TechASSIST: Fuel Vaporizers

Fuel Vaporizer DPF Light Issues

So what are Fuel Vaporizers?

The Fuel Vaporizer is a relatively new component designed to improve the DPF regeneration process and further reduce harmful emissions.

DPF regeneration requires extremely high temperatures for soot to be removed from the DPF by combustion. When normal driving conditions do not allow for this temperature to be reached in the exhaust system additional processes must be introduced to raise the heat.

Traditionally, post injection of unburned diesel fuel into the combustion chamber provides the catalyst and raises temperatures. However, this has been found to cause oil dilution leading to premature engine wear or more frequent servicing.

Fuel Vaporizers go some way to solving this problem, lowering emissions whilst prolonging engine life. Rather than being injected directly into the combustion chamber, fuel is directed to the Fuel Vaporizer. The Vaporizer then uses an integrated, electrically heated glow plug to evaporate the fuel before injecting it into the exhaust gas stream ahead of the catalytic converter/ diesel oxidation catalyst. Vaporized hydrocarbons are then burnt on the catalytic converter, releasing energy from exothermal chemical reactions and raising the temperature before the DPF allowing for regeneration to occur without oil dilution or the need for additional cooling.

Fuel Vaporiser Diagram

With the introduction of Fuel Vaporizers, vehicles can achieve more frequent DPF regeneration under lower loads and even at idle.

Fuel Vaporizers commonly feature on Ford passenger and commercial vehicles and whilst the technology boasts improved engine life and reliability, it is believed that many Ford DPF issues stem directly from the failure of this part. As such the demand for the component within the automotive aftermarket is on an upward trend that is predicted to continue over the coming years.

Symptoms of Fuel Vaporizer failure.

When the fuel vaporizer fails, DPF regeneration cannot occur. This will cause the engine management light or engine service message to appear. Fault codes will usually point to a DPF issue.

The vehicle may enter limp home or limited power mode until the fault is rectified.

Common fault codes for the Ford Mondeo which is highly prone to Fuel Vaporizer failure are as follows:

P246B-00: Vehicle Conditions Incorrect for Diesel Particulate Filer Regeneration.
P2463-00: Diesel Particulate Filter – Soot Accumulation.
P24A4-00: Diesel Particulate Filter Restriction – Soot Accumulation Too High (Bank 1)

Causes of Fuel Vaporizer failure.

The most common cause of fuel vaporizer failure is clogging. When the outlet nozzle becomes clogged with soot the component will fail. Cleaning the nozzle is generally not possible so replacement is required.

Overheating can also cause failure; this is usually caused by a lack of fuel being supplied to the component and can point to problems with the fuel pump.

If the glow plug inside of the vaporizer fails, fuel will not be vaporized before entering the process. This may result in dark smoke from the exhaust.

After replacing the component fault codes can be cleared and DPF regeneration can be initiated once the engine reaches the required temperature.