is neglectably small as 1000 ppm is only 0.1%. And even you would think up how to use that extra energy, its contribution in efficiency would not be significant.
Wrong? This is a direct quote from your post on page 3, post 7 of this thread.
Joseph Chikva wrote:
I am caught up that injecting into exhaust pipe of any media will not make any useful work even if that reaction is exothermic.
That's the statement that caused me to bring up turbocharging. A situation where you can extract useful work from an exhaust stream. Your point about the concentration of oxides of nitrogen is besides the point. If the reaction occurs, it adds heat and work can be extracted. Ammonia isn't likely to produce much NOx but that doesn't change the fact that you could usefully inject fuel into an exhaust stream.
Joseph Chikva wrote:
When you talk about e.g. 2.0 L Ecoboost engine namely displacment gives limitation on air inflow. Turbocharger only expands engine's ability to take more air in comparison with naturally aspirated engine having the same displacement.
And namely this ability defines the quantity of fuel that can be fed.
Give the engine more than this quantity of fuel and you will not get more power. Even if you would reach the stable combustion at very rich mix.
Yes you will, as long as there is sufficent oxygen to at least partially burn fuel, increasing fuel will increase power. Racers run rich all the time. It lowers efficiency versus full burn and increases emissions but it works to maximize output.
Joseph Chikva wrote:
Why are you so sure?
For your reference, the most efficient mode of engine is when that runs at a little poor mix. That can be described by "excess air coefficient".
But that coefficient should not be high due to high pollution of nox as result of oxidation of nitrogen presented in air.
I am asking now, if you are proposing as a fuel nitrogen containing ammonia why your mix "doesn't produce much" NOx?
Sure, running a bit lean is good for fuel economy and emissions. If you run too lean, you get high engine temperatures. Run them high enough and the disassociation rate of nitrogen gas creates the opportunity for production of oxides of nitrogen. Running rich is good for engine life and power. If you can burn more fuel, you always make more power. If you can't burn the fuel, it doesn't make power.
Burning ammonia as a fuel doesn't produce much in the way of oxides of nitrogen because ammonia is less energetic than gasoline and burns at a lower temperature. At that lower temperature, there is less disassociation of nitrogen gas. The enthapy of formation of all of the oxides of nitrogen is much higher than that of water, making them unlikely products. Also, those oxides are unstable in the presence of oxygen leading to a further disfavoring.
If you'd like evidence, I posted a link to an actual ammonia engine earlier in the thread.
And that pretty much wraps up my involvement.