|2011 Ecotec 1.4L I-4 VVT Turbo (LUJ) for Chevrolet Cruze. Click to enlarge.|
Internationally, customers have purchased 140,000 Chevrolet Cruze in the first six months of 2010 and a total of 270,000 since Cruze launched in the spring of 2009 in Europe, followed by other major markets, such as China in summer of 2009. Cruze sales are rising an average of 18% per month.
Cruze will begin arriving at US dealerships in September. The 2011 Chevrolet Cruze is powered by a new generation of small-displacement four-cylinder engines, including the Ecotec 1.4L turbo and the Ecotec 1.8L. The Ecotec 1.4L turbo is standard on Eco (earlier post), LT and LTZ models and helps the Cruze Eco achieve up to an estimated 40 mpg on the highway (with a standard six-speed manual transmission), which is expected to be the best fuel economy in the compact car segment.
Standard on Cruze LS models is the Ecotec 1.8L four-cylinder, which features a variable intake manifold for optimal performance across the rpm range. It is rated at 136 hp (103 kW) and 123 lb-ft of torque (168 N·m) at 3,800 rpm.
Both of Cruze’s new engines are part of Chevrolet’s global range of small-displacement engines designed with fuel efficiency in mind, including technology such as full variable valve timing that optimizes performance and fuel economy. They are matched with fuel-saving six-speed manual and six-speed automatic transmissions.
Power-dense small-displacement engines with turbocharging and variable valve timing, such as the Ecotec 1.4L turbo, are integral in our advanced technology strategy.
—Mike Katerberg, assistant chief engineer, Powertrain
|Ecotec 1.4L Turbo Airflow. Outside air is drawn into the intake air box by the turbocharger compressor wheel. The compressor wheel is being driven by hot exhaust gases coming out of the exhaust manifold. The air is forced through an intercooler by the compressor wheel and then travels to the intake manifold. The intake manifold distributes the air to the cylinders where fuel is added and the combustion process takes place. A wastegate opens to regulate the compressor drive power by letting excess exhaust gases escape through the exhaust pipe. Click to enlarge.|
Ecotec 1.4L Turbo. The Ecotec 1.4L turbo delivers 138 horsepower (103 kW) and 148 lb-ft (201 N·m) of torque between 1,850 rpm and 4,900 rpm. The wide rpm range for the maximum torque—a specific trait of turbocharged engines—helps the engine deliver a better driving experience and performance.
Key Ecotec 1.4L Turbo design features include:
Cylinder block:. The cylinder block is made of strong gray cast iron, with five reinforced main bearings. The block offers excellent thermal properties that suit the cylinder pressure and loads generated by a turbocharger system. To minimize weight, it features hollow-frame construction, making it about 20% lighter than a conventional casting. The block also incorporates a gray cast iron bedplate that helps reduce engine vibration.
The cylinders within the block are triple-honed for a smoother finish that minimizes piston friction and overall wear, while also optimizing oil and fuel consumption.
Crankshaft. The Ecotec 1.4L turbo uses a reinforced, solid-cast crankshaft that offers greater strength and stiffness, particularly at higher rpm, to support the boosted cylinder pressure of the turbo system.
Connecting rods and pistons. Like the crankshaft, the connecting rods and pistons are designed to support the greater load of the turbo system. The connecting rods are forged steel and the lightweight hypereutectic pistons are designed with a thicker crown area and a unique ring pack to withstand the boost pressure and heat generated by the turbo system. The engine’s compression ratio is 9.5:1.
Variable-flow oil pump. The Ecotec 1.4L turbo uses a unique, variable-flow oiling system that helps maximize fuel efficiency. It is accomplished with a crankshaft-driven oil pump that matches the oil supply to the engine load, rather than the linear operation of a conventional, fixed-flow pump. The Ecotec 1.4L turbo’s variable-flow pump changes its capacity based on the engine’s demand for oil. This prevents using energy to pump oil that is not required for proper engine operation.
Piston-cooling oil jets. The Ecotec 1.4L turbo incorporates piston-cooling oil jets to minimize piston temperatures—helping to optimize performance, efficiency and emissions. The jets are part of the engine’s oiling circuit, mounted at the bottom of each cylinder, and spray engine oil at the bottom of the pistons.
Oil-water cooler. The Ecotec 1.4L turbo requires an engine oil cooler to maintain optimum oil temperatures. It has a heat exchanger incorporated into the oil filter housing. Coolant to the heat exchanger is provided by the engine’s coolant circuit. The design optimizes oil cooling with a minimal pressure loss. During the cold starting, the system also enables faster heating of the engine oil for an earlier reduction of internal engine friction.
Structural oil pan. An aluminum oil pan is designed as a key structural component of the engine, adding stiffness that helps improve vibration characteristics.
Cylinder head. The Ecotec 1.4L turbo uses an aluminum cylinder head with dual-overhead camshafts and four valves per cylinder. The head’s intake port design optimizes performance, efficiency and emissions by promoting greater charge motion of the intake air and a more complete burn of the air/fuel mixture. Sodium-filled exhaust valves are designed for the higher combustion temperatures of the turbo system.
Variable valve timing. The dual-overhead camshaft arrangement of the engine employs dual continuously variable cam phasing to adjust the engine valves’ opening and closing timing for optimal performance, fuel efficiency and emissions across the rpm band—including greater low-rpm torque. The intake and exhaust cams can be phased up to 60 crankshaft degrees. Cam phasing also eliminates the need for conventional exhaust gas recirculation, by optimizing the amount of exhaust gas in the combustion chamber. A vane-type camshaft phaser with an integrated oil-control valve is used for lower weight and greater packaging flexibility.
Hollow-cast, chain-driven camshafts. The pair of camshafts in the Ecotec 1.4L turbo is hollow and lighter than conventional solid shafts. Along with helping reduce the overall weight of the engine, they lower the inertia of the valvetrain, allowing the engine to rev higher and more quickly. The camshafts are driven by durable, maintenance-free chains.
Roller-finger camshaft followers. A low-mass DOHC roller-finger camshaft follower is used to minimize friction and maintenance. It operates with very low frictional losses, helping enhance efficiency and lower emissions. The hydraulic lash adjusters and the chain cam drive require no maintenance during the life of the engine.
Integrated turbocharger and exhaust manifold. For lower weight, quicker throttle response and easier packaging in the Cruze, the Ecotec 1.4L turbo uses a unique, integrated turbocharger and exhaust manifold. The turbocharger size was chosen with an emphasis on low-speed torque and throttle response. Typically, turbochargers are mounted at the outlet of the exhaust manifold or farther downstream in the exhaust system, but this design incorporates the turbocharger’s turbine housing into the exhaust manifold as a single component. It requires fewer parts, is lighter than a conventional system, helps lower engine compartment temperatures and helps the engine warm up faster. The faster warm-up benefits emissions performance, as it enables a close-coupled catalytic converter that promotes a quick “light off.”
The turbocharger is lubricated by engine oil and is liquid cooled for long-term reliability. The pressurized air charge is cooled via an air-to-air intercooling system prior to entering the engine. This lowers the temperature of the inlet air for more a more effective boost charge.
Electronically controlled thermostat. The coolant thermostat’s operating point is electronically controlled to optimize engine temperatures during different phases of operation to enhance fuel efficiency. The engine control module monitors sensors and controls the thermostat based on mapping that takes into account the wide range of engine operating conditions, including temperature and load.
In addition to fuel efficiency, turbocharged engines also deliver favorable performance density; the Cruze’s new 1.4L engine delivers approximately 100 horsepower per liter. Turbocharging of small-displacement engines is most effective on small-to-midsize vehicles that enable a more favorable torque-to-curb weight ratio, GM says.
Our research shows that turbocharging can deliver comparable torque to a non-charged engine that is 60-percent larger in displacement
Ecotec 1.8L. The Chevrolet Cruze’s naturally aspirated Ecotec 1.8L engine (standard on Cruze LS) has many of the same features of the Ecotec 1.4L turbo. It is a compact and durable four-cylinder engine that combines competitive performance with sophisticated technologies, such as a variable-geometry intake manifold, low maintenance, low emissions and excellent fuel efficiency. Highlights include:
- Structural, lightweight (hollow-frame) cast gray iron cylinder block
- Dual-overhead camshaft configuration with four valves per cylinder
- Dual continuously variable camshaft phasing
- Variable intake manifold
- Lightweight direct-acting hydraulic tappets with reduced friction
- Hollow-cast camshafts
- Oil-water heat exchanger
- Piston-cooling oil jets
- Electronically controlled cooling system
- Extended-life coolant
- Long life (100,000-mile) spark plugs
The Ecotec 1.8L’s two-stage variable intake manifold optimizes fuel economy and performance. At engine speeds below 4,000 rpm, inlet air passes through 35.8-inch-long (910 mm) intake tracts that help increase torque. At speeds greater than 4,000 rpm, a rotary sleeve within the lightweight composite intake manifold closes off the full length of the intake tracts, forcing air through a shorter, 10.2-inch (260 mm) path that helps build horsepower.
The rotary sleeve helps minimize airflow resistance at higher speeds, ensuring the maximum cross section area in the open position. The cross section of the intake runners is constant, with the length of the runners reduced by 60 percent in the closed position (greater than 4,000 rpm). This two-stage manifold helps the Ecotec 1.8L produce approximately 90 percent of peak torque from 2,400 rpm to 6,500 rpm, giving it a strong, responsive feel in all driving conditions.
Six-speed transmissions. A pair of six-speed transmissions—a six-speed manual and a six-speed automatic—match the Ecotec 1.4L turbo for optimal performance and fuel efficiency. The six-speed manual transmission delivers a wide spread of ratios with a “tall” top gear that optimizes fuel economy. The gearing in the Cruze Eco’s six-speed is specific, and helps the model achieve its estimated highway rating of up to 40 mpg. All of the Cruze’s six-speed manual transmissions include triple-cone synchronization in first and second gears for easier engagement, as well as a synchronized reverse gear.
The six-speed automatic’s torque converter design and transmission gearing bolster engine power and contribute to a stronger feeling of performance. It features an on-axis design that allows more compact packaging that enhances crash crumple zone performance, interior space and a lower, sleeker hood line. Rather than the transmission being “folded” around the end of the engine, the on-axis design puts the gear sets on the same axis as the engine crankshaft centerline.
Shifts within the automatic transmission are accomplished by applying and disengaging clutches simultaneously, which provides a more direct feel to the driver, compared to “freewheeling” gear change mechanisms. On the road, a wide selection of shift patterns is adapted to the styles and habits of the driver, anticipating when maximum acceleration or maximum efficiency is required. The electronic control also adapts to the prevailing road conditions, reducing gear shifting when climbing or descending and using engine braking assistance during down changes.
The six-speed automatic also features ActiveSelect manual control, which allows sequential driver gear selection via the shift lever. The transmission also has neutral gear disengagement at idle, which reduces vibration and improves fuel economy.
Production and pricing. The US Cruze models will be produced in Lordstown, Ohio—one of the few compact car built in the US for 2011 model year. Production at the Lordstown complex will begin with three shifts, assembling Cruze models around the clock to meet expected customer demand.
In the US, Cruze models will start at $16,995 for the LS model, equipped with the most standard safety features in its segment, including 10 air bags, StabiliTrak electronic stability control with rollover sensing, traction control and anti-lock brakes.
The Cruze Eco model starts at $18,895, featuring a standard 1.4L Ecotec turbo and six-speed manual transmission. With ultra low-rolling resistance tires, and an enhanced aerodynamic-performance package, Cruze Eco is expected to deliver 40 miles per gallon on the highway.
The top of the line Cruze LTZ model starts at $22,695 and features a standard six-way power driver seat, leather seating surfaces, cruise control, Bluetooth phone connectivity, USB port with audio interface, ultrasonic rear-parking assist, and 18-inch alloy wheels.
Cruze is currently available in more than 60 countries, with China, Russia, Mexico, India and Spain as the top five sales markets. Including Holden and Daewoo versions sold in Australia and South Korea, total sales exceed 340,000 vehicles across five continents.