Power densities are similar to those of a naturally aspirated
gasoline engine. The engine may produce 80 kW per liter of
power and 150 Nm per liter of torque running ultra-lean
V¼ 0.43 with knock index and BSNOx within acceptable levels.
Brake efficiency figures predicted are over 40% and greater
than 35% over most of the load-speed map running V¼ 0.43–
0.28. The energy efficiency deteriorates as the fuel-to-air
equivalence ratio reduces, but efficiencies of about 30% are
still possible at conditions important in urban driving (low
speed and load) even V¼ 0.18.