Shrekky wrote: A tricked up commer diesel? |
junior fisho wrote: How does a 4 cylinder have 8 pistons? Only in England |
nstead of one piston per cylinder, which requires four cycles per firing, opposed-pistons engines have two pistons per cylinder, both connected by levers with a single crankshaft. With two pistons per cylinder, working in opposite reciprocating action, there's no need for cylinder heads, which means less heat is lost in the combustion process.
The advantage is the engine can produce equal performance for less displacement and less emissions from pressure inside the cylinder than a four-stroke engine. Combined with gasoline compression injection there is an opportunity improve fuel economy significantly and reduce emissions of nitrous oxides and particulate matter.
Tagit wrote: Whilst we may have good market demand due to the fuel price difference in NZ, most markets don't have separate fuel taxes like we do and the engines would need to compete on a much more level playing field. Whilst I like diesels in general, I am not such a big fan of the new generation of super lightweight engines making close to 100hp per litre of displacement or more. Huge combustion pressures and not much metal around the cylinders plus lots of stress on the cooling systems. Electronics are as complex, or more so than the equivalent petrol engine. I can't see how these engines could win the war on weight, price, longevity, noise,reliability, maintenance costs, or fumes, so they need to win it on fuel burn, safety, and torque. But at the same time they need a slim design gearbox that will hold together reliably with 300hp 'worth' of diesel torque, and that is a challenge that has beaten some big companies to date. With diesel and petrol being similar prices in most markets I can see some challenges for these guys to break into the mass market. One advantage might be not having to carry two types of fuel on a superyacht with a big tender, but a lack of international servicing outlets will probably offset that wee gain. |
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