What makes a noisy bus ? How to get a quiet bus ??
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30 years ago, was mainly the noisy engines & lousy 3rd party bodies.
Nowadays, 3rd party bodywork have improved in quality but still tend to be a major source of noise irritation, i'll say. Modern engines are much quieter BUT certain types of gearbox & air-con compressors are simply too noisy !!!!
Worse, some use very noisy radiator air intake fans where the fan makes as much if not more noise than anything else on such a bus !
My equation for a quiet bus thus is :
Quiet bus = quiet engine + quiet gearbox + quiet air-con compressor, mainly these factors.
Other helpful features would be full engine & gearbox noise encapsulation, good quality bodywork with no 'loose ends' which squeak, crackle or rattle ! Also quiet air-con blower unit in the interior !
Therefore, optimal matching of these components upon bus purchase would certainly go a very long way towards ensuring the ultimate possible level of quietness, an extremely important component of pasenger comfort !!
I notice that on a bus with quiet engine, the noisest component is some 'ill matched' air-con compressor. Next down the line is some 'ill matched' gearbox.
Much effort can be put in to develop a most quiet engine BUT the passenger may not be able to take notice hence appreciate it much if the quietness is 'spoilt' simply by ill matching with noisy (often non original !!) key components.
For maximum passenger comfort, bus operators are well advised to take note & ensure that the original bus chassi maker 'endorsed' components are always used & to evaluate throughly with high priority on quietness any other component, assuming they already have a bus with quiet engine. -
You mean like VSO. Noisy voith, noisy condenser? Not to mention ear-splitting bell.
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Easy. Double glazed windows, sound deadening material in the panels. Use Denso air-conditioning... there is nothing like a low pitched hum of a Denso. Also, if you don't want noise, don't have hub reduction or a hypoid rear axle. Have an automatic gearbox, since they won't be noisy. Don't have an exhaust brake. Etc.
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What i hate most about these models are the extremely noisy radiator air-intake fans they use either in front or on the right side ! The engine itself i believe is quite quiet. Of course the noisy air-con machinary behind next in irritation !! As such the noisy gearbox don't seem so obvious here, probably 'drown' out !
On those 1.5 deckers i've riden on via PlusLiner from KL to SGP, i observe they
also use tranverse engine layout with the air-con machinary piled on top of the engine. But the engine, air-con & gearbox ALL were on the quiet side of things, even @ 100+ km/h speeds on the highway. Scania L94 i believe does NOT use those stupid noisy radiator air-intake fans like Leyland or Volvo, however !
SBST should perhaps sent an investigation team to explore why other's are so much quieter than theirs !Originally posted by SBS1908B:You mean like VSO. Noisy voith, noisy condenser? Not to mention ear-splitting bell. -
Noisy radiator fan on the right side of the VSO. but it's nice seeing leaves being blown away by the fan, like the O.405G's.Originally posted by SBS1908B:You mean like VSO. Noisy voith, noisy condenser? Not to mention ear-splitting bell.
the later VO's also have loud radiators at the front too.
the Voith gearbox only contributes in tis aspect by holding the engine and hence the radiator fan at higher rpm's for a longer time. -
Simple solution to the loud fans on the VSOs... put a match to them and *BOOOM!!!!*
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Most of the noisy buses I know of are front-engined, like the B57, OF1417 and Hino AK. Not forgetting the Bedford school buses.
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the scania l94Ub is (was?) reknown for its quietness. i tried taking SBS2888T on 518 in march 2003. damn quiet when idleing.
nowadays i hear its not as good as when in 2003 or before.
the hippo tours scania L94Ub are not so quiet as the air-con is very noisy. but outside u can hardly hear its engine when it goes by
ZYX -
yes. i liked it particularly for its ZF, powerful low-bass engine and the turbocharger whistling its way when the bus was speeding on tampines ave 10 & pie, if u sit at the rear inside the bus. Lance-like, but much smoother.Originally posted by ZYX2005:the scania l94Ub is (was?) reknown for its quietness. i tried taking SBS2888T on 518 in march 2003. damn quiet when idleing.
nowadays i hear its not as good as when in 2003 or before.
the hippo tours scania L94Ub are not so quiet as the air-con is very noisy. but outside u can hardly hear its engine when it goes by
ZYX -
But on O 405 G, they don't use those loud sounding 'remote link-up' type of fans as on the Olympians. So what you hear from the engine of the O 405 G is largely the 'real' engine sound, not mainly noisy fan sound !!
