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.
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