Recent drastic drop by 50%, vs. a year ago, in sales of the Toyota Prius hybrid car coincides with launch in the EU of the Auris powered by an advanced engine and system that is more affordable than the hybrid yet more fuel efficient than prior non-hybrid systems. While first use is in the Auris, Toyota indicates the new system is destined for use in both smaller and possibly larger models..
Toyota’s new system for the Auris, called “optimal drive”, includes a unique 1.33L dual variable valve long stroke engine, 6-speed manual transmission and automatic stop/start feature applied initially to the 102 inch wheelbase Auris.. 40.6 MPG is achieved per the EU test which compares with 34.1 MPG for the Auris with a standard 1.4L engine, hence, a 19% fuel efficiency gain for the 1.33L system . The Auris car is 2.4 inches wider, 1.4 inches taller but 12 inches shorter yet has the same wheelbase of the current US Corolla model which it may replace. .
The higher priced Prius is a recent victim of the drop in US gasoline prices(hence long pay-back period). Tax credits granted to Prius hybrid buyers have ended. It also reflects severe down turn in the US economy with negative impact on more expensive car models..
Toyota’s introduction of an affordable, less complex car technology such as the 1.33L Auris could hardly have been better timed since government agencies are now stepping up efforts to seek increased motor fuel taxes.to offset revenue losses from other tax sources and need for development of alternative fuels for national security, domestic economy and environmental reasons.
Information released by Toyota on its new 1.33L engine and system follow:
The 1.33L 4-cylinderAuris engine is 54mm shorter, 127mm narrower and has
the same volume as a 3 cylinder, 1.0L engine. This will be a key advantage for use in Toyota’s new architecture cars which have less space for the powertrain..
Output of 101 HP and 132 Nm torque @ 3800 RPM, are marginally better than its
1.4L counterpart yet fuel economy is 19% improved.(if the system replaces larger
engines up to1.8L, for instance, the MPG gain may be greater). ..
Piston weight has been cut 36% from 280 grams to 180 grams with consequent energy saving..Pistons are cooled with oil jets which permit more efficient lean operation.
Resin intake manifold and engine cover reduce weight. Intake passages are optimized for air flow efficiency.with smoother surfaces and rounded corners. .
Dual continuously variable intake and exhaust valves optimize both efficiency and
normal use driveability. The better efficiency of variable compression ratio long
sought by engine engineers is effectively achieved.
The 6-speed manual transmission has 15% fewer parts and is 11% smaller than the
previous 5-speed unit..
The engine shuts down when the vehicle stops and transmission is put in neutral. The engine restarts within 0.4 seconds following clutch action. The starter motor is in direct contact with the ring gear at all time. Noise is reduced
Toyota has indicated that the 1.33L engine is planned for use in the IQ small car and possibly also in other cars but has not indicated its plans for the U.S.market. Regardless, the competitive race is on among car makers to produce affordable cars with ever greater fuel efficiency.
Toyota’s “optimal drive” 4-cylinder engine bears witness to the long held belief of
most automotive engineers that the end of the Otto piston engine era is a long way out in the future.