Locking hand throttle...

[DracoFelis]

After spending way too much time trying to get a $200+ electronic cruse control to work in my CRX (several times we seemed so very close, but...), I finally told my mechanic to give up (and send the unit back for a refund) and go to "plan B", so I would have some sort of "cruse control" for my long road trip to Canada (my wife and I spent over 9 days in Ontario, and just got back).

As it turned out, my "plan B" was an inexpensive fully mechanical "hand throttle" (originally designed for off-road jeeps):
http://www.redrock4x4.com/shop/products/263.html

The thing does take a little getting used to (especially going up or down a hill, where you might want to slightly adjust the throttle position to avoid going too fast or too slow). But so far (I've had the thing a little less than 2 weeks, including a large road trip to Ontario Canada) I've found the thing to be surprisingly effective and easy to use. And it's also very easy to disengage quickly if/when needed (but unlike a real "cruse control", you do have to use your hand to manually disengage it, as it doesn't automatically disengage when pressing the brake).

And the real nice thing about it, is that it is fully mechanical, so puts zero additional load on the car (i.e. unlike a real/electric cruse control, this hand throttle puts no mechanical nor electric drag on the car, as it's essentially just a 2nd throttle cable). And the thing makes it trivial for you to have slow/even throttle pressure (which is also good for FE). And since the thing locks in place, you really only have to touch it if/when you want to change your throttle position. Because once you set the throttle level you want, that setting remains until you next adjust the hand control.

NOTE: If anyone is interested, I've attached a picture of how the thing looks mounted to my CRX's stick shifter. With this mounting position, the hand throttle can be very easily controlled with my right hand, whenever my hand is resting on the stick shift. i.e. I use the same hand position I've always used to shift gears (and still use to shift gears), to also adjust the hand throttle with my thumb and fingers. IMHO this makes the motions needed to adjust this new hand control much more "natural", as they don't require you to train a new hand position into your reflexes. And it also means that putting your hand on the stick shift sets you up to easily/quickly control either the gear shift and/or the hand throttle position.

[brucepick]

Slicker than owl snot!

[Telco]

Not the safest thing in the world, and any cops that recognize it will give you flak about it. If you have to suddenly slam on the brakes, the throttle will be held on, reducing braking time, and this will make you liable in any accidents. I'm pretty sure it's illegal to have a throttle lock that the brake pedal won't release on a vehicle used on public streets. You might think that you can release it in an emergency, but in reality people tend to grab the wheel with both hands and slam on the brakes in an emergency. "He might have stopped in time had he not had a manual throttle lock in place that held the gas on, reducing the vehicle's braking distance. Thanks to his illegal addition to his vehicle, Mrs. Jones and her baby will never see another day," the lawyer will say. Your argument of "But it saved me gas!!!" will fall on deaf ears.

I'd suggest seeing if you can work out a mod to it that will allow the brake pedal to release it. If it has a trigger lock you'd just need a cable from the brake pedal to the throttle cable, so that when you hit the brakes it trips the lock arm to release it. If it's a friction lock it'll be a little more difficult to set up so the brake pedal releases it.

[DracoFelis]

Originally Posted by Telco

Not the safest thing in the world,

IMHO that depends upon how it is used. On highways with little traffic, I don't see the problem.

After all, you really shouldn't be using any "cruse control" (including more traditional ones) when you are in traffic that could result in things happening "very quickly" (say under 3 seconds reaction time). And going from "lock" to "manual" (i.e. no "hand throttle") takes a small fraction of a second if/when your hand is already on the gear shift. And even when my hand is on the wheel, it still takes me under a second to move my hand from the wheel to the stick shift and also push down on the hand throttle (thereby turning the thing totally "off").

Originally Posted by Telco

and any cops that recognize it will give you flak about it.

If true, that could be a problem...

Originally Posted by Telco

If you have to suddenly slam on the brakes, the throttle will be held on, reducing braking time, and this will make you liable in any accidents.

If you are trying to brake against acceleration, than you will lengthen your braking distance, yes. OTOH you probably shouldn't be actively using the hand throttle when in traffic.

But also remember that this is a MANUAL transmission car. This means that the engine will likely "kill" if/when "slamming on the brakes" (with the car in gear) in an emergency. And once the engine dies (which will happen in under a second in a "slam on the brakes" situation), the throttle position has zero effect on braking distance. And if (as is a normal reflex for stick shift drivers, myself included) I press both the brake and the clutch (taking the car out of gear), than all the throttle lock could do (even if I should forget to turn it off) is to cause the engine to race a bit (i.e. no difference to braking distance, even if it isn't turned off, as the engine isn't connected to the drive shaft in that case)!

Originally Posted by Telco

I'm pretty sure it's illegal to have a throttle lock that the brake pedal won't release on a vehicle used on public streets.

I'm not saying you are wrong. However, I didn't find anything about this (doing an internet search on the subject) when I was looking (before buying the kit). And even if it is true some places, I'm sure that would be a state by state thing (i.e. part of the per state vehicle code, vs any sort of national law).

Originally Posted by Telco

You might think that you can release it in an emergency, but in reality people tend to grab the wheel with both hands and slam on the brakes in an emergency.

You are correct that is the stereotypical reflex response for the average person. Which means that until someone gets used to the thing, it would be more dangerous than using the more traditional (foot) control.

