Does Fuel Injection really give that much of an advantage?

Steeroid · 29th April 2006, 11:33

I am not sure if there has been a similar thread before - mods may consider merging them if there is a similar topic that I couldnt find.

Over the last few years we've seen the demise of carburettors in automobiles and the advent of fancy electronics and complex fuel injectors that cost twice more and are infinitely more difficult to repair.

Additionally, these injectors need an army of sensors at various points to be able to do their work properly, a job that carbs did without all those helpers hanging around.

At the end of the day, are we really better off with Fuel Injectors? I'm not a techie, but it does seem like we are NOT getting anything more in terms of FE or Power that Carbs couldnt give. It also means that we can no longer get our hands dirty and service our cars - it has to be taken to the Authorized Service Centre and plugged into a computer. It also means that your vehicle is very sensitive about fuel, dirty air and other variables that a carburettor would've brushed off.

It also means that tuning a car now costs you more - where a tuner could've fooled around with air-fuel mixtures manually (admittedly with less precise results as it depends on the quality of your tuner) you now have to buy a chip that costs you more than it would to give your car a full coat of paint.

The question for all of you then is whether we really are better off with Fuel Injection. I've been to countries before where older, carb-based vehicles have had a premium in the resale value simply for the 'no injector' fact.

I'm assuming the techies out here will be able to give a good reason why we are better off with FI - otherwise the manufacturers are taking us for a costly ride...

Rtech · 29th April 2006, 11:40

A good real world example to show the clear benefits of MPFI over carburettor is the Esteem. Carb. version produced about 62hp. With MPFI, it produces 85 with no drop in consumption (slightly better actually) and cleaner emissions as well.

So yes, I am a firm believer in Fuel Injection.

manson · 29th April 2006, 11:56

RT, did the carb esteem make 62 or 72 bhp?

manson.

RJK · 29th April 2006, 12:24

I thought carbed esteem was 65bhp.

adya33 · 29th April 2006, 12:24

Agree with RTech here.
Fuel injection helps in reducing emission without drop in power or FE. If anything it increases both.

Complaining about lack of playing with car getting hands may be true but for 90% of people that argument doesn't make any sense.

nitinhegde · 29th April 2006, 12:26

Here's some food for thought ..............

In trying to keep up with emissions and fuel efficiency laws, the fuel system used in modern cars has changed a lot over the years.

The Fall of the Carburetor !
For most of the existence of the internal combustion engine, the carburetor has been the device that supplied fuel to the engine. On many other machines, such as lawnmowers and chainsaws, it still is. But as the automobile evolved, the carburetor got more and more complicated trying to handle all of the operating requirements. For instance, to handle some of these tasks, carburetors had five different circuits:

Main circuit - Provides just enough fuel for fuel-efficient cruising

Idle circuit - Provides just enough fuel to keep the engine idling

Accelerator pump - Provides an extra burst of fuel when the accelerator pedal is first depressed, reducing hesitation before the engine speeds up

Power enrichment circuit - Provides extra fuel when the car is going up a hill or towing a trailer

Choke - Provides extra fuel when the engine is cold so that it will start

In order to meet stricter emissions requirements, catalytic converters were introduced. Very careful control of the air-to-fuel ratio was required for the catalytic converter to be effective. Oxygen sensors monitor the amount of oxygen in the exhaust, and the engine control unit (ECU) uses this information to adjust the air-to-fuel ratio in real-time. This is called closed loop control -- it was not feasible to achieve this control with carburetors. There was a brief period of electrically controlled carburetors before fuel injection systems took over, but these electrical carbs were even more complicated than the purely mechanical ones.

At first, carburetors were replaced with throttle body fuel injection systems (also known as single point or central fuel injection systems) that incorporated electrically controlled fuel-injector valves into the throttle body. These were almost a bolt-in replacement for the carburetor, so the automakers didn't have to make any drastic changes to their engine designs.

Gradually, as new engines were designed, throttle body fuel injection was replaced by multi-port fuel injection (also known as port, multi-point or sequential fuel injection). These systems have a fuel injector for each cylinder, usually located so that they spray right at the intake valve. These systems provide more accurate fuel metering and quicker response....

Note from the Team-BHP Support Staff : Do make sure that you provide the references/original source for every piece of material that has been taken from another website/publication, to give credit to the original author.

We advice you to read the Announcements and Board Rules section before proceeding any further.

I'm going to do you a favor and post the link below:
http://auto.howstuffworks.com/fuel-injection1.htm

Technocrat · 29th April 2006, 12:42

Quote:

Originally Posted by Steeroid

Additionally, these injectors need an army of sensors at various points to be able to do their work properly, a job that carbs did without all those helpers hanging around.

I disagree here, this is the biggest difference with FI engines, the service intervals for FI engine is much higher than the carbs one. also unlike the carbs which needs more monitoring more so when the car ages. A lot of our headaches have taken care by the engine management system. I remember every time we decided to head out of town we had to do a engine check, in the FI car you can just take the vehicle on highway without thinking, unless ofcourse it has some serious trouble.

