2012-06-17

Direct or Indirect: different injection setups, each one with its own advantages

The adaptability of the Diesel cycle to some alternative fuels like biodiesel , pure vegetable oils (either straight or waste) and ethanol is already known, but due to specific characteristics of each fuel, different fuel injection systems are most suitable for each application.

Indirect injection, more used in older engines, usually has higher combustion temperatures, which are better to handle a vegetable oil due to the amount of glycerin, that is harder to burn completely and thus taken away from biodiesel. Prechamber design also has lower injection pressures, what leads a cheaper hardware to have a satisfactory performance. In the Philippines, it basically remains on the market in older models such as the Mitsubishi L300, Hyundai H100 and Nissan Urvan Escapade.


Direct injection requires higher pressures to get a proper combustion because of the lower temperatures demanding a smaller contact surface between the fuel and the hot compressed air inside the combustion chambers. An advantage from this setup, by the other side, is a reduction in NOx emissions, what Diesels are hardly blamed for.




Ang kaya sa pagbagay ng diesel cycle sa ilang mga alternatibo fuels katulad biodiesel, purong langis ng gulayin (alinman diretsong o basurang) at ethanol na tinatawag, ngunit dahil tukoy na mga katangian sa bawat gasolina, magkakaibang mga sistema ng gasolina iniksyon ay karamihan-naaangkop para sa bawat application.


Indirekta iniksyon, mas ginamit sa mga lumang engine, kadalasan ay may mas mataas na temperatura ng pagkasunogna mga mas mabuting upang pangasiwaan ang sa isang gulay langis angkop sa ang dami ng gliserin, na mahirap sumilab sa kumpleto at kaya dadalhin ang palayo sa biodiesel. Prechamber disenyo din ay may mas mababang pressures iniksyon, kung anong humahantong ng mas mura hardware na magkaroon ng maimis pagganap. Sa Pilipinas, nanatiling talaga nito sa merkado sa mas lumang mga modelo tulad ng Mitsubishi L300, Hyundai H100 at Nissan Urvan Escapade.
 

Direct iniksyon ay nangangailangan ng mas mataas pressures makakuha ng maayos pagkasunog dahilan sa ang mas mababa mga temperatura demanding isang mas maliliit na balat ng contact pagitan ng gasolina at ang hot compressed air sa loob pagkasunog kamara. Ang isang bentahe sa setup na ito, pamamagitan ng iba pang mga panig, ay isang pagbaba NOx emissions, ano ang Diesels ay para bagang blamed sa mga.

2 comments:

cRiPpLe_rOoStEr a.k.a. Kamikaze said...

IDI's are often quoted to have a lesser sensibility to lower-grade Diesel fuel. You might remember when the civilian-spec Hummer H1 started to be fitted with the direct-injection Duramax 6600 while the military Hummvee remained with the old 6500 IDI.

But direct injection actually increases the range of fuels that can be used in the engine, since it can handle more volatile ones that would pre-ignite at a prechamber, such as ethanol and even gasoline in case of emergency.

Johannes said...

I grew up in a farm in South Africa, around some indirect injection Perkins engines in tractors and trucks. Never really had any cold-start issue with them not even in the coldest winter altough they're often blamed for that.