Starting a modern diesel engine, in cold weather, is now much the same as starting your automobile. Even more so with the larger diesels like the Cummins ISM and ISX, which do not use any electronic heating aids that require a start wait time. This, however, has not always been the case in both earlier and some other diesel applications.
Caterpillar’s answer to cold start ups on engines mainly used in the construction industry back in the 60’s, employed a “Pup” motor. This single cylinder gasoline engine was mounted near the flywheel and was usually started using a hand operated crank. Once running, a manual clutch was slowly engaged that drove a pinion that turned the main engine. Soon after the big diesel started to be rotated over and over, a plume of white smoke would belch out of the exhaust followed by an accelerated roar. The pup engine clutch was then disengaged and the little motor turned off. The big Cat was running.
International’s answer for cold starts on similar equipment back then was a little different. The big diesel actually had a set of spark plugs like a gasoline powered engine. It also had two fuel tanks, a large diesel and a small gas. A very small hand operated crank or knob was turned all the way in one direction. This somewhat relieved the compression and introduced straight gas to the electrically cranked engine. Once started and slightly warmed up, the crank or knob was rotated in the other direction. This returned the engine compression back to full as diesel fuel was introduced through the injectors. The gas flow was then totally disabled and the diesel engine was running and ready to work
Additionally, cold weather starting aids like hand bombed ether and ether injectors were used. Today, use of ether is not recommended as a start aid and can even be very dangerous if used on heated intake grid equipped engines. Ether was also know to bend or break connecting rods as well as cause other internal damage.
So, in comparison, our diesels today, whether they are equipped with glow plugs, heated intake grids or pre-combustion chamber designs, are a far sight simpler and safer to operate. They are all direct electric start. 12 volts for all engines up to a given size, then 24 volt is used as the amperage required for the 12 volt becomes impractical as far as cabling size and heat build up.
Next time you start up your diesel, think of all the work and development that has gone into making what we probably take for granted; a quick, no fuss, start.
There are many components that contribute to smooth cold starts from the ECM (Electronic Control Module) to even the fuel composure of today. So, even though we think it can’t get any better than this, it will. Design improvements in diesel development will inevitably gallop on.
Note: The winter photo was taken at the Spartan’s Charlotte, Michigan service camp area, on January 1, 2008.
With A Starting Thought – Lug_Nut – Peter Mercer