Difference between MPFI & SEFI

Well Krishna, EGR is meant for emissions control. As for technicalities, I guess its going to be difficult keeping technical jargon down - that's the nature of the discussion itself. Anyways, will try to keep the language as lucid as possible.

Hello Krishna, 

EGR is for only emissions purposes, it hinder performance and mileage. And some engines like Ecotec L61 2.2 version omits EGR, and legal in California.  

Common man, i bet with our backfires alot of people are learning... i mean we are going somewhere off topic than what the thread is, but that usually happens what say ROHIT. Arn't we all learning already...lol. will try keep things simple. thanks

Well yes with this kind of discussion there is every chance of drifting here and there but then I guess the discussion would not be fun otherwise. So as long as we don't lose sight of the main topic, we should be fine.

Ok, been doing some reading - SEFI is when "injection is timed to coincide with the intake stroke...". So for all intents and purposes MPFI and SEFI are one and the same. Nothing new about it as it has been done for quite some time now. The other MPFI is batched where fuel is injected in batches - i.e., without synchronising with the intake stroke per cylinder - injectors fire for all cylinders for every cylinder's intake stroke - ASP this is what the firing two injectors thing is, partially at least.

hahah, I like the fact how you convey your idea making it sound rite as well as wrong. Smart guy.

Ne how as i mentioned that I will have some solid references to back up what I am saying, literture wise haven't found a positive book which explains about how does MPFI different then SEFI, all it states is MPFI can be Sequential/or batched. Now the question what is bothering me how is that possible, when we talk about sequential system we have driver for each injector(eg: 4 injectors means 4 drivers and so on) but in MPFI mostly I have examples here they say if its four cylinder engine mostly has 2 drivers to run 4 injectors(2 injectors per driver) but then how does the system runs in sequence. I am still doing my research.

But I am 200% sure and bet you any money they SEFI and MPFI is not the same. SEFI is derived from MPFI as batch firing is not required at low rpms, it vaporises fuel at low engine speed hence reduces efficiency. Hence the result SEFI is used more precise and accurate mixture every time.

For general public. SEFI is the best if u have the option. for better response and fuel economy.

For rohit .. i have a report by couple of engineering students who explain the benefits of MPFI and SEFI. Batch firing is must for high performance engines because at high horsepowers keeping the intake manifold wet keeps the air charge cold and rich because we do not care about fuel economy. batch firing is 1 ms faster than sequential firing. And newly derived system DI is using the best of twin inject system.

http://ask.cars.com/2008/08/types-of-fuel-i.html

Hyundai says its GDI system solves that issue by injecting gasoline directly into the combustion chamber at up to 2,175 PSI. The pistons are “domed” to increase combustion efficiency. Each injection consists of two pulses. The first pulse occurs during the intake stroke and the second at the end of the compression stroke, when the rest of the fuel is injected. http://autoshow.autotrader.ca/2010/08/13/2011-hyundai-sonata-2-0t/

http://www.picoauto.com/automotive-library.html

http://www.scribd.com/doc/7314297/electronic-multipoint-fuel-injection-system(this article is written by some engineering student, if I can contact him I will ask him the same question reagrding how does MPFI works batched and sequential)

i am working on this fuel injection kit. so I am going to the bottom of this. The kit also has batch firing MPFI system and the manual says it can work as sequential setup as well. Well I ll keep you updated. this is quite fascinating that if the injectors have physical address or something. Like we have in our computer where we install 2 drives on one IDE/sata slot.  

until then chao

hahah, I like the fact how you convey your idea making it sound rite as well as wrong. Smart guy.

Ne how as i mentioned that I will have some solid references to back up what I am saying, literture wise haven't found a positive book which explains about how does MPFI different then SEFI, all it states is MPFI can be Sequential/or batched. Now the question what is bothering me how is that possible, when we talk about sequential system we have driver for each injector(eg: 4 injectors means 4 drivers and so on) but in MPFI mostly I have examples here they say if its four cylinder engine mostly has 2 drivers to run 4 injectors(2 injectors per driver) but then how does the system runs in sequence. I am still doing my research.

But I am 200% sure and bet you any money they SEFI and MPFI is not the same. SEFI is derived from MPFI as batch firing is not required at low rpms, it vaporises fuel at low engine speed hence reduces efficiency. Hence the result SEFI is used more precise and accurate mixture every time.

For general public. SEFI is the best if u have the option. for better response and fuel economy.

For rohit .. i have a report by couple of engineering students who explain the benefits of MPFI and SEFI. Batch firing is must for high performance engines because at high horsepowers keeping the intake manifold wet keeps the air charge cold and rich because we do not care about fuel economy. batch firing is 1 ms faster than sequential firing. And newly derived system DI is using the best of twin inject system.

http://ask.cars.com/2008/08/types-of-fuel-i.html

Hyundai says its GDI system solves that issue by injecting gasoline directly into the combustion chamber at up to 2,175 PSI. The pistons are “domed” to increase combustion efficiency. Each injection consists of two pulses. The first pulse occurs during the intake stroke and the second at the end of the compression stroke, when the rest of the fuel is injected. http://autoshow.autotrader.ca/2010/08/13/2011-hyundai-sonata-2-0t/

http://www.picoauto.com/automotive-library.html

http://www.scribd.com/doc/7314297/electronic-multipoint-fuel-injection-system(this article is written by some engineering student, if I can contact him I will ask him the same question reagrding how does MPFI works batched and sequential)

i am working on this fuel injection kit. so I am going to the bottom of this. The kit also has batch firing MPFI system and the manual says it can work as sequential setup as well. Well I ll keep you updated. this is quite fascinating that if the injectors have physical address or something. Like we have in our computer where we install 2 drives on one IDE/sata slot.  

until then chao