Search Results

To meet the requirements for lower fuel consumption and emissions as well as higher performances, a “Variable Valve Timing - intelligent by Electric motor (VVT-iE)” system has been newly developed. The system has been firstly adopted to the intake valve train of the Toyota's new 4.6 and 5.0 litter V8 SI engine series. The VVT-iE is composed of a cam phasing mechanism connected to the intake camshaft and brushless motor integrated with its intelligent driver. The motor-actuated system is completely free from operating limitation caused from hydraulic conditions. This enjoys an advantage for reducing cold HC. The system also presents further reduction in fuel consumption.

The new generation engines currently being developed tend to require cold type spark plugs, which are prone to fouling. This paper describes the development of a new Coil on Plug ignition system that resolves this problem by using the high energy and the fast secondary voltage rise time of a capacitive ignition while maintaining inductive ignition characteristics for good ignitability. To evaluate the effectiveness of the system, spark plug insulation resistance was monitored and cold tests were conducted. The results demonstrated that the new ignition system is remarkably effective: insulation resistance remains high and startability and driveability are unaffected under conditions normally leading to excessive misfires and failure to start with a conventional inductive system. To satisfy environmental concerns, automobile manufactures are increasingly turning to high compression ratio engines in view of their improved performance.