6/8/11

Overview: BMW 1-series

BMW’s 1-series has been a more than tolerable success for the Company, and its new incarnation sets out to improve rather than completely reinvent. There is no attempt to improve rear legroom by making the car more upright and cab-forward, for example: the style remains the same, and the extra 21mm of room enjoyed by rear passengers comes out of a 30mm increase in the wheelbase.

Despite the 1-series’ limitations as a people-mover, three-door versions were always slow-sellers, and the new model is available only with five, at least at first. The new bodyshell, despite being hard to tell apart from the old one, really is new, with a wider use of high-strength, low-mass steels following widespread industry trends. The new body is 85mm longer at 4324mm, on a wheelbase of 2690mm. Overall width has increased by 17mm to 1765mm, while height remains unchanged at 1421mm. These figures compare with the Audi A3’s length of 4238mm (86mm shorter than the BMW), width of 1765mm (identical) and height of 1421mm (again identical). To complement the increased overall width, front and rear track widths are increased, by 51mm at the front and 71mm at the rear.

BMW’s Einser: new (top) and old.

Without quoting figures, BMW boasts that the new 1-series bodyshell has a high torsional rigidity. The load-bearing elements along the load-paths at the front, side and rear of the car make use of multi-phase and hot-formed steels.

Running-gear has been refined but retains the same layout as previously. At the front you will find a double-joint cross-strut layout; five-links locate each rear wheel. Electromechanical power steering is standard; the optional Servotronic function provides speed-dependent power assistance. Variable sport steering, also available as an option, reduces the number of steering wheel rotations required to make sharp turns. In this mechanical system, steering ratios are adjusted using a variable steering rack. Both the front and rear axles have double elastic bearings and extra-large bearing blocks for improved responsiveness; improvements in ride and handling are claimed compared with the earlier model.

Adaptive suspension is available as an option. The system’s electronically regulated dampers automatically adjust to the current driving style and road conditions. Their behaviour changes depending on which of the three ‘driving experience’ modes are selected — more anon. The adaptive suspension is 10mm lower than the standard setup, but this has allegedly no effect on the ride comfort when the car is running in Comfort mode.

For the first time, all 1-series engines are turbocharged, not just the diesels. There is a new generation of markedly undersquare 1.6-litre petrol engines, in two variants: the 116i has 136PS, the 118i 170PS. They are directly-fuelled and use BMW’s Valvetronic intake valve-control system with Vanos timing adjustment for both intake and exhaust camshafts. A twin-scroll turbocharger is used, with separate ducts both in the exhaust manifold and the turbocharger itself, each serving one pair of two cylinders. Valvetronic — the inspiration behind Fiat’s Multi Air system — uses the intake valves to control the amount of air required for combustion, minimising throttling losses during gas exchange.

Fuel is injected by magnetic-valve injectors with a maximum injection pressure of 120 bar, positioned centrally between the valves, directly next to the spark-plug.

The three diesels available initially all use a redesigned version of the familiar all-alloy 1995cc unit: the 116d offers 116PS, the 118d 143PS and the 120d 184PS. Also scheduled for launch soon is the BMW 116d Efficient Dynamics Edition, with a 116PS 1.6-litre diesel engine and additional fuel-saving technologies that will keep CO2 emissions over the E.U. rolling-road test cycle down to 99g/km; a provisional fuel consumption figure of of 3.8l/100km (74.3mpg) is quoted.

Modifications to the two-litre diesel family include reduced engine friction, new turbochargers with variable turbine geometry, and new magnetic-valve injectors. The dual-mass flywheel includes a ‘centrifugal-force’ [sic] pendulum to counteract vibration at low engine speeds.

A significant new feature to join the range is ZF’s excellent 8HP45 eight-speed epicyclic automatic gearbox, which is optional on all models. The standard transmissions are six-speed manuals. Interestingly — as we have seen with the C-class Mercedes — the more powerful engines fitted with the 8HP return better fuel economy figures than the six-speed manual variants: the small pumping losses of the automatic unit are more than offset by the superior ability of the eight-speed transmission to chase the engine’s torque curve, keeping crankshaft speeds closer to the ideal point for a given load condition. A sports version of the 8HP is available as an option on the 120d: this offers quicker gear-changes, and includes shift paddles on the steering wheel.

