18/2/12

Overview: Chevrolet Aveo

It would be wishful thinking to say that the previous Chevrolet Aveo was an unqualified sales success. But with the brand associated for some time with frightful Pacific-rim cars like the Daewoo Matiz, perhaps a shaky start on the British market was to be expected. Things are changing now, though, with Chevrolet settling down to sell its own interesting mixture of Euro-American products, from the Aveo to the Corvette by way of a couple of crossovers — and, of course, the forthcoming Volt serial hybrid.

The new Aveo (known elsewhere as the Sonic) is, as much as anything is, a completely new car. The structure and running-gear, clothing panels and interior have been completely redesigned. As we have come to expect of every new model, much is made of the widespread use of high-strength steel in the monocoque and the resulting improvements to torsional stiffness that this provides. As usual, no actual figure is provided, but apparently the roof can support up to 4.2 times the car’s weight. This is not a statistic that we have seen quoted elsewhere, so we cannot make a meaningful comparison, though we are reminded of Peugeot’s entertaining if dubious advertisement for the 504 which depicted a car with an elephant standing on the top.

Chevrolet Aveo: New model (top) and old model (above).

Selling price is important with small cars, so it would be unreasonable to expect genuine technical novelty, and indeed there isn’t any. Wheel location at the front is by means of McPherson struts with coil springs and an anti-roll bar; behind you will find a torsion-beam arrangement. The usual off-the-shelf electronic driver-assistance and safety systems are fitted: stability control, anti-lock and brake-assist. Electric power-steering is fitted to diesel and 1.2-litre petrol variants; the system includes a wear compensator. We are rather surprised that EPS isn’t fitted to all models. The design of the front strut modules incorporates a measure of compensation for side loads, which reduces friction in the load-unload plane. The torsion beam is of a tubular V-shape design, and double-walled. Gas-charged dampers are used at the rear.

With passenger-side airbags universal now, it’s very unusual to find a car with much stowage in the dash. The Aveo bucks this trend by coming with two gloveboxes. Neither is enormous, but the thought is appreciated. The upper compartment is equipped with a USB socket: any electronic device plugged in here can be operated through the steering-wheel controls.

Engines

Five power-units are available. Two are G.M. Europe petrol engines, of 1.2- and 1.4-litres; the others are variants of the 1248cc four-valve Fiat diesel in 75PS, 95PS and 95PS ‘Eco’ trim. All are familiar from the Vauxhall Corsa, and there are even more versions of the diesel unit, with different outputs, in assorted Fiat Group products.

The petrol engines feature a cylinder block based on a hollow-frame structure, with a cast-iron bedplate. The compression ratio, at 10.5:1, is high for an indirectly fuelled petrol engine.

Both sizes of petrol engine use two camshafts, four valves per cylinder and variable valve timing. An oil/water heat exchanger is used. The block and aluminium head have dedicated bores for lubrication of the timing gears. Unusually for an atmospheric engine, the pistons are cooled by oil jets directed at their undersides.

Other highlights of the petrol engines include a 6.3mm ‘silent’ chain drive for the camshafts and an exhaust manifold manufactured from stainless steel, with an integrated catalytic converter.

Instrumentation is a matter of taste.

The 1229cc petrol engine is expected to be the most popular power-unit; headline outputs are 86PS and 115Nm — the latter at a very busy 4000rpm. Claimed performance figures for the manual transmission 1.2 Aveo include a maximum speed of 107mph and a 0-100km/h time of 13.6s. Fuel economy over the NEDC rolling-road test régime is 60.1mpg, equivalent to CO2 emissions of 111g/km. The 1.4 petrol engine offers 100PS and 130Nm — the torque curve again peaking at 4000rpm. All petrol engines are fitted with stop/start as standard.

The 1248cc Fiat diesel engine is built in many forms with different power and torque outputs. Depending on the version, it comes with a turbocharger of either fixed or variable geometry, and (rather oddly) it is built variously with hydraulic or solid tappets. Here, the 95PS versions — of which there are two — are fitted with variable exhaust gas nozzles, while the 75PS variant has a fixed nozzle.

Transmissions

A five-speed manual transmission is standard with all engines bar the 95PS diesels, which have a six-gang. A new G.M. ‘Hydra-Matic’ six-speed epicyclic automatic is optional with the 1398cc petrol engine.

Both five-speed manual transmissions deployed in the Aveo use a single-piece, lightweight aluminium housing and feature triple-cone synchronisers for first and second gears. In the Hydra-Matic six-speed automatic, all of the gear-sets are positioned on the same axis as the engine crankshaft centre-line, making the powertrain shorter.

The business of making the new car’s shell stiffer than the old one’s has seen an increase in the number of spot-welds by 10 per cent. Some of the steel exhibits tensile strengths of 1000MPa or higher — considerably stronger than the 340-550MPa seen in the previous generation Aveo. The chassis’ main underbody rails run continuously from front to rear. The new Aveo has been awarded five stars in NCAP safety testing.

