Apparatus for testing spray and combustion performance of internal-combustion engines based on rapid compression-expansion machine

The present disclosure provides an apparatus for testing spray and combustion performance of an internal-combustion engine based on a rapid compression-expansion machine, which belongs to the testing field of internal-combustion engines. It includes a driving mechanism, a transmission mechanism, an engine cylinder, an air intake system and an exhaust system. The engine cylinder includes a piston, a cylinder block, a dual-fuel cylinder head and a multi-injector assembly. The piston is disposed in the cylinder block. The driving mechanism is connected with the piston through the transmission mechanism and drives the piston to linearly move back and forth along a vertical direction of the cylinder block. The dual-fuel cylinder head is connected to an upper part of the cylinder block. The multi-fuel injection assembly includes a plurality of injectors. The plurality of injectors are of the same type and are all disposed on the dual-fuel cylinder head.