Solution: as long as the gasoline in the tank is exhausted, the extra gasoline vapor in the tank can be fired into the cylinder by the negative pressure of the engine, and no gasoline vapor will overflow. Nowadays, electric vehicles are referred to as pure electric vehicles, namely, a car that USES a single battery as the energy source for energy storage. It USES the battery as the energy source to power the motor, which drives the motor and drives the car forward. In terms of appearance, electric cars are indistinguishable from everyday cars. The difference lies mainly in the power source and the driving system. Awarded a UK patent, Senior’s PURe® range of energy-efficient aluminium windows and doors is the first on the UK market to benefit from an enhanced thermal barrier manufactured from expanded polyurethane foam (PUR). Traditionally used in cladding and insulation products, the innovative use of PUR as a thermal barrier in windows and doors gives the PURe ® range the potential to achieve U-values as low as 0.71W/m2 K when calculated as a commercial CEN standard window and 0.93W/m2 K when calculated as a CEN standard door. It is generally believed that the v-shaped engine is a relatively advanced engine, which also becomes a symbol of the sedan grade. At present, the most common engines are the straight-line 4 cylinder (L4) and v-type 6 cylinder (V6) engine. In general, the V6 engine has a higher displacement than L4, and the V6 engine runs smoothly and quietly than the L4 engine. A V6 engine is usually mounted on a mid-grade sedan.