[Sutripta]

Originally Posted by jalsa777

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I hope this satisfies your question

I have made it as simple and short as possible.
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Great, but something beyond I.C. Engines 100.5 would be really appreciated.

Originally Posted by Shan2nu

Can you post the technical details of this engine like cc, bore, stroke, comp ratio, peak power rpm, peak torque rpm.
Shan2nu

How big is your database? Why don't you post it? Others can then keep on adding to it.

Regards
Sutripta

[Shan2nu]

How big is your database? Why don't you post it? Others can then keep on adding to it.

None on this particular engine. So it would be interesting to see how it performed.

I just need data on the ones i've mentions.

Is this the same engine that does 15.5kgm@2000rpm?

Shan2nu

[D4D]

Firstly, Diesel's came into picture because of their torque. Being used for heavy applications, they always started with long strokes to make that torque. It's easier to attain a higher compression ratio in a under-square engine because of the long movement of the piston.

However, we don't necessarily need under-square engine for cars <1.5 tons.

There was one particular series of diesel engines from toyota that has either square or undersquare stroke ratio. Check this: http://en.wikipedia.org/wiki/Toyota_L_engine

[narendra.vw]

My knowledge , I like to say with my own technical words.

There are two type of bore stroke length in an engine(Stroke length & bore dia vary according to the designer) . 1. Short stroke 2. Long stroke.
Petrol engines had both short & long stroke. It is ignited by a spark.
Long stroke was used for torque to carry more load(eg. Amby)
Short stroke was used to increase rpm with respect to speed(eg. Old fiat).

Since diesel fuel is self ignited it needed long stroke.
Due to it’s torque, it was & is popular in heavy vehicles. Please note past generation engines were missing heater plugs.
As years passed technology improved, metallurgy improved, diesel engine became popular in cars for its torque. This is where Diesel short stroke engine was born. Since cars needed speed.
Since short stroke, fuel needed catalyst to ignite. Heater plugs were introduced. Later turbo was introduced to gain extra power by increasing the rpm (long stroke more torque, short stroke more speed).
Try having 4 adults in an diesel swift & drive through some hilly roads. Then you will know meaning of torque.

Doe to government’s change in rules & to cut cost cars manufacturer went for lesser CC engines.
Challenge was to have good power, less fuel intake, smooth run engines & of Corse good speeds.
This is where short stroke, TD, TDI crdi, inter coolers were introduced.
Small note, lesser CC engines has more Turbo lag then Higher CC engine.
The cooling system should be precise in design for short stroke engines.
Short stroke engines are very compact hence suitable for cars.
Generally engine’s life is less in short stroke .
Going deeper there is lot more to Know.

[Sutripta]

Originally Posted by narendra.vw

Please note past generation engines were missing heater plugs.
...
Since short stroke, fuel needed catalyst to ignite. Heater plugs were introduced.
...
The cooling system should be precise in design for short stroke engines.

Hi,
Could you please explain more about the heater plugs, catalyst, and the cooling system.

Regards
Sutripta

[narendra.vw]

Heater plug.
1.Old generation diesel engine had longer stroke length, meaning higher Compressed air before firing (Remember compressed air produces heat). Fuel spray was able to self ignite even in cold start. Partially In line fuel pump also helped. So, missing Heater plug.
For Old HCV, starter was on option. Small jerk would bring life to the engine (Cold or hot).

2. Once diesel engine was introduced in cars, short stroke (to increase rpm) & rotary type fuel pump
( to make fuel efficient & to reduce sound of Atomizer knocking), became the trend.
The compressed air heat in short stroke was not sufficient to self ignite while cold start.
It needed a catalyst to ignite. So, Heater plug was introduced.
Later, Electronics made engine Heater plug work according to engine Temp.
Hope, I have clarified in someway.

3. Cooling system, coming week.

[Sutripta]

^^^
Eager to hear about your views on the cooling system.

Must add that my understanding of need of heaters (and catalysts) is very different, and more mainstream.

Regards
Sutripta

[narendra.vw]

Before the next post, I like to know your views(Or the difference) of the previous topic. Helps in adding more details in my book. Thanks.
Regards, Narendra.

