Delphi’s new injection system is the first to provide closed-loop control.
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| Delphi’s latest generation Multec common rail injector begins production in 2004. The system is designed to help automakers comply with the European Union’s Euro IV emissions regulations. |
The new generation Multec common rail system is based on a combination of very fast reacting solenoid valves which enable multiple injection events, increased injection pressure capability, and a new closed-loop control system known as Accelerometer Pilot Control (APC).
Information from the APC allows the engine management system to analyze the quality of combustion so that injection can be adjusted as conditions change, and the system is always correctly calibrated.
As such, the new injection system targets improved engine running chararterstics as well compliance with the Euro IV stage of European Union emissions legislation. It will enter production in 2004.
“We expect to enable car manufacturers to meet Euro IV in a cost effective way via refinements to traditional solenoid valve technology,” notes Jose-Maria Alapont, president, Delphi Europe-Africa-Middle East and vicepresident, Delphi Corp.
“The latest version of the Multec common rail system will provide higher pressures, more injection events and exceptional volume control. Looking ahead to Euro V, we are also introducing “Piezotec,” which we consider to be a unique piezo-based injector system, and expect to deliver a step change in fuel economy and exhaust emissions.”
The major benefit of APC, combined with the fast-acting solenoid injector, Delphi states, is exceptionally precise control of pilot injection. While existing technologies can provide a single pilot-injection event with a volume of around 1-2 mm3 at low injection pressures, they typically suffer from reduced metering accuracy during their life on the car, at idle or higher pressure.
The new Delphi system allows pilot volumes across the pressure range that remain stable between injectors throughout engine life. It enables engine designers to achieve mulitple injection low pressures for quiet idle and higher pressures for faster fuelling of cylinders and improved spray pattern, leading to improved torque and reduced smoke.
Dominique Chauvin, European managing director of Delphi Energy and Chassis Systems expects the Delphi injection system to maintain its outstanding refinement throughout its life. “APC allows engines fitted with Delphi injection systems to recalibrate as their characteristics change, eliminating this problem completely,” he says.
Another significant innovation in the Multec system is an inlet metering valve to more closely match the amount of fuel being pressurized in the common rail to demand at the injectors. Less energy is expended when lower pressures are required, leading to further fuel economy gains, Delphi states.
The technique also allows cost saving through the elimination of fuel cooling systems. Delphi also states that the fast actuation of the injector control valve eliminates the need for a rail pressure discharge valve. Ford is set to be one of the first vehicle manufacturers to use the high performance second generation common rail direct injection system, Alapont says. “With Ford, we have demonstrated the capabilities of these technologies and the tremendous potential that they offer.”
To manufacture the new common rail system, Delphi has installed a super-clean facility in La Rochelle, France, for the injector and final assembly in Barcelona, Spain, for the pump. “We have paid particular attention to quality, aiming for a long and reliable service life,” says Guy C. Hachey, president of Delphi Energy & Chassis Systems.
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