Intake System Design Approach for Turbocharged MPFI SI Engine

The automotive industry is currently facing the challenge of significantly stringent requirements regarding CO₂ emission and fuel economy coming from both legislations and customer demand. Advanced engine technologies play a vital role for downsizing of gasoline engine. The development of key design technologies for high efficiency gasoline engines is required for the improvement of competitive power in the global automobile industry. This paper focused on effect of geometry of intake manifold of gas exchange process and consequently the performance of the engine. Specially, the optimal design technologies for the intake manifold and intake port shape must be established for high performance, increasingly stringent fuel economy and emission regulations. Space in vehicle or packaging constraints and cost are also important factors while consideration of the design.

Two models of intake manifolds discussed in this paper, such as short runner intake manifold and long runner intake manifold with different plenum chambers. Parameters like manifold plenum volume, runner length affecting dynamically on gasoline turbocharged engine performance are studied and evaluated. By employing these parameters, performance prediction of 2.2-liter MPFI Turbocharged Gasoline Engine is done by using mathematical models made from AVL Boost 5.1 software. CFD simulations are conducted on the both proposal to examine the distribution of the air flow from plenum to individual runners. Actual test bed engine performance is predicted and compared with boost performance. Injector position is defined on last section of primary pipe or runner in order to maximize fuel vaporization. The fact, fuel should not be injected on port walls and accordingly angle has been confirmed by injector target test.