Porsche 911 Carrera 4 Brochure & Specs page 19

Why it always pays
to take the direct route.
The engine of the 911.
All 911 models feature direct fuel are outstanding performance and
injection (DFI). The 3.6-litre surprisingly low fuel consumption
horizontally-opposed engine and emission values. All made
generates 254 kW (345 hp), and possible thanks to DFI, VarioCam
the 3.8-litre version has an output Plus, a lightweight construction,
of 283 kW (385 hp). The results low friction and a number of
detailed technical solutions.
3.8-litre boxer engine
Direct fuel injection (DFI).
With millisecond precision, DFI
injects fuel at up to 120 bar
directly into the combustion
chamber by means of electro-
magnetically actuated injection
valves.
The spray and cone angles have At up to 3,200 rpm, the engine
been optimised for torque, power operates with dual injection; at
output, fuel consumption and up to 2,500 rpm, it even works
emissions by enabling a homoge- with triple injection. The required
neous distribution of the air/fuel volume of fuel is distributed
mixture, and, therefore, effective between two or three sequential
combustion. With direct injection, injections, respectively – for faster
the EMS SDI 3.1 engine control heating of the catalytic converters
regulates injection timing individu- after a cold start and for greater
ally for each cylinder as well as torque in the upper load range.
the injection rate for each cylinder
bank. This optimises the combus- DFI improves the internal cooling
tion process and fuel economy. A of the combustion chamber by
hot-film air mass meter takes care having the mixture prepared
of the airflow, so that the combus- directly in the cylinder. This allows
tion chambers contain exactly the for a higher compression ratio
right mixture at all times. (12.5:1) which helps to deliver
The 911 |
Engine
more output along with enhanced
engine efficiency. It has been
possible to reduce CO emissions
2
by up to 15 % compared with the
previous model.
Injection is regulated by the
electronic engine management
system. The exhaust gas cleaning
system ensures that emissions
remain well below even the
strict limits of the Euro 5 emission
standard, thus helping to protect
the environment.