→ Injector nozzle tips swell and blow off, why?
The first problem with modern day engines is that if the injectors do not seat correctly in the cylinder head combustion gases escape pass the side of the injector. The ECU picks up a problem with the running of the engine and then tries to compensate by sending more fuel to the offending cylinders thus causing a "over fuelling" situation which in-turn causes excessive heat thus weakening the nozzle. This is evident by noticing one of the copper washers disfigured and "melting" up the injector.
Another problem is the possibility of water in the fuel as this is another reason why nozzle tips "blow" off, have a look at this article "Diesel Fuel, Air Vapors And Your Engine Part 1 of 4 By Steve Pollock"
A quote out of article is,
"Probably the most damaging area affected by entrained air/vapors is the engine's fuel injectors. One of the functions of diesel fuel is to lubricate the injectors as they are working. As the entrained air/vapor passes through the
injector it is not providing complete lubricity.
This lack of lubrication for the injector's barrel ad plunger becomes even more critical with the tight tolerances and high fuel pressures used in today's injectors. The entrained air/vapor creates a metal on metal situation. Over time the plunger can start to stick and as it wears, factory tolerances are lost. This causes fuel blow- by in the injector. According to Caterpillar's handbook, entrained air/vapor can create up to 50% greater forces by the plunger on the injector tip. As the fuel comes out the injector tip under high pressure the entrained air/vapor can also act much like an acetylene torch, eroding the injector tip. These two things in combination can lead to the injector tip breaking off."
→ Stuck Bosch Common Rail Injector, how do I remove it?
Instructions to remove Bosch Common Rail injectors fitted to a Mercedes.
→ Blow-by or the Black Death, what is it all about?
Injector "blow-by" can be the cause of some of the following symptoms.
- Hard or difficult starting
- Erratic or uneven tick over or idle
- Lumpy running
- Smoke on tick over or acceleration
- Black tar around the injectors and a chuffing sound from the engine when running
Injector blow-by occurs when the injector does not seal against the injector seat in the cylinder head. Often a chuffing sound is heard or black "tar" can be seen around the injectors. The engine could also experience one or more of the above symptoms. On some engine applications if this continues serious engine damage could result due to the fact that the ECU will over compensate the fuelling on the cylinder or cylinders with the seating problem causing piston washing or cylinder over fuelling. Even if the injector is removed, cleaned, a new copper washer fitted and then replaced it will not always rectify the problem as the escaping combustion gases may have eroded the seat in the cylinder head. The seat in the cylinder head will need to be refaced with a seat-cutting tool.
→ Can a diesel engine run on fuel other than diesel?
EN 590 DIESEL-SURE TEST KIT Patent pending
The short answer to this question is yes. A diesel engine burns fuel without a spark by injecting an exact amount of fuel into a cylinder containing air that is made hot enough to burn the fuel by compression alone. Hence diesel engines fall into the family of compression ignition engines as apposed to spark ignition engines. Provided the fuel will burn at the temperature created by compression, the engine will run. History shows that diesel engines have been manipulated to run on a variety of substances including sunflower oil, coconut oil, cottonseed oil, buttermilk, turpentine and paraffin. Nevertheless, these products may cause harmful long-term effects including the formation of carbon deposits and excessive wear, leading to eventual failure of fuel injection system.
→ Can the EN 590 DIESEL-SURE test guarantee that the fuel contains no paraffin or heating oil?
EN 590 DIESEL-SURE TEST KIT Patent pending
No. The EN 590 DIESEL-SURE test is designed to identify fuel that does not conform to the current European Standard EN 590 for diesel fuel. Refineries throughout the world do cut diesel with small proportions of paraffin to improve winter flow properties. However, the product sold as diesel must still conform to specification.
→ DPF Cleaning, which method is best?
See the attached document showing the comparison between our DPF Flash Cleaner Machine on the other most common DPF cleaning methods.
Our technology is different from any other on the market because it allows us to clean all kinds of Particulate Filters and Selective Catalytic Reduction units (SCR) used in cars (Euro 6 included), buses, trucks, plant and agricultural equipment.
We don’t cut the filter, bake and weld it. We don’t dip it into a ultrasonic cleaning tank and then oven bake it to dry. United Diesel employs the Flash Cleaning Machine with its Organic Absorbent Emulsifier, flushing the filter both ways and then air drying it.
We are able to monitor back-pressure (mbar) and air flow (m3/h) before, during and after the cleaning process. A printed report then shows a comparison of the initial and final parameters in order to verify the quality of the cleaning.
→ DPF Filters, what are they and what do they do?
What is a DPF (Diesel Particulate Filter)?
A DPF is a filter fitted to modern diesel engines designed to remove particular matter or soot from the exhaust gases of diesel engines so that they are not released into the atmosphere. Please see the attached document.
→ E.G.R. (Exhaust Gas Recycling) units, what do they actually do?
How an EGR (Exhaust Gas Recycling valve) works - in layman's terms
I am sure that if I asked 100 diesel vehicle owners in the street if they knew what an EGR valve was, let alone how it works, a significant majority would not. You might find this interesting or even scary but I hope to explain how it works.
