| Author | Message | ||
| Bruce Henderson (Oonrahnjay)
Registered Member Username: Oonrahnjay Post Number: 519 Registered: 8-2004 Posted From: 70.60.107.49  Rating: N/A |
I have been looking for electric/electronic speed control equipment (accelerator pedal and associated and engine/fuel injector and associated items). It appears that there are such things for gasoline engines (actually "drive by wire" accelerator and throttle-body components) and electronically-controlled engines but I have neither. There is a plain lever which extends from my fuel injector pump; the point of actuation moves approx. .60" from idle to full-fuel. I don't know how much pressure, but I can easily take one finger and move this speed control lever back and forth. Does anyone know of a vendor of pedal and actuator components that would work on my engine? Thanks, BH NC USA | ||
| Jack Campbell (Blue_goose)
Registered Member Username: Blue_goose Post Number: 139 Registered: 5-2007 Posted From: 71.101.168.79  Rating: N/A |
I think what you need is a air throttle. All of the electronic engines use electronic throttle's but I haven't seen one used for anything else. That dosn't mean they don't make one just I haven't seenone. Air throttle's work very good and you can pick them up easy. Jack | ||
| Jim Shepherd (Rv_safetyman)
Registered Member Username: Rv_safetyman Post Number: 295 Registered: 1-2004 Posted From: 67.142.130.38 Rating: N/A |
Bruce, when I first read your post (too quickly), I thought you were wanting to make an attempt to convert a mechanical engine to electronic. However, it looks like you are trying to get a cruise control system for your mechanical engine. The unit of choice seems to be the King Cruise (http://www.cruisecontrolking.com/). When I had a mechanical engine, I looked at the system and it seemed a bit pricey to me. Some folks adapt a very popular car type system made by Rostra (http://www.rostra.com/cruise-control.htm). They use an electronic servo, so you don't need to deal with a vacuum type servo. I have used their systems on several vehicles including a class 7 diesel truck conversion. Always had good luck with their systems. I just installed one of their systems on my service truck. When I looked at their site, they had really migrated towards addressing electronic engined cars. However, the basic system is still the same and would work on a bus. As I recall, there was a huge difference between the cost of the King and Rostra units. The biggest issue is how you would pick up a speed indication. They have a great technical support group and I think they could help you figure that out. On cars you used to put magnets on the drive shaft and mount a pick-up to read the frequency of the magnets passing the sensor. I think most bus transmissions have a provision for mounting a sensor on the rear tail shaft. If so, that can probably be made to work. I think you will want to connect the actuator to the front pedal mechanism. The issue here is whether there is any "drag" in the cable/linkage from age and lack of maintenance. If the lever you mention is easily accessible, you can probably use it. If the throw is too short and needs too much pull, you can probably weld/bolt an extension on it. If you use an extension, I would make is with several holes so that you can tune the system. The Rostra has a reasonable pull capacity, but the issue may be that it is designed for something like 1-2 inches of travel and it would not work well with a short throw system. I know that bus folks have used the Rostra system - maybe they will chime in. Jim | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 169 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
I have an air throttle with Allison automatic (V730). Because of the transmission throttle modulator being air operated also, I couldn't mount the King Cruise in the engine compartment (if I did, the transmission would not shift right since it would sense idle position when cruising). I just made a small metal extension of the gas pedal and mounted the pull cable for the King Cruise on that pulling on the gas pedal with the unit mounted in the dash on the passenger side. The only real problem I had was to get the brake lights to talk to the unit since I have LED lights that don't create enough resistance. A 100ohm resister grounded resolved that. I have been very pleased with the King Cruise, and with its' additional feature of being able to use it for fast idle. Good Luck, TomC | ||
| Bruce Henderson (Oonrahnjay)
Registered Member Username: Oonrahnjay Post Number: 520 Registered: 8-2004 Posted From: 68.84.6.83 Rating: N/A |
