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Small Size, Important Benefits

It may be small, but the diminutive Mini-Switching Oxygen Sensor from Delphi can add big value to a small-engine program.

Electronic fuel injection is gaining in popularity among many manufacturers of motorcycles, scooters, and even lawn and garden equipment and other vehicles powered by one- and two-cylinder engines. As these manufacturers anticipate more stringent emissions legislation worldwide, it is likely more will implement some form of engine management system in the not-too-distant future.

Delphi is positioned to help with its Multec^® Electronic Fuel Injection (EFI) system for small engines. Delphi's Multec EFI system can help deliver enhanced reliability, performance, and fuel economy, as well as reduced emissions. And one of the key components that can help the Multec EFI reach its full potential is the small, lightweight, and self-heating Delphi Mini-Switching Oxygen Sensor.

	Delphi's Mini-Switching Oxygen Sensors offer significant size reduction to enable improved packaging for small gasoline engine applications.

The Delphi Mini-Switching Oxygen Sensor is based on Delphi's proven Switching Oxygen Sensor technology—but in a package that is up to 50 percent smaller and only one-third the weight. Leveraging extensive experience in designing and producing engine management systems for many of the world's leading vehicle manufacturers, Delphi's Mini-Switching Oxygen Sensor offers an easy and convenient way to implement an EFI system. It is suitable for use in both gasoline systems and gasoline-ethanol blended fuel powered applications, which may become increasingly attractive to equipment operators due to the rising cost of fuel.

For many commercial mower operators, the highest expense incurred is fuel. Having machines equipped with Delphi's Mini-Switching Oxygen Sensor, which helps enable the use of several fuels including E85, E100, and gasoline, provides the desired advantage of economic flexibility. When filling up at the pump, an operator can simply choose the fuel with the best value.

"The Delphi Mini-Switching Oxygen Sensor's reduced packaging size and small profile makes it ideal for small-engine applications," noted Scott Nelson, senior project engineer, Mini-Switching Oxygen Sensor. "One perfect example is its suitability for use in motorcycles, as designers appreciate the sensor's weight-saving opportunities in addition to the benefits of closed-loop air-fuel control for improved performance and reduced emissions."

The Same, But Different

Like its larger Delphi Switching Oxygen Sensor cousin, the Mini-Switching Oxygen Sensor provides measurement of the oxygen content in the exhaust to permit engine management system fueling adjustment to maintain stoichiometric operation. This helps assure complete combustion and helps minimize CO, NO_x and HC gases released to the environment. But unlike the larger counterpart, its 12 mm thread size allows the Mini-Switching Oxygen Sensor to be easily installed in a typical small-engine exhaust pipe, where its short insertion and small diameter helps minimize exhaust restriction.

The Delphi Mini-Switching Oxygen Sensor is equipped with a self-heating capability that enhances its accuracy, reliability, and even its durability potential since it does not have to be mounted close to an exhaust port where it can be subjected to extreme and potentially harmful temperature variations.

"The sensor features an integral, low power 0.3 A heater, allowing it to be mounted further downstream than conventional unheated conical sensor technology sensors," said Ivan Samalot, chief engineer, Delphi exhaust sensors. "It is well known that when an oxygen sensor must be mounted close to the exhaust port in order to get the sensor up to operating temperature during light-load conditions, because it is not self-heating, the sensor can be susceptible to biased signals (due to detection of incomplete combustion outflows, especially during cold-start conditions). In contrast, a self-heating capability means the sensor can remain active under all conditions, including extended idles. In designing our Mini-Switching Oxygen Sensor, integrating a self-heating element was a priority in order to allow designers to mount the sensor in a variety of locations without fear of losing optimal control and combustion characteristics."

The Delphi Mini-Switching Oxygen Sensor's alumina/zirconia-based element structure features planar element technology that enables fast light-off (< 12 seconds). That in turn yields high performance—even during initial engine startup—to help minimize cold-start emissions. And while shorter than the conventional-size Switching Oxygen Sensor, the Mini-Switching Oxygen Sensor maintains a high-temperature capability, which means it can be placed in a variety of locations in the exhaust system and still maintain consistent operation. Its mounting flexibility, along with the use of Delphi's industry-leading poison-resistant coating, helps make the Delphi Mini-Switching Oxygen Sensor extremely durable, helping resist thermal shock without cracking. Delphi's patented coatings also help maintain a stable switch point.

"With its reduced energy design, its low power consumption can even help minimize a vehicle's electrical energy requirements," added Samalot.

In addition, Delphi's Mini-Switching Oxygen Sensor offers a pumped air reference and an isolated ground, unlike other switching oxygen sensors. The pumped air reference capability helps prevent air reference contamination from various sources, including grommet, exhaust, and external sources.

Experience to Rely On

While the small size and light weight of the Delphi Mini-Switching Oxygen Sensor are what might initially catch the attention of a small-engine manufacturer focused on packaging constraints, it is the performance backed by years of engine management experience and fuel injection systems expertise that sets Delphi's sensor apart. In addition to offering one of the industry's most complete portfolios of sensors, Delphi boasts a thorough understanding of engine management systems—whether for gasoline or alternative fuel applications.

"The Mini-Switching Oxygen Sensor is truly an innovative engine management technology that can help manufacturers deliver outstanding performance and excellent value," said Phil Boling, marketing manager, Delphi exhaust sensors. "More than 30 years of experience has positioned Delphi as a provider of high-quality, high-value products backed by exceptional support and tailored to manufacturers' individual requirements."

For more information about the Delphi Mini-Switching Oxygen Sensor, click here.