19.01.2006
Shore team commentary Andrew Roberts
Thursday 19 January 2006 18:19 Changing the Generator Injectors
Dee has described changing the generator injectors recently
and so it may be helpful to give a little more detail.
The injectors in a diesel engine squirt a very controlled amount of fuel into each cylinder. The fuel is pumped through the injector at extremely high pressure, which results in the diesel oil being atomised as it enters the cylinder. The very high compression created as the piston rises in the cylinder causes the fuel to explode so forcing the piston down. If the fuel isn’t properly atomised the efficiency of the engine drops dramatically and can lead to other problems.
An indicator that the injectors need servicing or changing is often black exhaust smoke. Most marine engines have a recommended number of hours between injector servicing, in the case of Dee’s Northern Lights generator this is 400.
All the major mechanical components on a Challenge Yacht are designed and laid out so as to be easily indextained at sea and in harbour. The generator is mounted on a platform over the index engine with the injectors at eye level and all the key components in easy reach.
Removing the injectors and fitting new ones is a fairly straightforward job for an experienced engineer when the yacht is moored alongside a marina. It is however, a rather more difficult job when bouncing around in the Southern Ocean, with the yacht healed over at twenty degrees and any tools or components ready to slide away or drop into the bilge if not carefully placed.
Changing the quite delicate injectors involves removing various hoses and steel pipes which drip smelly diesel oil, before unbolting and prising out the injectors from their recesses in the cylinder head. On a good day an engineer would take an hour or so, but at sea it could take two or three times as long by the time everything is carefully reconnected, the fuel bled through and clean up finished. The really nerve- racking part is turning the key and hoping that the engine fires and runs smoothly. A few seconds feel like eternity and Dee will have felt real and justified elation knowing that the engine, which provides all her electricity and water, is running efficiently and economically. Definitely not a girlie sort of job, and one which most people (including Dee) would strenuously avoid if possible.
Confused by any of these terms? Read our Glossary
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