Cold start system and start method for flexible fuel vehicle

Abstract

The invention relates to a cold start system and start method for a flexible fuel vehicle. The cold start system comprises an engine control unit, a fuel system and a fuel oil preheating module. The fuel oil preheating module comprises a water temperature sensor, a preheating indicator light, a power output module and a heating type oil sprayer. When a start switch is turned on, the preheating indicator light is firstly lightened, the water temperature sensor transmits a cooling water temperature signal to the engine control unit, the engine control unit calculates a duty ratio signal and judges whether the power output module needs to output power or not, the power output module outputs a current to the heating type oil sprayer, and the heating type oil sprayer heats ethanol fuel and feeds back a temperature signal of the heating type oil sprayer to the engine control unit at the same time so as to judge the preheating finish time.

Description

technical field [0001] The invention belongs to the field of engines, and specifically refers to a cold start system and a start method of an ethanol flexible fuel vehicle. Background technique [0002] Since ethanol flexible fuel vehicles use ethanol as the main fuel, cold starts are not ideal. Since the evaporation of ethanol stops at 12°C, the ethanol fuel cannot be atomized after being injected into the engine manifold. A homogeneous gas mixture cannot be formed. When entering the engine cylinder for ignition, the ethanol fuel cannot be ignited effectively at this time, which brings difficulty to cold start. [0003] In order to solve this problem, two schemes are usually used to heat the fuel oil of the engine fuel rail and the auxiliary fuel tank system. The fuel oil rail is used to heat the ethanol fuel above the evaporation point so that it can form an effective mixture; or the auxiliary fuel tank heating system is used. Ignite the engine with gasoline fuel from th...

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Problems solved by technology

[0008] The disadvantage of this solution is that when the fuel is heated, because the fuel cannot flow, the efficiency of heat conduction is low, resulting in local overheating of the fuel, and the heating time is too long

Using this starting scheme, it takes nearly 1 minute to heat the fuel. Moreover, since the fuel inside the engine injector cannot be heated, the first fuel injection of the engine cannot be ignited smoothly, which will cause higher emissions.

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