Thank you all for your comments. Jack, does an air throttle work before the system is "aired up". And what is the lag like? Jim, thanks for that info - and I guess I will be looking for a cruise system later - but now I have nothing between my right foot and the lever on the fuel injection pump on the engine. I'm looking for a basic "throttle" (hate to use that word with a diesel but you know what I mean) system to link up the two. I'm guessing that an air "speed control system" will be the way to go. | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1208 Registered: 12-2000 Posted From: 74.4.63.215  Rating: N/A |
Differnt Jack, but to answer your question, on our MC-8/8V71 it takes about 30 PSI air pressure before the air throttle will function. The lag is not much and easy to get used to, similar to air brake lag. Jack | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1079 Registered: 7-2006 Posted From: 75.209.173.73 Rating: N/A |
"...similar to air brake lag..." Not sure I understand that statement. Ours, to the best of my knowledge, do (does) not "lag"...if it did (does), seems like air would not be a great choice. When we hit the brake, it functions (or not  ) immediately if all is kosher. Just does not make a whole lot of intelligence to me...about a lag. Or?  RCB (Message edited by Chuckllb on January 22, 2010) | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 1209 Registered: 12-2000 Posted From: 74.4.63.215 Rating: N/A |
RCB, I was told there is a slight brake lag, although virtually imperceptable, because the rear brakes are controlled by a relay valve that receives a "signal" from an air line that comes from the service brake application valve at the driver's foot. So it takes time for the air signal to travel to the relaly valve and then for the relay valve to open to allow air to flow to the rear wheel brake cans. Maybe BW or someone with more air brake expertise can give a better explanation. Jack (Message edited by JackConrad on January 23, 2010) | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 482 Registered: 10-2003 Posted From: 74.244.14.221  Rating: N/A |
There is definitely brake lag. Think about when you release the brakes after a stop....there is a split second until the air can exhaust | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1789 Registered: 12-2000 Posted From: 76.68.135.250  Rating: N/A |
There is somewhere shorter than 2/5 of a second delay between opening the brake treadle, and something meaningful happening at the wheel ends. We humans aren't too good at feeling a delay of such short duration. However, at 30 mph, 2/5 of a second is close to 17 feet of travel, which is a lot of distance if you need it at the end of the stop! The brakes take a more noticeable length of time to release than apply, as the return springs don't motivate the air to leave as well as the pressurized air in the tanks motivates it to enter. An air throttle will have some very slight delay in activation as the air travels back and forth filling into and emptying out of the actuator back at the engine, from the foot pedal up front. When the suggested line and fitting sizes are used, throttle response should not be particularly noticeable. happy coaching! buswarrior | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 1080 Registered: 7-2006 Posted From: 75.210.176.94 Rating: N/A |
As usual...good post BW...thanx. RCB | ||
| Bruce Henderson (Oonrahnjay)
Registered Member Username: Oonrahnjay Post Number: 522 Registered: 8-2004 Posted From: 68.84.6.83 Rating: N/A |
OK, back to the subject of speed control mechanisms ... would the users of air "throttles" please comment: Do you experience any "lag" in your air throttle? Does the time it takes to air-up your throttle give you any real-life issues? | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 839 Registered: 8-2006 Posted From: 74.32.95.26 Rating: N/A |
Bruce, air throttles are adjusted to your prefence by air pressure some like a little lag and some don't.I for one don't it is all going to depend on your driving style set it where ever it suits you best good luck | ||
| Bruce Henderson (Oonrahnjay)
Registered Member Username: Oonrahnjay Post Number: 523 Registered: 8-2004 Posted From: 68.84.6.83 Rating: N/A |
Thanks, LRB. That's good info to know. My bus is an "auto" like transmission (planetary gears with bands and a bolt-on torque converter) but is manually shifted. To get good shifts, the accelerator must be pretty closely timed to the road speed changes. (Actually, the old hydraulc system was pretty good for what it was meant for but when things are stuck so badly that you break pieces getting them apart so that you can rebuild them, then you know it's a bad system. But it had been clearly ignored on the maintenance before I got it.) |