GM 2.4 Liter I4 Ecotec Hybrid LUK Engine

The Ecotec 2.4L LUK uses a state-of-the-art lithium-ion battery system and electric motor-generator to enable regenerative braking capability to improve fuel economy by an estimated 25 percent. The engine is based on the proven Ecotec 2.4L engine, but with features to support the eAssist system.

Engine highlights:

• eAssist System: the eAssist system uses power stored in an advanced, 115V lithium-ion battery and channels it to a 15-kW motor generator to provide an electrical boost in various driving scenarios, optimizing engine and transmission operation and increasing fuel economy through:
  • Regenerative braking, which provides up to 15 kW of electricity to charge the battery
  • Providing up to 11 kW (15 hp) of electric power assistance during acceleration
  • Automatic engine shut-off when the vehicle is stopped
  • Aggressive fuel cut-off during deceleration down to zero vehicle speed, enabled by the torque smoothing provided by the motor-generator unit
  • Intelligent charge/discharge of the high-voltage battery.
• Engine Block: the Ecotec 2.4L’s sand-cast cylinder provides excellent structural support, as well as enabling greater control of noise, vibration and harshness. The main bearing bulkheads, which support the crank bearing, as well as the cylinder bore walls, have been significantly strengthened to support increased engine loads.
• Aluminum Pistons with Jet-Spray Cooling: the Ecotec 2.4L’s pistons use lightweight aluminum pistons, for less reciprocating mass inside the engine that enhances efficiency, decreases vibration and bolsters the feeling of performance as rpm increases. Each piston has its own directed jet that sprays oil toward its skirt, coating its underside and the cylinder wall with an additional layer of lubricant. The extra lubrication cools the pistons, reducing friction and operational noise, while also bolstering the engine’s durability.
• Cylinder Head: the Ecotec 2.4L has a SPM 319 aluminum cylinder head that is cast with advanced semi-permanent mold technology. This provides excellent strength, reduced machining and optimal port flow. The cylinder head is designed specifically for direct injection into each combustion chamber and includes premium valve seat, valve guide and valve materials. The cylinder head also has integral cast oil passages that feed a set of internal oil control valves that activate cam phasers, enabling variable valve timing.
• DOHC with Continuously Variable Valve Timing: overhead cams are the most direct, efficient means of operating the valves, while four valves per cylinder increase airflow in and out of the engine. This arrangement is integrated on the Ecotec 2.4L’s lightweight aluminum cylinder head. Both the intake and exhaust cams have hydraulically operated vane-type phasers that are managed by a solenoid and directed by the engine control module (ECM).
• Direct Injection: direct injection moves the point where fuel feeds into an engine closer to the point where it ignites, enabling greater combustion efficiency. Direct injection also reduces emissions, particularly cold-start emissions, by about 25 percent. With direct injection, the higher compression ratio is possible because of a cooling effect as the injected fuel vaporizes in the combustion chamber. This reduces the charge temperature and lessens the likelihood of spark knock. The direct injection fuel injectors have been developed to withstand the greater heat and pressure inside the combustion chamber and also feature multiple outlets for best injection control.
• Cam-Driven High-Pressure Fuel Pump: a high-pressure, cam-driven pump provides the fuel pressure required of the direct injection system in the Ecotec 2.4L. The engine-mounted fuel pump is augmented by a conventional electrically operated supply pump in the fuel tank.