Development of the High Speed 2ZZ-GE Engine
The 1ZZ-FE, base engine to the 2ZZ-GE, was designed with the following targets.
1. To reduce exhaust emissions and improve fuel economy without extra systems. (i.e. direct injection)
2. To make compact and lightweight
The 2ZZ-GE was designed with the following additional targets.
1. Provide high speed performance
2. Retain low speed flexibility
3. Maintain same bore pitch as base engine
4. This was to keep the same outer dimensions
5. Maintain same emission standard as base engine Target TLEV
6. Achieve best power to weight ratio in the field
HIGH SPEED PERFORMANCE AND LOW SPEED TORQUE
The 2ZZ-GE adopted a Variable Valve Timing and Lift system called VVTL-i. The system changes valve timing over the entire speed range in accordance to engine speed and load. This feature is also used in the base engine. VVTLi also changes valve lift and event angles at 6000rpm from low to high. Table 2 shows the changes in valve timing and lift.
VVTi mechanism allows the valve timing of the intake cam to be changed continuously in the range shown. VVTL-i MECHANISM – The valve timing change mechanism of the VVTL-i system, VVT-i, has already been introduced in other papers. Figure 3 shows the schematic drawing of the lift change mechanism of the VVTL-i. Figure 4 shows the detail of the mechanism set inside the rocker arm.
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