Fuel pump and injectors

Going through the licensing process ? Have queries, comments, or do you need an answer to that obscure exam question ? This is the place to post.
Knowmarine
Bilge Dweller
Posts: 2
Joined: Mon Jan 20, 2014 2:36 am

Fuel pump and injectors

Postby Knowmarine » Tue Mar 11, 2014 12:14 am

Good day sir

I would like to know is there any differences in 2 stroke and 4 stroke marine engine fuel pump and fuel injectors? Can't seem to find the answer on web, highly appreciated if anyone could tell me. Thank you

User avatar
D Winsor
Superintendent
Posts: 325
Joined: Thu Nov 22, 2007 8:23 am
Currently located: Dartmouth

Re: Fuel pump and injectors

Postby D Winsor » Tue Mar 11, 2014 4:00 am

The simple answer to your question is there is no difference between the injectors and fuel pumps for a 2 stroke or 4 stroke engine.

There are numerous variations on the basic design of the cam driven Bosh plunger & barrel type fuel pump fitted to most engines with respect to how it is controlled to regulate the amount of fuel injected per stroke, and how it may be mounted on the engine as either independent pumps for each cylinder or number of pumps, 1 per cylinder, mounted in a block assembly or combination pump & injector assemblies activated with a rocker arm. The exception being many of the more modern engines fitted with electronically controlled injection systems, these engines have what is known as a "Common Rail" fuel system and a high pressure booster pump is used to supply fuel to the injectors which can be driven directly by the engine, by an electric motor or a combination of both.

Injectors are designed to be opened mechanically, electronically or by fuel pressure pushing against a spring. All do the same job, supply a fine spray of atomized fuel through a nozzle to the cylinder, so it makes no difference if the engine is a 2 stroke or 4 stroke.
Troubleshooting 101 "Don't over think it - K.I.S.S. it"

User avatar
Big Pete
Engineering Mentor
Posts: 790
Joined: Fri Apr 24, 2009 11:18 pm
Currently located: Solihull, England

Re: Fuel pump and injectors

Postby Big Pete » Thu Mar 13, 2014 12:18 am

The difference between the Two Stroke and 4 Stroke Engine is that with the 2 Stroke fuel is injected into each cylinder every revolution of the crankshaft with the 4 stroke it is injected every second revolution.
This is achieved by having the camshaft run at crankshaft speed on the 2 Stroke and gearing it down to half crankshaft speed for the 4 stroke, obviously this is for mechanically driven pumps/ injectors. Where the injection is electronically controlled this is of course done electronically.
BP
It is always better to ask a stupid question than to do a stupid thing.

Knowmarine
Bilge Dweller
Posts: 2
Joined: Mon Jan 20, 2014 2:36 am

Re: Fuel pump and injectors

Postby Knowmarine » Thu Mar 13, 2014 8:43 pm

Really appreciate the insight and sharing from you all sir.


Return to “Training Room”

Who is online

Users browsing this forum: No registered users and 1 guest