Diesel model D-245.7EZ is installed on PAZ-32053-07 buses.

Diesel model D-245.9EZ is installed on buses PAZ-4234 and PAZ-32053-07

The general arrangement of the engine is shown in Fig. 1.

Diesels use the common rail fuel system with electronic injection control, which provides environmental performance corresponding to the Euro-3 level by optimizing the workflow.

Longitudinal section of the engine: 1 - piston cooling nozzle; 2 - water pump; 3 - piston pin; 4 - connecting rod; 5 - cap; 6 - piston; 7 - cylinder liner; 8 - cylinder head cover; 9 - cylinder head; 10 - cylinder block; 11 - flywheel; 12 - crankshaft counterweight; 13 - crankshaft; 14 - oil receiver; 15 - oil pump

The engine includes:

  • - cylinder block with suspension;
  • - crank and gas distribution mechanisms;
  • - lubrication, power and cooling systems;
  • - pressurization, start-up devices, drives of electrical equipment and units.

The crank mechanism consists of: a crankshaft, pistons with piston rings and pins, connecting rods, main and connecting rod bearings, a flywheel.

The crankshaft is steel, has five main and four connecting rod journals.

Front and rear, the crankshaft is sealed with cuffs.

The piston is made of aluminum alloy.

A combustion chamber is made in the bottom of the piston. In the upper part, the piston has three grooves - compression rings are installed in the first two, and an oil scraper ring in the third.

An insert made of special cast iron is cast under the groove of the upper compression ring.

Piston rings. The upper compression ring is made of high-strength cast iron, in cross section it has the shape of an isosceles trapezoid, the second

conical compression ring.

On the end surface near the lock, the compression rings are marked "Top" ("TOR").

Box type oil scraper with spring expander.

Connecting rod - steel.

There are holes in the top end of the connecting rod and bushing to lubricate the piston pin.

The camshaft consists of a camshaft, intake and exhaust valves, as well as parts for their installation and drive: pushrods, rods, rocker arms, adjusting screws with nuts, plates with crackers, springs, racks and rocker axles.

The camshaft is driven by the crankshaft through timing gears

Diesel specifications

Engine model - D-245.7EZ or D-245.9EZ

Type Diesel, four-stroke, turbocharged and air-cooled.

Method of mixture formation - Direct fuel injection

Number and arrangement of cylinders 4, in-line, vertical

Cylinder displacement, l: 4.75

Cylinder firing order: 1-3-4-2

The direction of rotation of the crankshaft is right (clockwise)

Cylinder diameter / piston stroke, mm:

  • D-245.7ЕЗ - 110
  • D-245.9ЕЗ - 125

Compression ratio 17

Rated power, net, kW:

  • D-245.7ЕЗ - 85.0
  • D-245.9ЕЗ - 95.0

Rated speed, min-1: 2400

Maximum torque, net, Nm:

  • D-245.7EZ - 422
  • D-245.9EZ - 456

Speed at maximum torque, min-1:

  • D-245.7ЕЗ - 1000... 1500
  • D-245.9ЕЗ - 1500...1600

Minimum idle speed, min-1: 750...800

Maximum idle speed, min-1, no more than 2650

Ventilation system - Open

Lubrication system - Combined: under pressure from the oil pump and splashing

Cooling in the lubrication system - Liquid-oil heat exchanger

Oil filter - Full flow, non-separable, mod. FM 009-1012005 or М5101

High pressure fuel pump - СР3.3 (BOSCH, Germany)

Electronic diesel control unit - EDC7UC31 (BOSCH, Germany)

Nozzle - CRIN2 (BOSCH, Germany)

Coarse fuel filter - Preline PL 270 (MANN-HUMMEL GMBH, Germany)

Partial Fuel Filter - Mann & Hummel WDK962/12 or WDK962/14 (Germany)

Air filter - Air cleaner with paper filter elements

Supercharge system - With variable boost pressure and air-to-air charge air cooler

Turbocharger - C14 (Turbo company) C15 (Turbo company) or S200G (Schwitzer company, Germany)

Diesel cooling system - liquid, closed type, with forced circulation of liquid, thermostat and expansion m tank

Starting aids - Glow plugs and fluid heater