To comply with the environmental demands for CO2 reduction without compromising driving performance, a new 1.0 liter I3 turbocharged gasoline direct injection engine has been developed. This engine is the smallest product in the new Honda VTEC TURBO engine series (1), and it is intended to be used in small to medium-sized passenger car category vehicles, enhancing both fuel economy through downsizing, state-of-the-art friction reduction technologies such as electrically controlled variable displacement oil pump and timing belt in oil system, and also driving performance through turbocharging with an electrically controlled waste gate.
This developed engine has many features in common with other VTEC TURBO engines such as the 1.5 liter I4 turbocharged engine (2) (3), which has been introduced already into the market. Some of these are the rapid combustion concept realized by high tumble intake port design and the optimized combustion chamber configuration combined with a side mounted multi-hole direct injection system.
In addition to VTC (valve timing control system), the VTEC (Variable valve timing and lift electronic control system) has been used in the intake valve system in order to realize an Atkinson cycle to reduce fuel consumption in low valve lift mode. Investigation results show that side-mounted direct injection has potential comparable to that of central-mounted direct injection in terms of mixture homogeneity and combustion chamber wall wetting, while no disadvantage in combustion performance was observed.
Through such technologies, this developed engine achieved top level of fuel consumption characteristics in this class, contributing to improve the fuel economy by 26% from the previous engine in NEDC (new European driving cycle) mode.