All versions of the new 1-series come with a stop-start system as standard. There is also an ‘Eco Pro’ driving mode — invoked using the driving experience switch — which adjusts the engine map, heating, air conditioning, and mirror/seat heating to minimise fuel consumption. The resulting notional increase in driving range is shown on a display. Eco Pro also provides prompts to help make driving more economical; these appear in the instrument cluster and, where fitted, the control display.

Fitted as standard, the driving experience switch on the centre console adjusts the car’s engine programming, the settings of the DSC (Dynamic Stability Control) and optional Servotronic, and the shift points and timing of the optional automatic transmission. On standard-specification models, there are three modes to choose from: Comfort, Sport and Eco Pro. On Sport Line models, and on cars fitted with the optional sports automatic transmission or variable sport steering, there is also a fourth mode, Sport+. Where the professional navigation system is fitted, drivers can see the current power and torque output of the engine on the control display: marginally less silly than most of the displays we see on these devices.

Energy management systems are used to cut fuel consumption. These include brake energy regeneration, the automatic disconnection of ancillary components and the adoption of electromechanical power steering.

Manual transmission models are fitted with an optimum gear-change indicator; a variable-displacement oil pump is used, along with a pressure/rev-regulated electric fuel pump, a self-disconnecting air-conditioning compressor and low rolling-resistance tyres.

Driver aids are numerous. Driving Stability Control includes Dynamic Traction Control and electronically ‘locking’ rear differential. ABS, Cornering Brake Control and Dynamic Braking Control are now augmented with braking assistance, fade compensation, brake drying and hill assist. DTC mode increases the intervention thresholds of DSC, making it easier to gain traction when driving on loose sand or deep snow; by allowing slight slippage of the drive wheels, it also facilitates controllable oversteer. DSC Off mode activates the electronic differential locking system: if either of the drive wheels suffers wheelspin while accelerating through tight bends, brake force is applied to this wheel individually, so that the opposite wheel maintains grip. (It is not actually the differential that provides the locking effect.)

A lane-departure warning with collision warning is available, as is speed limit information with No Passing information; these systems use a camera behind the rear-view mirror to read road signs and monitor the road markings. The camera also monitors the position of other vehicles and, if required, alerts the driver to danger. There are two levels of urgency to its warning: when a possible collision risk is first detected, a warning light comes on in the instrument cluster; and if evasive action is needed, the light flashes and an alarm sounds. We would have thought that the presence of the car in front would be more obvious than the warning light, but perhaps not.

Dynamic brake lights are a new feature. If the car brakes unusually hard, or the ABS system intervenes, the brake lights flash to warn following drivers.

Other equipment includes high-beam assistance, adaptive headlights, parking assistant, a rear view camera, cruise control with a braking function, internet connectivity, enhanced smartphone and music player integration, and real-time traffic information.

The adaptive headlight function is incorporated into the adaptive xenon headlight option. It adjusts the illumination depending on the vehicle’s speed, steering angle and rate of turn. At low speeds, the turning lights built into the fog lamps illuminate the road in the direction of travel. High-beam assistance is also included in the package. A rain sensor with automatic activation of the driving lights is also available.

Bosch’s park assistant is available: this effectively parks the car for you, using the electromechaniocal power steering motor, with the proviso that you have to operate the pedals yourself.

BMW Apps allow iPhone users to receive web radio stations and display Facebook and Twitter posts on the vehicle display. The new BMW Live function uses the data connection of the driver’s mobile to access selected content from the BMW Online service, including weather and news updates and Google Local Search. In conjunction with the Professional Navigation System and BMW Assist, the BMW Online portal provides more detailed information on the current route and destination, with weather reports, details of parking space availability and the Google Local Search tool, plus news, e-mail and address book functions.