That's why the O 405 G's interior (likely exterior also) engine noise levels upon even hard acceleration is quieter than the Olympian's (with their type of fan noise included) since their engines obviously don't work without those fans.Originally posted by ^tamago^:Noisy radiator fan on the right side of the VSO. but it's nice seeing leaves being blown away by the fan, like the O.405G's.
the later VO's also have loud radiators at the front too.
the Voith gearbox only contributes in tis aspect by holding the engine and hence the radiator fan at higher rpm's for a longer time. -
VSO's are not noisy , i find the radiator not as loud the first time they were released on the roads . I really enjoy the sound of the acceleration and it's a very comfortable bus to ride on.
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Then maybe since then they addressed that issue on some units.
But on all the units i've riden, it remains unacceptably noisy to me, with such fan noise the main irritant. Even hearing from some distance away outside, i hear more of loud fan noise than 'real' engine noise upon acceleration, which makes the entire vehicle unneccessarily noisy to me.
When i consider noisy or quiet, i'm comparing 'across the board' with the quietest buses/coaches i've personally experienced & i don't tend to serparate PSV's into citybuses (which tend to be the noisier lot on the whole) & coaches, which have given me ultimately the quieter rides.
Suspension ride comfort has been improved on the latest Olympians, even from the upper deck. But i'll still don't find it the best in this area. As for enjoying the sound of the acceleration, i find the deaf-silence nature of the V-type engined buses far superior simply in that one hardly senses the presence of the engine (or any other sound) even as the vehicle's quickly & forcibly accelerating !Originally posted by Airbus330Captain:VSO's are not noisy , i find the radiator not as loud the first time they were released on the roads . I really enjoy the sound of the acceleration and it's a very comfortable bus to ride on. -
Try to put those buses on everyday revenue services and then you will knowOriginally posted by hseochin:What i hate most about these models are the extremely noisy radiator air-intake fans they use either in front or on the right side ! The engine itself i believe is quite quiet. Of course the noisy air-con machinary behind next in irritation !! As such the noisy gearbox don't seem so obvious here, probably 'drown' out !
On those 1.5 deckers i've riden on via PlusLiner from KL to SGP, i observe they
also use tranverse engine layout with the air-con machinary piled on top of the engine. But the engine, air-con & gearbox ALL were on the quiet side of things, even @ 100+ km/h speeds on the highway. Scania L94 i believe does NOT use those stupid noisy radiator air-intake fans like Leyland or Volvo, however !
SBST should perhaps sent an investigation team to explore why other's are so much quieter than theirs !
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I find some MK3 quite noisy when they brake. Very irritating.
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So ur saying that this is causd by wear and tear? another factor is maintenance... theirs are far betterOriginally posted by carbikebus:Try to put those buses on everyday revenue services and then you will know 
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I do believe those long distance coaches are subject to overall more demanding & stressful operating envirnoment than citybuses.
Like citybuses, both are very well used with little down time.
But in the case of coaches, these are driven mainly on highways for many hours non-stop @ maximum engine speed so temperature & all manner of mechanical stresses are taken to the extreme. Not surprising brakes too have to work much harder to slow down & stop a coach which normally runs @ 2 to 3 times faster than a citybus in slow city stop-start (i.e. more opportunties for the vehicle to 'rest') traffic !!Originally posted by carbikebus:Try to put those buses on everyday revenue services and then you will know -
On maintenence, based on the condition of the buses i've riden on, i find e.g. Handal Indah's buses better maintained than SJE's !Originally posted by SBS9828X:So ur saying that this is causd by wear and tear? another factor is maintenance... theirs are far better
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I feel that citybuses are more prone to wear and tear compared to express buses. That's because citybuses are subject to frequent acceleration and braking due to stop/go traffic conditions. The lower gears puts the most stress on the engine because that's when it will rev the highest. Gearbox are also subject to a higher wear rate due to the constant shifting of gears.Originally posted by hseochin:I do believe those long distance coaches are subject to overall more demanding & stressful operating envirnoment than citybuses.
