How to restrict DF40A performance with an electronic signal

[benmbh]

We run a hire fleet using DF40A and a few DF20A's. I have GPS modules on the vessels that can activate a 12v signal based on certain conditions and i'm looking for a way in which I can somehow reduce the performance of the engine.

Our use case would be something like this. GPS shows customer is speeding, they don't answer their phone, we activate a signal, engine goes into limp mode, customer has to call us.

Any kind of advice would be appreciated. I thought a way to put the engine into limp mode or troll mode could potentially solve the issue. We use mechanical cables, no fly by wire at this stage although if there is a more elegant solution using FBW i'm interested for the future.

[Moonlighter]

Fly by wire is not available on any Suzuki outboard less than 115hp so thats not even an option.

Its an interesting concept to remotely activate “safe mode” or similar and it will be interesting to hear if you figure out a (economical) way to do it.

Apart from “safe mode” the engines also have a neutral throttle switch on them. Simple on/off switch. If the ecu doesnt see a signal from that switch when the engine is put into gear it will limit rpm to around 3000revs to prevent the engine being over revved in neutral. Maybe you can figure a way to override that switch remotely …..

[Pbodsw]

I've seen vehicle trackers that can remotely immobilize the ignition using a digital output to operate a 12v relay. You have something similar. In that case use Moonlighter's neutral wire suggestion and break it's circuit through the relay when the signal is sent?
https://www.rewiresecurity.co.uk/driver-identification
RewireDB1_copy_1070x974.png

[benmbh]

My main concern is I don't want to isolate the engine entirely and put the customer into a dangerous situation, these are boats out on the water. Hence why i'd only like to reduce power. If I cut the circuit to the neutral switch while it's running will the engine simply cut out?

[Solarman]

I would think, if you interrupt the neural switch on the motor, making it believe it is in neutral, then it should limit the motor to 3000 rpms in any position F-N-R?

[cprice11]

Can you govern it so it won't go to full throttle?

[Moonlighter]

My main concern is I don't want to isolate the engine entirely and put the customer into a dangerous situation, these are boats out on the water. Hence why i'd only like to reduce power. If I cut the circuit to the neutral switch while it's running will the engine simply cut out?

The neutral switch is a simple momentary switch, its is either on or off. When the gear linkages move, the switch changes from on to off. Or off to on. Whatever.

We occasionally see members come on here and say that they start their engine but when put into gear, the engine wont rev past 3000rpm, and the usual cause is that the switch is loose or broken. The ecu doesn’t see the signal to tell it the engine is now in gear. So it wont let the engine rev past 3000rpm.

To get this to work at the least you are going to need to have a internet data connection set up on the boat and then a secure access so you can use something similar to the remote immobiliser to, for example, somehow turn that neutral switch off - which will then limit the engine to 3000rpm. Going to take some doing, all of that….

Its a lot of trouble to go to to solve - what problem?? How big a problem? How often? What are the consequences?

May be time to start back at the beginning and do a proper risk assessment?

Risk = likelihood x consequences. Then consider the options for mitigation strategies. The solution being considered now may turn out to be overkill for the risk involved.

[benmbh]

Can you govern it so it won't go to full throttle?

We already have that, they're limited as per legal regulations for hire boats in Australia, maximum of 10 knts with 1 x 80kg adult aboard.

To get this to work at the least you are going to need to have a internet data connection set up on the boat and then a secure access so you can use something similar to the remote immobiliser to, for example, somehow turn that neutral switch off - which will then limit the engine to 3000rpm. Going to take some doing, all of that….

We already have all this setup, we have GPS aboard connected to the internet with a sim card. We can communicate with the device and control a relay on and off etc. The last piece is what to control on the engine.

Its a lot of trouble to go to to solve - what problem?? How big a problem? How often? What are the consequences?

Anything above 4 knts speed over ground creates a lot of wash with some vessels, especially when going against the tide.
It's the number one cause of complaints for our business from canal residents, there is no inherent risk other than it creates a very negative image of our business and the complaints are pretty much endless. We've tried to control this in many other ways, bonds, education, warnings, signage, blacklists etc but it doesn't help, some people just don't care about the rules.

[Solarman]

If you can communicate to turn a relay on/off, then you just need to interrupt the neutral switch wire on the motor to limit the motor to 3000 rpms, not sure what speed that will be on your boats, but it's like a high idle in any gear position. With the GPS function, it might be possible to set it up automatically for certain travel areas? Outside of those certain GPS areas the relay could be turned off allowing the motor to run normally? Though you might need a secondary relay/switch to prevent full throttle (unless the throttle is lowered) when the GPS turns off. Or, maybe a relay that operates a solenoid (added) to block the throttle from going only so far in those GPS areas? Might add a flashing light to same relay to indicate "slow speed zone"?

Good luck with all that.

[Moonlighter]

Now that you’ve mentioned the 4 knot limit, the neutral switch isnt going to be the solution - 3000rpm will be way too fast.

Maybe another option might be to have an annoying buzzer going off whenever the boat exceeds 4 knots in the canals? That will get the attention of the driver!

[Murray]

https://www.suzukioutboardforum.com/...ki-owner-df40a

The above link won’t help you with wake in the no wake zone but you may be able to “detune” the engine to reduce overall speed?