And yes Rtech gave a good example & this has been the case with most of the Bikes as well (Not yet in India though).

So mee too with the FI

nitinbhag · 29th April 2006, 12:57

Quote:

Originally Posted by Steeroid

The question for all of you then is whether we really are better off with Fuel Injection. I've been to countries before where older, carb-based vehicles have had a premium in the resale value simply for the 'no injector' fact.

I would have said fuel injection is much better till around a month ago..

However, after my Siena has spent 4+ weeks in the garage (Sundaram & Bosch) and no solution other 'change ECU' in sight yet (and no spare ECU available), I am wishing that it was a carburated engine

Psycho · 29th April 2006, 19:49

Carbs good over a smaller rev range, FI great over the complete power band
Carbs easy to tune, FI need the electronics
Carbs need regular service, FI doesnt

jkdas · 29th April 2006, 19:57

My vote for ECUs: Maintenance free and more power. Less grease on one's hand when it needs to be tuned

Mpower · 29th April 2006, 22:01

Quote:

Originally Posted by Rtech

Carb. version produced about 62hp. With MPFI, it produces 85 with no drop in consumption.

RT, the power hike was due to the switch from 8 valves to 16 valves.(all Marutis) So far, Conti, Indica got only EFI with no power gain.

Also FI gives great control over the air fuel ratio.......which is needed for the cat-con to work properly. So its really emissions that is driving the change. Good FE is a bonus. nitin's post explains all the functions.

The next revolution will be when 2 wheelers switch to FE.

adya33 · 29th April 2006, 22:09

Quote:

Originally Posted by Mpower

RT, the power hike wasdue to the switch from 8 valves to 16 valves.(all Marutis) So far, Conti, Indica got only EFI with no power gain.

With introduction of MPFI Opel Astra went from 75BHP to 92BHP.
Though previously it was single point fuel injection and not carb.

veyron1 · 29th April 2006, 23:05

the best of both worlds; mechanical FI; lesser dependency on electronics, minimal sensors, better for tuning..

nitroxx · 29th April 2006, 23:07

Fuel injection ( chip remapping ) carbs ( floating check?), Forced Induction (F.I), Carbs? boost control ... Carbs? Greddy Emanage.... Carbs? High flow fuel pump ... Carbs? WTF?

nitroxx · 29th April 2006, 23:10

Veyron 1 .... Bugatti 1000 bhp ....Carbs? If knowledge is a treasure chest then the mind is the key to open.

View Poll Results: Is Fuel Injection really such a great boon?
Yes, we're much better off without carbs and mechanical induction.	39	90.70%
No, carbs were cheaper to own, maintain and tune and gave us similar power and FE.	4	9.30%
Voters: 43. You may not vote on this poll

29th April 2006, 11:33	#1
Steeroid Senior - BHPian Join Date: Mar 2005 Location: N.A Posts: 7,026 Thanked: 2,757 Times	Does Fuel Injection really give that much of an advantage? I am not sure if there has been a similar thread before - mods may consider merging them if there is a similar topic that I couldnt find. Over the last few years we've seen the demise of carburettors in automobiles and the advent of fancy electronics and complex fuel injectors that cost twice more and are infinitely more difficult to repair. Additionally, these injectors need an army of sensors at various points to be able to do their work properly, a job that carbs did without all those helpers hanging around. At the end of the day, are we really better off with Fuel Injectors? I'm not a techie, but it does seem like we are NOT getting anything more in terms of FE or Power that Carbs couldnt give. It also means that we can no longer get our hands dirty and service our cars - it has to be taken to the Authorized Service Centre and plugged into a computer. It also means that your vehicle is very sensitive about fuel, dirty air and other variables that a carburettor would've brushed off. It also means that tuning a car now costs you more - where a tuner could've fooled around with air-fuel mixtures manually (admittedly with less precise results as it depends on the quality of your tuner) you now have to buy a chip that costs you more than it would to give your car a full coat of paint. The question for all of you then is whether we really are better off with Fuel Injection. I've been to countries before where older, carb-based vehicles have had a premium in the resale value simply for the 'no injector' fact. I'm assuming the techies out here will be able to give a good reason why we are better off with FI - otherwise the manufacturers are taking us for a costly ride...
	() Thanks

29th April 2006, 11:40	#2
Rtech Team-BHP Support Join Date: Apr 2004 Location: Bombay Posts: 5,765 Thanked: 371 Times View My Garage	A good real world example to show the clear benefits of MPFI over carburettor is the Esteem. Carb. version produced about 62hp. With MPFI, it produces 85 with no drop in consumption (slightly better actually) and cleaner emissions as well. So yes, I am a firm believer in Fuel Injection.
	() Thanks

29th April 2006, 11:56	#3
manson Distinguished - BHPian Join Date: Oct 2004 Location: Bombay Posts: 3,933 Thanked: 4,290 Times View My Garage	RT, did the carb esteem make 62 or 72 bhp? manson.
	() Thanks

