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คำตอบที่ 5
จาก http://www.futurefueltechnology.co.uk/HGV/what_is_lpg.php
What is LPG ?
Liquefied Petroleum Gas (LPG) is a by-product of the petroleum-refining industry and in the UK the definition covers both commercial propane and commercial butane. When put under a relatively low pressure, these gases turn to liquid and can then be stored easily in a variety of tanks. This is in contrast to other road-fuel gases like CNG (Compressed Natural Gas) and LNG (Liquefied Natural Gas), which either have to be cooled to extremely low temperatures (LNG) or put under very high pressures (CNG) to be stored.
In a full "vapour system", LPG (in its liquid form) is expelled under its own pressure from the tank through special piping to a pressure reducer (sometimes called a vaporiser). Here it is reduced to normal pressure and reverts to its gas form, travelling to an ECU-controlled valve that regulates how much gas is introduced to the engine.
In a "semi-vapour system" the fuel remains in its liquid form until the injector stage. An internal-pump in the tank maintains a constant pressure throughout the system and an ECU controls the injectors and how much gas is introduced. The liquid turns back into a gas as it passes through the injectors and into the engine via the inlet manifold. Despite the LPG remaining in its liquid form until the very last second, it is still entering the engine as a gas and is still, therefore, vapour-injection
There is, however, new technology being launched in late Summer 2005 which allows for true liquid-injection. The benefit to this is that the substitution ratio can be much higher - as high as 50:50 in fact! This means that instead of using, say, 1000 litres of diesel in a given period, a converted truck will use about 500 litres of diesel and approximately 650 litres of gas. Even though more fuel is used overall (because LPG has less energy than diesel), a large saving is made because of the difference in price.
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csm กับ ไทยก๊าซยนต์ ช่วยอธิบายด้านเทคนิค กับการติด lpg ร่วมกับดีเซล
