THROTTLE, MUD/SNOW, and REGEN buttons

[cofrari]

I was wondering what the purpose of the 5 buttons in the photo are and when do you use them?



I have an idea of of what the REGEN is, although in my 5-months of owning this bus I haven't had any reason to use them. When does the bus need a Regen? Does a properly functioning bus never need a Regen?



The THRTL buttons, I have no idea what the purpose would be. And the MUD/SNOW button, not sure what that does. Thanks!

[WIbluebird]

Most buses of that era are designed to regen on their own when the DPF filter gets too clogged.

That switch is there so in case it doesn't do it on its own the driver can initiate a regen. Don't do it unless absolutely necessary!!! It will kill your engine power and effectively immobilize the vehicle until the regen is complete.

Throttle/snow button may be for a locking diff but I've never heard of a bus having one. Throttle is probably cruise related.

[cofrari]

Originally Posted by WIbluebird

Throttle is probably cruise related.

I initially thought the Throttle was cruise related until I saw other pictures where buses actually have a CRUISE button. So now I'm feeling like it is something else. I'm hoping it is CRUISE, but I'm not thinking I'm going to be that lucky. And I haven't wanted to try it out not knowing what it would do.

[WIbluebird]

Originally Posted by cofrari

I initially thought the Throttle was cruise related until I saw other pictures where buses actually have a CRUISE button. So now I'm feeling like it is something else. I'm hoping it is CRUISE, but I'm not thinking I'm going to be that lucky. And I haven't wanted to try it out not knowing what it would do.

Well it appears that the button on the far left turns it on and the one next to it is for accelerating or decelerating. Someone that is more familiar with IC buses could tell you more about them. I mainly have experience with Bluebird which uses a different switch layout for cruise control.

[banman]

Originally Posted by cofrari

I initially thought the Throttle was cruise related until I saw other pictures where buses actually have a CRUISE button. So now I'm feeling like it is something else. I'm hoping it is CRUISE, but I'm not thinking I'm going to be that lucky. And I haven't wanted to try it out not knowing what it would do.

Most likely an adjustable idle feature. It will probably only function in 'N' neutral.

[elarryland]

The left two are cruise control and you can use them in neutral also to warm engine at higher RPM.
a triangle will light on dash when it's time to regen, if you are parked when it comes on push [parked regen] and don't turn motor off until finished.
mud/snow ? don't know.

[Booyah45828]

As others have said, the first 2 left-right are likely for rpm control. The rpm control buttons are likely for high idle, you might be able to do some programming and get them to work as cruise control as well, I'm not familiar with that new of an international.

The middle one might be for automatic tire chains(look back at the rear axle to see if you have them).

The right two are for dpf regneration. The inhibit button is for if you plan on parking in a hay field or some other place that is flamable, the other button is to initiate a stationary regen. The regen buttons shouldn't be messed with, unless, as I said, you're parking somewhere fire prone. Or if the dashboard informs you that a regen is required, you can flip the other switch and start a stationary regen.

[Drew Bru]

Originally Posted by Booyah45828

The middle one might be for automatic tire chains(look back at the rear axle to see if you have them).

That was my thought as well. You'll see several giant chains dangling down to almost the ground. The way they work is they whip around in a circle on the ground and whisk away snow/mud from in front of the tires.

[Sehnsucht]

I think most of your questions have been answered. If your bus is operating appropriately, it'll perform regens in motion but if it idles a lot the exhaust temp doesn't stay hot enough and eventually it could request a parked regen via some dash indicator. You can manually initiate a parked regen or inihibt a regen from occurring if it isn't appropriate at that time but it will impact performance and fuel economy.

The mud/snow button suggests either automatic chains or some sort of limited slip/locking differential but I would get more info before attempting to use it. In semis with locking diffs you cannot or should not engage them during a traction loss event, only as a traction-multiplier when you cannot get moving and even then they're marginally effective. I also though auto-chains were passive and self-deploying but there could be different types of systems out there I'm not familiar with.

Throttle and accept/decel do seem like cruise control functions or at minimum high-idle functions. If the bus originally had air conditioning I think this is common because AC-equipped coaches won't be able to maintain cooling effectively at normal idle ~500rpms so high idle can bump them up to ~850-900rpms to keep the compressors spinning. Cannot speak for AC-equipped school buses but that's how larger motorcoaches work.

[Johnny Mullet]

The mud/snow button could also change the trnsmission to start out in a higher gear in slippery conditions depending on the trans. Those left 2 buttons are totally cruise control and fast idle buttons which may be deactivated by the computer.