The power-train is mounted on a six-mount cradle, which is constructed from hydro-formed steel. The engine mounts, which include a hydraulic mount, use the engine’s torque axis to absorb vibration.

The new car’s stiffer structure allows — in principle at least — for better control of NVH. Thanks to an excellent drag co-efficient of 0.30 Cd, the Aveo records wind noise of 40.5dB at motorway speed.

The noise damping mats, used for absorbing high-frequencies, are tailored to each powertrain package. The use of thicker glass is also aimed at reducing noise, as are the fitting of composite nylon baffles in various structural intrusions and formed resin or felt blanket under the bonnet panel. Liquid-applied sound deadening (LASD), in the form of melt-on patches, is applied to parts of the interior body structure; smaller section joints that might resonate are damped. Compared with more conventional damping material, applied by adhesive, these patches fit almost perfectly in the areas to which they are applied. As a result — Chevrolet claims — LASD achieves up to 40 per cent. greater sound damping performance over the conventional materials.

Typically, LASD materials are water-based, and applied at a little over 3MPa with a coating thickness of between 1.5mm and 4mm.

The standard electronic stability control (ESC) system can apply individual brakes selectively to counterbalance oversteer or understeer. The standard anti-lock braking system has a brake assist system (BAS) and electronic brake-force distribution (EBD). Front disc and rear drum brakes are standard. The front brakes feature ventilated single 54mm or 60mm steel calipers, depending on the engine; at the rear, 19mm or 20.6mm steel cylinders are used.

Equipment plugged into the USB port in the upper glovebox can be controlled by way of the steering-wheel switchgear.

More than 60 per cent. of the body, plus the engine cradle, is made from high-strength steel. Ultra-high-strength steel is integrated in the forward portion of the rockers and the centre cross-bar.

The Aveo’s engine cradle distributes energy in frontal and side impacts. Together with the front bumper system and the engine compartment rails, the engine cradle bars absorb the brunt of a frontal crash.

The front hinge and A- and B-pillar zones are reinforced. A collapsible pedal assembly is fitted.

Parcel shelf stows neatly.

According with industry practice, the sensors that control the deployment of the airbags — six are fitted — are mounted into the Aveo’s structure. The centre-line of the vehicle incorporates the sensing and diagnostic module, which receives data from the sensors, determining the severity of an impact and deciding whether to deploy the airbags. The Aveo uses single-stage airbags for the driver and front passenger, plus roof-rail airbags and side-impact airbags.

The B-pillars contain side-impact sensors that trigger the roof-rail airbags, as well as seat-mounted thorax airbags and seatbelt pre-tensioners. If the Aveo’s onboard sensors register excessive roll on a flat road surface, the brakes are activated to reduce lateral force.

When activated, the Aveo’s cruise control allows the driver to set a maximum speed: the system triggers an audible alarm once this speed is reached. Ultrasonic parking sensors are optional.

All five seating positions have three-point seatbelts; the front seats have pre-tensioners.

To reduce injury to pedestrians, the Aveo’s bumper system includes an energy absorber that surrounds the bumper beam to reduce the force of a potential impact.

Chevrolet Aveo 1.2 1.4 1.3D
75PS
1.3D
95PS
1.3D
95PS Eco
Cylinders 4I 4I 4I 4I 4I
Valves 4 4 4 4 4
VVT I I
Aspiration/
geometry
A A T/f T/v T/v
Bore/stroke 73.4/72.6 73.4/82.6 69.6/82.0 69.6/82.0 69.6/82.0
Swept volume 1229cc 1398cc 1248cc 1248cc 1248cc
Compression
ratio
10.5:1 10.5:1 16.8:1 16.8:1 16.8:1
PS/rpm 86/5600 101/6000 75/4000 95/4000 95/4000
Nm/rpm 115/4000 130/4000 190/1750 210/1750 190/1750
Maximum speed 107 108 101 108 108
0-100km/h 13.6 12.2 14.2 12.6 11.7
Urban MPG
(l/100km)
48.7
(5.8)
41.5
(6.8)
65.6
(4.3)
58.8
(4.8)
67.2
(4.2)
CO2 g/km 111 125 99 108 95
Emissions EU5 EU5 EU5 EU5 EU5
Transmission M5 M5 M5 M6 M6
Final drive ratio 4.188 4.625 3.737 3.722 3.550
Driven wheels Front Front Front Front Front
Fuel tank 46l 46l 46l 46l 40l
Kerb mass † 1064 1089 1172 1185 1165
PS/t 80 92 64 80 81
Nm/t 108 119 162 177 163
Length 4039 4039 4039 4039 4039
Width 1735 1735 1735 1735 1735
Height 1517 1517 1517 1517 1517
Wheelbase 2525 2525 2525 2525 2525
Track
— front
— rear

1509
1509

1509
1509

1509
1509

1509
1509

1509
1509
† DIN or EU not stated.
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