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The efficiency of engine operations, i.e. cold start, transient response and operating at idle, depends on the capability of the injection fuel system to promote a homogeneous mixture formation through an efficient interaction with engine fluid dynamics and geometry. The paper presents the development and the application of a methodology for running a CFD PFI engine simulation. A preliminary assessment of the wall-film and droplet-wall interaction sub models has been carried out in order to validate the methodology. Then a three-step numerical procedure has been adopted. The first two steps are aimed to properly initialize the secondary breakup model depending on the type of injector installed on board in order to achieve accurate predictions of spray characteristics.

A very stringent problem in most of European cities is the individual mobility. This problem is mainly caused by traffic jam and arising from this are two particularly interesting environmental issues: pollution and noise [1]. Use of two wheeler vehicles does not represent the final solution to these problems, nevertheless they can supply a useful aid to ease them. Recently, two stroke engines are being replaced with four stroke engines. For small capacity engines this means a true reduction in exhaust emissions, especially unburned hydrocarbons (HC), but, on the other hand it involves a performance reduction, particularly for sudden accelerations, which constitute an essential requirement for these vehicles [2, 3, 4, 5]. Hybridisation can help to fill the gap between two stroke engines and cleaner, but less performing four stroke engines [6]. At the same time, it can help to lower fuel consumption, by means of a reduction in the revolution speed [2, 5].

Recently Piaggio developed a new scooter equipped with a revolutionary front suspension electronically controlled locking. It was critical to test and validate the design of this new control system before deployment to ensure high customer satisfaction and reducing warranty costs. Test on a HIL platform accelerates the verification and validation process. A validated HIL set-up, being a repeatable and reliable test platform with a short turnaround time is ideal for developing standardized processes for Electronic Control Unit (ECU) testing and calibration. With shortening life cycles in the motorcycle industry, HIL technology is rapidly gaining acceptance not only in conventional vehicle programs, but also challenging vehicle programs. The development of control strategies for MP3 ECU has benefited from HIL-based testing. It has proven to be an efficient tool for software strategy development, implementation and validation.

This paper presents a method, based on multibody analysis, developed in order to reduce the time required to get the optimum design choice in terms of ride comfort behavior. The model that has been built has 4 degrees of freedom, besides the vehicle translational degree of freedom. This model has been defined in a parametric form to allow an easy conceptual design development. The virtual vehicle rides over a reproduction of a real rough road profile, properly selected to emphasize ride comfort characteristics of the scooter. It is possible to ride at different speeds, simulating the most significant ride conditions. Using this model, the engineers involved in a new design can simulate in advance to prototype manufacturing, the effect of geometric and functional changes in suspension characteristics (like what happens changing the location of engine suspension links to the scooter frame, front fork geometry, stiffness and damping characteristics of shock absorbers and so on).

0 In this work we illustrate a data acquisition system realization and set up for the experimental description of an air cooling system for a four stroke, one - cylinder engine used on scooters. The high importance of the power absorbed by cooling system at medium and high rotational speeds is the first reason of this investigation, our target is to point out possible increasing in the forced ventilation cooling system performances. First of all, in order to foresee the magnitude order of the measured variables, we developed a theoretical one-dimensional description of the centrifugal blower, with this approach we can forecast, even if in an approximated way, the measured variables magnitude order. Obviously, in order to realize the blower and flow experimental characterization, it was necessary the choice of the right test rig.

1 Many motion based simulators have been developed in the last thirty years for many different types of vehicles [1] [2]. In order to make a simulation more realistic, linear accelerations and angular rates are exerted on the pilot by moving the platform on which the mock-up vehicle is located. The purpose of this article is to present a 7 DOFs (vertical, lateral and longitudinal displacements, roll, pitch and yaw angles and steer) motorcycle simulator which has been realized in Pisa, Italy, in the framework of the Esprit project by a consortium composed by industrial partners (Piaggio and Humanware from Italy and HEAD acoustics from Germany) and by academic partners (Scuola Superiore S. Anna from Italy, Halmstad University from Sweden and University of Bochum from Germany).

The paper presents an innovative drive-train for a small scooter, taking advantage of an hybrid (mechanical-electrical) structure. The single parts of this drive train have been dimensioned and the resulting system has been introduced in a simulation program. According to the simulation results the hybridisation is able to enhance the maximum power of the scooter by 1 kW (over 30%), without changing the fuel consumption, and to allow a pure-electric operation with a range over 11 km. Moreover, when the propulsion power comes only from the onboard batteries, and they are recharged from the electric mains, the operation cost per km is less than one half the cost of corresponding fuel consumption of a vehicle without hybridisation.