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Old 11th February 2010, 22:57   #31
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Originally Posted by akash_m View Post
  • How does natural air help in cooling the air cooled engine of the bus (opposed to air entring from front grill in usual buses)
As you can see, there will be only forced cooling fron fan and radiator.There are less chances that engine will be cooled by natural flow of air.
This is one limitation on RE buses as this requires a better cooling system compared to FE buses
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Old 15th February 2010, 21:35   #32
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Well can't they place those radiators at front via hoses ? In this way engine can be naturally cooled .
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Old 16th February 2010, 11:40   #33
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Well can't they place those radiators at front via hoses ? In this way engine can be naturally cooled .
Well in few of the sports cars, this is the case but then their length is small and the piping is not that much. Imagine the lenght of piping and its associated disadvantages in your case??
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Old 16th February 2010, 18:10   #34
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Imagine the lenght of piping and its associated disadvantages in your case??
Then why not on the roof? With a scoop
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Old 17th February 2010, 09:38   #35
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Then why not on the roof? With a scoop
Why not on the sides! Like Lamborghini Murcielago!
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Old 19th February 2010, 15:18   #36
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AL back engine SLF. This bus ran in south mumbai and i still running any one has any idea abt the specs of it. Pls check the pic.
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Old 19th February 2010, 18:38   #37
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Originally Posted by EFF-EIGHT-BEE View Post
Well can't they place those radiators at front via hoses ? In this way engine can be naturally cooled .
1.By the way even if they are placed in front its called only Forced cooled only as Natural Cooling is something Tobe done with out radiators and by using only air - like in your bikes and other two wheelers.
2.By placing the radiators upfront one of the purpose of Rear engine buses - Low floor, will be defected.
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Old 14th March 2010, 01:29   #38
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Originally Posted by Spitfire View Post
Then why not on the roof? With a scoop
Because the buses are not very aerodynamic, there wont be adequate air flow on the roof for forced cooling.Also if mounted on the roof, it would have to be vertically mounted rather than horizontal or flat.Its the surface area that cools the engine jacket water.
Scoops are normally used for air intake in most cases, for the combustion process and not for cooling.

Trapezio- On murcielago, these air intakes provide air to the oil radiators, combustion(auto adjusted depending on the speed of the vehicle), general air flow in the engine compartment and the once on the bumper are for the high performance disc brakes.
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Old 14th March 2010, 22:03   #39
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Moreover, there are reliability issues (to be precise, large no. of issues) associated with the rear engined buses apart from the high life cycle costs. That could be the reason, why our home grown manufacturers are still laking a good competitor for the VOLVOs & BENZs. Adding to that the volumes offered in the RE bus market may not be economical (barring the DTC jnnurm orders for AL & TML)for the Indian manufacturers with mass production lines compared to that of VOLVO (capacity of 5 - 10 buses a day, correct me if I'm wrong)
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Old 14th March 2010, 23:55   #40
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(capacity of 5 - 10 buses a day, correct me if I'm wrong)
That's too much for a day, its for a week.
Their highest ever sales recorded will be around 600 for this year. Thanks for the JNnurm orders.
Last year it was less than 500.
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Old 15th March 2010, 00:27   #41
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Quote:
Originally Posted by Ashley2 View Post
2.By placing the radiators upfront one of the purpose of Rear engine buses - Low floor, will be defected.
I'm sorry I didn't get you there.Could you please elaborate? Are you talking about busted hoses because of the low ground clearance or a space crunch?
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Old 15th March 2010, 00:40   #42
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^^^!
normally in rear engined buses everything including propshaft, etc are at the back.

hence the bottom is made completely flat, so the below part is used as luggage compartment, etc. and hence the bed is low as possible

BTW radiator can be kept at front. As gear linkage does go upfront don't they.

But it will definitely use approx 10-15 liter extra coolant, depending upon pipe length. Not to forget they will have intercooler too. and maintaining that long pipes along with different L or U joints would be a headache.
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Old 15th March 2010, 19:22   #43
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Quote:
Originally Posted by AyAn! View Post
I'm sorry I didn't get you there.Could you please elaborate? Are you talking about busted hoses because of the low ground clearance or a space crunch?
As we know RE buses offer excellent sallon space, the only reason because the complete power train is packaged behind the rear axle. This also includes your radiator,Intercooler, Air intake pipe etc. Say for instance the radiator is placed upfront. Then the front portion - just near to windshield of the bus should be little higher to accomodate them. The lowest possible ground height for the RE bus so far configured is 390mm and with further 60mm kneeling option we can bring down upto 330mm. And definitely this is not possible with radiators in front - since chasis height should be raised for them to prevent getting damaged and also eats up space.
Next is as I have told earlier, either its placed front or behind its a forced circulation only and does not add much differance rather making things complicated with coolant pipes running through the length of bus and also adding unwanted cost.

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Old 15th March 2010, 21:56   #44
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RE AC buses can be a pain at times .These buses have a door on the floor around the last rows of seats ...probably to access the engine.

I had been in a B7R in which this door wasnt closed properly...and with no proper ventilation ...one could smell the exhaust fumes

As compared to a FE bus ,a RE RWD bus doesnt need the shaft to transfer drive unlike a front engined bus ..as a result ...you have a bigger luggage bay and lesser vibrations along with a lower floor
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Old 15th March 2010, 22:24   #45
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I have seen some RE buses with side mounted radiators
Quote:
Originally Posted by SirAlec View Post
But it will definitely use approx 10-15 liter extra coolant, depending upon pipe length. Not to forget they will have intercooler too. and maintaining that long pipes along with different L or U joints would be a headache.
You also need a much larger water pump that will rob hp.

Quote:
Originally Posted by speedsatya View Post
I had been in a B7R in which this door wasnt closed properly...and with no proper ventilation ...one could smell the exhaust fumes
Not sure about diesel, but petrol fumes can be fatal. Many people have died in garages with car running.
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