Diesel Performance 360

So what’s the problem with water build-up? Why does it matter? It matters, for the following reasons:

Eventually enough wax floats around in the fuel that the fuel gels up and the wax plugs the fuel filter, shutting off fuel flow and sidelining the vehicle.

It can be clearly show that valve deposit buildup affects the vehicle’s driving performance and it gets worse the more deposits that build up.

This issue is most pronounced in the long-haul trucking industry where vehicles log many hundreds of thousands of miles per year.

And this means poor fuel combustion in the engine, incomplete combustion, formation of deposits, more unburned or partially burned fuel leaving the combustion chamber poor emissions, and less-than-optimal fuel economy because stratified fuel doesn’t give the maximum energy value upon combustion that fresh fuel does.

But in a diesel engine there is no spark, and the engine must turn over many times in order for enough heat to build up and permeate the walls of the cylinder such that auto-ignition of the fuel will happen.

These studies show up to a 15% decrease in city economy and 5% decrease in highway according to EPA test protocols.

IDI tends to be smoother and quieter, while DI is more fuel efficient.

Fuel pumps and injectors both rely on the lubricating compounds naturally found in diesel fuel after distillation at the refinery.

All of these are good enough reasons to control the build-up of water in the tank; this is typically done by using some kind of concentrated fuel treatment.

Spray Patterns of Clogged vs Clear Injectors

MICROBIAL CONTAMINATION

INTRODUCTION

3 – 2.

Consumers who own diesel cars love the outstanding fuel economy.

Both gasoline and diesel fuels consist of components that boil over a wide temperature range the diesel range is higher than the gasoline range.

How do you know if you’ve got an infested tank? You’ll probably notice rough running and poor performance with your vehicle or boat.

INJECTOR DEPOSITS

Humid air flows in and out of the storage tank, and when the air cools at night, the temperature change causes the moisture in the air to condense into the tank.

But even low levels of deposit accumulation can affect mileage and emissions, since the deposit can act as a sponge, absorbing fuel into the pores of the deposit, then releasing the fuel through evaporation or desorbtion release of absorbed fuel.

This is where the devil is in the details.

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Problems with power loss, decreased fuel economy, startability, driveability demerits, decreased power increased acceleration times and increased emissions can all result from this.

EXECUTIVE SUMMARY

BELL PERFORMANCE FUEL ISSUES SERIES: MOST COMMON DIESEL FUEL PROBLEMS

Typically these deposits can build up in the piston bowl area.

As a diesel fuel user, whether truck or boat, you may aware of certain problems that come with the territory.

Their flow characteristics are set to allow a small pilot injection of fuel to initiate combustion, and then inject progressively more fuel into the burning mixture.

Diesel fuels with higher cetane ratings are easier to start in cold weather because more of the different-size molecule combust at the proper time.

Combustion chamber deposits can also act as both insulators and fuel sponges.

Example showing the effect of detergent additives on inlet valve deposits compared to unadditized fuel.

DIESEL FUEL STABILIZATION AND BREAK DOWN OVER TIME

Effect of Deposits on Diesel Injectors

(What most commonly causes or contributes to fuel instability and breakdown? As mentioned before, exposure to water or air can start or speed up fuel oxidation.| Both water and air are excellent oxygen donators, and oxygen is the primary culprit in oxidation.| Exposure to certain kind of metals like copper as the fuel passes through a fuel storage and delivery system – this can also start and speed up oxidation, although these kind of metals merely act like catalysts and oxygen would still need to come from another source not usually an issue in the typical fuel storage system or tank.| Exposure to light, like exposure to metals, is a catalytic contributor, because sunlight This is why diesel fuel poured into a glass jar and left exposed to sunlight will still darken over time – the oxidation reactions cause the color change.

COLD WEATHER PERFORMANCE

Vehicular studies do not show combustion chamber deposits to significantly lower fuel economy; injector and valve deposits have a much greater effect on fuel economy.

Diesel fuel does not burn as cleanly as gasoline does.

CONCLUSION

Under the worst conditions of 30% average flow restriction, with a corresponding range of 30% between the best and worst injectors, the author showed: a 700% increase in hydrocarbon HC emissions

What’s more, you don’t even have to have a storage tank for this to happen – water even builds up in the fuel tanks of long haul trucks.

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COMBUSTION CHAMBER DEPOSITS

INTAKE AND PORT VALVE DEPOSITS

But the chemical processes used to strip the sulfur from the fuel – hydro-treating – drastically reduce the low-sulfur fuel’s ability to lubricate the engine parts that used to depend on such lubrication because it chemically destroys the complex organic molecules that perform the function.

To be sure, diesel does offer advantages over gasoline as a vehicle fuel.

Mechanism of Formation of Injector Deposits in Diesel Engines

The tendency to store diesel fuel leads to potential for oxidative breakdown, build up of harmful water in the storage tank, and microbial infestation of the fuel supply, which necessitates use of a biocide to eliminate the infection.

• As noted below, water allowed to accumulate in a tank increases the chance of a microbial infestation – bacteria and fungi which can play havoc with the fuel system.

LUBRICITY

However, many of today’s diesel fuels give excessive levels of injector coking, disrupting the fuel spray pattern and degrading atomization.

Light really just acts as a catalyst to accelerate oxidation reactions – where oxygen reacts with the fuel molecules and causes them to react with other molecules – fuel or not – leading to the formation of polymers that react with other polymers in chain reactions.

If you live up in cold northern weather, it would be wise to consider this kind of treatment if you have not already.

Therefore it may be useful for the consumer to use an aftermarket fuel treatment to remove these deposits and prevent their formation.

Valve deposits can also be a result from a mixture of environmental contaminants and also from mechanical issues in older engines, where engine blow-by from a worn PCV valve, cylinder blowback from insufficient ring seal and wear, exhaust gas recirculation in large transportation truck engines and lubricating oil, all of those can combine to build up on the valve stems and underside of the valve, forming deposits.

The whole issue of stabilization and storage is a bigger issue for diesel than for gasoline because it is much more common to store diesel fuel for longer periods of time.

WATER BUILD-UP