SMRT MAN Demostrator registered!
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I'm really digging the turbo whistle. I'm going to see if I can catch it today.
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Wow, the whistle from the two turbochargers sounds lovely!
A couple of clarifications if I may.
The engine is a D 2066 LUH with 6 horizontal cylinders, 4-valves per cylinder, exhaust gas recirculation, twin-stage turbocharging, and common rail injection. Peak power is 235kW (320 PS) @ 1900rpm and peak torque is 1600Nm @ 1000-1400rpm.
The gearbox would be the ZF-Ecolife 6 AP 1700B that has a maximum input torque of 1700Nm.
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Originally posted by SMB66X:
Curious on the other parts?
The granny seat can sit 2 pax?
Cheers.
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Does anyone know what time this bus leave woodlands int?
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the rear part of the MAN aisle looks rather narrow to accomodate more standing passengers as compared to the MB OC500LE buses. I still prefer having a step up along the aisle like the MB OC500LE rather than a fully low floor bus. Having experienced seating next to the aisle, I'd prefer the floor below the seat to be same level as the aisle, so that I can place my legs slightly outer to the aisle to balance myself whenever the bus turns.
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The bus is not in service as it may be under repairs.
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Originally posted by SGCar:
The granny seat can sit 2 pax?
Cheers.
meant for 1, tight squeeze if its for 2.
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twin-stage turbo is not same as twin turbo. rated power at 235kw@1900 rmp is not the continuous power n u will get at least 20% power loss from engine to ground
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Originally posted by SBS9818A:
meant for 1, tight squeeze if its for 2.
should be 2, cos i counted all the seats, and if the front seatings have to fit 2 ppl on each side, it will add up to the 38 seating arrangement. -
Originally posted by seyKai:
twin-stage turbo is not same as twin turbo. rated power at 235kw@1900 rmp is not the continuous power n u will get at least 20% power loss from engine to ground
Twin-stage turbocharging requires the use of two turbochargers. Basically you have two turbos of equal size, both installed in-line, with one boosting as per usual in the first stage, and the other (i.e. second stage) compounding the output from the first stage. This system must have been chosen because the required output boost pressure exceeded what could be produced by the use of a single turbocharger.
And yes, I know that NO internal combustion engine has a flat power/torque curve. It is physically IMPOSSIBLE. Also, I'm well aware of transmission losses (i.e. between flywheel and driving axle(s).
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Originally posted by SGCar:
The granny seat can sit 2 pax?
Cheers.
2 small size people or 1 big size people.
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the system is due the euro 5 emission standard n not power.
i would prefer inline vertical then horizontal engine due to wear n tear during power strokes
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Originally posted by seyKai:
the system is due the euro 5 emission standard n not power.
i would prefer inline vertical then horizontal engine due to wear n tear during power strokes
The system is required to meet power output requirements AND to improve emissions.
Engines without exhaust gas aftertreatment in the form of Selective Catalytic Reduction (e.g. in the case of the MAN D 20) often require quite significant de-tuning in order to comply with emissions regulations. This means that in order to comply with Euro 5 and EEV, a significant reduction of power and torque (specifically at the low end of the engine speed range) is required over and above what is required to meet Euro 2/3/4. A reduction of power and torque in the cruicial low engine speed range has a major impact on the driveability of a heavy vehicle such as a city bus so to counter this issue, engine manufacturers have improved fuel delivery systems and optimised turbocharging (e.g. by the use of variable geometry turbochargers or multi-turbo systems) so that in some cases, the final power and torque outputs are equal, if not higher than that of equivalent Euro 3/4 engines.
As for the use of engines with horizonal vs vertical cylinders, this is a matter of packaging constraints and operator demand. Horizontal engines have been used for decades in Europe, Australia, and elsewhere with extremely successful results with no compromises.
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EDIT: Slightly different than the way I expalined it above, but here's how MAN describes the twin-stage turbocharging process on their diesel engines:
As you can see, MAN have used two different sized turbos, one small and one large installed in-line (i.e. one downstream of the other). The concept is slightly different to the concept I had in mind, but the result is similar.
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egr engine runs on higher pressure n temp. the 2-stage turbo system is not a new technology and was modified to redirect some exhaust back to the cylinders to reduce emission n with ultra low sulpher diesel, the wear n tear to engine components is higher.
horizontal or vertical engine works the same except for higher maintenance
fleet managment would prefer higher output vs downtime n choosing the right equipment for the job is very important.
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Originally posted by seyKai:
egr engine runs on higher pressure n temp. the 2-stage turbo system is not a new technology and was modified to redirect some exhaust back to the cylinders to reduce emission n with ultra low sulpher diesel, the wear n tear to engine components is higher.
horizontal or vertical engine works the same except for higher maintenance
fleet managment would prefer higher output vs downtime n choosing the right equipment for the job is very important.
Is there a reason why horizontal engine requires higher maintenance than vertical engine? The same engine is installed just in a different position issnt it?
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most of the wear n tear in the cylinders are coz by the power strokes and in this case the cyl. r lying down with more load to 1 side
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Originally posted by seyKai:
horizontal or vertical engine works the same except for higher maintenance
Sorry, but I don't believe that for one minute.
Mercedes-Benz has been producing buses with engines with horizontal cylinders for who knows how long, and for the overwhelming majority of cases, these engines would be able to operate with basic maintenance for over 1,000,000 km under strenuous conditions without any work done to the engine block itself.
Staged and sequential turobhcarging concepts have been around for decades as well...
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Originally posted by Powered_By_CNG:
Sorry, but I don't believe that for one minute.
Mercedes-Benz has been producing buses with engines with horizontal cylinders for who knows how long, and for the overwhelming majority of cases, these engines would be able to operate with basic maintenance for over 1,000,000 km under strenuous conditions without any work done to the engine block itself.
Staged and sequential turobhcarging concepts have been around for decades as well...
the block is not the only main component in an engine, if no damage, u can use it yur whole life time or if u wan to double or trible the 1m km
the block itself has no moving parts so no wear n tear
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Originally posted by seyKai:
most of the wear n tear in the cylinders are coz by the power strokes and in this case the cyl. r lying down with more load to 1 side
Well, in that case only the cylinder lining will result in faster wear and tear. However, u might also be surprised to know that a cylinder lining cost only 5 to 30usd to replace it. That is pretty negligible considering the benefits that is gained (more space in the vehicle, lesser vibration caused)
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i just viewed the youtube video by sgbuses.
the whistle.
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Originally posted by XiaoTaro:
Well, in that case only the cylinder lining will result in faster wear and tear. However, u might also be surprised to know that a cylinder lining cost only 5 to 30usd to replace it. That is pretty negligible considering the benefits that is gained (more space in the vehicle, lesser vibration caused)
the cyl. liners will cost more than $30*6 n other parts needed to overhaul an engine + labour cost + downtime.u do get more space and lesser vibration so more comfort
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Is this bus on service today? I might want to catch both this and the Citaro later today.
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I'm going to go out and try catching this bus now.
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Bus not in service today. Asked the people at the control centre at Woodlands Interchange.