Solid SCR (selective catalytic reduction) control system for diesel engine

The invention discloses a solid SCR (selective catalytic reduction) control system for a diesel engine, which comprises an ammonia supply system, an ammonia ejection control system, a CAN (controller area network) communication line and a catalyst, wherein the ammonia supply system comprises an ammonia reservoir and a pressure regulation valve; at the normal temperature, NH3 is stored in the ammonia reservoir in a solid mode; after the diesel engine beings to work, engine cooling liquid heats the ammonia reservoir via a cooling liquid pipeline; NH3 in the ammonia reservoir is released in a gas mode so as to reduce NOx in diesel engine exhaust; the ammonia ejection control system comprises an SCR controller, a flow metering control unit and a nozzle, wherein the SCR controller calculates the required ammonia ejection control flow according to the working condition of the diesel engine; the flow metering control unit is used for controlling ammonia flow fed into the ammonia nozzle; meanwhile, a thermal type sensor in the flow metering control unit is used for detecting the actual ammonia flow; the signal is fed back to the SCR controller to carry out feedback control on the ammonia flow; the ammonia is injected into a diesel engine exhaust pipe via the nozzle; and the NOx in the diesel engine exhaust is reduced in the catalyst so as to achieve the purpose of controlling NOx discharge.