DeKa said:
Daniel,
Whatcha talking about?
The gearbox is a shared Renault/Peugeot/Citroen unit. It was co-developed between the three car companies and Siemens. In Renault-speak it's called the DP0 (that's a zero). In PSA speak it's called the AL4.
The gearbox is definately used in all 4 cylinder Peugeots, Citroens and Renaults. I'm not too sure about 6 cylinder engines, but if it's up to the torque figures that V6's put out, it would be.
Most people who whinge when they first buy the car seem to be very happy with it after they get used to it and see the benefits of an auto box which changes down gears as you slow down.
Derek
Thanks for the advice on the AL4 - I Googled it & found this interesting rave from UK. I wonder how long before smartarse computer geeks start reprogramming the controls?:
Automatic gearboxes are finding favour all around the world, with about 44% of cars worldwide using them. In Europe, according to Renault, this figure is 8% but expected to grow. In the US, 90% of cars are already so equipped and in Japan almost 80% of cars have an automatic transmission.
Automatic 307s are equipped with the latest version of the AL 4 gearbox, which is also used in many other Peugeot models, including the N5 306, 206, 406 and 807. The AL4 was developed in conjunction with PSA partner Citroen, Siemens and Renault (DP0). PSA and Renault shared the development costs of 2.75 billion French francs (about 410 million USD) in 1997. It weighs 70kg, and can handle up to 330Nm of torque (210Nm on earlier versions). Hydraulic torque converter lock up is available on 2nd, 3rd and 4th gears. Transmission oil is cooled by a heat exchanger. The Gearbox ECU uses 40 channels, which sends and receives information from the engine ECU via the CAN network. Peugeot claims the fuel consumption increase with this gearbox over the manual equivalent is small - in the 307 1.6, there is only a 0.2l increase for every 100km driven on the city cycle (AS2877).
In normal mode, the transmission is auto-adaptive, that is, it tries to shift according to your driving pattern. It considers the vehicle load, road gradient and surface, the speed of accelerator actuation and other factors such as gearbox oil temperature and engine temperature. The computer creates an identikit portrait of the driver within a minute, considering the speed of the car, the number of times and the speed at which the driver presses the accelerator (and its position). From this the computer categorieses the driver as being in an economical, sporting or medium category. These categories correspond with a set of gearshift rules which favour either economy, performance or a compromise between the two, which is determined from an average of values over the past few minutes. This can be temporarily changed if the accelerator is pressed rapidly - the ECU will select the next sportier program (ie. from ECO to MEDIUM or MEDIUM to SPORT) - upon release, the transmission resumes the earlier mode.
Normal Mode Pattern Selection - Table
Vehicle Driving Conditions
(this is supposed to be a table)
Driving Conditions Downhill Level Ground Average Ascent Steep Ascent
ECO Pattern DESCENT Pattern ECO Pattern BRAKING Pattern 1 BRAKING Pattern 2
MEDIUM Pattern DESCENT Pattern MEDIUM Pattern BRAKING Pattern 1 BRAKING Pattern 2
SPORT Pattern SPORT Pattern SPORT Pattern SPORT Pattern BRAKING Pattern 2
There are 6 'laws' from which the transmission can choose in auto-adaptive (normal) mode. ECO Pattern and BRAKING Pattern 1 are the most common modes used. Two additional modes can also be manually selected.
Sports mode automatically limits the transmission to the two most dynamic/sporty/aggressive modes. In sports mode, the cars holds onto gears longer, will not shift into 4th gear until high speeds (ie. +100km/h) and shifts down eagerly to provide engine braking (both under brakes, and when slowing down without brakes). It is also slightly less eager to lock up the torque converter. Sports mode is very effective for sporty driving, more so than most other automatic transmissions, as the torque converter is locked up, and hence engine braking is also provided - which is noticeable under braking. The aggressiveness of downshifting under braking depends on factors such as the gradient and the amount of braking applied by the driver.
In Snow mode the car starts off in second gear, so as to reduce the likelyhood of wheelspin. The transmission will have fewer gearchanges, will not kickdown unless below 15 km/h, and will force downshifts on application of braking. This is the only mode not selected by the auto-adaptive system.
In addition to the aforementioned automatic modes, the AL 4 in the 307 is also equipped with a Porsche Tiptronic system (manual mode). The driver can manually change gears (without clutch), by pushing the gearstick forward to upshift, and to downshift by pulling back on the shift lever. The system will not allow any potentially hazardous shifts to take place - it will not allow a downshift if it will overrev the engine. Conversely, it will also upshift when engine revs are too high. In addition, when too high a gear is selected (eg. 4th gear at low speeds), the engine will either unlock the torque converter or downshift to prevent the engine from stalling. In total, the AL4 has 10 modes.
In the interests of safety, theoretically the transmission will not upshift if the accelerator pedal is suddenly released. Peugeot claims it is sealed for life, requiring no fluid changes. However, the transmission has an oil wear counter, allowing 6000 hours of operating at oil temperatures below 95°C (32,958 units of wear). Using Diag2000, a technician can determine whether the fluid requires changing.
When the transmission is cold (<15°C), the torque converter lock up plate is too hot or has a fault, the torque converter will remained unlocked to warm up the fluid to 15°C. Upon reaching this, the gearbox heating pattern begins which helps to heat the engine and catalytic converter, reducing exhaust emissions (it certainly seems effective as the engine warms up very quickly, which means fast cabin heating). There is also a overheating protection pattern, which has maximum priority over other modes to cool down the transmission fluid - it begins operation at 120°C, and ceases at 110°C.
The AL 4 can be quite a clever unit. I have found that it provides excellent fuel consumption, fuel consumption not much greater than the manual version. However, the acceleration in the automatic feels much more sluggish than the manual 1.6 and at times the logic is questionable.
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