Originally posted by TIB429E:I remebered I came across a video showcasing that ZF Ecolife is much durable than Voith or something ? Is it true??
Well, here is a comparision video I found where ZF Ecolife is compared with Voith:
https://www.youtube.com/watch?v=4Z1vrmoYxeg
It says that ZF is quieter... But I believe ZF has more advantages than Voith.
Originally posted by SexyMichael:interesting to hear that, was expecting you to mention the Ecolife over the DIWA.
that mentioned, is the D20's lack of low-end torque an issue when it comes to drivability? based off observations, the local A22s dont seem to suffer that issue whilst the A24 demonstrator and to some extent the A95 show it.
also, would you propose a 6.2:1 rear axle ratio for future A95s?
Out of all the products, the MAN D20 engine is by far the best match for the Voith gearbosx that I have come across. Impeccably smooth changes up and down and great power delivery.
The D20 engine, which not having the same % of peak torque below 1000rpm as the Mercedes-Benz OM 457 or OM 470, is definitely no slouch. The slow initial takeaway that you are experiencing is a product of the gearbox electronically limiting the starting torque to improve ride quality and to reduce fuel consumption and output emissions. All modern gearboxes apply significant torque restriction in the lower gears, especially considering the peak torque output of today's engines.
Originally posted by PoweredByCNG:Out of all the products, the MAN D20 engine is by far the best match for the Voith gearbosx that I have come across. Impeccably smooth changes up and down and great power delivery.
The D20 engine, which not having the same % of peak torque below 1000rpm as the Mercedes-Benz OM 457 or OM 470, is definitely no slouch. The slow initial takeaway that you are experiencing is a product of the gearbox electronically limiting the starting torque to improve ride quality and to reduce fuel consumption and output emissions. All modern gearboxes apply significant torque restriction in the lower gears, especially considering the peak torque output of today's engines.
thanks for the clarifications.
onto transmissions and torque limitation, i understand that MAN and possibly Evobus have torque limiting features in their citybuses (ASR for MAN iirc) that prevent wheel skidding and hence ensure safety. however, this torque limiting aside, can I assume that a 360ps/1800Nm engine mated to a gearbox with 1600Nm max input torque will only have 1600Nm of effective torque (assuming no torque restriction by the gearbox is in place)?
i'm floating this question because MAN offers their NGxx3 articulated buses with the Ecolife 6AP2000B and DIWA 864.5 transmssions as options; suppose the above scenario does apply, what implications are there on the driveline and more specifically engine power/torque output?
On a secondary note, what are possible reasons for MAN mating the 6AP2000B with the D2066 LUH32 engine?
Originally posted by SexyMichael:thanks for the clarifications.
onto transmissions and torque limitation, i understand that MAN and possibly Evobus have torque limiting features in their citybuses (ASR for MAN iirc) that prevent wheel skidding and hence ensure safety. however, this torque limiting aside, can I assume that a 360ps/1800Nm engine mated to a gearbox with 1600Nm max input torque will only have 1600Nm of effective torque (assuming no torque restriction by the gearbox is in place)?
i'm floating this question because MAN offers their NGxx3 articulated buses with the Ecolife 6AP2000B and DIWA 864.5 transmssions as options; suppose the above scenario does apply, what implications are there on the driveline and more specifically engine power/torque output?
On a secondary note, what are possible reasons for MAN mating the 6AP2000B with the D2066 LUH32 engine?
Stability control is not the only reason why torque is restricted in lower gears. Even the heaviest city bus under the most strenuous conditions would never require the full services of an engine with 1800 Nm of peak torque. The Voith D864.5 can take an input torque of up to 1700 Nm but there's a good chance that the usable torque is 'capped' at a set value (e.g. up to 1500 Nm). The use of an engine in a higher state of tune would allow an even larger 'window' where actual peak torque is available. Because modern buses have systems communicating via CAN bus, it is possible for the gearbox, whose job it is to send power to the driving axle(s), to send a signal to the main 'brain' of the bus requesting limited torque. This is achieved either via electronic wastegate (to limit exhaust gases flowing through the turbocharger(s)) or via control of fuel injection.
