Project: Detection of Lubricating Oil Burning in Vehicles Fitted with 3-way Catalyst

Reference: S361D/VB

Last update: 23/01/2004 14:47:33


This project will determine the effect of burning excessive quantities of engine lubricating oil on the performance of the emission control system of a Three Way Catalytic converter (TWC) equipped vehicle. If burning excessive lubricating oil renders the emission control system ineffective it may negate the expected cleaner emission benefits.

The project objectives are to:
* test and establish if there is visible blue smoke from a TWC equipped petrol vehicle when it is burning excessive lubricating oil;
* determine the effect of excessive lubricating oil burning on the efficiency and life of the catalyst;
* consider appropriate test procedures and instrumentation and recommend an in-service test for detection of lubricating oil burning in vehicles fitted with three-way catalytic converters;
* demonstrate the equipment and consider the cost and benefits of introducing such a test as an MOT test requirement.


This work extends a previous project. The original work aimed to assess the feasibility of introducing an annual test (MOT) requirement for cars and light vans to limit the emission of blue smoke resulting from burning of lubricating oil. It was not possible to include cars with Three Way Catalytic converters (TWC's) due to an insufficient number of high mileage examples being available when the project began. The number of in-service catalyst cars is increasing and this made suitable project vehicles available. The second phase was to address the practical problems of including such a test requirement in the MOT test for catalyst equipped cars.


AEA Technology Environment
Harwell Business Centre, Didcot, Oxfordshire, OX11 0QJ
+44 (0)1235 432201

Contract details

Cost to the Department: £100,290.00

Actual start date: 01 December 1998

Actual completion date: 31 March 2000


Detection of Lubricating Oil Burning in Vehicles Fitted with Three Way Catalysts
Author: AEA Technology Plc
Publication date: 01/03/2000
Source: Contact

Summary of results

  1. Oil burning does not appear to give rise to visible smoke in Three Way Catalyst (TWC) equipped petrol vehicles. Thus, smoke is unlikely to form the basis of a satisfactory in-service inspection technique for detecting oil burning.

    The effect of oil burning on fine particulates was an increase in both number and mass, although the presence of a TWC reduced tail pipe emissions by a relatively small amount.

    The conclusions suggest that non-regulatory ultra-fine particulate emissions are significantly increased by oil burning, which would not be revealed by current smoke indicators.