China’s GAC Introduces New Car Engine That Runs On Toxic Ammonia

While the world is looking to get away from internal combustion engines (ICE) and towards battery electric vehicles (BEV) or fuel cell vehicles (FCVs) for cleaner emissions, China-state owned Guangzhou Automobile Group Co. (GAC) appears to want to do it all. During its annual technology showcase, the Chinese partner to Toyota showed off an engine powered by ammonia. While it’s not the first ever to use the rather toxic fertilizer as a combustible fuel, it would be the first to use it outside the shipping and trucking industries.

It seems that’s what GAC has been able to produce, an engine that has a high-enough cylinder pressure to prevent some of that excess nitrogen from being an issue. The 2.0 liter I-4, according to GAC’s Qi Hongzhong via Bloomberg, produces around 161 hp with a 90 percent reduction in carbon emissions when compared to “conventional fuels.” Does this mean we’ll see more ammonia-powered ICE vehicles in the near future? Probably not and it’s more than the nitrogen byproduct it creates.

There are two major hurdles for using ammonia as a fuel source. First, is the obvious one in that it’s a toxic substance. Ammonia is a solvent and can dissolve alkali metals and enough exposure of ammonia in gas or liquid form can lead to death in both humans and animals (it’s the leading cause of fish kills, according to the EPA). That’s why it’s been considered as a diesel fuel alternative for the transportation industry as that sector is already able to handle the distribution and transportation of toxic substances. It’s also used in rocket engines, which is another industry that is used to dealing with toxic substances as fuels like hydrazine and UDMH (which is also known as “Devil’s venom”). The most famous use of ammonia as a rocket propellant was the X-15 rocket-powered aircraft, which was flown to 4,520 mph (or Mach 6.7 at its 102,100 feet altitude) by William Knight.

While you may associate ammonia with its high nitrogen-containing cousin, ammonium nitrate, ammonia is actually rather hard to use as a fuel in something like an ICE vehicle. The liquid form of ammonia is slow burning but has about a third of the energy density of diesel fuel at 37.95 kWh/gal (about 0.88 of a gasoline gallon equivalent). That slow burning property gives it an octane rating of 120 with a flash point of 270 degrees and an autoignition temperature of 1,203.8 degrees. Gasoline, by contrast, has an energy density of 33.7 kWh/gallon, a flashpoint of -9 degrees, and an autoignition temperature 1,135 to 1,550 degrees between 87 and 92 octane.

When it does burn, it is a carbon-free emission and produces zero CO2, zero hydrocarbons, and zero soot. Don’t celebrate yet, without an engine using a high compression ratio or boost, it does release a lot of nitrogen into the atmosphere which leads to ammonia and ozone being made in the atmosphere which can lead to acid rain and impair our ability to breathe. That’s why we’re rather doubtful that this is a meaningful development. As BloombergNEF’s head of transport and automotive analysis, Colin McKerracher, stated, “Ammonia is hellish to handle, I can’t see it taking off in passenger cars.” With its toxicity issues, there just isn’t an infrastructure that exists to even fuel these engines. Even though hydrogen has a tougher time when compared to the EV charging infrastructure network, it would potentially be far better to use ammonia in hydrogen production rather than use as a combustible fuel for ICE vehicles.