A gas engine working on the constant$-$volume cycle gave the following results during a one$-$

hour test run:

Cylinder diameter: $24cm,$

Stroke: $48cm,$

Torque: $770Nm,$

Mep: $7\mathrm{.}5$ bar,

Average speed: $220rpm,$

Average explosion per minute: $77(=n^{**}(K)),$

Gas consumption: $8k\frac{g}{h},$

Lower heating value: $43M\frac{J}{k}{g}_{\text{f}\text{u}\text{e}\text{l}\text{,}}$

Inlet and outlet temperature of cooling water: $25C$ and $60C$ respectively,

Cooling water used: $600kg$

Water specific heat: $4\mathrm{.}18k\frac{J}{k}gK.$

Determine:

The mechanical efficiency,

Indicated thermal efficiency,

Draw up a heat balance for the engine on minute basis $-$ MJ$/$min$-(f,Qe,Qw).$