General Motors South Africa has announced the introduction of a 2.2 litre turbo diesel engine option for the popular Chevrolet Captiva SUV. This latest generation common rail diesel engine with variable geometry turbocharger produces 135kW @ 3800 r/min and 400Nm of torque at 2000 r/min. Drive is through a 6-speed automatic transmission to all four wheels. This top of the range diesel Captiva features Chevrolet’s comprehensive LTZ specification level.
Chevrolet’s 2.2 litre DOHC turbo and intercooled diesel engine is one of the most powerful and fuel efficient engines in its class. At the core of this is its advanced design and the incorporation of a high-pressure common rail fuel injection system – the system pressure is 1800 bar – together with variable geometry turbocharger (VGT).
Highlights of this latest generation turbo diesel engine include a double overhead camshaft configuration with four valves per cylinder and variable swirl combustion chamber design for optimised combustion, enhanced performance, and minimised emissions with reduced diesel particulates. Engine vibration and knock have also been minimised for improved durability.
Camshaft timing is by way of a chain drive for improved timing accuracy and lower maintenance costs. A hydraulic tensioner in the chain drive ensures that the system always operates within its tight timing specification. The chain drive system also contributes to a reduction in engine noise and vibration.
The diesel injection system is a high-pressure common-rail design operating at a pressure of 1800 bar. Precise timing and measurement of the fuel charge is accomplished by the use of solenoid type injectors. This system ensures an optimised fuel/air mixture and injector spray pattern into the combustion chamber.
The geometry of the vanes in the turbocharger is continuously variable to ensure the best possible flow of air to the engine. Electronic control is by means of pneumatic and position feedback sensors. A linear actuator in the system ensures fast response and a precise throttle movement for a smooth driving experience.
This all-new engine has a very rigid engine block, an aid to reduced NVH (noise, vibration and harshness). The advanced combustion chamber design has enabled the compression ratio to be reduced from in excess of 17:1 on previous engines, to 16,3:1. The result is an engine that boasts higher specific power with lower emissions than on the previous design.
Already a clean burning engine by design, the Chevrolet 2.2L engine has a high efficiency exhaust gas re-circulation cooler that channels unburnt exhaust gas back into the induction system for lower emissions. This system not only assists in lowering emissions but also improves engine life by improving combustion and reducing engine knock and vibration.
A close-coupled diesel particulate filter is included in the exhaust system to filter out post combustion particulates that are commonly seen as soot emissions from engines without this type of filter. The particulate filter system is maintenance free for the life of the vehicle and complies with Euro-5 emissions standards.
Other features of this engine include oil-jet cooled pistons, a balance shaft module integrated into the oil cooler for significantly reduced noise and vibration, and a dual-mass flywheel that eliminates low frequency resonance and transmission noise at low engine speeds.
The aluminium cylinder head is produced using a rotocast process for reduced weight. The spiral surface design of the intake ports assists in creating swirl in the intake charge for an improved fuel burn characteristic.
Chevrolet Hydra-Matic 6- speed automatic transmission
Drive is to all four wheels via a 6-speed Chevrolet Hydra-Matic 6T50 transmission. This is an advanced electronically controlled automatic transmission with a compact design.
The key concept behind this all-new 6-speed auto transmission is the small size and packaging of the unit. By placing the gearsets on the same axis as the engine crankshaft centreline Chevrolet transmission engineers have been able to realise a far more compact form for the transmission, particularly in the fore-to-aft dimension.
Rather than “fold” the transmission around the end of a transversely mounted engine, a normally bulky installation, the 6T50 transmission has its gear train arranged in line with the crankshaft centreline.
To save even more space the traditional “freewheel” gear change mechanism is replaced by a multiple clutch system with gearshifts accomplished by engaging and disengaging clutches simultaneously during gear shifts. Sophisticated electronics enable the precision timing required to synchronise the clutches.
An exception is the shift between first and second gears where there is a large difference between the ratios. In this instance a regular “freewheel” mechanism is used to provide a smooth transition.
Quick acceleration combined with efficient cruising
The selection of a 6-speed transmission has allowed a wide range of ratios to be used to optimise performance and economy. The first gear has a high ratio to facilitate good acceleration from rest. Conversely sixth gear is an overdrive ratio that allows for low engine revs at highway cruising speeds.
The electronic control of the transmission provides for adaptive shift control including automatic gradient braking. This instructs the transmission to remain in a lower gear rather than shift up if it senses that the vehicle is decelerating or coasting on a downgrade. This reduces the need for the driver to apply the brakes during a hill descent. The transmission control module receives inputs from sensors that monitor brake usage, vehicle acceleration rate, and throttle position. It can even monitor whether or not a trailer is hitched to the vehicle.
The torque converter used in the Chevrolet 6T50 transmission uses a single plate lock-up clutch which provides a mechanical coupling to the drive with no slippage and minimal power loss. The oval, or hyper-elliptical, form of the torque converter reduces the overall thickness of the component for an additional space and packaging advantage. GM’s electronic controlled capacity clutch (ECCC) technology assists in dampening vibrations.
The helical gears used in the transmission are precision ground and honed for the finest of tolerances. With closer tolerances the gears are less prone to producing transmission noise in the form of a whine or humming sound often associated with gear trains.
Proprietary transmission fluid lasts lifetime of transmission
The Chevrolet 6T50 automatic transmission fitted to the Captiva Diesel is filled with GM specification DEXRON-VI fluid that in normal usage will not need to be changed over the life of the transmission. This fluid was developed to have a very consistent viscosity profile for more consistent shift performance in extreme conditions. It also is highly resistant to degradation over time.
Feature packed Chevrolet LTZ specification level
The Chevrolet Captiva 2.2D LTZ boasts a host of high-level interior features including:
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Leather gear lever cover
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Leather steering wheel cover
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Leather trim
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Power steering
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Steering column adjustment for both height and reach
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Height adjustable driver’s seat
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Power adjustment for driver’s seat
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Lumbar adjustment
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Climate control air conditioner
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Electric windows front and rear
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Electric remote side mirrors with foldaway function and heating
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Heated rear window
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Moisture sensitive windscreen wipers
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Cruise control
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Automatic anti-dazzle rear view mirror
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Map lights
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Courtesy lights for boot, door, and glove box
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Automatic headlight activation
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Opening glass panel on tailgate
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Rear park assist
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Sunglass holder
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Sunroof
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Roof rails
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Front loading radio/CD combination with RDS/MP3/AUX/Bluetooth
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8 speakers
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Satellite controls for audio system on steering wheel
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On-board computer
The Captiva 2.2D LTZ, like all models in the Chevrolet Captiva range, is covered by a 5 year/120 000 km warranty with anti-corrosion cover for 5 years and unlimited kilometres. Roadside assistance is available for the full term of the warranty.
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Service intervals are 12 months or 15 000 kilometres.
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A 3 year/60 000 kilometre service plan is included in the price.
