Biodiesel Resource

July 8, 2005 -- The Renault-Nissan alliance is introducing a new 2.0-liter dCi diesel engine, to be first applied in a 150-hp version in the Laguna this summer. All versions of the 2.0 dCi engine meet Euro 4 emission standards. NOx and particulate emissions are minimized by precise control over fuel injection, and various pre-exhaust pollution control systems. Low fuel consumption ensures the lowest possible CO₂ emission.

The new powerplant will be released in several variants with different power and torque capabilities, for gradual rollout on other vehicles.

The 2.0 dCi introduces a number of engineering upgrades, including improved internal cylinder aerodynamics to make the most of the piezoelectric injector capabilities.

The 2.0 dCi features four valves per cylinder. Intake and exhaust ducts are face-to-face across the cylinder head, with each camshaft operating intake and exhaust valves. This configuration improves cylinder filling and exhaust gas evacuation. The difference in angle between intake and exhaust ducts produces a dual swirl effect, for improved air-fuel mixing.

A Bosch piezoelectric-controlled injection system provides fast, precise control over fuel injection. Response is up to four times faster than with a classic solenoid system, enabling engineers to opt for an injection cycle with five squirts: two pre-squirts, one main squirt and two post-squirts.

The pre-squirts, which pre-heat the combustion chamber in preparation for the main squirt, improve engine acoustics by minimizing the characteristic diesel clatter. The post-squirts sustain the main injection combustion, to burn off soot and thus bring down pollutant emissions before the exhaust gases have even left the combustion chamber.

An exhaust gas recirculation system taps off some of the exhaust gas leaving the combustion chamber and feeds it back directly into the intake. The amount of recirculated exhaust gas is controlled by a valve that regulates the inflow on the basis of various engine parameters.

This method produces a controlled temperature rise in the combustion chamber to reduce pollutant emission levels and enhance the engine’s overall environment performance.

Renault Laguna 150-hp 2.0 dCi

• Displacement: 1,995 cc
• Valves: 16
• Compression ratio: 16.0:1
• Power: 150 hp (110 kW)
• Torque: 340 Nm (251 lb-ft)
• Cd: 0.62
• Fuel Consumption (combined): 5.8 liters/100km
• Fuel Economy: 40.6 mpg US
• Emissions: Euro 4
• CO₂: 154 g/km

A higher-powered 175-hp version of the 2.0 dCi will come standard with a self-regenerating particulate filter. When the filter fills up, the engine runs a regeneration cycle, performing a second post-injection to deliberately overheat the exhaust gas, oxidizing the soot in the filter filter, freeing up the device’s capacity.