Continuing just-auto’s series of interviews with tier one suppliers, Matthew Beecham spoke to John Fuerst, Vice President Engineering, Delphi Powertrain Systems about how developments in aftertreatment are affecting the choice of engine management strategy. Delphi Powertrain Systems encompasses gasoline and diesel engine management systems. It also has responsibility for diesel and automotive aftermarket activities and original equipment services.

Following tighter legislation regulating urea quality and quantity, SCR (selective catalytic reduction) systems are an area where we are seeing a need for onboard diagnostics (OBD) and hence the need for new innovative sensor solutions. What is Delphi doing in this respect?

Delphi offers the only exhaust ammonia sensor in the automotive market. The capability of this sensor to directly measure ammonia in the exhaust enhances SCR system diagnostic capability and enables improved closed loop SCR dosing control.

Delphi has also developed an innovative control and diagnostic strategy using a standard NOx sensor, based on a processing of the raw NOx sensor signal. This strategy allows [us] to generate a virtual ammonia signal in most engine operating conditions. The estimation of ammonia concentration is then used in combination with the NOx signal in order to pinpoint any failing component in the SCR system.

What are the issues driving OBD requirements for SCR?

Tighter NOx emissions control legislation is driving a need for increased precision to diagnose SCR system failures at lower threshold levels.

Could you comment on how developments in aftertreatment are affecting the choice of engine management strategy?

More than ever, global mandates for reduced fuel consumption coupled with the need for reduced emissions are driving the development of optimised system-level solutions. Thus, our engine management system activities are constantly balancing engine efficiency improvements with engine emissions and providing the appropriate exhaust conditions (e.g. air-fuel ratio, temperature, etc.) to ensure high performance of the aftertreatment system. Base engine improvements, improved aftertreatment efficiency over a broader temperature range, and improved engine sensing and control all work together to ensure excellent performance while meeting fuel economy and emissions requirements.

To what extent is the electrification of the vehicle driving more actuation as well as new sensor technologies?

Our engine management systems are adapting to accommodate the increased use of electric actuators being implemented to reduce parasitic losses, e.g. electric power steering and water pumps.

Delphi sensors maximise engine and transmission performance by monitoring engine, battery, transmission and fuel parameters such as air/fuel ratios, evaporative emissions, torque and temperature. We are continually developing breakthrough sensing and actuating solutions to help optimise emissions control, fuel economy, and driveability.

Delphi Battery Monitoring Devices offer precise measurement of current (I), voltage (V) and temperature (T) to help improve the overall performance and life of the battery while helping increase fuel economy.

Arc detection sensors will also be needed in the future for high voltage vehicles.

Could you also comment on the ways in which the megatrend for alternative fuelled vehicles is driving innovation in sensors?

The remainder of this interview is available on just-auto's QUBE Global light vehicle OE exhaust & emissions aftertreatment systems – forecasts to 2030