[srijit]

Hi guys, I find myself in the position of having to explain the difference between older engines (before MPFI,CRDI,TDi,MJD,PD etc) and new engines to an elder person.

This person has somehat extensive knowledge of older engines, petrol and diesel, but does not understand how ECU and how modern engines differ from old ones.

I, have little knowledge of how both types work.
I'd appreciate links or pointers to where I can pickup the differences (possibly in a simple reading style).
An explanation of Turbo's would be the icing on the cake.

Thanks in advance for your efforts. cheers:

[aerohit]

You will have to read a book to understand as no one will here will be able to explain you. You will probabaly get contradicting information. Modern engines are way too advanced to be explained by some guy.

It is a good idea to go to manufacturers website and do your own research.

[androdev]

hmmm.. wiki and howstuffworks are fantastic sites but I am not sure about sites that focus on differences.

[srijit]

OK, I tried HowStuffWorks and that seems nice. I guess I am looking for info on how specifically the new engines differ from old ones. From my limited reading I can see differences are in things like ECU, fuel injection, carbs etc. I'd like to know what new item has replaced what old item in engines. I dont need much detail, just simple explanations should suffice

[kuttapan]

Carbs were replaced by Injection systems. ECU takes over the igntion control, so no more distributors, CB points etc. Lots of sensors come into picture, which were not there in older cars.

Regarding diesels, the challenge earlier was to increase the fuel pressure, which was dependent on engine rpm. But in common rails, they are able to maintain pressures of 1400-1600bar in the common rail, which aids better combustion, more power, more efficiency yada yada yada...Before, diesels had no electronics, but now they too have the ECU to control the injections, monitor sensors etc.

That was from a novice. Wait and see if the engine gurus are gonna help you further.

[Gautam Misra]

It will not be of much help but purely from a layman's point of view the new engines, especially the diesel ones, have become more fuel efficient and eco-friendly.There was a special stall in the auto expo which was held january 2008 in New Delhi which explained the finer aspects of the new generation diesel engines. May be you can search some of the archives.

[Rudra Sen]

Other side of this comparison here.

[Sankar]

Quoting text from the link Rudra posted.

Originally Posted by Times News Network

Newer cars spew more CO2 than old

CSE Analysis Says Vehicles Post-2005 Pollute More

TIMES NEWS NETWORK

New Delhi: In a complete reversal of international trends, new cars in India are spewing more greenhouse gasses than older models, pushing up emissions in Delhi alone by 72% in five years (2002-07), the Centre for Science and Environment said on Monday, releasing its analysis of emissions data accessed from the Automotive Research Association of India.

Emissions from two-wheelers in the same period, in comparison, have gone up by 61%, the analysis said.

For the consumer, this might be a pointer to deteriorating fuel efficiency of new cars as well — emissions of carbondioxide are closely linked to the fuel efficiency of vehicles.

The ARAI had clubbed data of vehicles of different periods that CSE accessed. The cars and two-wheelers had been classified into groups ranging from 1991-96, 1996-2000, post 2000 and post 2005.

The post 2000 petrol cars, with engine size more than 1,400 cc, emit 143 gm/km of CO2. In comparison, post 2005 models of same engine size emit 173 gm/km, CSE said. Extrapolating the emission statistics for fuel efficiency, CSE said the figures implied that fuel economy had dropped in these cars from 16 km/litre to 13 km/litre.

But Anumita Roychowdhury, of CSE’s Right to Clean Air Campaign, said, ‘‘This data is extrapolation... The ministry of surface transport has refused to share actual data.’’

Auto manufacturers share fuel economy data for car models at the time of certification of new vehicles with the government. ‘‘But the ministry withheld this information under the Right to Information Act, calling it of commercial importance and third party information. This data is routinely published in other countries to help consumers select fuel efficient vehicles and help governments set up fuel economy standards,’’ she added.

‘‘At a time when we are talking of an oil crisis, it is callous for the government and industry to not even share data on fuel efficiency with the public,” said Roychowdhury. SUVs worst polluters: CSE

New Delhi: Anumita Roychowdhury, of CSE’s Right to Clean Air Campaign, says: “Government and industry data on heat trapping CO 2 emissions that directly depend on the amount of fuel burnt, show oil guzzling vehicles are hitting road.”

A pointer to why the industry and ministry are fighting shy could lie in the figures CSE got out of ARAI. Diesel car models with engine size less than 1,600 cc and produced between 1996 and 2000, the NGO found, emit 129 gm/km but comparable post-2005 models emits 149 gm/km. Using similar mathematical models, it extrapolated that the fuel economy in this class had dropped from 20 km/litre to 18 km/litre.

SUVs, predictably, came out worst polluters. SUV models of 1996-2000 with engine size less than 3,000 cc emitted 189 gm/- km, while post-2000 models emitted 229 gm/km and post-2005 models emitted 256 gm/km. The fuel economy of SUVs had dropped from 14 km/litre in 1996-2000 models to 10 km/litre in post 2005 models: the guzzlers were consuming the equivalent of almost two small cars.

The increase in CO 2 emissions, CSE said, emerged out of type of technology used, unbridled growth in number of vehicles on road.

If this is true what could be the reason behind it? What i understand is since the internal combustion engine technology is improving and the fuel we are getting is better shouldn't the reverse of this be happening? I could see newer generation Diesels, compared to older Diesels, spewing thick black smoke when floored hard. But Petrol?!

[harsha.cs1]

I understand that gm/kg is just a shallow look at the issue. the report should also focus on the constituents of the pollutants. for instance Carbon Monoxide is sheer poison, whereas some other pollutants may not be that harmful. I am sure the report would have looked at those things, just that we have not read the whole report.

[srijit]

Thanks guys. Been reading a bit in HowStuffWorks and will try to post the parts that made sense to me

[shankar.balan]

I saw a detailed article on this same subject this morning in TOI Bangalore. States that vehicles especially SUVs produced after 2005 are really vicous in terms of pollution.
Would anyone on the forum who is in the know, please enlighten me whether this is really to be believed?
Because I m not able to understand how all this BS2 and BS3 compliance really helps, if this is actually the case.

[hrishig]

What happend to those Bharat 2 , 3 , 4 ..... norms. Aren't they suppose to control this ? We have seen manufactures adhering to those norms and making changes in engines. and ARAI certifying that cars are as per those norms.

So why is this happening?

[teknophobia]

One simple answer, the average sizes of the engines are getting bigger.

[GTO]

Originally Posted by teknophobia

One simple answer, the average sizes of the engines are getting bigger.

I'd disagree with your statement. The hatchback segment is being dominated by a 1.2 liter petrol range, primarily due to tax benefits. Plus, technology has made it possible to extract a useable 80 - 90 BHP out of a puny 1.2 liter petrol.

Within the hatchbacks & entry level sedans, the 1.3 L Fiat diesel engine is pretty much the most popular.

1.5 - 1.6 liter petrols dominate the C segment, same as a decade back. And the D segment stays at <2.4 L petrols.

Even if you look at MUVs, common-rail technology has made more power from a smaller capacity possible. Mahindra & Tata have both shifted to the awesome 2.2 engine (from 2.6 & 3.0 respectively).

The only segment where I'd say engine capacities have gone up is the uber-luxury sedan. The E280 & 530, for example, with their stonking 6 cylinder engines.

[teknophobia]

You've clarified my point yourself, from being dominated by 800 cc engines, the hatchback market is now being dominated by 1.2/1.3 l engines. Midsize sedan segment has gone up from 1.3 to 1.5/1.6 and there are far more D segment cars today. All adding up to an increased AVERAGE engine size for every segment.