Like citybuses, both are very well used with little down time.
But in the case of coaches, these are driven mainly on highways for many hours non-stop @ maximum engine speed so temperature & all manner of mechanical stresses are taken to the extreme. Not surprising brakes too have to work much harder to slow down & stop a coach which normally runs @ 2 to 3 times faster than a citybus in slow city stop-start (i.e. more opportunties for the vehicle to 'rest') traffic !!
Express buses, although twice as fast as citybuses, are actually cruising on the overdrive. They don't really push the engine to the limit but holds it at mid-range to get the best fuel consumption without compromising on torque and power. As for braking, unless you're reaching a toll booth or there's obstruction ahead, a slight jab on the pedal is sufficient. -
Yeah i also agree that citybuses are subject to more tear and wear bcoz of the frequent acceleration, braking and sometimes at the mercy of some ruthless drivers who treat the buses like rally cars. Furthermore, some of these citybuses serve high density routes and therefore commonly operates with full pax load, straining the suspension.
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On the brakes, in the case of citybuses, due to the lower driving speeds, the 'actual' brake pads get used more frequently, i'll say. Compared to outstation coaches where due to the higher driving speeds, more braking tends to be done via retarder or exhaust brakes (if used) & the 'actual' brakes are used only when a low enough speed is reached, before coming to a standstill.
So on brakes, i'll agree the 'actual' wear on the brakes on citybuses can be greater than on outstation coaches.
The various gears in the automatic gearbox for citybuses can also be used more often compared to the gears in a manual gearbox for outstation coaches, where the highest road speed gear tends to be used most of the time.
In both cases, wear on the gearbox can be very high only that its distributed differently. A case of possibly lower wear on each gear but with more gears being subjected to roughly the same level of wear for citybuses versus a case of very extremely higher levels of wear on the top road speed gear with far less wear on the other gears in the same gearbox for highway coaches. Ultimately which ever the case, the gearbox would still require sufficient frequent maintenance. 1 (especially important often used) gear fails even if the other gears are hardly used, the 'productivity' of the vehicle becomes noticibly worsened, which is definitely not acceptable !
Regarding engine operating speeds, i notice the automatic gearbox is programed such that the engine rarely touches & stays for any noticble time @ the maximum speed level. Majority of the time gear changes take place well within the green zone, so the engine doesn't really need to be exerted much to move the bus along. Road speeds are much lower [compared to the outstation highway coaches] implying actual levels of power & torque transmission through the engine, gearbox etc. tend to be much lower than the maximum designed to be handled.
The situation you mentioned below does not happen too often, as (from currently available coaches in use in Malaysia) i observe if you stay in the middle of the greenzone, your (level) road speed only ~ 60 to 80 km/h, too unproductively slow to be maintained for long stretches on the highway ! In order to be twice as fast as citybuses (assume these @ 60 km/h only) the outstation coaches would go @ 120 km/h, which i find quite a normal speed which can be maintained for quite some time on the N-S highway & that's in fact the sort of speeds actually used often from all my trips over the years. So @ 120 km/h, the engine speed is ~ 2500 rpm which is where the red zone starts !! In reality, this is the sort of engine speeds used much (almost all !) of the time on the outstation highway coaches.
The drivers simply want to extract the maximum possible performance from the coach & to appear as productively efficient as possible (to their passengers) so they tend to drive as fast as the driving envirnoment can allow. So this green zone i'll say is rarely observed & mostly it's touching well into the red zone !!
Yet the coaches somehow can withstand such levels of wear, which is definitely very much higher than on citybuses & even seems like 'chickenfeed' in comparison !
In summary i'll say that in the area of brakes, those on citybuses tend to be used much more than on outstation highway coaches while in engine operating speeds hence engine wear/stress levels, the engines on coaches are the ones used much more 'fully', being pushed literally to the end of the line whether on the speedometer or tachometer, which is hardly so in citybuses ! Gearbox wear high in both cases but the high speed stress to the gears on coaches can be worse than merely high use (but lower speed) stress on citybuses.
