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2009 MINI technologies: what does what?

APN

16 January 2009.

Being part of the BMW group, advanced technology has to be an intrinsic part of the MINI culture, and one might add, of its jargon, at least in some aspects. In fact, MINI got the BMW passion for those resembling abbreviations, such as, CBC, DSC, DTC, in addition of course to the more common ABS, EBD... glossary.

This section aims to present the different technologies which were mentioned in the other pages of our presentation of the 2009 MINI range, rather than having them repeated with each version or model.

You will find here a more detailed explanation of the technologies related to engines or fuel saving, as well as comfort or active safety systems to help the driver correct handling surprises that might occur in bad weather, over bad road surfaces and / or due to a simple... adrenaline disorder.

Starting from the power unit, the four-cylinder petrol engine presented here is the 1,598 cc four-cylinder (joint development between BMW and the French group PSA, Peugeot - Citroën) which is made of light alloy and comes with the same bore and stroke, but with three different performance profiles: one in the MINI Cooper versions (normally-aspirated, 120 hp), another in the Cooper S versions (with turbo and direct gasoline injection, 175 hp), and the third in the MINI John Cooper Works versions (turbo and direct gasoline injection, 211 hp).

The various output, torque, consumption and emissions ratings can be found in the presentation of different 2009 MINI models. This page only presents the different technical terms encountered in the other pages.

This technology enhances turbocharger response and ensures a spontaneous build-up of engine power, virtually free of the “turbo gap” when accelerating. By separating the ducts of two cylinders at a time from one another in the exhaust manifold and the turbocharger, this approach reduces exhaust gas counter pressure at low engine speeds and benefit from the dynamic effect of the pulsating gas columns in the manifold.

Direct gasoline injection at BMW.

Illustration of the direct gasoline injection (BMW engine), with the fuel injector spraying directly in the combustion chamber (top right, with the spark ignition on the left side).

Applying the common-rail principle already known in the diesel technology, a stainless-steel common rail (connected to all injectors) is filled with fuel by a high-pressure pump at the rear-end of the intake camshaft. Injection valves positioned at the side of the cylinder head then receive the pressurised fuel from this common rail and deliver it within fractions of a second, in the most appropriate dose and timing, directly to the combustion chamber (unlike the traditional port-injection method, where fuel is injected and mixed with air before being sucked to the combustion chamber through the inlet valves). Four valve pockets and a combustion chamber trough positioned precisely in the middle of each piston help to provide optimum stratification of the homogeneous fuel/air mixture, to make the combustion the most efficient possible.

This BMW technology adapts the intake valve lift and the valve opening period to the power and performance requirements (engine load and driving conditions).

The camshaft acts on the valves not directly via a follower arm, but rather through an additional intermediate lever where the pivot point is adjusted infinitely by an electrically driven eccentric shaft. Changing over from minimum to maximum lift takes only about 300 milli­seconds – and at the same time valve timing is varied on both the intake and exhaust sides as a function of engine speed. This adjustment process is again infinite, with valve timing set to current driving conditions likewise within 300 milliseconds.

Interacting with one another, variable valve management and engine speed-related camshaft control optimise the torque curve and power output, to provide good torque right from the start at low speeds, while developing significantly more power than a conventional engine at high revs.

A further advantage offered by both technologies is the significant reduction of fuel consumption, which is further optimised by an oil pump with volume flow control and an electronically activated water pump for the coolant circuit, as well as the Brake Energy Regeneration (see next).

When the engine is pulling the car, this BMW technology automatically disconnects the generator (which converts mechanical energy, from the rotational movement here, into electric current).

In a conventional car, a certain part of the engine power is taken by the alternator to supply the necessary electrical needs of the car and to charge the battery. With the Brake Energy Regeneration, this partial power is not taken away from the engine if it is pulling the car, so the driver gets the most of the engine power for more dynamic acceleration, while contributing also to reduce fuel consumption and emissions.

The necessary supply of electric power to the car's needs remains guaranteed since the generator function is reactivated as soon as the car changes to overrun (gas pedal off), including when the driver applies the brakes.

In any case, the charge status of the battery is permanently monitored by the car’s energy management, to adapt the generator function to the real needs of the battery and to driving conditions and requirements, preventing automatic generator disconnection if necessary.

 Another fuel and emissions reduction measure comes from the Auto Start-Stop function, on all manual-gearbox versions. Depending on parameters such as ambient and engine temperature as well as the battery charge level, the Auto Start-Stop system switches off the engine automatically whenever it is not required, once the driver moves the gear lever to neutral and takes his foot off the clutch pedal, for example when stopping at the traffic lights. To start the engine again, the driver has to press down the clutch pedal: the engine automatically re-starts without the delay.

