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The physical properties of ethanol make difficult the cold start of engines using only this fuel. The solution most adopted consists in the utilization of an auxiliary gasoline reservoir and the injection of this fuel when it is necessary. In this work, it is presented a new concept for the cold start system using gasoline injection that consisted in the use of a mini fuel rail, so called because of its compact layout that through the use of calibrated orifices allows the fuel injection as jets directly in the admission valves. It presents the CFD simulations, conducted to improve the system performance and the bench laboratory tests performed to evaluate the fuel distribution and to analyze the fuel jets.

In the current Brazilian air intake manifold market, most of the small car applications use the reinforced polyamide PA 6.6 GF30 as base material. The glass fiber (30%) guarantees the required mechanical resistance, necessary once the manifold is assembled on the engine and is subjected to considerable vibration levels. Air intake manifolds were developed using a new chemically recycled material recuperated from yarn production process, called Technyl ECO, which represents a reduction of 4.3 kg of CO₂ equivalent per 1 kg of polyamide produced. This material can replace the current one, once it has the same formulation (PA 6.6 GF30) and similar mechanical resistance. Moreover, it represents a cost saving up to 10% in the raw material. The air intake manifolds injected with the recycled material were subjected to the mechanical validation tests under severe conditions of accelerated aging at temperature of 140°C and thermal shock with abrupt temperature change from -40°C to 120°C.