How Diesel Engine Turbochargers Work

How Diesel Engine Turbochargers Work

Mechanic Notes:  A diesel engine is 'dead in the water' without the turbocharger. High pressure atomized diesel injection needs maximum air intake boost to operate efficiently. You'll know when the turbo is not working up to speed, the smoke show out the tail pipe will be the obvious sign.

 Mechanic Checks for A Turbocharger Problem
If you suspect a turbocharger problem and the diesel engine you're working on is a mechanical model you can check the boost pressure which should be around 20 p.s.i.

Take the reading off of the intake manifold with the engine at full throttle and full load. Hook up a line and go for a road test and make sure you get a nice heavy pull on the engine. The next step is to remove the intake side of the turbo (easier than the exhaust side) and check the compressor wheel and shaft for any movement and wear or signs of engine oil in the piping.

The air induction system includes the air filter and piping which must not be overlooked. Simple steps include checking for a restriction in the air filter and visually checking out the piping for loose clamps and perforations. The first sign of a hole in the piping or a loose clamp will be a high pitched whistle, not to be confused with the characteristic whine that comes from a turbocharger under load.

 This is a common problem and can be checked by setting the park brake (set wheel chocks as an extra precaution), foot brake on, transmission in gear and throttling up the engine RPM enough to feel a load. You'll need assistance with this test so you can look and feel for leaks.

Electronically controlled diesel engines will most likely flash a trouble code on the dash which requires diagnosis with a laptop / software. The modern day Mechanic needs software and a laptop...if you don't have these tools you're going to go down fighting.

Here's an excellent video tutorial on how the turbocharger works. Check it out!

Biggest Diesel Engine In The World!

Here is a diesel engine that you can really sink your teeth into. It's built in Japan and my jaw dropped when I first saw this mega machine! I'm thinking about what the machining tools look like that built this thing?

The fuel costs amaze me (data below) and being a 2 stroke...how loud is this engine and what do the higher rpms do to the life of the engine?

PISTON AND CONNECTING ROD



ENGINE BLOCK



The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today. The Aioi Works of Japan's Diesel United, Ltd built the first engines and is where some of these pictures were taken.

It is available in 6 through 14 cylinder versions, all are inline engines. These engines were designed primarily for very large container ships. Ship owners like a single engine/single propeller design and the new generation of larger container ships needed a bigger engine to propel them.

The cylinder bore is just under 38" and the stroke is just over 98". Each cylinder displaces 111,143 cubic inches (1820 liters) and produces 7780 horsepower. Total displacement comes out to 1,556,002 cubic inches (25,480 liters) for the fourteen cylinder version.

Some facts on the 14 cylinder version:
Total engine weight: 2300 tons (The crankshaft alone weighs 300 tons.)
Length: 89 feet
Height: 44 feet
Maximum power: 108,920 hp at 102 rpm
Maximum torque: 5,608,312 lb/ft at 102rpm

Fuel consumption at maximum power is 0.278 lbs per hp per hour (Brake Specific Fuel Consumption). Fuel consumption at maximum economy is 0.260 lbs/hp/hour. At maximum economy the engine exceeds 50% thermal efficiency. That is, more than 50% of the energy in the fuel in converted to motion.

For comparison, most automotive and small aircraft engines have BSFC figures in the 0.40-0.60 lbs/hp/hr range and 25-30% thermal efficiency range.

Even at its most efficient power setting, the big 14 consumes 1,660 gallons of heavy fuel oil per hour.

This an amazing diesel engine and I wonder if they will ever go hybrid? Just Kidding...I don't think they would room for the battery pack. It would be one heck of an accomplishment. Japanese technology reigns supreme once again. It makes me wonder why they can build these huge machines in their own country and HOW A CRUISE LINE run them without going broke with the fuel costs & diesel engine maintenance. I would guess ticket sales would have to be adjusted UP (most times) in accordance with the price of fuel.

Here is an excellent video explaining how a 2 stroke Gas Engine works the principle being the same with diesel engines.



Check out this Detroit 8V 71 2 Stroke Diesel Running (Takes me back to the non emmission control days...where there's smoke there's a screamin' Jimmy!). Having 2 strokes instead of 4 makes it easy to understand how much higher the RPMs are. If I were these guys I would have rigged up a decent engine stand.



The Wartsila-Sulzer RTA96-C Homepage DIESEL ENGINE

Diesel & Gasoline Working Together?

The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine pictured has a thermal efficiency of 50% (the best in the world). There is new research going on in the University of Wisconsin, Madison that got 53% thermal efficiency out of a Cat Diesel Engine.

I just read the article about this new technology mixing gasoline and diesel into a diesel engine. This system increases the thermal efficiency by 20% but reduces the temperature in the combustion chamber by 40% creating less unburned fuel out the tail pipe.

