Delphi has developed a new type of oil condition sensor for diesel engines that can help improve engine reliability and reduce costs. The sensors are mainly used on commercial vehicles to detect the oil quality, and having a sensor that can accurately determine the condition can help increase oil change intervals when possible. This obviously can cut costs by reducing the out-of-service time and the amount of oil used.

Current production sensors measure the oil viscosity and dielectric constant of the lubricant. Delphi's new sensors also add in measurements of fuel dilution and soot in the oil, which are caused by fuel and exhaust slipping past the piston rings. The newly designed sensors are highly integrated and are being made available to manufacturers now for new development programs. The full press release is after the jump.

[Source: Delphi]
Delphi Launches New Technology for Diesel Oil Condition Sensing

A new type of oil condition sensor for diesel engines will substantially increase service intervals, help increase engine reliability, reduce warranty issues and bring further cost reductions for vehicle operators

LUXEMBOURG -- A new type of diesel oil condition sensor, developed by Delphi Corporation (PINKSHEETS: DPHIQ), will help increase engine reliability, reduce warranty issues and bring further cost reductions for vehicle operators.

Compared with today's diesel oil sensing technologies, the Delphi system will further extend oil and filter change intervals, reduce the quantity of oil for disposal and help maximise the time vehicles spend on the road.

The new system is now available for integration with vehicle development programs.

Current production technologies measure the viscosity and dialectric constant of the oil, providing useful data from which an estimation of oil condition can be made. These technologies allow a significant increase in change intervals compared with the older predictive techniques that estimate condition based on the drive cycle.

Delphi's technology takes a further substantial step forward by providing additional information that will allow a much more accurate calculation of oil quality.

"The problem with measuring only two variables is that there are many interactions between oil characteristics that can not be extrapolated from this basic data," said Delphi advanced engineering manager Francisco Sanchez. "The measurements of viscosity and dialetric are effectively just an average of many interactions that affect these two parameters. To really understand oil quality, the system needs more data."

To illustrate the requirement for additional parameters, Sanchez points to the increasing need to monitor fuel dilution and soot content. The growing use of multiple post-injection events is leading to increasing amounts of fuel escaping past the piston rings, which reduces lubricity and decreases viscosity. A build up of soot, which reduces the effectiveness of additives and is a growing issue with increasing levels of EGR (exhaust gas recirculation), will increase viscosity. The measured viscosity will therefore be a combination of these two effects and not reflect the true degradation in oil quality.

Delphi's solution is to develop new, highly-integrated techniques for measuring soot and fuel dilution alongside viscosity and dialectric. The same sensor can also measure oil temperature and level and is supplied in a compact package that can be engineered for pan or engine applications.

Fuel dilution is measured by a confidential modification to the proven viscosity measurement system, allowing low-cost and compact implementation of the additional sensing system. Soot is a carbon particle so can be detected by measuring changes in electrical conductivity. Delphi measures AC conductivity at 2-5MHz. The same sensor is also used to measure dialectric.

Existing production technologies measure viscosity by correlating it against a measured shear strength value. Delphi's unique solution is to measure the convection time of the oil when heated by a known amount.

"This is an incredibly elegant solution with a direct correlation to viscosity. We are getting amazingly accurate results, irrespective of oil type, soot content and other contamination," said Sanchez.

When the oil is changed, the sensor detects the step in parameter values and automatically resets. There is no re-calibration required if different oil types are used and no interaction is required from the service technician.

"This is a great example of Delphi's ability to use a clever yet simple design to provide substantial benefits to the vehicle buyers," said Guy Hachey, president, Delphi Powertrain Systems division. "Our new Oil Condition Sensor for diesel will add value for our customers, helping them to gain a real advantage in an increasingly competitive market."

The new sensor will enter production in 2009 for an undisclosed truck customer.

Delphi is also discussing future programs with the military (transporting oil to field operations is a significant logistics cost) and with manufacturers of engines for off-highway applications. The sensor can also be used on light-duty diesel engines such as those fitted to many passenger cars.

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