So from these factors alone, my deduction is that citybuses are subject to less overall stress hence less overall wear & tear than on outstation highway coaches. If the coaches were driven @ citybus levels of speed mostly, then the citybus would be the ones more subject to wear & tear i'll think.Originally posted by The_Bus_Guide:I feel that citybuses are more prone to wear and tear compared to express buses. That's because citybuses are subject to frequent acceleration and braking due to stop/go traffic conditions. The lower gears puts the most stress on the engine because that's when it will rev the highest. Gearbox are also subject to a higher wear rate due to the constant shifting of gears.
Express buses, although twice as fast as citybuses, are actually cruising on the overdrive. They don't really push the engine to the limit but holds it at mid-range to get the best fuel consumption without compromising on torque and power. As for braking, unless you're reaching a toll booth or there's obstruction ahead, a slight jab on the pedal is sufficient. -
Couldn't agree with you more,My Uncle is a full-time Coach driver with 17years of driving bus experience.He also emphasized that Citybuses are more prone to wear n tear than most Coaches/Express buses.Period.Originally posted by The_Bus_Guide:I feel that citybuses are more prone to wear and tear compared to express buses. That's because citybuses are subject to frequent acceleration and braking due to stop/go traffic conditions. The lower gears puts the most stress on the engine because that's when it will rev the highest. Gearbox are also subject to a higher wear rate due to the constant shifting of gears.
Express buses, although twice as fast as citybuses, are actually cruising on the overdrive. They don't really push the engine to the limit but holds it at mid-range to get the best fuel consumption without compromising on torque and power. As for braking, unless you're reaching a toll booth or there's obstruction ahead, a slight jab on the pedal is sufficient. -
Buses travelling at 120 km/h is OK but engine reaching 2500 rpm is not OK. The maximum power for even the best buses flats out at 2000 rpm (the actual start of the red zone). You can tweak the gear settings such that the bus is able to reach 120 km/h but I doubt that the engine will be revving until 2000 rpm, whatmore 2500 rpm. Its too dangerous, hardly ideal at all.Originally posted by hseochin:Regarding engine operating speeds, i notice the automatic gearbox is programed such that the engine rarely touches & stays for any noticble time @ the maximum speed level. Majority of the time gear changes take place well within the green zone, so the engine doesn't really need to be exerted much to move the bus along. Road speeds are much lower [compared to the outstation highway coaches] implying actual levels of power & torque transmission through the engine, gearbox etc. tend to be much lower than the maximum designed to be handled.
The situation you mentioned below does not happen too often, as (from currently available coaches in use in Malaysia) i observe if you stay in the middle of the greenzone, your (level) road speed only ~ 60 to 80 km/h, too unproductively slow to be maintained for long stretches on the highway ! In order to be twice as fast as citybuses (assume these @ 60 km/h only) the outstation coaches would go @ 120 km/h, which i find quite a normal speed which can be maintained for quite some time on the N-S highway & that's in fact the sort of speeds actually used often from all my trips over the years. So @ 120 km/h, the engine speed is ~ 2500 rpm which is where the red zone starts !! In reality, this is the sort of engine speeds used much (almost all !) of the time on the outstation highway coaches. -
A quiet bus is one that's not running.
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I was travelling on a new generation M-B (suspect to be IBC 1725) using MTrans coachwork via Transtar 1st Class & seated such that i could observe the readings from the instrumentation & driver behaviour etc.