The mix would be computer controlled and since there would be less energy loss through heat transfer, improved combustion would cause an increase in power with less emissions.

The computer age has allowed scientists and researchers to stretch the resources we have right now to the limit in a very efficient way. Without computer programming, monitoring, and adjusting operating parameters this new technical solution for decreasing vehicle emissions would not be possible.
I hope you found this Mechanic Information interesting...

New Study Heavy Duty Diesel Emissions Reduced Drastically-New York Times

I'm Guessing The Next Study Will Be Lowering Emissions On Super Duty Diesels like the one ABOVE!

Here's an interesting article on a 5 year study by several Environmental Groups including the Health Effects Institute, Coordinating Research Council, Energy Dept., EPA, Engine Manufacturers Association and the American Petroleum Institute.

Read The Full Article HERE

Researchers have found particulate matter called soot has been reduced by 99% from levels allowed in 2004. Emissions are also 90% lower than 2007 standard requirements. Good news for us and the air that keeps us alive!

Right now the new DPF (diesel particulate filter) mufflers are collecting soot and burning it off into the atmosphere automatically by way of computer technology. The DPF has sensors that tell the computer the temperature is getting excessive on one end and needs to start a regeneration.

Regeneration is computer activated which injects atomized diesel into the exhaust system burning off accumulated soot. If the soot buildup gets too much to handle, a manual regeneration is required using laptop software.

This manual regeneration takes about 45 minutes and the temperatures get at high as 1200 degrees. This is a very efficient way to burn off particulates/soot. Every Mechanic involved with today's diesel engines will be repairing and maintaining these emission controlled systems for many years to come.

Diesel Engine Troubleshooting

Today's diesel engine troubleshooting procedures have changed since the introduction to computers and higher fuel emission standards.

A laptop is a necessity and software is rampant among all the major diesel engine manufacturers. There is still things you can do to overcome the electronic learning curve a lot of technicians have trouble with.

If I were to think of the best advice to give someone embarking on a diesel engine troubleshooting scenario, it would be one thing.
That one thing is "always check the source".

Don't go to the injectors or valves unless you hear a noise of some sort. If there's mechanical noise coming from the crankcase then you're going to pull the valve cover and inspect the top end. Then you need to drain the oil and pull the oil pan looking for scored cylinders or tidbits/chunks of metal.

For a no start always check the fuel tank. This sounds so easy but it's happened caused embarassing moments. The tank gets overlooked and parts get replaced for no reason because of a cracked or rubbed through fuel line coming out of the tank.

Start at the pressure side [after the second fuel filter or fuel pump] of the fuel system and start cracking lines open. If you've got fuel keep going forward if not go backwards checking for fuel.

If the engine runs and craps out after a minute or so check for air in the system caused by a cracked or rubbed through fuel line. Run the fuel line into a bucket of fuel and see if that makes a difference. If so, start going backwards from there. Hook up a clear line to the return fuel line and check for air that way.

This isn't the technical way of diesel engine troubleshooting but it has worked for me many times finding some really goofy problems that are easily resolved. So check the simple things first and don't get too wrapped up in the high tech side of the engine until you're sure you've covered these basics.

Advantages of LPG and CNG in Diesel Engines

The vast majority of diesel engines in service today use solid injection and the information below relates to that system. In the diesel engine, only air is introduced into the combustion chamber.

The air is then compressed to about 600 pounds per square inch (psi), compared to about 200 psi in the gasoline engine. This high compression heats the air to about 1000 degrees Fahrenheit. At this moment, fuel is injected directly into the compressed air.

The fuel is ignited by the heat, causing a rapid expansion of gases that drive the piston downward, supplying power to the crankshaft. In Diesel's manuals, he described the supply of compressed gas into the cylinder to promote the final burn. It is now possible to fumigate the air intake with a small quantity of LPG/CNG.

The now air-gas mixture is compressed as above, and when the diesel ignites, the small quantity of gas ignites as well, causing a more rapid and more complete burn of the diesel. Most diesel engines waste between 30 and 15% of the diesel fuel, so by burning the near total amount of diesel consumed on each stroke, the mechanical effect is to improve the torque curve by as much as 28%.

The net outcome of applying gas into diesel is improved fuel economy via better torque at the driving wheels resulting in fewer gear changes, and greatly reduced exhaust emissions.

Advantages of the diesel engine are numerous. It burns considerably less fuel than a gasoline engine performing the same work. It has no ignition system to attend to. It can deliver much more of its rated horsepower on a continuous basis than can a gasoline engine. The life of a diesel engine is generally longer than a gasoline engine. Although diesel fuel will burn in open air, it will not explode unless compressed.

Some disadvantages to diesel engines are that they are very heavy for the horsepower they produce due to the required heavy design, and their initial cost is much higher than a comparable gasoline engine.

