Fig. 10 shows the characteristic output curve of the motor generator with the characteristics of the engine. The driving torque of the motor generator at low speed range is approximately 70% of the maximum torque of the engine. Regenerating braking torque within the range of practical use is more than equal compared to the engine braking torque. The efficiency in the diagram is the overall efficiency of the motor generator and the inverter including that of the reduction gear. High efficiency of more than 85% is achieved in the range over 1000 rpm.

Using the M15 mode (Fig. 11), which is generally used to evaluate fuel economy in the hybrid vehicle, a 26% reduction in fuel consumption and a 35% improvement in fuel economy are realized compared to a conventional diesel vehicle, which is no. 1 in its class. The reduction in fuel consumption is 8% with the idling stop during stopping and 21% with the power assist and Smoother-E Autoshift system during acceleration as shown in Fig.12. Fuel consumption during deceleration is increased by 3% because the engine is disconnected and idled, but the total reduction in fuel consumption is realized because much of the energy is recovered during deceleration.
Fig. 13 shows the fuel economy and improvement obtained in internal tests. Fuel economy in a diesel vehicle gets worse as the average speed decreases. This means when the average speed is low, the time the vehicle is stopping increases and fuel is consumed uselessly; frequent stopping and starting require more fuel. On the other hand, fuel economy in the hybrid vehicle does not change significantly from low average speed to high average speed. This means that fuel is not consumed uselessly when vehicle is stopped, and during deceleration and acceleration, regeneration and the assist minimize degradation of fuel economy. Accordingly, the hybrid vehicle has greater improvement in fuel economy and is suitable for applications that include low speed driving. We anticipate a 10 to 20% improvement in fuel economy for applications in urban areas, which is the primary target market of the Elf hybrid.

Certification as a Good - Low Emission Vehicle resulted from reducing NOx emissions by using the torque assist of the motor generator in the hybrid system and idling stop. Installation of the DPD earned certification as an Ultra-low PM Emission Diesel Vehicle (85% Reduction).

Fig. 14 Exhaust Emission