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With increasingly stringent emission requirement in China the evaporative emission legislation for motorcycles has been issued since July of 2008. According to the vehicle investigation two type effective solutions for EFI engine can be optional for this requirement: Passive system (not controlled by EMS) and active system (controlled by EMS). For passive system how to ensure enough purge flow but minimize the influence on mixture formation is the key and for active type, the point will focus on how to control and calculate the exact purge flow amount with the fluctuated intake air pressure for single cylinder engine. In this paper the strategy for both purge flow control solutions has been presented especially for single cylinder motorcycle engine.

In electric fuel injection (EFI) systems the intake air pressure is used as system load signal for calculating injection and ignition parameters together with engine speed. Part of an EFI system for motorcycles is a throttle body module with integrated pressure sensor. As motorcycle systems require smaller components than automotive applications the target for engineering is to minimize the component size and still fulfill other system requirements. Therefore the pressure sensor sampling point should be as close as possible to the throttle shaft to reduce the module size but with a sufficient distance to avoid signal distortion by unsteady flow. This paper describes how to find a suitable sampling position by combining static bench testing, dynamic vehicle testing and CFD analysis.

In the future more stringent emission regulations will enforce closed loop control of engine management systems for a large number of inexpensive low displacement motorcycles in markets like China and other Asian countries. Specific low cost Electronic Fuel Injection (EFI) systems have been developed or are under development to meet these requirements. This study presents a comparison of heated vs. unheated oxygen sensors in such a system. The exhaust gas temperature rise and variation during the emission test cycle in this class of motorcycles and its impact on the light-off time, the dynamic response behavior as well as other small engine specific parameters are investigated. Most experiments have been carried out on a 125cc motorcycle equipped with water cooled 4 stroke engine with 3 way catalyst.

Engine management systems (EMS) for small engines require some specific solutions that are different from EMS for automotive engines. The specific requirements are due to special behavior of these engines on one hand, and the need for cost saving by reduction of the number of components on the other hand. Some special functions for small engines are introduced: engine load detection for P-n system, ambient pressure detection, stroke detection and anti reverse rotation function. In single cylinder engines, the intake air pressure and engine speed signal fluctuate periodically. At first, the special behavior of these two signals is investigated for different working conditions. Then functions for load detection and ambient pressure estimation are designed based on intake air pressure signal, and functions for stroke detection and anti-reverse are developed on the basis of engine speed detection. Test results show that these functions work well.

This paper presents advanced planar ZrO2 oxygen sensors being developed at Robert Bosch using a modified tetragonal partially stabilized zirconia (TZP) with high ionic conductivity, high phase stability and high thermo-mechanical strength. Green tape technology combined with highly automated thickfilm techniques allows robust and cost effective manufacturing of those novel sensing elements. Standardization of assembling parts reduces the complexity of the assembly line even in the case of different sensing principles. The sensor family meets the new requirements of modern ULEV strategies like fast light off below 10 s and linear control capability as well as high quality assurance standards. High volume production will start in 1997 for European customers.