| Mazda Motor Corporation has unveiled a new direct injection 2 litre
turbo diesel engine which the company considers to be one of the most effective
technologies for helping to solve global environmental problems. Designed for clean combustion and high economy operation, the new compact
diesel engine uses a highly fuel-efficient direct injection system.
The result is a smaller engine size, reduced combustion noise and
NOx emissions similar to the level of indirect (pre-chamber) fuel injection diesels,
making it an ideal diesel engine for passenger cars.
This compact, 1,998 cc turbocharged diesel generates a maximum
output of 100 ps at 3,500 rpm (target), and a maximum torque of 220 Nm at 2,000 rpm
(target). This is a 14 percent and 18 percent increase, respectively, over the
conventional engine on which it is based. This new diesel engine scores an impressive 5.2
L/100km fuel consumption rate at 120 km/hour (target).
The advanced diesel also has a new combustion system that employs
innovative centre fuel injection technology, a four-valve-per-cylinder design and an
electronic fuel injection system which places the fuel injection nozzle at the centre of
the combustion chamber to inject fuel uniformlv
These features give this engine the quick ignition of indirect
injection engines at the start of combustion and the high pressure fuel-air combustion of
direct injection engines during the main propagation period.
The system also improves fuel atomisation for better ignition,
inhibits rapid combustion at the start of the combustion cycle, and reduces noise and NOx
emission. Fuel is also distributed more uniformly promoting even combustion and improving
output.
Each cylinder has two intake and two exhaust valves to increase the
air intake to the engine and decrease resistance to exhaust flow. This design improves the
intake-exhaust resistance coefficient by approximately 50 percent compared with
conventional two-valve technology. Output is improved and black smoke and particulate are
also reduced because the fuel is burned with more air.
The electronic fuel injection system constantly monitors changes in
vehicle operation including the accelerator position and vehicle speed. to optimally
control the amount and timing of fuel injected.
Noise and Nox emissions are reduced under partial engine load
conditions because the fuel injection timing is delayed according to the load, thereby
improving combustion.
From outside a vehicle, the new engine is "seen" to be
cleaner because under full load conditions, the amount of fuel injected is maximised
without increasing black smoke.
The new direct injection diesel engine will be fitted to Mazda 626
vehicles in Japan and Europe from mid 1998.
Major Specifications
Type: In-line 4-cylinder, 16Ävalve, water cooled, with turbocharger
Displacement (cc): 1,998
Bore x stroke (mm): 86.0 x 86.0
Max. output (ps/rpm): 100/3,500 (target)
Max. torque (Nm/rpm): 220/2,000 (target)
Fuel supply system: Electronically-controlled fuel injection |