Recommended: Diesel Engine Repair Manuals

Cat 3116 Engine Installation-Thomas Buses

This is a Cat 3116 Engine installation into a Thomas Pusher. This process is much easier with the transmission installed [MD 3000 series]

The transmission jack supports the trans. and the hydraulic crane hooks on nicely to the front engine lifting eye. With some assistance we rolled the whole assembly into the backend with ease. You'll notice the rear subframe and bumper have been removed. This is one great advantage of owning a Thomas pusher although we don't want to be doing this particular operation too often...

Cat 3116 Engine Synchronization Video Tutorial

Cat 3116 Diesel Engine Setting Synchronization is a multi-step operation and requires the Cat Tune up Kit. Some standard hand tools will work but most of the setting tools are specially designed for this purpose. NOTE: Remove fuel solenoid before starting synchronization, this allows free rack movement.

Below is Step One:

Calibrating #1 Injector




Step Two:

Setting Up For Injector Synchronization



Step Three:

How To Adjust Injector Synchronization



This is the hardest step to get around {especially for the first time} but comes much easier with repetition. The Cat 3116 Diesel Engine is a fussy engine to tune up but it pays you back with great performance.

The Biggest Diesel Engine In The World! You Gotta See This..

Believe it or not these are the crankshaft main bearings!

Some facts on the 14 cylinder cyl.
	Total engine weight:	2300 tons
	Length:	89 feet
	Height:	44 feet
	Maximum power:	108,920 hp

Check out the Website here


Here of course is the Crankshaft!
It weighs 300 Tons.

Cummins ISC Electronic Diesel Engine- cranks over but will not run.

Cummins ISC Diesel Engines need to be analyzed using a laptop computer with Cummins Insite software.

Sometimes however you can troubleshoot a no run problem the good old fashioned way by looking listening and using common sense.

The fuel transfer pump mounted on the left rear of the engine is a vane type unit driven by an electric motor.

The first clue was the transfer pump motor was not running at all with the ignition key on, it will charge up the system every time you hit the ignition key with a very distinctive motor noise at high rpms.

So since the golden rule with electrical problems is to check the source I went to the battery and checked the multiple fuses that supply power to the engine ECU [electronic control unit]

I found 3 fuses had blown indicating a possible short or high amp draw. The first thing to do was hook up a jumper wire [with an inline breaker in case there was a short]

Once hooked up the fuel transfer pump started working but sounded very sickly! It was enough to limp the School Bus back to the shop.

Since the main problem was a overly high draw from a faulty fuel
pump motor, replacing the fuel transfer pump was our next step.

The fuel pump must be installed as a unit [do not just change pump and motor] and will not seal properly on the old housing. You are guaranteed to have a fuel leak once you start it up.

How do I know? because I tried it as a shortcut and instantly had a fuel leak between the housing and fuel pump/electric motor.

There is very little room to move in this Thomas pusher since it is a rear engine unit. Remove power steering lines and rear radiator frame brace to gain access to the pump housing fuel lines and mounting bolts.

Test the pump by cycling it a few times with the ignition switch.

Fuel filter replacement is recommended, we pre-fill the primary filter and install the secondary filter dry which allows incoming fuel to be pre-filtered instead of being poured out of a fuel container, this avoids contamination.

The new fuel transfer pump will do all the work priming the system.

Just listening to the uncharacteristic sound of the fuel transfer pump led us to this rather easy diagnosis. It's a gimme that doesn't happen too often.

The main tip here is to always check the source first when troubleshooting a problem. Electronic diesel engines like this Cummins ISC model still run off a 12 volt battery so things have not changed too much from a few decades ago!

School Bus Mechanic on my "Squidoo" Lens

Cat 3116 Diesel Engine Installation into a Thomas School Bus

Thomas School Bus Diesel Engine Installation: This engine was rebuilt in our shop because of a wayward exhaust valve seat that didn't want to stay in one piece. So consequently everything from the head down had to be rebuilt.

Step one:
Tow in dead School Bus.
We will utilize our shop made tow bar that has been around for a couple of decades, but still does the job.

It may still make it to the "Smithsonian Institute"



The Bus made it into the shop and is now waiting for some Diesel Power to give it life once again.







Mounting "Allison New World" Transmission to engine flywheel housing and flexplate [much easier on the floor!]







Engine and transmission are together now [the transmission is supported by the trans. jack]
The entire assembly will be installed together.






The bumper and frame support were removed previously which makes the installation job much easier!
The complete engine and trans. assembly slid into place nicely.






The engine is resting on the front and rear engine mounts. Now comes the fussy part connecting wiring, hoses and accessories.







Tow bar installer obviously having a good time!








Once the bus to be towed is aired up it's easily manuevered into the shop with two operators.








Having lots of space to work is always a bonus! I will post more pictures as the job progresses.
The final picture will be smoke coming out the tailpipe....

