Integrating Jake Brake and Cruise Control on Detroit Diesel

[georgecederholm]

Just a quick post to see if anyone knows this before I start checking with my Detroit Diesel shop and have them laugh at me…

I remember (I think!) from years ago that some of the early-to-mid-2000s Windsors (Dave O, maybe) were programmed to automatically engage the exhaust/engine brake if speed increased a set MPH a over the cruise control speed value, while the cruise was engaged. I seem to recall that this was done via the engine software parameters. This generated mixed opinions, of course, and I didn’t pursue it at the time.

So, my question is: does anyone know if this kind of setting is generic enough that it might be available on a 2004-built Detroit Diesel Series 60? We have changed toads (complicated story) and the new one cautions against speeds over 65 MPH. I know that’s not an absolute, but I’m used to letting speeds get up to the mid-70s on moderate long downgrades, and I’m fussing a bit to keep things in check. I know that cruise and Jake can interact well, since my Vorad system will apply the Jake if needed to maintain distance with a slower vehicle while the cruise is on.

Thanks in advance…

[JDCrow]

Mid 70s on downgrades. Be still my heart. I wish I had more to add, other than jealousy 

[Frank McElroy]

I don't know about a Detroit diesel but on a Cummins, that feature exist for most engine models.  The ECM feature is set via the Cummins Insite software by turning on the feature and setting the speed in terms of MPH above the cruise control set speed that it will turn on the Jake brake.  You must also turn off the feature that automatically cancel the cruise control so that the cruise control automatically resumes after the Jake is turned off.

[vito.a]

The issue with this is engaging the Jake brake disconnects the cruise control. 

The engine and trans communicate over the SAE J1939 bus using  a specified interface.  So, if it can be done Allison would be the folks to talk to.  

Does your Executive have the console mounted Jake, or the foot pedal?  Many folks prefer the foot pedal as you can engage it with your left foot and keep both hands on the wheel.  Maybe adding a Jake brake foot pedal would help.  

Frank's correct.  Monaco kept the Windsor a "lighter" weight diesel without a tag axle.  The early Windsor had the Cummins 5.9L, then in mid 1996 they upgraded to the C8.3L.  In 1998 they used the Cummins ISC (electronic version of the 8.3).  In 2003 they upgraded to the Cummins 8.9L ISL.

[georgecederholm]

1 hour ago, vito.a said:

The issue with this is engaging the Jake brake disconnects the cruise control. 

The engine and trans communicate over the SAE J1939 bus using  a specified interface.  So, if it can be done Allison would be the folks to talk to.  

Does your Executive have the console mounted Jake, or the foot pedal?  Many folks prefer the foot pedal as you can engage it with your left foot and keep both hands on the wheel.  Maybe adding a Jake brake foot pedal would help.  

Frank's correct.  Monaco kept the Windsor a "lighter" weight diesel without a tag axle.  The early Windsor had the Cummins 5.9L, then in mid 1996 they upgraded to the C8.3L.  In 1998 they used the Cummins ISC (electronic version of the 8.3).  In 2003 they upgraded to the Cummins 8.9L ISL.

Vito,

Well, if I do try to get it changed, it’ll be at W.W.Williams, the Detroit/Allison shop in Phoenix, so they should be able to handle both sides.

That said, at least Frank has confirmed what I thought I remembered: it’s possible on electronic Cummins engines, at least those used in some models. And my configuration already allows concurrent Cruise and Jake use as that’s the way the Vorad system works.

As far as my setup, my 2005 Exec does not have the foot pedal but rather two Carling switches (On/Off, Hi/Lo) on the armrest console. If I pursue the change, I’ll ask about moving the switch to see if that makes a difference.

Thanks,

3 hours ago, Frank McElroy said:

I don't know about a Detroit diesel but on a Cummins, that feature exist for most engine models.  The ECM feature is set via the Cummins Insite software by turning on the feature and setting the speed in terms of MPH above the cruise control set speed that it will turn on the Jake brake.  You must also turn off the feature that automatically cancel the cruise control so that the cruise control automatically resumes after the Jake is turned off.

Frank,

Thanks for confirming what I thought I remembered. I knew I recalled that multiple settings were needed. I’m not sure how my Vorad is configured to engage the Jake without cancelling the Cruise, but I know it’s possible.

Thanks,

[Frank McElroy]

On the Cummins engine, all the settings for controlling the use of the Jake brake while in the cruise control mode are in the engine ECM. 

If you want the automatic use of the Jake brake while using the cruise control the technician will use the Cummins Insite software to enable the cruise control and engine brake interaction feature, set the MPH above the set cruise MPH setting to activate the low Jake brake (typically +5 MPH), set the MPH above the set cruise MPH setting to activate the high Jake brake (typically +8 MPH), and to enable the cruise control auto-resume once the Jake brake slows the coach down close to the cruise control set speed. 

The engine ECM will also command the transmission to downshift typically to second gear while using the Jake brake.  The transmission TCM will protect itself and only downshift when safe to do so without over revving the engine (<2700 RPM for an ISL).

[SigPIlot]

Not sure if it requires a "configuration" having never had one done, but my DD60 will automatically engage when over speeding the cruise control setting. Can't remember what the criteria is but probably around 5-10 mph. I'll have to check next time I find a hill worthy of speed generation (lol). Out west lots of hills. not so much in FL.

[willbo777]

Just to add another two cents.  On our DD Series 60 on cruise, going downhill it will go as fast as you let it, but with Vorad if there is a vehicle in front of you, it will engage the Jake.

[georgecederholm]

On 10/20/2021 at 6:35 AM, SigPIlot said:

Not sure if it requires a "configuration" having never had one done, but my DD60 will automatically engage when over speeding the cruise control setting. Can't remember what the criteria is but probably around 5-10 mph. I'll have to check next time I find a hill worthy of speed generation (lol). Out west lots of hills. not so much in FL.

Hugh,

Thanks for confirming that what I'm looking for may be possible. I will pursue this with my local DD/Allison shop over the winter.

On 10/20/2021 at 1:21 PM, willbo777 said:

Just to add another two cents.  On our DD Series 60 on cruise, going downhill it will go as fast as you let it, but with Vorad if there is a vehicle in front of you, it will engage the Jake.

Bill B2,

Thanks; that's exactly how ours works now. I'm essentially looking to keep that but add the same effect based on MPH over the cruise setting.