[Brad_SwiftFur]

From my experience in big trucks, some engines are programmed to auto shutdown after 5 minutes of idling (parked) but if "idled up" (from the usual 5-600 RPM to 700+, or whatever), it'll idle indefinitely. Also handy for cold weather warmup.


Not sure about the Mud/Snow switch, as others have said, likely either auto-chains, locking differential, or possibly an electronic traction-control system.


Use the Regen Inhibit switch if you are in a situation where a regen (with associated really high exhaust temperatures) is undesired, could pose a fire hazard, or if you are close to parking (shutting down). At that point you'll probably be close to needing a regen, though, which can be manually done when you're parked with the Parked Regen switch. What this usually does is tell the computer to check if a regen needs to be done (if not, it probably won't do it, I've seen it labeled as "Regen Request", which is a pretty accurate description), it is assumed that you have established it is safe to do so and you are prepared to remain parked for the time a regen will take (30-60 minutes). The engine will go into high-idle, you'll hear the turbo spool up and it will sound like the engine is under a heavy load, all in order to bring the exhaust temps way up to burn off all the soot in the DPF.


The last Volvo I had assigned to me, for a little over a year, needed a regen about once every 4 months. I can recall another truck I had that had an engine code, tried the regen request (it didn't regen), went to the Ryder shop (leased truck), the tech ended up giving it a forced regen (done through laptop diagnostic tools), otherwise the DPF would have had to come out for a benchtop regen (basically they stick the DPF into a big kiln and bake the soot out of it). Not cheap, which is one reason so many of us avoid DPF equipped buses in the first place.

[Sehnsucht]

I seem to recall someone else speaking from their experience at a school district which after they finished their routes would take a 30 minute 'regen run' because since school buses do a lot of stop and go they often don't get enough constant cruising time to auto-regen and their district found this added step of cruising empty was sufficient to reduce DPF- related maintenance expenses.

[cofrari]

Thanks everyone for all the feedback. For the Mud/Snow button: I don't have tire chains (didn't think I did but double checked last night). I'll have to research that one some more.



For the Throttle buttons: this an image I found online for a 2011 and the buttons clearly say "Cruise". That's what made me think that the "Throttle" buttons aren't actually Cruise Control (since my button doesn't actually say "Cruise" on it). Possibly they just renamed the buttons in later years?



For Regen: thanks for the advice with that. The EGR equipment was replaced in 2018, which was part of the reason I was OK taking the risk with this bus. I'm hoping I'm good with any emissions related equipment issues for my lifetime with this bus.

[Booyah45828]

Originally Posted by Sehnsucht

I seem to recall someone else speaking from their experience at a school district which after they finished their routes would take a 30 minute 'regen run' because since school buses do a lot of stop and go they often don't get enough constant cruising time to auto-regen and their district found this added step of cruising empty was sufficient to reduce DPF- related maintenance expenses.

I believe it was cadillackid that mentioned the city of columbus runs their busses on the interstate for a specific time to do what you describe.

We don't have to do that, we've got enough "country miles" on most of our bus routes that they'll burn themselves out. A few of them need the forced regens every now and again for whatever reason. I'm now wondering if it's because of the cold weather.

[WIbluebird]

Originally Posted by Booyah45828

I believe it was cadillackid that mentioned the city of columbus runs their busses on the interstate for a specific time to do what you describe.

We don't have to do that, we've got enough "country miles" on most of our bus routes that they'll burn themselves out. A few of them need the forced regens every now and again for whatever reason. I'm now wondering if it's because of the cold weather.

Same here, we have several buses that only run stop and go for 20 miles a day on their routes. Sometimes the mechanics will take them out on the Interstate or assign them to another driver for a school trip.

[Brad_SwiftFur]

Originally Posted by cofrari

Thanks everyone for all the feedback. For the Mud/Snow button: I don't have tire chains (didn't think I did but double checked last night). I'll have to research that one some more.

For the Throttle buttons: this an image I found online for a 2011 and the buttons clearly say "Cruise". That's what made me think that the "Throttle" buttons aren't actually Cruise Control (since my button doesn't actually say "Cruise" on it). Possibly they just renamed the buttons in later years.

It may be an electronic traction control system, some will sense wheel slip and give the slipping wheel some braking, to send some power to the non-slipping wheel.


The actual button/switch labeling may vary, but the function is essentially the same. The computer may have the "cruise" function disabled (which should be relatively easily enabled with the appropriate linkup and software).