Monday, December 05, 2005

Diesel Engine Shutdown System by 'Kysor Cadillac'

Diesel engines are at times costly to repair and more so if they have to be totally rebuilt or replaced. So it makes sense to protect your diesel engine with an automatic engine shutdown system. Diesel engines have fuel shutdown solenoids on the injection pump that shuts down the fuel supply instantly. In normal circumstances the fuel solenoid is operated by the key switch but there is a system that monitors coolant temperature and oil pressure while operating your diesel engine that automatically shuts it down before major damage happens. A lot of our buses have KYSOR shutdown systems installed which safeguards against running a diesel engine over the 220 degree coolant temperature or below the 3 psi oil pressure limit.


  • key switch sends run and start voltage to KYSOR control module
  • control module sends voltage to COOLANT ALARMSTAT
  • ALARMSTAT relays voltage to OIL PRESSURESTAT

When coolant temperatures reach 220 degrees or oil pressure drops to 3-5 psi, an open circuit to the fuel solenoid instantly shuts down engine. The built in alarm system warns the operator that there is a problem! So at this point it's easy to see the advantages of this system, if you've ever experienced an engine failure it becomes apparent how valuable a diesel engine shutdown system really is! It comes down to bottomline $$$ Every truck fleet or owner/operator would benefit in a big way with this shutdown system in place.

So if you're ordering a new truck for yourself or for your fleet, I highly recommended including a diesel engine automatic shutdown system.

Below is the Control Module/Automatic Override for the Kysor shutdown. It serves as the brains of the operation supplying battery voltage and operating the shutdown system in the Run and Start mode.

The Coolant Alarmstat is pictured to the right, it monitors coolant temperature. When diesel engine temperatures reach 220 degrees it switches internally to sound the alarm and dashboard warning lamp as well as shutting engine down. Note: We've had a few situations in our fleet where the diesel engine shuts down for no apparent reason at normal operating temperature. Everytime the fault has been with the Alarmstat.

Finally the Pressurestat monitors diesel engine oil pressure which also internally switches to the alarm circuit when oil pressure drops between 3-5 psi [various pressures available by part #] to warn the operator and automatically shuts down the engine. This system is essential for anyone who cares about their business or fleet operation with less down-time and money spent on repairs that could have been prevented!


b2zone said...

Super information. I have a 1994 International Truck with a L10 Cummins with a factor installed Kysor System. Each sensor has 3 wires. My question is how do you test this system without replacing a the two sensors. These babies are 140.00 bucks each from Internationl Truck.

Anonymous said...

remove wires from terminals, mark down if n/c or n/o, other is "c"common.
hook multimeter to c-n/c, should read in ohms position, hook to n/o and c, should not till engine is running, start engine to check, keep all hands and wires clear of moving parts! that is it,if they are leaking they must be replaced.

see tong cheng said...

teamdHy gazeAccording to the above electrical diagram,
To test Alarmstat:
Engine running, use a wire shorted across Terminal C and NO.
Engine should shutdown with alarm & warning light.

To test Pressurestat:
Engine running, use a wire shorted across Terminal C and NC.
Engine should shutdown with alarm & warning light