Abstract: A first aspect of the present invention provides a method for the preparation of 2-chloro-5-chloromethylpyridine, comprising: performing a cyclization reaction on 4,5-dichloro-4-methoxypentanenitrile in presence of a silicon compound and an acylamide compound to obtain 2-chloro-5-chloromethylpyridine. Another aspect of the present invention provides a method for preparation of 2-(chloromethyl)-5-(trifluoromethyl)-1,3,4-oxadiazole, comprising: performing a cyclization reaction on 1-(chloroacetyl)-2-(trifluoroacetyl)hydrazine in a presence of a silicon compound and an acylamide compound to obtain 2-(chloromethyl)-5-(trifluoromethyl)-1,3,4-oxadiazole. The silicon compound or/and acylamide compound provided by the present invention serve as cyclization reagents and have high efficiency.

Abstract: A vehicle hydraulic control system comprises a high-low pressure decoupling valve, a high-pressure control oil circuit including a main pressure regulating pilot solenoid valve connected to a transmission controller and used for regulating the main oil pressure according to the instructions of the transmission controller and a main pressure regulating mechanical valve, a low-pressure cooling and lubricating oil circuit, a mechanical pump communication with the high-pressure control oil circuit, and an electronic pump is in communication with the high-pressure control oil circuit or the low-pressure cooling and lubricating oil circuit by means of the high-low pressure decoupling valve. The main pressure regulating mechanical valve is used for guiding the flow output by the electronic pump and/or the mechanical pump in communication with the high-pressure control oil circuit to the low-pressure cooling and lubricating oil circuit according to the control of the main pressure regulating pilot solenoid valve.

Abstract: A vehicle hydraulic control system comprises a high-low pressure decoupling valve, a high-pressure control oil circuit including a main pressure regulating pilot solenoid valve connected to a transmission controller and used for regulating the main oil pressure according to the instructions of the transmission controller and a main pressure regulating mechanical valve, a low-pressure cooling and lubricating oil circuit, a mechanical pump communication with the high-pressure control oil circuit, and an electronic pump is in communication with the high-pressure control oil circuit or the low-pressure cooling and lubricating oil circuit by means of the high-low pressure decoupling valve. The main pressure regulating mechanical valve is used for guiding the flow output by the electronic pump and/or the mechanical pump in communication with the high-pressure control oil circuit to the low-pressure cooling and lubricating oil circuit according to the control of the main pressure regulating pilot solenoid valve.