Another new option is real-time traffic information. Available in conjunction with one of the optional navigation systems, this provides up-to-the-minute details of congestion on motorways, arterial roads and key urban routes. It suggests alternative routes, and recalculates journey times to reflect the current traffic conditions.

The new Einser is manufactured at BMW’s Regensburg assembly plant in Bavaria, alongside the 3-series, M3 and Z4. Shared processes for various models are used to raise productivity. The five-door version of the 1-series has been produced at Regensburg since the first generation went on sale in summer 2004. The Regensburg plant uses a ‘single-line’ system for both 1-series and 3-series models. This means that a single assembly line can produce 1-series, 3-series saloon, coupé and convertible, and M3 saloon, coupé and convertible models in any order.

Eco Pro display shows a notional gain in mileage by following the system’s guidance as well displaying a gauge showing the amount of engine power used or the rate of battery charging.

The fully automated painting line of the Regensburg plant sees the car bodywork undergo a multi-stage process. After cleaning, it is immersed in a cathodic dip tank, where it is turned and rolled to ensure even adhesion of the paint to the electrostatically-charged metal. Next comes the sealing of the panel joins and underbody spraying, followed by the application of first the primer and then the coloured topcoat layer: this is done by a high-speed rotary bell atomiser that operates at up to 40,000rpm. At this stage, too, the bodywork is electrostatically charged to ensure the most efficient possible use of the available paint, thereby minimising wastage and environmental impact.

The application of the fourth coat, the clear lacquer, involves a process for minimising the environmental impact of the the exhaust air. A combination of dry-scrubbing and air circulation reduces waste water production by four per cent. and energy consumption by four per cent. compared with conventional processes. Any overspray which does not adhere to the bodywork is blown onto filters coated with powdered stone, meaning no water is consumed in its disposal. The used powdered stone can be sold on for use as a raw material in the cement industry.

BMW UK expects to sell around 20,000 1-series five-door models in the model’s first full year. The most popular selling derivative in all versions of the previous 1-series was the 118d: in 2010, this engine accounted for 29 per cent. of three-door sales and 42 per cent. of five-door sales. In the coupé, 48 per cent. were 118d models, while it represented 36 per cent of convertibles.

BMW 116i 118i 125i 116d 116d ED 118d 120d 125d
Cylinders 4I 4I 4I 4I 4I 4I 4I 4I
Block/head Al/Al Al/Al Al/Al Al/Al Al/Al Al/Al Al/Al
Valves 4 4 4 4 4 4 4 4
VVT IE IE IE
Aspiration/
geometry
tsT tsT tsT T/v T/v T/v T/v 2T
Fuel
management
P
MEVD 17.2.5
P
MEVD 17.2.5
P
MEVD 17.2.5
D
D
DDE 7.01
D
DDE 7.01
D
DDE 7.01
D
DDE 7.01
Injection
pressure
12MPa 12MPa TBA 160MPa 160MPa 160MPa 180MPa 180MPa
Bore/stroke 77.0/85.8 77.0/85.8 84.0/90.1 84.0/90.0 78.0/83.6 84.0/90.0 84.0/90.0 84.0/90.0
Swept volume 1598cc 1598cc 1997cc 1995cc 1598cc 1995cc 1995cc 1995cc
Compression
ratio
10.5:1 10.5:1 10.0:1 16.5:1 16.5:1 16.5:1 16.5:1 16.5:1
PS/rpm 136/4400 170/4800 218/5000 116/4000 116/4000 143/4000 184/4000 218/4400
Nm/rpm 220/1350* 250/1500 310/1350 260/1750 260/1750 320/1750 380/1750 450/1500
Maximum speed 130 140 151 124 120 132 142 148
0-100km/h 8.5
9.1
7.4
7.5
6.4
6.5
10.3
10.7
10.5 8.9
8.9
7.2
7.3
6.5
6.5
Urban MPG
(l/100km)
39.2 (7.2)
38.2 (7.4)
37.2 (7.6)
38.2 (7.4)
32.8 (8.6)
34.4 (8.2)
52.3 (5.4)
51.4 (5.5)
64.2 (4.4) 51.4 (5.5)
51.4 (5.5)
50.4 (5.6)
54.3 (5.2)
47.1 (6.0)
49.5 (5.7)
Combined MPG
(l/100km)
49.6 (5.7)
48.7 (5.8)
47.9 (5.9)
48.7 (5.8)
42.8 (6.6)
44.1 (6.4)
62.8 (4.5)
62.8 (4.5)
74.3 (3.8) 62.8 (4.5)
62.8 (4.5)
62.8 (4.5)
64.2 (4.4)
57.6 (4.9)
58.8 (4.8)
CO2 g/km 132
134
137
134
154
149
117
119
99 118
119
119
116
129
126
Emissions EU5 EU5 EU5 EU5 EU5 EU5 EU5 EU5
Transmission
I