Im in love with this decker,Hopefully SMRT will order more with tree guard of course
Originally posted by PoweredByCNG:Stability control is not the only reason why torque is restricted in lower gears. Even the heaviest city bus under the most strenuous conditions would never require the full services of an engine with 1800 Nm of peak torque. The Voith D864.5 can take an input torque of up to 1700 Nm but there's a good chance that the usable torque is 'capped' at a set value (e.g. up to 1500 Nm). The use of an engine in a higher state of tune would allow an even larger 'window' where actual peak torque is available. Because modern buses have systems communicating via CAN bus, it is possible for the gearbox, whose job it is to send power to the driving axle(s), to send a signal to the main 'brain' of the bus requesting limited torque. This is achieved either via electronic wastegate (to limit exhaust gases flowing through the turbocharger(s)) or via control of fuel injection.
what about the converse, where the transmission has a max torque input significantly higher than the engine's max torque?
Originally posted by PoweredByCNG:Stability control is not the only reason why torque is restricted in lower gears. Even the heaviest city bus under the most strenuous conditions would never require the full services of an engine with 1800 Nm of peak torque. The Voith D864.5 can take an input torque of up to 1700 Nm but there's a good chance that the usable torque is 'capped' at a set value (e.g. up to 1500 Nm). The use of an engine in a higher state of tune would allow an even larger 'window' where actual peak torque is available. Because modern buses have systems communicating via CAN bus, it is possible for the gearbox, whose job it is to send power to the driving axle(s), to send a signal to the main 'brain' of the bus requesting limited torque. This is achieved either via electronic wastegate (to limit exhaust gases flowing through the turbocharger(s)) or via control of fuel injection.
I think what he means is the configuration of MAN D2066 LUH32 (with a max torque of 1600Nm) mated to the gearbox ZF Ecolife 6AP2000B (with input torque of 2000Nm) which is strange.
Any ideas of why would this configuration be used instead of using the 6AP1700B which has a much closer input torque range?
Originally posted by Bus Stopping:I think what he means is the configuration of MAN D2066 LUH32 (with a max torque of 1600Nm) mated to the gearbox ZF Ecolife 6AP2000B (with input torque of 2000Nm) which is strange.
Any ideas of why would this configuration be used instead of using the 6AP1700B which has a much closer input torque range?
There's absolutely no problems with using a gearbox that has a higher torque input maximum. If anything, the gearbox will last longer this way as it is put under less stress than it was intended for.
Originally posted by SMB128B:Very good
I feel sorry that SBST's progress efforts still remain comparatively stagnant.
Hope they wake up and order more KUDs.
Originally posted by PoweredByCNG:Stability control is not the only reason why torque is restricted in lower gears. Even the heaviest city bus under the most strenuous conditions would never require the full services of an engine with 1800 Nm of peak torque. The Voith D864.5 can take an input torque of up to 1700 Nm but there's a good chance that the usable torque is 'capped' at a set value (e.g. up to 1500 Nm). The use of an engine in a higher state of tune would allow an even larger 'window' where actual peak torque is available. Because modern buses have systems communicating via CAN bus, it is possible for the gearbox, whose job it is to send power to the driving axle(s), to send a signal to the main 'brain' of the bus requesting limited torque. This is achieved either via electronic wastegate (to limit exhaust gases flowing through the turbocharger(s)) or via control of fuel injection.
What's with bus manufacturers preferring Voith's 4-speed over the 5-speed? Voith's website says it produces 5-speed transmissions too. The Transperth B7Rs and the SBS WEGs use the 4-speed, but I think the 5-speed may be better. In fact, I would like them mated with the KUB engine.
Originally posted by iveco:What's with bus manufacturers preferring Voith's 4-speed over the 5-speed? Voith's website says it produces 5-speed transmissions too. The Transperth B7Rs and the SBS WEGs use the 4-speed, but I think the 5-speed may be better. In fact, I would like them mated with the KUB engine.
Correct me if im wrong,Voith change gear slower than ZF thus for our city usage 4 speed seem to be enough
Originally posted by carbikebus:Correct me if im wrong,Voith change gear slower than ZF thus for our city usage 4 speed seem to be enough
Not really though, if you had taken 960 Voith Habit like 1040K, it accelerates faster than ZFs Habit...
