Go Back   Team-BHP > BHP India > Commercial Vehicles


Reply
 
Thread Tools Search this Thread
Old 8th December 2016, 19:49   #31
BHPian
 
Join Date: May 2007
Location: kerala
Posts: 64
Thanked: 26 Times
Default Re: Daimler India launches Mercedes-Benz SHD 2436 coach

Quote:
Originally Posted by Rahul Rao View Post
.
A PTO sources it's energy from the gearbox, whenever the engine is declutched, it stops rotating, and as soon as the clutch is engaged again it starts rotating after this momentary stop and this start loads the entire chain from compressor, drive shaft to PTO to gearbox to clutch, and finally engine.
A belt driven system sources energy from crank pulley which is rotating continuously. Even when compresser cuts off after achieving set temperature, it restarts after a minimum of 3 to 5 minutes.

Rahul
PTO can be attached directly to the engine itself. Prime examples are transit mixers without separate engine. Most truck and bus engines have the provision.
In my opinion the manufactures must move towards inverter type compressors running by dc. It may increase the efficiency and reduce the complexity of belt drive and magnetic clutch.

Last edited by dracul : 8th December 2016 at 19:52. Reason: Add information
dracul is offline   (1) Thanks Reply With Quote
Old 9th December 2016, 09:52   #32
BHPian
 
Join Date: Dec 2013
Location: Pune
Posts: 579
Thanked: 587 Times
Default Re: Daimler India launches Mercedes-Benz SHD 2436 coach

Quote:
Originally Posted by dracul View Post
PTO can be attached directly to the engine itself. Prime examples are transit mixers without separate engine. Most truck and bus engines have the provision.
Good to know this, I will try to see this arangement.

Quote:
Originally Posted by dracul View Post
In my opinion the manufactures must move towards inverter type compressors running by dc. It may increase the efficiency and reduce the complexity of belt drive and magnetic clutch.
Inverter type is more effecient, and it will be effective in series hybrid buses, but for buses with conventional diesel and normal gearbox, or parallel hybrid it is converting mechanical energy to electrical and back to mechinacal with loss of effeciency in both conversions. Here use of variable stroke compressors to control capacity will be more effecient.

Rahul
Rahul Rao is offline   (1) Thanks Reply With Quote
Old 9th December 2016, 17:26   #33
Distinguished - BHPian
 
Ashley2's Avatar
 
Join Date: Oct 2009
Location: NH7
Posts: 2,085
Thanked: 1,430 Times
Default

Quote:
Originally Posted by Rahul Rao View Post
A PTO to drive a Ac compressor doesnt work, it has been tried before without success. A Ac compressor needs a high starting torque, and comparatively low running torque to keep it rotating. Once compressor cuts off, it needs about 2 Min for pressures on both sides to equalise. If restarted without equilising the needed torque will go up considerably.
If you see pressures on R 134a Ac system, while running the suction side is between 30 and 40 psi, while discharge side is between 180 and 250 psi. After equilising both sides have something between 90 to 120 psi depending on ambient temperature.
A PTO sources it's energy from the gearbox, whenever the engine is declutched, it stops rotating, and as soon as the clutch is engaged again it starts rotating after this momentary stop and this start loads the entire chain from compressor, drive shaft to PTO to gearbox to clutch, and finally engine.
A belt driven system sources energy from crank pulley which is rotating continuously. Even when compresser cuts off after achieving set temperature, it restarts after a minimum of 3 to 5 minutes.

Rahul
Rahul, I was referring PTO system only for engine cooling and not for AC. This is a common feature in all the modern day rear engine chassis like B11R, B13R and recently launched B8R.

Quote:
A PTO sources it's energy from the gearbox, whenever the engine is declutched, it stops rotating, and as soon as the clutch is engaged again it starts rotating after this momentary stop and this start loads the entire chain from compressor, drive shaft to PTO to gearbox to clutch, and finally engine
It doesn't stop rotating. It rotates constantly with the engine speed as its connected with idler shaft and its rotation is independent of clutch. Also I guess PTO driven AC compressors are used in Double Decker AC's

Last edited by aah78 : 13th December 2016 at 21:23. Reason: Posts merged.
Ashley2 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Scania launches Metrolink - New coach range for India Ashley2 Commercial Vehicles 51 25th August 2014 00:24
Volvo Launches B9R Coach : 9400 6x2 nevertouchme Commercial Vehicles 260 2nd March 2014 20:15
Mercedes Benz Buses now part of Daimler India Commercial Vehicles Redline6800 Commercial Vehicles 9 25th May 2013 06:19
Daimler Unveils Mercedes-Benz F-CELL Roadster With Hybrid Drive hanmust The International Automotive Scene 9 26th March 2009 21:18
Mercedes Benz / Daimler Chrysler change of Leadership! GTO The International Automotive Scene 0 29th July 2005 09:28


All times are GMT +5.5. The time now is 13:38.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks