The powertrain options for the Sonic drawn from a range of latest technology small capacity four-cylinder petrol engines that offer a superb balance between performance and efficiency. Outstanding refinement and fuel efficiency, together with power and torque across a wide engine operating range ensure an enduring fun-to-drive experience.
At launch the engines offered in the Sonic Hatch in South Africa will be 1,4 and 1,6 litre four cylinder petrol engines. A 1,3 litre turbocharged, common rail, direct injection diesel engine is an option for release at a later date. Drive is via a 5-speed manual transmission for both the 1,4 and 1,6 derivatives while the 1.3 diesel will be paired with a 6-speed manual transmission.
These latest generation engines from Chevrolet offer a host of advanced technologies including double continuous variable cam phasing (DCVCP).
Latest generation 1,4 litre petrol engine
The 1,4 litre petrol engine option for the Chevrolet Sonic produces maximum power of 74kW @ 6000 r/min and peak torque of 130Nm @ 4000 r/min. Combined cycle fuel economy is estimated at 5,8 l/100km.
This engine is a member of the newest family of small displacement engines from Chevrolet. Packed with latest technology features, this family of engines is ranked amongst the most advanced and refined in the global small car segment.
Double Continuously Variable Cam Phasing (DCVCP)
DCVCP, an enhanced form of variable valve timing, allows the intake and exhaust valve timing to be continuously varied according to driving conditions at any given moment with the accent on performance or economy depending on operating conditions and engine speed. An extremely compact and lightweight hydraulic vane type phaser is used to achieve the required camshaft timing adjustments.
Advantages offered by this system include:
The advantage of being able to produce higher power and torque figures over a wider engine operating range due to optimised charging of the cylinders with the fuel/air mixture
Reduced emissions as a result of high gas recirculation rates
Reduced fuel consumption as a result of a de-throttled intake charge cycle.
The four-valve per cylinder configuration with twin overhead camshafts offers a high level of performance and economy due to the inherent excellent gas flow characteristics of this type of engine. The layout of the cylinder head offers an optimised design for both the inlet and exhaust ports with efficient cooling of the cylinder head aided by the thermal properties of the aluminium cylinder head casting.
Roller type finger cam followers with a hydraulic lash adjuster are employed for a maintenance-free valve train.
A host of high-tech features
The cylinder block is made from cast iron and has a hollow frame structure with cast iron bedplate for added rigidity. This results in a smooth running engine with excellent noise, vibration and harshness (NVH) characteristics.
The crankshaft and connecting rods have a high strength design that offers a low NVH characteristic.
A flow controlled variable displacement oil pump is utilised for improved lubrication. The low power draw-off of this latest generation type oil pump contributes to improved fuel efficiency.
A compression ratio of 10,5:1 ensures a high level of thermal efficiency that translates into more efficient power extraction from the measured intake charge.
A stainless steel fabricated exhaust manifold with an integrated catalytic converter is employed for enhanced emissions performance.
An electronically controlled thermostat effectively monitors and controls engine warm-up at start-up and cooling during operation. This ensures optimal engine operating temperature which contributes to improved fuel efficiency and lower emissions.
The pistons incorporate cooling oil-jets for enhanced lubrication and increased durability.
The toothed timing belt has a change interval of 160 000 kilometres or 10 years.
Platinum-tipped spark plugs need only be changed every 160 000 kilometres. The spark plugs are activated by a coil-on-plug system that eliminates plug wires for improved operating reliability and reduced maintenance.
1,6 litre petrol engine
Like the 1,4 litre petrol engine available in the Sonic, the 1,6 litre petrol engine is also a new generation 16-valve four cylinder unit with twin overhead camshafts. This engine produces maximum power of 85kW @ 6000 r/min with peak torque of 155Nm @ 4000 r/min. Combined cycle fuel economy for this engine in the Sonic is estimated at 6,5 l/100km.
The DCVCP (Double Continuous Variable Cam Phasing) featured on the smaller engine is also included in this engine specification. On the 1,6 litre power plant management of the intake charge is taken a step further with constant length intake runners for optimised efficiency and a quieter and more refined intake noise. A laterally positioned throttle valve ensures maximised efficiency in the transfer of air from the air filter through to the cylinders.
Temperature management on this engine is assisted by a highly efficient oil-water heat exchanger with a MAP (Manifold Absolute Pressure) sensor controlled thermostat ensuring that the engine always operates within its optimum temperature range.
Once again a deep drawn fabricated stainless steel exhaust manifold with integrated catalytic converter is fitted.
Throughout the design process for these latest generation engines from Chevrolet weight reduction and overall efficiencies were a key consideration. Despite a number of new features included in the specification Chevrolet powertrain engineers tasked with the development of this latest family of small capacity engines have succeeded in reducing engine mass by as much as 3% compared to equivalent previous generation engines. At the same time the overall stiffness and structural strength of the engines has been increased for improved durability and lower NVH.
Modern casting techniques have allowed the hollow frame concept for the block to be refined to a point that a weight saving of 20% has been achieved on the engine block despite increased strength. The grey cast iron block on this engine weighs in at just 27 kg including the bearing caps.
Carrying the increased strength/reduced weight concept through to other major engine components, the engineering team arrived at a new design for the crankshaft, connecting rods, and pistons that offered an advantage over previous components.
The new crankshaft design achieved a weight saving of 6% without any sacrifice in strength or torsional stiffness. At the same time the degree of balancing of the rotating mass was improved by 60%. A new technology anisotropic magnetoresistive (AMR) crankshaft sensor system is incorporated in a plastic module together with the crankshaft seal that is pressed into the cylinder block. The ensures more accurate and reliable measuring of the crankshaft position at all times for smoother and more efficient operation.
The connecting rods have a floating piston pin bearing. The pistons themselves are of a new lightweight design that incorporates oil cooling jets to compensate for the increased piston temperatures generated by the improvement in engine performance.
Oil circulation has been increased for added durability and performance. The oil system on the Sonic 1,6 litre engine has an integrated oil/water heat exchanger that ensures maximum cooling of the oil with a minimum reduction in oil pressure. During cold starts this system enables the faster raising of the oil temperature to its normal operating level and a consequent reduction in internal friction in the engine. To accommodate the increased oil flow requirements of the piston cooling and cam phaser technologies the oil pump has a high rate of flow.
Thermal management of the engine through efficient water flow ensures optimised efficiency and lower emissions. The Chevrolet engineering team responsible for this engine made extensive use of computational fluid dynamics (CFD) computer software to simulate the flow, speed, and distribution of the coolant through the cooling system to significantly improve the heat transfer characteristics.
The latest technology MAP (Manifold Absolute Pressure) thermostat allows the ignition timing to be advanced, retarded, or maintained as required based on manifold pressure at any given time to control engine cooling. The operating temperature of the engine has been reduced which contributes to improved fuel efficiency by reducing engine friction.
Reduced maintenance items include the toothed timing belt that has a life of 160 000 kilometres of 10 years, and nickel tipped spark plugs with a life of 60 000 kilometres. A coil on plug system is utilised on this engine.
Together the new generation 1,4 litre and 1,6 litre petrol engines fitted to the new Sonic Hatch offer a superb balance of power and economy for an altogether fun driving experience.