Turbocharging a diesel engine?

there's tens of thousands of 100rpm diesels out there happy with turbos.
so its horses for courses

 

The engine in question is a mid 80s Yanmar turbo 6 cyl 175hp. Always been against under loading but unless one repowers your'e stuck w what's out there.
I'm hoping I can run a Nordic 32 at 7.5 knots and 2 gph. Any opinions on that?

Easy

 

"The engine in question is a mid 80s Yanmar turbo 6 cyl 175hp.
I'm hoping I can run a Nordic 32 at 7.5 knots and 2 gph. Any opinions on that?"

NO Sweat , I believe the Yan is just a Toyota truck transplant , and auto /truck engines advertise a completely unrealistic peak HP.

A rating that could NOT be sustained even for an hour , unlike an industrial engine where 175Hp IS 175 HP "Forever".

AS a guess I would think the Toy engine is 120 to about 150 Cubic inches , so a long term rating of 60 to perhaps 75 hp would be realistic , although unlikely to be seen in pickup truck service, unless towing a trailer up hill.

2 GPH of burn is 30 or 40 hp at best , just what the Toy folks had in mind trucking down the road.

FF

 

Jonny88,

I am surprised you cannot find this in the internet as turbocharging is very common. You will find single turbo, dual turbo, multiple turbo, dual cascaded with waste gate, ect.

Turbocharging is the easiest way to boost horsepower of a normally aspirated engine at the expense of reliability or voiding the warranty.

If you are looking for the mechanics of how much boost, what rpm, compression ratio, how much gain in Hp, then you need a technical book which should be readily available on any bookstore.

 

On a vaguely related note...

Could you overcome the problems with turbo lag during acceleration by the judicious addition of compressed air to maintain a proper fuel / air ratio while the turbo is trying to catch up?

I'm thinking of this in the context of locomotive engines mostly, and especially the old ALCOs which had a tendency to lay down a smokescreen while accelerating.

 

If the turbo is matched properly to the engine and the "plumbing" reasonable, there will be little, if any, "turbo-lag". After fabricating a system myself on a four cylinder car, I found this to be the case.

-Tom

 

The lag is not 100% of the problem its the govener that doesnt know there is no boost so it fuels the engine assuming there is.
Many later turbo engines ( not sure about EMD's) had an anerometer on the govener to limit the fuel till the boost pushed a diaphram and enabled full fuel.
Electronic engines of course have this nailed.

80's turbo rally cars had a pressurised bottle to momentarily blast onto the compressor to make instant boost and speed up the turbine.
You still see this on Pikes Peak cars

Turbo's in F1 was what pushed the EFI to the forefront as it was the only way they could control the engines.

Ship engines turbo's have a whole set of their own issues from exhaust deposits you have a wash off to surging/hunting due to their size. They measure the inlet size in feet not inches

 

You need to add a huge variable speed alternator/generator to power something...I guess that wont be aircon up your way?

 

Turbo lag is caused by the delay of the turbo to spool up quickly. In high performance engine whose throtlte is responsive enough, two or several small turbo with low mass are installed. I have read an article of a Ferrari Testarrosa modified by installing four small turbos.

On some, the turbos are cascaded. One low mass first which starts spooling sooner and a big one after to take care of high end boost. These are aftermarket units.

 

"80's turbo rally cars had a pressurised bottle to momentarily blast onto the compressor to make instant boost and speed up the turbine.
You still see this on Pikes Peak cars"

Powerabout, my turbo installation was on an 80's rally car, it had zero, perceivable "turbo-lag" and no pressurized air bottle. Once again, if sized correctly, one may eliminate "turbo-lag" unless you have excessive plumbing (tubing, air spaces) of large diameter. My little 1600 cc motor never developed any power below 2000 rpm anyway but when I would open the throttle the boost gauge would jump from vacuum to boost instantly showing the turbine was already spooled up. I was shocked the first time I observed this.

For cars and trucks, I think turbos are absolutely brilliant. Performance when you need/want it and all the attributes of a naturally aspirated engine when you don't. You can even have low compression ratios if you like for easy starting.

-Tom

 

Turbocharging is a proven way in marine applications decades longer than in cars.

The bigger iron chunks in our business have turbos installed NOT for higher power output, but for better fuel economy. A fully laden combustion process is just a better one in terms of fuel efficiency. And that makes clear, why a 80 litre displacement engine, weighing 8 tonnes, produces only 400 hp, but has a turbocharger! At 440hp it even has a aftercooler. The specific break Hp consumption comes down below 190 g/kW/hr, thats it.

Regards
Richard

 

I don't give a rat's tail about lag. Dosn't seem to be a legitimate part of the marine power agenda. But how is the Yanmar 175hp marine engine going to respond to continuous underloading. Everyone agree w FAST FRED?

Easy

 

But how is the Yanmar 175hp marine engine going to respond to continuous underloading?

No engine likes underloading so the question is , Is an automotive transplant going to suffer at close to normal car /truck loads ?

I think not .

Today Yanmar uses BMW transplants at 400+ hp "auto ratings" , while the base engine gets 40 mpg in a sleek car. No problem,

Just don't stick one in a 60 ft push boat and expect to operate at 350HP for very long.

FF

 

Don't need to know about trucks and cars. Just want to find out how a turbo
will effect the ability of a marine diesel to run at low loading. Like a Nordic Tug running at 7 knots w a run-of-the-mill turbo or (viewed separately) an after-cooled turbo.

 

I'm not an expert on turbo's, but have one on a 220 Cummins engine.

My opinion in a word, No,

I operated my engine for a few years before finding out the phyrometer (sp ?) did work. I had never put the engine under enough load for long enough to bring the heat indicator needle (for the turbo) off the peg.

The turbo is driven by high volume hot exhaust and only when the resistance (force ?) of the compressor blades exceed the mass air flow being pulled by the pistons, will you start to see an increase in power and heat of the unit, it is pretty much just freewheeling between exhaust pressure and manifold vacuum.
I think of it like a torque convertor using air instead of transmission fluid.

My thought is, there should be no real serious negative effect on the engine.

Ron