30 YEARS of ALL-WHEEL DRIVE in the 911
All-wheel drive concepts – Driving dynamics Lateral grip potential at the rear axle at the limit oversteer All-wheel drive concepts – Driving dynamics Lateral grip potential at the rear axle at the limit oversteer Circle of forces
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front axle rear axle All-wheel drive concepts – Driving dynamics Torque transfer to the front axle counteracts oversteer Circle of forces
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front axle rear axle All-wheel drive concepts – Driving dynamics Torque transfer to the front axle counteracts oversteer All-wheel drive concepts – Driving dynamics Lateral grip potential at the front axle at the limit understeer All-wheel drive concepts – Driving dynamics Lateral grip potential at the front axle at the limit understeer Circle of forces
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front axle rear axle All-wheel drive concepts – Driving dynamics Torque transfer to the rear axle counteracts understeer Circle of forces
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front axle rear axle All-wheel drive concepts – Driving dynamics Torque transfer to the rear axle counteracts understeer 1988: Porsche 911 Carrera 4 (964) Permanent all-wheel drive with centre differential 1988: Porsche 911 Carrera 4 (964) Permanent all-wheel drive with centre differential
• Variable drive torques at FA and RA • No tension in the axles when cornering
• Driving dynamics can be influenced only to a limited extent • Centre differential initially distributes drive • Controllability limited due to technology torque at a fixed ratio between RA and FA and computing capacity (69:31) • Use of variable multi-plate locks as centre differential and rear differential locks allows Traction Stability Agility Driveability the distribution of drive torque within set limits • Additional braking control ABD (automatic brake differential) 1994: Porsche 911 Carrera 4 and 911 Turbo (993) Variable all-wheel drive with viscous coupling
1994: Porsche 911 Carrera 4 and 911 Turbo (993) Variable all-wheel drive with viscous coupling
• Good traction compared to rear-wheel drive • Switches on independently when there is a difference in speed between FA and RA
• No decoupling of drive from axles and • Engine drives rear axle directly wheels (for instance, when the brakes are • In the event of slippage between the two axles applied affects control systems such (spinning rear wheels), the viscous coupling as ABS and ESP) closes and directs torque to the front axle Traction Stability Agility Driveability • Additional braking control ABD (automatic brake differential) 2006: Porsche 911 Turbo (997) Controllable all-wheel drive with electro-magnetically actuated multi-plate clutch
2006: Porsche 911 Turbo (997) Controllable all-wheel drive with electro-magnetically actuated multi-plate clutch
• Good controllability of driving dynamics and traction • Map control enables predictive and situation- dependent torque distribution • Low system weight
• Engine drives rear axle directly • The multi-plate clutch is activated depending on • Cost the driving situation and distributes the torque • Complexity fully variably between the front and rear axles
• Porsche Torque Vectoring (PTV) with variable Traction Stability Agility Driveability rear-axle differential lock • Additional braking control ABD (automatic brake differential) and TC (Traction Control) 2013: Porsche 911 Turbo (991) Controllable all-wheel drive with electro-hydraulically actuated multi-plate clutch
2013: Porsche 911 Turbo (991) Controllable all-wheel drive with electro-hydraulically actuated multi-plate clutch
• Good controllability of driving dynamics and traction • Fast response and excellent adjustability • Pre-controllable via map control • Low system weight • Engine drives rear axle directly • New electro-hydraulic actuation of the multi- plate clutch • Cost • Porsche Torque Vectoring (PTV) with variable • Complexity rear-axle differential lock • Additional braking control ABD (automatic brake Traction Stability Agility Driveability differential) and TC (Traction Control) All-wheel drive concepts Overview
Brake Year/Type All-wheel drive system control Traction Stability Agility Driveability 1988/964 Centre differential with multi-plate lock ABD Carrera 4 Controlled rear-axle differential lock 1994/993 Hang-on front axle (passive) ABD Carrera 4 Viscous coupling 1998/996 Hang-on front axle (passive) ABD, TC Carrera 4 Viscous coupling Hang-on front axle (active), 2006/997 electro-mechanically controlled ABD, TC, PTV 911 Turbo multi-plate clutch, controlled rear-axle differential lock Hang-on front axle (active), electro- 2013/991 hydraulically controlled multi-plate clutch ABD, TC, PTV 911 Turbo with increased torque, controlled rear-axle differential lock