In a diesel engine clean air is drawn through the air inlet by the help of the compressor inlet of the turbo charger (want to know more about the workings of a turbo see here)
The inlet air, warmed by the turbo system during uptake, will cause the carbon dioxide (CO2) molecules to expand and therefor cause a imbalance with the air to fuel ratio but it is then passed through the charge air cooler (also called a intercooler) which then cools the inlet air. Cooling the air therefore will increase the molecules thus allowing for more clean air to burn.
The clean cooled air then enters the cylinder via the inlet valves. When the inlet valves closes the piston then compresses the trapped air and causes the air molecules to expand resulting in a cylinder temperature of over 400°C. Atomized fuel is then injected and combustion takes place which is the explosion known as the power stroke (want to know more see here).
The exhaust valve opens allowing the burnt gases to be forced through the turbo outlet to the exhaust. Flow of the exhaust gases causes the turbo to spin. The spinning of the turbo draws clean air into the compressor inlet of the turbo.
This sounds good because this maintains two individual passages for different airflows; the clean inlet air passage and the dirty exhaust for burnt gasses.
However there is a problem because although the engine runs efficiently, it also produces more Nitrogen oxide (NOx) gases that are harmful to the ozone layer and are a known greenhouse gas.
As a result of this the engine manufactures have thought of a way to reduce the NOx emissions by reducing the oxygen levels in the cylinder, when efficient fuel combustion is not required, i.e. when the vehicle is idling or at low rpm.
This led to the birth of the EGR valve. Here dirty, used, warm air is redirected into the clean inlet of the cylinder from the exhaust. This results in less oxygen being drawn into the cylinder, reducing the combustion temperature and resulting in less NOx emissions.
The down side is that the EGR valve and the cylinder inlet valves get heavily coated in carbon deposits either causing EGR failure or a reduction in the amount of quality clean air being drawn into the engine. This creates an incorrect air to fuel ratio which results in black exhaust smoke, poor running and increased fuel consumption.
Another problem with increased carbon emissions is that it has an effect on the diesel particulate filter (DPF), which is something else that has been developed to help reduce emissions from the exhaust. I will discuss that later.
Below is a picture of an inlet manifold that to be efficient would be clean and free of carbon deposits. However over a period of time the EGR valve has allowed burnt gasses and carbon to enter the inlet manifold thus restricting the ports. This would cause an imbalance in the air to fuel ratio resulting in poor fuel consumption and more carbon to be drawn back in to the inlet via the EGR valve.
→ EGR (Exhaust Gas Recycling valve) how it works - in layman's terms
I am sure that if I did a pole of 100 diesel vehicle owners in the street and asked them if they knew what an EGR valve was let alone how it works, I am sure that there would be a higher percentage that does not know. You might find this interesting or even scary but I hope to explain how it works. I have copied a diagram off Google images to help with the explanation.
Clean air is drawn into the air intake through the air filter via the inlet housing of the turbo charger (want to know more about the workings of a turbo see here – link)
As the air has now been warmed by the turbo and the co2 molecules have expanded it is necessary to try and cool the air as the cooler the air the as more reduced co2 molecules result in a better air to fuel ratio. The warm air then passes through the inter cooler which cools the air.
The nice clean air then enters the cylinder via the inlet valves and once the valves close the piston compress the trapped air and then when the injector injects combustion takes place (want to know more see here – link)
The burnt air then passed the exhaust valve and pushes down the exhaust manifold past the turbo, spinning it to help drawn in clean air into the inlet side, then out of the exhaust.
Sounds good because this way the inlet passages to the cylinder are kept clean to allow nice clean air in and the exhaust allows for the burnt gasses to go out.
Problem, because this way the engine runs efficient but also produces more Nox gases, harmful to the ozone layer as it is a greenhouse gas.
So the engine manufactures have thought of a way to reduce the Nox, that is to reduce the oxygen levels in the cylinder when the vehicle does not need to be efficient like at idle and at lower revs.
The birth of the EGR valve. Dirty, used, warm air is redirected into the clean inlet of the cylinder from the exhaust. By doing this less oxygen is drawn into the cylinder thus reducing the combustion temperature resulting in less Nox emissions.
The down side is that the EGR valve and inlet valves get totally carboned up thus resulting in EGR failure and also a reduction of clean air being drawn into the engine resulting in a incorrect air to fuel ratio which cause black smoke, poor running and increased fuel consumption.
Another problem with increased carbon emissions is that it has an effect of the DPF (diesel particulate filter), which is something else that has been developed to help reduce emissions from the exhaust. I will discuss that later.
Below is a picture of a inlet manifold that to be efficient would be totally clean but over a period of time the EGR valve has allowed burnt gasses and carbon to enter the inlet manifold thus restricting the ports. This would cause an imbalance to the air to fuel ratio resulting in poor fuel consumption and more carbon to be drawn back in to the inlet via the EGR valve.
→ How different do TDI VE Injectors flow?
This is the test results of various nozzle flow rates showing the differance in deliverd quantity.
This has been done useing the most accurate testing method as all nozzles were tested useing the same "on engine" paramiters.
Please note that this information remains the property of United Diesel Fuel Injection Services Ltd.
→ How do I cancel my contract and return my goods?
Cancellations – Under the Consumer Contracts Regulations 2013, you have a right to cancel within 14 days of receiving your goods. To arrange cancellation, please download and complete our cancellation form and return the completed form to us within 14 days of purchase, with proof of your order.