However, people tend (in an emergency) to do what they have trained their reflexes to do. And already in the few days I've used the thing, I've gotten in the habit of pushing the thing fully OFF (down) and switching to my foot whenever I see any traffic that I might have to deal with (i.e. whenever I see ANY patterns that look like they could possibly result in an "emergency" if something unexpected where to occur). So I'm already starting to get the automatic reflexes to disengage this device, when I "need" to.

Originally Posted by Telco

"He might have stopped in time had he not had a manual throttle lock in place that held the gas on, reducing the vehicle's braking distance. Thanks to his illegal addition to his vehicle, Mrs. Jones and her baby will never see another day," the lawyer will say.

Whenever there is a tragic auto-accident, the lawyers are all set to come out with heart wrenching testimony. I'm sure that the picture you paint is no more damaging than any of a number of other "it's his fault" pictures out there. Just think about all the "If only he wasn't on his cell phone", or "If only he saw me", or "If only she hadn't dropped her cigarette", or even the "If only he hadn't fallen asleep" lines out there.

The truth of the matter is, learning how to drive for FE both with and without FE mods (such as this hand throttle) requires you to be a more attentive and DEFENSIVE driver to begin with (as you gain FE by ANTICIPATING the traffic). So properly used, you are probably a much safer driver with such devices, than most drivers are without them...

Originally Posted by Telco

Your argument of "But it saved me gas!!!" will fall on deaf ears.

But that probably would NOT be my argument.

Since I'm already a fairly "defensive driver" (and becoming more so, the more I learn about FE driving), I likely would have already disengaged the locking control at the first sign of things being marginal (i.e. when there were opportunities for something to "pop up" with less than a few seconds to deal with them). As such, I could truthfully counter-argue that the thing wasn't even engaged at the time, and therefore had zero effect on how fast I could brake...

Originally Posted by Telco

I'd suggest seeing if you can work out a mod to it that will allow the brake pedal to release it. If it has a trigger lock you'd just need a cable from the brake pedal to the throttle cable, so that when you hit the brakes it trips the lock arm to release it. If it's a friction lock it'll be a little more difficult to set up so the brake pedal releases it.

Sounds like a decent idea, if I can come up with some mod that isn't too big of a PITA to do. And you are correct, that it would deal with the "safety issue" of forgetting to disengage the throttle in a braking emergency (thereby making the thing at least a little safer).

However, the "lock" in my particular hand throttle (and the thing really is a hand throttle, not just a throttle lock, in the you really can control throttle speed with just your hand, if you so choose) is friction based (not trigger based), so it's not going to be the trivial cable setup you described to disenguage it from the brake pedal.

[GasSavers_Red]

FWIW lots of jeepers run the RE hand throttle and I have yet to hear about any case where someone died because of it....

[Telco]

Very long post. I wasn't necessarily trying to ding you on this, it looks like a nice little mod. But, due to its method of operation it looks like it could cause other problems, and since these particular problems can cause possible loss of life or limb, or cause a hard hit on the finances, I felt it was better to point them out along with a possible solution.

Since it is a friction based lock, all it would need is a second cable that could pull the handle back down. It would need to have enough strength to overcome the friction and pull it all the way to a stop as soon as the brake was touched, but not pull the handle apart in a panic stop. I don't know the best way to build something like this, but a do have an idea.

You'd need a servo that pulls and pushes, and a cable. The servo would need to be able to pull far enough, instantly, to completely pull the throttle lock to its fully released position. A slide attachment like the throttle cable uses for cruise control would be an ideal attachment for this, in fact you could use a cruise control cable for it if you can find one long enough. Set it so that when the servo is pulled out, the servo is at the far end of the slide and the throttle is fully open but not being stressed. Hook the servo control line so that when it sees power, it retracts the servo to release the throttle lock, and when power goes away it goes far enough in the opposite direction to allow full throttle to be locked.

The circuitry to make this work shouldn't be too hard but you'd need an electrical engineer type to design it. Ideally it should recognize the input power state from the brake line, then apply full power to the servo to fully extend or retract, then cut power to the servo once it's fully extended/retracted. Electric door lock motors might work for this if the travel is far enough. And, the servo could be mounted inside a small insulated box in the engine bay to keep interior noise down. Since the device would be cable operated, it would be pretty easy to route and the orientation of the servo to the throttle would not matter.

Good luck with it, just plan for the worst and hope for the best.

[skewbe]

The only problem I see is that you could possibly over-rev your engine if you lose your wits.

Lots of cars use them, emergency vehicles use them, airplanes use them, motorcycles use them, boats use them, lawn tractors use them. I don't see any good reason to over complicate it if you just use it on the hiway. Heck, my throttle sticks open frequently (gotta fix that), but it isn't very intimidating in a geo

[cfg83]

DracoFelis -

Thanks for publishing this. If I cannibalize my cruise control for other nefarious purposes, I may install this.

Seeing the picture of the CRX stickshift makes me nostalgiac, .

CarloSW2

[Mike T]

Hmm, I am glad that I have factory cruise control in my smart!

[Bill in Houston]

Originally Posted by skewbe

The only problem I see is that you could possibly over-rev your engine if you lose your wits.

Ya, in a panic situation instinct says boot the clutch, stomp on the brakes, and ask questions later. So I am wondering if the CRX has a rev limiter...