A fourth actuator is linked to the engine’s electronic throttle and manages torque flexibly on the basis of requests received through the gearbox control system.
The time taken to change gear is measured from the beginning of torque discharge to the end of torque return. With a conventional manual gearbox, this operation (typically) takes one to one-and-a-half seconds. Selespeed gearchanges take a similar amount of time when the vehicle is driven normally. However when the driver starts to press-on, (i.e. the accelerator is depressed through more than 60 per cent of its travel and engine speed is maintained at about or above 5000 rpm), the system shifts gear in half the time: 4-5 tenths of a second - less time than a top test-driver would take using a conventional manual gearbox. But the system prevents over-revving, because if the driver hesitates too long, the gearchange is made automatically.
Selespeed thus makes it possible to push the car’s overall dynamic abilities to the limit without altering engine performance in any way. The driver can shift gears neatly and accurately while keeping both hands on the steering wheel, and without having to use a clutch.
Emphatically sports-orientated when required, but also easy to exploit and to live with, Selespeed can work in two modes: semi-automatic and automatic. In the latter, when the ‘City’ button is pressed, gear shift controls and decisions over which gear to be engaged are delegated to Selespeed, and the driver is left free to enjoy a relaxing drive that is particularly appreciated in town.
Selespeed incorporates a hydraulic power system. An electric pump takes oil from a reservoir to an actuator that generates pressure in the circuit and provides the energy required to move the clutch engagement and disengagement levers, to select gears, and operate the clutch itself. Because the system needs energy from start-up, the pump begins to operate as soon as the driver’s door is opened. The circuit has already reached the required pressure by the time the car is ready to be driven away.
Fuel supply is governed by a dedicated electronic control unit, manufactured by Magneti Marelli. The control unit communicates continuously with the Bosch Motronic unit that manages the engine, and is responsible for processing the driver’s requests and converting them to gearchange commands. To do this, the control unit utilises information such as accelerator pedal position, vehicle speed, engine rpm and torque input. The system is also supplied with data by sensors and potentiometers located at specific points of various drive components, which it also uses to monitor component service status.
The steering wheel is fitted with two buttons: an ‘up’ control on the right hand side (identified by a ‘+’ sign) for sequential gearshifts during acceleration; and a down control (identified with a ‘-’ sign) on the left for changing down during deceleration. The lever works in the same way: it is shifted in the direction of motion to change up, and towards the rear of the car to change down. A ‘City’ control on the transmission tunnel is used to activate automatic mode. The steering wheel or gear lever controls are no longer required when this mode is selected. A VDU inset into the rev counter indicates which gear is engaged, ‘City’ mode, or system faults.
THE DRIVING EXPERIENCE
To start the car, the brake pedal is depressed and an appropriate gear engaged by the driver to set off: first, second or reverse. The gearlever on the transmission tunnel is used for this operation, because the steering wheel controls are not active at speeds below 6 mph. The brake is then released and throttle applied to accelerate the car. Once it is travelling at 6 mph, the driver can change gear using the steering wheel controls, or continue to use the sequential lever. The latter takes priority if both controls are operated at the same time. The driver can keep the accelerator pedal depressed during gear changes, although smoother shifts can be ascertained by ‘feathering’ the throttle momentarily during changes. Selespeed controls the engine directly to reduce and then increase torque and adjusts rpm to the next appropriate gear, but gear shift commands are accepted only if compatible with maximum and minimum rpm limits.
Actuator control sequences are also equipped with a time-out function, which allows the command to be repeated if it is not initially successful. The system will attempt to engage the required gear, but if this is not possible, it immediately selects a higher gear so as not to leave the car in neutral. During emergency braking manoeuvres, the system detects the rate at which engine speed is dropping (rpm are directly linked to vehicle deceleration because the clutch is still engaged) and automatically changes down through the gears. This operation is carried out only in the case of sudden heavy braking manoeuvres: the system does not replace the driver, but intervenes solely to ensure greater safety. When the driver opens the throttle to its maximum and pushes the car in a low gear to maximum rpm, the system shifts up a gear by itself. The same thing does not happen, however, if the accelerator pedal is not pressed. In this case, Selespeed recognises that the car is on a downhill gradient and automatically engages the clutch once a set speed has been reached, so as to increase engine braking. Control of the car is restored to the driver when the accelerator is pressed again.
