GM 2.4 Liter I4 Ecotec Hybrid LUK Engine
The LUK is a hybrid engine system produced by General Motors for compact, midsize, and full-size vehicles. Displacing 2.4 liters in an I4 configuration, the LUK is part of the Ecotec engine family. It is essentially the LEA Ecotec but modified for GM’s Belt-Alternator Starter (BAS) mild-hybrid drivetrain. It is available on the Buick Regal eAssist and LaCrosse eAssist as well as on the Chevrolet Malibu and Impala.
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.
- 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.
|Type:||Ecotec 2.4L I4 VVT DI|
|Displacement:||2384 cc (145 ci)|
|Valve configuration:||Dual overhead camshafts|
|Valves per cylinder:||4|
|Assembly site:||Spring Hill, Tennessee|
|Valve lifters:||Hydraulic roller finger follower|
|Firing order:||1 – 3 – 4 – 2|
|Bore x Stroke:||88.00 x 98.00 mm|
|Bore Center (mm):||96.00 mm|
|Fuel system:||Direct injection|
|Fuel type:||Regular unleaded|
|Horsepower hp (kw)|
|Buick Regal||182 hp (136 kW) @ 6700 rpm SAE Certified|
|Buick Lacrosse||182 hp (136 kW) @ 6700 rpm SAE Certified|
|Chevrolet Malibu||182 hp (136 kW) @ 6700 rpm SAE Certified|
|Chevrolet Impala||182 hp (136 kW) @ 6700 rpm SAE Certified|
|Torque lb.-ft. (Nm)|
|Buick Regal||172 lb-ft. (233 Nm) @ 4900 rpm SAE Certified|
|Buick Lacrosse||172 lb-ft. (233 Nm) @ 4900 rpm SAE Certified|
|Chevrolet Malibu||172 lb-ft. (233 Nm) @ 4900 rpm SAE Certified|
|Chevrolet Impala||172 lb-ft. (233 Nm) @ 4900 rpm SAE Certified|
|Maximum Engine Speed:||7000 rpm (forward gears)|
|SAI system, PZEV capable|
|Positive crankcase ventilation|
|Cylinder head:||Cast aluminum|
|Exhaust manifold:||High silicon molybdenum, cast nodular iron|
|Main bearing caps:||Aluminum bedplate|
|Crankshaft:||Cast nodular iron|
|Camshaft:||Cast nodular iron|
|Connecting rods:||Forged steel|
|Extended life spark plugs|
|Extended life coolant|
|Electronic throttle control|
|Variable valve timing|
|Belt driven Motor/Generator and Lithium Ion Battery System:||Liquid cooled Motor Generator (MGU) with air cooled power electronics and battery pack|
|Maximum Electric Generating Power:||15 kW @ 1570 – 3180 RPM*|
|Maximum Electric Motor Torque (Cranking):||150 Nm*|
|Maximum Electric Motor Torque (Electric Assist):||107 Nm @ 1000 RPM*|
|Maximum Electric Motor Power (Electric Assist):||11.2kW (15 hp) mechanical @ 1000 – 2200 RPM*|
|Lithium Ion Battery:||115 V, 0.5 kW-hr, 15 kW peak power|
|*All torque and speed values are @ engine crankshaft|
|Buick LaCrosse||MHH-6T40-Aux Pump|
|Buick Regal||MHH-6T40-Aux Pump|
|Chevrolet Malibu||MHH-6T40-Aux Pump|
|Chevrolet Impala||MHH-6T40-Aux Pump|