As this is still very new bus chassi (mileage only 35000 km then) & under warranty, i have been told by another operator that the original settings as specified by the maker are not tampered with (yet perhaps !), which likely explains why i noted the tachometer needle could not exceed 2500 rpm, the start of the red zone for this model. The coach driver even showed his frustraution to the lady coach attendant on board by repeatedly pointing his finger @ the red zone beyond 2500 rpm grumbling something that they set the engine speed limit @ 'only' 2500 rpm mark & as such he could not drive faster then 120 km/h ! So of course for much of our journey from SGP to KL which lasted just over 4 hours nett driving time, i noted 120 km/h was shown on the speedometer & 2500 rpm on the tacho. I've no real reason to suspect the indications are inaccurate since the vehicle is still in brand-new condition & also due to what i've been told above. I've also riden in numerous not so new but older models of M-B & Scanias etc. & noted similar road speeds corresponded with similar engine speeds & of course the travelling time to cover roughly the same route was also similar ! That's another reasons why i do believe the readings on the gauges are reasonably accurate.
Shorthly before he was saying all that, we were overtaken by another M-B, the twin-exhaust piped OH 1627 L. I've riden this model many times & have seen the tachometer go well into the red zone, meaning little higher than 2500 rpm with the corresponding road speed around 130 km/h, which is maintained much of the time throughout my journeys ! I believe why our driver was grumblling afterwards was because he wants the engine speed limitation removed so that he could drive 'like the rest' i.e. well into the red zone so as to get the 130+ km/h road speed too so he won't 'lose out' !
I've also riden on the older Hino chassi before & noted road speeds ~ 135 km/h with corresponding engine speeds ~ 2600 rpm, of course well inside red zone.
So you see, what i've mentioned are based on what i've actually seen on my many trips aboard various makes & models of outstation highway coaches plying the SGP-KL route over the last 10 years. That's why i wrote earlier that the drivers tend to NOT observe the green zone simply because if they stay right in the middle of the green zone it'll only yield a road speed of 60 to 80 km/h, obviously to me too slow for prolonged long distance highway driving.
I notice on many models if they stay @ the end of the green zone before the start of the red zone, then they get ~ 100 km/h. But i'll say due to impatience & the perception (which i somewhat would agree) that even 100 km/h can be not productively fast enough sometimes on the N-S highway, they then tend to exceed into the red zone 'now & then' in order to get to 120 to 130 km/h ! I suppose watching the temperature gauge needle going up too much is likely the real reason why they know they better not be in the red zone too long @ any 1 time ! Not because they think they're going too fast or almost any other reasons.
So what i've mentioned above are the more realistic operating conditions many (outstation highway) coaches are subjected to. Blind eye seems to be shown to whatever theoritical 'ideal' green zone operating engine speeds etc. Instead the drivers all seem keen only in extracting every bit of performance out from the coach in return for completing their journeys as quickly efficiently safely as possible, having to juggle constantly with these factors as they drive & trying to produce the best combination outcome. How they treat the vehicle seems secondary to them ! That seems the widespread mentality, understandly so.
Surprisingly then it may seem that despite such 'extreme' operating conditions, i don't tend to see many breakdowns often ! But what i've seen quite a few times is that some drivers like to open the bonnet & 'expose' the engine presumably to cool it down while the passengers go to toilet & makan @ the rest stops along the highway ! I hardly observe such a practice with citybuses @ the terminals though.
Of course for coaches which are driven mainly or only within Singapore, these would have a much better life than those highway coaches above ! If you compare these (within Singapore use only hence low overall road & engine speeds driven) coaches with citybuses, then only would i agree that in such situations ONLY, the overall wear & tear levels on the citybuses would be higher.
Next time you take a coach to KL or Penang etc., make sure you get a good seat, to me that means a single seat either 1st or 2nd row where you get a vantage view of what's actually going on in the cockpit then observe the road & engine speeds & temperatures if possible. See then if my observations are accurate or not.Originally posted by The_Bus_Guide:Buses travelling at 120 km/h is OK but engine reaching 2500 rpm is not OK. The maximum power for even the best buses flats out at 2000 rpm (the actual start of the red zone). You can tweak the gear settings such that the bus is able to reach 120 km/h but I doubt that the engine will be revving until 2000 rpm, whatmore 2500 rpm. Its too dangerous, hardly ideal at all. -
aww come on guys..
u're all bus fans yea??
so to us a noisy bus is a quiet bus and a quiet bus is a bus that emits a sound far more solid than a BMW, far more pleasant than a Lexus and far nicer than a tuned Evo..
and that bus is none other than..
every bus in singapore!!