Enthusiasts will soon come to appreciate that the new transmission ‘double-shifts’ automatically, the electronics perfectly matching engine rpm to road speed, resulting in high quality seamless changes that sound and feel perfect, complete with an accurate throttle ‘blip’, as though the driver had executed an immaculate ‘heel-and-toe’ gearchange. When the driver releases the accelerator at the approach to, say, a cross-roads or traffic light, Selespeed detects an intention to slow right down and automatically shifts down and releases the clutch to prevent the engine stalling. If the driver intends to start off again without stopping completely, the system automatically engages the best gear for pulling away. Selespeed automatically engages first gear when the car stops. To engage neutral with the car at a standstill, the driver presses the brake and pushes the gear lever to the right. If the accelerator and brake pedals are not touched for one minute, the gearbox automatically makes the same shift. For safety reasons, the driver is prevented from engaging neutral at speeds greater than 25 mph. A gear must be engaged before the driver can switch off the engine and remove the ignition key. If the key is turned to ‘off’ with the gearbox in neutral, a warning buzzer sounds.
A gear must be engaged before the driver can switch off the engine and remove the ignition key. If the key is turned to ‘off’ with the gearbox in neutral, a warning buzzer sounds. The system deactivates itself two seconds after receiving a zero speed signal from the engine and the gearbox input and output - and also after saving operational and test data in the control unit’s permanent memory. Selespeed automatically shifts to neutral when the car is restarted.
Selespeed thus boasts a series of features designed to prevent the driver making incorrect commands that could create dangerous situations or damage mechanical components.
- The engine may be started with a gear engaged or in neutral. In any case, when the brake pedal is pressed and the accelerator pedal released (condition required for start-up), the system automatically engages neutral.
- The brake pedal must be depressed in order to engage a gear when the car is at a standstill. This prevents the lever from being operated involuntarily by either passengers or driver.
- With the car at a standstill and the engine running, only first, second or reverse gears are accepted.
- When speed is lower than 6 mph, the steering wheel push-buttons are disabled. This prevents possible driver errors during parking manoeuvres.
- If two gearshift requests are made simultaneously using steering wheel buttons and gear lever, the gear lever command takes priority.
- A reverse gear engagement command is not accepted if the car is moving.
- Gearshift requests are not accepted if they would increase or decrease engine rpm to levels beyond the maximum permitted range.
The gear ratio is changed automatically when the driver continues to push the engine beyond its limits without changing gear. This does not happen if the accelerator pedal is not pressed to the floor, as the system detects a downhill gradient.
- Commands for neutral are not accepted at speeds greater than 25 mph, to prevent incorrect commands being issued in critical situations (such as during descents or overtaking).
- The gearbox is shifted to neutral automatically and the driver notified by a buzzer when:
- with the engine running, the driver’s door is open and neither accelerator nor brake have been pressed for at least one second (e.g. if, as sometimes occurs, the door is held open during a difficult parking manoeuvre);
- with the engine running, a gear is engaged and neither accelerator nor brake are pressed within one minute;
- oil pressure is too low to operate the clutch.
- ‘City’ mode is cancelled when the driver selects a gear directly, using gearlever or steering wheel buttons.
The driver is also kept up-to-date on system operation and informed when a gear change is impossible. For example, reverse engagement is indicated by an acoustic and visual signal, and another signal notifies the driver when the engine is switched off and the gearbox is left in neutral. A warning light also comes on when transmission oil pressure is too low, and an intermittent sound warns when the clutch is slipping. Selespeed is also able to test automatically for faults in its components.
156 SELESPEED SPECIFICATION
The Alfa 156 Selespeed is based on the 2.0 Twin Spark version, but differs from it in a number of ways.
Visually it is easily distinguished by a set of exclusive 16-inch alloy wheels which are part of the Selespeed’s standard equipment.
There is a Selespeed badge at the rear, and inside, there is a new design of leather steering wheel with integrated gearchanging controls, and a VDU set in the tachometer indicating which gear is engaged. In addition, a carbonfibre coloured central console is standard equipment. Three Sport Packs are available as options.
ALFA ROMEO (GB)
Alfa Romeo (GB) looks forward to the coming year with confidence, following a 51% increase in its business last year (year-on-year). This impressive sales result was achieved on the back of 156’s continued huge success. The recipient of some 33 media awards - including Car of the Year 1998 - since it went on sale less than 18 months ago, more than 200,000 156 versions have now been ordered, and it accounts for about 60 per cent of all Alfa’s European sales.
Available in 66 countries, including Australia where Selespeed is also poised to go on sale, Alfa 156’s success continues to be reflected in the UK, where just under 5000 units were sold here in the car’s inaugural year. The new Selespeed version brings additional muscle to the range, which is set to expand further in the near future.