That's basically all there is to it when installing a diesel engine/transmission into a Thomas School Bus.

Watch This Project On Video Put Together With Still Pictures

Cummins Diesel Engine Turbo Failure

Cummins Diesel 'C' Models come with a Holset brand Turbocharger. The operator noticed a noise coming for the engine, it was the turbocharger compressor and turbine wheels making contact with the turbo housing.

When a turbocharger fails it's hard to guess how much damage has occurred and how much debris has gone through the system.
In this case on one of our "C" Cummins Engines the turbo shaft bearings failed and the oil which is fed from the engine under pressure entered the exhaust and intake system.





Once you get oil in the system and various particulates or even chunks from the failed turbocharger it is recommended to replace the air charge cooler as well.
This one was saturated with engine oil, we always have a rebuilt air charge cooler on hand since there has been problems with the aluminum core deteriorating causing turbo boost leakage and loss of power.

The turbocharger was sent out for repair and all the piping checked and cleaned out as required. This problem was caught in time by the operator who heard the noise from the engine as it happened.
If undetected there would have been much more damage. Once we replaced the turbo and the air charge cooler this bus was ready to go once again.

This is what could happen and most times cannot be avoided on a Cummins Diesel Engine.

Diesel Engine- Basic Principles For Beginners

Diesel engine principles are pretty straight forward for the experienced mechanic but what about regular everyday people who have never taken the time to find out more about a diesel engine and how it works?

I am going to explain in layman's terms the basic principles of a diesel engine. WHAT'S THE DIFFERENCE BETWEEN A GASOLINE ENGINE AND A DIESEL ENGINE?...a quick overview.

The first thing you should know is a gasoline engine and a diesel engine are totally different. A gasoline engine is constructed much lighter than the heavier built diesel engine and runs on an air/fuel mixture combined with a high energy spark that is timed to ignite the air/fuel mixture inside each engine cylinder at the precise time creating power and torque [turning force] which drives your vehicle.

A diesel engine uses high compression [intake air that is compressed / squished] into a very small space inside each cylinder causing extreme heat! This is called 'Heat Of Compression' which ignites a very fine high pressure mist of diesel fuel that is injected into the cylinder at the exact time.

So you now know that a gasoline engine needs a high energy spark to run while a diesel uses 'Heat Of Compression' THE FOUR STROKE PRINCIPLE Every engine today runs on FOUR STROKES or FOUR CYCLES- both these terms mean the same.

Here is how the four stroke diesel engine operates. The four strokes are:

INTAKE-COMPRESSION-POWER-EXHAUST.

The pistons, valves and injectors work together in each cylinder in a set sequence over and over.

1} INTAKE STROKE: Intake valves in the cylinder head open allowing pressurized air to enter each cylinder while the piston is travelling downward.{the pressurized air supply is made possible by the TURBOCHARGER which pushes air into the intake system giving the diesel engine a boost of air to keep up with instantaneous injection of fuel}

2} COMPRESSION STROKE: When the piston starts to make it's way back upward the valves close which traps the intake air in the cylinder which allows compression to take place, the HEAT OF COMPRESSION is reached when the piston reaches the top of the cylinder, the diesel fuel is then injected into the cylinder at the precise time.

3} POWER STROKE: After injection takes place an explosion occurs in the cylinder because of the combination of heat and atomized diesel fuel. This causes the piston to be forced downward which produces torque and the horsepower required from a typical diesel engine.

4} EXHAUST STROKE: After the power stroke the piston moves upward once again while the exhaust valves open allowing the previously ignited gases to escape to the atmosphere out the exhaust system.

As mentioned before each cylinder goes through this exact sequence over and over in a set firing order. For instance, a 6 cylinder diesel engine has a firing order 1- 5- 3- 6- 2- 4 This is the order that each cylinder goes by, following the 4 strokes mentioned above.

This sequence has been engineered to allow the diesel engine to run smoothly with no imbalance.

DIESEL ENGINE TRIVIA: Today's high performance diesel engines. Fuel passes through the injector at speeds of nearly 1500 miles per hour - as fast as a jet plane at top speed. Fuel is injected into the combustion chamber in less than 1.5 milliseconds, the same time it takes for a camera flash to go off.

The minimum amount of fuel injected into a diesel engine is one cubic millimetre - about the same volume as the head of a pin. Volkswagen has developed a 1 litre diesel powered car that got 100 kilometres out of .89 litres of fuel {60 miles on approximately 3/4 of a quart of fuel!}

There is much to learn about diesel engines and a ton of information online. If you have ever considered buying a vehicle with a diesel engine you have my blessing!

The extra cost will be to your benefit, so I recommend finding out more about diesel engines before you decide which one to choose.

I hope you have found this information on diesel engines helpful!