| 摘要 |
<p>A piston 2 for a free piston engine generator comprises one or more elements arranged coaxially along a piston shaft 2c, the length of the piston being at least five times its maximum diameter, and at least one of the elements being formed from a magnetically permeable composite material having isotropic electrical resistivity at least twice that of electrical steel. The elements may comprise a ceramic piston crown 2d at one or each end of the piston, magnetically permeable core elements 2f, eg of a composite material such as Soft Magnetic Composite (SMC) having an isotropic electrical resistivity greater than 5.0 x 10-6 Ω.m, and spacer elements 2g of low magnetic permeability, eg of aluminium. Linear generator means (9, fig.5) may be provided around the cylinder (1). This arrangement is intended to provide improved free piston position control, more consistent combustion and improved electrical conversion efficiency.</p> |