[Sutripta]

^^^
Minor quibbles aside,
A) Catalyst: In some very small HCCIs, the glow plug has a Platinum catalyst which actually initiates ignition. The heater plugs in our diesels are entirely different. No catalyst.

B) Need for heater: Has more to do with heat loss from combustion chamber than anything else. And that heavily depends on surface to volume ratios, and initial cylinder size/ volume. Thus necessary for IDIs (even with their very high (20+:1) CR). Helpful for small DIs. Not necessary for large DIs. Stroke does not really come into the picture.

Regards
Sutripta

[gthang]

Originally Posted by narendra.vw

It needed a catalyst to ignite. So, Heater plug was introduced.
Later, Electronics made engine Heater plug work according to engine Temp.

Thanks for the insight.

Looks like the words "Catalyst" and "Heater" have been misinterpreted by some.

Looking forward to your post on cooling systems.

Cheers

[narendra.vw]

Thanks, Mr. Sutripta for the reply
Thanks Mr. gthang for the clarification on my behalf.
Bit of Info.
1.Catalyst in Chemistry means, accelerate chemical reaction.
2. Present Mahindra ‘Pick up’ engine does not have heater plugs. Jeep used for load transport.

Cooling system.
Short stroke engine comparatively is lighter in all respect( eg: Head, Fly wheel).
A slightest tap on acc, rpm shoots up. Yes we are talking of more firing /minute.
To generate more power many parts were added to the engine( Turbo, Multiple valve/ cylinder which lead to multiple cams).
Basically we are talking of many moving parts. Lubricated or not still they give out heat. All these parts work at a very critical point. The oil supplied to all these parts should be kept as cool as possible. The cooling system’s circulation should be well designed to see that all these parts get desired viscosity of the Oil. Most TD engines have oil cooled by engine’s cooling system. Care should be taken not to have any air pocket in the cooling system.
To reduce weight aluminum alloy is used in many parts. Head is one of it.
These parts do not handle to many variation in heat. If Head is subjected to heat beyond it’s limit it bends. Same does not happen to cast Iron Head, first the gasket then the Head.
Lastly, better designed Radiator & Fan to complete better cooling system.

Some thing to think about,
The shortest stroke engine I have come across is ‘Formula I‘. We all know what kind of rpm it can reach.
If F1 car on track stays much longer behind a Safety car, engine heats up. That’s one of the reason cars sway around behind the Safety car to suck more cooling air.

By the way, anyone know to which engine‘s Radiator, the electrical cooling fan was introduced?

[Sutripta]

^^^
Your views on my views (on why heater plugs). Esp. specific disagreements.

Regards
Sutripta

[narendra.vw]

Let me make it clear for you once for all.
1. While in firing stroke, the Air is totally compressed to it’ max. Means it has produced heat as much as it can. A spray of fuel from atomizer should fire inside the chamber using compressed air & it’s heat.
There is no loss of heat in the combustion chamber unless there is back compression . This happens in weak engines.
2. When compressed air heat is not sufficient to fire the fuel the chamber is heated by heater plugs.
Must in cold start when compressed air heat is insufficient. Later engine heat takes care.
Volume & compression ratio depends on engine design.
As you said for larger engine heater plug is not necessary. They have long stroke.
Stroke really matters.

[gthang]

Originally Posted by narendra.vw

Cooling system.

Guess the overheating nature of shortstroke engines applies to both diesel and petrol?

I have noticed also a less variance in operating temperature in longstroke engines.

For e.g., my Harley, which has "Pepsi" can like pistons, when compared to the Ducati, which has "Nivea" can like pistons, runs at more or less the same temperature whether I ride hard or keep a steady pace. Both are ~1200cc.

The Ducati, however, runs noticeably cooler when ridden hard, and gets hot when ridden at a slow pace.

Please share your thoughts.

Cheers.

[Sutripta]

Originally Posted by narendra.vw

Let me make it clear for you once for all.
...

Hi,
You and I have very different (and as they say in divorce proceedings - irreconcilable) understanding on how an engine works. Lets leave it at that. Our posts can serve to tell readers that there are different opinions, and then leave it to them.

Regards
Sutripta