29th April 2006, 12:24	#4
RJK Senior - BHPian Join Date: Feb 2004 Location: Mumbai Posts: 1,161 Thanked: 762 Times	I thought carbed esteem was 65bhp.
	() Thanks

29th April 2006, 12:24	#5
adya33 Senior - BHPian Join Date: Apr 2005 Location: Pune Posts: 1,834 Thanked: 185 Times	Agree with RTech here. Fuel injection helps in reducing emission without drop in power or FE. If anything it increases both. Complaining about lack of playing with car getting hands may be true but for 90% of people that argument doesn't make any sense.
	() Thanks

29th April 2006, 12:26	#6
nitinhegde BHPian Join Date: Apr 2006 Location: ~ Posts: 242 Thanked: 91 Times	Fall of the Carburetor ........ Here's some food for thought .............. In trying to keep up with emissions and fuel efficiency laws, the fuel system used in modern cars has changed a lot over the years. The Fall of the Carburetor ! For most of the existence of the internal combustion engine, the carburetor has been the device that supplied fuel to the engine. On many other machines, such as lawnmowers and chainsaws, it still is. But as the automobile evolved, the carburetor got more and more complicated trying to handle all of the operating requirements. For instance, to handle some of these tasks, carburetors had five different circuits: Main circuit - Provides just enough fuel for fuel-efficient cruising Idle circuit - Provides just enough fuel to keep the engine idling Accelerator pump - Provides an extra burst of fuel when the accelerator pedal is first depressed, reducing hesitation before the engine speeds up Power enrichment circuit - Provides extra fuel when the car is going up a hill or towing a trailer Choke - Provides extra fuel when the engine is cold so that it will start In order to meet stricter emissions requirements, catalytic converters were introduced. Very careful control of the air-to-fuel ratio was required for the catalytic converter to be effective. Oxygen sensors monitor the amount of oxygen in the exhaust, and the engine control unit (ECU) uses this information to adjust the air-to-fuel ratio in real-time. This is called closed loop control -- it was not feasible to achieve this control with carburetors. There was a brief period of electrically controlled carburetors before fuel injection systems took over, but these electrical carbs were even more complicated than the purely mechanical ones. At first, carburetors were replaced with throttle body fuel injection systems (also known as single point or central fuel injection systems) that incorporated electrically controlled fuel-injector valves into the throttle body. These were almost a bolt-in replacement for the carburetor, so the automakers didn't have to make any drastic changes to their engine designs. Gradually, as new engines were designed, throttle body fuel injection was replaced by multi-port fuel injection (also known as port, multi-point or sequential fuel injection). These systems have a fuel injector for each cylinder, usually located so that they spray right at the intake valve. These systems provide more accurate fuel metering and quicker response.... Note from the Team-BHP Support Staff : Do make sure that you provide the references/original source for every piece of material that has been taken from another website/publication, to give credit to the original author. We advice you to read the Announcements and Board Rules section before proceeding any further. I'm going to do you a favor and post the link below: http://auto.howstuffworks.com/fuel-injection1.htm Last edited by Mpower : 1st May 2006 at 01:51.
	() Thanks

29th April 2006, 19:49	#9
Psycho Senior - BHPian Join Date: Jul 2004 Location: Bangalore Posts: 1,041 Thanked: 111 Times View My Garage	Carbs good over a smaller rev range, FI great over the complete power band Carbs easy to tune, FI need the electronics Carbs need regular service, FI doesnt
	() Thanks

29th April 2006, 19:57	#10
jkdas Senior - BHPian Join Date: Sep 2005 Location: Thiruvananthapu Posts: 9,687 Thanked: 1,496 Times View My Garage	My vote for ECUs: Maintenance free and more power. Less grease on one's hand when it needs to be tuned
	() Thanks

29th April 2006, 23:05	#13
veyron1 Senior - BHPian Join Date: Mar 2005 Location: Mumbai Posts: 1,424 Thanked: 54 Times View My Garage	the best of both worlds; mechanical FI; lesser dependency on electronics, minimal sensors, better for tuning..
	() Thanks

29th April 2006, 23:07	#14
nitroxx Awaiting Email Confirmation Join Date: Nov 2004 Location: DXB Posts: 815 Thanked: 31 Times View My Garage	Fuel injection ( chip remapping ) carbs ( floating check?), Forced Induction (F.I), Carbs? boost control ... Carbs? Greddy Emanage.... Carbs? High flow fuel pump ... Carbs? WTF?
	() Thanks

29th April 2006, 23:10	#15
nitroxx Awaiting Email Confirmation Join Date: Nov 2004 Location: DXB Posts: 815 Thanked: 31 Times View My Garage	Veyron 1 .... Bugatti 1000 bhp ....Carbs? If knowledge is a treasure chest then the mind is the key to open.
	() Thanks