Squaring up to emission rules
By Stephen Howe
STRINGENT engine emission legislation, which will eventually cover tractors and other farm vehicles, is behind a new range of engines from Peterborough-based Varity Perkins.
Japan will be the first country to impose the new rules next year. Europe must comply by Jan 1999. So it is not surprising that the Perkins 700 Series has been developed in less than two years combining the experience of Varity Perkins and Iseki of Japan, explains Varity Perkins production manager Phil Dale.
Two models will be available immediately – the 57.6hp, 2.6-litre indirect-injection 704-26 and the 63hp, 3-litre direct-injection 704-30. A turbo-charged version – the 704-30DT is under development and will have an output of about 80hp.
All three models incorporate a new design of cylinder head, cylinder block, valve train, manifold, fuel injection pump and injectors.
Engine breathing and combustion characteristics have been improved by redesigning the inlet and outlet ports, by providing a higher valve lift and a new manifold design.
Combustion is enhanced further on the direct-injection engine by re-positioning the injectors as centrally and vertically as possible to give better fuel spray characteristics and fuel/air mixing. Helical inlet ports also help to achieve optimum swirl and flow characteristics.
Meanwhile, particulate emissions are reduced by the design of the new cylinder block which develops minimal bore distortion which, together with the piston and ring specification, reduces oil consumption.
The 2.6-litre engine has been designed for the materials handling market while the 3-litre naturally aspirated and turbo-charged versions are designed to meet the needs of tractor makers world-wide. *
Emission legislation – stage 1
Reduced emissions are incorporated on a range of four-cylinder engines from Varity Perkins. The 700 Series units will fit tractors and materials handlers.