The Auto Start Stop function is activated immediately whenever the driver starts the engine, with the system becoming fully available as soon as the engine oil has reached the operating temperature required.

Permanently supervising the status of the car and weather conditions, the Auto Start-Stop control function is able to determine situations in which it is advisable to keep the engine running – for example where the battery is almost flat, in very hot (more than 30 °C) or low (less than 3 °C) exterior temperatures. The engine also keeps on running during short intermediate stops as long as the temperature inside the car has not yet reached the level set on the air conditioning or if heating power is required to de-ice or de-mist the windscreen.

The system is also able to distinguish between a short stop and the end of a drive, not starting the engine again automatically when the driver, with the engine switched off, opens his seat belt, the driver’s door or the engine compartment lid.

In any case, Auto Start-Stop may be deactivated whenever required at the touch of a button.

Gear Shift Indicator, to suggest the best gear to engage.

Gear Shift Indicator, to suggest the best gear to engage.

As a standard feature (check differences between markets or versions) on manual gearbox models (6-speed), this indicator (see opposite photo) helps reduce fuel consumption and emissions. The engine’s electronic control unit permanently analyses engine speed, driving conditions and the position of the gas pedal, to determine the best gear for economic motoring on the basis of this data.

As soon as it is appropriate to shift gears, an arrow symbol appears in the display beneath the rev counter and the ideal gear is shown as a numerical signal. The system takes into consideration the driver’s respective style of motoring.

The driver may activate or deactivate the gearshift point indicator through the on-board computer.

The Sports Button option serves to mastermind engine management, the steering and, when fitted, the 6-speed automatic transmission. Activating the sports mode at the touch of a button, the driver adjusts the gas pedal control map for a faster response, and even more direct steering response. On cars with automatic transmission, electronic management again helps to make the gearshift even faster.

For the front axle, MINI models adopt McPherson spring struts for their precise wheel guidance while at the rear, a multi-arm suspension offers optimum road contact through elaborate kinematics and the use of aluminium longitudinal arms to reduce weight to a minimum. Anti-rollbars contribute to reducing body sway. Suspension settings differ of course depending on the different models and versions.

EPS makes a significant contribution to agility, as power assistance is adapted to road speed, high assistance (less effort is needed to turn the wheel) in parking manoeuvres to much lower assistance (gradually) at higher speeds to enhance car stability and driver control.

But EPS also enhances the efficiency of the car with the electric motor only being activated and consuming energy when power assistance is really required or is desired by the driver. Comparatively, a conventional hydraulic power assistance system draws a certain part of the engine power, constantly, to keep the pressure high enough in the traditional hydraulic systems.

The new MINI models come with a set of active safety systems and functions to help the driver avoid an accident from happening (passive safety provides its protection once the accident happens): ABS anti-lock brakes, EBD Electronic Brake Force Distribution, CBC Cornering Brake Control, as well as DSC Dynamic Stability Control including Hill Start-Off Assistance (for standard or optional equipment, it is worth checking for differences between models, versions and markets).

DSC intervenes individually in the car’s brakes and reduces engine output to provide extra stability.

DSC intervenes individually in the car’s brakes and reduces engine output to provide extra stability, preventing under- or oversteering (left car in the graphic), as on slippery surfaces for instance.

When necessary, DSC intervenes individually in the car’s brakes and reduces engine output to provide extra stability, preventing under- or oversteering, as on slippery surfaces for instance.

The Brake Assistant, also included in the DSC package, recognises emergency braking and immediately builds up maximum brake power whenever necessary, keeping the car’s stopping distance as short as possible.

As an optionally available sub-system function, DSC offers DTC Dynamic Traction Control to allow carefully controlled slip on the drive wheels. MINI is the only car maker to offer this function on a front-wheel-drive vehicle.

To activate DTC, the driver has to press a button before setting off with the wheels slightly spinning – for example on a snow­bound road or loose sand – or approaching the car’s physical driving limits even more dynamically whenever required. Then, at a certain limit, DSC will cut in as usual also in the DTC mode. The driver can also completely deactivate DSC.

The Electronically Controlled Locking function is available as part of the DTC function. Referred to as Electronic Differential Lock Control, this system applies the brakes appropriately on a drive wheel spinning in a tight bend, to enhance traction without a negative influence on the steering behaviour.

DSC includes Hill Start-Off Assistance (also called Hill-Start Assist) that maintains braking for a brief moment after the hand-break is released, to allow a manual MINI to move uphill from standstill.

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