II

III

IV

V

VI

VII
VIII
Final drive
M6 (A8)
4.552 (4.714)
2.548 (3.143)
1.659 (2.106)
1.230 (1.667)
1.000 (1.285)
0.830 (1.000)
(0.839)
(0.667)
2.813 (3.077)
M6 (A8)
4.552 (4.714)
2.548 (3.143)
1.659 (2.106)
1.230 (1.667)
1.000 (1.285)
0.830 (1.000)
(0.839)
(0.667)
3.077 (3.077)
M6 (A8)
3.683 (4.714)
2.062 (3.143)
1.313 (2.106)
1.000 (1.667)
0.809 (1.285)
0.677 (1.000)
(0.839)
(0.667)
3.909 (3.077)
M6 (A8)
4.002 (4.714)
2.109 (3.143)
1.380 (2.106)
1.000 (1.667)
0.781 (1.285)
0.645 (1.000)
(0.839)
(0.667)
3.077 (2.647)
M6
4.002

2.109

1.380

1.000

0.781

0.645


2.929
M6 (A8)
4.002 (4.714)
2.109 (3.143)
1.380 (2.106)
1.000 (1.667)
0.781 (1.285)
0.645 (1.000)
(0.839)
(0.667)
3.077 (2.647)
M6 (A8)
4.110 (4.714)
2.248 (3.143)
1.403 (2.106)
1.000 (1.667)
0.802 (1.285)
0.659 (1.000)
(0.839)
(0.667)
3.154 (2.647)
M6 (A8)
4.110 (4.714)
2.248 (3.143)
1.403 (2.106)
1.000 (1.667)
0.802 (1.285)
0.659 (1.000)
(0.839)
(0.667)
3.385 (2.647)
Driven wheels Rear Rear Rear Rear Rear Rear Rear Rear
Fuel tank 52l 52l 52l 50l 52l 50l 50l 52l
Kerb mass † 1290
1310
1295
1315
1345
1365
1310
1345
1310 1320
1345
1390
1405
PS/t 105 131 162 88 88 108 136 156
Nm/t 170 193 230 198 198 242 282 323
Length 4324 4324 4324 4324 4324 4324 4324 4324
Width 1765 1765 1765 1765 1765 1765 1765 1765
Height 1421 1421 1421 1421 1413 1421 1421 1421
Wheelbase 2690 2690 2690 2690 2690 2690 2690 2690
Track
— front
— rear

1535
1569

1535
1569

1521
1556

1535
1569

1521
1556

1535
1569

1535
1569

1521
1556
CdxA 0.31x2.14 0.32x2.14 0.32x2.14 0.30x2.14 0.30x2.14 0.30x2.14 0.31x2.14 0.31x2.14
Brakes
— front
— rear

Dv
D

Dv
D

Dv
Dv

Dv
D

Dv
D

Dv
Dv

Dv
Dv

Dv
Dv
† DIN kerb mass. For E.U. kerb mass, add 75kg. Figures in blue are for automatic transmission models.
All fuel consumption and emissions data are for vehicles with 16" wheels.
* 116i with temporary overboost: 240Nm between 1500rpm and 3500rpm.
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