I mean the gear change not power of accelerations
Originally posted by iveco:What's with bus manufacturers preferring Voith's 4-speed over the 5-speed? Voith's website says it produces 5-speed transmissions too. The Transperth B7Rs and the SBS WEGs use the 4-speed, but I think the 5-speed may be better. In fact, I would like them mated with the KUB engine.
Voith does not make a 5-speed automatic gearbox for buses. Scania does not offer their products with a Voith.
Originally posted by carbikebus:Correct me if im wrong,Voith change gear slower than ZF thus for our city usage 4 speed seem to be enough
It's a different concept. Read up on the differential wandler concept that Voith's DIWA range uses. It's very different to a conventional torque converter design.
Also, because of the wider spacing of gear ratios, it is not possible for a Voith gearbox to shift at the same engine speeds as a ZF-EcoLife without labouring the engine.
Thanks Dave!
Originally posted by Powered_By_CNG:Voith does not make a 5-speed automatic gearbox for buses. Scania does not offer their products with a Voith.
In the old days, Volvos came with ZF (Mk IIs, VO3Xes) and Scanias came with Voiths (CRBs).
Waiting for Mercedes Benz to produce a three axles Citaro DD with OM470 engine specially for Asian market
Waiting for SMRT to place order... I am sure 5888H trial is successful.
Originally posted by BusAnalayzer:Waiting for SMRT to place order... I am sure 5888H trial is successful.
yup if they are fine with E500 A95 is like 5 times better... hope after this they dont buy E500 anymore.
Hopefully Enviro500s orders stuck at 201 & SMRT/LTA add in 200 A95s
Currently, 91 E500 have been registered, almost half of 201 within half a year... Probably by end of June 2015, all 201 will be here...
Originally posted by Powered_By_CNG:It's a different concept. Read up on the differential wandler concept that Voith's DIWA range uses. It's very different to a conventional torque converter design.
Also, because of the wider spacing of gear ratios, it is not possible for a Voith gearbox to shift at the same engine speeds as a ZF-EcoLife without labouring the engine.
to answer the OP, the Voith DIWA Concept merges the torque converter with the retarder into a single unit, hence DIWA (DI -> Differential, that is torque converter; WA -> Wandler, that is retarder). simply put, the Voith torque converter functions BOTH as a torque converter and retarder under startoff and braking respectively, and this design philosophy/implementation underpins the vast difference in acceleration and braking characteristics between the ZF and Voith transmissions.
could PoweredByCNG explicitly justify the above claim with the specific gear ratios?
Originally posted by carbikebus:Hopefully Enviro500s orders stuck at 201 & SMRT/LTA add in 200 A95s
i would rather have them order E500s. gemilang bodied buses suck donkey shit! look at the a22s, bodywork dents and punches everywhere, weak, crap and cheap pussyfooting bodywork. smrt will not want to spend time fixing bodywork all the time. even now they are not fixing damaged bodywork. i rarely see citaro or b9tl bodywork that is as damaged and fragile as gemilang. if only the a95 came in a higher quality bodywork instead of the debatable gemilang bodywork, even if it may cost more but savings are made by not requiring repairs to lame damage.
Originally posted by TIB868X:i would rather have them order E500s. gemilang bodied buses suck donkey shit! look at the a22s, bodywork dents and punches everywhere, weak, crap and cheap pussyfooting bodywork. smrt will not want to spend time fixing bodywork all the time. even now they are not fixing damaged bodywork. i rarely see citaro or b9tl bodywork that is as damaged and fragile as gemilang. if only the a95 came in a higher quality bodywork instead of the debatable gemilang bodywork, even if it may cost more but savings are made by not requiring repairs to lame damage.
Looks I'm not the only one who prefers the Enviros over the MAN A95... The MAN A22s are easily cui and have spoilt parts, probably why I am not interested in the MAN A95. I find the Enviro is actually very comfy to take, while the MAN A22 is jerky... Another reason I think the MAN A95 is not as comfy.